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What is low vision? If
ordinary eyeglasses, contact lenses or intraocular lens implants
don't give you clear vision, you are said to have low
vision. You should not confuse this condition with
blindness. People with low vision still have useful vision
that can often be improved with visual devices. Whether
your visual impairment is mild or severe, low vision generally
means that your vision does not meet your needs. Using
visual devices to improve your vision usually begins after your
ophthalmologist has completed medical or surgical treatment or
determined that such treatments will not improve your vision. What
causes low vision? Though
most often experienced by the elderly, people of all ages may be
affected. Low vision can occur from birth defects, inherited
diseases, injuries, diabetes, glaucoma, cataract and aging.
The most common cause is macular degeneration, a disease of the
retina, the inner layer of the eye that senses light and allows
you to see. Macular degeneration causes damage to central
vision. It does not cause total blindness, because side
(peripheral) vision is not affected. Are
there different types of low vision? Yes.
Although reduced central or reading vision is most common, low
vision may also result from decreased side (peripheral) vision, or
a loss of color vision. Or, your eye might lose the ability
to adjust to light, contrast or glare. Different
types of low vision may require different kinds of
assistance. For example, people born with low vision have
different needs from those who develop low vision later in life. What
is a low vision device? A low
vision device is an apparatus that improves vision. There is
no one device that restores normal vision in all circumstances, so
you may need different devices for different purposes. If
possible, try a device before you buy it to see if it is useful
for you. There are two types
of low vision devices: optical and non-optical. Optical
low vision devices Optical
low vision devices use lenses or combinations of lenses to provide
magnification. They should not be confused with standard
eyeglasses. There are five main kinds of optical devices:
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Magnifying spectacles
are stronger than ordinary glasses. When you use them,
you need to hold your reading material very close; otherwise
the print is out of focus. This may feel awkward at
first, but you will become used to it. They are designed
for close work, so magnifying spectacles leave both hands free
to hold reading material.
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Hand magnifiers are
familiar to most people. With these, you can hold
reading material at a normal distance. You can buy hand
magnifiers in department or drug stores.
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Stand magnifiers rest on
the reading material. Some have a self contained light
source.
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Telescopes are used for
distance magnification. They may be hand held for
viewing distant objects, or mounted in spectacles.
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Closed-circuit television
produces an enlarged image on a television screen. With
adjustable magnification and contrast, a closed-circuit
television is often easier to use than other devices.
Non-optical low vision
devices
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Large-print books, newspapers
and magazines
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Check-writing guides
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Large playing cards
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Enlarged telephone dials
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High-contrast watch faces
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Machines that talk (timers,
clocks, computers)
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Machines that scan print and
read aloud
The simplest non-optical technique
is getting closer to what you want to see. Holding reading
material very close to your eyes or sitting as close as one foot
from the television screen will not cause eye damage, contrary to
popular belief.
Is lighting important for people
with low vision?
Correct lighting is as important as
a low vision device. With no eye disorder, a 60-year-old
person may need twice the illumination he or she needed at 20 to
comfortably perform the same task. Some lighting tips:
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Place the light source close to
your reading material for greatest visability. High
intensity lights with adjustable arms work well for this
purpose
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Visors and hat brims block
annoying overhead light
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Absorptive lenses are useful in
controlling glare
What services are available for low
vision patients?
A complete eye examination by an
ophthalmologist is essential. An ophthalmologist is
essential. An ophthalmologist is a medical doctor (MD or DO)
educated, trained and licensed to provide total eye care,
including diagnosing causes of low vision and prescribing low
vision devices.
Once the cause of your low vision
is determined, your ophthalmologist may suggest low vision devices
or may refer you to other low vision specialists or agencies for
help.
Governmental and private agencies
provide social services for people with low vision. These
include talking books, independent home-living instruction and, in
some cases, orientation and mobility training.
For additional information
contact:
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You local state commission for
the blind and visually impaired
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American Foundation for the
Blind, 11 Penn Plaza, Suite 300, New York, NY 10001,
(800)232-5463
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National Association for
Visually Handicapped, 22 West 21st Street, New York, NY 10010,
(212)889-3141
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National Library Service for
the Blind and Physically Handicapped, Library of Congress,
Washington, D.C. 20542, (800)424-8567
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The Lighthouse National Center
for Vision and Aging, 111 East 59th Street, New York, NY
10022, (800)334-5497
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