Monday, October 20, 2008

What do blind people see?

Blindness is the condition of lacking visual perception due to physiological or psychological factors.

Various scales have been developed to describe the extent of vision loss and define "blindness"[1]. Total blindness is the complete lack of form and light perception and is clinically recorded as "NLP", an abbreviation for "no light perception"[1]. "Blindness" is frequently used to describe severe visual impairment with residual vision. In order 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 blindess[2]. 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 from an object to see it with the same degree of clarity as a normally sighted person could from 200 feet. 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, are fully sightless. The rest have some vision, from light perception alone to relatively good acuity. Those who are not legally blind, but nonetheless have serious visual impairments, possess low vision. source

So for alot of blind people they cannot see things that would be far away but as they come closer it becomes clearer to them...

1 comment:

G F Mueden said...

Glad to dee the definition. Is there a different one for near vision? How do they define it and measure it? I see brick work a block away, but have difficulty reading the paper and word verification this blog requires.