Ultrastructure of epiretinal membrane causing retinal starfold.

A prominent posterior retinal "starfold" was seen in an eye with an extensive rhegmatogenous retinal detachment. The retina was reattached with a scleral buckling operation. The epiretinal membrane causing the starfold was later removed by vitreous surgery and was studied by electron microscopy, permitting the first such clinicopathologic correlation in a human eye. The membrane was composed of vitreous collagen, newly formed collagen, and cells. The cell types included retinal pigment epithelial (RPE) cells, fibrous astrocytes, and macrophages. The fibrous astrocytes and some of the RPE cells contained intracytoplasmic microfilaments of the type thought to be myofibrils. These may account for contraction of the membrane, causing the starfold configuration of the underlying and adjacent retina.