Visually Impaired
By: Shawn Podell
Spring 2010
What is it?
Total blindness is the inability to tell light from dark, or the
total inability to see.
Visual impairment or low vision is a severe reduction in
vision that can't be corrected with standard glasses or contact
lenses and reduces a person's ability to function at certain or
all tasks.
Legal blindness (which is actually a severe visual impairment)
refers to a best-corrected central vision of 20/200.
Example: side vision that is so reduced that it appears as if
the person is looking through a tunnel).
What is it Continued?
The World Health Organization (WHO) defines impaired vision
in five categories:
Low vision 1 is a best corrected visual acuity of 20/70.
Low vision 2 starts at 20/200.
Blindness 3 is below 20/400.
Blindness 4 is worse than 5/300.
Blindness 5 is no light perception at all.
What is it Continued?
Color blindness is the reduced ability to perceive
certain colors, usually red and green. It is a
hereditary defect and affects very few tasks.
Contrast sensitivity describes the ability to
distinguish one object from another. A person with
reduced contrast sensitivity may have problems
seeing things in the fog because of the decrease in
contrast between the object and the fog.
Facts
According to the WHO there are over forty million people
worldwide whose vision is category 3 or worse, 80% of whom
live in developing countries.
Half of the blind population in the United States is over 65
years of age.
Trachoma is responsible for six to nine million cases of
blindness around the world, of the third of a billion who have
the disease.
The American Foundation for the Blind estimates that 10
million people in the United States are visually impaired.
Facts
Twenty-one percent of people age 65 and over report some
form of vision impairment. This represents 7.3 million people.
In 2000, 1.7 million of 10.5 million California residents age 45 or
older, and 755,000 of 3.5 million who are 65 or older, had a self-
reported vision problem.
There are 15 million blind and visually impaired people in the
United States, according to Research to Prevent Blindness.
In the United States blindness follows only cancer and AIDS as
the biggest health fear by the public.
Only one in three visually impaired people of employment age
is in the workforce.
Facts
Who Typically Becomes Blind?
Vision problems affect one in 20 (nearly 5 million) preschool-
age children, ages 3-5, and 25 percent (12.1 million) of school-
age children, ages 6-17. Every 7 minutes a person in the
United States loses their sight, often as part of the aging
process. Seventy percent of severely visually impaired
persons are age 65 or older. Fifty percent of that group are
legally blind.
Because women generally live longer than men, visual
impairment statistics are overrepresented in favor of women.
Facts
Legal blindness does not necessarily mean total blindness; 90
percent of people who are legally blind have some remaining
vision.
Just 2 percent of legally blind people use a guide dog; 35
percent use a white cane.
Approximately 90 percent of blind jobholders in the United
States are braille literate.
Thirty-three states have enacted bills promoting braille
instruction within K-12 school systems.
Leading Causes &
Symptoms
More Causes & Symptoms
Exposure of a pregnant woman to certain diseases (ex: rubella or toxoplasmosis can cause
congenital eye problems.
Injuries to the eyes can result in blindness & very little blindness is due to disease in the brain
or the optic nerves.
Multiple sclerosis and similar nervous system diseases, brain tumors, diseases of the eye
sockets, and head injuries are rare causes of blindness.
Vitamin A deficiency is a widespread cause of corneal degeneration in children in developing
nations. As many as five million children develop xerophthalmia from this deficiency each
year. Five percent end up blind.
Causes from Infections
Most infectious eye diseases have been eliminated in the industrialized nations by sanitation,
medication, and public health measures. Viral infections are the main exception to this
statement. Some infections that may lead to visual impairment include:
Herpes simplex keratitis - A viral infection of the cornea. Repeated occurrences may lead to
corneal scarring.
Trachoma - is caused by an incomplete bacterium, Chlamydia trachomatis, that is easily treated
with standard antibiotics. It is transmitted directly from eye to eye, mostly by flies. The chlamydia
gradually destroy the cornea.
Leprosy (Hansen's disease) - This is another bacterial disease that has a high affinity for the
eyes. It, too, can be effectively treated with medicines.
River blindness - much of the tropics of the Eastern Hemisphere are infested with Onchocerca
volvulus,a worm that causes "river blindness." This worm is transmitted by fly bites and can be treated
with a drug called ivermectin. Nevertheless, twenty-eight million people have the disease, and 40% of
them are blind from it.
Diagnosis
A low vision exam is slightly different from a general exam.
While a case history, visual status, and eye health evaluation
are common to both exams, some things do differ. Eye charts
other than a Snellen eye chart will be used. Testing distance
will vary. A trial frame worn by the patient is usually used
instead of the instrument containing the lenses the patient sits
behind (phoropter). Because the low vision exam is slightly
more goal oriented than a general exam, for example, what
specifically is the patient having trouble with (reading, seeing
street signs, etc.) different optical and nonoptical aids will
generally be tried. Eye health is the last thing to be checked so
that the lights necessary to examine the eyes won't interfere
with the rest of the testing.
