Today, there are some 180 million people worldwide with visual disability, who are in need of social, vocational, economic or rehabilitative support services. More than 45 million people are blind and cannot walk without aid. Of this 45 million, ninety percent live in developing countries.
According to the World Health Organization, this figure will double over the next 25 years unless there is decisive public health action. It is estimated, however, that more than 80 percent of all blindness cases can be prevented or treated, resulting in the restoration of sight. This requires a greater emphasis on prevention and early intervention and treatment.
In addition to blindness, another 110 million people in the world are considered visually impaired or have what is termed low vision. This means they have visual acuity of less than 20/40 in their better eye even with glasses.
According to the World Health Organization (WHO), cataracts are the leading cause of blindness in the world, accounting for approximately 43 percent of all cases. Glaucoma has recently been ranked second by the WHO, responsible for 15 percent of all worldwide cases of blindness —and the leading cause in the United States with between 2 and 3 million Americans over the age of 40 afflicted. Trachoma, and the resultant corneal scarring, account for the third highest proportion, causing more than 11 percent of all cases of blindness. Onchocerciasis, xerophthalmia, age-related macular degeneration (ARMD) and diabetic retinopathy are the other major causes of blindness. An estimated 1.4 million children in the world are classified as blind. Worldwide the leading cause of childhood blindness is vitamin A deficiency, or xerophthalmia.
The leading causes of blindness in the United States—macular degeneration, cataracts, and glaucoma—will double their impact in the coming years as the 78 million baby boomers in the U.S. reach older adulthood. By the year 2030, twice as many people will be blind as are today and there will be a near doubling of the total cases of glaucoma. Macular degeneration will be the leading cause of blindness. This dramatic increase in age-related eye disease threatens to overwhelm the health care resources of the U.S. and diminish the quality of life for millions.
Visual impairment describes vision that cannot be fully corrected by ordinary prescription lenses, medical treatment, or surgery. The term visual impairment includes conditions ranging from the presence of good usable vision to low vision, to the absence of any sight at all–total blindness. Many terms are used when people refer to visual impairment. Definitions include:
- Severe visual impairment: Severe visual impairment is a term used by researchers at the National Center for Health Statistics (NCHS) to describe visual impairment in people who are unable to read ordinarynewsprint even with correction. This term, used primarily for studying visual impairment in the population,is not used in clinical references by eye care professionals. People with a severe visual impairment may ormay not be legally blind.
- Low Vision: corresponds to visual acuity of less than 6/18, but equal or better than 3/60 in the better eye with best possible correction. Low vision is a clinical diagnostic term used to describe impaired vision thatcannot be improved by conventional eyeglasses, contact lenses, medications, or surgery in which some goodusable vision remains. People with low vision can learn to make the best use of the vision available to them.
- Blindness: visual acuity of less than 3/60 or corresponding visual field loss in the better eye with best possible correction.
- Legal Blindness: Legal blindness defines visual conditions that, when present, connote eligibility for government or other benefits and services. An individual who is legally blind has a visual acuity of 20/200 inthe better eye with the best correction or a visual field of no more than 20 degrees.
Leading Causes of Blindness
The leading causes of blindness in the world are cataract, glaucoma, trachoma, Vitamin A deficiency (under five years of age), Onchocerciasis, diabetic retinopathy, macular degeneration, optic neuropathy, and others. It is estimated that between 40 and 50 percent of these cases can be prevented or treated, resulting in the restoration of sight.
The World Health Organization (WHO) will lead an international alliance of interested parties to work for the global elimination of trachoma, a leading cause of blindness worldwide, and an infectious disease responsible, at present, for at least 15% of the world’s blindness. Almost six million people are already blind or at risk of blindness from trachoma. An estimated 150 million more people have the active disease and require immediate treatment. 10% of the world’s population is at risk of this disease if it is not controlled. Women and children contract blinding trachoma three times more than men do.
Trachoma has been eliminated as a blinding disease from several previously hyperendemic countries and regions, both through significant improvements in the socioeconomic status of populations and through specific control efforts. However, even in some of the countries where trachoma is no longer hyper endemic, residual pockets of blinding trachoma and complications from trichiasis remain.
Today, the disease is found mainly in poor rural areas, including parts of central and South America, most African countries and some countries in the Eastern Mediterranean. Trachoma is still endemic in several Asian countries, but there is a lack of updated information from some major populations, e.g. in India and China.
Trachoma is one of the oldest infectious diseases known to mankind, which dates back several thousand years and was first documented as early as the pharaonic era in Egypt. Trachoma is considered a “community” disease, and is associated with poor socioeconomic conditions: overcrowding, inadequate personal and environmental hygiene and, most significantly, limited access to water and sanitation.
