Facts About Blindness

Understanding Visual Impairment

What Constitutes Being Legally Blind?

What does it mean to be legally blind? Is it the same as having low vision? Does it mean that these individuals are completely without sight? The terms legally blind and low vision are often used interchangeably, but there is an important difference between the two. The term “legally blind” was created to set government eligibility assistance guidelines for people with visual impairments.

In 1934, the American Medical Association defined “legally blind” as having “central visual acuity of 20/200 or less in the better eye with corrective glasses or central visual acuity of more than 20/200 if there is a visual field defect in which the peripheral field is contracted to such an extent that the widest diameter of the visual field subtends an angular distance no greater than 20 degrees in the better eye” (quoted by Koestler, 1976).

To put this into understandable terms, having a visual acuity of 20/200 means that even with the most powerful corrective lenses available, this person can be no further than 20 feet away from the object to see the details that a person with normal vision (20/20) can see from 200 feet away.

One very important point to remember is that even when the legally blind person is 20 feet away from the object, others with unimpaired vision cannot assume that this person can see all the details that they are able to see.

Additionally, a person with normal vision has a total visual field of 180 degrees for peripheral vision while someone who is legally blind only has the ability to see objects that are located within a 20 degrees visual field.

Glaucoma – Learn More

Glaucoma: normal view vs. view with retinitis pigmentosa

Cataracts – Learn More >>

Cataracts: normal view vs. view with cataracts

Diabetic Retinopathy – Learn More >>

Normal view vs . view with diabetic retinopathy

Macular Degeneration – Learn More >>

normal view vs. view with macular degeneration

Information obtained from The Retina Eye Center www.retinaeyecenter.com, Healthline.com. Please visit the above or the Foundation Fighting Blindness www.blindness.org for more information.

Do’s and Don’ts When Interacting with a Person who is Blind

When speaking with a person who is blind:

  • DO identify yourself, especially when entering a room. Don’t say, “do you know who this is?”
  • DO speak directly to the individual. Do not speak through a companion. Unless they are hard of hearing, they can speak for themselves.
  • DO give specific directions like “the desk is five feet to your right” as opposed to saying “the desk is over there.”
  • DO give a clear word picture when describing things to an individual with sight loss. Include details such as color, texture, shape and landmarks.
  • DO touch them on the arm or use their name when addressing them. This lets them know you are speaking to them, and not someone else in the room.
  • DON’T shout when you speak, they can’t see but often have fine hearing.
  • DON’T be afraid to use words like “blind” or “see.” Their eyes may not work but it is still “nice to see you.”

If you see a blind person who seems to be in need of assistance:

  • DO introduce yourself and ask the person if he needs assistance.
  • DO provide assistance if it is requested.
  • DO respect the wishes of the person who is blind. DON’T insist upon trying to help if your offer of assistance is declined.

If a Blind person asks you for directions:

  • DO use words such as “straight ahead,” “turn left,” “on your right” or use phrases, such as “go approximately 5 feet then turn left and go another 10 feet”.
  • DO use a 12 hour clock when eating with a blind person to tell them where the placement of their food is on a plate; or where their glass is. For example: “Your meat is at 6pm; your glass is at 1pm.”
  • DON’T point and say “go that way” or “it’s over there.”

If you are asked to guide a Blind person:

  • DO allow the person you are guiding to hold your arm and follow as you walk
  • DO move your guiding arm behind your back when approaching a narrow space so the person you are guiding can step behind you and follow single-file.
  • DO hesitate briefly at a curb or at the beginning of a flight of stairs and tell them why you are doing so.
  • DO tell the person you are guiding whether the steps go up or down. DO allow the person you are guiding to find the handrail and locate the edge of the first step before proceeding.
  • DON’T grab the person you are guiding by the hand, arm, or shoulder and try to steer him.
  • DON’T grab the person’s cane or the handle of a dog guide’s harness


  • DO NOT pet, feed or distract a Guide Dog. They are not pets, they are working companions on whom the blind person depends on to guide them SAFELY.
  • DO NOT allow your dog, while on leash, to interact with a Guide Dog – again, the blind person depends on their dog to guide them safely, any distraction can endanger their safety.
  • Distracting a Guide Dog while he/she is working can endanger the life of the blind person.

Thank You to Our Partners & Sponsors

Berger Foundation
The Auen Foundation

Help our mission by Donating Today!

Guide Dogs of the Desert | California