| Low vision
aids can help people with partial vision loss function
at higher levels. Low vision aids do not restore sight
but make it easier for people with vision loss to take
advantage of their remaining abilities. These visual
devices fall into three categories: Non-optical aids,
optical aids, and electronic aids.
Non-optical aids
- Lighting - Adequate lighting is the most
important aid to good vision. Use high-intensity,
adjustable lamps to allow light to fall directly on
the items to be viewed and not into the eyes. If
vision is better in one eye than the other, position
the light source over the shoulder of the better
eye. Curtains and window blinds should be adjusted
to allow daylight to fall on your work as well.
- Make sure lighting is adequate, day and
night, in key areas:
- outdoors
- garage
- storage areas
- stairways
- work spaces
- favorite reading places
- Keep flashlights in your car and in a bag
for unexpected situations.
- If your vision is best in the morning,
schedule your reading and detailed work
accordingly;
- If your ability to see in the dark is
diminished or you have increased sensitivity to
glare:
- Use caution when walking near traffic.
- Drive only on well-lit roads.
- Keep your windshield, headlights and
glasses clean.
- Wear anti-glare glasses.
- Consider avoiding driving at night.
- Consider not driving at all.
- Typoscopes - A typoscope is a dark piece
of matte cardboard with an oblong slot cut from the
middle. When placed over text, the typoscope frames
a visible section, eliminating glare from the
surrounding white space. The cardboard is slid
across text to read it. Although sold at low-vision
resource centers, typoscopes are easily hand-made.
- Reading stands - A reading stand raises
reading materials so that low-vision sufferers do
not need to stoop over their work.
Optical Aids
- Magnifiers - Magnifiers come in all
shapes, sizes and strengths. From hand-held pocket
sized to those with tabletop stands, some models
enlarge text up to 15 times. Rectangular shapes are
better for reading, round for spotting items.
Magnifying lenses can be fit over your glasses or on
a headband. Some people find these difficult to use, as
text must be held very close to the lenses. These may be
used in conjunction with hand-held magnifiers.
Whether hand-held, stand-alone, or eyeglass-mounted,
strong magnifiers will distort images unless they have
curved lenses. The stronger the magnifier, the smaller
its field of view.
Illuminated magnifiers are available for use in poor
lighting.
- Telescopes - For spotting street signs or
checking airplane departure time, hand-held or
eyeglass-mounted telescopes can be invaluable tools.
Monacle (fitted for one eye) or binocular (fitted
for both eyes) telescopes may help people with low
vision work at distances greater than arm's length
Electronic Aids
- Closed circuit televisions - Closed
circuit televisions (CCTV) are available to alter
images electronically, improving their contrast,
brightness and magnification.
Reading matter is electronically input by a scanner
or video camera, greatly enlarged, and displayed on a
television screen or computer monitor. Some plug into a
normal television set. With some models, the reader
moves the scanner back and forth over across the text.
Other devices use a full-page document scanner. CCTVs
are stationary units, usually set up on a desk at the
home or in the office.
- Head-mounted displays - Head-mounted
displays are wearable electronic magnification
systems - in essence, portable CCTVs. These capture
images through a video camera, then transmit them at
higher magnification to a head-mounted display unit.
Many units cannot display animated images. Some
users may find head-mounted displays to be heavy or
uncomfortable.
Not all low-vision aids are appropriate with everyone
with partial vision loss. Each person's needs vary.
Several factors influence the successful use of the
various low vision aids, including proper training,
comfort and ease of use. Your eye doctor and low-vision
specialists can help you select suitable devices and
learn how to use them to their full potential. |