Thunder Dog - Michael Hingson [79]
Blindness: Partial or complete loss of sight with visual acuity of not greater than 20/200 in the better eye with correction or a field not subtending an angle greater than 20 degrees. Blindness may be caused by injury, by lesions of the brain or optic nerve, by disease of the cornea or retina, by pathological changes originating in systemic disorders and by cataract, glaucoma, or retinal detachment. Blindness can be caused by infectious diseases and by dietary deficiencies in underdeveloped countries where medical care is inadequate. Specific kinds of blindness include night blindness that may progress to total blindness, color blindness (an inability to distinguish colors), and snow blindness (a temporary condition caused by the reflection of sunlight on snow).
Braille: Braille is a code in the same way that we understand Morse Code, sign language, and short hand. It is not a different language. Braille consists of “braille cells.” Each cell is two dots wide and three dots high. When the cell is filled, it looks like a rectangle standing on its narrow end. The Braille Code assigns specific meanings to virtually every mathematically possible combination of 1, 2, 3, 4, 5 and 6 dots located somewhere inside that cell, and combinations of up to 4 cells. For ease of reference, the dots are numbered top to bottom down the left side 1, 2, 3, and down the right 4, 5 and 6. Throughout the educational materials and rules, you will see reference to “dots 1, 3, 4” or “dots 2, 5, 6.” Since there are only 64 mathematically possible combinations with one cell, many dot combinations have to serve many functions and have rules governing that function.
Braille, contracted: Braille consists of a standard alphabet and hundreds of abbreviations and contractions. Using such symbols creates contracted braille, saving approximately 20% of the space of non-contracted braille.
Braille display, refreshable: These machines use various approaches to raising and lowering plastic or metal pins through a grid to create braille characters. Some such systems are only for use with a desktop computer while others have the functions of a laptop computer also built in. Some units have but a few braille cells while others actually have enough braille cell space to replicate an entire print monitor.
Braille Embosser: A computer-driven machine pressing braille dots into paper and other thin materials.
Braille, Foreign Language: Most written languages also have a set of braille symbols representing that language. Each language and nation generates its own sets of rules concerning those characters and the formatting of the document itself. In most non-English languages, no short-form or contracted braille is used.
Braille, Grade One: Previous name for the type of braille that is spelled out letter by letter. Now called non-contracted braille.
Braille, Grade Two: Previous name for the type of braille that uses abbreviations and contractions to save space. Now called contracted braille.
Braille Literacy: This term has been adopted by the blindness community in many countries as the central concept for advocating that children be taught good braille skills at an early age. Advocates equate braille literacy with literacy for sighted people and point to some critical statistics to bolster their position. In the United States, unemployment for blind and visually impaired people runs at approximately 73%. Conversely, only 26% of the blind people available for work have jobs. However, among those with good braille skills, 90% have jobs. The logic then runs that if children are taught braille literacy, their opportunities for gainful employment more than triple.
Braille, Paperless: There are machines that use various approaches to raising and lowering