Role of the Pericorneal Papillary Structure in Renewal of Corneal Epithelium

Abstract

THE human cornea is covered by a five-layered epithelium. Cells are continually shed from its surface and replaced by division of the basal cells, which has a mean generation time estimated to be about 4 days¹. Because of the papillae in the skin, the relation between the area of the basal cell layer and the surface is about 20 : 1. Because it must be refractive, there can be no papillae on the cornea, and the relation between the basal cell layer and the surface is accordingly 1 : 1. This should correspond to higher demands on the generative capacity of the corneal basal cells compared with skin. The epidermal basal cells are in close contact with a well developed capillary network. There are no vessels in the cornea, and so it can be assumed that the supply of its epithelium is poorer. Corneal epithelium, nonetheless, has considerable healing capacity, which is achieved primarily by migration of epithelial cells.