The infant cornea contains many densely packed cells with large nuclei and little cytoplasm. As the cornea grows during childhood, cell density decreases by almost 50% and the cells become correspondingly larger. The adult cornea maintains a relatively uniform density of hexagonal cells which retain a generally uniform size and appearance. In the aged cornea, however, a pleomorphism develops. The aged endothelial surface is covered by a mixture of enormous as well as very small cells.