Pathology of posterior polymorphous degeneration of the cornea.

POSTERIOR polymorphous degeneration of the cornea is an uncommon, non-progressive, hereditary condition which is usually bilateral; in the majority of cases there is only minimal visual impairment (Duke-Elder and Leigh, 1965). The condition was first described by Koeppe (1916) as "keratitis bullosa interna", on account of the congenital pits on the posterior corneal surface. Koeppe (1920) reported eighteen additional cases which he considered to be of congenital origin because of the absence of other ocular changes. Further cases have been reported by Triebenstein (1925), Freudenthal (1932), and Theodore (1939). Franceschetti, Klein, Forni, and Babel (1951) described the condition as showing "slight concavities, vesicles, and polymorphous opacities in the posterior limiting membrane". Its hereditary nature as a dominant trait is now well recognized (Freudenthal, 1932, in a father and son; Theodore, 1939, in a grand-mother, father, and daughter; McGee and Falls, 1953, in a father and son; Soukup, 1964, in two sisters). Franceschetti and Montresor (1960) described the condition in association with band-shaped degeneration of the cornea, and Bergman (1964) reported a case in which there was heterochromia of the brows and lashes. The purpose of this paper is to describe for the first time the pathological changes of the condition.