A pterygium is a pinkish, triangular-shaped tissue growth on that invades the cornea. It is an abnormal process in which the conjunctiva (a membrane that covers the white of the eye) grows onto the cornea. Pterygium may be small or grow large enough to interfere with vision, and commonly occurs on the inner corner of the eye.
Pterygium occurs more often in people who spend a great deal of time outdoors, especially in sunny climates. Long-term exposure to sunlight's harmful ultraviolet (UV) rays, and chronic eye irritation from dry, dusty conditions seems to play an important causal role. With newer surgical techniques, such as using conjunctival autografts, recurrence rates have decreased to almost zero percent.