Accuracy and reproducibility of the TonoVetReg. rebound tonometer in birds of prey. (Special Issue: Zoo and exotic animals.)

摘要

Objective: To examine the accuracy and reproducibility of intraocular pressure (IOP) measurements obtained by the TonoVetReg. rebound tonometer. Animals studied: Freshly enucleated healthy eyes of 44 free-ranging birds of prey out of the species Haliaeetus albicilla, Accipiter gentilis, Accipiter nisus, Buteo buteo, Falco tinnunculus, Strix aluco, Asio otus and Tyto alba euthanized because of unrelated health problems. Procedures: IOP readings from the TonoVetReg. were compared with a manometric device, with IOP being set from 5 to 100 mmHg in steps of 5 mmHg by adjusting the height of a NaCl solution reservoir connected to the eye. Reproducibility of the TonoVetReg. readings was determined by repeated measurements. Results: TonoVetReg. and manometer values showed a strong linear correlation. In the Accipitridae, the TonoVetReg. tended to increasingly overestimate IOP with increasing pressure, while in the other families, it increasingly underestimated it. In the Sparrowhawk, the values almost represent the ideal line. Reproducibility of TonoVetReg. values decreases with increasing pressure in the clinically important range from 5 to 60 mmHg. Conclusion: IOP values measured with the TonoVetReg. demonstrated species specific deviation from the manometric measurements. These differences should be considered when interpreting IOP values. Using the regression formulae presented, corrected IOP values could be calculated in a clinical setting.