Studies on the pseudo-exfoliation material: a review.

Pseudo-exfoliation (PE) material may be found on several surfaces of the anterior segment of the eye. The material contains typical cross-banded PE fibrils distributed at random. These fibrils have been studied with transmission and scanning electron microscopy. Negative staining of dispersed PE fibrils indicated that the fibrils have a core consisting of a small number of filamentous subunits. The core is surrounded by a fuzzy material which protrudes from the fibrils at regular intervals. This is the basis of the cross-bands of the fibrils. Staining with ruthenium red and alcian blue indicates that glycosaminoglycans are present, mainly on the surface of the PE fibrils. Tracer particles have been applied in vitro on lenses with PE. The distribution of the tracers in the PE material indicates that the fibrils are embedded in an interfibrillar matrix consisting of filamentous units. It is concluded that the PE material is made up of filamentous proteo-glycosaminoglycans. The fibrils represent relatively dense aggregates of such filaments, while the interfibrillar matrix is a gel of the same filamentous units in a loose, random arrangement.