Kayser-Fleischer rings (KF rings) are dark brown or greenish brown rings of copper deposits which appear around the iris of the eye. They consists of copper deposits in Descemet’s membrane, extending into the trabecular meshwork. Kayser-Fleischer rings can be either the result of particular liver diseases, or a sign of Wilson's disease, which involves abnormal copper handling by the liver resulting in copper accumulation in the body and is characterised by abnormalities of the basal ganglia of the brain, liver cirrhosis, splenomegaly, involuntary movements, muscle rigidity, psychiatric disturbances, dystonia and dysphagia. They are named after Dr Bernhard Kayser and Dr Bruno Fleischer, the German doctors who first described them in 1902 and 1903. Initially thought to be due to the accumulation of silver, they were first demonstrated to contain copper in 1934.