Information and Resource Referral Project

Definitions of Blindness and Low Vision

Page Index
Legal Definitions
World Health Organization Definitions
American Academy of Opthamology Definitions
American Optometric Association Definitions
Deaf Blindness

Legal Definitions in the U.S.

Adults:
Legally Blind - "Central visual acuity 20/200 or less in the better eye with best correction or widest diameter of visual field subtending an angle of no greater than 20 degrees." - Rehabilitation Services Administration (RSA).
Severely Visually Impaired - (RSA) - Visual acuity better than 20/200 but less than 20/70 in the better eye with best correction. Note that in most states 70/200 is required to get a driver's license unless the person is referred to a bioptic drivi ng program for special training. For more information on this program contact B. J. LeJeune at bjmax@ra.msstate.edu.

Children:
(from Scholl, Geraldine (1986) "What does it mean to be Blind? Definitions, Terminology and Prevelance," Foundations of Education for Blind and Visually Handicapped Children and Youth. NY: American Foundation for the Blind . p. 28.)
Blind - Learns through tactile or auditory materials.
Low Vision - Severely visually impaired after correction but can increase visual function with the use of adaptive aids.
Limited Vision - Use of vision limited under average circumstances.

World Health Organization Definitions
Blindness is defined as visual acuity of less than 3/60 (0.05) or corresponding visual field loss in the better eye with best possible correction. (ICD10 Codes 3, 4, & 5)
Low Vision corresponds to visual acuity of less than 6/18 (0.3) but equal to or better than 3/60 in the better eye with best correction (ICD10 Codes 1 & 2)
Low Vision, Severe - Performs visual tasks at a reduced level.
Low Vision, Profound - Difficulty with gross visual tasks.
Near Blind - Vision unreliable.
Blind - Totally without sight.
International Statistical Classification of Diseases - revision 10 (ICD-10). This coding of all diseases includes a five digit code. Levels of visual loss are coded starting with the numbers 1-5. For example, total blindness both eyes is coded 3 69.01. But can also be coded by etiology as juvenile glaucoma 365.14 or 362.74 as retinis pigmentosa. The ICD-10 is used primarily as a reporting mechanism for doctors and physicians and insurance companies and medical services providers use it extensiv ely.
URL: http://www.who.int/inf-fs/en/fact142.html

American Academy of Opthalmology Definitions
Visual Acuity - Acuteness or clarity of vision which is dependent on the sharpness of the retinal focus, the sensitivity of the nervous elements, and the interpretative faculty of the brain. Clinically it is usually measured with the Snellen chart or other similar device.
Visual Impairment - . . . may be mild or severe, but in each case visual performance does not meet the individual's needs.
Legal Blindness - Federal Regulation establishes Legal Blindness: . . . when the best vision obtained in the better eye, is 20/200 or less, or when, despite the activity attained the field of vision of the better eye is 20 degreees or less.
Low Vision - When ordinary eye glasses, contact lenses or intraocular lens implants cannot provide sharp sight, and an individual is said to have low vision . . . although reduced central or reading vision is common, low vision may also result from decreased side (peripheral) vision, a reduction of loss of color vision, or the eye's inability to properly adjust to light, contrast or glare.
URL: http://www.eyenet.org

American Optometric Association Definitions
Partially Sighted - Visual acuity that when corrected is still between 20/70 and 20/200; (a person with 20/70 eyesight can clearly distinguish an object at 20 feet that a person with normal vision can clearly distinguish at 70 feet).
Visual Acuity - (criterion): Certify eligibility for special services or programs - financial aid and tax credits.
Legal Blindness - Visual acuity that cannot be corrected to better than 20/200 and/or restricted field vision less than 20 degrees.
Visual Field Loss - (criterion): Certify eligibility for special services or programs - financial aid and tax credits.
Low Vision - . . . terms used to describe several levels of very limited sight which interfere with a person's daily routine activities, have some residual vision, may have reduced central visual acuity (sharpness of vision), with normal or good pe ripheral (side) vision, may have a very narrow field of view but good central acuity.
URL: http://www.aoanet.org/

Definition of Deafblindness:
"Persons who have sustantial visual and hearing losses such that the combination of the two causes extreme difficulty in pursuit of educational, vocatinal avocational or social goals." Helen-Keller World Conference on Services to
Deaf-Blind Youth and Adults, 1997
"Central visual acuity of 20/200 or less in the better eye with corrective lenses or visual acuity of greater than 20/200 if the visual field is constructed to 20 degrees or less, and a physiological chronic hearing impairment so severe that most spe ech cannot be understood through the ear with optimum amplification. A speech discriminating score of 40% or less would generally indicate such a hearing impairment."
Hellen-Keller National Center for Deaf-Blind
Youth and Adults
"...Children who have auditory and visual handicaps, the combination of which cuases such severe communication and other developmental and educational problems that they cannot be properly accommodated in special education programs solely for the hea ring handicapped child or the visually handicapped child."
Federal Register, February 20, 1975

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Last Modified: Wednesday, December 14, 2005 9:33 AM
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