Definition

Visual Impairment and Blindness

I thought the best place to look for a definition for visual impairment and blindness would be the World Health Organization. There are four levels of visual function as defined by the International Classification of Diseases.

• Normal vision
• Moderate Visual Impairment
• Severe Visual Impairment
• Blindness

Moderate and severe visual impairment are combined into a category called low vision. This catagory also includes blindness.

• Blindness is defined as a lack or dsficiency in visual perception.
• Total blindness is described as a lack of form and visual light perception.
• Legal blindness is defined as a visual acuity of 20/200 or less with the better eye with the best possible visual correction. That means that a visually impaired person would have to stand 20 feet from an object that a person with normal vision could see from 200 feet away.

The majority of people with visual impairments are 65 years of age or older. With our aging population more of the world's population will be at risk of some type of visual impairment. This is a portion of the population that is thought to be less adaptable to their new reality than others. They might not be as readily accepting of any form of assistive technology. It is also estimated that 19 million children under the age of 15 are visually impaired. 1.4 million of these cases being irreversible. The WHO estimates that 12 million cases of visual impairment are due to refractive eooeors that are esaily corrected.