What is a Cataract?
A cataract is a cloudy area in the lens of the eye. A normal lens is clear. It lets light pass to the back of the eye. A cataract blocks some of the light. As a cataract develops, it becomes harder for a person to see.
Normal Lens Cataract
Cataracts are a normal part of aging. About half of Americans ages 65 to 74 have cataracts. About 70 percent of those age 75 and over have this condition.
Most people with cataracts have a cataract in both eyes. However, one eye may be worse than the other because each cataract develops at a different rate.
Some people with cataract don't even know it. Their cataract may be small, or the changes in their vision may not bother them very much. Other people who have cataracts cannot see well enough to do the things they need or want to do.
What Are the Symptoms of a Cataract?
Here are some symptoms of a cataract:
- Cloudy, fuzzy, foggy, or filmy vision.
- Changes in the way you see colors.
- Problems driving at night because headlights seem too bright.
- Problems with glare from lamps or the sun.
- Frequent changes in your eyeglass prescription.
- Double vision.
- Better near vision for a while only in farsighted people.
These symptoms also can be signs of other eye problems, so if you are experiencing any of them, call your ophthalmologist to make an appointment for an eye exam.
How is a Cataract Diagnosed?
A regular eye exam is all that is needed to find a cataract. Your ophthalmologist will ask you to read a letter chart to see how sharp your sight is. You probably will get eye drops to enlarge your pupils (the round black centers of your eyes). This helps the doctor to see the inside of your eyes. The doctor will use a bright light to see whether your lenses are clear and to check for other problems in the back of your eyes.
Other eye tests may also be used occasionally to show how poorly you see with a cataract or how well you might see after surgery, including:
- Glare test.
- Contrast sensitivity test.
- Potential vision test.
Not all people need all of these tests, so you may not have all of these performed.
How is a Cataract Treated?
If your cataracts are not very developed, a change in your glasses, stronger bifocals, or the use of magnifying lenses may help improve your vision and be treatment enough. If your cataracts are far enough along, they can be surgically treated by removing the lens and replacing it with an artificial lens.
Just because you have a cataract does not mean it must be removed immediately. In many cases, a person may have cataracts developing for five, ten, or more years before surgery becomes necessary. Cataract surgery can almost always be put off until you are unhappy with the way you see.
Your ophthalmologist will tell you whether you are one of a small number of people who must have surgery. For example, your doctor may need to see or treat an eye problem that is behind the cataract. Or surgery may be required because a cataract is so large it could cause blindness.