Corneal Arcus
Corneal Arcus or Arcus senilis appears as a white, gray, or blue ring or arc around the cornea of the eye. The condition is usually seen in older adults but can affect people of all ages, even appearing at birth. Arcus senilis is generally harmless, and an involutional change modified by genetic factors. However, arcus is sometimes indicative of hyperlipidoproteinemia (involving low-density lipoproteins) with elevated serum cholesterol, especially in patients under 40 years of the age.

Causes of corneal arcus
Arcus is a deposition of lipid in the peripheral corneal stroma. Cholesterol and triglycerides are two types of fats in your blood. Some of the lipids in your blood come from foods you eat, such as meat and dairy products. Your liver produces the rest. Lipid deposition starts at the inferior and superior poles of the cornea and in the late stages encircle the entire circumstances. Arcus senilis is more common in men than in women. In people under age 40, arcus senilis is often due to an inherited condition and in rare cases, children are born with arcus senilis ( arcus juvenilis).

Arcus senilis can also appear in people with Schnyder central crystalline dystrophy. This rare, inherited condition causes cholesterol crystals to deposit on the cornea.

Symptoms
A person with arcus senilis may develop:

A white, gray, or blue circle around the cornea of the eye.
The circle or arc will have a sharp outer border but a blurred inner border.
If someone has an arc, the lines could grow to form a complete circle in front of the iris.
The presence of corneal arcus in patients younger than 40 year-old warrants evaluation for systemic lipid abnormalities.
Unilateral arcus is a rare condition associated with contra lateral artery disease or ocular hypotony. Usually it is an asymptomatic condition and does not affect your vision.

Diagnosis
Eye examination performed by eye doctor can diagnose arcus senilis. A slit lamp microscope is a very helpful tool to evaluate eye thoroughly. A special eye drop is used to widen the pupil of the patient. Once the eye drops works, ophthalmologist can inspect all parts of the eye with back of the eye as well for any disease. In arcus, thickness of the vessels increases due to fat deposition. Surgeon has to look for signs of atherosclerosis also, which is a condition where arteries become clogged with fatty substances.

A blood test will determine whether someone has high cholesterol. If they do, they may be prescribed medicine or advised on a suitable diet and exercise program to lower the cholesterol in their blood.

How corneal arcus is managed?
The good news is, you don’t need to treat arcus senilis. It typically affects both eyes, but in some cases only one eye has a grayish arc around the cornea, which may be a sign of poor blood circulation.

Eating healthy foods and exercising regularly are some good ways to keep your eyes healthy. We recommend wearing sunglasses with 100% UV protection when outdoors and safety goggles when doing hazardous tasks as well.

If arcus senilis is a sign of high cholesterol, a doctor may recommend a diet that is low in saturated fats and high in fruit, vegetables, and fiber.

If lipid levels are not controlled by diet and exercise are not enough, several medications can help lower your lipid levels:

Statin drugs block a substance your liver uses to make cholesterol. These drugs include atorvastatin, fluvastatin, pravastatin and rosuvastatin.
Bile acid binding resins force your liver to use more cholesterol to produce digestive substances called bile acids. This leaves less cholesterol in your blood. These drugs include cholestyramine, colesevelam and colestipol.
Cholesterol absorption inhibitors like ezetimibe reduce your body’s absorption of cholesterol.
Drugs may be used to lower triglyceride levels:
Fibrates reduce production of lipids in your liver and increase the removal of triglycerides from your blood.
Niacin reduces the production of lipids by your liver.
Increased exercise and quitting smoking can also help.
Possible complications
Arcus senilis alone is not known to have any complications unless it is a sign of high cholesterol. High levels of cholesterol in a person’s blood can cause significant problems, such as coronary artery disease or cardiovascular disease.

Follow-Up
Arcus senilis may sometimes appear as a white ring around the iris due to calcium deposits on the circumference of the cornea, where the white section of your eye (the sclera) and the colored part (the iris) meet (called the limbus). When the deposits consist of calcium, the limbus appears milky and may indicate tissue damage that needs correction.

The blue (or sometimes gray) ring around the iris often is associated with high cholesterol and triglycerides. In turn, this may be an indicator of heart condition that yor are more prone to heart attacks and strokes. When this condition appears in people younger than 60 years old, regular blood tests are normally recommended to monitor elevated lipid levels.

In few other cases, when corneas become opaque, due to genetic mutation it could be from a lowered high-density lipoprotein (HDL) cholesterol level. This condition can result in other eye problems. Principally, this opacification may be related to deficient levels of lecithin cholesterol acyl transferase (LCAT). LCAT is an enzymatic protein responsible for converting free cholesterol into cholesteryl ester.

Cholesterol ester, is then separated into the nucleus of the lipoproteins to produce a synthetic high-density lipoprotein (HDL) chain. This reaction is forced one way, since the deposits are removed from the exterior. So the enzyme is attached to both HDLs and low-density lipoproteins (LDLs) in blood plasma.

This process can result in the manifestation of fish eyes, and it is actually called “fish eye disease.� Corneal opacification can also result from mutations in another HDL protein, the adenosine triphosphate-binding protein ABCA1.

Just because you are younger than 40 and have arcus does not mean you absolutely have elevated lipid levels, but at a very minimum, it is recommended that you have them checked.

Unilateral corneal arcus may be associated with vascular or inflammatory etiologies.

Important Reminder: This information is only intended to provide guidance, not a definitive medical advice. Please consult eye doctor about your specific condition. Only a trained, experienced board certified eye doctor can determine an accurate diagnosis and proper treatment.