What is Arcus?
Arcus is the name for a white, light grey, or blueish ring around the edge of the cornea. It is made of fatty substances (called lipids), mostly cholesterol. The cornea is usually clear and allows the color of your iris beneath it to show through. This ring can make it seem as though your iris is two different colors, but in fact it is a discoloration in the cornea.
Arcus usually begins as a short arc of color along the top and bottom of the cornea. Eventually these may connect and make a complete ring around the cornea.
Who is Likely to Get Arcus?
Arcus is common in people as they age. If these rings begin to appear around middle age or later, they are usually nothing to worry about. A large percentage of adults will eventually develop arcus to some extent. It is most common in men and in African Americans.
If you have a family history of high cholesterol you are more likely to have arcus. But the appearance of arcus in middle age or later does not necessarily mean you have high cholesterol.
Rings Around the Iris Before Middle Age
Colored rings around the iris that begin to appear in childhood or early adulthood are less common. This is referred to as “arcus juvenilis”. Arcus juvenilis can be the sign of high cholesterol or other health problems.
How is Arcus Diagnosed and Treated?
An eye doctor can simply look at your eye with a slit-lamp microscope to diagnose arcus. This condition has no symptoms. It does not cause vision problems, so no ocular treatment is necessary. If a patient is unaware of their cholesterol status, it is advisable for them to follow up with their primary care provider to have cholesterol levels checked. Elevated systemic cholesterol levels can affect the overall health of the entire body, including the eyes. If hypercholesterolemia is confirmed, patients should work with their primary care doctors to bring these levels under control. However, improved control of cholesterol levels will not make arcus disappear.