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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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