Pterygium is a vascular pink tissue that can grow from the conjunctiva onto the cornea. If it grows into the line of vision (over the pupillary aperture), it can interfere with vision. Pterygium are most commonly found to originate from on the inner (nasal) surface of the eye, and extend toward the the pupil. They can also occur the on the temporal (towards the ear) side of the eye.

Pterygium are more common in countries near to the equator, therefore long-term exposure to sunlight, particularly ultraviolet (UV) rays have been a suggested cause. In addition, others believe that chronic eye irritation may play an important role. Therefore, pterygium occur more often in people who spend time outdoors, particularly in sunny climates.

Pterygium are benign (not malignant) tumors. Hence pterygium do not invade the eye, sinuses or brain.

If a pterygium becomes red and irritated, lubricating eye drops or ointments can be placed onto the eye as to reduce the inflammation. Rarely, steroid drops may be prescribed.

Pterygium are surgically removed when they affect sight, grow such that your eye care professional expects it to impair vision, or if it is cosmetically unacceptable. Unfortunately, pterygium may return despite proper surgical removal. To help prevent recurrences surface radiation, conjunctival implants (grafts), or chemotherapy medications can be used.