Confocal microscopy of human lens membranes in aged normal and nuclear cataracts.

PURPOSE To visualize the structure and determine the continuity of lipid membranes in lens fiber cells (LFCs) from human aged normal and cataractous lenses. METHODS Thick sections from human nuclear cataracts and aged normal lenses were stained with the lipophilic probe DiI, and then analyzed by confocal microscopy. Staining patterns of membranes were observed in individual optical sections or three-dimensional projections of z-series taken in longitudinal section and cross-section of LFCs from different regions within the lens nucleus. RESULTS DiI bound to and delineated the plasma membrane of LFCs from all regions of the lens nucleus. Three-dimensional projections of z-series from aged normal and cataractous lenses suggested that some of the stained lipid membranes were not continuous with LFC plasma membrane of cataractous lenses. CONCLUSIONS The results obtained using these methods demonstrated that lipid membranes, discontinuous with the plasma membrane of LFCs, were indicative of a novel process occurring predominately in cataractous human lenses.