Corneal endothelial response to induced myopia in the chicken

Purpose: To investigate the role of corneal endothelial surface enlargement in the chicken myopia model in inducing corneal endothelial changes. Methods: Lid suture was performed on one eye of 1-day-old cockerels. Five c hickens were killed at 1 week, and four chickens killed at each of 3 weeks, 6 weeks, and 10 weeks postnatal. The endothelial morphology was obtained b y flat mounting the endothelial surface and the subsequent digitisation. Co mparisons were undertaken between the control unsutured eye and the lid-sut ured eye endothelium, and between the central endothelial areas compared to the peripheral endothelial areas in both the myopic and the normal corneas . Calculation of the contribution to the endothelial change by hypertrophy and mitosis were calculated using Bahn's formula. Results: Total endothelial surface area increased significantly over time i n the myopic model compared to control eyes but the mean cell area of endot helial cells remained the same for both the enlarged myopic endothelial sur face area and in the normal controls. Sampling from the central and the per ipheral corneal endothelial surface also disclosed no difference. The mean cell area did increase steadily with age but was the same for both normal a nd myopic corneas. Conclusions: It would appear that there are equal contributions from hypert rophy and mitosis in the myopic group and the normal corneal group with a s lightly increasing trend towards mitotic activity in the myopic corneal end othelial layer.