Blindness is a disorder in which a person’s vision is extremely impaired. This can be because of an issue with the eyeballs themselves, or with the structures in the brain that turn light into sight, such as the optic nerve.
However, just as sight comes in a range (some people can see fine unassisted, while others need glasses or contacts), blindness isn’t exactly the same for everyone either. Here’s a look at the definition of legally blind and what it means.
What is Perfect Vision?
Less than half of Americans have perfect vision. Perfect vision means an eye doctor, or ophthalmologist, has diagnosed their eye prescription as “20/20.” But what does that mean? A visual acuity test is a series of lines, each consisting of different letters. As the lines get lower, the letters get smaller. Standing 20 feet away, a patient with perfect eyesight will be able to read the row deemed appropriate -- and that row is the same for everyone. However, not everyone can read that line from 20 feet away; some people can even read that line farther than 20 feet away.
The number before the slash refers to how far from the eye chart the individual being measured is. The number after the slash corresponds to how far away someone with normal (or “perfect”) vision can stand and see what the individual in question is seeing. So someone with 20/30 vision can see at 20 feet what perfect vision can see from 30 feet. Additionally, most people can see 140 degrees around without moving their head. Issues with vision, particularly your peripheral vision, can limit this field of vision considerably.
In many cases, glasses or contacts are sufficient to correct this refractive error -- astigmatism, myopia (can’t see far away), or hyperopia (can’t see close up). Usually, this makes it so you can legally drive a car, read the newspaper, recognize your child’s face, and notice someone walking up beside you. Unfortunately, this isn’t always the case.
What is Legal Blindness?
Being legally blind doesn’t mean you have to have your glasses to read street signs -- but neither does it mean you see absolutely nothing. Legal blindness is especially important to understand if you are seeking disability compensation or other benefits to assist you because of vision loss. The Social Security Administration states that being legally blind, or lacking sufficient sight so as to be considered blind in the eyes of the law, as:
- Having a visual acuity score of 20/200 or less (or can see from 20 feet what normal vision can see from 200 feet) in the eye with stronger vision while wearing corrective lenses, or
- Being able to see no more than 20 degrees from center vision (having inhibited peripheral sight to such a degree that you cannot see past the 20-degree mark while looking forward)
Essentially, even wearing your glasses, the best you can see is 20/200 or the farthest you can see is 20 degrees around.
Through the SSA, you may qualify for benefits to assist you with the cost of living. Even if you do not qualify as legally blind, there may still be ways the SSA can help you. If you are legally blind and in need of assistance, talk to your local branch of the Social Security Administration.
