Membrane removal in proliferative vitreoretinopathy

Early investigators suggested that the cellular basis of proliferative vitreoretinopathy (PVR) is the result of proliferating retinal pigment epithelial (RPE) cells, as well as retinal glial cells. RPE cells have been identified by both light and electron microscopy on the retinal surface of longstanding detachments. Proliferating RPE cells can transform into myofibroblast-like cells, which extend pseudopods to pull and contract a strand of collagen in a ‘hand-over-hand’ manner, resulting in retraction of the vitreous body. The major clinical finding with PVR is of fixed folds, which are classified by the extent of retinal folding. The crystalline lens will prevent removal of the anterior vitreous and membranes, which is a critical aspect of surgical repair of PVR. In air- or gas-filled eyes, more effective laser treatment can be achieved by using a panfunduscopic contact lens in conjunction with a longer-wavelength laser, such as a diode or krypton red laser, and long exposure times.