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ABSTRACT NO.: 01

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Image fusion magnetic resonance imaging for improved orbital and ocular soft-tissue resolution in the dog

Douglas Esson*, Gwendolyn Lynch†, Matthew Fife‡, Sara Calvarese§ and Michael Broome* Eye Care for Animals, *Upland, †Culver City, ‡Tustin, §Las Vegas, NV, USA

Magnetic resonance imaging (MRI) is a well-established and noninvasive diagnostic modality, routinely used in veterinary medicine. Significant structural pathology and mass lesions affecting the orbit and globe are typically well defined by conventional MRI techniques; however, subtle inflammatory changes may be more difficult to diagnose. A single case each of canine episcleritis, extraocular myositis, optic neuritis, and orbital cellulitis are presented to illustrate the potential usefulness of image fusion MRI technology for highlighting inflammatory orbital and ophthalmic disease. Image fusion MRI offers improved orbital and ocular soft-tissue contrast resolution and improved two-dimensional definition of three-dimensional anatomic and physiologic data, without requiring additional anesthetic time or risk to the patient. This technique may be particularly useful for the evaluation of subtle or atypical inflammatory conditions affecting the orbit or globe.

ABSTRACT NO.: 02

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Advanced functional in vivo magnetic resonance imaging of the rat optic nerve

Douglas Esson*, Xeve Silver† and Mark Sherwood‡ *Eye Care for Animals, Upland CA; †McKnight Brain Institute and ‡Department of Ophthalmology, University of Florida, Gainesville, FL, USA

The exact pathology of optic nerve damage in glaucoma has not been fully elucidated. Programmed cell death (apoptosis) may result from an interruption in the flow of neurotrophic substances, which flow bidirectionally between the lateral geniculate nucleus in the brain and the neurosensory retina. Attempts to investigate this process so far have largely centered on immunohistochemistry of postmortem specimens. An improved understanding of these events underlies effective treatment strategies to safeguard healthy retinal ganglion cells. Magnetic resonace imaging (MRI) is a well-established diagnostic modality and newer developments are allowing the assessment of functional biological changes using this technology. By varying MR parameters, diffusion-weighted images can be collected, allowing diffusion within the tissues being imaged to be assessed; however, the generation of full-tensor neurological imaging has been prohibited by the difficulties associated with obtaining this type of data in live subjects. We used an 11T magnet and MAS software to investigate in vivo water diffusion in the optic nerves of five live rats. We were able to record values for fractional anisotropy and average diffusivity. This diffusion may be representative of optic nerve axoplasmic flow. Functional MRI may be a viable tool for the early detection and monitoring of glaucomatous optic nerve changes and may also offer a useful platform for the investigation of potentially neuroprotective compounds in vivo.

ABSTRACT NO.: 03

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Biochemical and immunocytochemical characterization of canine corneal cells cultured in two different media

J. J. Schorling*, I. P. Herring*, W. R. Huckle†, J. P. Pickett* and R. B. Duncan† *Virginia-Maryland Regional College of Veterinary Medicine Department of Small Animal Clinical Sciences, Blacksburg, VA; †Virginia-Maryland Regional College of Veterinary Medicine Department of Biomedical Sciences and Pathology, Blacksburg, VA, USA

Purpose:  This study aims to determine whether canine corneal cultures demonstrate superior growth when cultured in a fully defined epithelial selective medium, Epilife®, compared to Dulbecco's modification of Eagle's medium (DMEM) with fetal bovine serum (FBS), and to characterize cultured canine corneal cells.

Methods:  Superficial keratectomies were performed on three dogs. Samples were trypsinized to separate cell layers. Posttrypsinization, immunohistochemistry confirmed that epithelial cells had been released from the stroma. Both cell populations (presumed epithelial cells and stromal tissues) were cultured in DMEM with FBS or Epilife. First-passage cells were prepared for immunocytochemistry and polymerase chain reaction (PCR). Immunocytochemical staining for pancytokeratin, vimentin, and E-cadherin was evaluated, PCR amplification of cytokeratin 5 (CK5) mRNA was assessed, and products were statistically analyzed using the Relative Expression Software Tool (REST).

Results:  Primary presumed epithelial cells grew faster when cultured in DMEM with FBS compared to Epilife. Stromal tissue segments in Epilife failed to adhere to culture plates, indicating that this medium may inhibit attachment and growth of nonepithelial tissues. Staining of corneal tissue segments confirmed that epithelial layers were pancytokeratin and E-cadherin positive, while stromal cells were vimentin positive. Immunocytochemistry of cultured cells revealed that epithelial cells stained positively for pancytokeratin, vimentin, and E-cadherin, while stromal cells remained only vimentin positive. Greater amplification of CK5 mRNA from epithelial cells grown in Epilife compared to epithelial cells in DMEM with FBS was confirmed using REST.

Conclusions:  Based on PCR results, Epilife medium may support retention of the epithelial characteristic of CK5 mRNA expression better than DMEM with FBS.

ABSTRACT NO.: 04

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Retrospective evaluation of canine conjunctival mast cell tumors

M. M. Fife*, T. Blocker*, R. R. Dubielzig†, T. Fife* and K. Dunn‡ *Eye Care for Animals, Tustin CA; †College of Veterinary Medicine, University of Wisconsin, Madison WI; ‡North Kent Referrals, Kent, UK

Purpose:  This study aims to characterize the clinical behavior, histopathologic findings, and surgical outcome of conjunctival mast cell tumors in the dog.

Methods:  Cases of conjunctival mast cell tumor were identified from the COPLOW, Eye Pathology Laboratory and California Eye Care for Animals case records from 1997 to 2006. Patient signalment and history, surgical treatment, histologic grade of tumor, tumor margins, and clinical outcome were obtained from case records and client or veterinarian follow-up.

Results:  Thirty-three dogs with 35 conjunctival mast cell tumors were identified. Labrador (7) and Labrador crosses (5) were the predominant breeds affected. Average age was 8.5 years. Location of tumors included bulbar (12), dorsal palpebral (9), third eyelid (8), ventral palpebral (3), medial canthal (1), and unknown (1). The histologic grade of tumors was determined based on criteria set forth by Paitnik for grading of cutaneous mast cell tumor and included: 10 grade I, 20 grade II, 3 grade III, and 2 undetermined. Tumor margins were evaluated in 31 cases and reported as dirty margins in 25 cases, narrow in 5 cases, and clean in 1 case (enucleated). Follow-up data were available for 24 animals: 4 died of unrelated causes (20.25 months postoperatively), 2 developed tumor recurrence (8 and 24 months postoperatively), 15 were disease free (mean 21.4 months postoperatively), 5 were lost to follow-up, including the two animals with tumor recurrence (mean 13 months postoperatively). No animals included in the study were known to have died of mast cell tumor–related disease.

Conclusions:  Canine conjunctival mast cell tumors appear to have a predilection for the Labrador breed. A majority of the tumors were of low to intermediate grade and demonstrated relatively benign clinical behavior. Patients in this study responded well to conservative surgical resection.

ABSTRACT NO.: 05

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Comparison of intraocular pressure measurements following phacoemulsification using the Tono-Vet and Tono-Pen

A. L. Thompson*, P. A. Gerding*, S. G. Sisler* and D. Schaeffer† *Eye Care For Animals, Chicago, IL; †University of Illinois College of Veterinary Medicine, Champaign, IL USA

Purpose:  The objective of this study was to determine whethr the Tono-Pen (applanation tonometer) and Tono-Vet (rebound tonometer) measured statistically similar intraocular pressure measurements in eyes undergoing phacoemulsification.

Methods:  All patients included in this study received a complete ophthalmic examination, including slit-lamp biomicroscopy, indirect ophthalmoscopy, intraocular pressure measurements were performed using both the Tono-Vet and the Tono-Pen, and central corneal thickness measurement using an ultrasonic pachymeter. All eyes had intraocular pressure and central corneal thickness measurements taken immediately prior to surgery, 2 h following surgery and 1 day postoperatively. Statistical analysis was performed using paired t-tests. A P-value of < 0.05 was considered significant.

Results:  The mean presurgical intraocular pressure measurement was 11.9 mmHg (± 4.7) measured by the Tono-Vet and 12.2 mmHg (± 5.3) measured by the Tono-Pen. Mean intraocular pressure measurement for the 2 h postoperative time was 15.5 mmHg (± 11.7) measured by the Tono-Vet and 15.7 mmHg (± 12.5) measured by the Tono-Pen. Mean intraocular pressure measurement for the 1 day postoperative time was 10.9 mmHg (± 6.7) measured by the Tono-Vet and 12.4 mmHg (± 5.4) measured by the Tono-Pen. No statistically significant differences in intraocular pressure measurements between the two tonometers were found (P > 0.1).

Conclusion:  This study demonstrated that the Tono-Vet (rebound tonometer) did not measure statistically different intraocular pressure measurements compared to the Tono-Pen (applanation tonometer) in eyes that were undergoing cataract phacoemulsification.

ABSTRACT NO.: 06

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Detection of virulent feline herpesvirus-1 in the corneas of clinically normal cats

J. Stiles* and R. M. Pogranichniy† *Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Purdue University, West Lafayette, IN; †Department of Virology, Animal Disease Diagnostic Laboratory, Ames, IO, USA

Purpose:  This study aims to determine the replicative status of feline herpesvirus-1 (FHV-1) identified in the clinically normal feline cornea.

Methods:  Corneas were collected from 31 cats euthanized at an animal shelter (25 clinically normal, 6 with ocular disease or scarring) and two pathogen-free clinically normal research cats. Corneas were homogenized and separated into aliquots for virus isolation (VI) and real-time quantitative polymerase chain reaction testing (q-PCR). Samples positive on VI were confirmed with FHV-specific fluorescent antibody staining. Eight samples were examined with electron microscopy.

Results:  Six corneas from five clinically normal shelter cats were positive for FHV-1 isolation. One cornea had feline calicivirus isolated in addition to FHV-1. Eight corneas from clinically normal shelter cats were positive on q-PCR for FHV, with six of these eight being positive on VI. Two samples had FHV particles identified on electron microscopy.

Conclusions:  Virulent FHV-1 can reside in the clinically normal feline cornea and can be detected by VI and q-PCR.

Grant support:  Supported by Purdue SVM Small Animal Disease Research Fund.

ABSTRACT NO.: 07

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Effects on tear film dynamics of experimental feline herpesvirus infection

C. C. Lim*, C. M. Reilly*, S. M. Thomasy† and D. J. Maggs‡ *Veterinary Medical Teaching Hospital, University of California, Davis, Davis, CA; †2KL Maddy Equine Analytical Chemistry Laboratory, ‡Department of Surgical and Radiological Sciences, University of California, Davis, Davis, CA, USA

Purpose:  This study aims to determine the effect of primary feline herpesvirus (FHV-1) infection on tear film break-up time (TFBUT) and Schirmer tear test (STT) values, and to determine the relationship between these parameters and conjunctival goblet cell density (GCD), histological inflammation, and clinical disease severity.

Methods:  Six specific pathogen-free cats, without current or previous ophthalmic disease, were included in this study. Baseline values were obtained for GCD, TFBUT, STT, total disease score, and clinical and histological evidence of conjunctivitis. These parameters were reassessed at multiple time points for 29 days following inoculation with 3.2 × 107 plaque-forming units of FHV-1.

Results:  During the first week following viral inoculation, TFBUT and GCD decreased dramatically, while total disease score, and clinical and histological evidence of conjunctivitis increased in all cats. Total and conjunctival disease scores as well as histological evidence of conjunctivitis began to normalize after the first week; however, TFBUT and GCD continued to decline until 15 and 21 days postinoculation, respectively, and remained abnormal for the duration of the study. STT values remained elevated for 29 days following inoculation with FHV-1.

Conclusions:  Experimental primary FHV-1 infection induces qualitative tear film abnormalities, as measured by TFBUT and GCD. Tear film break-up time appears to provide a reasonable clinical estimate of GCD. The tear film remains unstable long after clinical improvement, suggesting that mucinomimetic therapy should continue after apparent clinical recovery, until TFBUTs have stabilized within normal limits.

Grant support:  Center for Companion Animal Health.

ABSTRACT NO.: 08

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Bilateral retinoschisis in a dog: a veterinary clinical application for optical coherence tomography

J. W. Pearce*, K. L. Narfström*, C. W. Hamm†, E. A. Giuliano* and C. P. Moore* *College of Veterinary Medicine, University of Missouri-Columbia, Department of Veterinary Medicine and Surgery, †Mason Eye Institute, University of Missouri-Columbia, Department of Ophthalmology, Columbia, MO, USA

Purpose:  This study aims to document a clinical case of bilateral retinoschisis in a dog and discuss diagnostic methods which contributed to disease characterization, diagnosis, and treatment plan.

Methods:  An 11-year-old neutered male Labrador Retriever-cross dog was presented to the University of Missouri-Columbia Veterinary Ophthalmology Service for suspected visual deficits. Complete ophthalmic examination was performed and ERG, OCT, and histopathology were obtained.

Results:  Menace response and pupillary light responses were intact OU. Indirect ophthalmoscopy revealed a smooth, bullous elevation of the inferior-temporal retina OU, measuring approximately 4 disc diameters (DD) OD and 1 DD OS. ERG revealed markedly reduced scotopic and photopic responses OD and slightly reduced photopic b-wave amplitudes OS when compared to a size-matched middle-aged dog. 30 Hz flicker responses were reduced more than 50% and the photopic negative response was lacking OD. Optical coherence tomography showed inner retinal separation consistent with retinoschisis. Lesions remained unchanged over 4 months at which time the dog was humanely euthanized for reasons unrelated to the ocular disease. Histopathology of the retina confirmed presence of retinoschisis OU with separation at the level of the outer plexiform layer. The inner retina and thickened internal limiting membrane were fused and inner retinal atrophy was apparent.

Conclusions:  This is the first case of canine retinoschisis with documentation of ERG changes and clinical confirmation using OCT. History, clinical and diagnostic findings, with absence of disease progression over time, are analogous with cases of acquired senile retinoschisis in humans.

ABSTRACT NO.: 09

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Canine optic nerve and retinal glioma: a retrospective clinical and pathologic study of 19 cases

R. R. Dubielzig, C. Naranjo and C. S. Shobert Comparative Ocular Pathology Laboratory of Wisconsin, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA

Purpose:  Tumors of the retina or optic nerve are rarely observed in dogs. This study was done to classify glial tumors observed in the retina and optic nerve of dogs. We describe the histopathological features and provide prognostic information.

Methods:  The records of the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) were searched for cases of canine optic nerve or retinal glioma. Clinical and follow-up information was gathered from submission forms and an extensive follow-up survey. Slides were reviewed to describe the histopathological characteristics of the neoplasm and classify them. Immunohistochemistry for Glial Fibrillary Acidic Protein (GFAP) was performed in all cases in which the paraffin blocks were available.

Results:  Nineteen canine glioma cases were included in the study. There was no breed or gender predilection. The mean age was 9.18 ± 3.63 years. The most common clinical manifestation was intraocular hemorrhage, which was seen in 14 cases. A mass lesion was detected in only nine cases. Of the 15 dogs where the glaucoma status was given, 10 had glaucoma. Follow-up information was available for 12 cases, eight of which were dead at the time of most recent contact, with a survival time ranging from 0 day (globes received after euthanasia) up to 20 months after enucleation. In six of the eight dogs that had died, tumor extended to the surgical margin in the optic nerve. All four cases where the dogs were still alive showed no tumor at this same margin. Two cases were classified as low-grade astrocytoma, five cases as medium-grade astrocytoma, 11 cases as high-grade astrocytoma, and one case as oligodendroglioma. GFAP was performed in 18 of the cases, and all but two were positive for this marker.

Conclusion:  Retinal and optic nerve gliomas must be considered in any differential diagnosis of intraocular and orbital masses. The metastatic potential is low, but ascending progression into the ventral aspect of the brain should is possible if the tumor is not completely excised.

ABSTRACT NO.: 10

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Combined effect of topical flurbiprofen and latanoprost on normal canine eyes: a controlled study

C. G. Pirie*, L. Maranda† and S. Pizzirani* *Department of Clinical Sciences and †Department of Environmental and Population Health, Tufts Cummings School of Veterinary Medicine, North Grafton, MA, USA

Purpose:  This study aims to evaluate the effect of topical flurbiprofen 0.03% (FP, Pacific Pharma) and latanoprost 0.005% (LAT, Pharmacia & Upjohn) on conjunctival hyperemia, pupil size, and intraocular pressure (IOP) in normal dogs.

Methods:  Ten experimental dogs free of ocular and systemic disease were used. Dogs underwent a 2-day adaptation period using artificial tears OU. The study consisted of three 1-week treatment periods, with a 2-week washout in between. Period 1: dogs received FP (8 a.m., 2 p.m., and 8 p.m.) in the treatment eye (TE) and artificial tears in the control eye (CE) for 5 days. Period 2: dogs received LAT (8 a.m.) and artificial tears daily for 5 days in the TE and CE, respectively. Period 3: dogs received LAT (8 a.m.) and FP (8 a.m., 2 p.m., and 8 p.m.) in the TE and artificial tears in the CE (8 a.m., 2 p.m., and 8 p.m.) for 5 days. Ocular parameters were assessed during adaptation and each treatment period (8 a.m., 11 a.m., 2 p.m., 5 p.m., and 8 p.m.), in addition to, 2 days posttreatment periods (8 a.m., 2 p.m., and 8 p.m.).

Results:  IOP was reduced in TE receiving LAT (median 33.80%), increased in TE receiving FP (median 10.19%), and reduced in TE receiving LAT + FP (median 26.02%), as compared to CE. Mild-moderate hyperemia was present in TE receiving LAT and LAT + FP. All TE receiving LAT and LAT + FP demonstrated miosis, followed by rebound mydriasis at 24 h, which persisted 48 h after discontinuation of therapy.

Conclusions:  Combined LAT + FP demonstrated a reduced IOP lowering effect as compared to LAT alone. However, FP demonstrated less of a reducing effect, as compared to previously reported combined LAT and prednisolone acetate 1% vs. LAT. FP increased IOP in TE as compared to CE.

Grant support:  Supported by the ACVO Vision for Animals Foundation.

ABSTRACT NO.: 11

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Round cell variant of feline ocular posttraumatic sarcoma: retrospective study

C. Naranjo, C. S. Schobert and R. R. Dubielzig Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA

Purpose:  Feline ocular posttraumatic sarcoma (FOPTS) is a recognized entity. Until now most descriptions of this entity have been of a spindle-cell variant, which arises from the neoplastic transformation of lens epithelial cells. The aim of this study is to characterize a new variant of FOPTS, the round cell variant.

Methods:  Forty-two cases diagnosed as round cell variant of FOPTS were retrieved from the Comparative Ocular Pathology Laboratory of Wisconsin. Signalment, history, clinical signs, and histopathological features were recorded, and a follow-up survey was faxed to the referring veterinarian. Immunohistochemistry for B-cell (CD79a) and T-cell (CD3) markers was performed on selected cases.

Results:  Mean age at enucleation was 11.8 ± 4.1 years. There were 28 neutered males, two intact males, nine spayed females, one intact female, and two of unknown gender. Right eye was affected in 18 cases, left eye was affected in 22 cases, and in two cases it was unspecified. The mean duration of clinical signs before enucleation was 5.8 ± 4.2 years. In 14 cases there was a known history of trauma, six of the cats were found as a stray with an already abnormally looking eye, three eyes had undergone an intracapsular extraction of the lens and one eye had received an intraocular injection of gentamycin. Regarding outcome information, 11 cats were alive, 17 were dead at the time of gathering the information, and 14 cases were lost to follow-up. There was obvious lens capsule rupture in 23 of the cases, in eight of the cases there was no evidence of lens tissue in the plane of section and in the remaining 11 cases the lens capsule appeared intact in the plane of section, but it was highly wrinkled and there was a mature to hypermature cataract in all of them. The main microscopic features of the tumor were (i) neoplastic round cells arranged in solid sheets circumferentially around the eye; (ii) a pattern of survival of tumor cells around blood vessels; and (iii) extensive coagulation necrosis of tumor tissue away from the zone of perivascular survival. Immunohistochemical staining showed that the neoplastic cells were lymphocytes but tumor infiltrates stained for both T cells and B cells and the neoplastic c population was not obvious.

Conclusions:  The traumatized feline globe is at risk of developing several distinctly different neoplasms. The spindle-cell variant has been previously described but the round-cell variant is described here for the first time. These are tumors of lymphocytes and have a distinctive distribution in the traumatized globe suggesting that the tumor first develops in the globe.

ABSTRACT NO.: 12

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Chronic ocular lesions associated with microbeam radiation therapy in an experimental rat study

Lynne S. Sandmeyer*, Amber Shiekh†, Elisabeth Shultke‡ and Bruce H. Grahn* *Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, †Department of Ophthalmology, College of Medicine, University of Saskatchewan, ‡Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, Saskatoon, SA, Canada

Purpose:  This study aims to describe the chronic ocular lesions associated with microbeam radiation therapy (MRT) in an experimental rat study.

Methods:  MRT was administered in bidirectional mode with a skin entry dose of 350 Gy. During irradiation in the lateral direction, the beam entered the head on the right with the center of the beam array 3 mm posterior to the center of the right eye. Twelve months after MRT ophthalmic examinations were completed on 37 treated (MRT+) and 16 control (MRT–) rats. Electroretinography was completed in two MRT+ and one MRT– rat. Light microscopic examination was performed on eyes of 16 MRT+ and 9 MRT– rats, and retinal and choroidal thicknesses were measured.

