A pinguecula is a raised yellowish white growth next to, but not overlapping, the cornea. This growth can be unsightly, but it typically does not cause any significant problems and does not need to be removed.
A pterygium is a fleshy growth of the conjunctiva that spreads across onto the cornea. Most pterygia do not cause symptoms, but sometimes they cause irritation or distort the shape of the cornea, possibly causing a decrease in vision, and it can also be a cosmetic concern.
To relieve symptoms caused by a pterygium, doctors may prescribe artificial tears or a short period of treatment with corticosteroid drops or ointments. If the symptoms do not lessen, particularly if vision is affected, or they return frequently, the pterygium may be removed surgically. Growth of a pterygium can be slowed with protection from sunlight, such as when wearing sufficiently protective sunglasses (with UV blocking) and/or a hat.