Specific Densified Regions in the Postlaminar Human Glaucomatous Optic Nerve

PURPOSE: To describe ‘densified regions’ in human postlaminar optic nerves of donors with the clinical diagnosis of primary open angle glaucoma (POAG) and pseudoexfoliation glaucoma (PEXG). METHODS: Optic nerves of 25 eyes with POAG and of 19 eyes with PEXG were investigated. Clinical data and axon counts of Epon-embedded semi-thin sections were used to determine the stage of the disease. Ultrathin sections were performed of selected areas and studied with an electron microscope. Immunofluorescence staining of paraffin sections was performed including antibodies against glial fibrillary acidic protein (GFAP), neural cellular adhesion molecule, vimentin and laminin. RESULTS: Early changes in both types of glaucoma showed increased numbers of areas with a densified appearance. The lack of GFAP staining and of ultrastructurally light nuclei within these areas indicated loss of astroglia. CONCLUSION: For the first time, a special type of neurodegeneration in optic nerves with mild glaucomatous changes is described.