Results:  Clinical examinations revealed fundus pallor and retinal vascular attenuation in 33 of 37 right and 2 of 37 left eyes of MRT+ rats. Cataracts were present in the right eyes of 12 of 37 MRT+ rats. Electroretinography amplitudes were reduced in the eyes of MRT+ rats. Light microscopy revealed retinal lesions, which ranged in severity with loss of outer to inner retinal cell layers, in 16 of 16 right and of 8 of 16 left eyes MRT+ rats. The mean right retinal thickness of MRT+ rats was reduced.

Conclusions:  Eyes within the field treated with MRT develop retinal degeneration and occasionally, cataract. Crossed beam arrays with high-energy used in MRT may be an effective measure to destroy small blood vessels.

ABSTRACT NO.: 13

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A case of suspected iridocorneal endothelial syndrome causing secondary glaucoma in a dog

L. S. Sandmeyer*, C. B. Breaux†, L. D. Barnes‡ and B. H. Grahn* *Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, †Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, ‡Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri-Columbia, Columbia, MO, USA

Purpose:  Iridocorneal endothelial (ICE) syndrome is a rare disease in humans characterized by extension or proliferation of corneal endothelium over the trabecular meshwork and iris. Contraction of this membrane leads to distortion of iris structure. Blockage of the trabecular meshwork by membrane overgrowth or formation of peripheral anterior synechia by membrane contraction leads to secondary glaucoma. The purpose of this abstract is to present a case of suspected ICE syndrome in a dog.

Methods:  Complete ophthalmic examination and light microscopic evaluation of the enucleated globe were performed. Immunohistochemical labeling with antibodies to smooth muscle actin, factor-8-related antigen, and cytokeratin AE1/AE3 was completed on the affected globe, as well as a normal globe, a case of primary glaucoma, and a case of secondary glaucoma due to retinal detachment and formation of a preiridal fibrovascular membrane.

Results:  Ophthalmic examinations revealed progressive unilateral mydriasis, ectropion uvea, peripheral anterior synechia, and glaucoma nonresponsive to antiglaucoma medications. Light microscopic examination of the enucleated globe revealed glaucomatous retinal atrophy, iris atrophy, and obstruction of the filtration angle by a population of cells which were continuous with the corneal endothelium and extended over the iris surface. In the suspected ICE case, corneal endothelial cells were positive for cytokeratin AE1/AE3 which was not seen in the other types of glaucoma.

Conclusions:  The clinical manifestations and light microscopic findings are consistent with those reported for ICE syndrome. Immunohistochemistry supports a metaplastic transformation of endothelial cells into epithelial-like cells, which is the suspected underlying pathophysiology in ICE syndromes.

ABSTRACT NO.: 14

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The effect of photodynamic therapy on squamous cell carcinoma in a murine model: an evaluation of time between intralesional injection to laser irradiation

L. D. Barnes, E. A. Giuliano, J. Ota, L. A. Cohn and C. P. Moore Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri-Columbia, Columbia, MO, USA

Purpose:  This study aims to evaluate the influence of time between intralesional injection of Visudyne® (Verteporfin for injection, Parkedale Pharmaceuticals, Rochester, MI, USA) to laser irradiation on tumor growth regression using photodynamic therapy (PDT) for the treatment of squamous cell carcinoma (SCC).

Methods:  A commercially available SCC cell line (A-431) was injected into the dorsolumbar subcutaneous tissue of athymic nude mice. Mice were randomly assigned to 1 of 6 groups (n = 10/group). Tumors from mice in each treatment (Tx) or control (C) group were injected with 0.1 mg/cm3 of Visudyne® or solvent only (D5W). Tx and C groups 1, 2, and 3 were irradiated 1, 30, and 180 min after intralesional injection, respectively, with a light emitting diode (688 ± 10 nm, light density: 200 mW/cm2, light dose: 180 J/cm2). Relative change in tumor volume (RCTV) was compared between groups using Wilcoxon rank sum test (significance: P = 0.05) at the study's conclusion (day 21).

Results:  A lower RCTV was demonstrated in Tx1 vs. Tx2 mice (P = 0.039) and in Tx1 vs. Tx3 mice (P < 0.005). Although PDT-treated mice in groups 1 and 2 demonstrated a lower RCTV compared to their controls (C1 and C2), differences were not statistically significant possibly owing to small sample size or choice of solvent.

Conclusions:  Lower RCTV in mice irradiated immediately after Visudyne administration compared to those treated after a 30- or 180-min delay supports the current therapeutic protocol of immediate irradiation as used for the treatment of equine periocular SCC in client owned horses.

Grant support:  Supported by the University of Missouri-Columbia, Research Board Grant.

ABSTRACT NO.: 15

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Duration of corneal anesthesia with ophthalmic 0.5% proparacaine hydrochloride using a Cochet-Bonnet aesthesiometer in clinically normal horses

K. A. Kalf, M. E. Utter and K. L. Wotman New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA

Purpose:  The duration of corneal anesthesia and the time and degree of maximal anesthetic effect of 0.5% proparacaine hydrochloride was measured in clinically normal adult horses using a Cochet-Bonnet aesthesiometer.

Method:  Baseline corneal touch threshold (CTT) was measured in millimeter for one randomly selected eye of each horse using the aesthesiometer by applying the filament to the cornea at maximum length (60 mm), and decreasing in 5-mm increments until a consistent blink was elicited. Following baseline CTT measurement, 0.2 mL of proparacaine was instilled in the selected eye. CTT was measured within one minute following proparacaine administration, and every 5 min thereafter for 60 min.

Analysis:  A mixed-model analysis of variance with tested eye varying between subjects and measurement time varying within subject was used to test for main effects and any interaction between these factors. A contrast between means of baseline and subsequent CTTs identified duration of corneal anesthesia as the time beyond which there was no difference from baseline. Maximal anesthetic effect occurred at the time with the lowest mean CTT.

Results:  Duration of corneal anesthesia using proparacaine in horses was 30 min. Maximal anesthetic effect occurred within 5 min, although CTT never went to 0 in any horse at any time.

Conclusions:  Duration of corneal anesthesia in horses is shorter than in dogs, and degree of maximal effect was less than in cats and dogs, most likely due to increased sensitivity of the equine cornea compared to these species.

Grant support:  Supported by Raymond Firestone Trust.

ABSTRACT NO.: 16

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Dacryops (lacrimal cyst) in four Labrador Retrievers

J. Ota*, J. W. Pearce*, M. J. Finn†, G. C. Johnson‡ and E. A. Giuliano* *Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri-Columbia, Columbia, MO, USA; †Department of Veterinary Clinical Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, USA; ‡Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri-Columbia, Columbia, MO, USA

Purpose:  This study aims to describe four cases of dacryops in Labrador Retrievers.

Methods:  Four young Labrador Retrievers were presented with similar histories. Each had a slowly enlarging mass adjacent to the left medial canthus. Three of the dogs had mild epiphora associated with functional nasolacrimal obstruction.

Results:  Ultrasonography of the masses revealed they were each spherical, thin-walled, cystic structures. Cytology was performed in three cases and revealed mixed inflammation with no detectable microorganisms. Dacryocystorhinography revealed a normal nasolacrimal system, closely associated but not communicating with, the cystic mass in all cases. Surgical excision of each cyst was curative. The nasolacrimal duct was injured during excision in three of four cases necessitating placement of an indwelling nasolacrimal catheter for 2 weeks. Histopathology of the four cysts confirmed the diagnosis of dacryops.

Conclusions:  This is the first report of dacryops in the Labrador Retriever. Dacryops were located within the inferior, medial eyelid and periocular tissue in all cases. Laceration of the nasolacrimal system is a potential complication associated with surgical excision of dacryops in this location. Ectopic lacrimal tissue may be a predisposing factor for canine dacryops.

ABSTRACT NO.: 17

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Ophthalmic manifestations of subarachnoid hemorrhage in dogs: clinical findings and practical significance

E. A. Giuliano*, J. R. Coates*, D. M. Eifler* and K. R. Bulsara†‡, *Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri-Columbia, Columbia, MO; †Department of Surgery, School of Medicine, University of Missouri-Columbia, Columbia, MO; ‡Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, USA

Purpose:  To describe the ophthalmic manifestations of subarachnoid hemorrhage (SAH) in dogs with induced basilar artery vasospasm. The clinical findings in dogs are compared to those in people with SAH (Terson's syndrome) and pathophysiologic mechanisms to account for significant differences are proposed.

Methods:  Thirteen purpose-bred, adult female dogs were assigned to three groups: control (C) (n = 5 dogs); simvastatin and cyclosporinee (SC) (n = 4 dogs); and simvastatin (S) (n = 4 dogs). Autologous blood was injected twice at 24-h intervals into the cerebellomedullary cisternal subarachnoid space. Serial CSF analyses and angiographies were performed on day 0, 3, 7, and 10 postinjection. Treatment was initiated on day 1. Complete ophthalmic examination was performed on all dogs within 1–3 days of treatment initiation.

Results:  Basilar artery vasospasm was detected on day 3 in controls, to a lesser extent in group SC, and not in group S. Vasospasm resolved by day 7 in all dogs. Bilateral scleral hemorrhage predominantly localized to the temporal and nasal aspects of the globe (at the 3 and 9 o’clock position) was detected in 11 of 13 dogs. In all cases, anterior and posterior segment examinations were unremarkable without evidence of vitreal or chorioretinal bleeding. Scleral hemorrhage was first observed within 1–3 days of SAH induction and resolved within 7–10 days. Anatomic variations in vascular supply to the eyes of people vs. dogs likely account for differences in ophthalmic findings of SAH, specifically presence or absence of a central retinal artery and vein.

Conclusions:  To the authors’ knowledge, this is the first documented report of the ophthalmic manifestations of SAH in dogs. These findings are relevant to the small animal emergency practitioner, neurologist, and ophthalmologist. Subarachnoid hemorrhage should be suspected in dogs that have sustained trauma and present with scleral hemorrhage, particularly if the hemorrhage is bilateral and in the absence of other ophthalmic abnormalities.

ABSTRACT NO.: 18

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Canine lateral canthal hamartoma: a description of seven cases

C. Kafarnik and R. R. Dubielzig Comparative Ocular Pathology Laboratory of Wisconsin, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA

Purpose:  We describe the signalment, anatomic location, and the pathologic features of a new disease syndrome in dogs.

Methods:  The records of the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) were searched for cases of hamartoma in dogs. Cases of mesenchymal hamaromatous lesions of the periocular connective tissues were included if they had adequate histologic material to verify the diagnosis. Each case was examined by hematoxylin and eosin stain and trichrome stain. Clinical information regarding the signalment and the location of the lesions was abstracted from the submission requests.

Results:  Seven cases of dogs with mass lesions diagnosed as hamartoma were found in the files of the COPLOW records. There were five different breeds including three Golden Retrievers, the ages ranged from 6 to 10 years, and the sex was evenly divided. Six of seven lesions were at the lateral canthus, ranging in diameter from 0.6 cm to 2 cm. All contained normal appearing collagen rich connective tissue with some adipose tissue. Five also contain fully differentiated skeletal muscle tissue arranged in poorly formed aggregates or as individual muscle fibers. All have distinct margins but are not encapsulated.

Conclusion:  Canine lateral canthal hamartoma has not been previously described. All six cases were removed from the lateral canthus. All seven cases were mass lesions made up of fully differentiated, normal appearing fibroadipose connective tissue and five of the seven also had, at least some, skeletal muscle differentiation.

ABSTRACT NO.: 19

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The effect of a single dose of topical 0.005% latanoprost and 2% dorzolamide/0.5% timolol combination on the blood aqueous barrier in normal dogs

N. S. Johnstone McLean and D. A. Ward Department of Small Animal Clinical Sciences, University of Tennessee College of Veterinary Medicine, Knoxville, TN, USA

Purpose:  This study aims to determine the effects of 0.005% latanoprost and 2% dorzolamide/0.5% timolol on the blood aqueous barrier (BAB) in normal dogs.

Methods:  Baseline anterior chamber fluorophotometry was performed on eight normal dogs. Sodium fluorescein was injected and the dogs were scanned 60–90 min postinjection. Seventy-two hours following the baseline scan, one eye received one drop of latanoprost. Fluorophotometry was repeated 4 h after drug administration. Following a washout period, the identical procedure was performed 4 h after the administration of dorzolamide/timolol. The degree of BAB breakdown was determined by comparing the concentrations of fluorescein within the anterior chamber before and after drug administration. BAB breakdown was expressed as a percentage increase in the posttreatment fluorescein concentration over the baseline concentration: %INC (Fl) = {[(Fl)post – (Fl)baseline]/(Fl) baseline} × 100. The percentage increase in fluorescein concentration in the treated eye was compared to that in the nontreated eye using a paired t-test with significance set at P < 0.05.

Results:  Following administration of latanoprost, the fluorescein in the treated eyes increased 49% (± 58%) from baseline compared to 10% (± 31%) in the untreated eyes (P = 0.016). Following administration of dorzolamide/timolol, the fluorescein concentration increased 38% ± 54%) compared to baseline vs. 24% (± 38%) in the untreated eyes (P = 0.22).

Conclusions:  The results of this study show that topical latanoprost causes BAB disruption in normal dogs while topical dorzolamide/timolol has no effect on the BAB in normal dogs.

ABSTRACT NO.: 20

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Ophthalmic diseases in 543 Sapsaree dogs

K. M. Seo*, J. M. Chae*, W. T. Kim*, M. B. Jeong*, N. Y. Yi*, S. A. Park*, S. E. Kim*, Y. W. Park*, J. H. Ha† and K. I. Han‡ *Department of Veterinary Ophthalmology, College of Veterinary Medicine, Seoul National University, Seoul, South Korea; †Department of Genetic Engineering, Kyungpook National University, Daegu, South Korea; ‡Korean Sapsaree Association, South Korea

Purpose:  This study aims to investigate ocular diseases and normal ophthalmic findings in Korean traditional ‘Sapsaree’ dogs which were the Korean National monument and to provide reference materials for breeders and clinicians.

Methods:  A total of 543 Sapsaree dogs were randomly chosen without sex preference and were examined bilaterally using ocular equipment, including a direct ophthalmoscope, an indirect ophthalmoscope, a slit-lamp biomicroscope, a focal illuminator, an applanation tonometer and a fundus camera.

Results:  This study showed that the incidence rate of hyaloid vessel remnants, regarded as a change within normal variation, was 6.1% in Sapsaree dogs. Regarding abnormal ophthalmic diseases, persistent pupillary membrane was the most commonly observed ocular disease (8.3%). Other findings included cataract, postinflammatory retinal degeneration, corneal lipidosis, persistent hyperplastic primary vitreous, retinal dysplasia, entropion, simple keratitis, eyelid papilloma, eyelid laceration, eyelid melanoma, simple conjunctivitis, and corneal scar.

Conclusions:  In total, the incidence rate of ophthalmic diseases was 21.9%. Based on sex and age distributions, males had more ocular diseases than females, and Sapsaree dogs were more susceptible to eye diseases as they aged.

Grant support:  Supported by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD) (KRF-2006-E00153).

ABSTRACT NO.: 21

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Evaluation of a newly developed nested polymerase chain reaction test in the diagnosis of canine and feline ocular coccidioidomycosis

M. M. Ashton*, S. Dial†, C. Warren‡, Richard Dubielzig§ and Diane Loeffler¶ *Eye Care for Animals, †University of Arizona Veterinary Diagnostic Laboratory, ‡Animal Eye Doctors, §School of Veterinary Medicine, University of Wisconsin, ¶DVM-Path, Phoenix, AZ, USA

Purpose:  To evaluate the effect of sampling and extraction techniques on the sensitivity and the specificity of a nested polymerase chain reaction (PCR) for Coccidioides spp. on formalin fixed paraffin embedded (FFPE) tissue with ocular coccidioidomycosis.

Methods:  FFPE ocular tissue with a histopathologic diagnosis of coccidioidomycosis (n = 24) and aspergillosis, blastomycosis, cryptococcosis, histoplasmosis, encephalitozoonosis, protothecosis (n = 15) was obtained. Sensitivity: 8 positive samples sectioned (25, 30, and 50 µm). Xylene deparaffinization (XD) was performed. Effect of DNA extraction time, Time = 1, 2, and 3 h (batches 1, 2, 3). Effects of DNA concentration: Various aliquots of DNA were pooled. DNA concentration (ug/mL) confirmed by mass spectrophotometry. Effect of XD: 12 samples were double XD. Specificity: 12 negative samples were used. Flank (f) and nested (n) PCR: DNA template was added to a reagent-buffer mix (Universal [f] and species specific [n] primers and reagents). Negative and positive controls were included. Product confirmed with gel electrophoresis. Sensitivity and specificity were calculated.

Results:  Sensitivity = 0.125%, Specificity = 86%.

Conclusions:  Irrespective of sampling size and extraction techniques the sensitivity of the nPCR in detecting Coccidioides spp. was low.

Grant support:  Supported by ECFA residents fund, UnivAzVDLab Coccidioides Research Fund.

ABSTRACT NO.: 22

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Isolation of obligate anaerobic bacteria from ulcerative keratitis in domestic animals

E. C. Ledbetter* and J. M. Scarlett† *Departments of Clinical Sciences, †Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA

Purpose:  This study aims to determine the frequency of obligate anaerobic bacterial isolation from corneal samples of domestic animals with ulcerative keratitis and to characterize the historical, clinical, cytological, and microbiological features of culture-positive cases.

Methods:  Anaerobic bacteriologic culture and Gram stain were performed on corneal specimens from 330 consecutive domestic animals examined with suspect septic ulcerative keratitis. Additional corneal diagnostics included: aerobic bacteriologic culture for all species; fungal culture for ungulates; Mycoplasma culture, virus isolation, and/or feline herpesvirus polymerase chain reaction for cats. Historical, clinical, and cytological findings were correlated with microbiologic data.

Results:  Anaerobic bacteria were isolated from 13.0% of corneal samples (dogs, 14.0%; horses, 12.9%; cats, 7.9%; alpacas, 18.8%). The most frequent isolates were Clostridium, Peptostreptococcus, Actinomyces, Fusobacterium, and Bacteroides species. The majority of infections were mixed anaerobic and aerobic bacteria, unless antimicrobial therapy had been administered prior to presentation. The clinical appearance of anaerobic bacterial culture-positive cases was highly variable. Ocular trauma, pre-existing corneal disease, previous corneal surgery, and chronic dermatological disease were significantly (P = 0.05) correlated with positive anaerobic cultures in one or more species.

Conclusions:  The results of the present study demonstrate that obligate anaerobic bacteria are present within the intralesional flora of ulcerative keratitis in domestic animals. In most species evaluated, these bacteria were identified infrequently. Anaerobic bacterial infection of the cornea in domestic animals most frequently occurs in association with other ocular pathogens and previous corneal abnormalities.

ABSTRACT NO.: 23

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Antibodies against alpha A- and beta-crystallins in normal and cataractous dogs

N. Kanemaki*, E. Tsutsumi*, Y. Ichikawa*, H. Ochiai* and D. E. Brooks† *Veterinary Teaching Hospital, Azabu University, Kanagawa, Japan; †College of Veterinary Medicine, University of Florida, Gainesville, FL, USA

Purpose:  We evaluated serum antibody levels against alpha A- and beta-crystallins in dogs with various lens conditions.

Methods:  Sera were collected from a normal young beagle, five Japanese domestic Shiba dogs with lens sclerosis, six dogs with mature cataracts, and six dogs with hypermature cataracts. Normal lens material was obtained from six 1-year-old Beagles and stored at −80 °C. Frozen lenses were thawed, decapsulated, and homogenized in 0.1 m phosphate-buffered saline (pH 7.4). The homogenate was centrifuged at 15 000 g for 15 min and the water-soluble lens protein supernatant was collected. The lens protein was separated with 12.5% SDS-polyacrylamide gel electrophoresis (SDS-PAGE), and transferred to a nitrocellulose membrane. Antibodies against alpha A- and beta-crystallins were evaluated in all serum samples by Western immunoblot analysis. The secondary antidbody was HRP-conjugated, rabbit antidog immunoglobulin G (Sigma Chemical Co., St. Louis, MO, USA) and a substrate was either DAB (Sigma Chemical) or TMB (Atto Co., Tokyo, Japan). The identification of alpha A- and beta-crystallins was done using purified individual crystallins separated with Cepharose CL-6B gel filtration.

Results:  Alpha A- and beta-crystallins were successfully identified from the prepared lens protein by SDS-PAGE. Serum antibodies against beta-crystallins were detected at low levels in normal, sclerotic, and cataractous dogs. The serum antibody against alpha A-crystallin in hypermature cataractous dogs was relatively high compared to lens-sclerosis dogs and mature cataractous dogs.

Conclusions:  The formation of lens-crystallin antibodies may vary in connection with the maturation of cataracts in dogs.

ABSTRACT NO.: 24

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Effect of dexmedetomidine–butorphanol combination on Schirmer 1 tear test (STT1) readings in dogs

S. H. Jalomaki and E. V. Eskelinen Malmin Elainklinikka Apex, Helsinki, Finland

Purpose:  Drugs such as α2-adrenoreceptor agonists and opioids may cause transient dry eye in dogs. The purpose of this study was to evaluate the effect of dexmedetomidine–butorphanol combination on tear production using the Schirmer 1 tear test (STT1).

