Epiretinal membrane formation after vitrectomy.

Our experimental model of epiretinal membrane formation in the rabbit eye after lensectomy and vitrectomy provides a way of studying pharmacologic and surgical approaches to inhibiting epiretinal cellular proliferation and contraction in the eye that has undergone vitrectomy. We injected 400,000 tissue-cultured retinal pigment epithelial cells onto the retinal surface of rabbit eyes that had undergone lensectomy, vitrectomy, and fluid-gas exchange. By one week, a funnel-shaped detachment of the medullary rays had occurred in 100% of the injected eyes. Histologically, the cells formed an epiretinal membrane by six hours after injection and caused major wrinkling of the inner retina after 24 to 48 hours. The percentage of tritiated-thymidine-labeled epiretinal cells increased dramatically 24 hours after injection and then declined. Cellular membranes bridging the optic nerve, followed by growth and contraction of the epiretinal cells on the detached internal limiting membrane, were responsible for the closed funnel appearance of the medullary rays.