A pterygium (pronounced “ter y gee um”) is small “wing-shaped” fleshy membrane that slowly grows over the cornea. Although it usually grows in the nasal aspect of the eye (closer to the nose), it can grow on the temporal aspect as well, and it is not uncommon to see them cover both sides of the cornea at the same time (kissing pterygia).
It is not exactly clear why they develop, but it is understood that there is a genetic component as well as a history of high exposure to sunlight (people who live in equatorial regions of the earth tend to get them more frequently). Pterygia affect millions of people’s eyes and causes chronic irritation, redness, and tearing. In severe cases, they can cause severe astigmatism and even blindness.
Although regular lubrication with artificial tears and the use of vaso-constrictive eye drops (Naphcon or Visine) helps relieve some of the symptoms of pterygia, they never regress spontaneously and require surgery to avoid worsening symptoms and improving vision.
Pterygia can be surgically removed using local anesthesia only. Once removed, it is very important to cover the area that used to be involved with either a small piece of the conjunctiva (the thin clear skin that covers our eyeballs) from one’s own eye in order to prevent the pterygium from coming back.
A small piece of conjunctiva (the thin clear skin that covers the eye ball) is removed and placed over the area where the old pterygium used to be. Even today, this graft is resected by ophthalmologists using a blade or scissors. This makes the eye bleed profusely and makes the surgery much more difficult, lengthy, and invasive.
Anytime the skin of the eye (conjunctiva) is damaged or excised (e.g., during pterygium surgery), the affected area needs to be covered up in order to avoid pain, irritation, infection, and problems with the underlying sclera (the white skeleton of the eye-ball). To this effect, most eye surgeons have to reconstruct the bare surface of the eye-ball. Oftentimes, a small patch of the eye’s skin (conjunctiva) is borrowed from under the top of the eye as this part is covered by the upper eyelid anyway and doesn’t cause any pain / irritation. This is the best way to reconstruct the eye, but there are instances where this part has either been previously removed or damaged (e.g. during previous pterygium or glaucoma surgery). In such patients, a small patch of a thin processed amniotic membrane can be used to reconstruct the defective area.