Validation of the eyeTelemed IOPvet indentation tonometer for use in dogs.

Abstract

OBJECTIVE: To assess the accuracy of canine intraocular pressure (IOP) estimates from the eyeTelemed IOPvet indentation tonometer. ANIMALS STUDIED: Part 1 included 54 eyes from 28 Beagle dogs-23 ADAMTS10-mutants with open-angle glaucoma and 5 normals. Part 2 involved five normal canine ex&#xa0;vivo globes. PROCEDURE: Part 1 (in vivo) compared IOPvet estimates in normal and glaucomatous dogs to Reichert Tono-Vera&#xae; Vet rebound tonometry. The three IOPvet estimates were green (normal; <20&#x2009;mmHg, according to the manufacturer), yellow (elevated; 20-30&#x2009;mmHg), and red (high; >30&#x2009;mmHg). In Part 2 (ex vivo), the pressure inside freshly enucleated normal canine eyes was progressively increased from 5 to 80&#x2009;mmHg and compared to IOPvet estimates. Descriptive statistics compared IOPvet estimates to rebound tonometry and direct manometry, with the threshold from normal to glaucoma set at 30&#x2009;mmHg. RESULTS: In Part 1 (in vivo), normal pressures (&#x2264;30&#x2009;mmHg) were mainly identified correctly as green or yellow-110 of 111 estimates, corresponding to a specificity of 99%. Only 16 of 125 affected estimates were correctly displayed in the >30-mmHg range; the remaining 109 showed &#x2264;30&#x2009;mmHg, corresponding to a sensitivity of 13%. In Part 2 (ex vivo), all normal pressures were correctly estimated with green, but 64 of 88 manometric IOPs >30&#x2009;mmHg were falsely estimated as 20-30&#x2009;mmHg. CONCLUSIONS: The IOPvet is inaccurate in estimating canine IOP with a low sensitivity at identifying dogs with IOP&#x2009;>&#x2009;30&#x2009;mmHg. Canine-specific instrument revision is required to correctly identify elevated (yellow&#x2009;=&#x2009;20-30&#x2009;mmHg) and high (red >30&#x2009;mmHg) IOPs.