What is pterygium?

Pterygium (pterygia plural)

The cornea (crystal window of the eye) is 12mm wide and overlies the iris (coloured part of the eye) which is seen through the transparent cornea.  The cornea is surrounded by the sclera (the white of the eye). Overlying the white of the eye is the conjunctiva (a transparent filmy tissue like the membrane lining the mouth).

A pterygium (“wing of tissue”) is an overgrowth of tissue from the white of the eye over onto the cornea (crystal window of the eye). It normally presents on the “nose” side of the eye although occasionally, in less than 1 percent of cases, it may come from the “ear” side.

It usually presents in patients over the age of 20 or 30 years although it has been known to occur during teenage years.

This is not a cancer and is a localised disturbance on the surface of the eye.

Usually a pterygium will remain stationary after a period of growth during which time it may extend 1, 2, 3 millimetres or more onto the cornea. It is impossible for anyone to predict whether a particular pterygium is likely to grow further and over what time.  Very occasionally it may cross the line of vision.

In a small percentage of cases, a pterygium may grow on both eyes of the same individual. In very rare cases, an individual may have two pterygia on each eye.