Arcus senilis is a depositing of phospholipid and cholesterol in the peripheral cornea in patients over the age of 60 which appears as a hazy white, grey, or blue opaque ring (peripheral corneal opacity). Arcus is common and benign when it is in elderly patients. However, if arcus appears in patients less than 50 years old, it is termed "arcus juvenilis" and is associated with abnormally high cholesterol in the body with increased risks for cardiovascular disease.
Arcus may also present as a white ring, which is visible in front of the periphery of the iris.
Arcus results from cholesterol deposits in or hyalinosis of the corneal stroma, and may be associated with ocular defects or with familial hyperlipidemia. It is common in the apparently healthy middle aged and elderly; a prospective cohort study of 12,745 Danes followed up for a mean of 22 years found that it had no clinical value as a predictor of cardiovascular disease.
Arcus can be a sign of disturbance in lipid metabolism, an indicator of conditions such as hypercholesterolemia, hyperlipoproteinemia or hyperlipidemia.
Unilateral arcus is a sign of decreased blood flow to the unaffected eye, due to carotid artery disease or ocular hypotony.
Arcus is usually diagnosed through visual inspection by an ophthalmologist or optometrist using a biomicroscope.
Arcus senilis can be confused with the limbus sign, which reflects calcium rather than lipid deposits. Anterior embryotoxon is a benign, congenital, elongation of the sclera-cornea transition zone which is present at birth and has a similar appearance to arcus juvenilis.
It is also called arcus adiposus, arcus corneae, arcus juvenilis (when it occurs in individuals younger than 50 years), arcus lipoides corneae or arcus cornealis; sometimes a gerontoxon.