Its very common in people, who work more in the dusty envirounment and sun exposure. It will not cause any serious problem to the eye. but cosmatical it look bad, eye become red often. for me my opthalmologist adviced just a regular use of sun glasses within 6 month it disappers, you can also try using sun glassess.
Pterygium is a fleshy growth of the conjunctiva caused by exposure to ultraviolet rays.It can be corrected surgically.For more details visit
http://sites.google.com/site/eyediseases/