• Posterior polymorphous dystrophy (PPMD) and Chandler's syndrome are separate ocular diseases with certain clinical features in common. Both may cause endothelial dystrophy, corneal edema, iridocorneal adhesions, and glaucoma. Differences between the two disorders include the morphology of the endothelial dystrophy, hereditary transmission, laterality, and rate of progression. Histopathologic examination of trabeculectomy and iridectomy specimens from two patients with PPMD and one patient with Chandler's syndrome disclosed a common basic pathologic process—endothelialization of the anterior chamber angle. Ectopic corneal endothelium and abnormal Descemet's membrane extended across the trabecular meshwork and onto the anterior surface of the iris. The appearance of the endothelial cells, however, was strikingly different in the two conditions. The endothelial cells in PPMD had ultrastructural characteristics of epithelial cells. Those in Chandler's syndrome were degenerated but retained ultrastructural features of endothelial cells.