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What blindness means

See It Differently

Blindness is a range, not a switch, and many people who are blind see something. This page covers what the words mean, where the legal line sits in the United States, what a white cane signals, and the rights that come with it.

See the rangeWhat the white cane signals

At a glance

  • Legally blind, in the United States20/200 or less in the better eye with correction, or a field no wider than 20 degreesThe Social Security definition, used for benefits and services.
  • Low visionSight that glasses, contacts, medicine or surgery can't fully fixAnd that gets in the way of everyday activities. The National Eye Institute's definition.
  • A red-and-white striped caneMeans the person is deafblindThey may not hear a shouted warning or a car.
  • White Cane Safety DayOctober 15Set by a joint resolution of Congress in 1964; the National Federation of the Blind calls it White Cane Awareness Day.

Blindness is a range

Between full sight and no light at all sit most of the people the word "blind" describes. Where someone is on this line says nothing about what they can do.

  1. Full sight

    With or without glasses

    Standard vision, or vision that glasses or contacts bring back to standard.

  2. Low vision

    Everyday tasks are harder

    Sight that standard treatment can't fully fix. Reading, faces, stairs or night travel take tools and strategies.

  3. Legally blind

    A line drawn for services

    The point at which US law opens benefits, rehabilitation and protections. Many people here read with magnification and travel on their own.

  4. Light perception

    Light and dark, not shapes

    Enough to tell a lit window from a wall, which still helps with orientation.

  5. No light perception

    Total blindness

    No visual input at all. The one most people picture, and only one point on the line.

Why the words matter

"Blind" on a form, "legally blind" at the doctor's office and "blind" in conversation describe different things. For inherited retinal disease, the useful questions are what kind of sight is affected and what that changes day to day, which is what the rest of this page is about.

Kinds of vision loss

Two people with the same label can see very differently, because retinal conditions take different parts of sight.

  • Central vision

    Reading, faces and fine detail get hard while the edges stay. Comes from the macula.

    EXAMPLESStargardt disease, Best disease and other macular dystrophies

  • Side vision

    The outer field narrows, so things at the corners of the eyes disappear first; the center can stay sharp for a long time.

    EXAMPLESRetinitis pigmentosa, Usher syndrome

  • Night vision

    Dim light that others manage becomes unusable; often the first change in rod conditions.

    EXAMPLESRetinitis pigmentosa

  • Color

    Colors fade or vanish when the cones don't work.

    EXAMPLESAchromatopsia, cone dystrophy

  • Light sensitivity

    Bright light is painful or washes everything out; some people see better in dim rooms.

    EXAMPLESAchromatopsia, cone dystrophies

The white cane

A tool first, a signal second. It finds steps, curbs and obstacles before the feet do, and it tells everyone else to give the person room.

Three kinds of cane and the two markings worth knowing. Orange stands in for red. Drawing, not to scale.

  • Long cane

    Reaches the ground a step or two ahead and is swept side to side to find curbs, steps and obstacles. The everyday travel tool, taught by orientation and mobility specialists.

  • Identification cane

    Shorter and lighter; carried to tell others the person has low vision rather than to find obstacles.

  • Support cane

    A walking cane in white, for people who need balance support and want their vision loss to be visible.

  • The markings

    In the United States any white cane, with or without a red band near the tip, signals that the user is blind or has low vision. Red-and-white stripes along the length signal that the person is deafblind, with both sight and hearing affected.

If you meet someone with a cane

Simple courtesies that keep people safe and treat them as adults.

  • Driving, stop fully when a cane user or guide dog is at a crossing. State white cane laws require drivers to yield.
  • Ask before helping, and take no for an answer.
  • Say who you are and speak to the person, not to whoever is with them.
  • Give directions in words: "the door is ahead on your left", not "over there".
  • Never grab an arm, and never touch or move the cane or a guide dog.
  • If the cane is striped, the person may not hear you: a light touch on the arm, then words.

Six things people get wrong

The myth, struck out, and what is true.

  • Myth: Blind means total darkness.

    Reality: Many people who are blind see something: light, shapes, movement, color, or clear detail in one part of the field.

  • Myth: A white cane means the person sees nothing.

    Reality: Many cane users have usable vision and carry the cane for obstacles their sight misses, or to signal in unfamiliar or dim places.

  • Myth: Legally blind means no vision.

    Reality: It is a line drawn for services. Many people past it read with magnification, recognize faces up close and use a phone like anyone else.

  • Myth: You are either sighted or blind.

    Reality: Sight runs along a range, and inherited retinal disease moves people along it slowly, often over decades.

  • Myth: Everyone who is blind sees the same way.

    Reality: Some lose the center, some the edges, some the night, some color. The condition decides, and so does its stage.

  • Myth: People who are blind can't work, read or use technology.

    Reality: With training and tools, people with significant vision loss study, work, raise families and travel. Screen readers, magnification and voice assistants are built into the phones already in their pockets.

Medical Disclaimer

This information is for educational purposes only and does not constitute medical advice. It is not a substitute for seeking medical opinions, nor an endorsement of any treatments, research, or organizations. Trial information is sourced from ClinicalTrials.gov and public press releases. Genetic testing and clinical management should be performed by qualified healthcare professionals, including ophthalmologists and genetic counselors.

Sources

  1. Social Security Administration, 20 CFR 404.1581, Meaning of blindness as defined in the law (statutory blindness: 20/200 or less in the better eye with a correcting lens; visual field no greater than 20 degrees).
  2. National Eye Institute, Low Vision (definition; vision rehabilitation).
  3. National Federation of the Blind, White Cane Awareness Day (joint resolution of Congress, 1964, designating October 15 as White Cane Safety Day).
  4. American Council of the Blind, White Cane Laws for States (state statutes requiring drivers to yield to pedestrians with a white cane or guide dog).
  5. Deafblind UK, Red and white canes (the striped cane as the sign of deafblindness).
  6. National Eye Institute, Retinitis Pigmentosa; MedlinePlus Genetics, Achromatopsia and Stargardt macular degeneration (the kinds of vision loss and example conditions).