Ultrastructure of epiretinal membrane removed by pars plana vitreoretinal surgery.

Electron microscopic study of an epiretinal membrane obtained from a 69-year-old black woman during pars plana vitreoretinal surgery with vitreous hemorrhage complicating a retinal vein obstruction revealed extensive proliferations of fibrous astrocytes that had secreted fibrillar and basement-membrane collagens. Hemosiderin-containing macrophages were also found. Neovascular elements were present and appeared identical to normal retinal capillaries.