Methods:  A group of 10 dogs (five males and five females, eight different breeds; 1.3–2.3 years of age; weight 14–57 kg) were selected from patients to be screened for presumed inherited eye diseases and to be sedated for radiologic assessment for hip dysplasia. Dogs were treated with tropicamide (Oftan Tropicamide® 5 mg/mL, Santen, Finland) 30 min before ophthalmic examination (indirect ophthalmoscopy, biomiocroscopy and STT1). All the dogs included were ophthalmoscopically healthy and had normal presedation tear production (STT1 > 15 mm/min). Immediately following ophthalmic examination dogs were sedated with dexmedetomidine (Dexdomitor®, Orion-Pharma, Finland) 10 µg/kg IM and butorphanol (Torbugesic®, Fort Dodge Veterinaria, Spain) 0,1 mg/kg IM, both in the same syringe. Tear production was measured again 20 min after sedation. The presedation and postsedation STT1s were compared by Wilcoxon signed rank test.

Results:  There was no significant difference in STT1s between the left and right eye. The mean pre- and postsedation STT1s were 20.7 mm/min (16–30 mm/min) and 3.0 mm/min (0–13 mm/min), respectively. The decrease was statistically significant (P = 0.002).

Conclusion:  Dexmedetomidine–butorphanol combination dramatically reduces tear production in dogs. The eyes should be treated with artificial tears after sedation with dexmedetomidine–butorphanol combination.

ABSTRACT NO.: 25

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Ocular manifestation of disseminated histiocytic sarcoma in a dog

P. Mouser*, M. A. Owston*, M. E. Coster†, J. A. Ramos-Vara* and C. Betbeze† *Department of Comparative Pathobiology, †Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN, USA

Purpose:  This report describes the ocular clinical, pathological, and immunohisto-chemical findings in a case of disseminated histiocytic sarcoma in a 9-year-old Golden Retriever presenting for unilateral blindness and a mass in the left globe.

Methods:  Selected tissue sections were processed for immunohistochemistry using a labeled streptavidin-biotin method and incubated with a variety of antibodies including leukocytic markers.

Results:  Upon presentation, the left globe was blind with exophthalmia, dorsomedial strabismus, corneal ulceration, lens subluxation, and smooth nodular expansion of the ventrolateral sclera. Thoracic radiographs revealed multiple discrete pulmonary soft-tissue opacities and tracheobronchial lymph node enlargement. At necropsy, the globe had a firm, pale tan mass infiltrating the choroid and inner sclera. Masses were also present in the lung, heart, diaphragm, liver, kidney, and lymph nodes. Microscopically, pleomorphic polygonal to spindle-shaped, discrete neoplastic cells invaded the choroid, ciliary body, and sclera, with numerous karyomegalic and multinucleated giant cells. Tumor cells had marked anisocytosis and anisokaryosis with abundant eosinophilic cytoplasm, vesicular nuclei, and 1–5 distinct nucleoli. The mitotic index was 30 per 10 high power fields (×400) with bizarre mitoses present. Neoplastic cells had strong immunoreactivity to CD18, CD45, and lysozyme.

Conclusions:  Based on the multicentric lesion distribution, the cellular morphology, and the antigen expression of tumor cells, a diagnosis of disseminated histiocytic sarcoma with ocular involvement was made.

ABSTRACT NO.: 26

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Reference values for ophthalmic diagnostic tests, comparison of tear test methods, and conjunctival flora and cytology in the healthy guinea pig (Cavia porcellus)

M. E. Coster*, J. Stiles*, S. G. Krohne* and R. E. Raskin† *Departments of Veterinary Clinical Sciences, †Comparative Pathobiology; School of Veterinary Medicine, Purdue University,West Lafayette, IN, USA

Purpose:  This study aims to establish reference values for ophthalmic diagnostic tests, compare tear test methods, and evaluate conjunctival flora and cytology in 32 healthy guinea pigs of varying age and breed.

Methods:  Diagnostic tests included: phenol red thread tear test (PRT) I and II, Schirmer tear test (STT) I and II, central corneal touch threshold (CTT), intraocular pressure (IOP) by applanation tonometry, conjunctival aerobic culture, and conjunctival cytology. Rebound tonometry was evaluated in 10 eyes of 5 animals.

Results:  Reference values were: PRT I: 21.19 ± 4.14 mm/15 s; PRT II: 22.44 ± 3.26 mm/15 s; STT I: 3.36 ± 3.11 mm/min; STT II: 4.05 ± 2.75 mm/min; CTT: 19.22 ± 5.21 mm (7.32 ± 2.81 g/mm2); IOP: 18.27 ± 4.50 mmHg. Rebound tonometry yielded a lower IOP (6.10 ± 2.18 mmHg) than applanation tonometry (P < 0.001). Common conjunctival bacterial isolates included Corynebacterium, Streptococcus, and Staphylococcus spp. Cytology showed a majority of basal epithelial cells; lymphocytes were common.

Conclusions:  Reference data will assist in diagnostic testing for ophthalmic disease in guinea pigs. Due to its low reference value, the STT may not be clinically relevant. Reference values for IOP appear to be tonometer-specific in guinea pigs.

ABSTRACT NO.: 27

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Deep lamellar endothelial keratoplasty for equine corneal stromal abscesses: 57 cases (2003–2007)

C. E. Plummer, D. E. Brooks, M. E. Kallberg and K. P. Barrie Departments of Small and Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA

Purpose:  This study aims to evaluate the success of surgical excision of deep corneal stromal abscesses (DSA) in horses via the deep lamellar endothelial keratoplasty (DLEK) technique with replacement of the excised lesion with a partial thickness corneal lamellar allograft.

Methods:  Retrospective analysis of medical records of 57 horses with DSA treated by DLEK between 2003 and 2007.

Results:  Of 57 eyes undergoing the procedure, 50 healed following surgery without incident, with minimal resultant scarring and functional vision, during a mean follow-up period of 20 months. Six animals developed satellite lesions, or new foci of disease, adjacent to the excision site within the cornea postoperatively. Of those six, four progressively worsened despite continued medical therapy and suffered with persistent uveitis and were eventually enucleated. One resolved following extended medical therapy, and although the eye remained visual, it was also phthisical. One was returned to surgery for removal of the satellite lesion and healed quickly thereafter. The ultimate success rate for globe and vision preservation was 91%. Serious vision and/or globe-threatening complications occurred in 12% of cases.

Conclusions:  DLEK is an effective technique for surgical removal of DSA in horses and, in most cases, results in a visual, cosmetically acceptable globe. Diligent follow-up care is recommended to quickly identify recurrent lesions and institute appropriate therapy.

ABSTRACT NO.: 28

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Sudden acquired retinal degeneration, associated pattern of adrenal activity, and hormone replacement in three dogs: a retrospective study

C. D. Levin Lantern Publications, Oregon City, OR, USA

Purpose:  This study aims to describe the clinical and laboratory findings, hormone replacement therapy and outcome of three dogs with sudden acquired retinal degeneration (SARD).

Methods:  Data were collected retrospectively from the general practice charts of one female and two male dogs (all castrated) with persistent signs of PU, PP, lethargy, confusion, agitation/panting, aggression and obesity. Mean age = 11 years. An endocrine/immune (E & I) panel (National Veterinary Diagnostic Services, Menifee, CA) was performed for all dogs. Mean time interval from SARD onset = 4.58 months. Range = 4.0–5.75 months. Initial E & I panels identified low levels of immunoglobulins (IgA, IgG and IgM), low cortisol and elevated estrogen in all dogs. T3 and T4 fell within the bottom 28% of normal range. General practice veterinarians initiated hormone replacement with triamcinolone acetonide injectable glucocorticoid (Fort Dodge Laboratories, Overland Park, KS, or Bristol-Myers Squibb, Princeton, NJ, USA) followed by low-dose oral methylprednisolone (Vintage Pharmaceuticals, Charlotte, NC, or Pharmacia, Kalamazoo, MI, USA) and oral levothyroxine (Lloyd Inc., Shenandoah, IA, USA). E & I panels were repeated between 1.0 and 5.5 months. Mean interval = 3.5 months.

Results:  All dogs demonstrated a shift toward normal immunoglobulin, estrogen, and cortisol levels. T3 and T4 rose toward the mid-normal range in all dogs. Clients reported full resolution in 43% (mean) of clinical signs and ‘some improvement’ in an additional 36% (mean).

Conclusion:  These dogs demonstrated concurrent levels of elevated estrogen and low cortisol – a pathological pattern of steroidgenesis described as adrenal exhaustion. Clinical signs were associated with hyperestrogenism rather than hypercortisolism. Low-dose glucocorticoid and thyroid hormone replacement had a positive effect on both clinical presentation and laboratory findings.

Grant support:  Supported by Lantern Publications.

SexInitial cortisolRepeat cortisolNormal cortisolInitial estrogenRepeat estrogenNormal estrogenInitial IgA/IgG/IgMRepeat IgA/IgG/IgMNormal range IgA/IgG/IgM
Male0.521.161.00–2.50 µg/dL25.4024.28Male:43/817/8478/1353/127IgA 70–170 IgG 1000–2000 IgM 100–200 mg/dL
Female0.540.68 35.1935.1220.00–25.00 pg/ml49/989/9656/1049/102 
Male0.481.29 25.3225.11Female:43/781/8063/1106/114 
      30.00–35.00 pg/ml   

ABSTRACT NO.: 29

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Sudden acquired retinal degeneration, associated pattern of adrenal activity, and hormone replacement therapy in a brittany spaniel: a case report

C. D. Levin Lantern Publications, Oregon City, OR, USA

Purpose:  This study aims to describe the clinical and laboratory findings, hormone replacement therapy, and outcome of one dog affected with sudden acquired retinal degeneration (SARD).

Methods:  Animal studied: a 9-year-old neutered male Brittany Spaniel with escalating signs of lethargy, confusion, agitation, seizures, head tics, hirsutism, anorexia, and GI distress. Time interval from SARD onset = 3 years. The general practice veterinarian ordered an abdominal U/S and ACTH-suppression test (University of Illinois, College of Veterinary Medicine, Urbana, IL, USA), which were negative for Cushing's disease. An endocrine/immune (E & I) panel (National Veterinary Diagnostic Services, Menifee, CA, USA) identified low levels of immunoglobulins (IgA, IgG and IgM), low cortisol and elevated estrogen. T3 and T4 fell within the bottom 23% of normal range. The general practice veterinarian initiated hormone replacement with two low-dose injectable glucocorticoids: dexamethasone sodium phosphate (IVX Animal Health, St. Joseph, MO, USA) and triamcinolone acetonide (Bristol-Myers Squibb, Princeton, NJ, USA). These were followed by low-dose oral methylprednisolone (Vintage Pharmaceuticals, Charlotte, NC, USA) and levothyroxine (Lloyd Inc., Shenandoah, IA, USA). The E & I panel was repeated after three months.

Results:  The dog demonstrated a gradual shift toward normal immunoglobulin, estrogen, and cortisol levels. T3 and T4 demonstrated a gradual rise toward the mid-normal range. The owner reported complete resolution in 57% of clinical signs and ‘some improvement’ in an additional 44%.

Conclusion:  Three years after SARD onset, the dog described here demonstrated concurrent levels of elevated estrogen and low cortisol – a pathological pattern of steroidgenesis described as adrenal exhaustion. Low-dose glucocorticoid and thyroid hormone replacement had a significant positive effect on both clinical presentation and laboratory findings. The author provides a novel explanation for persistent clinical signs in a non-Cushingoid, SARD-affected dog.

Grant support:  Supported by Lantern Publications.

SexInitial cortisolRepeat cortisolNormal cortisolInitial estrogenRepeat estrogenNormal estrogenInitial IgA/IgG/IgMRepeat IgA/IgG/IgMNormal range IgA/IgG/IgM
Male0.710.881.00–2.50 µg/dL25.1525.07Male: 20.00–25.00 pg/ml52/927/9359/982/97IgA 70–170 IgG 1000–2000 IgM 100–200 mg/dL

ABSTRACT NO.: 30

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Feline uveal neuroglial tumors

P. Mundy and R. D. Dubielzig Department of Pathobiological Sciences, University of Wisconsin, Madison, WI, USA

Purpose:  A retrospective study to describe the signalment, clinical presentation, outcome, histiopathologic, and immunohistiochemical characteristics of a previously undescribed uveal neoplasm which we have named the feline uveal neuroglial tumor in a series of four cats.

Methods:  The four cats were identified from ocular histiopathologic submissions to the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW). Medical records were reviewed and data collected for age, sex, breed, laterality of lesion, main clinical complaints and outcome. Hematoxylin and eosin (H&E) slides were then examined as well as immunohistiochemistry (Chromogranin A, GFAP, Melan A, Synaptophysin and S100) staining carried out on all the cases. Follow-up information was obtained through telecommunications with the referring veterinarian.

Results:  The age range of the cats was 10–18 years, three of which were female spayed and one male neutered, all cats were domestic short hairs. The referring veterinarian in all cases reported a mass like lesion visible through the pupil, glaucoma in two cases and chronic uveitis in one case. All cats underwent enucleation of the affected eye. All the tumors were large white solid mass lesions extending from the uvea and effacing large portions of the globe. They were formed of highly pleomorphic spindle cells displaying anisokaryosis and karyomegaly. Tumor cells were also evident in some vortex vessels within the sclera and peripheral nerves in the uvea. All the tumors stained positive for S100, GFAP, Synaptophysin and chromogranin A but negative for Melan A.

Conclusion:  This combination of immune markers suggests the tumor is some combination of Schwann cells, astrocytes and neuronal origin.

ABSTRACT NO.: 31

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Fluorescein nasolacrimal transit time in ophthalmically normal dogs and cats

D. R. Binder and I. P. Herring Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, USA

Purpose:  This study aims to investigate nasolacrimal transit time (NLT) in ophthalmically normal dogs and cats.

Methods:  Seventy-three dogs and 36 cats were studied. Recorded variables included STT, gender, age, and weight. Skull index, skull conformation and snout length were recorded for dogs. Fluorescein was applied to the dorsal bulbar conjunctiva via two methods including using a wetted fluorescein strip (fluorescein strip test [FST]) and using a single drop of 0.2% fluorescein solution (fluorescein drop test [FDT]). The nares were monitored for 30 min and NLT was recorded when stain first exited. Animals were divided into four groups for analysis: Group 1: All FST animals. Group 2: FST animals, excluding those lacking fluorescein passage within 30 min. Group 3: All FDP animals. Group 4: FDT animals, excluding those lacking fluorescein passage within 30 min.

Results:  Group 1 dogs: NLT was 517 ± 622 s; significant variables included snout length, skull conformation and gender. Group 2 dogs: NLT was 230 ± 198 s; no variables affected NLT. Group 3 dogs: NLT was 341 ± 627 s; significant variables included snout length and skull conformation. Group 4 dogs: NLT was 85 ± 158 s; significant variables included age, snout length, and skull conformation. Group 1 cats: NLT was 296 ± 505 s. Group 2 cats: NLT was 90.5 ± 152 s. Group 3 cats: NLT was 42.3 ± 93.3 s. No recorded variables affected NLT in cats.

Conclusions:  Fluorescein NLT is affected by testing method. In normal dogs, several variables can affect NLT.

ABSTRACT NO.: 32

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Measurement of inflammatory mediators in aqueous humor following paracentesis of the anterior chamber in dogs

C. L. Pinard*, D. Gauvin†, M. Moreau*,†, J-P. Pelletier‡, J. Martel-Pelletier‡ and E. Troncy† *GRAC, Department of Clinical Sciences and †GREPAQ, Department of Veterinary Biomedicine, ‡Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Quebec, Canada, Osteoarthritis Research Unit, University of Montreal Hospital Center, Notre-Dame Hospital, Montreal, Quebec, Canada

Purpose:  This study aims to evaluate levels of prostaglandin E2 (PGE2), nitrites and nitrates (NOX), tumor necrosis factor-alpha (TNF-α) and expression of inducible cyclo-oxygenase (COX-2), nitric oxide synthase (NOS-2), and matrix metalloproteinases (MMP-3 and -9) in canine aqueous humor following repeated anterior chamber paracentesis (ACP).

Methods:  Four healthy adult beagles without ocular anomalies had ACP performed on both eyes at T0, T4, and T8 under general anesthesia. Intraocular pressures (IOP) were measured the day prior ACP, at T4, T8 and for three subsequent days. Levels of PGE2 and TNF-α were quantified by commercial ELISA kit, NOX by chemiluminescence, while mRNA of canine COX-2, NOS-2, MMP-3 and -9 was characterized by quantitative PCR. Statistical analysis for IOP, PGE2, and NOX was done with repeated measures anova.

Results:  The IOP decreased significantly at T8 (P < 0.05) and was below baseline values at D3 in both eyes. PGE2 concentration significantly increased (P < 0.0001) to plateau at T4. A marginal decrease in NOX levels was observed at T4 (P < 0.06), however, a significant increase was noted at T8 (P < 0.0001). COX-2 showed maximal expression at T8. TNF-α and NOS-2, MMP-3 and -9 levels of expression were undetectable at all time points.

Conclusions:  Following ACP, the PGE2 levels confirmed an inflammatory response characterized by an induction of COX-2. NOx production was also increased after facing a slight decrease suggestive of an inhibition of the constitutive production. Compared to the prostanoids, the NOX pathway took longer to be induced. MMPs were not detected in the early inflammatory process.

Grant support:  Supported by a grant from Pfizer Animal Health, Kirkland, Quebec, Canada.

ABSTRACT NO.: 33

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Ocular findings in servals and Western cougars

D. A. Ward and M. A. Foss College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA

Purpose:  This study aims to describe the normal ocular findings in adult servals and Western cougars.

Methods:  Anesthetic induction was achieved with a combination of ketamine, medetomidine, and butorphanol. Slit lamp biomicroscopy, indirect ophthalmoscopy, and applanation tonometry were performed. Schirmer tear tests and corneal diameters were measured. Refraction was measured with streak retinoscopy. Direct gonioscopic examinations and anterior segment and fundus photography were performed in selected animals.

Results:  Objective measurements (mean [SD]) in servals (n = 8) were: STT = 5.2 (4.0) mm wetting/60 s; IOP = 9.5 (3.3) mmHg; horizontal corneal diameter = 18.4 (0.5) mm; vertical corneal diameter = 18.3 (0.8) mm; refractive error =+0.5 (0.6) D. Objective measurements (mean [SD]) in Western cougars (n = 10) were: STT = 10.2 (6.1) mm wetting/60 s; IOP = 16.8 (3.1) mmHg; horizontal corneal diameter = 22.8 (2.9) mm; vertical corneal diameter = 21.9 (1.1) mm; refractive error =+0.5 (1.1) D. Aside from the round pupil, anterior segment exam in the servals was similar to domestic cats. The retinal area centralis contained a prominent greenish color. One animal had bilateral nuclear cataracts. The Western cougar anterior segment was similar to that of the serval. The cougar retinas often contained hyperreflective spots and streaks, and most individuals had hyperreflective green oval shaped areas in the area centralis.

Conclusions:  The eyes of normal servals and Western cougars have essentially round corneas, are nearly emmetropic, and have a retinal appearance similar to that of domestic cats. IOPs are similar to those of domestic cats. STT values were considerably lower than domestic cats, but this may have been influenced by the anesthetic protocol.

Grant support:  Supported by the University of Tennessee College of Veterinary Medicine.

ABSTRACT NO.: 34

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Examination of normal equine eyes for the presence of leptospires

S. Gesell*, S. Brem†, H. Gerhards* and B. Wollanke* *Equine Clinic, LMU Munich, Germany; †Bavarian Health and Food Safety Authority, Germany

Purpose:  Pars plana vitrectomy has been used to treat cases of equine recurrent uveitis (ERU), with much success at the University of Munich's Equine Clinic. Since its inception, as well as routine aqueous paracentesis on equine clinical patients, large quantities of intraocular material has been obtained and used for both diagnostic and research purposes. In a previous study equine eyes suffering from ERU demonstrate a high prevalence of leptospires (52%, n = 229). Antibody test results were positive in 90% (n = 426) of the cases. Intraocular antibody production was confirmed by a Goldman-Witmer-Coefficient greater than 8 in 78% (n = 46), and PCR identified leptospiral-DNA in 70% (n = 53) of the ERU-eyes tested. Although leptospires can only be isolated up to 9 days postinfection, ocular signs may not become apparent for months, or even years. This raises the question: Can viable leptospires persist within the eye without causing an immediate immune-reaction? A positive live- or DNA test result in an historically and clinically healthy eye coupled with negative leptospire-antibody results (serology) could explain the prolonged duration between the initial leptospiral infection and the outbreak of uveitis. Therefore, the goal of the present study was to determine if evidence of an intraocular leptospiral infection exists in ophthalmologically healthy eyes.

Methods:  Intraocular samples were taken from 168 healthy eyes from 100 horses and were tested for the presence of both leptospiral-antibodies (microagglutination test [MAT] and ELISA), and live leptospiral bacteria (culture). 120 healthy eyes (60 horses) from this group were also tested for the presence of leptospire DNA (PCR). Samples from 14 ERU eyes served as controls.

