Cataracts

A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to aging and they are very common in older people. By age 80, more than half of all Americans either have a cataract or have had cataract surgery.

A cataract can occur in either one or both eyes. It cannot spread from one eye to the other.

The lens is a clear part of the eye that helps to focus light, or an image, on the retina. The retina is the light-sensitive tissue at the back of the eye. In a normal eye, light passes through the transparent lens to the retina. Once it reaches the retina, light is changed into nerve signals that are sent to the brain. The lens must be clear for the retina to receive a sharp image. If the lens is cloudy from a cataract, the image you see will be blurred. Blurred vision caused by cataracts can make it more difficult to read, drive a car (especially at night), or see other peoples’ facial expressions.

Most cataracts develop slowly and do not disturb your eyesight in early stages. Over time, a cataract will eventually interfere with your vision. At first, stronger lighting and eyeglasses can help you deal with cataracts. If blurred or difficult vision interferes with your usual activities, you might need cataract surgery. Fortunately, cataract surgery is generally a safe, effective procedure.

Signs and symptoms of cataracts include:

• Clouded, blurred, or dim vision
• Increasing difficulty with vision at night
• Sensitivity to light and glare
• Seeing "halos" around lights
• Frequent changes in eyeglass or contact lens prescription
• Colors seem faded
• Double vision or multiple images in a single eye

At first, the cloudiness in your vision caused by a cataract may affect only a small part of the eye's lens and you may be unaware of any vision loss. As the cataract grows larger, it clouds more of the lens and distorts the light passing through the lens. This may lead to more noticeable signs and symptoms.

Most cataracts develop when aging or injury changes the tissue that makes up your eye's lens. Some cataracts are related to inherited genetic disorders that cause other health problems and increase your risk of cataracts. Cataracts can also be caused by other eye conditions, medical conditions such as diabetes, trauma or past eye surgery. Cataracts may develop in only one eye, but they usually develop in both of your eyes.

The risk of cataract increases as you get older. Other risk factors for cataract include:

• Certain diseases such as diabetes
• Personal behavior such as smoking and alcohol use
• The environment such as prolonged exposure to sunlight

Cataract is detected through a comprehensive eye exam that includes:

• Visual acuity test. This eye chart test measures how well you see at various distances. You may be asked to read a standard eye chart.
• Slit-lamp examination. This type of exam uses a light and magnification to examine the structures at the front of your eye. It uses an intense light to illuminate the cornea, iris, lens, and the spaces surrounding these structures.
• Dilated eye exam. Drops are placed in your eyes to widen, or dilate, the pupils. Your eye care professional uses a special magnifying lens to examine your retina and optic nerve for signs of damage and other eye problems. After the exam, your close-up vision may remain blurred for several hours.
• Tonometry. An instrument measures the pressure inside the eye. Numbing drops may be applied to your eye for this test.

Your eye care professional also may do other tests to learn more about the structure and health of your eye.

Wearing sunglasses and a hat with a brim to block ultraviolet sunlight may help to delay the formation of cataract. If you smoke, stop. Researchers also believe good nutrition can help reduce the risk of age-related cataract. They recommend eating green leafy vegetables, fruit, and other foods with antioxidants.

If you are age 60 or older, you should have a comprehensive dilated eye exam at least once every two years. In addition to cataract, your eye care professional can check for signs of age-related macular degeneration, glaucoma, and other vision disorders. Early treatment for many eye diseases may save your sight.

To deal with symptoms of cataracts:

• Make sure your eyeglasses or contact lenses are the most accurate prescription possible
• Use a magnifying glass to read
• Improve the lighting in your home with more or brighter lamps
• Wear sunglasses or a broad-brimmed hat to reduce glare when you go outside during the day
• Limit your night driving

These self-care measures may help for a while, but as the cataract progresses, your vision may deteriorate further. When vision loss starts to interfere with your everyday activities, you and your doctor may consider cataract surgery.

Surgery is the only curative treatment for cataracts. Most eye doctors suggest considering cataract surgery when your cataracts begin to affect your quality of life or interfere with your ability to perform normal daily activities, such as reading or driving at night. In general, there is no rush to remove cataracts because they usually do not harm the eye.

Delaying surgery will not change the chances of recovering your vision if you later decide to have cataract surgery. Take time to consider the benefits and risks of cataract surgery with your doctor.