Low Vision Information

California Department of Education
1430 N Street
Sacramento, CA 95814



Low Vision Information

Definitions, causes, devices, assessment, and resources.



Low vision is a term used to describe a permanent and significant loss of visual function, including either visual acuity (the ability to see detail), visual field (the ability to see a large area of about 175 degrees), or both. Low vision cannot be corrected with conventional glasses, contact lenses, surgery, or medication.
Low vision is not to be confused with legal blindness, which is defined in federal law as “central visual acuity of 20/200 or less in the better eye with the use of correcting lens. An eye which has a limitation in the field of vision so that the widest diameter of the visual field subtends an angle no greater than 20 degrees is considered to have a central visual acuity of 20/200 or less.”
A central visual acuity of 20/200 means that a person can only see visual detail, such as a letter or word, at a distance of 20 feet that can be seen by a normally sighted person at a distance of 200 feet.
Legal blindness is not necessarily the same as total blindness. All totally blind people are legally blind. Some legally blind persons who have some usable vision are considered to have low vision. There must be some usable vision remaining in the eyes to be considered low vision.
To be eligible for special education, a pupil must have a visual impairment that, even with correction, adversely affects a pupil's learning of curriculum. For educational purposes, the term visually impaired includes: 1) functionally blind students who, because of the severity of their visual impairment, rely basically on senses other than vision as their major channels for learning; and 2) low vision students who use vision as a major channel for learning. A visual impairment does not include visual perceptual or visual motor dysfunction resulting solely from a learning disability.
C.F.R. 404.1581

Low Vision Devices

Collaboration among all professional education and eye care staff in providing coordinated, comprehensive services is critical to achieving the greatest success for students with visual impairment.

Low vision devices work in one of several ways:

  • Control the focus or image clarity
  • Control illumination and contrast
  • Control magnification or size of the image on the retina

Magnification can be achieved by:

  • Relative distance (moving closer to the object)
  • Relative size (physically enlarging the object)
  • Optical (enlarging the image on the retina by passing it through a lens or group of lenses)
  • Electronic projection magnification (enlarging the image on the retina, using projectors and/or computers)


Other kinds of valuable, nonprescription low vision devices are various hand magnifiers, focusable stand magnifiers, loupes, head-borne nonprescription aids, clip-on loupes for near vision, and a large variety of other monocular and binocular distance-vision devices in various magnification ranges and styles to fit individual needs.

Locating A Low Vision Specialist in Your Area

American Foundation for the Blind (AFB)External link opens in new window or tab.

California Optometric AssociationExternal link opens in new window or tab.

California Academy of Eye Physicians and SurgeonsExternal link opens in new window or tab.

California School for the Blind, Low Vision ClinicExternal link opens in new window or tab.

A list of optometrists who have earned special recognition as diplomats in low vision is available by contacting:
American Academy of OptometryExternal link opens in new window or tab.

Other California Agency for Low Vision Services

California School for the BlindExternal link opens in new window or tab.
Main Office
[email protected]

California Department of Health Care ServicesExternal link opens in new window or tab.
Medi-Cal Vision Care program
[email protected]

California Department of RehabilitationExternal link opens in new window or tab.
Blind Field Services
[email protected]

California Department of Social ServicesExternal link opens in new window or tab.
Office of Services to the Blind
[email protected]

Questions: Clearinghouse for Specialized Media and Technology | [email protected] | 916-319-0881 
Last Reviewed: Thursday, April 21, 2022