Results:  One eye (0.6%) from the 168 healthy eye samples tested antibody-positive in the MAT and ELISA; none of the cultures were positive (0.0%). Leptospiral DNA was detected (PCR) in 6 of 120 healthy eyes (5.0%). Antibody testing on these same samples were produced negative results. Antibodies were detected in 14/14 samples (100%; MAT), and 13/14 samples (93%; ELISA) from the control group. Cultures and PCR were positive in 8/14 samples (57%).

Conclusions:  Because antibodies were detected in only 1/168 healthy eyes, aqueous paracentesis should only be performed on ‘normal’ eyes under exceptional circumstances. Asymptomatic occupation of the vitreous by leptospires, if at all possible, is limited to isolated cases. Isolation of leptospiral DNA with concomitant negative antibody results, from healthy eyes, may suggest intraocular leptospiral infection that has escaped detection by the immune system.

ABSTRACT NO.: 35

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Ocular distribution and toxicity of intravitreal injection of triamcinolone acetonide in normal equine eyes

N. Y. Yi, J. Davis, J. H. Salmon and B. C. Gilger Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA

Purpose:  To determine the ocular distribution and toxicity of intravitreal triamcinolone acetonide (TA) in normal equine eyes.

Methods:  Six normal adult horses were injected intravitreally with either 10 mg (n = 2), 20 mg (n = 2), or 40 mg (n = 2) of TA. The opposite eye was injected with BSS as a control. Ocular toxicity was assessed throughout the study period by biomicroscopy, tonometry, indirect ophthalmoscopy and electroretinogram (ERG). Aqueous humor (AH) and plasma samples were also collected during the study. Horses were euthanized 7 (n = 3) or 21 (n = 3) days after injection, and the eyes were enucleated for histopathology. Vitreous humor (VH) samples were also collected after euthanasia. TA concentrations in AH, VH, and plasma were measured by HPLC.

Results:  Three control eyes and one TA eye developed inflammation after injection or collection of AH. Positive bacterial cultures were obtained from three of these eyes. No other inflammatory or degenerative changes were noted on examination. TA crystals were visible within the posterior chamber. No evidence of toxic damage was noted on histopathology. TA was detected in all AH and VH samples from treated eyes following injection. Drug was not detected in the plasma.

Conclusions:  There was no evidence of overt toxicity from intravitreal TA in normal horses and a single intravitreal injection resulted in TA ocular levels for up to 21 days. However, the risk for bacterial infections with intravitreal or anterior chamber injections in horses is high. Use of topical and systemic antibiotics after injection is recommended.

Grant support:  Supported by the North Carolina Equine Uveitis Fund and the State of North Carolina.

ABSTRACT NO.: 36

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Keratoconjunctivitis associated with Toxoplasma gondii in a dog

R. L. Swinger*, R. R. Dubielzig† and K. A. Schmidt* *Animal Eye Specialty Clinic, Miami, FL; †School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA

Purpose:  This study aims to describe a case of canine ocular toxoplasmosis involving only the cornea and conjunctiva. This was a bilateral and recurrent disease in a 12-year-old, spayed female Pug that presented with a 3-mm, raised, pink, axial corneal mass OD that had developed within 1 week. Current treatment for keratoconjunctivitis sicca (KCS) and pigmentary keratitis OU included tacrolimus 0.03% and neopolydex ophthalmic ointments (OU TID).

Methods:  A superficial keratectomy followed by cryotherapy was performed OD and a sample was submitted for histopathologic evaluation. Epithelial dysplasia and suppurative keratitis were diagnosed from the corneal biopsy and the lesion resolved without complication. Two months later, a yellow/tan conjunctival mass with moderate-severe associated diffuse chemosis and conjunctival thickening was discovered OD. A second tissue biopsy found necrotizing conjunctivitis with protozoal parasites. Complete blood count, a serum biochemistry panel, and neospora and toxoplasma titers were submitted.

Results:  Bloodwork was normal and titers were negative. Topical neopolydex ointment OD was discontinued and the conjunctivitis resolved after a 6-week course of oral clindamycin (10 mg/kg PO BID). Two months after completion of oral medications the dog presented with a 5-mm yellow/tan dorsal bulbar conjunctival mass and conjunctivitis OS. Histopathology provided a similar diagnosis and immunohistochemical staining confirmed Toxoplasma gondii as the etiologic agent. Repeated toxoplasma titers were negative. Oral clindamycin was again initiated and continued for 8 weeks. At this time, the original corneal biopsy was re-reviewed and protozoal organisms were subsequently discovered. The dog currently shows no evidence of ocular toxoplasmosis, nor has any indication of systemic disease. She is currently following the original topical medication protocol to control KCS.

Conclusions:  Toxoplasmosis has been reported in the dog to cause multiple ocular diseases including: retinitis, anterior uveitis, iridocylitis, ciliary epithelium hyperplasia, and optic nerve neuritis. To our knowledge, this is the first confirmed report of toxoplasmosis causing only corneal and conjunctival disease in the dog. We hypothesize that these localized lesions may be associated with topical immunomodulating therapy for KCS. Toxoplasmosis should be considered a differential for canine conjunctivitis and corneal disease and has the potential to manifest in one or both eyes.

ABSTRACT NO.: 37

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The effect of 1% topical nalbuphine on corneal sensitivity in normal equine eyes

K. L. Wotman and M. E. Utter New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA

Purpose:  Nalbuphine is an opiate partial agonist analgesic that has been shown to decrease corneal sensitivity in normal dogs. The purpose of this study was to assess the effect of topical 1% nalbuphine on normal equine corneas using a Cochet-Bonnet aesthesiometer.

Methods:  Ten healthy horses of varying breeds, sex, and ages ranging from 6 to 15 years old with normal ophthalmic examinations were included in the study. Baseline corneal touch threshold (CTT) was measured in millimeters for both eyes of each horse using the Cochet-Bonnet aesthesiometer following previously described methods. After baseline CTT measurement, 0.2 cc of 1% of nalbuphine solution was instilled in a randomly selected eye. The contralateral eye served as a control with 0.2 cc of artificial tear solution applied after baseline readings. CTT was measured within 1 min following nalbuphine or artificial tear administration, and every 15 min thereafter for 60 min. Five horses had CTT measurements of each eye taken 120 min after nalbuphine or artificial tear administration.

Results:  No significant difference was seen in corneal sensitivity using 1% nalbuphine when compared to the control eye at any time point. No tearing or redness occurred in any eye treated with 1% topical nalbuphine.

Conclusions:  Corneal sensitivity was not affected in normal horses using nalbuphine as opposed to results found in normal dogs. The topical treatment, however, was not locally irritating and 1% topical nalbuphine may be useful in painful horse eyes.

Grant support:  Supported by Region 15 Arabian Horse Association.

ABSTRACT NO.: 38

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Identification of ocular matrix metalloproteinases present within the aqueous humor and iridocorneal drainage angle tissue of normal and glaucomatous canine eyes

William L. Weinstein*, Ursula M. Dietrich*, John S. Sapienza†, K. Paige Carmichael‡, Phillip A. Moore* and Thomas M. Krunkosky§ *Department of Small Animal Medicine and Surgery, University of Georgia, Athens, GA; †Long Island Veterinary Specialists, Plainview, NY; ‡Department of Pathology, University of Georgia, Athens, GA; §Department of Anatomy & Radiology, University of Georgia, Athens, GA, USA

Purpose:  The purpose of this study was to identify MMP activity within the aqueous humor and iridocorneal angle tissue of normal and glaucomatous canine eyes.

Methods:  Aqueous humor samples from 32 normal and 26 glaucomatous canine eyes were obtained through aqueocentesis. Iridocorneal angle tissue was dissected from 16 normal and 5 glaucomatous canine eyes. Substrate gelatin zymography was performed using 2 µL volumes of aqueous humor samples and 10 µg weights of total protein from iridocorneal angle tissue. The presence of MMP activity bands was measured quantitatively by densitometry technique.

Results:  The quantity of latent MMP-2 within the aqueous humor of the glaucoma samples was significantly increased compared to the normal aqueous samples (P < 0.0001). MMP-2 active form was found to be significantly increased in the glaucoma tissue samples when compared to the normal tissue samples (P = 0.0044). MMP-9 latent form was also found to be significantly increased in glaucomatous tissue when compared to the normal eyes (P = 0.0002). Aqueous humor MMP-2 latent levels were elevated for both primary and secondary glaucomas (P < 0.0001). Primary glaucomas showed increased MMP-2 activity levels when compared to normal eyes (P = 0.0204). Secondary glaucomas showed an increase, but not a statistically significant increase, in MMP-2 active form (P > 0.05). Tissue latent MMP-9 levels were shown to be increased for both primary (P = 0.0020) and secondary glaucomas (P = 0.0276).

Conclusions:  These results support an association between elevated levels of intraocular MMP-2 and MMP-9 and the presence of glaucoma.

Grant support:  Supported by ACVO Vision for Animals Foundation and UGA Veterinary Ophthalmology Research Fund grants.

ABSTRACT NO.: 39

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Limited orbitotomy without transsection of the orbital ligament for zygomatic mucocele in three brachycephalic dogs

Y. J. Hong*, S. U. Jang*, J. H. Lee*, I. S. Jung* and K. M. Seo† *Royal Animal Medical Center, Seoul, South Korea; †Department of Veterinary Ophthalmology, College of Veterinary Medicine, Seoul National University, Seoul, South Korea

Purpose:  This study aims to determine the outcome and effect of limited orbitotomy without transsection of the orbital ligament for zygomatic mucocele in three brachycephalic dogs.

Methods:  A 5-year-old Shih Tzu and a 2-year-old Pekingese were presented for exophthalmos, strabismus, protrusion of the third eyelid on the left eye and painless left orbital swelling. In addition, a 2-year-old Shih Tzu was presented for swelling and discharge of surgical site enucleated for eyeball damage from a traffic accident 4 weeks ago. Fundic examination, ocular reflexes, and intraocular pressure revealed within normal limits. All cases were diagnosed as zygomatic mucocele by fine-needle aspiration and cytological evaluation of the fluid extracted from the facial mass. A limited orbitotomy without transsection of the orbital ligament was performed for excision of the multilobular cystic zygomatic salivary gland to provide ventral exposure to the orbit and to minimize trauma to the globe and supporting structures.

Results:  The outcome of surgery were excellent and all dogs had no significant postoperative complications. Until 6 months after surgery, they have been no recurrence.

Conclusions:  This report demonstrates utilization of an effective limited orbitotomy without transsection of the orbital ligament for zygomatic mucocele in three brachycephalic dogs. This surgery was easier to perform than previous surgical techniques for zygomatic mucocele.

ABSTRACT NO.: 40

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Analysis of brain-derived neurotrophic factor and its TrkB and p75 receptors expression in the retina of normal and glaucomatous dogs

S. Iwabe*, G. A. Garc’a-Sánchez†, C Vázquez Pelaéz‡ and N. Moreno-Mendoza* *Instituto de Investigaciones Biomédicas, UNAM, México City, México; †School of Veterinary Medicine, LSU, Baton Rouge, LA, USA; ‡Facultad de Medicina Veterinaria y Zootecnia, UNAM, México City, México

Purpose:  Brain-derived neurotrophic factor (BDNF) is a neurotrophin responsible for neuron development, maintenance and survival. In retina, BDNF helps in ganglion cell repair after severe damage. This suggests that IOP elevation induces axonal transport obstruction at the level of the optic nerve head, inhibiting the retrograde transport of neurotrophins to the GCR, and leading to cell death. The objective of the present study was to determine the expression pattern of BDNF, and its receptors TrkB and p75 in retina of normal and glaucomatous dogs.

Methods:  Immunofluorescence and real-time RT-PCR were performed to evaluate BDNF, TrkB and p75 proteins and mRNA levels, respectively, in normal and glaucomatous dogs’ retinas.

Results:  BDNF and both receptors protein were observed in the cytoplasm of RGC in both normal and glaucomatous eyes. BDNF protein was also observed in nerve fiber, photoreceptor, and outer nuclear and plexiform layers. TrkB and p75 receptors were localized in the nerve fiber and internal plexiform layer. The levels of RNAm were detected in normal and glaucomatous retinas. Only significant differences were detected in the BDNF mRNA expression between normal and moderate glaucomatous retina.

Conclusions:  The expression of BDNF mRNA in normal dogs confirms that this neurotrophin is essential to the normal function of mature retinal cells. The observation of different expression levels of proteins and mRNA from BDNF and its receptors in normal and glaucomatous retina suggests an important role in damaged cells and local neurotrophin synthesis which indicates retrograde transport of the neurotrophin to the RGC.

Grant support:  Supported by Conacyt Proyect no. 59225.

ABSTRACT NO.: 41

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Penetrating keratoplasty in the horse: visual outcome and ocular survival in 25 cases (2004–2007)

S. E. Blackwood, D. E. Brooks, C. E. Plummer, M. E. Kallberg, K. P. Barrie, A. Baker, C. M. Nunnery and N. C. Scotty Departments of Large and Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA

Purpose:  This study aims to evaluate the signalments, presenting complaints, surgical complications, and postsurgical outcomes of horse eyes undergoing corneal transplantation by full thickness penetrating keratoplasty (PK).

Methods:  A retrospective medical records study of full thickness penetrating keratoplasty in 25 horses presented to the University of Florida Veterinary Medical Center from 2004 to 2007.

Results:  The cases consisted of 25 horses (thirteen mares, five stallions, and seven geldings). There were eight Thoroughbreds, six Quarterhorses, two Paints, three Warmbloods, two Arabs, and four horses of other breeds. Of the 25 cases, 17 (68%) of the cases also had a conjunctival flap placed at the time of surgery; four (16%) also had an amniotic membrane graft placed at the time of surgery; and one (4%) had a conjunctival flap and amniotic membrane graft placed at the time of surgery. Full thickness PK was performed for iris prolapse (n = 12), severe ulcerative keratitis (n = 5), descemetocele (n = 3), keratoconus (n = 1), deep stromal abscess (DSA) (n = 3), and penetrating foreign body (n = 1). Frozen donor grafts were used in 96% of the eyes. Fungi were identified in eight eyes (32%) and bacteria in 10 (40%). The visual outcome was positive in 60% of the eyes (n = 15). Enucleation in two eyes (8%), phthisis bulbi in six eyes (24%), pupil occlusion in two eyes (8%), and retinal detachment occurred in two eyes (8%). Surgical complications requiring reoperation including microleaks, graft infection and graft dehiscence occurred in 12 eyes (48%). All grafts displayed some degree of rejection. The ocular survival rate for penetrating keratoplasties in this review was 92%.

Conclusion:  The corneal transplantation technique penetrating keratoplasty (PK) is a technically feasible and tectonically successful surgical technique in difficult keratopathies of the horse. When compared to other equine corneal transplantation surgical techniques (posterior lamellar keratoplasty and deep lamellar endothelial keratoplasty), this technique results in more complications post operatively and fewer visual horses. This is most likely due to the more severe nature of diseases in the cases that require PK as the surgery of choice.

ABSTRACT NO.: 42

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Etiologic testing of deep corneal stromal abscess following penetrating keratoplasty in the horse

T Miller Michau*, C. M. H. Colitz†, E. Belknap†, C. A. Barden†, C. Yin†, J. B. Salmon* and B. C. Gilger* *College of Veterinary Medicine, North Carolina State University, Raleigh, NC; †College of Veterinary Medicine, Ohio State University, Columbus, OH, USA

Purpose:  Corneal stromal abscess in the horse is a diagnostic and therapeutic challenge. The purpose of this study was to determine the etiology of deep stromal abscesses in the horse.

Methods:  The medical records of 26 horses that received a penetrating keratoplasty for a deep stromal abscess were reviewed. Results of cytology (Diff-Quik), aerobic and fungal culture and sensitivity, and histopathology (H&E, PAS, GMS), were recorded. Histopathologic blocks that had been fixed in 10% buffered formalin were prospectively submitted for nonquantitative PCR (nqPCR; Aspergillus, Fusarium, Universal) and quantitative PCR (qPCR) for fungal DNA.

Results:  All abscesses were located adjacent to the corneal endothelium. An infectious agent (fungal) was identified in 14 of 26 cases by cytology (n = 6), culture (n = 2), and/or histopathology (n = 10). nqPCR was positive in 22/25 cases. qPCR was positive in 10/25 cases. With combined diagnostic tests, fungal etiology was implicated in 24/25 cases.

Conclusions:  A fungal etiology was implicated in 96% of deep stromal abscesses in this study. Superficial culture and cytology are frequently negative in deep stromal keratitis. Histopathology from surgical specimens is more likely to provide a diagnosis, and fungal hyphae were identified in almost half of the cases. Fungal DNA amplified by nqPCR and qPCR implicated a fungal etiology in six cases and an additional five cases, respectively, in which an organism had not been previously identified. Since formalin fixation shreds DNA into small pieces, a combination of nqPCR and qPCR was useful in diagnosing banked samples in almost all cases.

ABSTRACT NO.: 43

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Transforming growth factor β2 in the aqueous humor of normal dogs and dogs with glaucoma

T. Miller Michau*, J. H. Salmon*, R. V. English† and B. C. Gilger* *College of Veterinary Medicine, North Carolina State University, Raleigh, NC; †Animal Eye Care Associates, Cary, NC, USA

Purpose:  The purpose of this study was to determine the concentration of TGF-β2 in the aqueous humor of normal dogs and dogs with primary and secondary glaucoma.

Methods:  Aqueous humor (AH) was collected via aqueocentesis from 32 dogs presented for glaucoma and 28 normal dogs. AH samples were analyzed to measure the total (latent plus active) and active concentration, respectively, of TGF-β2. Concentration of TGF-β2 was then determined using an ELISA.

Results:  Total and active TGF-β2 concentration in the AH of normal dogs was 2603.5 ± 1201.7 pg/mL (range: 1416.7–5153.3 pg/mL) and 211.1 ± 72.7 pg/mL (range: 137.8–435.6 pg/mL), respectively. Total and active TGF-β2 concentration in the AH of dogs with primary glaucoma was 4695.2 ± 2714.9 pg/mL (range: 1591.1–11 591.1 pg/mL) and 131.8 ± 44.3 pg/mL (range: 76.7–226.7 pg/mL). Total TGF-β2 concentration in the AH of dogs with secondary glaucoma was 5691.6 ± 2445.2 pg/mL (range: 2600–9615.8 pg/mL), respectively. Dogs with both primary and secondary glaucoma had significantly elevated aqueous humors concentrations of total TGF-β2 compared to normal dogs (P < 0.05).

Conclusions:  In glaucomatous eyes, increase in outflow resistance is due, in part, to an increase in various components of the extracellular matrix. High concentrations of TGF-β2 have been identified in the aqueous humor of humans with various forms of glaucoma and may result in the trabecular meshwork changes. This may also be the case in the dog.

ABSTRACT NO.: 44

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Multiple ophthalmic lesions and melanocytic neoplasia in white Doberman Pinschers

J. T. Bartoe*, D. T. Ramsey†, S. M. Petersen-Jones* and R. R. Dubielzig‡ *Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI; †The Animal Ophthalmology Center, Williamston, MI; ‡Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA

Purpose:  This study aims to describe common ophthalmic lesions noted on clinical and histopathological examination of white Doberman pinscher dogs.

Methods:  Eighteen white Doberman Pinschers were examined using: applanation tonometry, slit-lamp biomicroscopy, indirect ophthalmoscopy, and streak retinoscopy. Dogs were also evaluated grossly for cutaneous masses. Mass lesions of concern were excised and submitted for histopathology.

Results:  Ten male and eight female dogs were examined with a mean age of 4.2 years (range 10 months to 7 years). All dogs were observed to have at least one ophthalmic lesion. The most common ophthalmic lesions included: photophobia (n = 17), bilateral horizontally oriented ellipsoid dyscoria (n = 17), eyelid masses (n = 4), and translucent iridociliary cysts (n = 3). Other lesions included: iridal masses, persistent pupillary membranes, cataracts, retinal dysplasia, retinal degeneration, and dermal masses. Mean intraocular pressure was 13.67 mmHg (range 8–21 mmHg). Mean refractive error was −0.75 D (range −4.5 D to +3.0 D). Histologic evaluation of tissues was generally characterized by amelanotic to lightly pigmented sheets of small anaplastic round cells with: increased nuclear to cytoplasmic ratios, lacy chromatin patterns, multiple nucleoli, and high mitotic rates. Diagnosis in all cases was either melanocytoma or melanoma.

Conclusions:  White Doberman Pinschers appear to have an increased frequency of ophthalmic lesions including melanocytic neoplasms compared with Doberman Pinschers of alternate coat colors. Histopathologic features of these neoplasms more closely mimic the human nevus than melanocytic neoplasms reported in other canine breeds.

Grant support:  Supported by Michigan State University Faculty Development Funds and the Animal Ophthalmology Center Research Fund.

ABSTRACT NO.:45

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Doxycycline levels in preocular tear film of horses following oral administration

A. Baker, D. E. Brooks, C. E. Plummer and N. Szabo Departments of Small and Large Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, FL, USA

Purpose:  This study aims to determine the concentration of doxycycline (IVAX Pharmaceuticals, Miami, FL, USA) in preocular tear film following oral administration in horses as a possible therapeutic modality for infectious and keratomalacic equine keratitis.

