Low Vision

Most people classified as blind still have some ability to see. While their vision may be significantly impaired, they can discern light, shapes, or other figures. The term “low vision” refers to a class of visual impairment that cannot be corrected by glasses or contact lenses. Low vision may be the result of any one or more of several conditions, and actual visual abilities may vary by individual. A thorough assessment by an eye care provider can help you determine the severity of your visual impairment and identify potential avenues for treatment.

What Is Considered Low Vision?

The threshold for being considered “legally blind” is met if a person has vision that cannot be corrected to better than 20/200. The World Health Organization defines low vision by degree of impairment. A person whose best corrected vision (in his or her best eye) is 20/70 to 20/160 is considered to be moderate low vision; vision in the 20/200 to 20/400 range is considered severe low vision; from 20/500 to 20/1,000 is profound low vision; and less than 20/1,000 is near total blindness. Only a person who cannot discern any light at all is considered to be totally blind.

So how does this affect you? If you have a condition that prevents your visual abilities from being corrected to near 20/20, you may have low vision. A significant diminution of your visual field, or lack of peripheral vision, is also considered low vision.

What Causes Low Vision?

Low vision does not refer to a single type of vision loss. Rather, it is a cluster of conditions that cause significant impairment visual abilities. Common causes of low vision include macular degeneration, retinal detachment,diabetic retinopathy, cataracts, and glaucoma. Many of these conditions come on or get worse with age, and older adults are more likely to have low vision. However, injuries to the eye, traumatic brain injury, and some genetic conditions can cause low vision at any age.

Diagnosis and Treatment

A thorough optometry exam is the best way to find out if you suffer from low vision. Your eye care provider will test your visual acuity, ability to detect color and contrast, and visual fields. Although by definition, low vision cannot be corrected by prescription glasses or surgery, there may be therapeutic options available to help you continue activities of daily living. Magnifying devices, using large-print materials, and increasing contrast when using computers or other devices may assist you in performing everyday activities. Other aids, such as audiobooks or talking watches, may also be helpful. Discuss your visual impairment with your eye care provider and he or she can help you come up with a plan to improve your quality of life despite low vision.