Pre-descemetic corneal dystrophy.

Maeder and Datiis (1947) described a 40-year-old woman with small white curved filaments occupying a disc in the deepest layers of the corneal stroma. The peripheral 2 mm. of cornea remained unaffected. The corneae of this patient showed keratoconus, clinically manifest in the left eye with a forme fruste in the right. D'Ermo (1950) annotated a similar case in a 19-year-old girl who was also affected by keratoconus, and in whom the middle layers of the stroma were affected in the central area. Franceschetti, Chodos, Dieterle, and Forni (1957) described a case in which punctate and filiform opacities were found in the deepest corneal layers, again leaving the corneal periphery unaffected. The corneal nerves were prominent, but keratoconus was not present. The conditions were designated deep filiform corneal dystrophy. A similar condition, deep punctate comeal dystrophy, was first described by Franceschetti and Maeder (1954) in a 20-year-old patient. Bluish-white translucent points, some of which were prolonged into filaments, were scattered in the pre-descemetic layers. They were most densely distributed half-way between the centre and the periphery of the cornea. Under high magnification, they appeared like a knot of fine fibrils. No other corneal layers showed pathological change. The patient suffered from ichthyosis of moderate severity. The same condition was reported in a 50-year-old man with chronic simple glaucoma, and primary band-shaped degeneration of the cornea, who was also affected with congenital ichthyosis. Some of the opacities in this instance were comma-shaped and some were short rods, some straight and some angled; they occupied a central disc in the deepest stromal layers. Kraupa (1924) described deep parenchymatous corneal changes in five patients with congenital ichthyosis. The opacities were grey points and flecks appearing like snowflakes under high magnification and were less marked at the periphery of the cornea. Franceschetti and Schldppi (1957) reported, in a 56-year-old man with congenital ichthyosis and band-shaped corneal degeneration, bilateral pre-descemetic dystrophy where the opacities took the form of short irregular lines.