Ocular ochronosis from alkaptonuria.

Alkaptonuria is an extremely rare, autosomal recessive disorder in which the metabolic enzyme homogentisic acid oxidase is deficient. A common sequelae is the subsequent accumulation of homogentisic acid in collagenous tissues, such as the sclera, nose and ear lobes. The blue-black pigmentation found in patients with alkaptonuria is called ochronosis. Another ocular sign includes amber-colored oil globulation within Bowmans membrane of the cornea.