Visual Impairment Glossary

Vision impairment and blindness, its causes, and assistive resources come with a huge range of terminology. Browse our glossary to learn the meanings of these terms. 

Fingers type on a BrailleNote touch
Browse the glossary using this index

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Canaan Barrie

Canaan Barrie signs involve touching - on the body or hands - or movements close to the child.
Canaan Barrie is a system of communication through movement and touch, for children with multiple disabilities and a visual impairment who cannot communicate verbally or through traditional sign language.
The language was created by Mary Lee, a teacher at the Royal Blind School in Edinburgh, along with her former colleague Lindi McWilliam.

Contrast Sensitivity

Contrast sensitivity is an important measure of visual function, especially in situations of low light, fog or glare, when the contrast between objects and their background often is reduced.

Cortical Visual Impairment

Cortical Visual Impairment (CVI) refers to visual problems a child or adult may experience due to damage to the parts of the brain that deal with vision.  CVI can be referred to as 'Cerebral Visual Impairment', 'Cognitive Visual Impairment' or 'Visual Processing Disorder'.