Why Cataracts Develop & How to Lower Your Risk
The eye’s clear lens plays an important role in
the remarkable process of sight. It focuses light—just like a camera’s
lens—on the light-sensitive tissue at the back of the eye. The lens
adjusts its focus, changing shape so that we can see things clearly both
up close and far away. Light is then transformed into nerve signals that
travel to the brain, which interprets the light as an image, creating our
experience of sight.
The lens is made up of protein and water. As we
age, some of the protein may clump together and begin to cloud a small
area of the lens. This is a cataract.
The American Optometric
Association has declared August Cataract Awareness Month to spotlight this
most common age-related eye disease, which affects more than 17 percent of
Americans over age 40. By age 80 more than half of us either have a
cataract or have had cataract surgery.
Cataracts are one of the
leading causes of vision loss among American seniors. Worldwide, they are
the number one cause of vision loss.
Seeing the World Through a Cataract
A cataract forms slowly and
painlessly. In the beginning, it affects only a small area of the eye, and
vision changes might not be noticeable. As it gradually progresses, the
cataract grows larger. It clouds the lens and prevents it from focusing
A cataract may change your vision in one of two ways:
- Eyesight becomes blurred, as though you were looking through a cloudy
piece of glass or at an impressionist painting. Lights may seem too bright.
Halos may appear around them.
- The lens takes on a
yellowish-brownish color. This tinting does not affect the sharpness of the
image, but makes colors seem faded. Night vision may be poor.
If you have any of the above symptoms, make an appointment to see your
eye care provider for a comprehensive exam.
Vigorous exercise and
healthy eating may help prevent vision loss.
Are You at Risk for Cataracts?
Your chances of developing a cataract
increase as you get older. Other risk factors include being female, a family
history of cataracts, eye inflammation or injury, surgery for another eye
problem, hypertension, diabetes, smoking, long-term use of steroids, heavy
alcohol use and prolonged exposure to the sun’s ultraviolet light.
Many risk factors are out of our control, but not all. New research
suggests that vigorous exercise and healthy eating may help prevent vision
loss from cataracts and other eye diseases. A U.S. Dept. of Energy study
tracked 41,000 male runners for more than seven years. Men who ran more than
5.7 miles per day had a 35 percent lower risk of developing cataracts than
those who ran less than 1.4 miles per day.
A separate study of over
1,800 women ages 50 to 79 determined that those who followed nationally
recommended dietary guidelines most closely had a 37 percent lower risk of
There is a link between depletion of the Earth’s ozone
layer and increased incidence of cataracts.
Focus on Eye-Healthy Foods
The American Optometric Association recommends the
following foods, which contain key nutrients for eye heath:
and zeaxanthin: Brightly colored fruits and vegetables such as broccoli,
spinach, kale, corn, green beans, peas, oranges and tangerines.
- Essential fatty acids: Fatty fish such as tuna, salmon or herring,
whole-grain foods, chicken and eggs.
- Vitamin C: Fruits and
vegetables, including oranges, grapefruit, strawberries, papaya, green
peppers and tomatoes.
- Vitamin E: Vegetable oils, almonds, pecans,
sweet potatoes, sunflower seeds.
- Zinc: Extra-lean red meat,
poultry, liver, shellfish, milk, baked beans, whole grains
It’s long been known that ultraviolet (UV) radiation from the sun can harm
eyes. Now Prevent Blindness America (PBA) is raising awareness about the link
between depletion of the Earth’s ozone layer—which blocks some UV light from
penetrating the Earth’s atmosphere—and cataracts that are caused by prolonged
exposure to UV light.
This makes it more important than ever to
protect your eyes from the sun. PBA suggests wearing a wide-brimmed hat and
sunglasses that block 99 to 100% of both UV-A and UV-B rays whenever you spend
Surgery: The Only Treatment
The only treatment for a cataract is surgery to
remove it. Cataract surgery is one of the safest and most common operations in
the U.S., and boasts a high success rate. Fully 90 percent of patients
experience better vision afterwards.
During surgery, the doctor inserts
a tiny probe through a small incision on the side of the cornea. The probe
emits ultrasound waves to soften and break up the lens so that it can be
removed easily by suction. Or the doctor may make a longer incision to remove
the cloudy core of the lens in one piece. The rest is suctioned out.
During surgery, the natural lens is replaced with an artificial intraocular
lens (IOL). The new IOL can be folded and slipped or rolled into place
through the small incision, which is self- sealing. The IOL cannot be felt
or seen, needs no care, and becomes a permanent part of the eye.
21st Century Science at Work
learned a lot about cataracts in the past few years. In 2009 researchers
at the University of Wisconsin—Madison discovered a cataract-related
gene. Scientists believe that the normal gene keeps the lens clear while
the mutant variations create proteins that cloud the lens. They hope this
discovery will lead to new treatments.
In 2008 scientists created a
new diagnostic tool that can reveal the earliest damage to the lens before a
cataract develops. People may then be able to reduce their cataract risk by
making simple lifestyle changes: shielding their eyes from the sun, eating
right, exercising, quitting smoking, cutting back on alcohol and
controlling high blood pressure and diabetes.
Cataracts may be
prevalent among older Americans, but when you take control of the many
lifestyle-related risk factors, chances are good that you can maintain eye
health well into your senior years.
American Optometric Association, National Eye
Institute, All About Vision, Vision Monday, Live Science, U.S. News &
World Report, Insciences Organization, Lawrence Berkeley National