Low vision, or vision impairment, is a term used to describe varying degrees of vision loss, up to but not including total blindness, caused by disease, trauma, or a congenital disorder. Vision loss may be due to:
or commonly two or more of the above.
Many agencies define low vision as either
However, a more functional definition is that low vision comprises any vision loss that adversely affects the performance of daily activities.
Low vision must not be confused with legal blindness which is defined as:
A patient who is legally blind but has some vision would be considered "Low Vision," but many patients with "Low Vision" are not legally blind. Legal blindness of 20/200 is certainly not a complete loss of sight, which is considered as total loss of all vision (no light perception). In fact, if placed on a continuum between normal vision and no light perception, legal blindness would be closer to normal sight. Thus a person can be "legally blind," but still function relatively well visually, although constrained by the inability to read unless they have low vision rehabilitation, and by the inability to meet visual requirements for driving.
People with more severe or with total visual loss require non-visual solutions for their disability. This Low Vision website is primarily designed to aid individuals with partial sight.