Arcus senilis

Arcus (ar·cus) (ahr´kəs) pl. ar´cus [L. “a bow”] [TA] arch: a general term used in anatomical nomenclature to designate any structure having a curved or bowlike outline.A. cor´neae , A. cornea´lis or Arcus senilis (or Arcus senilis corneae) is a white or gray opaque ring in the corneal margin peripheral (corneal) opacity, present at birth, or appearing later in life, and becoming quite frequent in those over 50; it results from cholesterol deposits in or hyalinosis of the corneal stroma and may be associated with ocular defects or with familial hyperlipidemia.
See more at Wikipedia.org...

Arcus senilis, n an opaque, grayish-white ring at the periphery of the cornea occurring in older adults. [more]Arcus senilis - Community and Resources

Noun
1. an arc-shaped whitish deposit sometimes seen in the cornea
(synonym) arcus
(hypernym) cornea

A cloudy opaque arc or circle around the edge of the eye, often seen in the eye of the elderly.

noun
arch
arcus senilis = grey ring round the cornea, found in old people

ARCO SENILE. GERONTOXON