Impact of Extended Lens-Induced Myopia on Retinal Structure and Function in Mice.

Purpose: To investigate time-dependent structural and functional retinal alterations in a mouse model of prolonged lens-induced myopia.

Methods: Myopia was induced in male C57BL/6J mice by fitting -30 D lenses on both eyes starting at postnatal week 3. Mice were assigned to either a long-term induction group (3-9 weeks of age) or a short-term induction group (3-6 weeks of age). Separate groups fitted with 0 D lenses served as controls. Ocular parameters, including refraction, axial length, choroidal thickness, and retinal thickness were measured at weeks 3, 6, and 9 using an infrared photorefractor and spectral-domain optical coherence tomography. Retinal function was assessed by dark-adapted electroretinography at week 9 for the long-term group and at week 6 for the short-term group. Statistical analyses included two-way repeated-measures ANOVA followed by Bonferroni's post hoc test for comparisons across groups and time points, and two-tailed unpaired t-test or one-way ANOVA with Fisher's LSD post hoc test for group comparisons at individual time points.

Results: After 6 weeks of myopia induction, the long-term myopia group exhibited significant reduction in refraction, axial length elongation, and choroidal thickness thinning. Inner retinal thickness was markedly reduced, and electroretinography revealed attenuated amplitudes and delayed implicit times of the oscillatory potentials.

Conclusion: Prolonged lens-induced myopia in mice induces time-dependent structural and functional retinal alterations, particularly in the inner layers. This model underscores the significance of early retinal monitoring under long-term myopic conditions and serves as a platform for investigating retinal vulnerability and developing preservation strategies over time.