What is a cataract?
A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to aging. Cataracts 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 or both eyes. It cannot spread from one eye to the other.
What is the lens?
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.
CAUSES AND RISK FACTORS
What causes cataracts?
The lens lies behind the iris and the pupil (see diagram). It works much like a camera lens. The lens is made of mostly water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it. But as we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract. Researchers suspect that there are several causes of cataract, such as smoking and diabetes. Or, it may be that the protein in the lens just changes from the wear and tear it takes over the years.
When are you most likely to have a cataract?
The term "age-related" is a little misleading. You don't have to be a senior citizen to get this type of cataract. In fact, people can have an age-related cataract in their 40s and 50s. But during middle age, most cataracts are small and do not affect vision. It is after age 60 that most cataracts steal vision.
Who is at risk for cataract ?
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.
SYMPTOMS AND DETECTION
What are the symptoms of a cataract ?
The most common symptoms of a cataract are: Cloudy or blurry vision. Colors seem faded. Glare. Headlights, lamps, or sunlight may appear too bright. A halo may appear around lights. Poor night vision. Double vision or multiple images in one eye. (This symptom may clear as the cataract gets larger.) Frequent prescription changes in your eyeglasses or contact lenses. These symptoms also can be a sign of other eye problems. If you have any of these symptoms, check with your eye care professional.
How is a cataract detected ?
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. 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.
How is a cataract treated ?
The symptoms of early cataract may be improved with new eyeglasses, brighter lighting, anti-glare sunglasses, or magnifying lenses. If these measures do not help, surgery is the only effective treatment. Surgery involves removing the cloudy lens and replacing it with an artificial lens. A cataract needs to be removed only when vision loss interferes with your everyday activities, such as driving, reading, or watching TV. Once you understand the benefits and risks of surgery, you can make an informed decision about whether cataract surgery is right for you. In most cases, delaying cataract surgery will not cause long-term damage to your eye or make the surgery more difficult. You do not have to rush into surgery. If your eye care professional finds a cataract, you may not need cataract surgery for several years. In fact, you might never need cataract surgery. By having your vision tested regularly, you and your eye care professional can discuss if and when you might need treatment. If you have other eye conditions in addition to cataract, talk with your doctor. Learn about the risks, benefits, alternatives, and expected results of cataract surgery.