Many people have heard of cataracts, but few know what it is, what causes it, and what they should do if they think they are experiencing the symptoms of cataracts.

A cataract affects the lens of the eye. The lens, which is made mostly of water and protein, is the part of the eye that helps focus light on the retina. The retina turns what the eye sees into visual signals that are sent to the brain. To focus the light on the retina, the lens must remain clear. If the protein arranged on the lens clumps together it can create a cloudy effect. This cloudiness can block some of the light reaching the retina, causing vision problems.

"At age 10, the lens is crystal clear. It becomes more and more cloudy with age. Most people around 60 or 70 years of age begin to have some visual disability. When the cloudiness reaches the point that people notice it as a problem, that's called a cataract," explained Thomas Oetting, M.D., University of Iowa Hospitals and Clinics' Department of Ophthalmology and Visual Sciences.

The most common type of cataract is age-related. Cataracts, however, can also be caused by congenital factors, conditions such as diabetes, environmental factors such as eye trauma, medicines such as prednisone, or poor nutrition.

If you feel that you are experiencing symptoms from a cataract, you should obtain a comprehensive eye exam including a visual acuity test (eye chart to test ability to see at various distances), pupil dilation (to see the lens and retina and check for other problems), and tonometry (a test of the fluid pressure in the eye to check for glaucoma).

If a cataract is detected, the treatment may vary depending on how early it is detected. People with an early cataract, according to Oetting, may need frequent changes in the prescription for their glasses, but with the changes in glasses they are able to see well.

"After awhile, however, the visual dysfunction is enough that patients become willing to accept the slight risk of surgery, which is the only effective treatment," Oetting states.

A cataract needs to be removed surgically when vision loss interferes with everyday activities such as watching TV, reading, or driving. Cataract surgery is a common, fairly simple procedure with only mild discomfort. Less than one percent of patients see worse than before the procedure, while ninety-six percent see normally again. Most people who have cataract surgery can go home the same day.

At this time, it is not known how to protect against cataracts. Oetting reported that recent evidence suggests that good nutrition may play a role in protecting against cataracts. In particular, anti-oxidants may be important. Oetting also stated that evidence suggests that protecting against ultra-violet rays, such as through the use of UV coated sunglasses may be beneficial. The National Eye Institute suggests that if you are age 60 or over, you should have an eye exam at least every two years.

Although the treatment for cataracts has become standard, researchers are working on some exciting new developments. According to Oetting, one of the most exciting research areas is the creation of an artificial lens, as opposed to the clear plastic lens currently used in cataract surgery, that would allow patients to have an eye with zoom capabilities, which is currently not possible with the plastic lens. This research, along with an improved understanding of how to protect against cataracts may help ophthalmologists at UI Hospitals and Clinics care for Iowans' eyes.

For more information on cataracts, contact the UI Department of Ophthalmology and Visual Sciences at (319) 353-7617. You can also obtain information at the department's website at http://webeye.ophth.uiowa.edu/

Back to top