Cataract

What is a cataract?

A cataract is a cloudy area in the lens of the eye. The lens helps focus light on the retina at the back of the eye. It is located inside the eye behind the iris (the colored part of the eye). As a cataract worsens over time, the cloudiness worsens and causes vision problems.

How does it occur?

Most cataracts occur naturally as people get older. What causes cataracts is not known, but many factors may contribute to their formation, such as:

• eye injury
• diabetes or other diseases
• exposure to radiation, especially X-rays
• long-term use of steroid medication
• exposure to toxic substances
• an inflammatory disorder of the eye (iritis)
• prolonged exposure to sunlight
• aging.

A child may be born with cataracts or develop them at an early age. These cataracts, called congenital cataracts, may be caused by a genetic disorder (such as Down syndrome) or by a condition the mother had during pregnancy (such as German measles). They also may be inherited.

Cataracts don't spread from one eye to the other, but many people have cataracts in both eyes.

What are the symptoms?

The symptoms of a cataract include:

• blurred vision
• a need for frequent changes in your eyeglasses or contacts
• trouble driving at night
• sensitivity to bright light
• change in color vision (yellow, orange, and red appear brighter and blue appears dull).

Cataracts do not cause complete blindness. However, it is possible to lose enough vision to be declared legally blind.

How is it diagnosed?

The symptoms of a cataract develop slowly and are painless. The condition may go unnoticed and undiagnosed for a long time. It is often first diagnosed during a routine eye exam.

An eye doctor will thoroughly examine your eyes. He or she will evaluate your symptoms and determine the best course of treatment.

How is it treated?

If a cataract is not interfering with your lifestyle or work, your doctor may suggest changing your glasses or using brighter lights to help you read.

If the cataract is seriously affecting your vision and cannot be helped with glasses or contact lenses, a surgeon may need to remove the lens. This type of surgery is called cataract extraction surgery. The surgeon may first use sound waves (ultrasound) to break up the lens so the pieces can then be removed through a narrow hollow suction tube. This part of the procedure is called phacoemulsification. In some cases, the lens is removed in one piece through a larger incision (nuclear expression). After the lens is removed your surgeon may put a new plastic lens in your eye (intraocular lens implantation). If you do not have a new lens put in, you will need to wear contact lenses or cataract glasses.

Lasers are not used to remove cataracts. However, they may be used to open a cloudy membrane that may develop after cataract surgery.

How long will the effects last?

Decreased vision from cataracts is reversible and will last until it is corrected with glasses, contact lenses, or surgery. Surgery to remove cataracts is more than 90% successful in restoring vision. Ask your doctor about his or her success rate.

How can I take care of myself?

• Be sure to follow your doctor's instructions.
• Call your eye doctor if your vision gets worse.
• Be careful when you drive at night. A cataract can make lights such as oncoming headlights seem very bright, causing a glare that makes it hard to see.

What can be done to help prevent cataracts?

You may reduce the risk of damaging your eyes and in turn reduce the risk of developing cataracts by wearing goggles or safety glasses at work or during activities where your eyes could be injured. Wearing glasses with a UV coating that protects your eyes from sunlight might prevent or delay some types of cataracts, but this is not proven.

If you are a woman and plan to have a baby, make sure you have had a German measles (rubella) shot at least 1 month before you try to become pregnant. If you have German measles while you are pregnant, your baby's eyes should be checked by an eye care professional soon after birth. A baby can develop cataracts if you had German measles or other kinds of infections while you were pregnant.