Keratoconus posticus circumscriptus with indentation of the lens.

UNEVEN curvature of the posterior corneal surface is a rare abnormality first described by Butler (1930). On oblique illumination the cornea presents a localized opacity not very prominent, and usually situated axially. Only about twenty cases have so far been reported. Ingram (1936), Goldsmith (1943), Leopold (1943), Wise (1944), and Greene (1945) did not mention any associated abnormality of the curvature of the lens. Mann (1957) reported two cases of umbilication of the posterior lenticular surface. Livant (1956) reported a case of bilateral indentation of the anterior surfaces of both cornea and lens. The following case appears to be unique.