Cataracts - Topic Overview

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Wednesday, 28 November 2007

A cataract is a clouding of the lens of the eye that can impair vision. More than half of all Americans age 65 and older have cataracts in their eyes.

What Causes Cataracts?

The eye functions much like a camera. Light rays enter through the front of the eye, passing through the cornea, the pupil, and the aqueous humor -- transparent fluid in the front of the eye -- onto the lens. The lens then bends light rays to focus objects onto the retina in the back of the eye. From there, the retina, the optic nerve, and the brain process the images and form vision.

Cataracts occur when there is a buildup of protein in the lens that makes it cloudy. This prevents light from passing through a normally clear lens, causing some loss of vision. No one knows what causes the buildup of protein responsible for clouding the lens. The cataract is a lens that has become clouded.

Types of cataracts include:

Age-related cataracts. As the name suggests, this type of cataract develops as a result of aging.
Congenital cataracts. Babies are sometimes born with cataracts as a result of an infection they had before they were born, or they may develop during childhood.
Secondary cataracts. These may develop as a result of other diseases, like diabetes, or long-term exposure to toxic substances, certain medications (such as corticosteroids or diuretics), ultraviolet light, and radiation.
Traumatic cataracts. These can form after injury to the eye.

Other factors that can increase a person's risk of developing cataracts include cigarette smoke, air pollution, and heavy alcohol consumption

Cataracts Eyes

What Are the Symptoms of Cataracts?

Cataracts often form slowly and cause few symptoms. When symptoms are present, they can include:

Vision that is cloudy, blurry, foggy or filmy.
Sudden nearsightedness.
Changes in the way you see color, especially yellow.
Problems driving at night because oncoming headlights are distracting.
Problems with glare.
Double vision.
Sudden temporary improvement in close-up vision.

How Are Cataracts Diagnosed?

A series of tests can be performed by your eye doctor. An eye exam will be given to test how well you can see (remember to bring your glasses or wear your contacts to the appointment). Your doctor will also dilate your pupil in order to examine the condition of the lens and other parts of the eye.

How Are Cataracts Treated?

The eye exam will help the doctor determine how the cataract has affected your vision. If the vision is acceptable, eyeglasses, including bifocals and contacts, may be prescribed, eliminating the need for surgery at that time.

If you suffer from vision loss that impairs your daily life, you may be a candidate for cataract surgery, which involves removing the clouded lens and replacing it with a clear, plastic one.

Cataract surgery is usually conducted on an outpatient basis and is usually successful in restoring vision. In fact, it is the most frequently performed surgery in the U.S., with more than 1.5 million cataract surgeries done each year. Better than nine out of 10 people who have cataract surgery have improvement in vision.

Talk to your doctor to see which treatment is right for you.

Can Cataracts Be Prevented?

Because the exact cause of cataracts is uncertain, there is no proven method of preventing them. Because they are so common in older adults, however, it's important to have your eyes examined on a regular basis. According to the American Academy of Ophthalmology, people aged 40 to 64 should have a comprehensive eye examination every two to four years; people 65 and older should have a comprehensive eye examination every one to two years.

People with a history of eye problems or other medical conditions that increase the risk of eye disease --such as diabetes-- should have eye exams more frequently (once a year or as recommended by your doctor).

Reviewed by the doctors at The Cleveland Clinic Cole Eye Institute.

VitaDocs Medical Reference provided in collaboration with the Cleveland Clinic