Visual Disorders
Posted on March 4, 2010
Filed Under Personal Injury |
Visual disorders are defined by impairment in visual acuity. One form of a visual disorder is total blindness, which is an inability to distinguish light from dark - resulting in a total lack of vision. A severe reduction in vision is known as low vision or visual impairment which cannot be compensated for by corrective lenses. This will reduce a person’s ability to function at a certain level when attempting to complete certain tasks. Severe visual impairment can also be referred to as “legal blindness” if the best possible visual correction is 20/200 (or worse), in the eye with the best visual acuity. This term can also apply to a person who has a better than 20/200 visual acuity, but possesses a visual field of 20° or less (reduced peripheral vision).
A Snellen chart is a tool that is used to measure visual acuity using letters of different sizes (large ranging down to small) that are to be read (one eye at a time) from a range of 20 feet. The designation of 20/20 (normal) vision is determined by the ability to read the 20 foot line from a distance of 20 feet. If the letters that are read from a distance of 20 ft. need to be larger than the 20 foot line, then that larger chart number is placed under the 20 ft. number. For example, if, at a distance of 20 feet, the smallest line that can be read is the 200 foot line, then that person is said to have a visual acuity of 20/200.
The World Health Organization (WHO) has defined visual impairment using 5 categories:
- Low vision 1 refers to a best corrected visual acuity of 20/70.
- Low vision 2 begins at a best corrected acuity of 20/200.
- Blindness 3 is visual acuity below 20/400.
- Blindness 4 is below 5/300.
- Blindness 5 is no light perception at all (NLP).
- A visual field between 5° and 10° (A normal visual field is approximately 120°) is assigned category 3; less than 5° is assigned to category 4, (this applies even if the tiny spot of central vision has perfect visual acuity).
Please note that this article is for informational purposes only and is not intended as legal advice.
Visual disorders can be progressive and may prevent someone from seeking productive employment. More detailed information, on Social Security claims, can be obtained by contacting the Texas SSDI lawyer Gerard Lynch, serving clients in Beaumont and other Texas cities.
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