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Pterygium is tissue that grows from the conjunctiva of the eye onto the surface of the cornea.

Causes, incidence, and risk factors

A pterygium is a nonmalignant growth of the conjunctiva (overlying skin around the eye). Most frequently, it grows onto the cornea from the conjunctiva on the inner side of the eye. Less often, it can also occur on the outer side of the cornea.

One or both eyes may be involved. The cause is unknown, but it is more frequent in people with excess outdoor exposure to sunlight and wind, such as those who work outdoors.

Risk factors are exposure to sunny, dusty, sandy, or windblown areas. Farmers, fishermen, and people living near the equator are often affected. Pterygium is rare in children.


The primary symptom of a pterygium is a painless area of elevated white tissue with blood vessels on the inner and/or outer edge of the cornea

Signs and tests

A physical examination of the eyes and eyelids confirms the diagnosis. Special tests are usually not necessary.


No treatment is required unless the pterygium begins to obstruct vision; then it should be surgically removed. Protective glasses and a hat with a brim should be worn to prevent recurrences.

Expectations (prognosis)

Most pterygia cause no problem and need no treatment. If pterygium encroaches on the pupillary area of the cornea, results are usually good after removal.


Recurrence after removal.

Calling your health care provider

People with pterygium should be seen by an ophthalmologist annually, so that encroachment on the pupil can be recognized and treated before interference with vision.

Call for an appointment with your ophthalmologist if you have had a pterygium in the past and symptoms recur.


Eye protection from ultraviolet light may have a preventive effect.

Update Date: 12/24/2002

Raymond S. Douglas M.D., Ph.D. Department of Ophthalmology, UCLA Medical Center, Los Angeles, CA. Review provided by VeriMed Healthcare Network.

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Last updated: Tue, 06 Jan 2009 00:20:03 GMT