Corneal arcus Anterior embryotoxon Gerontoxon A gray opaque line which surrounds the margin of the cornea caused by lipid deposits. HP:0100741 Arcus lipoidis HP:0001084 UMLS:C0003742 Arcus juvenilis SNOMEDCT_US:111522004 UMLS:C0339268 A hazy, grayish-white ring about 2 mm in width located close to but separated from the limbus (the corneoscleral junction). Corneal arcus generally occurs bilaterally, and is related to lipid deposition in the cornea. Corneal arcus can occur in elderly persons as a part of the aging process but may be associated with hypercholesterolemia in people under the age of 50 years. SNOMEDCT_US:231925004 Arcus senilis SNOMEDCT_US:231924000 Corneal annulus Peripheral opacification of the cornea