A COMBINED SCANNING AND TRANSMISSION ELECTRON-MICROSCOPIC INVESTIGATION OF HUMAN (SECONDARY) CATARACT MATERIAL

Cataract lenses from patients of advanced age were processed for SEM by standard pre-fixation followed by treatment by the Tannine-Arginine-Osmiumtetroxide (TAO) method and critical point drying, and for TEM by standard pre-fixation followed by vibratomation, standard post-fixation, ultramicrotome sectioning and staining with uranyl acetate/lead citrate. Secondary cataract material was brought onto a Millipore filter, fixed by standard methods, dried in air and sputter-coated with Au. Both SEM and TEM images revealed degeneration processes in lensfibre material, such as swelling of the lensfibre, protrusion of the cytoplasm, fibrillation of the cell membrane, loss of the nucleus, spherical bodies of various sizes between 0.5-1.5-mu-m, sometimes surrounded by a (double) membrane with different contrast but without cellular evidence, and small and large vacuoles partly filled with granular material both in and at the periphery of the lensfibre-body. The secondary cataract material on the Millipore filter revealed erythrocytes and more or less spherical bodies with high contrast, measuring between 0.5-1.5-mu-m, often referred to as Elschnig's pearls, besides non-definable organic material. The SEM and TEM micrographs of the cataract lens material strongly suggest that the spherical bodies with sizes of approximately 0.5-1.5 micrometer and high contrast without cellular evidence, are similar to the more or less spherical bodies found in the secondary cataract material on the filter, referred to as Elschnig's pearls.