Blind People

Blind People

Blindness is the condition of lacking visual perception due to physiological or neurological factors. Various scales have been developed to describe the extent of vision loss and define blindness. Total blindness is the complete lack of form and visual light perception and is clinically recorded as NLP, an abbreviation for "no light perception." Blindness is frequently used to describe severe visual impairment with residual vision. Those described as having only light perception have no more sight than the ability to tell light from dark and the general direction of a light source.

To determine which people may need special assistance because of their visual disabilities, various governmental jurisdictions have formulated more complex definitions referred to as legal blindness. In North America and most of Europe, legal blindness is defined as visual acuity (vision) of 20/200 (6/60) or less in the better eye with best correction possible. This means that a legally blind individual would have to stand 20 feet (6.1 m) from an object to see it—with corrective lenses—with the same degree of clarity as a normally sighted person could from 200 feet (61 m). In many areas, people with average acuity who nonetheless have a visual field of less than 20 degrees (the norm being 180 degrees) are also classified as being legally blind. Approximately ten percent of those deemed legally blind, by any measure, have no vision. The rest have some vision, from light perception alone to relatively good acuity. Low vision is sometimes used to describe visual acuities from 20/70 to 20/200.

By the 10th Revision of the WHO International Statistical Classification of Diseases, Injuries and Causes of Death, low vision is defined as visual acuity of less than 20/60 (6/18), but equal to or better than 20/200 (6/60), or corresponding visual field loss to less than 20 degrees, in the better eye with best possible correction. Blindness is defined as visual acuity of less than 20/400 (6/120), or corresponding visual field loss to less than 10 degrees, in the better eye with best possible correction.

Blind people with undamaged eyes may still register light non-visually for the purpose of circadian entrainment to the 24-hour light/dark cycle. Light signals for this purpose travel through the retinohypothalamic tract and are not affected by optic nerve damage beyond where the retinohypothalamic tract exits.

Read more about Blind People:  Signs and Symptoms, Comorbidities, Epidemiology, Research, In Other Animals

Other articles related to "blind, people, blind people":

American Council Of The Blind - Actions - Lawsuit To Make U.S. Currency Accessible
... currency more accessible to blind persons ... failures to design and issue paper currency that is readily distinguishable to blind and visually impaired people." The National Federation of the Blind ... ruling 2-1 that the United States does discriminate against blind people because its paper money consists of bills that are all the same size regardless of denomination ...
Leeds Society For Deaf And Blind People - History
... Atley, convened a public meeting to form Leeds United Institution for the Blind and the Deaf and Dumb (later renamed Leeds Incorporated Institution for the Blind and the Deaf and Dumb) ... The new building incorporated workshops for blind people, a service chapel for deaf people and areas for socialising ... apartments.) More recently, in 1996 the name of the Society changed to Leeds Society for Deaf and Blind People ...
White Cane - History
... Blind people have used canes as mobility tools for centuries ... In 1921 James Biggs, a photographer from Bristol who became blind after an accident and was uncomfortable with the amount of traffic around his home, painted his walking stick white to be more easily ... a national white stick movement for blind people ...
Blind People - In Other Animals
... Statements that certain species of mammals are "born blind" refers to them being born with their eyes closed and their eyelids fused together the eyes open later ... Other animals such as the blind mole rat are truly blind and rely on other senses ... The theme of blind animals has been a powerful one in literature ...
Dorton House - External Reference
... Royal London Society for the Blind Coordinates 51°17′07″N 0°13′08″E / 51.2854°N 0.2189°E / 51.2854 0.2189 Organizations for visually ...

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