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Estimation of intraocular pressure in rabbits with commonly used tonometers
Ana C Acosta1, Edgar M Espana, Izuru Nose
1Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, 1638 NW10th Avenue, Miami, FL 33136, USA.
Background And Objectives:
To validate accuracy and reproducibility of the Perkins tonometer, pneumatonometer, and Tono-Pen XL (Medtronic Solan, Jacksonville, FL) in estimating intraocular pressure (IOP) in rabbits.
Materials And Methods:
IOP was increased from 5 to 50 mm Hg in 5-mm increments. Measurements were compared to readings of two digital manometers simultaneously measuring real IOP in the anterior chamber and vitreous cavity. Interobserver accuracy was evaluated using 4 eyes with the Perkins tonometer.
Results:
The Perkins tonometer and Tono-Pen XL underestimated IOP and were more accurate at pressures less than 30 mm Hg. No statistically significant difference was found between real IOP and Tono-Pen XL readings. The pneumatonometer overestimated pressures in the low ranges but was accurate at pressures greater than 40 mm Hg. The Tono-Pen XL had more variability than the Perkins tonometer and pneumatonometer at high IOP.
Conclusions:
None of the tonometers are accurate or reproducible in estimating IOP in rabbits over the tested range. Pneumatonometry, although not very accurate, has the advantage of having acceptable variability.
