What is low vision?

Low vision is alternatively a general term used to describe lowered visual acuity, and a specific legal term in Canada and the United States used to designate someone with vision of 20/70 or less in the better eye with correction. it is a subspecialty within the professions of optometry and ophthalmology] dealing with individuals who have less than (sub)normal vision even with the most accurate conventional prescription available. It can be a result of either congenital or acquired factors. An example of the former is Leber's congenital amaurosis and of the latter age related macular degeneration.

Some people who fall into this category can use their considerable residual vision - their remaining sight - to complete daily tasks without relying on alternative methods. The role of a low vision specialist is to maximize the functional level of a patient's vision by optical or non-optical means. Primarily, this is by use of magnification in the form of telescopic sytems for distance vision and optical or electronic magnification for near tasks.

Impaired vision with a significant reduction in visual function which is not correctable with conventional glasses or contact lenses. Term usually used to indicate vision of less than 20/200.

Vision can be hazy with cataracts, blurred or partially obscured in the central visual zone with macular degeneration, and distorted or blurred with diabetic retinopathy. People with glaucoma or retinitis pigmentosa can lose peripheral vision and have difficulty seeing at night.

Some states have specific definitions of low vision that are used to qualify persons for support services or medical assistance.