INVESTIGATIVE OPHTHALMOLOGY The histological and ultrastructural pathology of congenital hereditary corneal dystrophy: A case report

This case report describes the pathological changes found in the markedly clouded and thickened corneal button from a child with bilateral congenital hereditary corneal dystrophy. When surveyed by light and electron microscopy, three types of abnormalities were evident: (1) superficial changes including small subepithelial bullae, interruptions of the thickened epithelial basement membrane, anchoring fibrils associated with the central corneal basement membrane, and thickness variations in Bowman's layer; (2) stromal alterations, including disorganization of the stromal lamellae and enlargement of the collagen fibrils to almost twice normal diameter; and (3) a uniformly thinned Descemet's membrane with ultrastructural anomalies suggestive of a functionally defective endothelium. Although the superficial changes are for the most part nonspecific, the increased collagen fibril diameter may constitute a congenital stromal defect of diagnostic significance which is shown here for the first time. The alterations of Descemet's membrane and the indications of endothelial dysfunction are interpreted to implicate a congenital form of endothelial dystrophy as a possible factor in the pathogenesis of congenital hereditary corneal dystrophy.