There are an estimated
10 million blind and visually impaired people in the United States,
1.3 million of which are considered legally blind (American Foundation
for the Blind, 2006a). Of this number, approximately 109,000 people
use long canes for assistance, while about 7,000 individuals use
service dogs (American Foundation for the Blind, 2006a).
Vision impairments
result from conditions that range from the presence of some usable
vision, low vision, to the absence of any vision, total blindness.
Low vision is a term that describes a person with a vision impairment
that cannot be improved by correction but has some usable vision
remaining. Legal blindness is defined as 20/200 or less in the
better eye with the best possible correction. Errors of refraction,
diseases of the eye, and other vision-related conditions are usually
the cause of vision loss. Each of these categories includes more
specific disorders, which are described below (American Foundation
for the Blind, 2006b).
Common Errors of Refraction
Myopia (Nearsightedness):
Close objects look clear while distant objects appear blurred.
Hyperopia (Farsightedness):
The ability to see objects clearly at a distance while close objects
appear blurry.
Astigmatism: Due to
the irregular curvature of the cornea, vision is blurry for both
near and far objects.
Presbyopia: The eye
lens becomes less elastic (associated with aging) and produces
blurred vision when focusing on near objects.
Common Diseases of
the Eye
Cataracts: Clouding
of the eye's lens that causes loss of vision.
Glaucoma: Pressure
inside the eye is elevated and can cause damage to the optic nerve,
which results in damage to peripheral vision.
Macular Degeneration:
There is a disturbance of blood vessels in the eye resulting in
progressive loss of central vision.
Retinitis Pigmentosa:
There is a degeneration of pigment in the eye that is needed to
absorb light and create visual images, leading to "tunnel
vision" and night blindness.
Retinopathy (due to
Diabetes): Retinopathy typically affects the blood circulation
of the retina, which causes blotchy vision.
Other Vision Related
Conditions
Night Blindness: Night
blindness results from pigmentary degeneration of the retina,
which leads to difficulty seeing in low light.
Color Vision Deficiency:
A color vision deficiency occurs when cone cells of the retina,
which provide daylight and color vision, are affected and there
is difficulty distinguishing among colors. Typically this only
involves certain hues, for example a red-green deficiency; total
color blindness (achromatic vision) is rare.
Lack of Depth Perception:
A lack of depth perception is often caused by the loss of sight
in one eye, resulting in difficulty with foreground/background
discrimination.
Floaters: Floaters
are small specks or clouds moving in the field of vision.
American Foundation
for the Blind. (2006a). Blindness statistics. Retrieved January
4, 2007, from http://www.afb.org/Section.asp?SectionID=15
American Foundation
for the Blind. (2006b). Glossary of eye conditions. Retrieved
January 4, 2007, from http://www.afb.org/Section.asp?DocumentID=2139
Accommodations are
evaluated on a case-by-case basis. We have compiled a non-inclusive
list of limitations that result in common accommodation situations.
In addition, you can find more information at JAN's A to Z Web
page at: http://www.jan.wvu.edu/media/atoz.htm.
Depending on the individual's
limitations and job functions, additional questions may need to
be asked to determine what accommodations can be effective. For
example:
No vision considerations:
Does the individual
read Braille?
Does the individual
use a cane, navigational aid, or animal to assist with mobility?
Low vision considerations:
Is the individual's
condition progressive or stable?
Does the individual benefit from magnification?
Does the individual
use corrective lenses or assistive devices?
Does the individual
use a cane, navigational aid, or animal to assist with mobility?
Color vision deficiency
considerations:
What colors does the
individual have difficulty distinguishing?
Would the individual
benefit from special red contact lens worn on one eye or prescription
glasses?
Do the individual's
job functions lend themselves to the use of talking products that
scan a color and announce a description of the color?
Please
select the limitation that corresponds with the individual needing
an accommodation below.
Individual
has low vision.
Individual
has no vision. Note: Individuals with low vision
may find the this information helpful also.
Questions
to Consider
Accommodation
Examples
Organizations