Important facts you should know

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In the News...

High dietary carbohydrate intake linked to cataract formation Recent results from a study of 3,377 men and women, ages 60 to 80, suggest that a diet rich in foods with a high glycemic index is associated with an increased risk of cataracts. The researchers speculated that foods with a higher glycemic index may increase the damage to the lens by exposing the tissue to glucose for longer periods. American Journal of Clinical Nutrition Read more about the glycemic index from the University of Sydney, Linus Pauling Institute, American Heart Association, and the Joslin Diabetes Center

What is a cataract?

A major cause of visual impairment and the leading cause of blindness worldwide, a cataract is a painless, cloudy area in the lens of the eye. It is not a growth or a tumor, but a change in the clarity of the lens. Lying just behind the pupil, the lens allows the eye to focus and helps you see a sharp image. If the lens is cloudy from a cataract, the image you see will be blurred.

Cataracts can occur in either or both eyes at the same time, but they may develop at different rates. Cataracts are not contagious and do not "spread" from one eye to the other.

Causes of Cataracts
  • Aging: Most cataracts are related to aging, usually starting after age 50, but sometimes they can begin at a younger age. Even though a cataract can start to form in your 50's, vision problems may not occur until much later.(4) By age 80, more than half of all Americans either have a cataract or have had cataract surgery.(2)
  • UV radiation: Prolonged exposure to ultraviolet radiation (UV-A and UV-B rays)
  • Smoking and excessive alcohol use
  • Eye injury
  • Eye disease
  • Certain medications such as corticosteroids
  • Medical conditions such as diabetes.
  • Congenital: Some babies are born with cataracts or develop them in childhood, often in both eyes. These cataracts may be so small that they do not affect vision. If they do, the lenses may need to be removed.
  • Radiation cataract. Cataracts can develop after exposure to some types of radiation.
Symptoms of a Cataract (4)

A cataract starts out small and initially has little effect on vision. As it becomes larger and denser, vision becomes more and more impaired. Cataracts may take years to form, or they may worsen rapidly in a few months. Symptoms might include:

  • Blurred vision
  • Cloudy, filmy or fuzzy vision
  • Double vision
  • Poor distance vision
  • Distorted images in either eye
  • Sensitivity to light and glare, especially while driving at night
  • Poor night vision
  • Changes in the way you see colors, or colors seem faded
  • Rapid changes in eyeglass prescriptions
  • Changes in the color of the pupil
  • Cataracts are not painful and do not cause itching, redness, or discharge from the eye.
See your eye doctor if you develop any of the above symptoms.
Prevention of Cataract Formation (3)

Sunglasses and SunProlonged exposure to ultraviolet radiation (UV-A and UV-B rays) can lead to cataract formation.

Sunglasses that block 99 to 100 percent of UV rays are recommended protection against cataract formation. Be careful when purchasing sunglasses that state they "block UV" without saying how much, they need to block 99 to 100 percent of UV rays. (Some labels read "UV protection up to 400nm" -this means 100 percent UV absorption.)

Also keep in mind the following:

  • UV exposure is greater on the snow, sand and pavement, as well as on the water.
  • UV radiation permeates through overcast conditions, such as haze and clouds.
  • UV radiation is highest between 10am and 4pm.
  • UV radiation levels rise in high altitudes (in the mountains) and low latitudes (near the equator).

Eye MDA comprehensive medical examination by an ophthalmologist is recommended at the following intervals:

  • Adults between the ages of 40 to 64: every two to fours years
  • Adults age 65 and older: every one to two years

  • More frequent medical eye exams are recommended for people at higher risk:

    • Children with developmental delay or premature birth
    • Smoker
    • Increased UV Exposure
    • Personal or family history of cataracts or eye disease
    • African-American heritage (African-Americans are at increased risk for glaucoma)
    • Previous serious eye injury
    • Use of certain medications (check with your Eye M.D.)
    • Some diseases that affect the whole body (such as diabetes or HIV infection)

    A cataract may not need to be treated if your vision is only slightly blurry. Often changing the eyeglass prescription may help to improve vision adequately for a while. Cataracts do not go away on their own or with the use of medication. The only way to treat cataracts is to have them removed surgically. When you are no longer able to see well enough to function normally, cataract surgery should be considered. Years ago, surgeons advised patients to let the cataract "ripen" or grow to totally obscure vision before they would remove the cataract. Now, however, with advances in surgical technology, surgeons no longer recommend waiting to remove a cataract, because waiting could make the procedure more difficult to perform.

    In cataract surgery, the cloudy lens is removed from the eye through a surgical incision. In most cases, the natural lens is replaced with a clear, plastic lens. Cataract surgery is usually successful in restoring vision and is one of the most common surgeries performed in the United States. Today's cataract removal procedures are safer and more successful than operations that were used in the past with the current success rate about 98%.(5)

    Surgery is performed by an ophthalmologist and is usually done on an outpatient basis. Following surgery, you will have a short stay in the outpatient recovery area, then be ready to go home that same day, with someone else driving and staying with you for the rest of that evening. Recovering from a cataract operation is usually simple, but you will be asked to follow some important instructions, such as not lifting heavy objects or bending from the waist.

    Video tutorial
    Cataracts from Medline Plus. This is an excellent videotutorial from the National Institute of Health and National Library of Medicine

    (1) Cataracts from Merck Source
    (2) Cataracts: What you should know from the National Eye Institute, National Institute of Health
    (3) Sunglasses from the American Academy of Ophthalmology
    (4) Age-related cataracts from the American Academy of Ophthalmology
    (5) Cataracts patient page from the Journal of the American Medical Association
    (6) American Society of Cataract and Refractive Surgery
    (7) Cataract Surgery in Adults from the American College of Surgeons

    Written by N Thompson, ARNP, MSN and reviewed by M Thompson, MD, Internal Medicine, June 2006

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