Validation of the Reichert® Tono‐Vera® Vet rebound tonometer in normal ex vivo canine eyes

Abstract

ObjectiveTo determine the accuracy of the Reichert® Tono‐Vera® Vet rebound tonometer for canine intraocular pressure (IOP) measurement.Animals StudiedFive normal canine ex vivo globes.ProceduresThe anterior chambers of five freshly enucleated normal canine eyes were cannulated and connected to a reservoir of Plasma‐Lyte A and a manometer. Starting at a manometric IOP of 5 mmHg, the pressure was progressively increased to 80 mmHg by raising the reservoir. Triplicate IOP measurements were taken with the Tono‐Vera® Vet from the central cornea using the dog setting and compared to the manometric pressure by linear regression analysis and Bland–Altman plots.ResultsThere was a strong positive linear regression trend when comparing central corneal Tono‐Vera® Vet IOPs to manometric pressures (r2 = .99) with solid agreement between the two methods. Compared to manometric IOPs, the Tono‐Vera® Vet underestimated IOPs at higher pressures ≥70 mmHg.ConclusionsMeasurement of IOPs from the central cornea with the Tono‐Vera® Vet provided accurate results over a large range in normal canine globes compared to direct manometry. The mild to moderate underestimation of IOPs at high pressures was not considered clinically relevant.