Rhegmatogenous retinal detachment in Labrador retrievers. II. Proliferative vitreoretinopathy.

We observed proliferative vitreoretinopathy in Labrador retrievers with spontaneous rhegmatogenous retinal detachment. Cellular membranes and their associated connective tissue matrix were prominent on the surfaces of the detached formed vitreous and on the retina. Membrane contraction folded the underlying vitreous and retina and exerted traction on the structures to which they attached. Proliferation occurred in the retinal pigment epithelium under the detached retina and in the nonpigmented ciliary epithelium when it became detached. Retinal pigment epithelial cells, nonpigmented ciliary epithelial cells, macrophages, and glial cells appeared to contribute to the membranes. Our findings suggested a sequence that began with vitreous abnormalities and ended with fibrocellular membranes on the surfaces of the vitreous and the totally detached retina. Because a similar sequence can develop in humans, these dogs may be useful in future studies of proliferative vitreoretinopathy.