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

Abstract

Lens tissue from a Morgagni cataract was examined by SEM and TEM. For SEM, after prefixation with glutaraldehyde and postfixation with the tannic acid/arginine/OsO4 non-coating (TAO) technique, and for TEM, after prefixation with glutaraldehyde, postfixation with OsO4/K4Fe(CN)6 and poststaining with uranyl acetate/lead citrate. The TAO technique seems to be a particularly suitable postfixation method for the SEM investigation of cataract tissue because of the presence of the protein structures present. The cortical region showed areas of radially, instead of concentrically, arranged lens fibres, degenerated lens fibres with holes (vacuoles), broken ball and socket connections between the lens fibres, and oval or spherical structures varying in size from 0.5-20 microns, the largest resembling a golfball, arising from the cytoplasm of degenerating lens fibres. The smallest, 0.2-0.5 microns, appear to have been expelled from the furrowed lens epithelium.

The relationship between nuclear colour and opalescence on the LOCSIII scale and physical characteristics of cataract nuclei

“…[24][25][26][27] New techniques such as photon spectroscopy for in vivo analysis of lenses remain to be further investigated. 28 Other workers have studied in vitro features such as size, 29 chemical, 30,31 dielectric properties 32 or histological appearance 33 of lenses and linked them with preoperative features such as nuclear colour, but have not examined nuclear hardness. Assia et al 8 examined the link between histological appearance and nuclear hardness, but found no relationship when simple staining techniques were used.…”

Lensfibre degeneration at cataract lenses

“…Slices then were fixed again in GA (24h; 40C), whereafter a part of the material was prepared for LM and TEM and another part for SEM according the procedure described before [14][15][16]. The lenses were then fixed in cacodylate buffered GA (2%; 2 h) and carefully sliced (2 x 2 x 2 mm) for LM, SEMen TEM, whereafter under the stereomicroscope the cortical and nuclear areas were selected.…”