Assessing intraocular pressure by rebound tonometer in rats with an air-filled anterior chamber

Abstract

PURPOSE: To compare rebound tonometer and cannulation as methods for measuring intraocular pressure (IOP) in rats. METHODS: The accuracy of the TonoLab rebound tonometer was determined in eight cannulated rat eyes. IOP was manipulated by changing air pressure from 20 to 100 mmHg at 10-mmHg intervals, and the IOP was measured with the rebound tonometer at each level. The average value of three repeated pressure readings was recorded. Correlation analysis and comparison with the Bland and Altman method were performed. The intraclass correlation coefficient was calculated to assess intraoperator variability. RESULTS: The IOP values measured with the TonoLab rebound tonometer were well correlated with the actual IOP (r (2) = 0.963, P = 0.01). The mean of the difference between the rebound tonometer and actual (cannulation) IOP was 7.41 +/- 7.87%. The intraclass correlation coefficient was 0.9, indicating low intraoperator variability. CONCLUSIONS: The rebound tonometer showed high accuracy and reliability for IOP measurement in rat eyes.