Pterygium

It is a triangular fold of membrane from conjunctival layer to the cornea. If advanced, it may lead to blindness.In early stages, a layer of red blood vessels is seen which changes to a white membrane. There is irritation, watering and dimness of vision. It is mostly seen in one eye (rarely in both the eyes) in elderly persons.

Prevention and Precautions
Use coloured glasses which keep the eyes well covered. Avoid strong wind, smoke or dust, eye strain, and constipation. Keep general health good by taking light, vitaminised diet.
The best treatment is surgery by a specialist.