The disease is caused by an organism prevalent in poor communities with limited access to adequate sanitation and water. This microoganism, Chlamydia trachomatis, resembles both a bacteria and a virus and spreads through contact with eye discharge from the infected person (on towels, handkerchiefs, fingers, etc.) and through transmission by eye-seeking flies. Chlamydia trachomatis provokes an inflammatory reaction in the eye with formation of follicles in the conjunctiva. After years of repeated infections, the inside of the eyelids may be scarred so severely that the eyelid turns inwards with eyelashes rubbing on the eyeball. If untreated, this condition leads to blindness.
Trachoma usually begins in childhood, in communities where people live in overcrowded conditions and have limited access to water and health care. Worldwide, over 500 million people are at risk. Education in basic hygiene can help prevent the disease, antibiotics can treat the active disease and surgery ($20) can prevent further vision loss and relieve the constant pain, but the only approach that will have a long-lasting impact is one that includes a far-reaching community education and lasting component.
The SAFE Strategy, developed by WHO, is a community-based, integrated plan of action that includes both prevention and treatment strategies.
- Surgery to correct trichiasis (a simple, 15-minute procedure that can be done in a village setting)
- Antibiotics to treat active infection (tetracycline ointment or in some places, azithromycin)
- Face washing (to remove the discharge which can increase the transmission of the disease)
- Environmental change (to increase access to clean water and better sanitation, and related health education)
Nutritional Blindness is responsible for six percent of the worldwide cases of blindness and affects children under five. Caused by a lack of vitamin A in the diet, results in the death of two million children each year from infectious diseases. It also causes 350,000 to become blind. The remedy is to add vitamin A to the diet – by capsule (50¢ per child/year), through consumption of a diet rich in vitamin A, or by fortification of commonly eaten foods such as sugar.
Refractive Error, or disabling visual impairment, affects 135 million people worldwide. Eye screenings, prescription eyeglasses and simple reading glasses can improve quality of life. An estimated seven million poor children in the United States need vision screening and two million need prescription eyeglasses. Eye screening and distribution of eyeglasses to adolescents in impoverished neighborhoods in the United States can be as low as $22 per child.
What is Braille?
Many blind people listen to books on tape just as seeing people do. Some blind people use magnifiers to help them read. They can also read with their fingers with a special alphabet of raised dots on stiff paper called Braille. Braille was invented by a man named Louis Braille in 1922 who wished to help blind people have the chance to read just like everyone else. Today, it is possible for just about anything in print to be published in Braille. There are Braille typewriters and printers so that blind people can use computers to print out their work in Braille.
Braille is written with a combination of six raised dots on stiff white paper. If you look at the model to the right, you can see how the dots are labeled. In real Braille, they are not labeled or colored in, but for this page it is there to help you learn the dot names.
The dots are named from one to six. By making different combinations of the raised dots, the letters of the alphabet, numbers and punctuation marks can be formed.
How the Blind See in a Living World
Blind people have several aids that help them move without the ability to see. One is to use a special cane, sometimes called a long or white cane because it is longer than the one used by people who have difficulty walking. By sweeping the cane in front of the area they are moving towards, blind people can avoid obstacles and get to where they are going. They are taught other skills such as listening to the sounds the cane makes as it strikes the ground, listening to noises such as traffic to tell if cars are coming and to feel where the sun is to tell direction, etc… The blind learn the routes that they take to work, school, and to places of leisure. They are taught by teachers called mobility instructors who specialize in this kind of teaching.
Another aid for the blind is guide dogs. Guide dogs are specially trained dogs that help blind people by learning routes of travel with them, protecting them from oncoming dangers and generally looking out for the blind person. Guide dogs generally spend one year being raised by a loving family and then are sent to guide dog school to learn the skills necessary for a good guide dog. People who need guide dogs apply to get one and then go to the guide dog training center to learn to work with their particular guide dog. This takes several weeks.
Blind people have learned a number of ways to live in our seeing world and sighted people are often in awe at how little their disability seems to impair their ability to lead a normal life. Since the passage of the American for Disabilities Act (ADA) in 1992, both the government and private companies have started to do their part in making it a little easier. Also, as computers have become a part of our daily lives, they have had an even greater impact on the lives of people with all types of disabilities.
To tell time, blind people use talking watches or watches with Braille markings on them. They also use talking scales that tell them how much they weigh. There are phones with Braille markings (all public phone booths now have Braille keys as well as elevators and other public and private communication and transportation systems) or that tell which keys you have punched as well as phones with large keys.
To fill a glass without spilling, blind people can use a small device with a battery and two wire probes that sits on the lip of a glass or cup. When the liquid gets within an inch or so of the top, a little buzzer goes off, letting the person know that the glass is almost full. To cook in the kitchen and wash and dry clothes: blind people label the appliances and utensils either in Braille or with large print labels. They use recipes printed in Braille and can have specially labeled spice racks.
Blind people organize clothes by putting shoes in specially labeled boxes. They can sometimes tell by feel an item of clothing or use pins on the inside of a pair of pants or blouse to tell colors. They bundle socks together in the wash to keep them together.