Unit Membrane Redundancy in Spherical Structures Within the Ocular Lens

Abstract

‘Spherical structures’, found in the nuclear region of some rabbit lenses have been observed with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Their surface ultrastructure, as seen with SEM, is similar to that of fiber cells normally seen in this region of the lens. However, TEM reveals that multiple unit membranes (2–10) make up their surface. Evidence for the possible mode of origin of this membrane redundancy is presented and discussed. Comparisons and contrasts are made with globular structures seen in human cataractous lenses. Differences between these ‘spherical structures’: seen in the rabbit, and ‘globular structures’ seen in human cataractous lenses are discussed.