Wilson's disease
This Brownish-yellow ring visible around the corneo-scleral junction (limbus) is a very characteristic feature of Wilson's disease. Wilson's disease is a rare inherited disorder that causes too much copper to accumulate in your liver, brain and other vital organs. Copper plays a key role in the development of nerves, bones, collagen and the skin pigment melanin. Normally, copper is absorbed from your food, and any excess is excreted through bile — a substance produced in your liver.In people with Wilson's disease, copper isn't eliminated properly and instead accumulates, possibly to a life-threatening level.Kayser–Fleischer rings is the single most important diagnostic sign in Wilson's disease (found in 95% of patients). The rings consist of copper deposits appear where the cornea meets the sclera, in Descemet's membrane.