Epivascular glia and paravascular holes in normal human retina.

We examined the retinal surface of 28 autopsy eyes by scanning electron microscopy (SEM). Glialike cells or their processes, arranged in rows, were observed along retinal vessels in 22 eyes. Additionally, there were clusters of glialike cells over retinal vessels in 8 eyes. These proliferations ranged from focal to extensive ones, the latter resulting in distinct preretinal membranes. Focal defects of the superficial retina along the vessel were noted in 6 of 28 eyes. Transmission electron microscopic study in 2 surgically enucleated eyes with normal retinae revealed epivascular retinal degeneration and thinning of Müller cells. Glial processes appeared to be covering the defect of the internal limiting membrane and some projections of these cells continued inwards. These findings were consistent with the SEM findings of epivascular glialike structure. Our conclusions are that epivascular glialike structures and paravascular surface defects appear as a common finding in normal senile eyes, and that occasionally membranous formations arise from the epivascular area.