Almost every structure in the eye can sustain damage from the sun. UV light can cause tumors on the eyelids, scar tissue on the conjunctiva (the whites of the eyes), cataracts, and macular degeneration.
A pterygium is scar tissue that starts to grow on the cornea. Generally we measure the pterygium and watch it year to year. If it becomes inflammed we treat it with topical steroid eye drops. If it grows near the visual axis, we have it surgically removed.
Of course, the best protection from the sun is to wear sunglasses with full UV protection. We have the highest quality sunglasses like Oakleys, Maui Jims, Rudy Projects, and Ray Bans, whether you need prescription in your eye glasses or not.