THE PATHOGENY OF PROLIFERATIVE VITREORETINOPATHY

Proliferative vitreoretinopathy (PVR) is the most important complication of rhegmatogenous retinal detachment (RRD) and the main cause of RRD surgery failure. This is a review of recent literature data, which concerns PVR pathogeny and risk factors. The occurrence of pre- and subretinal membranes is a consequence of retinal pigment epithelial cells activation and migration, with concomitant participation of inflammatory cells. The newly synthesized extracellular matrix interacts with cells promoting membrane contraction. Photoreceptor apoptosis limits functional recovery--but there is ongoing research for neuroprotective mechanisms. A lot of evidence has been accumulated about the role of growth factors (PDGF, VEGF, HGF, EGF, TGF α and β, G-CSF, FGF, IGF-1,CTGF), cytokines (interleukins IL-1, -6, -8, -10 and interferon γ), matrix metalloproteinases and chemokines, by measuring their concentrations in the vitreous or the subretinal fluid of PVR patients. A list of risk factors (common or more controversial) may help the surgeon make the best approach for the management of individual cases. Adjuvant therapies tested for PVR prevention (steroids, heparin, 5 fluorouracil, daunomycin, colchicine and 13-cis retinoic acid) did not enter current practice, but there are numerous research directions currently being developed.