Difference Between Low Vision, Legal Blindness, Visual Impairment And Blindness. - Health - Nairaland
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| Difference Between Low Vision, Legal Blindness, Visual Impairment And Blindness. by Doctorfitz: 6:58am On May 04, 2017 |
Facts about Low Vision and Legal Blindness Most surveys and studies indicate that the majority of people with vision loss are adults who are not totally blind; instead, they have what is referred to as low vision. You may have heard the terms "partial sight" or "partial blindness" also used to describe low vision. Those descriptions are no longer in general use, however. Here is one definition of low vision, related to visual acuity: Low vision is a condition caused by eye disease, in which visual acuity is 20/70 or poorer in the better-seeing eye and cannot be corrected or improved with regular eyeglasses. (Scheiman, Scheiman, and Whittaker) Snellen Eye Chart The smelled Eye Chart is a testchart that is used by ophthalmologists and optometrists to measure a person's distance visual acuity. It contains rows of letters, numbers, or symbols printed in standardized graded sizes. Your eye doctor will ask you to read or identify each line or row at a fixed distance (usually 20 feet), although a 10-foot testing distance is also used. A Functional Definition of Low Vision Not all eye care professionals agree with an exclusively numerical (or visual acuity) description of low vision. Here's another – more functional – definition of low vision: Low vision is uncorrectable vision loss that interferes with daily activities. It is better defined in terms of function, rather than [numerical] test results. (Massof and Lidoff) In other words, low vision is "not enough vision to do whatever it is you need to do," which can vary from person to person. Most eye care professionals prefer to use the term "low vision" to describe permanently reduced vision that cannot be corrected with regular glasses, contact lenses, medication, or surgery. If you have low vision, it is necessary to have a different kind of eye examination that uses more detailed tests to determine what you can and cannot see. Low Vision vs. Legal Blindness "Legal blindness" is a definition used by the United States government to determine eligibility for vocational training, rehabilitation, schooling, disability benefits, low vision devices, and tax exemption programs. It's not a functional definition and doesn't explain very much at all about what a person can and cannot see. Part 1 of the U.S. definition of legal blindness states this about visual acuity: A visual acuity of 20/200 or less in the better-seeing eye with best conventional correction (meaning with regular glasses or contact lenses). This is a 20/200 visual acuity measurement, correlated with the Snellen Eye Chart (pictured above): If you can only read line 1 (the big "E"  from 20 feet away while wearing your regular glasses or contact lenses, the doctor records your vision (or visual acuity) as 20/200 with best correction.OR a visual field (the total area an individual can see without moving the eyes from side to side) of 20 degrees or less (also called tunnel vision) in the better-seeing eye. Visual Impairment Much like low vision, there are many different definitions of visual impairment. "Visual impairment" is a general term that describes a wide range of visual function, from low vision through total blindness. Here is an example of the variations in the term "visual impairment" or "visually impaired" from the World Health Organization Levels of Visual Impairment: Moderate Visual Impairment: Snellen visual acuity = 20/70 to 20/160 Severe Visual Impairment: Snellen visual acuity = 20/200 to 20/400 OR visual field of 20 degrees or less Profound Visual Impairment: Snellen visual acuity = 20/500 to 20/1000 OR visual field of 10 degrees or less Like the term "legal blindness," "visual impairment" is not a functional definition that tells us very much about what a person can and cannot see. It is a classification system, rather than a definition. Light Perception and Light Projection These terms describe the ability to perceive the difference between light and dark, or daylight and nighttime. A person can have severely reduced vision and still be able to determine the difference between light and dark, or the general source and direction of a light. The stereotypical assumption – that people who are blind or have low vision live in a type of "blackness" that sighted people see when they close their eyes – is generally not accurate. Although every person sees differently, including persons with low vision, an individual who has light perception/projection can perceive the presence or absence of light. Some people describe light perception as knowing when a room light is on or off, or being able to walk toward a lighted lamp on a table in an otherwise darkened room. Total Blindness Total blindness is the complete lack of light perception and form perception, and is recorded as "NLP," an abbreviation for "no light perception." Few people today are totally without sight. In fact, 85% of all individuals with eye disorders have some remaining sight; approximately 15% are totally blind. N. B. This is to say not everyone is totally blind,with adequate,swift attention and seeing a specialist miracles can happen... KNOWLEDGE IS POWER |
| Re: Difference Between Low Vision, Legal Blindness, Visual Impairment And Blindness. by Doctorfitz: 7:02am On May 04, 2017 |
A living room viewed through a constricted visual field.
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| Re: Difference Between Low Vision, Legal Blindness, Visual Impairment And Blindness. by Doctorfitz: 7:03am On May 04, 2017 |
The difference between a normal view and a constricted visual field (view)
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| Re: Difference Between Low Vision, Legal Blindness, Visual Impairment And Blindness. by Doctorfitz: 7:07am On May 04, 2017 |
Normal vision versus legally blind vision
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| Re: Difference Between Low Vision, Legal Blindness, Visual Impairment And Blindness. by LordIsaac(m): 7:12am On May 04, 2017 |
Nice |
| Re: Difference Between Low Vision, Legal Blindness, Visual Impairment And Blindness. by Doctorfitz: 7:13am On May 04, 2017 |
Some people you term blind can still identify white and black
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| Re: Difference Between Low Vision, Legal Blindness, Visual Impairment And Blindness. by Doctorfitz: 7:16am On May 04, 2017 |
Snellen eye chart. It can be in feets or metres (20ft)/(6m) Cc. Dominique, sissy3,ishilove,mynd44
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| Re: Difference Between Low Vision, Legal Blindness, Visual Impairment And Blindness. by Doctorfitz: 8:27am On May 04, 2017 |
LordIsaac: Yes. |
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