The cause of a pterygium is not known. But exposure to ultraviolet light may play some role. Having certain genes may help lead to a pterygium in some people as well. Infection with human papillomavirus may also play a role. But this theory still remains controversial.

Spending a lot of time in the sun may raise your risk. Not using sunglasses may also increase your risk. If someone in your family has had a pterygium, you may be at greater risk as well.

Symptoms are often mild. Many people don't have any symptoms. You are less likely to have symptoms if the growth is small. Some symptoms can include:

• Eye irritation and burning
• Eye dryness
• Eye redness
• Blurred vision (if the growth gets close to the middle of your cornea)
• Restriction of eye movement (this is rare)

Some people don't like the way a pterygium looks. Typically, it is a triangle-shaped growth, but the shape may vary. Some people notice it only after the growth has covered a major part of their cornea and blocks their iris. The growth might be white, pink, or red.

Your doctor can diagnose a pterygium with a health history and eye exam. Your doctor might refer you to an eye doctor for evaluation.

Often, a health history and exam provide enough information for a diagnosis. Your eye doctor will closely examine its growth. This can help to make sure it is not another condition that may need a different treatment. In rare cases, your eye doctor might take a small sample (biopsy) of the pterygium and have it looked at under a microscope to make sure it isn't a cancer growth.

If your pterygium is not causing any symptoms, it won't need treatment. If symptoms develop, your eye doctor might recommend the following:

• Over-the-counter products to help with discomfort, redness, or irritation, such as artificial tears or other lubricating eye drops, gels, or ointments
• Prescription eye drops, gels, or ointments, such as steroid eye drops, if the over-the-counter products don't help
• Surgery

Only surgery can remove your pterygium. But other treatments may help reduce symptoms. Your eye doctor may be more likely to recommend surgery if:

• Your growth is causing vision problems or is getting larger
• You can't move your eye normally
• You have severe eye irritation that won't go away with other treatment
• Your eye's appearance bothers you a lot

Unfortunately, a pterygium will often grow back after surgery to remove it. (This may be more likely if you are under age 40.) Sometimes the growth that comes back causes worse symptoms than the original one. Your eye doctor might find it even harder to remove this new growth. That is why eye doctors don't often advise removing one unless it causes major symptoms.

Your pterygium may be less likely to return if you have other treatments as well as surgery. These treatments, such as MMC (mitomycin C), stop cell growth in the area. And they may help prevent future growth there. A treatment called beta irradiation may also help prevent regrowth.

These additional treatment choices have their own risks. Weigh the risks and benefits with your eye doctor to see if surgery is right for you.

A pterygium may not cause problems other than redness and eye irritation. If it grows onto your cornea, it may cause vision problems. Treatment can also sometimes cause complications. For example, you might get an eye infection after surgery.

Not all cases are preventable. You can reduce your risk of a pterygium by reducing your sun exposure. Use sunglasses and hats when you are outside. Make sure your sunglasses block both ultraviolet A and ultraviolet B rays.

If your pterygium has started to affect your vision, see your eye doctor as soon as possible. Call right away or seek medical attention for any severe symptoms, such as sudden vision loss.

• A pterygium is a type of noncancer growth on your eye. It is often only a minor problem.
• Many people don't have any symptoms, or you might have symptoms, such as eye irritation, itching, burning, or redness.
• You might have blurred vision if your growth covers a large part of your cornea.
• You might only need treatments, such as eye drops to reduce discomfort.
• Some people need surgery to remove their growth, especially if it is causing major symptoms. But it may grow back after surgery.

Tips to help you get the most from a visit to your doctor:

• Know the reason for your visit and what you want to happen.
• Before your visit, write down questions you want answered.
• Bring someone with you to help you ask questions and remember what your doctor tells you.
• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your doctor gives you.
• Know why a new medicine or treatment is prescribed and how it will help you. Also know what the side effects are.
• Ask if your condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if you do not take the medicine or have the test or procedure.
• If you have a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your doctor if you have questions, especially after office hours and on weekends and holidays.