LAUSR

PURPOSE To evaluate the IOP values obtained from normal canine eyes, by means of the TonoVet Plus (TVP) and TonoPen Avia (TPA), and compare them to an established tonometer, the TonoVet (TV). METHODS Tonometry was performed bilaterally in 50 healthy dogs, age 1-11 years. The rebound tonometers (TV and TVP) were used first (in a random order), and then, one drop of tetracaine hydrochloride was applied to each eye, and approximately one minute later the IOP was estimated using the TPA. The mean ± standard deviation (SD) was calculated for each tonometer and a paired Student's t test was used to compare the IOP values between tonometers. A P value ≤ .05 was considered significant. The agreement between tonometers was assessed by a Bland-Altman plot. RESULTS The mean ± SD (range) IOP values were 15.0 ± 3.2 mm Hg (7-22), 19.2 ± 3.1 mm Hg (11-25), and 12.8 ± 2.9 mm Hg (6-19), for the TV, TVP, and TPA, respectively. The IOP values obtained by each tonometer were significantly different compared to the other two (P < .0001). There was a good agreement with fixed bias between all tonometers. CONCLUSIONS The average IOP values of the TVP were significantly higher than those of the TV, which were significantly higher than those of the TPA, in normal canine eyes. Knowing the normal IOP values for these tonometers and the bias between them will help the clinician with the interpretation of IOP values obtained by these devices and compare between them.