What Is Legally Blind? 20/200 Vision and the US Definition
In the United States, "legally blind" means a central visual acuity of 20/200 or worse in the better eye with the best glasses or contact lenses, or a visual field of 20 degrees or less. That is the definition of blindness in the Social Security Act, and the IRS and the Library of Congress use the same two numbers. It is a line drawn for benefits and services, not a description of what someone sees: Social Security says very few people who meet it are totally blind.
Below: the exact wording, what 20/200 and 20 degrees mean in plain words, why glasses count, how the term differs from low vision, visually impaired, partially blind and totally blind, what the definition is used for, and how many Americans it covers. Official pages were checked on October 28, 2026. This article explains definitions; it isn't legal or medical advice.
Key points
- Two tests, and either one is enough: sharpness of 20/200 or worse in the better eye with correction, or a visual field of 20 degrees or less.
- Glasses and contact lenses count. Vision is measured with the best correction, so eyes that see poorly without glasses but well with them are not legally blind.
- It's about the better eye. Losing the sight of one eye doesn't meet the definition if the other eye sees better than 20/200 with correction and has a field wider than 20 degrees.
- Most legally blind people see something. Social Security says "very few" of them are totally blind.
- Other words mean other things. Low vision, visually impaired and totally blind are defined by other organizations, and the World Health Organization's "blindness" is stricter than the US legal line.
- What it's used for: Social Security disability rules, a higher standard deduction from the IRS, and the free National Library Service. State job programs use their own criteria.
Legally blind, low vision, visually impaired: the terms at a glance
| Term | What it means | Who defines it |
|---|---|---|
| Legally blind | 20/200 or worse in the better eye with correction, or a visual field of 20 degrees or less | Social Security Act; the IRS and the NLS use the same numbers |
| Totally blind | No perception of light or of shapes | American Foundation for the Blind (AFB) |
| Low vision | Vision loss that glasses, contacts, medicine or surgery can't fix, and that makes everyday activities hard | National Eye Institute (NEI); AFB adds 20/70 or worse in the better eye |
| Visually impaired | A general term for anything from low vision to total blindness | AFB |
| Partially blind | An older term that AFB says is no longer in general use | AFB |
| Blindness (WHO) | Visual acuity worse than 3/60, about 20/400, in the better eye | World Health Organization, in line with ICD-11 |
The exact US definition of legally blind
Social Security calls it statutory blindness, because it comes from the law itself. This is the current wording in SSA's operations manual for claims staff (POMS DI 26001.001), in effect since December 2014:
"Sections 216(i)(1) and 1614(a)(2) of the Social Security Act (Act) define blindness as central visual acuity of 20/200 or less in the better eye with the use of a correcting lens. The Act also provides that we consider an eye that has a visual field limitation such that the widest diameter of the visual field subtends an angle no greater than 20 degrees as having a central visual acuity of 20/200 or less."
The same manual adds that SSA uses "the best-corrected visual acuity for distance in the better eye." The two sections it cites are the ones behind Social Security disability benefits (section 216) and Supplemental Security Income (section 1614), so one definition serves both programs. The original text is in 42 U.S.C. 416(i)(1).
In plainer words, from SSA's fact sheet for blind workers: "Social Security considers you to be blind if your vision cannot be corrected to better than 20/200 in your better eye or if your visual field is 20 degrees or less in your better eye."
"Legally blind" is the everyday name for this. The law sets two separate tests, and meeting either one is enough:
- Acuity: how sharp the center of your vision is, measured with the best correction. The line is 20/200, and anything worse also counts.
- Visual field: how wide an area you can see. The line is 20 degrees across at the widest point.
What 20/200 vision means
An eye chart score is a fraction. The first number is how far you stand from the chart, 20 feet in the US. The second number is the distance from which a person with normal vision can read the same line. The World Health Organization explains it with the metric version of the chart: a score of 6/18 means that, standing 6 meters away, a person reads a letter that someone with normal vision could read from 18 meters. Normal vision is 6/6, which is 20/20 in feet.
So 20/200 vision means that from 20 feet away you can read what a person with 20/20 vision can read from 200 feet. On a standard chart, AFB puts it this way: you can read only the top line, the big E, from 20 feet, while wearing your regular glasses or contact lenses.
"20/200 or less" includes 20/200 itself and every worse score, like 20/400. A score of 20/100 is better than the legal line, so on acuity alone that eye isn't legally blind.
Legally blind without glasses? Why glasses and contacts count
"Legally blind without glasses" is a common search, but the legal definition doesn't work that way. The law says "with the use of a correcting lens," SSA uses the best-corrected acuity, and AFB spells it out as the best conventional correction, "meaning with regular glasses or contact lenses."
That means someone who can't read the big E without glasses, but sees clearly with them, is not legally blind. Very blurry vision that glasses fix is a different thing from vision that glasses can't fix. The CDC counts the two separately: in its estimates for 2024, 25.02 million people in the US had vision loss that could improve to 20/20 or better with the right lenses (CDC VEHSS).
