Pterygiums (tur-IJ-ee-um) are growths on the outside of the eye, which usually form in the areas where the eye is most exposed to sunlight and ambient atmosphere.
Pterygiums are triangular, fibrovascular, connective tissue overgrowths of conjunctiva that grow onto the clear cornea. They are not to be confused with cataracts or any other conditions inside the eye. They are believed to possibly have a relationship to exposure to ultraviolet light and therefore, found either on the nasal or temporal side (3 or 9 o’clock position) of the cornea.
Ultraviolet sunlight varies with the geographic latitude in which one lives. People who live by the equator have a greater tendency to develop pterygiums than people who live in the Northern United States or Canada.
There is a belief that the wearing of sunglasses or regular glasses with ultraviolet blockers can decrease the incidence of a pterygium. Pterygiums can be unilateral or bilateral and may progress slowly toward the center of the cornea or may be inactive and not show further growth. When the eye is irritated, the pterygium tends to swell and be more noticeable, red and irritated.
The indications for removal of a pterygium are two-fold. One, if they continue to grow and they appear to be blocking the visual axis and extending further into the clear cornea they should be excised before they cause any visual decrease. The other indication is cosmetic. If these pterygiums become thick and vascular, they can be quite unsightly. They can also be a problem for people who want to wear contact lenses. These growths can also distort vision.
Removing a pterygium requires surgically peeling this growth back off the cornea. When the pterygium is removed, it can at times, grow back relatively rapidly. The recurrence rate has decreased since the use of grafts (autografts – using a patient own conjunctiva or amniograft using preserved processed placental tissue, see AmnioGraft-Bio Tissue, Inc.) and the use of glue Tisseel to attach the graft. Sometimes we use “anti-growth” factor agents like mitomycin to decrease regrowth.
In the immediate post operative period after the pterygium is removed, the eye might feel irritated and scratchy, almost as if there is some sand or gravel in the eye. Frequent instillation of teardrops will help relieve these symptoms.
Though a pterygium is not a serious condition and does not degenerate into anything more serious, their growth can be rapid, cause visual distortion and be a significant cosmetic problem.
Considering that exposure to ultraviolet light can contribute to causing the growth of pterygiums the use of glasses with ultraviolet filters is advisable.
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