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.
Age-related cataracts develop in two ways:
1. Clumps of protein reduce the sharpness of the image reaching the
retina.
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The lens consists mostly of water and protein. When the protein clumps up, it
clouds the lens and reduces the light that reaches the retina. The clouding may
become severe enough to cause blurred vision. Most age-related cataracts develop
from protein clumpings.
When a cataract is small, the cloudiness affects only a small part of the
lens. You may not notice any changes in your vision. Cataracts tend to “grow”
slowly, so vision gets worse gradually. Over time, the cloudy area in the lens
may get larger, and the cataract may increase in size. Seeing may become more
difficult. Your vision may get duller or blurrier.
2. The clear lens slowly changes to a yellowish/brownish color, adding a
brownish tint to vision.
As the clear lens slowly colors with age, your vision gradually may acquire a
brownish shade. At first, the amount of tinting may be small and may not cause a
vision problem. Over time, increased tinting may make it more difficult to read
and perform other routine activities. This gradual change in the amount of
tinting does not affect the sharpness of the image transmitted to the
retina.
If you have advanced lens discoloration, you may not be able to identify
blues and purples. You may be wearing what you believe to be a pair of black
socks, only to find out from friends that you are wearing purple socks.
The risk of cataract increases as you get older. Other risk factors for
cataract include:
- Certain diseases (for example, diabetes).
- Personal behavior (smoking, alcohol use).
- The environment (prolonged exposure to ultraviolet sunlight).
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.
Yes. Although most cataracts are related to aging, there are other types of
cataract:
- Secondary cataract. Cataracts can form after surgery for other eye
problems, such as glaucoma. Cataracts also can develop in people who have other
health problems, such as diabetes. Cataracts are sometimes linked to steroid
use.
- Traumatic cataract. Cataracts can develop after an eye injury,
sometimes years later.
- Congenital cataract. 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.
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.
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. You and your
eye care professional can make this decision together. 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.
Sometimes a cataract should be removed even if it does not cause problems
with your vision. For example, a cataract should be removed if it prevents
examination or treatment of another eye problem, such as age-related macular
degeneration or diabetic retinopathy.
If you choose surgery, your eye care professional may refer you to a
specialist to remove the cataract.
If you have cataracts in both eyes that require surgery, the surgery will be
performed on each eye at separate times, usually four to eight weeks apart.
Cataract removal is one of the most common operations performed in the United
States. It also is one of the safest and most effective types of surgery. In
about 90 percent of cases, people who have cataract surgery have better vision
afterward.
There are two types of cataract surgery. Your doctor can explain the
differences and help determine which is better for you:
- Phacoemulsification, or phaco. A small incision is made on the
side of the cornea, the clear, dome-shaped surface that covers the front of the
eye. Your doctor inserts a tiny probe into the eye. This device emits ultrasound
waves that soften and break up the lens so that it can be removed by suction.
Most cataract surgery today is done by phacoemulsification, also called “small
incision cataract surgery.”
- Extracapsular surgery. Your doctor makes a longer incision on the
side of the cornea and removes the cloudy core of the lens in one piece. The
rest of the lens is removed by suction.
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