Comparison of the use of new handheld tonometers and established applanation tonometers in dogs.
OBJECTIVE
To examine the practical aspects, accuracy, and reproducibility of 2 new automatic handheld tonometers in dogs and compare them with results for 2 established applanation tonometers.


METHODS
15 freshly enucleated canine eyes for manometric evaluation and 20 conscious research dogs, 20 client-owned dogs, and 12 dogs with acute glaucoma for clinical tonometry.


METHODS
Calibration curves were determined for all 4 tonometers on 15 enucleated canine eyes. Intraocular pressure (IOP) was measured with each tonometer consecutively in conscious dogs, with the MacKay-Marg applanation tonometer as the reference device. Measurements were repeated in 20 sedated dogs. An induction-impact tonometer was evaluated clinically on dogs with acute glaucoma. Additionally, measurements obtained by an experienced and an inexperienced examiner and with or without use of topical anesthesia were compared.


RESULTS
The portable pneumatonometer was cumbersome and time-consuming. Compared with results for the reference applanation tonometer, and confirmed by manometry, the portable pneumatonometer increasingly underestimated actual IOP values with increasing IOP. The induction-impact tonometer provided accurate and reproducible measurement values. There was a significant strong correlation between the IOP values obtained by the 2 examiners (r2, 0.82) and also with or without topical anesthesia (r2, 0.86). In dogs with glaucoma, the fitted line comparing values for the reference applanation tonometer and induction-impact tonometer closely resembled an ideal 1:1 relationship.


CONCLUSIONS
Use of the portable pneumatonometer in dogs appears to have disadvantages. The induction-impact tonometer appears to provide a promising alternative to the use of applanation tonometers in dogs.
Görig
Christiane
C
Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, University of Utrecht, Yalelaan 8, 3508 TD Utrecht, The Netherlands.
Coenen
Roel T I
RT
Stades
Frans C
FC
Djajadiningrat-Laanen
Sylvia C
SC
Boevé
Michael H
MH
D000818:Animals; D004283:Dog Diseases / Q000175:diagnosis*; D004285:Dogs; D005069:Evaluation Studies as Topic; D005901:Glaucoma / Q000175:diagnosis / Q000662:veterinary*; D007429:Intraocular Pressure / Q000502:physiology; D014065:Tonometry, Ocular / Q000295:instrumentation* / Q000379:methods / Q000662:veterinary*