Idiopathic progressive unilateral vitreous fibrosis and secondary traction retinal detachment

Two eyes with idiopathic progressive avascular fibrocellular proliferation involving the posterior vitreous surface and causing visual loss due to traction on the optic nervehead, peripapillary retina, and macula were studied. This occurred in one eye of each of two elderly patients. There were no other apparent abnormalities. Vitreous surgery was used to remove the posterior vitreous surface and most of the abnormal tissue. This reduced the traction on the retina, although partial visual loss persisted because of chronic macular edema in each case. Ultrastructural examination of the excised tissue confirmed the fibrocellular nature of the membranes. New-formed collagen was identified in one case, indicating collagen synthesis by the cellular elements. The cells were identified as fibrocytes and myofibrocytes. The latter cells contained cytoplasmic microfilaments thought to be contractile protein, and contraction of the cells was thought to account for the vitreoretinal traction observed clinically. The origin of these cells could not be established by ultrastructural criteria, although clinical features suggest that cells (possibly fibrous astrocytes) from the optic nervehead were responsible for the cellular proliferation.