Kayser-Fleischer rings are dark rings that appear to encircle the iris

Iris (anatomy)

The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...

 of the eye

Human eye

The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...

. They are due to copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

 deposition as a result of particular liver diseases. They are named after Dr Bernhard Kayser

Bernhard Kayser

Bernhard Kayser was a German ophthalmologist.Kayser-Fleischer rings are named after him.-References:...

 and Dr Bruno Fleischer

Bruno Fleischer

Bruno Fleischer was a German doctor.Kayser-Fleischer rings and Fleischer rings are named for him.-Further reading:...

, the German

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 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.

Detection

As Kayser-Fleischer rings do not cause any symptoms, it is common for them to be identified during investigations for other medical conditions. In certain situations, they are actively sought; in that case, the early stages may be detected by slit lamp

Slit lamp

The slit lamp is an instrument consisting of a high-intensity light source that can be focused to shine a thin sheet of light into the eye. It is used in conjunction with a biomicroscope...

 examination before they become visible to the naked eye.

Appearance

The rings, which consist of copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

 deposits where the cornea

Cornea

The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is...

 meets the sclera

Sclera

The sclera , also known as the white or white of the eye, is the opaque , fibrous, protective, outer layer of the eye containing collagen and elastic fiber. In the development of the embryo, the sclera is derived from the neural crest...

, in Descemet's membrane

Descemet's membrane

Descemet's membrane is the basement membrane that lies between the corneal proper substance, also called stroma, and the endothelial layer of the cornea. It is composed of a different kind of collagen than the stroma. The endothelial layer is located at the posterior of the cornea...

, first appear as a crescent at the top of the cornea. Eventually, a second crescent forms below, at 6 o'clock, and ultimately completely encircles the cornea.

Associations

Kayser-Fleischer rings are a sign of Wilson's disease

Wilson's disease

Wilson's disease or hepatolenticular degeneration is an autosomal recessive genetic disorder in which copper accumulates in tissues; this manifests as neurological or psychiatric symptoms and liver 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

Basal ganglia

The basal ganglia are a group of nuclei of varied origin in the brains of vertebrates that act as a cohesive functional unit. They are situated at the base of the forebrain and are strongly connected with the cerebral cortex, thalamus and other brain areas...

 of the brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

, liver cirrhosis

Cirrhosis

Cirrhosis is a consequence of chronic liver disease characterized by replacement of liver tissue by fibrosis, scar tissue and regenerative nodules , leading to loss of liver function...

, splenomegaly

Splenomegaly

Splenomegaly is an enlargement of the spleen. The spleen usually lies in the left upper quadrant of the human abdomen. It is one of the four cardinal signs of hypersplenism, some reduction in the number of circulating blood cells affecting granulocytes, erythrocytes or platelets in any...

, involuntary movements, muscle rigidity, psychiatric disturbances, dystonia

Dystonia

Dystonia is a neurological movement disorder, in which sustained muscle contractions cause twisting and repetitive movements or abnormal postures. The disorder may be hereditary or caused by other factors such as birth-related or other physical trauma, infection, poisoning or reaction to...

 and dysphagia

Dysphagia

Dysphagia is the medical term for the symptom of difficulty in swallowing. Although classified under "symptoms and signs" in ICD-10, the term is sometimes used as a condition in its own right. Sufferers are sometimes unaware of their dysphagia....

. The combination of neurological symptoms, a low blood ceruloplasmin

Ceruloplasmin

Ceruloplasmin is a ferroxidase enzyme that in humans is encoded by the CP gene.Ceruloplasmin is the major copper-carrying protein in the blood, and in addition plays a role in iron metabolism. It was first described in 1948...

 level and KF rings is diagnostic of Wilson's disease.

Other causes of KF rings are cholestasis

Cholestasis

In medicine, cholestasis is a condition where bile cannot flow from the liver to the duodenum. The two basic distinctions are an obstructive type of cholestasis where there is a mechanical blockage in the duct system such as can occur from a gallstone or malignancy and metabolic types of...

 (obstruction of the bile duct

Bile duct

A bile duct is any of a number of long tube-like structures that carry bile.Bile, required for the digestion of food, is excreted by the liver into passages that carry bile toward the hepatic duct, which joins with the cystic duct to form the common bile duct, which opens into the intestine.The...

s), primary biliary cirrhosis

Primary biliary cirrhosis

Primary biliary cirrhosis, often abbreviated PBC, is an autoimmune disease of the liver marked by the slow progressive destruction of the small bile ducts within the liver. When these ducts are damaged, bile builds up in the liver and over time damages the tissue. This can lead to scarring,...

and "cryptogenic" cirrhosis (cirrhosis in which no cause can be identified).