Clinical, electron microscopic, and immunohistochemical study of the corneal endothelium and Descemet's membrane in the iridocorneal endothelial syndrome.

Two women with the iridocorneal endothelial syndrome had unilateral corneal edema, iris stromal atrophy, and glaucoma. Each underwent penetrating keratoplasty. Transmission electron microscopy of the corneal buttons disclosed a thin, normally structured Descemet's membrane bounded posteriorly by a posterior collagenous layer that contained banded and fibrillar tissue, indicating that the disorder was acquired after childhood. Scanning electron microscopy showed some degenerated corneal endothelial cells with filopodial cytoplasmic projections, suggesting endothelial migration. Transmission electron microscopy of the endothelium showed no signs of epithelial-like alteration, such as stratification, desmosomal junctions, or increased cytoplasmic fibrils. Immunohistochemical staining of fresh-frozen sections with monoclonal antibodies to keratin showed normal staining of the epithelium and no staining of the endothelium. Occasional lymphocytes were seen within the endothelium in one case but were also observed in one case of an inherited corneal disease, posterior polymorphous dystrophy, suggesting that they might be normal "passenger" cells migrating in the endothelial monolayer.