[Vitreoretinal proliferation. I. Clinicopathological aspects].

Proliferative vitreoretinopathy (PVR) remains the major complication occurring after a rhegmatogenous retinal detachment, and often results in massive periretinal retraction which makes impossible any attempt in reattaching neuroepithelial layers. The most recently proposed classifications of PVR as well as clinical observations improved the understanding of PVR and suggested that some events could be of striking importance in its development, such as the size of retinal breaks, eventual haemorrhages or overdosed cryoapplications. Most interesting findings, however, resulted from the more and more powerful analysis of vitreoretinal membranes. Electron microscopy, immunohistochemistry and molecular biology techniques permitted identification of a wide variety of cellular and biological components. The majority of cells involved in PVR are from retinal or ciliary pigment epithelial, glial or inflammatory origins. Extracellular matrix are constituted with collagen, fibronectin, heparan sulfates or laminin, but they also contain growth factors, immunoglobulins and activated complement. Moreover, proliferating cells express membrane receptors to growth factors and to immunocompetent cells, which makes PVR an extraordinarily complicated biological syndrome, involving a wide range of mediators and cellular systems.