Figure 1.

Schematic representation of the human cornea in cross-section. This avascular tissue is basically composed of three composite regions. The outermost anterior layer is the epithelium, which is followed by the stroma, which is the thickest layer of the cornea and is composed of keratocytes and collagen. The third portion is the endothelium, which is a monolayer of cells that lies adjacent to the aqueous humor. Bowman’s connective tissue layer and Descemet’s membrane are two acellular structures that connect the other portions of the cornea.