Suitability and calibration of a rebound tonometer to measure IOP in rabbit and pig eyes.

Abstract

OBJECTIVE: To utilize the Icare tonometer TAO1 for intraocular pressure (IOP) determination in experimental animals. To calculate true IOP calibration functions for rabbit and porcine eyes. ANIMALS: Enucleated eyes of 3-year-old healthy experimental rabbits (New Zealand white), and healthy 1 year old experimental pigs (Deutsche Landrasse) were used for the determination of IOP. PROCEDURES: Manometric (Geuder GmbH, Heidelberg/Germany) and rebound tonometry (Icare tonometer TAO1, Icare, Helsinki/Finland) were used to record IOP in enucleated animal eyes (rabbit n=2, pig n=3). RESULTS: The Icare tonometer TAO1 measurements underestimated true IOP by 37-60% in rabbit eyes and 17-63% in porcine eyes. IOP values obtained by both rebound and manometric tonometry for rabbit and porcine eyes followed a linear regression curve. Linear functions were calculated to correct the Icare tonometer TAO1 measurements to true IOP for both rabbit (p=1.4244p(ic) + 4.2421) and porcine eyes (p=1.0799p(ic) + 5.8557). CONCLUSIONS: The Icare tonometer TAO1 can be utilized for IOP determination in rabbit and porcine eyes when measured values are corrected with the appropriate linear function.