Arcus senilis (or Arcus senilis corneae. Latin: senile bow) is a peripheral corneal opacity caused by a deposition of phospholipid and cholesterol granules in the corneal stroma (or substantia propria). It typically appears bilaterally and symmetrically as a partial or complete whitish arc highly visible over the iris. It is most often found in the elderly, hence the name. It can be a sign of disturbance in lipid metabolism, an indicator of conditions such as hypercholesterolemia, hyperlipoproteinemia or hyperlipidemia. A unilateral arcus is a sign of carotid artery disease or ocular hypotony.

In younger individuals the condition is called Arcus juvenilis.