What Is It?
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A cataract is a cloudy or opaque area in the normally
transparent lens of the eye, which prevents light rays from passing through
the lens and focusing on the retina. Early lens changes or opacities may not
disturb vision. But as the lens continues to change, several specific symptoms
including blurred vision; sensitivity to light and glare; increased
near-sightedness; or distorted images in either eye, may develop. |
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| Causes
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No one knows exactly why the eyes lens changes as we age.
Researchers, looking for preventive measures, are gradually identifying factors
that may initiate or facilitate the development of cataracts.
Recent studies show people living in high altitudes or those who spend a lot
of time in the sun develop cataracts earlier than others. Ophthalmologists now
recommend wearing sunglasses and a wide-brimmed hat to lessen the eyes' exposure
to UV light.
Other studies suggest people with diabetes are at risk for developing a cataract,
as are users of steroids, diuretics, and major tranquilizers. But more studies are
needed to differentiate the effect of the disease from the effect of the drugs
themselves. |
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| Types of Cataracts
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There are three types of cataracts. Each is described by
its location on the lens. The most common type of cataract and the one
associated with aging is called a nuclear cataract.
- Nuclear cataract occurs in the center of
the lens. Common symptoms include blurring or dimming of your vision, glare
and visual distortion. A nuclear cataract can induce myopia, or near-sightedness,
a temporary improvement in your reading vision sometimes referred to as
"second sight." Unfortunately "second sight" disappears as the cataract
gets worse.
- Cortical cataract begins as wedge-shaped spokes in the cortex of the lens.
The spokes extend from the outside of the lens to the center. When the spokes
reach the center, they interfere with the transmission of light and cause glare
and loss of contrast. Many people with diabetes develop this type of cataract.
Although a cortical cataract usually develops slowly, it may impair both distance
and near vision so significantly that surgery may be suggested at a relatively
early stage.
- Subcapsular cataract develops slowly and starts as a small opacity under the
capsule, usually at the back of the lens. Significant visual symptoms may not
appear until the cataract is well developed. Typical symptoms are glare and blur.
A subcapsular cataract is often found in people with diabetes or high myopia,
adults with retinitis pigmentosa, and in people taking steroids.
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| Symptoms
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If you have a cataract, you may experience these symptoms:
- Painless blurring or dimming of your vision.
- Sensitivity to light and glare, especially in bright sunlight or while driving at night.
- Increased near-sightedness, requiring frequent changes in your eyeglass prescription.
- Distortion or ghost images in either eye.
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| Treatement
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The cataract may need no treatment at all if the vision is
only a little blurry. A change in your eyeglass prescription may improve vision
for a while. There are no medications, eye drops, exercises or glasses that will
cause cataracts to disappear once they have formed. When you are not able to see
well enough to do the things you like to do, cataract surgery should be considered.
Surgery is the only way to remove a cataract.
Cataracts cannot be removed with a laser, only through a surgical incision. In
cataract surgery, the cloudy lens is removed from the eye. In most cases, replacing
it with a permanent intraocular lens implant restores the focusing power of the
natural lens. |
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