Purpose: To investigate refraction, corneal curvature, axial components, and the correlations between the refraction and ocular growth during the emmetropization in the C57BL/6 mouse.
Methods: Ten groups of 10 mice underwent ocular measurements at 22 to 102 days after birth. Refraction was measured by photoretinoscopy and corneal radius of curvature (CRC) was measured by keratometry. Corneal thickness (CT), anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD), retinal thickness (RT), and axial length (AL) were measured by optical coherence tomography (OCT) with focal plane advancement.
Results: Refraction was -1.49 +/- 3.17 diopters (D; mean +/- SD) at day 22 and the highest myopia was at day 25 (-4.61 +/- 2.96 D). The refractive error then increased and reached a hyperopic peak (+9.43 +/- 3.33 D) on day 47. The overall change in refraction was significant from 22 to 102 days (P < 0.05). All measured ocular components changed significantly during the study period except for CT and RT (P > 0.05 for CT and RT; P < 0.05 for others). The CRC, ACD, LT, and AL increased from 22 to 47 days. The increase in ACD, LT, and AL continued after 47 days; however, the CRC increased slowly after this age. The ACD became stable around 67 days and LT and AL at 81 days.
Conclusions: In C57BL/6 mouse eyes, myopia developed early and then the refractive error increased rapidly in the hyperopic direction to reach a peak at around 47 days with the major contributing changes being in axial length and corneal curvature.