Arcus senilis (AS), also known as gerontoxon, arcus lipoides, arcus corneae, corneal arcus, arcus adiposus, or arcus cornealis, are rings in the peripheral

cornea The cornea is the transparency (optics), transparent front part of the eyeball which covers the Iris (anatomy), iris, pupil, and Anterior chamber of eyeball, anterior chamber. Along with the anterior chamber and Lens (anatomy), lens, the cornea ...

. It is usually caused by cholesterol deposits, so it may be a sign of high cholesterol. It is the most common peripheral

corneal opacity Corneal opacification is a term used when the human cornea loses its transparency. The term corneal opacity is used particularly for the loss of transparency of cornea due to scarring. Transparency of the cornea is dependent on the uniform diamete ...

, and is usually found in the elderly where it is considered a benign condition. When AS is found in patients less than 50 years old it is termed arcus juvenilis. The finding of arcus juvenilis in combination with

hyperlipidemia Hyperlipidemia is abnormally high levels of any or all lipids (e.g. fats, triglycerides, cholesterol, phospholipids) or lipoproteins in the blood. citing: and The term ''hyperlipidemia'' refers to the laboratory finding itself and is also use ...

in younger men represents an increased risk for cardiovascular disease.

Pathophysiology

AS is caused by leakage of

lipoprotein A lipoprotein is a biochemical assembly whose primary function is to transport hydrophobic lipid (also known as fat) molecules in water, as in blood plasma or other extracellular fluids. They consist of a triglyceride and cholesterol center, sur ...

s from limbal capillaries into the corneal stroma. Deposits have been found to consist mostly of

low-density lipoprotein Low-density lipoprotein (LDL) is one of the five major groups of lipoprotein that transport all fat molecules around the body in extracellular water. These groups, from least dense to most dense, are chylomicrons (aka ULDL by the overall density ...

(LDL). Deposition of lipids into the cornea begins at the superior and inferior aspects, and progresses to encircle the entire peripheral cornea. The interior border of AS has a diffuse appearance, while the exterior border is well demarcated. The clear space between the exterior border and the

limbus Limbus (Lat. "edge, boundary") may refer to: * Corneal limbus, the border of the cornea and the sclera (the white of the eye) * Limbus of fossa ovalis, in the heart * Limbus 3 and Limbus 4, two line-ups of a German avant-garde musical group * ...

is called the interval of Vogt. Bilateral AS is a benign finding in the elderly, but it can be associated with hyperlipidemia in patients less than 50 years old. Bilateral AS may also be caused by increased levels of

free fatty acids In chemistry, in particular in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, f ...

in the circulation secondary to alcohol use. Unilateral AS can be associated with contralateral

carotid artery stenosis Carotid artery stenosis is a narrowing or constriction of any part of the carotid artery, carotid arteries, usually caused by atherosclerosis. Signs and symptoms The common carotid artery is the large artery whose Common carotid artery#Clinical ...

or decreased

intraocular pressure Intraocular pressure (IOP) is the fluid pressure inside the eye. Tonometry is the method eye care professionals use to determine this. IOP is an important aspect in the evaluation of patients at risk of glaucoma. Most tonometers are calibrated t ...

in the affected eye. As these are serious medical conditions, unilateral AS should be examined by a physician.

Diagnosis

AS is usually diagnosed through visual inspection by an

ophthalmologist Ophthalmology (, ) is the branch of medicine that deals with the diagnosis, treatment, and surgery of eye diseases and disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Following a ...

optometrist Optometry is the healthcare practice concerned with examining the eyes for visual defects, prescribing corrective lenses, and detecting eye abnormalities. In the United States and Canada, optometrists are those that hold a post-baccalaureate f ...

using a

slit lamp In ophthalmology and optometry, a slit lamp is an instrument consisting of a high-intensity light source that can be focused to shine a thin sheet of light into the eye. It is used in conjunction with a biomicroscope. The lamp facilitates an ...

