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www.blindcharity.org
About Being Blind
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What is Blindness and Visual Impairment? What all blind people have in common is that their vision cannot be corrected and their vision makes it more difficult to do major life activities such as driving, etc. This can also be called visual impairment. Legal blindness is defined in several ways. One is that a person has vision of 20/200 or less. This means that this person sees at 20 feet that a normally sighted person can see at 200 feet. Many people have this condition and it can be fixed with glasses. A person who is blind in this way has vision cannot be corrected with glasses. Another way a person can be blind is to not have a total "visual field". This means that a person cannot see the whole scene as a normally sighted person can. This is measured in degrees. A person with a visual field of less than 20 degrees is considered legally blind. Normally sighted people have a visual field of 180 degrees in a normal eye. Some people are what is called colour blind. This means that they do not see colours as most people see them. Although they are called colour blind, they are not really legally blind and they can usually drive, and do things more easily than someone who is legally blind. Most blind people have a little sight of some sort or can sense light. However, their vision may make it difficult to recognise people by sight, read easily, or makes them have problems with different lighting etc. Many of them have what is considered low vision and use magnifiers, special lamps and other visual aids to allow them to use the sight they have. Considerations: Blindness can be partial, with loss of only part of the vision. It can also be complete, in which case there is no perception of light. People worse than 20/200 vision are considered legally blind. Blindness has many causes. Accidents, diabetes, and macular degeneration account for most blindness in the United States and other developed countries. Worldwide, vitamin A deficiency is the leading cause of blindness. Common Causes: Accidental trauma to the eyes (such as chemical burns, or injuries from bungee cords, fishing hooks, racket ball, fireworks, and similar objects) Diabetes, Vitamin A deficiency, Basal cell nevus syndrome, Tay-Sachs disease, Retinitis pigmentosa, Retinoblastoma, Lead poisoning, Optic glioma, Glaucoma, Trachoma (Chlamydial conjunctivitis) Other (more rare) causes: Jansky-Bielschowsky syndrome, Krabbe disease, Retrolental fibroplasia, Achromatopsia, Albers-Schonberg (osteopetrosis), Alpers diffuse cerebral degeneration, Anophthalmos, Batten-Mayou, Cockayne syndrome, Cryptophthalmia, Gonococcal ophthalmia, Kufs'disease, Leber congenital amaurosis, Niemann-Pick disease, Norrie's disease, Onchocerciasis (river blindness), Refsum syndrome, Scholz disease, Trisomy-13, Vogt-Spielmeyer Note: There are other causes of blindness. This list is not all inclusive, and the causes are not presented in order of likelihood. The causes of this symptom can include unlikely diseases and medications. Furthermore, the causes may vary based on age and gender of the affected person, as well as on the specific characteristics of the symptom such as quality, time course, aggravating factors, relieving factors, and associated complaints. Use the Symptom Analysis option to explore the possible explanations for blindness, occurring alone or in combination with other problems. Home Care: V Safety and the ability to dress, eat, and function independently are of prime importance to a person with blindness. Call Your Healthcare Provider if: partial or complete blindness develops in one or both eyes. sudden visual loss occurs. What to Expect: The medical history will be obtained and a physical examination performed. Medical history questions documenting blindness in detail may include: Time pattern When did this begin? Did it occur suddenly or gradually? Does it occur only occasionally? How often? How long does it last? When does it occur, in the evening, morning, or all the time? Quality Is the blindness complete? Is there any residual vision--for example, can light and dark be distinguished? Are both eyes affected? Other symptoms What other symptoms are also present? Is there eye pain? Is there a headache? Additional information What medications are being taken? Is there a family history of diabetes? Have you had an injury to the eye or head? A routine eye examination will be performed. The health care provider will check visual acuity, eye movements, pupils, back of the eye (ophthalmoscopy), and eye pressure (tonometry) when indicated. An overall medical evaluation will be done if indicated. After seeing your health care provider: You may want to add a diagnosis related to blindness to your personal medical record. |