Treatment
There are many options for patients with visual impairment. There are optical and nonoptical
aids. Optical aids include:
Telescopes. May be used to read street signs.
Hand magnifiers. May be used to read labels on things at the store.
Stand magnifiers. May be used to read.Prisms. May be used to move the image onto a healthy
part of the retina in some eye diseases.
Closed circuit television (CCTV). For large magnification (e.g., for reading). Nonoptical aids can
include large print books and magazines, check-writing guides, large print dials on the
telephone, and more.For those who are blind, there are enormous resources available to
improve the quality of life.
For the legally blind, financial assistance for help may be possible. Braille and audio books are
increasingly available. Guide dogs provide well-trained eyes and independence. Orientation
and mobility training is available. There are special schools for blind children and access to
disability support through Social Security and private institutions.
Prognosis & Prevention
The prognosis generally relates to the severity of the impairment and the ability of the aids to
correct it. A good low vision exam is important to be aware of the latest low vision aids.
Prevention
Regular eye exams are important to detect silent eye problems (e.g., glaucoma). Left untreated,
glaucoma can result in blindness. Corneal infections can be treated with effective antibiotics.
Cataracts should be removed when they interfere with a person's quality of life.
Primary prevention addresses the causes before they ever begin. Fly control can be
accomplished by simple sanitation methods. Public health measures can reduce the incidence of
many infectious diseases. Vitamin A supplementation (when appropriate) will eliminate
xerophthalmia completely. It is possible that protecting the eyes against ultraviolet (UV) light
will reduce the incidence of cataracts, macular degeneration, and some other eye diseases. UV
coatings can be placed on regular glasses, sunglasses, and ski goggles. Patients should ask their
eye care professional about UV coatings. Protective goggles should also be worn in certain
situations (e.g., certain jobs, sports, even mowing the lawn).
Technology
"The greatest tragedy in life is people who have sight, but no vision.” ---Helen Keller
Some people use different things to help with their visual impairments by using adaptions
such as glasses, Braille, seeing eye dogs, canes, and adaptive computer technology.
Braille - Louis Braille of Coupvray, France invented Braille. While he was at school Braille
wanted to read but could not always have someone to read to him. So he invented a reading
technique for blind people, which was a modification of "Ecriture Nocturne," a code made for
the military by Charles Barbier for soldiers to read at night when there was no light.
Braille is a system of raised dots that a blind person can read with their fingertips. There are
two grades of Braille; grade one and two. Grade one is a little bit harder but will teach the
person the basic letters and short words. Grade two is a combination of letters that forms a
word. For example, the word "Him", is HM. This allows the person to read the Braille faster.
There are many machines that coordinate with the use of Braille, such as the Braille typewriter,
a machine that reads the text and prints it out in Braille, and there are many libraries that now
carry Braille books. There is also Braille printers that allow computer files to be transformed
into Braille, even graphics.
Since Braille was invented it has come a long way and is now helping visually impaired people
have greater access to the non-visually impaired world around them.
Technology Continued
Seeing Eye Dogs: Seeing Eye dogs and canes are used more for helping people
get around from place to place. A Seeing Eye dog is specially trained to help
a visually impaired or blind person get back and forth from work, school, or
even to the neighbor's house. The dogs go to a special school where they
learn to obey traffic lights, veer the person out of the way of poles, and help
him/her down steps. They wear a harness and the owner holds on to it and
tells the dog where to go. Many people like seeing eye dogs for their ability
to get the person where there going pretty fast. Then again, some people
dislike them because if the person wants to go somewhere new, the dog
might not know how to get there. Seeing Eye dogs help people get where
they're going though they are not for everyone.
Canes: Canes are like Seeing Eye dogs, in that they are mobility oriented but
the person uses it by swinging it back and forth to tell if objects are close by.
The cane is one of the earliest forms of getting around for a blind person and
still is widely used today. Over the years we will have new technologies for
blind people but I still feel that the cane will remain one of the leading forms
of transportation for Visually Impaired people.
Activities, Sports, Games,
Toys, Books &
Organization
Pass around activities Handout
Famous People
Louis Braille - Educator, inventor of the Braille alphabet
Ray Charles - was famous throughout the world as a singer and songwriter
Thomas Pryor Gore - U.S. Senator
Helen Keller
Claude Monet - Painter
William Moon - Inventor
Ronnie Milsap - Country singer
John Milton - Author/Poet
Marla Runyan - Olympic Runner
Scott MacIntyre – Singer on American Idol
Stevie Wonder - Singer and musician
Youtube
http://www.youtube.com/watch?v=8q3cS_ilzgk
Resources
http://www.answers.com/topic/visually-impaired
http://library.thinkquest.org/11799/data/blind.html
http://www.brailleinstitute.org/facts_about_sight_loss
http://www.tsbvi.edu/recc/rl.htm#rl28
http://www.tlrf.org/kids_resources_famouspeople.htm