The conjunctiva is a clear, thin layer of tissue that covers the white part of the eye. Pterygia are a direct result of degeneration of this conjunctival tissue. A pterygium is a fleshy triangular shaped tissue located on the horizontal meridian of the white part of the eye. As this conjunctival degeneration progresses, its growth slowly extends onto the front clear surface of the eye, the cornea.
The cause for ptergia is not completely understood. However, there seems to be a relationship between those who have ptergia and the environments in which they live or work. Common causes are thought to be environment that are dirty, dusty, smoky, windy and environments that expose people to large amounts of sunlight or ultraviolet light. All spectacle eyewear corrections should contain an ultraviolet coating to help prevent further irritation.
In addition, certain tasks decrease the normal blink rate of the eye, e.g., computer use. A decrease in the blink rate increases evaporation of the tears from the surface of the eye, causing decreased lubrication. Decreased lubrication causes mechanical irritation of the eye, which is thought to be a contributory cause of this type of degeneration.
Ptergia are typically not dangerous. They are characterized by a whiteish or yellowish appearance.
Symptoms include a gritty or a sandy sensation upon blinking. Since they contain numerous blood
vessels, the eye will look much redder than normal. Treatment may involve the use of ocular
decongestants or in some cases, mild topical steroids. If the ptergium continues to grow towards the center of the cornea, threatening vision, or if it presents a cosmetic problem, it may require surgical intervention and removal. This condition should be monitored on a regular basis so that measurements can be taken to evaluate any change in growth or change in position.
