White of the eye overgrowing the iris...?

I have noticed in my travels to second and third world countries that quite a few middle age people have the same eye condition. The white of the eye appears to be overlapping the iris in eiother one or both eyes. What is this called and what causes it?

White of the eye overgrowing the iris...?
You are describing a pterygium. Pronounced -- TER RIDGE' EEE UMM. As you noted it is more common in third world countries and also in the sunbelt states of the United States and other countries. The causes are probably multifactorial but it appears to be more prominent in areas with more wind, sun exposure, and environmental irritants to the eye. The conjunctiva (the clearish white tissue that lies over the white part of the eye) becomes more vascularized and then begins to grow progressively across the anterior surface of the cornea. As long as the pterygium does not enter the optical zone of the cornea there is no danger to loss of sight. But, pterygiums can cause irritation and discomfort not to speak of the consmetic problem. I tend to recommend monitoring as long as there are no significant symptoms and the pterygium is not progressing toward the optical zone. If either of these happens, though, the pterygium should be surgically removed.