Methods:  Eight broodmares without ocular disease from a Thoroughbred breeding facility were included in this study. Each mare received 20 mg/kg of doxycycline by mouth once daily in the morning for five consecutive days. Tears were collected 1 h after doxycline administration starting on day one of administration and continuing for 10 consecutive days. Doxycycline levels in the tears were measured with high pressure liquid chromatography (HPLC).

Results:  Doxycycline was present in the tears of each mare at low ug/mL levels with the highest concentration appearing on the third to fifth days. Doxycycline levels had fallen below quantifiable ranges by day 10. No significant systemic side-effects were noted in any of the mares.

Conclusions:  Oral doxycycline is present in preocular tear film of normal horses with noninflamed eyes and may be useful as treatment in equine ulcerative keratomalacia. The oral dose listed was tolerated well by the horses in this study. Further study is warranted to determine the specific therapeutic response in horses with active collagenolysis associated with ulcerative keratitis.

ABSTRACT NO.: 46

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Penetrating lamellar keratoplasty for corneal stromal abscess in the horse: a retrospective study of 21 clinical cases

A. Baker, D. E. Brooks, C. E. Plummer, M. E. Kallberg and K. P. Barrie Departments of Small and Large Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, FL, USA

Purpose:  This study aims to evaluate the success of split thickness penetrating lamellar keratoplasty (PLK) and subsequent corneal lamellar allograft in horses with an axial deep corneal stromal abscess (DSA).

Methods:  A retrospective analysis of medical records from 21 horses treated with a PLK for a DSA between 2004 and 2007.

Results:  Of the 21 horses included in the analysis, eight were mares, two were stallions, and 11 were geldings. The most common breeds represented were the Thoroughbred (six), Warmblood (four), and Quarterhorse (four). Twelve of the 21 horses (57%) were positive for fungi on histopathology of the excised abscess. Fungal cultures were negative from all histopathology specimens. Allografts ranged in size from 4 to 10 mm with 6 mm constituting the most common size. All horses healed with mild scarring of the graft and functional vision. The most common complication noted postoperatively was leaking of aqueous through the incision (five horses) which resolved with medical or surgical treatment. One horse necessitated a conjunctival graft followed by a penetrating keratoplasty for continued leakage of aqueous humor. Other complications noted were ulcerative keratitis of the epithelial flap, intrastromal allograft swelling, suture abscesses, and allograft endothelial detachment. The superficial epithelial flap initially vascularized to subsequently become opaque at a later point in the healing process. Success rate for globe preservation and functional vision was 21/21 (100%).

Conclusion:  PLK is an acceptable surgical technique for removal of DSA in horses. It is recommended for DSA in the central aspect of the cornea vs. the peripheral cornea where a deep lamellar endothelial keratoplasty may be more appropriate. PLK results in minimal scarring and functional vision in all of the cases examined.

ABSTRACT NO.: 47

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Corneal epithelial inclusion cyst in a llama: a case report

C. G. Pirie*, N. M. Parry† and S. Pizzirani* *Department of Clinical Sciences and †Department of Biomedical Sciences, Tufts Cummings School of Veterinary Medicine, North Grafton, MA, USA

Purpose:  This study aims to describe the clinical and histopathological features of an epithelial inclusion cyst in a llama.

Methods:  A 13-year-old Llama presented for evaluation of a corneal mass involving the lateral aspect of the right eye of 4 months duration. Complete ophthalmic examination revealed a 3 × 4 × 3 mm diameter, smooth, raised partially pigmented vascularized mass. The mass emanated from the limbal region at the 9 o’clock position, extending onto the superficial aspect of the right cornea. The superior aspect of the raised aspect of the mass was variably translucent with the inferior aspect being opaque, containing a yellowish fluid.

Results:  Complete physical examination and blood work were performed, which were unremarkable, aside from ophthalmic abnormalities. The mass was excised en bloc by a superficial lamellar keratectomy, followed by placement of a conjunctival advancement flap covering the keratectomy site. The mass was submitted for histological evaluation. Histopathology identified the mass to be a corneal epithelial inclusion cyst filled with necrotic squamous and neutrophilic debris. Surgical excision was complete and considered curative with no signs of recurrence 3 months postoperatively.

Conclusions:  Epithelial inclusion cysts may develop as a complication of trauma, previous ocular surgery, or be congenital in origin. There was no known prior ocular trauma; however, a previously performed corneal biopsy, 2 years prior for evaluation of recurrent epithelial ulcerations, may have been an initiating cause.

ABSTRACT NO.: 48

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Case report: canine melanoma of the nictitans gland

W. Onuma*, M. Endo†, T. Kuwahara*, N. Ito* and S. Namba* *Marble Veterinary Medical Center, †Veterinary Ophthalmic Service, Kunitachi Animal Hospital, Kunitachi, Japan

Purpose:  This study aims to report a case of canine nictitans gland melanoma.

Method:  A 10-year-old intact female mongrel dog was referred to Marble Veterinary Medical Center with a protruding nictitans and mild external strabismus of right eye. We expected orbital abscess or tumor, and treated with antibiotics/steroid topically and orally. Orbital abnormality was examined by ultrasonography, computed tomography and fine needle aspiration. Following the resection, the region was diagnosed histopathologically.

Result:  Ultrasonography and computed tomography demonstrated a mass at the gland of the nictitating membrane. Fine-needle aspiration revealed no neoplasmic cells from the region. Histopathological examination of the surgical specimen verified malignant melanoma. No ocular recurrence was observed, however, lumbodorsal subcutaneous tissue and mammary gland mass were found after surgery. Surgical specimens were diagnosed as subcutaneous malignant melanoma and mammary gland carcinoma. And the findings of chest X-ray film were suggestive of a pulmonary metastasis, which originated from the melanoma.

Conclusion:  Only a few reports have been described about the nictitans gland melanoma in dogs. We suspect the pulmonary mass is distant metastatic lumbodorsal subcutaneous or the nictitans gland melanoma. Although it is known that melanoma metastasizes to pulmonary area, its subcutaneous involvement is unclear. Further work is needed on this distant metastasis from the nictitans gland melanoma.

ABSTRACT NO.: 49

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The effects of medetomidine hydrochloride on the electroretinogram of normal dogs

J. C. Norman*, P. M. Barrett* and K. Narfström† *Eye Care for Animals, Scottsdale, AZ; †Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri-Columbia, MO, USA

Purpose:  This study aims to determine the effects of a standardized intravenous dose of an alpha-2 agonist (Domitor®, Orion, Finland) on the electroretinogram (ERG) response in normal dogs.

Methods:  Twenty-five normal dogs were used to collect ERG responses including a- and b-wave implicit times (IT) and amplitudes (amp) before and after administration of medetomidine. Dogs were dark adapted for 20 min and ERGs were obtained using the HMsERG (RetVetCorp Inc., Columbia, MO, USA). The QuickRetCheck protocol (Narfström) was employed to provide the following flash intensities: 10 mcd.s/m2, 3 cd.s/m2, and 10 cd.s/m2. ERGs were repeated after 375 µg/m2 of medetomidine intravenously. Statistical analysis of the difference between the responses before and after medetomidine at all flash intensities was performed using a mixed effects model for anova.

Results:  The P-value for the effect of medetomidine on each of the four ERG responses was < 0.01. The estimates of the effect of medetomidine were (+)1.35 ms (–)23 µV (+)3.16 ms, and (–)47 µV for the a-wave IT, a-wave amp, b-wave IT, and the b-wave amp, respectively.

Conclusions:  Medetomidine significantly prolongs the implicit time and lowers the amplitude response of both the a- and b-waves in normal dogs at all flash intensities examined. Clinical implications may not be dramatic enough to preclude its use.

ABSTRACT NO.: 50

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Proliferation of Streptococcus zooepidemicus and Pseudomonas aeruginosa within silicone tubing (Mila®) flushed with equine serum

S. Jacobi*, W. M. Townsend* and C. A. Bolin† *Departments of Small Animal Clinical Sciences, †Diagnostic Center for Population and Animal Health, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA

Purpose:  This study aims to evaluate if equine serum administered via a subpalpebral lavage system (SPL) supports proliferation of Streptococcus zooepidemicus or Pseudomonas aeruginosa.

Methods:  An intravenous catheter with injection cap was inserted into sterilized silicone tubing (Mila®). To mimic an SPL within the conjunctival fornix, the tubing was secured to an elevated platform. The tip of the tubing extended from the platform into a vial containing culture medium inoculated with approximately 1.3 × 108 P. aeruginosa or S. zooepidemicus. To mimic administration of medication, the tubing was flushed twice daily with equine serum, sterile saline (negative control), or culture media (positive control) followed by air. Incubation was at 25 °C or 37 °C. At 24, 48, and 72 h postinoculation, samples were obtained for bacterial culture from one tube for each experimental variant. The following sections were cultured: (i) tubing tip that had been submerged in the inoculated culture medium, (ii) tubing mid-section, and (iii) tip of the intravenous catheter. The experiment was performed in triplicate.

Results: S. zooepidemicus or P. aeruginosa were isolated from 100% of the tubing tips. S. zooepidemicus was isolated from 1 midsection flushed with broth incubated at 37 °C. All other samples were negative for growth of the inoculated agents.

Conclusions: S. zooepidemicus and P. aeruginosa do not proliferate within silicone tubing flushed with equine serum. Therefore, clinical utilization of an SPL to administer topical serum should not create an enhanced environment for bacterial proliferation.

Grant support:  Supported by Michigan State University, College of Veterinary Medicine, Freeman Fund.

ABSTRACT NO.: 51

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Treatment of feline eosinophilic-proliferative keratitis with topical cyclosporinee: 30 cases

A. K. Spiess*, J. S. Sapienza* and A. Mayordomo† *Long Island Veterinary Specialist, Plainview, NY; †Valencia, Spain

Purpose:  Eosinophilic keratitis is a chronic keratopathy caused by an immune-mediated response to an antigenic stimulus. Clinical diagnosis is confirmed by evidence of eosinophils and/or mast cells upon corneal cytology. The purpose of this study is to demonstrate the efficacy of topical cyclosporinee in eosinophilic keratitis.

Methods:  Thirty cats were treated with topical cyclosporinee (1.5%) between 1997 and 2006. A full ophthalomologic examination with fluorescein, Schirmer tear test, slit lamp biomicroscopy, applanation tonometry, and indirect ophthalmoscopy was completed in all animals. Eosinophilic keratitis was diagnosed by clinical appearance and evidence of eosinophils and/or mast cells granulocytes in corneal cytology. The corneas were treated with topical cyclosporinee (1.5%) twice (3/33) and three times (27/33) daily. The minimum period for follow-up was 3 months.

Results:  The age of the patients ranged from 1.6 to 13.3 years with a median age of 5.9 years. Twenty were neutered males and 10 were spayed females. The presented breeds were 26 DSH (86.6%), two DLH, one Siamese and one Maine Coon. The lesions presented in the right eye in 17 cats, eight in the left eye, and five were bilateral. Cytology revealed the presence of eosinophils in all corneal scrapings. Mast cells were seen in 21 eyes (70%), neutrophils in 10 (33.3%), lymphocytes in five (16.6%) plasma cells and macrophages in one eye. Marked improvement in the treated eyes was seen in 25 (83.3%) and mild improvement in two (6%) cats. Three (10%) animals did not respond to the treatment with topical cyclosporinee. Side-effects were noted in two cats. These animals developed blepharitis which was successfully treated with topical corticosteroids in one case and with commercially available cyclosporinee 0.2% (Optimune, Schering-Plough Animal Health Corp., Summit, NJ, USA) in the other cat.

Conclusions:  Based on our findings topical cyclosporinee (1.5%) is an effective treatment of eosinophilic-proliferative keratitis. All cases with poor response to treatment were associated with poor owner compliance. Chronic, often lifelong therapy with medications is thus recommended.

ABSTRACT NO.: 52

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Intracapsular lensectomy with sulcus intraocular lens implantation in dogs with primary lens luxation or subluxation

C. M. Stuhr and C. Forte Animal Eye Clinic, Wilton, CT, USA

Purpose:  This study aims to evaluate the frequency of postoperative complications including glaucoma and retinal detachment following elective intracapsular lensectomy with sulcus intraocular lens fixation (SIOLF) for primary lens luxation in dogs.

Methods:  The medical records of 19 dogs (20 eyes) that presented with acute lens luxation or demonstrated active progression of lens subluxation where owners elected lensectomy with SIOLF were reviewed. In each case intracapsular lensectomy was performed by cryoextraction with SIOLF of a polymethylmethacrylate (PMMA) lens via the ab interno approach. Emergency lensectomy was performed in eyes which presented with acute anterior luxation and secondary glaucoma. Elective lensectomy was performed on eyes that (i) demonstrated progressive subluxation but intraocular pressure (IOP) remained within normal limits; (ii) had anterior or posterior luxations with normal IOP; or (iii) if elevated IOP from pupillary block normalized immediately after initial medical management which consisted primarily with pupillary dilation. All eyes had intact visual reflexes after IOP was normalized.

Results:  Lensectomy with SIOLF was performed on 20 eyes in 19 dogs over a 7-year period from 1999 to 2006. Average age was 8.6 years (range 4–14 years); 55% (11/20) were terriers and the remainder were a variety of breeds. Patients were followed for an average of 29.2 months (range 1–92 months) after surgery. Retinal detachment or secondary glaucoma was observed in 1/20 (5%) and 5/20 (20%) eyes, respectively, with 1/20 (5%) exhibiting both. Preoperative IOP was 23 mmHg and preoperative status was equally divided between luxated and subluxated lenses. Surgery was performed more frequently as an elective procedure (18/20; 90%) due to normalized IOP vs. as an emergency procedure (2/20; 10%).

Conclusions:  Complications of glaucoma and retinal detachment after SIOLF in this study were less when compared to previously reported incidence rates in the literature for lensectomy alone. The high risks of postoperative glaucoma and retinal detachment seen in these reports may reflect the preoperative status where the effects of uveitis and overt glaucoma from lens shifting and pupillary block have already incurred significant damage to the optic nerve and drainage angle. In addition, this traumatic event increases the risk of intraoperative complications associated with IOL placement. Early surgical intervention with SIOLF may diminish these risks as well as result in an eye with better visual acuity than if emergency lensectomy without SIOLF is performed.

ABSTRACT NO.: 53

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A mutation in cep290 discovered causative for feline hereditary rod cone degeneration (rdAc) representing a new group of diseases affecting the connecting cilium

K. Narfström*, V. David†, C. P. Moore* and M. Menotti-Raymond† *College of Veterinary Medicine, University of Missouri-Columbia, Columbia, MO; †Laboratory for Comparative Genomics, National Cancer Institute, Frederick, MD, USA

Purpose:  This study aims to describe the mapping and characterization process in finding the gene defect for hereditary retinal degeneration of Abyssinian cats (rdAc).

Methods:  Affected cats were outcrossed and further backcrossed producing 18 F1 and 55 backcrossed individuals, used for linkage and candidate gene analysis. Thirty-nine candidate genes were examined with approximately 57 microsatellites. In the process of confirming the absence of linkage to any of the candidate genes, microsatellites were genotyped at random in the cat genome. When significant linkage was obtained, fine mapping was performed in the region using comparative genomics and by generating and comparing cDNA from RPE and neuroretina from affected and nonaffected cats.

Results:  Significant linkage on a chromosome that had none of the 39 candidate genes was observed. Utilizing traces from the feline 2X whole genome sequence, the region was fine mapped in silico and microsatellites were identified in the region on cat chromosome B4. A single nucleotide polymorphism was discovered, resulting in addition of 4 nucleotides to the mRNA transcript, a frame-shift and introduction of a stop codon truncating the CEP290 protein.

Conclusions:  The CEP290 protein is implicated with the connecting cilium affecting the transport of proteins between the photoreceptor inner and outer segments. A feline ‘ciliopathy’ that causes retinal degeneration will open new avenues for research into disease mechanisms and treatment modalities for this relatively new group of serious diseases affecting both cats, dogs, mice and humans.

Grant support:  Foundation Fighting Blindness, National Cancer Institute.

ABSTRACT NO.: 54

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Immunohistochemical detection and the correlations between matrix metalloproteinases-2 and -9, macrophage inflammatory protein-2, and tissue inhibitors of matrix metalloproteinases-1 and -2 in equine fungal keratitis

S. D. Boveland*, P. A. Moore†, J. Mysore*, U. Dietrich†, C. Jarrett‡ and K. P. Carmichael* Departments of *Pathology, †Small Animal Medicine and Surgery, ‡Anatomy and Radiology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA

Purpose:  This study aims to determine the role and correlations between matrix metalloproteinases (MMP)-2 and -9, macrophage inflammatory protein (MIP)-2, and tissue inhibitors of matrix metalloproteinases (TIMP)-1 and -2 in the pathogenesis of equine fungal keratitis.

Methods:  Normal (n = 9), fungal affected (FA; n = 26), and purulonecrotic without fungi (PN; n = 41) paraffin-embedded equine corneal samples were evaluated immunohistochemically for MMPs-2 and -9, MIP-2, and TIMP-1 and -2. The number of immunoreactive inflammatory cells (ICI) was counted. Statistical analysis was performed using chi-squared tests, Student's t-test, two-sided hypothesis test (α = 0.05), repeated measures analysis of variance, Tukey's test, and linear correlations.

Results:  MMP-2 and -9, MIP-2, TIMP-1 and -2 immunoreactivity was identified in the corneal epithelium of normal corneas, and in the corneal epithelium, inflammatory cells (neutrophils and macrophages), keratocytes and vascular endothelial cells in the FA and PN samples. MMP-2 and -9, MIP-2, TIMP-1 and -2 ICI was significantly higher in FA and PN samples compared to normal corneas. There was a positive correlation between MMP-2 and MIP-2, MMP-9 and MIP-2, and MMP-9 and TIMP-1 in ICI in FA samples. There was positive correlation between MMP-9 and MIP-2, MMP-9 and TIMP-2, MIP-2 and TIMP-1, and MIP-2 and TIMP-2 in ICI in the PN samples.

Conclusions:  Increased immunoreactivity of MMP-2 and -9 in FA and PN samples is indirectly related to MIP-2 through its role in neutrophil chemo-attraction. TIMP-1 and TIMP-2 are up-regulated in equine purulonecrotic and fungal keratitis most likely secondary to increased expression of MMP-2 and -9. The positive correlations between MMP-2 and -9, MIP-2, and TIMP-1 and -2 suggests that their collaborative activities play specific roles in the pathogenesis of equine fungal keratitis.

Grant support:  Supported by the Veterinary Ophthalmology Research Fund and VMES Veterinary Research Fund, University of Georgia.

ABSTRACT NO.: 55

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Staged Ahmed valve and diode laser cyclophotocoagulation for the treatment of primary glaucoma in the dog

J. R. Warren, R. J. Munger and R. D. Ring Animal Ophthalmology Clinic, Dallas, TX, USA

Purpose:  This study aims to evaluate staged gonioimplantation and diode cyclophotocoagulation (CPC) for the treatment of primary glaucoma in the dog.

Methods:  A retrospective analysis was performed by reviewing medical records for all dogs receiving an Ahmed valve between 2000 and 2006. Scar resection and laser CPC were performed when the Ahmed valve and adjunctive medical therapy were insufficient to maintain normal intraocular pressure. Dogs diagnosed with secondary glaucoma were excluded. Factors evaluated included signalment, vision retention, intraocular pressure control, iridocorneal angle appearance, time from valve placement to CPC and valve revision, and complications.

Results:  Twenty-five percent of patients remained visual in the operated eye greater than 2 years following the initial gonioimplantation. Seventy-six of patients were female with Bassett Hounds and Cocker Spaniels overrepresented. Seventy-five percent of patients presented after irreversible loss of vision in the fellow eye. Ages ranged from 2 to 14 years of age at the time of the implant. Elevated intraocular pressure requiring adjunctive medical and surgical therapy occurred in 35 patients within 1–10 months postgonioimplantation.

Conclusion:  Primary glaucoma is a complex disease requiring aggressive management. Staged Ahmed valve implantation and diode laser cyclophotocoagulation can help preserve long-term vision in canine primary glaucoma cases.

ABSTRACT NO.: 56

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Determination of the risk factors involved in lens diseases in captive pinnipeds

C. M. H. Colitz*,†, W. J. A. Saville†, M. S. Renner‡,§,¶, E. J. Chittick**, P. Clough§, S. Collins††, L. Dalton‡‡, C. Dold§§, S. Dugan¶¶, F. Knightly***, J. McBain††, J. Mejia‡,†††, P. Ollen-Hughes¶, B. Osborne¶, S. Osborn‡‡, T. Reidarson‡‡, M. M. Rodriguez‡, T. Schmitt†† and M. Walsh‡‡‡ *Animal Eye Specialty Clinic, West Palm Beach, FL; †The Ohio State University College of Veterinary Medicine, Columbus, OH; ‡Miami Seaquarium, Miami, FL; §Dolphin Research Center, Grassy Key, FL; ¶Theater of the Sea, Islamorada, FL; **Disney's Animal Kingdom, Orlando, FL; ††Seaworld California, San Diego, CA; ‡‡Seaworld Texas, San Antonio, TX; §§Seaworld Florida, Orlando, FL; ¶¶Eye Specialists for Animals, Denver, CO; ***Denver Zoo, Denver, CO; †††Mississippi State University College of Veterinary Medicine, Mississippi State, MS; ‡‡‡Atlanta Aquarium, Atlanta, GA, USA

Purpose:  Pinnipeds have a high incidence of lens diseases. All participating facilities have pinnipeds affected with these problems rendering many blind or requiring lensectomy. In order to evaluate risk factors associated with lens diseases in pinnipeds, a questionnaire evaluated various factors.

