Comparative study on ocular anatomical features among rabbits, beagle dogs and cynomolgus monkeys

Abstract

Comparative research on the ocular anatomy among species has been widely carried out. Such information is crucial in laboratory animals to evaluate non-clinical data for development of ophthalmologic products; however, the information is rather dispersed, and there is no comparative data available or not easily accessible for such animal species as rabbits, beagle dogs, or cynomolgus monkeys commonly used in researches with dosing manners of ocular instillation and intravitreous injection. The purpose of this study is to provide data on comparison of the ocular anatomical features in rabbits, dogs and monkeys.
The size of the eyeball (the axial length, weight and volume), the size of lens (the thickness, weight and volume) and the size of vitreous (the weight and volume) were measured in each species. In comparison among these 3 species, the size of the eyeball was found to be the largest in dogs, followed by monkeys and rabbits. There was a positive correlation between the eyeball size and body weights. The size of the lens was the largest in dogs, followed by rabbits and monkeys, which did not correlate with the eyeball size or body weight. The size of the vitreous was the same order of the eyeball size, but the relative value to the eyeball was found to be the largest in monkeys.
In this study, the sizes of eyeball, lens and vitreous were compared in detail among rabbits, dogs and monkeys, which are frequency used for ocular research. These findings would provide significant and useful information when evaluating non-clinical studies and extrapolating animal experimental results to human.