Membranous nature of premacular vitreous cortex in the human eye.

To characterize the morphologic nature of the premacular vitreous, we examined the posterior vitreous of 24 normal autopsy eyes without posterior vitreous detachment (PVD) by biomicroscopy and scanning electron microscopy (SEM). For biomicroscopic observation, the vitreous was stained with fluorescein and immersed in water. The posterior portion of the eyeball was then desiccated and examined by SEM. The vitreous cortex was extremely thin in the premacular area, and premacular liquefied lacuna was invariably seen in front of the thin vitreous cortex by biomicroscopic observations. In SEM the premacular vitreous cortex appeared to be a cellophane-like membrane overlying the retina at x40 approximately 100 magnification. A meshwork structure could be seen in the cellophane-like membrane at the magnification of approximately x1000. The diameter of fibers in the meshwork was compatible with that of vitreous collagen. We confirmed that the premacular vitreous cortex was of a membranous nature distinct from the vitreous gel in eyes without PVD.