Effects of Form Deprivation on Eye Size and Refraction in C57BL/6J Mice: :

Abstract

Abstract: : Purpose: Because the mouse has a well–defined genome, it provides a powerful model in which to study the factors influencing refractive development. However, it must be established that mice respond to form deprivation as observed in other species. Methods: At 28 days of age eight mice were fitted with a monocular diffuser goggle over their right eyes while the left eyes were unmanipulated. Four mice were used as controls. The mice were housed under 30–100 lux illumination and goggle compliance was monitored several times a day. Mice were refracted after cycloplegia at 2, 6 and 8 weeks post–goggling with an automated eccentric autorefractor, which also measured pupil size. Five measurements were made for each eye at each time point. Mice were sacrificed at 2 (n = 5) and 8 (n = 3) weeks post–goggling and their eyes enucleated and photographed under a dissecting microscope to determine axial length. Results: After two weeks of form deprivation, no differences were detected in refractive value or axial length between goggled and unmanipulated eyes (+9.72 ±2.36 and +10.5 ±0.67 D; 3.15 ±0.03 and 3.16 ±0.05mm). After 6 weeks of form deprivation, goggled eyes showed a myopic shift relative to the opposite eye (6 wks: +10.36 ±0.34 and +12.19 ±0.26 D; p<0.03). At 8 weeks, the myopic shift between the goggled and unmanipulated eyes was even greater (+10.09 ±0.44 and +12.53 ±0.15D; p<0.03). However, no differences in axial length could be measured (3.16 ±0.005 and 3.2 ±0.0008mm). No significant differences in pupil size were detected between eyes at any timepoint. Goggle compliance varied from 97.6 to 100%. Conclusions: While not producing large myopic shifts seen in other species, C57BL/6J mice will respond to form deprivation with a modest myopic shift. Future studies will determine whether other environmental and genetic factors can influence refractive development in mice.

Keywords: myopia • refractive error development • refraction