Proliferative vitreoretinopathy

Characterized by growth and migration of preretinal or subretinal membranes.

Contraction of these membranes causes foreshortening of the retina, leading to stretch holes or traction, which redetaches the retina (after repair of RD).
As the proliferation matures, the once compliant retinal tissue becomes rigid and immobile, making repair of RD more difficult.

Patients often have extensive levels of visual loss. .

RISK FACTORS

In general, processes that increase vascular permeability are more likely to increase the probability of PVR formation.

Specific risk factors that have been identified include: uveitis; large, giant, or multiple tears; vitreous hemorrhage, preoperative or postoperative choroidal detachments; aphakia; multiple previous surgeries; and large detachments involving greater than 2 quadrants of the eye.

CLASSIFICATION

According to Silicone Study Group:
Grade A is limited to the presence of vitreous cells or haze.

Grade B is defined by the presence of rolled or irregular edges of a tear or inner retinal surface wrinkling, denoting subclinical contraction.

Grade C is recognized by the presence of preretinal or subretinal membranes. Grade C is further delineated as being anterior to the equator (grade Ca) or posterior to the equator (grade Cp) and by the number of clock hours involved (1 to 12).

MANAGEMENT OF PVR

The current management of PVR primarily involves surgical remedy. Currently retinal detachments may be repaired using any of several techniques, including laser retinopexy, pneumatic retinopexy, encircling or segmental scleral buckling, or pars plana vitrectomy (PPV).


source:
http://www.retinalphysician.com/article.aspx?article=101327