Estimation of intraocular pressure in rabbits using noncontact tonometer: a comparative evaluation with Schiotz tonometer.

Estimation of intraocular pressure in rabbits is often done by indentation tonometry using Schiotz tonometer. The use of Schiotz tonometer for estimation of intraocular pressure requires the use of topical anesthesia, poses risk of infection and injury to cornea and puts the animal under stress. Therefore, in this study noncontact tonometer was used to estimate intraocular pressure in rabbits and the technique is described for the first time. Twenty-five rabbits were subjected to intraocular pressure estimation using Schiotz as well as noncontact tonometer by two independent observers. All intraobserver and interobserver differences were within two standard deviation from the mean, indicating good repeatability and reproducibility of the two methods. A good linear correlation was observed between measurements done by Schiotz and noncontact tonometers with the correlation coefficient (r(2)) of 0.9122 and regression equation y = 1.632x + 4.8684. No significant difference was observed in percent change in intraocular pressure in timolol-treated, water-loaded rabbits using noncontact tonometer and Schiotz tonometer. Noncontact tonometer provides an easy, quick and safe method for intraocular pressure estimation, which is comparable to the conventional method of Schiotz tonometry. Therefore, despite the cost, noncontact tonometry seems to have a greater scope in experimental studies.