Stereoscopic Images of Human Cataractous Lens Fibers Obtained with Field Emission Scanning Electron Microscopy

Segments of healthy human lenses and lenses with an anterior cortex cataract, prefixed in glutaraldehyde and subsequently postfixed in a mixture of tannic acid arginine osmium tetroxide, were examined by stereo-scopic imaging at 2 kV in a field emission scanning electron microscope. The degeneration process of the lens fibers was identified by the presence of spherical bodies or vacuoles in the cytoplasm of the lens epithelial cells, porosity and granulation of the lens fiber membrane and opening (distortion) of the lens fiber interdigitation system. The spherical bodies, containing either a viscous or a low density material, escaped from the cytoplasm penetrating the porous lens cell membrane at several places; this could in particular be observed at the intercellular space between the lens fibers. The stereoscopic pairs of images gave a realistic threedimensional impression of the ongoing structural alterations during the degeneration process, especially the formation of globular vacuoles protruding from the lens epithelial cytoplasm and their subsequent escape.