A Kayser-Fleischer ring is a rim of brownish green pigment seen in the periphery of the cornea. It signifies excessive deposition of copper in Descement's membrane. The upper pole is affected more frequently than the lower.
Kayser-Fleischer rings are noted in 90% of patients with Wilson's disease and occasionally, in patients with prolonged cholestasis or cryptogenic cirrhosis.
The ring is noted most easily in patients with blue eyes. In other patients, slit-lamp examination may be required.