What Does It Mean to Be Legally Blind?

When Your Vision Can't be Corrected

Legally Blind
Clarissa LeahyCollection/The Image Bank/Getty Images

 A person is considered to be legally blind if he or she has a best-corrected vision of 20/200 in their best-seeing eye.

Many people feel that they are legally blind because when they remove their glasses or contact lenses, they cannot see a foot in front of their face. However, when they put on their vision correction, they can see 20/20. As long as you can be corrected to 20/20 with some visual aid, you are not considered legally blind.

Did you know that "legal blindness" is based upon the best level of vision that you can achieve or the best vision you can be corrected to? Most government agencies and health care institutions agree that legal blindness is defined as one of the following:

  1. Legal blindness is defined as visual acuity of 20/200 or worse in the best-seeing eye.
  2. A visual field that is limited to only 20 degrees.

What does "legally blind" really mean?

Being legally blind means that your best-seeing eye cannot be corrected with glasses or contact lenses to any better than 20/200. The best way to understand this is to think about a normal person with 20/20 vision. This person is able to stand 200 feet away from an object and see the finest detail, whereas the legally blind person would have to move all of the way up to 20 feet to see the same detail. A legally blind person has difficulty seeing objects very far away or very close.

If a person has a visual field of only 20 degrees, considered tunnel vision, he or she can be considered legally blind. A normal person has a visual field of 180 degrees. People with a limited visual field can see central detail but can't see someone standing right next to their own shoulder. These people have difficulty with mobility, as safe driving is nearly impossible.

Walking into a dark movie theater can also be a major problem.

The definition of legal blindness was developed to help people receive government assistance. Also, as you can imagine, the department of motor vehicles (DMV) has to have some way of measuring vision in order to keep our roads and highways safe.

Other Terms Related to Vision

The American Foundation for the Blind gives the following definitions related to vision impairments:

  • Vision loss refers to people who have trouble seeing, even when wearing glasses or contact lenses.
  • Clinically diagnosed vision loss is determined by an optometrist or ophthalmologist using dilated eye exams and standard measurement tools.
  • Self-reported vision loss is when a person perceives reduced visual ability and recognizes its effect on daily functioning.
  • Total blindness refers to an inability to see anything with either eye.
  • Low vision is a term often used interchangeably with visual impairment and refers to a loss of vision that may be severe enough to hinder an individual's ability to complete daily activities, including reading, cooking and driving.



American Foundation for the Blind, http://www.afb.org/info/blindness-statistics/key-definitions-of-statistical-terms/25, 2008

Continue Reading