After a recent exam, a friend of mine was told he has "rust rings" in his eyes. The doctor suggested that it was a degenerative condition, but did not provide further information. What could cause pigmented corneal rings? Is Wilson's disease a likely diagnosis? My friend is almost 50 and has no other symptoms.

E.M.

There are several different conditions that lead to the development of "rings" in the eye. One of those is the disorder that you mention: Wilson's disease, or hepatolenticular disorder.

Wilson's disease is an inherited condition that leads to the accumulation of high levels of copper in the body. Copper, a trace mineral found in many foods, is essential to our health. Healthy people excrete any extra copper. However, in people with Wilson's disease, copper gradually builds up, beginning at birth. This excess copper is deposited in the liver and brain, causing inflammation of the liver (hepatitis) and neurologic changes. Symptoms, which usually appear when people are in their teens, include jaundice, tremors, difficulty walking and psychiatric illness. It is extremely important to diagnose Wilson's disease as early as possible, because excess copper can permanently damage the liver, leading to death. If Wilson's disease is suspected, doctors should perform a blood test to measure the level of ceruloplasmin and a urine test to measure copper levels.

Besides the brain and the liver, another part of the body where excess copper may be deposited is in the cornea of the eye. These copper deposits result in a gray ring, which doctors refer to as a Kayser-Fleischer ring. Although this ring occurs only in people with Wilson's disease, it may not appear until late in the disease. Although a Kayser-Fleischer ring will often fade after medical intervention to reduce copper levels, disappearance of such rings is not regarded as a good indicator of successful treatment of the condition.

Wilson's disease requires lifelong treatment. Zinc-acetate therapy has been shown to effectively reduce copper levels by blocking the absorption of copper in the gastrointestinal tract.

That said, it's important to point out that you stated that your friend was diagnosed with a "rust ring." A rust ring usually occurs when a piece of metal falls into the eye and lodges in the cornea. This condition occurs very frequently, especially among metalworkers who don't wear safety goggles. Once a piece of metal lodges in the cornea, metal particles will start to leach into the surrounding corneal tissue. When the actual piece of metal is removed from the cornea, often a small amount of residual metal is left behind -- and that material forms the rust ring. A rust ring that is not in the center of the cornea can often be safely left as is without danger of vision loss or other complications.