Methods:  Sixty-six California sea lions were included. All animals were evaluated by a DACVO (SD Denver Zoo; CMHC rest). Statistical analysis (SAS program) was performed.

Results:  Twenty-seven animals are females and 45 are males. Average age of animals is 12.84 years. Fifty of 59 animals (84.75%) were raised in captivity, 15.25% (9/59) were beached. Thirty-nine of 69 (56.52%) had no history of ocular disease, 30/69 (43.48%) have a history of ocular disease. Seven/47 (14.89%) have parents that were blind, the rest were unknown 40/47 (85.11%). Forty-one of 72 (56.94%) do not have lens disease and 31 of 72 (43.06%) have lens disease. Variables that may contribute to increased risk are: animals = 15 years of age, animals > 238 lbs, rocky pool walls, if housed at = 2 facilities, history of ocular disease or fighting, neutering males. Protective variables include tarp shade covering vs. cloth or no shade. Multivariate analysis is pending.

Conclusions:  Cataracts and lens luxations occur in captive and wild pinnipeds and have genetic and environmental causes especially sunlight. Since cataracts were primarily seen in animals over 15 years of age and they are exposed to chronic sunlight over the course of their lives, implementation of sun-protective shade (tarp of other ultraviolet-protective materials) should help to diminish the development of cataracts in these animals.

Grant support:  Supported by the Columbus Zoo and Aquarium and the Ohio State University's Matching Research funds.

ABSTRACT NO.: 57

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Comparison of two electroretinography systems used in dogs: the reticom and the HMs-ERG

M. B. Jeong*, W. G. Son*, Y. W. Park*, S. A. Park*, K. M. Seo*, C. P. Moore† and K. Narfström† *Department of Veterinary Surgery and Ophthalmology, College of Veterinary Medicine and BK21 Program for Veterinary Science, Seoul National University, San 56-1, Sillim 9-dong, Gwanak-gu, Seoul, South Korea; †Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri-Columbia, Columbia, MO, USA

Purpose:  This study aims to compare two different electroretinography (ERG) instruments used on the same animal in a clinical practice.

Methods:  Retinal function in both eyes of 12 healthy Miniature Schnauzers was evaluated under general anesthesia. Scotopic and photopic ERGs were recorded by a contact lens electrode with a built-in LED stimulator, part of a commercial ERG equipment (RETIcom, Roland Consult, Brandenburg, Germany), and a compact, portable mini-Ganzfeld ERG unit (HMs-ERG, RetVetCorp Inc., MO, USA), respectively, following published Guidelines for Clinical Electroretinography in the Dog. The ERG waveforms, a- and/or b-wave amplitudes and implicit times of recordings by the two ERG units were compared.

Results:  The waveforms of the ERGs obtained by the two ERG units were identical to those of previous studies. Except for the amplitude of the b-wave for scotopic low light intensity stimulation, the overall changes of ERG parameters recorded by the HMs-ERG unit in response to changes in the protocol as to light stimulation were very similar to those recorded by the RETIcom equipment. This was found most clearly for the photopic single flash and 31 Hz flicker responses. The results demonstrate that both ERG systems are comparable.

Conclusions:  Both ERG units are appropriate for routine veterinary clinical use. It is recommended, however, to establish ERG system-specific reference ranges for each laboratory and clinic using a 95% confidence interval in order to obtain reliable results especially when evaluating hereditary retinal degenerative disease processes.

Grant support:  Supported by Brain Korea 21 (BK 21) global internship.

ABSTRACT NO.: 58

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Interactive effects of ammonia and light intensity on ocular, fear, and leg health in broiler chickens

W. W. Miller*, H. A. Olanrewaju†, W. R. Maslin‡, J. P. Thaxton§, J. Purswell† and S. L. Branton† *Advanced Animal Eye Care, Memphis, TN; †AUSDA-ARS, Poultry Research Unit, Mississippi State University, Starkville, MS; ‡College of Veterinary Medicine, Mississippi State University, Starkville, MS; §Department of Poultry Science, Mississippi State University, Starkville, MS, USA

Purpose:  High gaseous ammonia is detrimental to poultry health under confined environments; ocular disease is common in chickens during the first 2 weeks of placement. Furthermore, welfare consultants have expressed concerns that low light intensity may cause damage to the lens, leading to blindness. The objective of the present study was to evaluate the interactive effects of ammonia and light intensity on ocular, fear, and leg health in broilers.

Methods:  We evaluated the interactive effects of inhalation of ambient air with elevated ammonia concentrations and different light intensities on eyes lesions and welfare (fear, leg-health) in day-old broilers under environmentally controlled conditions.

Results:  Our result indicated that ammonia concentrations at 25 and 50 p.p.m. induced eye lesions from day 7 of exposure. Lighting intensities alone yielded no significant eye lesions. The interaction of 50 p.p.m. ammonia and light-intensity of 2 and 20 lux for 14 days further exacerbated eye lesions. The effect of ammonia was more pronounced than that of light intensities. These conditions worsened linearly as duration of ammonia concentration exposure and light intensity increased from day 7 of exposure. The eye lesions induced by ammonia and light intensity interaction quickly decreased starting 1 week following 2 weeks of ammonia exposure.

Conclusion:  The data indicate that ammonia has the greatest detrimental effect on ocular health of young broilers although higher light intensities may exacerbate the effects of ammonia. Ammonia induced uveitis in chickens clears rapidly upon cessation to ammonia exposure and there were no effects of ammonia, light intensity or their interaction on fear and leg health.

ABSTRACT NO.: 59

The effects of 2% dorzolamide on corneal sensitivity, schirmer tear test, and corneal thickness on normal feline eyes

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R. D. Sturgeon, J. A. Hyman, R. E. Merideth, T. Blocker, G. L. Lynch and D. J. Schaeffer Eye Care for Animals, Overland Park, KS, USA

Purpose:  This study aims to evaluate the effects of 2% dorzolamide on central corneal sensitivity, tear production, and central corneal thickness in Domestic Short-hair (DSH) cats.

Methods:  The study population consisted of 30 clinically normal DSH cats. Treatment consisted of one drop of 2% dorzolamide solution to one randomly selected eye of each cat at 7 a.m., 1 p.m., and 7 p.m. for five consecutive days. The contralateral eye received one drop of balanced salt solution at the same time points. Following baseline measurement and drug application at 7 a.m., corneal touch threshold (CTT) was assessed at 1, 5, and 15 min using a Cochet-Bonnet aesthesiometer. Schirmer tear test I was measured OU prior to treatment at 1 p.m. Central corneal thickness was measured OU by ultrasonic pachymetry prior to treatment at 7 p.m. Data were analyzed using repeated measures anova.

Results:  Corneal touch threshold (CTT, + SEM g/mm2) in treatment eyes was significantly (P < 0.01) increased from a mean baseline value of 3.03 ± 0.18 g/mm2 to 4.79 ± 0.29 g/mm2 at the 1-min time point. Additionally, CTT in untreated eyes was significantly (P < 0.01) increased from a mean baseline value of 2.88 ± 0.16 g/mm2 to 3.42 ± 0.19 g/mm2 at the 1-min time point. CTT returned to normal OU by 5 min. Tear production and central corneal thickness were not significantly affected by 2% dorzolamide.

Conclusions:  Corneal sensitivity is temporarily decreased following application of 2% dorzolamide. Tear production and corneal thickness do not appear to be immediately affected by 2% dorzolamide.

ABSTRACT NO.: 60

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Canine lens instability surgical options. Part 1: capsular tension ring use for phacoemulsification and intraocular lens placement

S. G. Stone, D. A. Wilkie and A. J. Gemensky-Metzler College of Veterinary Medicine, Ohio State University, Columbus, OH, USA

Purpose:  The purpose of this study is to evaluate capsular tension ring (CTR) use for phacoemulsification and intraocular lens (IOL) placement in instances of lens instability.

Methods:  Four dogs presented with six lenses with zonular instability for phacoemulsification of early immature to hypermature cataracts. Breeds included Bichon Frise, Wire Fox Terrier, Boston Terrier, and a mixed breed. Ages ranged from 7 to 14 years. Lens instability was discovered intraoperatively during continuous curvilinear capsulorrhexis or during phacoemulsfication. Three eyes received CTRs after hydrodissection of cortex from capsule for stability during phacoemulsfication and three eyes received CTRs postphacoemulsification for capsule stability during IOL placement and for lens centration postoperatively.

Results:  CTR placement prephacoemulsfication improved lens stability during phacoemulsification. CTR placement postphacoemulsification improved capsule stability for IOL placement and IOL centration. One of six lenses was approximately 2–3 mm ventrotemporally decentered 2 weeks postoperatively; however, the IOL and CTR were in the bag and the IOL was in the visual axis. One of the capsules containing IOL/CTR was displaced anterior to the ventrotemporal pupil margin at moderate pupil size 1 day postoperatively and required a second procedure to replace the bag behind the iris. At 2 months postoperatively, the IOL remains in place and the optic is centered in the visual axis. All other eyes retained well-centered IOLs postoperatively (follow-up range 1–5 months) with no additional inflammation beyond typical postoperative uveitis.

Conclusion:  The CTR is effective for stabilizing a canine lens capsule of less than 180 degree subluxation/instability for phacoemulsification and IOL placement. CTR stabilization offers an alternative option to aphakia post-ICLE or ECLE procedures. Possible complications include IOL and/or bag decentration or luxation if zonular dehiscence progresses postoperatively. For profound zonular dialysis in humans, a CTR has been designed for additional scleral fixation. Other known possible complications of CTR placement per human literature include: cortical entrapment, CTR entanglement in the capsule, and CTR perforation through posterior capsule during insertion. Extended follow-up and a larger study population are necessary to determine longterm efficacy of this technique in the canine eye.

Grant support:  Supported in part by Acri.Tec®.

ABSTRACT NO.: 61

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A quantitative comparison of posterior capsular opacification in canine patients following intraocular implantation with polymethylmethacrylate and foldable acrylic lenses

J. L. Watson*, I. D. Bras†, T. R. Webb†, S. G. Stone‡ and W. J. Saville‡ *Animal Eye Clinic, Norwalk, CT; †MedVet Medical Center for Pets, Worthington, OH; ‡College of Veterinary Medicine, Ohio State University, Columbus, OH, USA

Purpose:  The purpose of this study was to quantitatively compare the type and extent of posterior capsule opacification (PCO) following polymethylmethacrylate (PMMA) and foldable acrylic intraocular lens (IOL) implantation in canine patients.

Methods:  Thirty-two canine patients (59 eyes) underwent phacoemulsification and IOL implantation with either PMMA (Ocularvision®) (39) or foldable acrylic (Corneal®) (20) lenses and were evaluated for development of PCO in the region of the optic and peripherally at 2 weeks, 6–8 weeks, 4–6 months, and 1 year postoperatively. Digital images were taken at each time interval and PCO values were determined using EPCO 2000 software. Regression analysis was performed using SAS software.

Results:  Optic PCO scores were lower for the acrylic lenses than the PMMA lenses at all time intervals, and were, respectively, postimplantation: 2 weeks, 0 and 0 (P < 0.1120); 6–8 weeks, 0.4192 ± 0.07459 and 0.2128 ± 0.9135 (P < 0.091); 4–6 months, 0.6681 ± 0.1236 and 0.1810 ± 0.1596 (P < 0.0246); and 1 year, 0.5074 ± 0.1513 and 0.7068 ± 0.2140 (P < 0.4603). The foldable acrylic lenses had lower peripheral PCO scores than PMMA up to 6 months postoperatively; however, the PMMA lenses had lower peripheral scores at 6 months to 1 year postoperatively. The peripheral PCO scores for PMMA and foldable acrylic lenses, respectively, postimplantation were: 2 weeks, 0 and 0 (P < 0.3969); 6–8 weeks, 0.4262 ± 0.0732 and 0.1939 ± 0.0897 (P < 0.0546); 4–6 months, 0.4989 ± 0.0917 and 0.6500 ± 0.1184 (P < 0.3241); and 1 year, 0.4299 ± 0.1239 and 1.0340 ± 0.1752 (P < 0.0146). An increased incidence of peripheral pearl-type PCO and cortical regrowth was observed with acrylic lenses while fibrous-type PCO was noted with PMMA lenses. Optic PCO formation was lower than peripheral PCO with both types of lenses. An increased rate of IOL decentration was observed with the acrylic lenses.

Conclusions:  Optic PCO scores were lower with acrylic lenses than with PMMA lenses at all time intervals. The peripheral PCO development at 1 year postimplantation was greater with acrylic lenses than PMMA lenses and is likely due to its smaller optic size. Overall, both IOL designs prevented significant optic PCO formation maintaining a PCO score < 0.7068 at 1 year postoperatively.

ABSTRACT NO.: 62

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The effects of experimentally induced feline herpesvirus-1 infection on feline ciliary and trigeminal ganglia

W. M. Townsend*, S. Jacobi*, S. H. Tai†, M. Kiupel†, A. Wise† and R. K. Maes† *Small Animal Clinical Sciences and †Diagnostic Center for Population and Animal Health, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA

Purpose:  This study aims to evaluate the effects of experimentally induced feline herpesvirus-1 (FHV-1) infection on feline ciliary and trigeminal ganglia.

Methods:  Twelve juvenile specific pathogen-free cats were inoculated with 1 × 105 TCID50 of the FHV-1 C-27 strain via the ocular and nasal routes. Three cats were controls. Four infected and one control cat were euthanized on days 6, 10, and 30. The trigeminal ganglia (TG) and ciliary ganglia (CG) were harvested for virus isolation (VI), a quantitative real-time polymerase chain reaction assay (RT-PCR), and routine histopathologic examination.

Results:  FHV-1 was detected utilizing VI in 2/4 CG, 3/4 TG, and 0/2 control samples on day 6; 2/4 CG, 2/4 TG, and 0/2 control samples on day 10; and 0/4 CG, 0/4 TG, and 0/2 control samples on day 30. FHV-1 was detected utilizing the RT-PCR assay in 4/4 CG, 4/4 TG, and 0/2 control samples on days 6 and 10, and in 1/4 CG, 4/4 TG, and 0/2 control samples on day 30. Histopathologic examination revealed mild inflammation within the TG during the acute phase of the infection.

Conclusions:  FHV-1 was detected within the CG. FHV-1 was present within the CG during the latent stage of the infection. The presence of FHV-1 within the TG induced mild inflammation. A higher number of virions were detected within the TG during latency than has previously been reported.

Grant support:  Supported by the Michigan State University College of Veterinary Medicine Companion Animal Fund.

ABSTRACT NO.: 63

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Phacoemulsification and implantation of a +14 diopter foldable intraocular lens in an adult horse

W. M. Townsend, S. Jacobi, M. Petersen-Jones and J. T. Bartoe College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA

Purpose:  This study aims to describe the surgical and visual results after phacoemulsification and implantation of a +14 diopter foldable intraocular lens (IOL) in the right eye of an adult horse.

Methods:  A 4-year-old Quarter horse mare presented to the Michigan State University Veterinary Teaching Hospital for evaluation of bilateral cataracts. A complete ophthalmic examination including slit-lamp biomicroscopy and indirect ophthalmoscopy was performed. The mare's vision was normal in the left eye and compromised in the right eye. Bilateral immature cataracts were present in both eyes. The extent of the cataracts was greater in the right eye than the left. After induction of general anesthesia, routine phacoemulsification was performed in the right eye. A +14 diopter, 22-mm diameter foldable acrylic IOL with a 12-mm diameter optic (Acri.Tec®) was then introduced into the capsular bag. The cornea was closed routinely.

Results:  The only postoperative complication experienced was ocular hypertension confined to the first 12 h postoperatively. The IOL remained within the capsular bag and centered within the visual axis. Streak retinoscopy performed on days 6 and 12 postoperatively revealed a refractive error of +2.5 diopters in the right eye. The presence of the cataract in the left eye precluded retinoscopy.

Conclusions:  Implantation of a foldable intraocular lens did not cause any operative or postoperative complications. A refractive error remained, but was diminished compared to the refractive error of an aphakic horse.

Grant support:  Supported by a grant from the Michigan State University College of Veterinary Medicine Equine Health and Performance Fund.

ABSTRACT NO.: 64

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Ocular lesions associated with systemic hypertension in dogs

R. L. Mathes, U. M. Dietrich and S. A. Brown College of Veterinary Medicine, University of Georgia, Athens, GA, USA

Purpose:  This study aims to characterize ocular findings and underlying diseases associated with systemic hypertension in dogs.

Materials and methods:  One hundred eleven medical records from dogs with systemic arterial hypertension (systolic blood pressure readings taken with a Doppler device were equal to or higher than 180 mmHg) diagnosed and treated at the University of Georgia Veterinary Teaching Hospital from 1990 to 2007 were reviewed.

Results:  Thirty-nine dogs of various breeds with no statistical breed or sex predilection were included in the study population. In those dogs, a complete ophthalmic examination including tonometry, slitlamp biomicroscopy, and indirect ophthalmoscopy was performed at the time of or within 2 months of the diagnosis of hypertension. Seventy-nine percent of the dogs (31/39) were over 8 years of age. Seventy-four percent (29/39) showed ocular changes consistent with hypertensive retinopathy. Ocular findings included tortuous vessels, focal intraretinal or diffuse hemorrhages, hyphema or vitreal hemorrhages, and bullous or complete retinal detachments. Bilateral lesions were found in 18 dogs and unilateral lesions in six dogs. Classification was not possible in five dogs. The most common underlying diseases in dogs with ocular lesions and hypertension were renal failure (10/29), hyperadrenocorticism (7/29), and renal failure with hyperadrenocorticism (3/29). Other diseases associated with hypertension included pheochromocytoma, diabetes mellitus, and mitral regurgitation. No underlying disease was found in one dog.

Conclusions and clinical relevance:  Ocular lesions in dogs with hypertension are probably more common than previously suspected. All dogs diagnosed with systemic hypertension should receive an ocular examination. Renal failure and hyperadrenocorticism are commonly associated with systemic hypertension in dogs.

ABSTRACT NO.: 65

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Comparative study of the lissamine green and rose bengal vital staining

N. Takiyama, Y. Okuno, Y. Hara and M. Uechi Laboratory of Veterinary Internal Medicine, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Japan

Purpose:  This study aims to compare the staining characteristics in ocular surface disorders using lissamine green B (LG) vs. rose bengal (RB).

Methods:  Four Beagle dogs without ocular disease were used for experimental corneal epithelium impairment and eight clinical cases (seven dogs and one cat) of corneal disease were evaluated. Experimental corneal epithelium impairment was induced with ethyl alcohol preceded by a topical anesthetic. All animals were evaluated with of 1%, 2%, 5%, and 10% LG (Wako, Tokyo, Japan) solution and of 1% RG (Wako) solution. One microliter of dye solution was instilled into the lower conjunctival sac. The eyes were examined with the slit lamp microscope (SL-203, Shin-Nippon, Tokyo, Japan) and graded the degree of staining according the Oxford grading scheme.

Results:  In the experimental models, corneal staining were detected 5% and 10% LG and 1% RG In all of the clinical cases, staining were observed at 5% and 10% LG and 1% RB. In three cases, staining were observed 2% LG. In all animals, LG stained area were similar to those of RG. The mean staining score of LG was 2.63 and RG was 2.81 (P = 0.91).

Conclusions:  Lissamine green staining would be useful to evaluate ocular surface, although it requires higher concentration than rose bengal. In the experimental models, LG needed higher concentration than in the clinical cases. It may be caused by dilution with topical anesthetic solution.

ABSTRACT NO.: 66

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Examination of cup-to-disc diameter and area ratio in dogs

A. Yamasak*, S. Maehara†, K. Tsuzuki* and Y. Izumisawa† *Veterinary Teaching Hospital and †Department of Small Animal Clinical Sciences, Rakuno Gakuen University, School of Veterinary Medicine, Hokkaido, Japan

Purpose:  The cup-to-disc (C/D) ratio is used to evaluate the optic nerve head, and especially, the progression of glaucomatous optic nerve damage in humans. In this study, we calculated the C/D diameter and area ratio in normal dogs, and examined the difference among breeds.

Materials and methods:  Fundus photographs of 405 dogs (573 eyes, 41 breeds) were used in this study. All dogs had no abnormalities in ophthalmic examination. The fundus photographs were taken by TRC50IX (TOPCON), and IMAGEnet2000 was used for their analysis. We measured vertical diameter, transversal diameter, and area of the optic disc and optic cup, and calculated each C/D ratio. We examined the difference between the left and right eyes, and the correlation with age. We examined the difference of C/D area ratio in nine breeds (Shih Tzu, Miniature Dachshund, American Cocker, Cavalier, Welsh Corgi, Golden Retriever, Shiba, Beagle and Yorkshire Terrier), which included at least 20 eyes.

Results:  In all dogs, the C/D ratio of vertical diameter, transversal diameter and area were 0.46 ± 0.07, 0.48 ± 0.07, and 0.23 ± 0.06 (mean ± SD), respectively. There was no significant difference between the left and right eyes, and no correction with age. There were significant differences among many breeds, and especially Shih Tzu showed significant differences from seven breeds but not Golden Retriever.

