Arcus senilis is a gray or white arc that appears in the eye above and below the outer cornea. The cornea is the clear, domelike covering over the front of the eye. Eventually, the arc may become a complete ring around the iris. The iris is the colored portion of the eye.

Arcus senilis is common in older adults. It's caused by fatty deposits deep in the edge of the cornea. Arcus senilis doesn't affect vision. It also doesn't need treatment.

When arcus senilis occurs in older adults, it isn't related to high cholesterol. However, an arc or ring around the iris sometimes occurs in younger people who have familial hyperlipidemia. Familial hyperlipidemia is a disorder that is passed down through families. It causes very high levels of low-density lipoprotein cholesterol, the "bad" cholesterol. In people with familial hyperlipidemia, this arc or ring typically occurs before age 45 and is linked to an increased risk of heart disease.