Pseudo-exfoliation material. Electron microscopy after the application of lanthanum as tracer particles and ionic stain.

Lenses with pseudo-exfoliation (PE) were suspended in a solution of lanthanum, which was present partly in ionic form, partly as electron-dense tracer particles in colloidal solution, dependent on pH and on the concentration of lanthanum. By electron microscopy the tracer particles were found in a narrow zone along the surface of the PE excrescences. Only a few of the smallest particles had penetrated into their most superficial layer. In the specimens treated with ionic lanthanum, the effect was an electron-dense staining of the PE material within a 1-2 micrometer thick superficial layer. The PE fibrils as well as parts of the interfibrillar spaces were stained. These results indicate the presence of proteoglycans, and confirm the concept of an interfibrillar matrix which excludes other macromolecules and particles from penetrating into the material.