A pterygium is a pinkish-colored patch of tissue that grows on the cornea. Pterygia can potentially grow large enough to seriously obstruct vision, but this is a rare occurrence. More often, it is a cosmetic concern, since the pterygia can be seen when it becomes red and inflamed from dust or sunlight. Eye lubricants are usually an effective treatment for smaller pterygia, since they reduce the swelling and redness, and thus their appearance. When they grow large enough to obstruct vision, however, surgery may be needed.