“Legally Blind” is a term that was developed to designate people with vision loss severe enough to qualify for government assistance. The term does not indicate total blindness.
There are two components to legal blindness: visual acuity and peripheral vision.
Legally blind means that a person’s best corrected central visual acuity in their best seeing eye is 20/200 or less or that their visual field (peripheral vision) is 20 degrees or less. “Best corrected” means testing vision with corrective lenses in place.
A central visual acuity of 20/200 or worse in the best seeing eye means that a legally blind person must be 20 feet from something to see it as clearly as someone sees that object at 200 feet who has 20/20 visual acuity.
Visual field also determines legal blindness. The standard visual field is 140 degrees without turning one’s head. A legally blind individual has only a 20 degree or less visual field.
The leading causes of legal blindness:
- Age-related macular degeneration (AMD) is a leading cause of vision loss in Americans aged 60 and older. AMD affects the central portion of the retina (macula) and deteriorates central vision.
- Cataracts affect more than half of all Americans 80 years of age and older. Cataracts cloud the lens and blur vision.
- Diabetic retinopathy affects the blood vessels in the back of the retina.
- Glaucoma is increased pressure within the eye that damages the optic nerve. Untreated glaucoma causes visual field loss.
All of these eye diseases have treatments that can preserve vision or slow vision loss if treatment is started early enough.
Low vision devices
There are many low-vision devices that can augment both close and distance vision. Hand-held and desktop or stand-alone magnifiers are helpful for close up viewing and range in price from $20 to $600.
Glasses with binoculars mounted onto the lenses, wearable devices with built-in HD autofocus cameras with HDMI input for TV viewing, and electronic headsets with a forward-facing camera for each eye that beams the images to the peripheral vision of the wearer to compensate for central vision loss. Prices range from $50 to $6,000
State agencies and nonprofit organizations, such as the American Foundation for the Blind (AFB) are places that can assist individuals with low-vision. The AFB was founded in 1921 to ensure that individuals who are blind or visually impaired have access to information, technology, education, and legal services.
Click here for a list of several other nonprofits that help the blind and visually impaired.
Start with a Consultation
Have a low-vision examination with an eye care profession who has training in low vision and who can advise you on the best low-vision aids for your type of low-vision.