En esta recomendación se intenta definir el concepto de baja visión:
“Low vision” refers to visual impairments other than blindness. Other terms, such as “partially sighted” and “sight impaired”, are used in different contexts. Some governments and organizations such as the World Health Organization (WHO) define categories of low vision based on specific levels of visual acuity and field of vision. Visual acuity is the clarity or sharpness of vision. Field of vision is the area a person can see when their eyes are fixed in one position.Y se describen cinco categorías de baja visión que influyen en el uso de la Web:
In many contexts, low vision only includes impairments that are not corrected with regular glasses, contact lenses, medicine, or surgery. For example, an inability to focus on objects close to the viewer but that can be overcome with reading glasses is not considered low vision in some disability rights contexts. In these contexts, low vision is often defined as visual impairment that interferes with a person’s ability to perform everyday activities.
In some contexts, such as social program benefits, people are classified as having low vision or being “legally blind”. Many people who are legally blind have some usable vision, and can read some text when it is displayed optimally for them.
In considering user needs, this document uses a broad scope of low vision to include all visual impairments except significant blindness — including impairments from aging, “color blindness”, and impairments that are often categorized as legally blind yet people have sufficient vision to see user interfaces in some situations. This document does not include all issues that are also relevant for people who are totally blind. It does include several issues that overlap with the needs of some people with cognitive disabilities.
- Visual acuity (clarity)
- Light sensitivity
- Contrast sensitivity
- Field of vision
- Color vision