Variational analysis of the mouse and rat eye optical parameters

Rodent models are increasingly used to study refractive eye development and development of refractive errors; however, there is still some uncertainty regarding the accuracy of the optical models of the rat and mouse eye primarily due to high variability in reported ocular parameters. In this work, we have systematically evaluated the contribution of various ocular parameters, such as radii of curvature of ocular surfaces, thicknesses of ocular components, and refractive indices of ocular refractive media, using variational analysis and a computational model of the rodent eye. Variational analysis revealed that not all variation in ocular parameters has critical impact on the refractive status of the eye. Variation in the depth of the vitreous chamber, thickness of the lens, radius of the anterior surface of the cornea, radius of the anterior surface of the lens, as well as refractive indices for the lens and vitreous, appears to have the largest impact on the refractive error. The radii of the posterior surfaces of the cornea and lens have much smaller contributions to the refractive state. These data provide the framework for further refinement of the optical models of the rat and mouse eye and suggest that extra efforts should be directed towards increasing the linear resolution of the rodent eye biometry and obtaining more accurate data for the refractive indices of the lens and vitreous.