Ochronosis of the Sclera and Cornea Complicating Alkaptonuria

Medical works of the sixteenth and seventeenth centuries cite instances of urines which were black when voided or which darkened on exposure to air. In 1858 Boedeker1found in the urine of a patient with glycosuria a second reducing substance, not a sugar, to which, on account of its behavior toward alkalis, he assigned the name alkapton. Marshall2in 1887 discovered the true nature of alkapton to be glycosuric acid. Wolkow and Bauman named the reducing substance homogentisic acid because it is a homologue of gentisic acid and showed that the peculiar properties of so-called alkaptonuric urine is due to this acid. Garrod3considers alkaptonuria as an inborn error of metabolism which is present at birth. When first voided, the urine of an alkaptonuric person appears of normal color but after contact with air undergoes a change through various shades of brown to actual blackness. The addition