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.

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

See an eye doctor if cloudy, blurred, or dim vision, glare, or trouble seeing at night is affecting daily activities. Cataract surgery is safe and very effective when vision loss interferes with your life.