Conclusion:  Since there was no difference between the left and right eyes, we consider that C/D ratio is useful for diagnosis of ophthalmic disease of one eye. The results suggested that C/D ratio differs among breeds, and so we consider that there is a need to take the breed into consideration, when evaluating C/D ratio.

ABSTRACT NO.: 67

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Retinal degeneration characterized by decline of cone response in four miniature Long-haired Dachshunds

S. Maehara*, A. Yamasaki†, K. Tuzuki† and Y. Izumisawa* *Department of Small Animal Clinical Sciences and †Veterinary Teaching Hospital, Rakuno Gakuen University, School of Veterinary Medicine, Hokkaido, Japan

Purpose:  The objective of this study was to examine retinal degeneration characterized by a decline in cone response in miniature Long-haired Dachshunds.

Materials and methods:  Four miniature Long-haired Dachshunds were included in this study. Ophthalmic examination and ERG were performed in all dogs. Fluorescein angiography was performed in three dogs. The same examinations were performed 6 months after the first examination in three dogs.

Results:  In obstacle course testing, behavior disorder was seen in one dog under illumination, and normal function was seen in the other dogs. All dogs had a positive reaction in menace response and PLR, but various degrees of decrease were seen. On funduscopy, abnormal reflectivity of the tapetal fundus and attenuation of retinal vessels were observed in all dogs. These abnormalities were marked in the peripheral fundus. In all dogs, normal or slightly reduced ERG was recorded in rod ERG and combined ERG, while markedly reduced or nonrecordable ERG was recorded in cone ERG and 30 Hz flicker cone ERG. On fluorescein angiography, only attenuation of retinal vessels was seen, and no inflammatory or neoplastic lesions were observed. No particular change was observed at examination 6 months after the first examination in all dogs.

Conclusion:  This study revealed retinal degeneration characterized by cone dysfunction on ERG in miniature Long-haired Dachshunds. Rod-cone dystrophy and cone-rod dystrophy have been reported in this breed. In all four dogs in this study, the fundus was similar to the early stage in a previous study, but there were different findings in ERGs and disease progression.

ABSTRACT NO.: 68

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Two canine cases with epiphora diagnosed as meibomian glands dysfunction

A. Saito, Y. Umeda, S. Wakaiki and Y. Ito Triangle Animal Eye Clinic, Toyko, Japan

Purpose:  The known functions of meibomian glands secretion include formation of tear film lipid layer and contribution to formation of lacrimal lake by coating the eyelid margin. It is thought that the meibomian gland secretions also play a varying role in a lacrimal retention to the ocular surface. However, in veterinary medicine, the clinical condition of meibomian gland dysfunction (MGD) has not been clarified. In this report, we summarize two cases diagnosed as MGD among the cases that the chief complaint was unilateral epiphora.

Materials:  Two 1-year-old, Miniature Dachshunds developed unilateral epiphora in the left eye several months prior to presentation. They had been treated with antibiotics and corticosteroids or nonsteroidal anti-inflammatory drugs (NSAID) by the referring veterinarian. Epiphora and mild chemosis were observed in left eye at the initial examination in both cases, but there was no detectable photophobia or pain. Mild corneal opacity and diffuse fluorescein staining (superficial punctate keratopathy) were observed with a slit lamp biomicroscope. In addition, thickening of the eyelid margin, regression of the mucocutaneous junction, and constriction of the meibomian gland apertures were observed as well as a viscous meibomian gland secretion. These two cases were diagnosed as MGD from findings described above.

Methods:  Oral doxycycline and topical fradiomycin sulfate–betamethasone sodium phosphate ointment were prescribed for case 1. Oral doxycycline and topical hyaluronate were prescribed for case 2, and hot compress and massage of eyelid margin were directed.

Results:  After treatment for 2 and 3 weeks, respectively, epiphora and eyelid margin thickening were improved in both cases. Fradiomycin sulfate–betamethasone sodium phosphate ointment was continued in case 1 for 1 month, and hyaluronate instillation, and eyelid hot compress and massage were continued in case 2. After treatment for 2 and 3 months, respectively, there was no recurrence of epiphora, and remarkable improvement was found in corneal transparency in both cases.

Conclusions:  These two cases developed the unilateral epiphora that did not respond to antibiotic instillation, corticosteroid, and NSAID. We suspected MGD based on thickening of eyelid margin, regression of mucocutaneous junction, and a viscous meibomian gland secretion. Improvement was found after medical therapy for MGD. Therefore, it was concluded that the meibomian gland secretions contributed for the prevention of lacrimal outflow from the eyelid margin.

ABSTRACT NO.: 69

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Membrane-associated mucins on canine conjunctiva

Y. Umeda*,†, S. Nakamura‡, K. Fujiki†, H. Toshida†, A. Saito* and A. Murakami† *Triangle Animal Eye Clinic, †Department of Ophthalmology, Juntendo University School of Medicine, ‡Division of Biomedical Imaging Research, Biomedical Research Center, Juntendo University School of Medicine, Tokyo, Japan

Purpose:  One of the major components of the inner tear film layer is mucins. Based on sequence data, the mucins are divided into two categories of emerged-secreted mucins and membrane-associated mucins. Many of the membrane-associated mucins have a potential cleavage site in their extra cellular domain and are thought to be shed from the apical portion of epithelial cells as the soluble form of mucin. At least three membrane-associated mucins – MUC1, -4, and -16 – have been expressed in human corneal and conjunctival epithelia. The purpose of this study is to determine whether membrane-associated mucins are expressed on canine conjunctival epithelia.

Method:  Conjunctival tissues were dissected from normal dog. After making frozen sections of conjunctival, the conjunctival epithelium was dissected by laser captured microdissection and total RNA was isolated. Reverse transcription-polymerase chain reactions (RT-PCR) MUC1 and -4 were performed using the primers. The PCR products were electrophoresed on 1.5% agarose gel and stained with ethidium bromide.

Results:  RT-PCR analysis detected MUC1 and -4 mRNA in canine conjunctival epithelia.

Conclusions:  In this study, we found that membrane-associated mucins – MUC1 and -4 – are expressed in canine conjunctival epithelia. Further studies on expressions of MUC1, -4, and -16 will be useful to recognize their biological significance on the healthy canine ocular surface and in canine dry eye syndrome.

ABSTRACT NO.: 70

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Spontaneous lens capsule rupture in the canine cataract patients

H. Koyama, G. Takahashi, S. Watari, H. Sakoya, Y. Yokoyama, M. Tado, N. Tsuji, N. Kawagishi, T. Shin, M. Mukaino, T. Kochi, T. Bekki, T. Oji and M. Kawata NeoVets Osaka Veterinary Referral Center, Osaka, Japan

Purpose:  This study aims to describe the incidence and treatment of preoperative spontaneous lens capsule rupture in the canine cataract patients.

Methods:  A total of seven dogs (seven eyes) were presented for rapid progression of cataract. The patients included three American Cocker Spaniels, three Toy Poodles and one Miniature Schnauzer. Severe lens induced uveitis was seen in 6 of 7 eyes. The ultrasound examination revealed the reduced diameter of the lens and hyperechoic area behind the ciliary body in all cases. Such uveitis was unable to be controlled by medical treatment and surgery was performed in all eyes.

Results:  All patients underwent phacoemulsification. The white material behind the posterior lens capsule as well as the ruptured lens capsule was confirmed intraoperatively. The lens was stable and intraocular lens replacement was performed in all cases. The patients were on topical and oral anti-inflammatory medication for 4 months and 1–2 months, respectively. The material behind the lens disappeared within 2 months. Six of seven eyes had no complication after the surgery and retained vision. One of seven eyes was weak sighted due to high intraocular pressure.

Conclusion:  In cases of acute-onset cataract, lens capsule rupture may occur. Lens induced uveitis can also be seen frequently. The ultrasound examination is therefore highly recommended. As medical treatment for such uveitis is not very successful, early surgical intervention prior to secondary complication is favorable.

ABSTRACT NO.: 71

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Nucleotide sequencing for the mitochondrial transcription factor a gene (Tfam) in miniature schnauzer dogs affected with inherited retinal dysplasia and persistent hyperplastic primary vitreous

B. S. Bauer*, G. W. Forsyth†, L. S. Sandmeyer* and B. H. Grahn* *Department of Small Animal Clinical Studies and †Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SA, Canada

Purpose:  This study aims to determine if the Tfam gene sequence is altered in Miniature Schnauzer dogs affected with retinal dysplasia and persistent hyperplastic primary vitreous.

Methods:  Retina, retinal pigment epithelium, and whole blood samples were collected from affected and normal Miniature Schnauzer dogs. Total RNA was isolated from the retina and retinal pigment epithelium and reverse transcribed to make cDNA. White blood cell pellets were collected from the whole blood samples and genomic DNA was extracted. The Tfam coding sequence, 5′ promoter region, intron 1 and the 3′ noncoding sequence of normal and affected Miniature Schnauzer dogs were amplified using PCR, cloned and sequenced.

Results:  Sequencing of the coding, 5′ and 3′noncoding regions, and intron 1 of the Miniature Schnauzer Tfam gene revealed no significant base pair changes between affected and normal dogs.

Conclusions:  We failed to identify a mutation in the Tfam gene of Miniature Schnauzers affected with retinal dysplasia and persistent hyperplastic primary vitreous. Further investigations into other candidate genes or factors affecting Tfam transcription and/or mRNA stability in the retina and RPE of affected dogs is warranted.

Grant support:  Supported by the Companion Animal Health Fund.

ABSTRACT NO.: 72

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Ocular signs, aqueous humor protein, serological and structural changes of dogs (Canis familiaris) (Linnaeus, 1758), infected experimentally by the conjunctival route of exposure with Leishmania (Leishmania) chagasi (Cunha & Chagas, 1937)

J. Laus*, A. G. R. Melo* and L. C. Alves† *Faculty of Veterinary Medicine and Agricultural Sciences, Sao Paulo State University, Jaboticabal, Brazil; †Faculty of Veterinary, UFRPE, Recife, Pernambuco, Brazil

Purpose:  The aim of this study was to evaluate ocular changes, aqueous humor protein, and serological and structural changes of dogs infected experimentally by the conjunctival route of exposure with Leishmania (Leishmania) chagasi.

Methods:  A total of 10 healthy dogs were given a clinical examination, serum was assayed by ELISA for anti-Leishmania sp. antibodies, and bone marrow smears were examined cytologically. Two groups of dogs were studied. The first, inoculated group consisted of seven animals which received 150 µL of Leishmania (Leishmania) chagasi suspension by the conjunctival route and the control group consisted of three animals inoculated with saline solution by the same route. Ocular examinations were performed at 2, 4, 6, 12, and 24 h postinnoculation. After this period, they were monitored once daily for the first week and then once weekly until 60 days were completed. Blood samples, aqueous humor of both eyes, and bone marrow smears were collected at day 60 for serology, aqueous humor protein analyses, and parasitological examination.

Results:  All animals from inoculated group showed unilateral or bilateral ocular signs, particularly corneal opacification. Results of anti-Leishmania sp. antibodies titers in sera and aqueous humor, as well as parasitological examinations were negative. The histopathologic evaluation of eyes in the Leishmania-infected dogs revealed inflammatory response characterized by macrophage infiltration, lymphocytes, and plasma cells particularly on the third eyelid, the conjunctival tissue and the lacrimal gland. Edema, congestion, and a diffuse perivasculitis involving the uveal tract were also observed.

Conclusions:  The conjunctival route can be used as a model for the study of the pathogenesis of the canine ocular leishmaniasis; quantitation of IgG antibodies on sera must be done 2 months after topical experimental infection; the hallmark of topical ocular experimental infection is a nonspecific response with mononuclear cells.

Grant support:  Supported by FAPESP. 2006/53536–1.

ABSTRACT NO.: 73

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Histopathological and immunohistochemical alterations in the eyes of dogs infected with Leishmania chagasi

J. L. Laus*, F. L. C. Brito†, W. L. Tafuri‡, M. M. Figueiredo‡, V. A. Silva Júnior†, F. C. L. Maia† and L. C. Alves† *Faculty of Veterinary Medicine and Agricultural Sciences, Sao Paulo State University, Jaboticabal; †Rural Federal University of Pernambuco, UAG, Brazil; ‡Federal University of Minas Gerais, ICB, Brazil

Purpose:  The objective of the present study was to investigate the histopathological and immunohistochemical alterations that occur in the eyes of dogs naturally infected with Leishmania chagasi.

Methods:  The eyes of 25 dogs with a positive parasitological and serological exam for L. chagasi were submitted to routine ophthalmic examination. Fragments were obtained from the third eyelid, third eyelid gland, conjunctiva, fibrous, vascular and nervous tunic and optic nerve and were analyzed by immunohistochemistry and histopathology.

Results:  Ana lysis of the frequency of immunostaining for L. chagasi amastigotes in the two eyes showed that the conjunctiva of the third eyelid and the third eyelid gland were the most affected tissues, followed by the tunica fibrosa and anterior uvea. No immunostaining was observed in the optic nerve, retina, or choroid. Histopathological analysis revealed a predominantly mononuclear inflammatory infiltrate (lymphocytes and plasma cells) whose intensity ranged from discrete to intense in the various ocular structures. Vascular congestion and perivasculitis were also observed. Analysis of the correlation between inflammation and the presence of parasites in the ocular structures using Spearman's correlation coefficient revealed a significant correlation for the tunica fibrosa (R = 0.760609), third eyelid (R = 0.958403), and anterior uvea (R = 0.766652). However, no correlation was observed for the choroid (R = 0) or retina (R = 0).

Conclusions:  The histopathological alterations that occur in the eyeball of dogs with visceral leishmaniasis might be related to the presence of antibodies.

Grant support:  Supported by FAPESP 04/11718–0 and CNPq.

ABSTRACT NO.: 74

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Effects of carprofen administered by different routes to control experimental uveitis in dogs

J. L. Laus*, A. P. Ribeiro*, A. Escobar*, G. S. Godoy†, M. A. N. Costa‡, V. M. M. Cipólli* and C. S. Massamitsu* *Faculty of Veterinary Medicine and Agricultural Sciences, Sao Paulo State University, Jaboticabal, Brazil; †Espécialité, Veterinary Diagnostic Laboratory, ‡Diplomate in Medicine

Purpose:  This study aims to evaluate and compare the effects of carprofen (Rimadyl solução injetável, Pfizer, Guarulhos, Brazil) by the subconjunctival, topical, and subcutaneous routes in dogs with experimentally induced uveitits.

Methods:  All dogs received ophthalmic examinations prior to paracentesis to verify the absence of ocular lesions. Twenty dogs underwent general anesthesia and limbal aqueocentesis of the OD was accomplished, withdrawing 0.2 mL of aqueous (M0) to induce uveitits. Five hours after, a second aqueocentesis was performed (M1). Aqueous samples were frozen at −70 °C. Protein quantitation was performed with a commercial chemistry analyzer, and PGE2 quantitation was performed using ACE competitive enzyme immunoassay. Four groups were formed (n = 5), which received carprofen at the end of M1 by the following routes: subcutaneous (4.4 mg/kg) (GI), subconjunctival (2.2 mg/kg) (GII), and topical (parenteral solution diluted at 0.3%, hourly, until M1) (GIII). A control group (CG) was instituted and received no treatment. Bulbar conjunctiva of the animals of GII were biopsied for histopatological evaluation. Statistical analysis was performed using anova, and Pearson's test was used in order to verify correlation among protein and PGE2 values (P = 0.05).

Results:  Average protein values measured (mg/dL) at M0 and M1 were, respectively, 14.61 ± 1.65 and 218.31 ± 63.14 (GI); 11.37 ± 2.28 and 295.00 ± 76.17 (GII); 14.76 ± 2.11 and 176.43 ± 73.56 (GIII); and 10.25 ± 2.35 and 314.32 ± 62.06 (CG). PGE2 (pg/mL ± EPM) levels at M0 measured below the limit of the assay (15.0 pg/mL). At M1, PGE2 was, respectively, 911.29 ± 88.70 (GI), 775.80 ± 224.19 (GII), 807.07 ± 192.92 (GIII), and 814.95 ± 185.95 (CG). Significant increased values of protein and PGE2 were observed in M1 (P < 0001). At M1, values of protein and PGE2 did not change significantly among groups (P > 0.05). Protein and PGE2 levels correlated in GI (r2 = 0.61; P = 0012), and in GIII (r2 = 0.44; P = 0.049). Under the conjunctiva of the animals of GII, histopathologic evaluation showed exudative acute inflammation and mild hemorrhage.

Conclusions:  Carpofen was unable to inhibit the synthesis of PGE2 and the protein influx to the anterior chamber, after paracentesis induced uveitis in dogs. The reduction of 44% (topical) in protein levels, suggests that by this route, the agent can be used as an adjuvant to control uveitis in dogs.

Grant support:  Supported by Fundação de Amparo à Pesquisa do Estado de São Paulo–FAPESP (protocol no. 05/60023–8) and CNPq.

ABSTRACT NO.: 75

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Effect of the ethyl-cyanoacrylate or the octhyl-cyanoacrylate in experimental corneal lesions in rabbits

J. L. Laus, V. T. Barbosa, A. P. Ribeiro, B. C. Martins, R. Thiesen, M. A. G. Silva, V. C. Musci, A. L. G. Souza and M. R. F. Machado Faculty of Veterinary Medicine and Agricultural Sciences, Sao Paulo State University, Jaboticabal, Brazil

Purpose:  This study aims to compare the effects of two cyanoacrylates in rabbit corneas after lamellar keratectomy.

Methods:  Ethyl-cyanoacrylate and octhyl-cyanoacrylate were clinically and histopathologic compared in corneas of 36 rabbits after lamellar keratectomy of 3 mm of diameter and 0.5 mm of depth. The adhesives were applied and covered with a fine film of cellulose. In the postoperative period, ophthalmic (days 0, 1, 3, 5, 7, 14, 21, 30, 44, and 60) and hystopathologic exams (periods 3, 7, 14, 21, 30, and 60) were performed. There was used a factorial array of 2 treatments × 6 periods with 3 repetitions. Continuous variables were analyzed by the least-squares method. Discrete variables were transformed and compared by the chi-squared test.

Results:  Clinically, there were significant differences for the variables of water consumption, attitude, blepharitis, corneal edema, fluorescein test, and adhesive permanence time. The mean permanence time for the ethyl-cyanoacrylate was 7,66 days and for the octhyl-cyanoacrylate was 17,22 days. With respect to the histopathological evaluation, for the treatment with ethyl-cyanoacrylate, there was moderate inflammatory reaction in the initial phases. There was no complication during corneal epitelization and collagen organization. For the octhyl-cyanoacrylate, there adhesive permanence was not observed until later phases. Reepithelization and collagen organization occurred with a discrete inflammatory reaction.

Conclusions:  Under the clinical and histopatologic points the results had shown advantages to the octhyl-cyanoacrylate.

Grant support:  Supported by FAPESP 2005/59086–5.

ABSTRACT NO.: 76

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Canine lens instability surgical options. Part 2: a modified ab-externo approach for suture fixation of an intraocular lens implant in the dog

D. A. Wilkie, S. G. Stone, A. J. Gemensky-Metzler, C. R. Basham and K. N. Norris College of Veterinary Medicine, Ohio State University, Columbus, OH, USA

Purpose:  The purpose of this study is to evaluate a modified ab-externo approach for intraocular lens (IOL) placement in instances of complete lens instability.

Methods:  Four dogs presented for unilateral phacoemulsification of early immature to hypermature cataracts. Lens instability of greater than 180 degrees to complete zonular instability was discovered preoperatively or intraoperatively. Lenses were removed by either phacoemulsification or ICLE. A PMMA IOL (K9400 Ocularvison, CA, USA) was implanted following lens extraction. The IOL was implanted using a modified ab-externo technique and 2 or 3 point fixation with 9–0 nylon. In one eye, endolaser cyclophotoablation was performed at the time of IOL implantation.

Results:  Mild intravitreal bleeding was observed in 2/4 eyes. Lens centration was considered good to excellent in 3/4 eyes and the IOL was tipped slightly in 1/4 eyes. All eyes remain sighted at the most recent examination (2–24 months). Intraocular pressure remains within normal limits in all eyes.

Conclusion:  The advantages of the modified ab-externo technique are that it allows placement of all sutures through a 3.2-mm incision, the globe and anterior chamber are maintained and the surgeon has excellent visualization of the suture and needles throughout the procedure. Suture placement is more accurate and far less traumatic than with the conventional ab-interno approach. Therefore, complications such as intraoperative hemorrhage and IOL decentration may be avoided. In addition, with a newly designed foldable suture IOL (Acri.Tec 10 V-17) the IOL can be implanted through a 4-mm incision. This technique may allow the veterinary ophthalmic surgeon to consider early intervention in eyes with lens instability and to restore emmetropia in eyes that would previously have remained aphakic.

Grant support:  Supported in part by Acri.Tec®.

ABSTRACT NO.: 77

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Scanning electron microscope observations of the corneal endothelium in the red-eared turtle (Trachemys scripta)

J. A. T. Pigatto*, C. P. Schneider†, M. C. Andrade*, S. T. Oliveira*, R. Stedile*, G. M. Rigon*, P. S. Hünning* and J. L. Laus‡ *School of Veterinary Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Brazil; †School of Medicine, University of Passo Fundo, Passo Fundo, Brazil; ‡School of Veterinary Medicine, Sao Paulo State University, Jaboticabal, Brazil

Purpose:  Although there have been many studies of the corneal endothelium of human and some mammals, there have been few in others vertebrates. The aim of this study was to examine the surface morphology in red-eared turtle.

