Electron microscopic observations on the cilio-zonular border area of the human eye with particular reference to the aging changes.

Abstract

The basement membrane at the inner surface of the nonpigmented ciliary epithelium is the direct continuation of the basement membrane at the inner surface of the neural retina. It shows a remarkable transformation during life. In the early childhood it is one-layered, whereas in the adult eye it forms a multi-layered network. This may be caused by aging processes or by biomechanical forces. Within the mashes of the aged basement membrane network, granular and lamellar deposits, probably lipids, are interposed. The “nonpigmented” ciliary epithelium cells are not absolutely free of pigment. Electronmicroscopically we found melanin granules and melanosomes also in the “nonpigmented” cells of the pars plana corporis ciliaris of a 9 month old child. With increasing age, the nonpigmented ciliary epithelium cells contain an increasing number of lipid droplets, lipofuscins and vacuoles.