PVR is a complication of rhegmatogenous retinal detachment which can occur only in predisposed eyes. Preoperative PVR and postoperative PVR can develop solely in retinal detachments associated with retinal breaks related to vitreous traction (horse-shoe tears, operculated tears, crescent tears and paravascular tears of the postequatorial region). PVR never develops in retinal detachments due to retinogenic retinal breaks (atrophic holes in lattice, and oral dialysis). There are 3 independent risk factors for postoperative PVR whose role has been demonstrated: preoperative PVR, horse-shoe tears extending on 90 degrees or more of the eye circumference, and horse-shoe tears with a curled and fixed posterior edge. The role of preoperative choroidal detachment as an independent risk factor, although likely, remains to be demonstrated. Cryotreatment is a risk factor for postoperative PVR solely in predisposed eyes. An alternative method to cryo should be used in high risk eyes.