By law, legal blindness is a level of visual impairment that limits allowed activities (e.g., driving) for safety reasons or determines eligibility for government-funded disability benefits such as education, service or monetary assistance.
The U.S. Social Security Administration defines legal blindness thusly:
- Reduced central visual acuity of 20/200 or less in your better eye with the use of the best eyeglass lens to correct your eyesight; or
- Limitation of your field of view such that the widest diameter of the visual field in your better eye subtends an angle no greater than 20 degrees.
In 2009, a report by the National Federation of the Blind found that 1.3 million people in the United States could be categorized as legally blind. A 2004 study by the Eye Diseases Prevalence Research Group stated that in the U.S. nearly 1 million people over the age of 40 were considered legally blind, and another 2.4 million Americans had low vision, meaning their corrected visual acuity was worse than 20/40 in their better eyes. The authors of the latter study estimated that, due to the aging of the U.S. population, the number of legally blind Americans would increase by 70 percent to 1.6 million by 2020, with a similar rise in low vision.
The four leading causes of legal blindness are: age-related macular degeneration, cataracts, diabetic retinopathy and glaucoma. Optic neuritis and neuropathy can also cause legal blindness, as can certain congenital conditions, and kerataconus – a gradual thinning of the cornea – can cause severe vision loss to the point of legal blindness.
For an assessment or for assistance managing and navigating the challenges of legal blindness, please reach out to our highly trained staff and doctors.