[Contractile elements in proliferative retinal diseases].

Contraction of epiretinal membranes remains the leading cause of failure in retinal surgery. The mechanism of contraction of cellular units is as yet unknown. We have used immunohistochemical methods to demonstrate the intracellular localization of the proteins actin, myosin, tropomyosin and vinculin, which are thought to be responsible for cellular contraction, in 26 surgically obtained epiretinal traction membranes from patients with traumatic (n = 12) and idiopathic (n = 7) proliferative vitreoretinopathy, and proliferative diabetic retinopathy (n = 7). The use of cell marker proteins for glial cells (GFAP) and retinal pigment epithelium (cytokeratin) demonstrates that the prevalence of contractile components is independent of cellular construction. We suggest that an intracellular mechanism is responsible for the contraction of epiretinal membranes in proliferative vitreoretinal disorders.