Advanced pigmentary retinal degeneration: an ultrastructural study.

A case of advanced pigmentary retinal degeneration is described. Posterior subcapsular cataract and a remnant of the anterior hyaloid system on the posterior lens surface were found. Extensive dispersion of pigment and organization of the vitreous base were present. Gliosis was seen in the retina, and no photoreceptors were evident. The retinal blood vessel walls were extensively hyalinized, with cell debris and deposition of basement-membrane-like material, which may have originated from perivascular pigment-laden cells of pigment epithelial origin. The pigment epithelium showed extensive proliferation in clumps. Pigmented retinal pigment epithelium (RPE) cells without lipofuscin, migrating nonpigmented RPE cells, and macrophages with large lysosomal bodies could be identified in each clump. An abundance of extracellular basement-membrane-like material or mucopolysaccharide was seen in the retina and adjacent to the RPE. This material probably originated from the abnormal RPE. Abnormalities of the large and small choroidal vessels are present.