Methods:  Two corneas from one young red-eared turtle (Trachemyis scripta) were used. All procedures were performed in compliance with ARVO statement for use of animals in ophthalmic and vision research. Eyes were prepared immediately postmortem for scanning electron microscopy. Ten photomicrographs of the central at ×750 magnification were obtained from each cornea using scanning electron microscope. The morphometric analysis was performed with regard to polygonality, mean cell area, and cell density. Statistical analysis was conducted using the Tukey test. Values of P < 0.05% were considered significant.

Results:  Scanning electron microscopy revealed corneal endothelium characterized by a continuous layer composed of polygonal cells uniform in size and shape. The predominant number of cells was hexagonal (55%) in shape, with pentagonal (35%) and heptagonal cells (9%) constituting the greater portion of the remaining corneal endothelium. The mean cell area was 332 ± 71 µm2 and cell density was 3012 ± 154 cells per mm2. Statistical analysis showed that the comparison between right and left eye did not exhibit differences in the variables determined.

Conclusion:  The structure of the corneal endothelium of red-eared turtle is similar to those described for other vertebrates.

ABSTRACT NO.: 78

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Morphological analysis of the corneal endothelial cells of chinchilla (Chinchilla lanigera) using scanning electron microscopy

J. A. T. Pigatto*, C. P. Schneider†, A. C. P. Araujo*, A. Sartori*, A. C. R. Almeida*, G. M. Rigon*, P. S. Hünning* and J. L. Laus‡ *School of Veterinary Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Brazil; †School of Medicine, University of Passo Fundo, Passo Fundo, Brazil; ‡School of Veterinary Medicine, Sao Paulo State University, Jaboticabal, Brazil

Purpose:  Although there have been many studies of the corneal endothelium of human and some mammals, there have been few in others vertebrates. The aim of this study was to examine the surface morphology and to perform morphological analysis of the corneal endothelial cells of chinchilla.

Methods:  Twenty-four corneas from 12 1-year-old chinchilla (Chinchilla lanigera) were used. All procedures were performed in compliance with ARVO statement for use of animals in ophthalmic and vision research. Eyes were prepared immediately postmortem for scanning electron microscopy. Ten photomicrographs of the central corneal endothelium at ×750 magnification were obtained from each cornea using scanning electron microscope. The morphological analysis was performed. Statistical analysis was conducted using the Tukey test. Values of P < 0.05% were considered significant.

Results:  Scanning electron microscopy revealed corneal endothelium characterized by a continuous layer composed of polygonal cells uniform in size and shape. The predominant number of cells was hexagonal (72%) in shape, with pentagonal (16%) and heptagonal cells (12%) constituting the greater portion of the remaining corneal endothelium. Statistical analysis showed that the comparison between right and left eye did not exhibit differences in the variables determined.

Conclusion:  The morphology of the corneal endothelium of chinchilla is similar to those described for other vertebrates.

ABSTRACT NO.: 79

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Effects of glaucoma on the canine corneal endothelium: a scanning electron microscopy study

J. A. T. Pigatto*, C. P. Schneider†, G. M. Rigon*, L. Albuquerque*, P. S. Hünning* and J. L. Laus‡ *School of Veterinary Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Brazil; †School of Medicine, University of Passo Fundo, Passo Fundo, Brazil; ‡School of Veterinary Medicine, Sao Paulo State University, Jaboticabal, Brazil

Purpose:  This study aims to evaluate the effects of glaucoma on the canine corneal endothelial cells using scanning electron microscopy.

Methods:  Twelve adult dogs referred to the Veterinary Ophthalmology Section of the Federal University of Rio Grande do Sul which the glaucoma deteriorated to blindness were enucleated. This study was in accordance with the ARVO statement for use of animals in ophthalmic and vision research. Immediately after enucleation the corneal endothelium of these eyes was studied by scanning electron microscopy. The posterior endothelial surface was examined and photographed using a scanning electron microscope. Ten photomicrographs of the corneal endothelium were obtained from each cornea.

Results: In all samples surveyed by scanning electron microscopy, endothelial lesions were seen randomly distributed over the entire cornea. Many areas showed cells with severe rupture. With increasing damage the cells appeared condensed, and as a consequence their nuclei protruded into the anterior chamber. The endothelial cells had few microvilli on their surface.

Conclusion:  The results of this study show that the morphological damage is responsible for the resultant corneal edema.

ABSTRACT NO.: 80

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Computed tomography, optical coherence tomography, scanning laser ophthalmoscopy correlation to gross and histologic exam of the eyes of pigs and rabbits

J. S. Estep* and C. D. DiCarlo† *United States Army Institute of Surgical Research, †South-west Foundation for Biomedical Research

Purpose:  This study aims to establish baseline computed tomography (CT) and optical coherence tomography (OCT)/scanning laser ophthalmoscopy (SLO) images from swine and rabbits, and correlate images to gross and histologic examinations of normal swine and rabbit ocular tissues. The US Army Institute of Surgical Research Combat Casualty Care animal models are vital for advancing trauma research. Five percent of all injuries, from the current military conflicts, include significant eye injuries. Unlike trauma in the civilian sector, eye injuries in military settings tend to be caused by explosive devices, This often results in multiple foreign bodies and simultaneous injuries to other body systems. Thus, the military has a need for the development of an eye injury model.

Methods:  This descriptive study was conducted on animals that were shared with other studies: 14 Yorkshire cross pigs, 12 Yucatan miniature pigs, and 8 rabbits. A full-body 16 slice CT exam (all 34 animals) and OCT/SLO scan (2 animals from each group) were performed. The OCT/SLO is a computerized optical scanner device that provides high-resolution/high-definition images of the surface anatomy of the fundus using a combination of confocal imaging as well as high-resolution tomographic images of subsurface tissue structure. This system can produce both en-face (C-Scan) as well as cross-sectional (B-Scan) OCT images. At the termination of the study, a full necropsy was performed to include both gross exam and a complete histologic exam of all tissues.

Results:  CT scans of the head demonstrated excellent detail of the orbital bone, muscle, fat, orbit, lens, and ocular nerves. The size, shape, and symmetry of these tissues were assessed and were consistent with the necropsy findings. OCT/SLO images of the retina and optic disc were challenging to obtain from pigs due to the system optics but were easily obtained from rabbits. There was a direct correlation of the retinal images to the histologic sections of the retina.

Conclusions:  Swine and rabbits are ideal models for human ocular trauma due to the size of the globe, similar thickness of the ocular tissues, and for their established use as models of human trauma research. Histologic evaluation of eyes and bony orbits from rabbits and pigs imaged with CT and OCT/SLO provides a good correlation between the in vivo ocular state and the post mortem histopathology. This baseline study is necessary for comparison to future ocular injury research projects.

ABSTRACT NO.: 81

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Teratiod meduloepithelioma in a domestic shorthaired cat: a case report

J. S. Estep* and T. Evans† *United States Army Institute of Surgical Research, †Mammal Eye Clinic

Purpose:  This study aims to describe a case of teratoid medulloepithelioma in a kitten.

Methods:  A 4-month-old stray kitten with multiple ocular anomalies was referred to the Eye Center for Animals. The kitten had upper lateral eyelid colobomas OU, microphthalmous/phthisis and KCS OS, and anterior segment dysgenesis OD. Using a retinographics unit, a single flash electroretinogram (FERG) was performed on both eyes after 12 min of dark adaptation. The FERG was flat-lined in the left eye and within normal limits in the right eye. Enucleation was chosen OS, as this eye was blind and the owner wanted no problems with the eye in the future. The coloboma of the upper right lid was repaired with an upper lid transplant/free graft (using lid from the left eye). The enucleation was uneventful. The enucleated left eye was fixed in formaldehyde 10% and submitted for histopathology.

Results:  Histology of the left eye revealed a tumor that arising from the ciliary body and adhered to retina, and a degenerated remnant of lens. The mass was composed of multiple elements. The elements include cuboidal to spindle shaped epithelial cells arranged in irregularly shaped tubular structures and small rosettes, and well-differentiated bone and cartilage. The mitotic rate was low and no anaplasia was observed. The epithelial and heterotopic components and location of the mass, and age of the kitten were consistent with teratoid medulloepithelioma. The right eye healed normally with minimal scaring. Sixteen months after enucleation the cat has shown no sign of reoccurrence or malignant spread of this tumor.

Conclusions:  Medulloepithelioma is a rare tumor in both animals and humans and has only been reported once in the domestic cat. Teratoid medulloepithelioma is one variant of this tumor and has never been reported in cats. These tumors originate from the primitive neuroectoderm of the optic cup and can arise from retina, ciliary epithelium, vitreous body, or neuroglia. Teratoid medulloepitheliomas are characterized by the presence of tissues that are not normally present in the eye (i.e. bone, cartilage, brain, muscle, and primitive mesenchyme).

ABSTRACT NO.: 82

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Ocular toxicity of subconjunctival and intravitreal rapamycin in horses

L. C. Douglas, J. H. Salmon, N. Y. Yi and B. C. Gilger Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA

Purpose:  Equine recurrent uveitis (ERU), a T-cell-mediated disease, is the most common cause of blindness in horses. The purpose of this study was to determine the ocular toxicity of subconjunctival and intravitreal rapamycin (RAPA), a potent T-cell inhibitor and possible treatment for ERU, in normal horses.

Methods:  Six normal adult horses received in the right eye either 5 mg or 10 mg of RAPA intravitreally or 10 mg of RAPA (in 1 mL PEG 400) subconjunctivally. The left eye of each horse received 1 mL subconjunctival or intravitreal PEG 400. Complete ophthalmic exams (direct ophthalmoscopy, biomicroscopy, tonometry, scotopic and photopic electroretinography (ERG), and fundic photography) were performed on all horses preinjection and on days 1, 7, 14, and 21 after injection. Complete blood count (CBC) and serum chemistry were performed preinjection and pre-euthanasia. Horses were euthanized 7 or 21 days after injection. All eyes were enucleated, samples were collected for RAPA fluid and tissue concentrations, and eyes were submitted for histopathologic examination.

Results:  At injection, one horse had subconjunctival hemorrhage and one horse had mild vitreal hemorrhage, noted immediately after injection. No evidence of intraocular inflammation was noted in either eye at any examination day after injection, except for the horse with vitreal hemorrhage, which had moderate vitreal fibrin formation and periocular swelling at day 1 after injection; signs diminished by day 7. All horses had visible vitreal crystals. No evidence of retinal changes was noted on clinical examination. No significant differences were noted on ERG parameters when comparing the right and left eyes prior to injection to parameters after injection. No abnormalities were noted on histopathology, CBC, or serum chemistry.

Conclusions:  Based on this study, there was no evidence of ocular irritation or toxicity of up to 10 mg of RAPA in PEG 400 injected intravitreally or subconjunctivally into the normal equine eye, although intravitreal injection was associated with transient inflammation. Further study is needed to determine the best route, dose, and efficacy of RAPA in horses with immune-mediated ocular disease.

Grant support:  Supported by the Merck-Merial Veterinary Scholars Research Foundation, NC Equine Uveitis Research Fund, State of North Carolina.

ABSTRACT NO.: 83

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Ocular effects following aqueocentesis in dogs using variable needle sizes: fluorophotometric and tonometric evaluation

R. A. Allbaugh and H. D. Davidson Kansas State University College of Veterinary Medicine, Manhattan, KS, USA

Purpose:  Aqueous paracentesis is a common procedure for both therapeutic and diagnostic purposes. This procedure results in breakdown of the blood–aqueous barrier and has been used as a model for intraocular inflammation. One purpose of this study was to use fluorophotometry to evaluate the degree of breakdown following aqueocentesis using variable needle sizes. The second purpose was to track the intraocular pressure (IOP) response.

Methods:  Twenty-four healthy, adult beagles were divided into three equal groups. In each dog the treated eye (25-, 27-, or 30-gauge needle) was determined randomly, the contralateral eye was the control. Aqueocentesis at the lateral limbus was performed under sedation and topical anesthesia. Fluorophotometry was performed before and after aqueocentesis on day 1. Days 2–5 sedation and fluorophotometry were repeated. IOP was measured with a rebound tonometer at multiple time points.

Results:  There was no statistical difference in fluorescein concentration or IOP between 27- and 30-gauge needles. Use of 25-gauge needle resulted in a statistically significant increase (P < 0.05) in anterior chamber fluorescence on days 3 and 5. It also caused a statistically significant increase in intraocular pressure at 20 min postaqueocentesis as compared to the 27- and 30-gauge needles. High variability and large standard deviations were found to be a problem.

Conclusions:  Statistical significance was limited in this study; however, 25-gauge needle aqueocentesis did result in a greater degree of blood–aqueous barrier breakdown and a rapid state of intraocular hypertension postparacentesis.

Grant support:  Supported by Kansas State University College of Veterinary Medicine Intramural Grant.

ABSTRACT NO.: 84

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Influence of lens design and material on capsular opacification and refractive status after phacoemulsification cataract removal and replacement intraocular lens implantation in dogs

B. W. Gift*, R. V. English*, B. Nadelstein*, A. Weigt* and B. C. Gilger† *Animal Eye Care, Cary, NC, †Department of Clinical Sciences, North Carolina State University, Raleigh, NC, USA

Purpose:  This study aims to evaluate the effect of three types of lens design and biomaterial on resultant posterior capsular opacification and refractive correction.

Methods:  Sixty client-owned dogs undergoing bilateral phacoemulsification for mature or diabetic cataracts were prospectively included in the study. One randomly selected eye received a 41 D polymethyl-methacrylate (PMMA) intraocular replacement lens (IOL) and the contralateral eye received either a 41 D hydrophilic acrylic IOL (n = 35) or a 40 D hydrophobic acrylic IOL (n = 25). At the (mean = 82 days) follow-up exam, posterior capsular opacification (PCO) was graded using direct slit lamp observation and by evaluation of digital exterior and retroillumination images of the lenses. The images were cropped to reveal the center 6 mm of the lens and capsule eliminating the ability to determine the type of lens and graded by four observers. Streak retinoscopy was used to measure refractive status. B-mode ultrasonography was used to calculate center of the IOL to retinal surface distance to measure relative lens position between the different lens types. These results were analyzed both within a patient (PMMA-Acrylic) and across groups. Statistical analyses were performed via one-way anova with Tukey–Kramer test for multiple comparisons and with the student's t-test (PMMA-Acrylic). P-values of < 0.05 were considered significant.

Results:  The PCO score by direct biomicroscopic evaluation was significantly lower for the hydrophilic acrylic lens (mean 0.542) when compared to the PMMA (mean 0.85); however, no significant difference was noted when either of these lenses were compared with the hydrophobic acrylic lens (mean 0.64). Grading of digital images showed that the PMMA IOL had significantly greater PCO than the hydrophobic acrylic lens. Streak retinoscopy showed that the PMMA IOL was significantly closer to emmetropia (mean of +0.44 D) when compared to either the hydrophilic acrylic (mean of +0.96 D) or the hydrophobic acrylic (mean of +1.2 D). The distance from the center of the lens to the retina was significantly less for the hydrophilic acrylic lens (mean 0.36 mm closer to the retina) and significantly greater for the hydrophobic lenses (mean 0.60 mm further from the retina) when compared to the PMMA lenses.

Conclusion:  Acrylic lenses have the potential to provide clear visual axis but both lenses tested resulted in greater persistent hyperopia than the PMMA lens evaluated.

ABSTRACT NO.: 85

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Retrospective study of intracapsular lens extraction in the dog

C. B. Breaux*, S. J. Dugan*, A. M. Siegel* and T. Schreiner† *Department of Veterinary Clinical Medicine, University of Illinois, Urbana, IL; †Eye Specialists for Animals, Denver, CO, USA

Purpose:  This study aims to determine the incidence and risk factors of postoperative complications following intracapsular lens extraction in dogs.

Methods:  Medical records from dogs undergoing intracapsular lens extraction by a single surgeon from 1993 to 2006 were reviewed. Signalment, preoperative examination results, surgical complications, and serial postoperative examination results were recorded for up to 5 years when available. The cause and date of failure were recorded for cases that were nonvisual postoperatively.

Results:  One hundred and fifty-six eyes of 106 dogs were included. The average age at presentation was 9 years (range 2–15). Fifty-seven dogs (54%) were affected bilaterally. The average follow-up time for all dogs in the study was 619 days. Mixed breeds (23 dogs) were most commonly affected followed by Jack Russell Terrier (17), Poodle (14), Cocker Spaniel (10), and Boston Terrier (7). Forty-three eyes (28%) were blind due to glaucoma at an average of 285 days (range 0–2541) postoperatively. Nineteen eyes (12%) were blind due to retinal detachment at an average date of 209 days (range 0–1289) postoperatively. Fifteen eyes (10%) were blind due to other causes at an average of 167 days (range 0–1123) postoperatively. Forty-seven eyes (30%) were not returned for scheduled reevaluations, 39 of which were visual at the last examination with an average follow-up time of 151 days (90–1745). Thirty-two dogs (21%) were visual at their current examination or at that time of death of unrelated causes with an average follow up time of 566 days (40–1409).

Conclusions:  Terrier breeds are commonly affected by lens luxation, but there may be additional predisposed breeds. Glaucoma and retinal detachment are the most common complications following ICLE surgery. Diligent follow-up and monitoring of intraocular pressure trends are critical for maintenance of vision. Prophylactic retinopexy may be beneficial in dogs undergoing ICLE surgery.

ABSTRACT NO.: 86

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Transcleral vitrectomy for the diagnosis of Leptospira and treatment of equine recurrent uveitis in a horse in the United States

E. S. Storey*, H. Gerhards† and B. Wollanke† *School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA; †Clinic for Horses, Ludwig Maximilians University, Munich, Germany

Purpose:  This study aims to determine if (i) Leptospira sp. may be detected in the vitreous from a horse affected with equine recurrent uveitis (ERU) in the United States and (ii) transcleral vitrectomy results in clinical improvement of a horse affected with ERU originating in the United States.

Methods:  A warmblood mare with a chronic ERU was treated with topical and subconjunctival corticosteroids to minimize inflammation. Serum was obtained for antibody titers to Leptospira sp. serovars. A two-port vitrectomy was completed as previously described by the authors (H.G. and B.W.). Briefly, carbon dioxide laser was used to create transcleral ports, vitreous was collected for Leptospira antibody titers, PCR, and culture, vitrectomy of the vitreous core and base was completed, scleral incisions were closed, and gentamycin was injected subconjunctivally. Treatment with topical corticosteroids was continued until the postoperative inflammation subsided. Topical medications were discontinued by 8 weeks postoperatively. Clinical reevaluations were completed repeatedly for 8 months postoperatively.

Results:  Serum and vitreous antibody titers, vitreous PCR, and vitreous culture were positive for Leptospira serovar pomona. The eye improved significantly postoperatively. Inflammation no longer persisted despite tapering and cessation of topical corticosteroids. Yellow discoloration, cloudiness, and opacification of the vitreous resolved postoperatively. Peripapillary retinal folds, progressing acutely preoperatively, have not progressed.

Conclusions:  Horses born and raised in the United States may have a Leptospira sp. vitreous infection associated with ERU and transcleral vitrectomy may significantly improve the diagnosis and treatment of ERU in these horses.

ABSTRACT NO.: 87

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Tear film analysis of Orcinus orca

Carmen Colitz*,†, Richard J. Sessler‡, B. Kari‡,Green-Church‡, Michael S. Renner§, M. M. Rodriguez§, Heather L. Chandler*, Kimberly Newkirk*, Kelly K. Nichols* and Jason J. Nichols‡ *Ohio State University College of Veterinary Medicine, Columbus OH; †Animal Eye Specialty Clinic, West Palm Beach, FL; ‡Ohio State University College of Optometry, Columbus, OH; §Miami Seaquarium, Miami, FL, USA

Purpose:  The tear film layer of the Orca whale is viscous compared to land mammals, suggesting the mucin layer may predominate. There is concern that topical therapy with medications can penetrate this thick viscous Orca tears and enter the cornea or anterior chamber. Thus, the purpose of this work was to evaluate cetacean tear film using mass spectrometry based methods.

Methods:  A 1-mL tear film sample from an Orca whale was analyzed by 1D SDS-PAGE and Comassie staining, then, an entire gel lane was divided into 40 sections and digested. Peptides were extracted from the bands after digestion and analyzed by LC-MS/MS. Sequence information from the MS/MS data were processed using MASCOT.

Results:  Proteins identified included lysozyme, submaxillary apomucin, immunoglobulin V(H), immunoglobulin J chain, immunoglobulin A heavy chain, MUC19, protein similar to mucin 19, immunoglobulin M heavy chain, solute carrier family 25 member 36, albumin, complement C3 precursor.

Discussion:  This is notably different from what is commonly observed in human tear film especially the high amounts of mucins. In cetaceans, the mucin layer appears to be much more substantial, and may function as a barrier at the eye/water interface. This may have clinical implications relative to the use of topical medications ability penetrate the mucins. One approach would be the addition of mucolytics (e.g. acetyl-cysteine) to existing medications to improve the effectiveness of topical medications for these animals. Alternatively, oral medications may be a more effective way to treat ophthalmic problems of cetaceans.