Differential diagnoses

Several conditions can have a similar color and appearance. *

Limbus sign The limbus sign is a ring of dystrophic calcification evident as a "milky precipitate" (i.e. abnormal white color) at the corneal limbus. The corneal limbus is the part of the eye where the cornea (front/center) meets the sclera (white part of th ...

is caused by

dystrophic calcification Dystrophic calcification (DC) is the calcification occurring in degenerated or necrotic tissue, as in hyalinized scars, degenerated foci in leiomyomas, and caseous nodules. This occurs as a reaction to tissue damage, including as a consequenc ...

at the corneal limbus, and can be confused with AS in geriatric populations. * Anterior embryotoxon is a congenital widening of the

corneal limbus The corneal limbus (''Latin'': corneal border) is a highly vascularized and pigmented zone between the cornea, conjunctiva, and the sclera (the white of the eye) that protects and heals the cornea. The cornea is composed of three primary cell ty ...

. * Posterior embryotoxon is a congenital thickening and anterior displacement of

schwalbe's line Schwalbe's line is the anatomical line found on the interior surface of the eye's cornea, and delineates the outer limit of the corneal endothelium layer. Specifically, it represents the termination of Descemet's membrane. In many cases it can b ...

. Other conditions with similar appearance, but differing in color are

limbal ring A limbal ring is a dark ring around the iris of the eye, where the sclera meets the cornea. It is a dark-colored manifestation of the corneal limbus resulting from optical properties of the region. The appearance and visibility of the limbal ...

, and

Kayser–Fleischer ring Kayser–Fleischer rings (KF rings) are dark rings that appear to encircle the cornea of the human eye, eye. They are due to copper deposition in the Descemet's membrane as a result of particular liver diseases. They are named after Germany, Germa ...

Treatment

In the elderly, arcus senilis is a benign condition that does not require treatment. The presence of an arcus senilis in males under the age of 50 may represent a risk factor for cardiovascular disease, and these individuals should be screened for an underlying lipid disorder. The opaque ring in the cornea does not resolve with treatment of a causative disease process, and can create cosmetic concerns.

Epidemiology

In men, AS is increasingly found starting at age 40, and is present in nearly 100% of men over the age of 80. For women, onset of AS begins at age 50 and is present in nearly all females by age 90.

Risk factor for cardiovascular disease

AS is not an independent predictor of cardiovascular disease, as demonstrated by a prospective cohort study of 12,745 Danes aged 20-93 followed up for an average of 22 years. The presence of AS in men less than 50 years old(arcus juvenilis) in combination with an underlying condition causing

has been shown to significantly increase the

relative risk The relative risk (RR) or risk ratio is the ratio of the probability of an outcome in an exposed group to the probability of an outcome in an unexposed group. Together with risk difference and odds ratio, relative risk measures the association bet ...

of mortality from

cardiovascular disease Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina, heart attack), heart failure, hypertensive heart disease, rheumati ...

and

coronary artery disease Coronary artery disease (CAD), also called coronary heart disease (CHD), or ischemic heart disease (IHD), is a type of cardiovascular disease, heart disease involving Ischemia, the reduction of blood flow to the cardiac muscle due to a build-up ...

, as demonstrated by a study following 6,069 Americans aged 30-69 for an average of 8.4 years. The presence of AS in men less than 50 years old (arcus juvenilis) in conjunction with

xanthoma A xanthoma (pl. xanthomas or xanthomata) (condition: xanthomatosis) is a deposition of yellowish cholesterol-rich material that can appear anywhere in the body in various disease states. They are cutaneous manifestations of lipidosis in which lip ...

s on the achilles tendon has been linked to the presence of

atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis, characterized by development of abnormalities called lesions in walls of arteries. This is a chronic inflammatory disease involving many different cell types and is driven by eleva ...

in the coronary arteries and aorta by computed tomography.

References

{{DEFAULTSORT:Arcus Senilis Disorders of sclera and cornea