A pterygium can usually be seen as a fleshy, pink growth on the white of the eye, and may occur in one eye or both. They occur between the eyelids, most often in the corner of the eye, close to the nose, and extend onto the cornea.
Many people with a pterygium feel as if there is something in their eye. Symptoms also include dry eyes, irritation, inflammation and redness. They can also make it more difficult or uncomfortable to wear contact lenses.
If the pterygium extends onto the cornea far enough it can cause blurred vision as the curvature of the cornea is altered, and can also obscure vision.
Causes of pterygia
The main cause is almost certainly lifetime sun exposure - UV light. People who live in hot, dry, sunny regions and spend a lot of time outdoors have a higher chance of developing a pterygium than others. The risk is also increased by not wearing sunglasses or a sun hat.
Sports people such as sailors, surfers and skiers also have a high incidence because of the high levels of reflected UV light they encounter. Pterygia are also more common in areas where there is ozone layer depletion, such as New Zealand.
Pterygia usually occur in people aged 20 to 50, and are more common in men, probably due to an increased likelihood of outdoor work environment.
A pinguecula (plural pingueculae) is very similar to a pterygium, and the two are often confused. However, a pinguecula occurs only on the conjunctiva (the thin, protective membrane that covers the surface of the eye), and will not grow across the cornea.
It has very similar symptoms to a pterygium. It usually appears as a creamy-coloured or chalky growth on the white of the eye, between the eyelids. A pinguecula will also normally occur in the corner of the eye, near the nose, and can affect one eye or both.
Just like a pterygium, a pinguecula can cause irritation, as well as difficulty wearing contact lenses. However, a pinguecula cannot grow across the cornea, and therefore will not affect vision. In some cases though, a pinguecula can become a pterygium, involving the cornea.
Causes of pingueculae
Just like pterygia, pingueculae generally occur between the ages of 20 and 50. They are also thought to be caused by environmental factors, such as climate, dust and UV light.
Treating a pterygium or pinguecula
There a number of different treatments for a pterygium or pinguecula. Normally, pterygium surgery will only be undertaken if the pterygium has troublesome symptoms, or is affecting vision. Otherwise, management with eye drops is often effective.
Pingueculae are rarely surgically removed, and are usually treated with eye drops. However, if the pinguecula turns into a pterygium, surgery may be the best course.
Following pterygium removal with conjunctival grafting.