Histologic and Histochemical Changes in Rabbit Cornea Produced by an Orthokeratology Lens

Abstract

To report the histologic and histochemical properties of rabbit cornea after insertion of an orthokeratology lens. An orthokeratology lens was placed on the left corneas of rabbits for 8 hours daily, and their eyes were enucleated after 7, 14, 21, and 28 days and examined histologically and histochemically. The right eyes were used as controls. After 7-14 days, hematoxylin and eosin staining of the cornea revealed that the epithelial layer was slightly thinner in the central area and thicker in the intermediate area, but its thickness gradually became normal toward the limbus. Periodic acid-Schiff staining showed no abnormal distribution of glycogen granules or glycogen producing cells. 5-bromo-2-deoxyuridine staining revealed more mitoses in the central area than in the intermediate area. Histochemical staining showed lactic dehydrogenase activity in the central area of the lens, whereas alkaline phosphatase activity and beta-glucuronidase activity were slightly increased in the intermediate area. There were no other clearly abnormal findings. The thickness of the corneal epithelium showed topographical variation consistent with the effect of orthokeratology. The result of histochemical studies suggested that there were no marked alterations in epithelial function.