If the bump appears only on the white part of the eye, it is called a pinguecula. If it appears to "grow" onto the cornea, forming a winglike structure, it is called a pterygium from the Greek word for wing (pterygion).
Although the causes of these lesions are not completely understood, prolonged exposure to ultraviolet and infrared radiation from sunlight has been implicated. Other environmental irritants, such as dust and wind, may play a role as well. People who spend considerable time in the sun are much more likely to have pingueculae or pterygia than indoor folks. Susceptible groups include individuals who work outdoors such as farmers and fishermen or those who engage in outdoor activities such as golfing and gardening.
First, vision may be affected by a pterygium large enough to involve the cornea's center visual zone or that causes astigmatism. Surgery may be able to improve the clarity of the optical center and limit excessive or irregular astigmatism.
Second, a pterygium (rarely a pinguecula) may be unsightly and cosmetically objectionable. Surgery can reduce the size of a fleshy pterygium, but complete elimination is often not possible.
Third, either a pinguecula or pterygium may cause excessive discomfort due to dryness or a chronic foreign body sensation. Surgery usually improves comfort, but sometimes irritating symptoms may remain.
Surgery can be performed as an outpatient procedure with local anesthesia; and pain is uncommon.