Precapsular film on the aging human lens: precursor of pseudoexfoliation?

Abstract

In many older patients we observed a layer of subtle opacification on the anterior lens capsule, appearing as a ground glass film biomicroscopically. This precapsular film (PCF) could be uniform but often had radial grey lines in the mid zone, holes in the paracentral region, and was occasionally rolled up in strings. Lens capsular material obtained at cataract extraction was studied in patients with and without the film. By scanning electron microscopy the PCF appeared as a friable, incomplete fibrillar layer, with rolling of the edges suggesting loose attachment. Ultrastructurally its component fibrils were from 3-6 nm in diameter, similar to the finer fibrils in pseudoexfoliation (PSX) material. Life PSX material the layer stained positively for the elastic microfibril-associated protein, fibrillin, in a lens with radial striations. These similarities suggested that the two conditions have some relationship and that the PCF may be a precursor of PSX. Finding patches of the fibrillar network in some control patients implies that the PCF is common in patients of cataract age, though seldom detected clinically.