Pterygium is a growth of tissue from the white of the eye that grows across the cornea.
This overgrowth is considered to be caused by excessive exposure to sunlight, but an association with some other factor is probably necessary because most people do not develop this problem even if they are in the sunshine. Mineral deficiencies, especially zinc, may be relevant.
Mineral analysis and correction of any deficiencies may halt the progress.
Dark glasses should be warn in extremes of sunlight by those who have a tendency to develop this condition.
Surgical removal is a simple procedure for an ophthalmic surgeon.