The Kayser-Fleischer ring is found in many cases of Wilson disease, usually when neuropsychiatric signs are present (and less so if the disease only affects the liver). Although a slit-lamp exam is the most sensitive way of detecting them, they are occasionally seen with (your) naked eye.
The ring itself comes from fine, pigmented granular deposits of copper in Descemet’s membrane in the cornea, close to the endothelial surface; copper is primarily deposited in a granular complex with sulfur, which gives the ring its color. Look for the rings at the inferior and superior poles of the cornea.
Don’t forget some of the diagnostic laboratory clues for Wilson disease: low alkaline phosphatase, low serum ceruloplasmin, high urine copper and evidence of hemolytic anemia (as copper causes red cell lysis in the more fulminant cases of the disease).