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A pterygium is a non-cancerous growth that starts in the clear, thin tissue (conjunctiva) of the eye. This growth covers the white part of the eye (sclera) and extends onto the cornea. It is often slightly raised and contains visible blood vessels. The problem may occur on one or both eyes.


The exact cause is unknown. It is more common in people who have a lot of exposure to sunlight and wind, such as people 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 main symptom of a pterygium is a painless area of raised white tissue that has blood vessels on the inner or outer edge of the cornea. Sometimes the pterygium has no symptoms. However, it may become inflamed and cause burning, irritation, or a feeling like there's something foreign in the eye. Vision may be affected if the growth extends far enough onto the cornea.

Exams and Tests

A physical exam of the eyes and eyelids confirms the diagnosis. Special tests are not needed most of the time.


Treatment is not needed in most cases. Using artificial tears to keep the eyes moist may help prevent a pterygium from becoming inflamed. Mild steroid eye drops can be used to calm inflammation if it occurs. Surgery can be used to remove the growth for cosmetic reasons or if it blocks vision.

Outlook (Prognosis)

Most pterygia cause no problems and do not need treatment. If a pterygium affects the cornea, removing it can have good results.

Possible Complications

Ongoing inflammation can cause a pterygium to grow farther onto the cornea. A pterygium can return after it is removed.

When to Contact a Medical Professional

People with pterygium should be seen by an ophthalmologist each year. This will enable the condition to be treated before it affects vision.

Call your ophthalmologist if you have had a pterygium in the past and your symptoms return.


Taking steps to protect the eyes from ultraviolet light may help prevent this condition. This includes wearing sunglasses and a hat with a brim.


Reddy JC, Juthani V, Fowler PG, Rapuano CJ. Corneal Topography and Tomography. In: Tasman W, Jaeger EA, eds. Foundations of Clinical Ophthalmology. 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013:vol 2; chap 112.

Shields CL, Shields JA. Tumors of the Conjunctiva and Cornea. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013:vol 4; chap 10.

Shtein RM, Sugar A. Pterygium and conjunctival degenerations. In: Yanoff M, Duker JS, eds. Ophthalmology. 4th ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 4.9.

Review Date: 11/5/2014
Reviewed By: Franklin W. Lusby, MD, ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
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