Scleral Remodeling in Early Recovery from Induced Experimental Myopia

Purpose: To explore the contribution and impact of fibrous scleral remodeling in the early recovery from lens induced myopia of chicks.

Method: Refractive error, axial length and histopathological studies were performed on chicks subject to myopic influence with -10 D goggles unilaterally on the day of hatching for a period of 14 days, after which the eyes were enucleated and immediately fixed for histopathological assessment. Three groups, myopia (measurements taken directly after 14 days), early recovery from induced myopia (chicks allowed a three-hour recovery period by removing goggles before analysis) and control (no goggles) were evaluated. The histological slides were assessed with bright field microscopy using Leica image analysis software.

Results: Early recovery from induced myopia resulted in a significant increase in the thickness of fibrous sclera to levels twice as high as the ones observed in the control or myopia groups. Histochemical staining revealed three times increase in fibroblast cell count of the early recovery from induced myopia group along with a statistically significant increase in levels of elastin contents relative to the control. However, fibroblast morphometry revealed no difference in maximum cell diameter, perimeter, and area between all experimental groups.

Conclusion: Recovery from induced experimental myopia results in fibrous scleral remodeling. Significant increase in the scleral thickness is related to heightened cell proliferation and elastic fiber contents. These results indicate that the fibrous sclera is not a passive component in the emmetropization process, but rather plays a significant and active role in the adaptation changes of the eye during early recovery from induced myopia.