Structure of the vitread face of the monkey optic disc (Macaca mulatta). SEM on frozen resin-cracked optic nerveheads supplemented by TEM and immunohistochemistry.

The authors applied frozen resin cracking after hexamethyldisilazane (HMDS) desiccation on the monkey optic disc region. The cracked face through the central part of the optic disc showed that the inner limiting membrane of the retina continued into the limiting membrane of Elschnig, and this, in turn, continued into the central meniscus of Kuhnt. At the disc margin the membrane was about 70 nm in thickness, due to a large fibrillar component. Elschnig's membrane was about 50 nm in thickness and was composed of both fibrils and flocculent material. The membrane covering the central meniscus of Kuhnt was about 20 nm in thickness. The number of fibrils here was very low, and the membrane consisted of flocculent material. The positive immunohistochemical stainings for GFA and vimentin of Elschnig's membrane and Kuhnt's meniscus were noteworthy. The positive staining disappeared when the membrane continued into the inner limiting membrane of the retina, supporting the different structural composition.