Pterygium

A pterygium is a non-cancerous growth that starts in the of 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.

 Causes
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.

Symptoms

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 grows extends far enough onto the cornea.

Treatment

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