A pterygium is a growth of white tissue onto the cornea. It’s commonly caused by excessive ultraviolet (UV) light exposure, and/or chronic irritation from dust and wind. Wearing sunglasses with 100% UV protection can help to protect against these. Pterygia can interfere with vision if they grow far enough onto the cornea. Pterygia can be removed surgically if they begin to cause irritation or begin to interfere with visual acquity.