Abstract
Purpose :
Both pigs and rabbits are commonly used as translational models. Various tonometers have been validated in both of these species, however, the Tono-Vera® Vet has not yet been evaluated in rabbit and pig eyes. The goal of this study was to compare the species-specific settings of this tonometer to determine which is the most appropriate for use in these species.
Methods :
Six freshly enucleated rabbit eyes and five freshly enucleated pig eyes were cannulated and connected to a fluid reservoir and physiologic monitor. Triplicate measurements were obtained at various intraocular pressures (IOP) ranging from 5-80mmHg on each of the four species specific settings: dog, cat, horse, and rabbit. Linear regression and Bland-Altman analysis were utilized to determine linear regression formulas, bias, and 95% limits of agreement for each setting.
Results :
In both rabbit and pig eyes, all settings demonstrated strong positive linear trends. In pig eyes, all settings demonstrated proportional bias except for the dog setting which suggests it is the most accurate in this species. The average bias of the dog setting in pig eyes was -2.00 mmHg. This underestimation was consistent at all manometric pressures. The dog setting had the smallest 95% limits of agreement compared to the other settings (-7.52, 3.53 mmHg) indicating it is the most precise setting in pig eyes. In rabbit eyes, all settings demonstrated proportional bias, however the average bias of the rabbit setting was the smallest (-2.73 mmHg), suggesting that the rabbit setting is the most accurate. The 95% limits of agreement were the smallest for the rabbit setting (-12.21, 6.76 mmHg) compared to the other settings in rabbit eyes indicating it is the most precise setting as well. The rabbit setting approached zero bias at IOPs less than 30mmHg, but tended to underestimate IOP to a greater degree as true manometric pressure increased.
Conclusions :
This data suggests that when using the Tono-Vera® Vet rebound tonometer, the dog setting is the most appropriate setting for use in pig eyes, and the rabbit setting is the most appropriate for use in rabbit eyes.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.