A pterygium is a wing-shaped growth on the nasal aspect of the conjunctiva (the white part of the eye). Pterygiums can grow quite large and can induce astigmatism and irregularities in the cornea. Pterygia can be treated with artificial tear lubricants and other eye drops if they become inflamed or enlarged. Large pterygiums which grow over the cornea or induce high amounts of astigmatism can be removed and cosmesis and regularity can often be restored successfully.