A combined scanning and transmission electronmicroscopic investigation of human (secondary) cataract material

Abstract

Cataract lenses from patients of advanced age were processed for SEM by standard pre-fixation followed by treatment by the Tannin-Arginine-Osmium-tetroxide (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 microns, 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 microns, 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.

Study of the substructure of the Morgagni and Brunescens cataract with the TAO non-coating technique

“…Some of the oval structures, measuring a few p.m, protrude from the lens membrane into the spaces between the lens fibres; other spherical structures appear to be extruded from the cytoplasm of the lens fibre [4].…”

“…In m~iny cases these problems can be solved by means of a non-coating technique [3,4], in which the ligand plays an important part, as can be seen in Table 1.…”

(An)aerobic bacteria found in secondary-cataract material

“…In an earlier study [4] it was seen that similar golfball structures were present in cataract lenses and that they were degradation products of cataractous lens fibres. These particles seem to have been left behind after the lens extraction, without at first causing problems for the patient.…”

“…Secondary-cataract formation has been described by various authors in otherwise quiet eyes [1][2][3][4]. In these eyes many different products were found in the after-cataract material, e.g., remnants of lens fibres, spherical structures, sometimes with the appearance of a golfball, erythrocytes and a mucous substance.…”

“…The purpose of our study is to describe the morphology of secondarycataract material from the quiet eyes of 24 patients following ECCE, with the help of scanning (SEM) and transmission (TEM) electron microscopy, and to compare the results with earlier findings on secondary-cataract material obtained with SEM [1][2][3][4].…”