Comparison of the rebound tonometer (ICare®) to the applanation tonometer (Tonopen XL®) in normotensive dogs

Authors

  • M. Leiva,

    1. Departament de Medicina i Cirurgia Animal, Facultat de, Veterinaria, Edifici V, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, España
    Search for more papers by this author
  • C. Naranjo,

    1. Departament de Medicina i Cirurgia Animal, Facultat de, Veterinaria, Edifici V, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, España
    Search for more papers by this author
  • M. T. Peña

    1. Departament de Medicina i Cirurgia Animal, Facultat de, Veterinaria, Edifici V, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, España
    Search for more papers by this author

Address communications to: Marta Leiva Tel.: 0034 93 5811944 0034 93 5811894 Fax: 0034 93 5813428 e-mail: marta.leiva@uab.es

Abstract

Objective To compare intraocular pressure (IOP) measurements obtained by recently introduced rebound tonometer (ICare®) and the well-known applanation tonometer Tonopen XL® in normal canine eyes.

Methods In a prospective, randomized, single-center study, IOP measurements by ICare® and Tonopen XL® tonometers were compared in 160 nonpathologic canine eyes (80 dogs). Complete slit-lamp biomicroscopy and indirect ophthalmoscopy were performed on each dog. Rebound tonometry was performed first and immediately after topical anesthetic drops were instilled in both eyes. One minute after the application of the topical anesthetic, applanation tonometry was performed in both eyes. The intraocular pressures obtained by use of both techniques were compared by statistical analysis.

Results The mean IOP readings were 9.158 mmHg (SD 3.471 mmHg) for the ICare® tonometer (x) and 11.053 mmHg (SD 3.451 mmHg) for the Tonopen XL® readings (y). The mean difference in intraocular pressures (−1.905 mmHg) was within clinically acceptable limits. The correlation coefficient (r2) of the relationship within both tonometers was r2 = 0.7477. The corresponding linear regression between the tonometers readings was y = 0.6662x + 4.942.

Conclusions Intraocular pressures obtained with the ICare® rebound tonometer were concordant with the IOP readings obtained by applanation Tonopen XL®, but ICare® values were significantly (P < 0.0001) lower. Rebound tonometry could be an appropriate tonometry method for routine clinical use after its calibration for canine eyes.

Ancillary