Equine glaucoma: a histopathologic retrospective study (1999–2012)
Article first published online: 16 JUL 2013
© 2013 American College of Veterinary Ophthalmologists
Volume 17, Issue 5, pages 334–342, September 2014
How to Cite
Curto, E. M., Gemensky-Metzler, A. J., Chandler, H. L. and Wilkie, D. A. (2014), Equine glaucoma: a histopathologic retrospective study (1999–2012). Veterinary Ophthalmology, 17: 334–342. doi: 10.1111/vop.12080
- Issue published online: 5 SEP 2014
- Article first published online: 16 JUL 2013
- intraocular hypertension;
To characterize and describe the histopathologic findings in equine globes enucleated due to glaucoma.
Medical records at The Ohio State University from 1999 to 2012 were reviewed retrospectively. Signalment, history, and treatment data were collected, and histologic slides of enucleated globes were examined and lesions recorded. Twenty-three eyes from 23 horses were eligible for inclusion in this study.
The majority of affected horses were > 15 years of age (65%). The ages ranged from 5 to 35 years (mean = 17.4 years). The left eye was affected in 10 cases (43%) and the right eye in 13 cases (57%). There were 13 mares (56%) and 10 geldings (44%). Quarter Horses (30%), Appaloosas (26%), and Thoroughbreds (22%) were the most common breeds in the study population. The most common histopathologic changes included hypercellularity of the optic nerve (93%), retinal atrophy (89%), corneal vascularization (83%), descemetization of pectinate ligaments (83%), hypercellularity of the anterior corneal stroma (75%), posterior bowing of the iris base (74%), ciliary body atrophy (74%), corneal striae (70%), pars plana elongation (60%), cataract (53%), and collapsed ciliary cleft/trabecular meshwork (52%). Evidence of uveitis (cataract, lymphoplasmacytic infiltration of the uvea, and/or anterior or posterior synechiae) was present in 20/23 eyes (87%).
Equine glaucoma most commonly occurs secondary to uveitis with Appaloosas and older horses predisposed. Histologic changes are comparable to prior reports of chronic glaucoma; notable findings not previously described in the horse were posterior bowing of the iris base and relative sparing of the superior retina from atrophy associated with elevated IOP.