The IRS adds one detail in Publication 501: if your vision can be corrected past the limits only with contact lenses you can wear just briefly, because of pain, infection or ulcers, you can still take the higher deduction for blindness if you otherwise qualify.
The World Health Organization's surveys take a different approach. They measure people as they arrive at the exam, with the glasses they usually wear, so someone whose glasses fully correct their vision is counted as having no vision impairment.
Visual field: the 20-degree rule
Your visual field is the whole area you can see without moving your eyes, according to AFB. A person can have sharp 20/20 vision in the center and still be legally blind, if what they see around that center is so narrow that it spans 20 degrees or less at its widest. The law treats that eye as if it had 20/200 acuity. AFB calls a field like this tunnel vision.
This is why two legally blind people can see in very different ways. The National Eye Institute lists several kinds of low vision: losing the center of your vision, losing the edges, not seeing in low light, and blurry or hazy vision. One person may miss what's straight ahead and see around it; another may see only a small area straight ahead. What different blind people actually see, from light and shapes to nothing at all, is covered in what do blind people see?
Legally blind vs totally blind, low vision, visually impaired and partially blind
These words get used as if they were the same. They aren't, and different organizations define them.
Totally blind
AFB defines total blindness as the complete lack of light perception and form perception: no light and no shapes. Legal blindness is a much wider group. In SSA's words, "Very few people who meet this definition experience total blindness."
Low vision
The National Eye Institute says low vision "is a vision problem that makes it hard to do everyday activities," and that "It can't be fixed with glasses, contact lenses, or other standard treatments like medicine or surgery." AFB adds a number: acuity of 20/70 or worse in the better eye.
Put the two side by side and you can see the overlap. Someone with 20/100 vision after correction has low vision by AFB's description, but isn't legally blind. Someone at 20/400 has low vision and is legally blind too.
Visually impaired
AFB calls "visually impaired" a general term covering a wide range, from low vision through total blindness. It's an umbrella word, not a measurement. That's the answer to "visually impaired meaning": it includes legally blind people, but also many people who are not.
Partially blind
AFB lists "partial sight" and "partial blindness" among older descriptions that are no longer in general use. People still search for "partially blind", and they usually mean someone who has some sight but not enough. The closest current terms are low vision or visually impaired. In tax law, the IRS speaks of people who "aren't totally blind" but meet the 20/200 or 20-degree limits.
Types of visual impairment
There are two common ways to sort vision impairment: by how severe it is, and by which part of vision is affected.
By severity, the World Health Organization's classification, which is in line with the ICD-11, uses visual acuity in the better eye (World report on vision, 2019, Box 1.2). The US notation is the equivalent listed in the ICD-11 table:
| WHO category | Visual acuity in the better eye | In US notation |
|---|---|---|
| Mild vision impairment | Worse than 6/12, down to 6/18 | Worse than 20/40, down to 20/70 |
| Moderate vision impairment | Worse than 6/18, down to 6/60 | Worse than 20/70, down to 20/200 |
| Severe vision impairment | Worse than 6/60, down to 3/60 | Worse than 20/200, down to 20/400 |
| Blindness | Worse than 3/60 | Worse than 20/400 |
| Near vision impairment | Worse than N6 or M 0.8 at 40 cm | The same small-print test at about 16 inches |
WHO also counts severe vision impairment and blindness by visual field, when it narrows to less than 20 degrees or less than 10 degrees in the better eye.
Notice where the US line falls. WHO's "blindness" starts at worse than 20/400, so many people who are legally blind in the US are counted as having severe vision impairment in WHO statistics, and someone at exactly 20/200 falls in WHO's moderate band. Neither system is wrong; they serve different purposes: the US definition sets eligibility for programs, and WHO's categories are a classification for health statistics.
By the part of vision affected, the NEI's list above is the practical one: central vision loss, peripheral vision loss, night blindness and blurry or hazy vision. Different eye conditions affect vision in different ways, which is why the label "legally blind" tells you so little about how a particular person sees.
What being legally blind is used for in the US
Meeting the definition doesn't by itself give anyone a benefit: each program has its own application, rules and paperwork. This is what the official pages say.
Social Security disability benefits (SSDI and SSI)
SSA uses the statutory definition for both Social Security disability benefits and Supplemental Security Income, as the manual quoted above shows. Being blind changes how work and earnings are treated:
- A higher earnings limit. SSA's limit on "substantial gainful activity" is higher for blind people on Social Security disability: $2,830 a month in 2026, compared with $1,690 for people who aren't blind. For 2027 the limits are $2,950 and $1,770 (POMS DI 10501.015, revised October 15, 2026).
- SSI works differently. The same manual says blind people under SSI are not subject to those earnings limits.
- Work expenses. Under SSI, SSA's fact sheet says Social Security can subtract the cost of reasonable expenses you need for work. These Blind Work Expenses apply only under SSI.
The IRS: a higher standard deduction
The IRS says that if you are blind on the last day of the year and don't itemize deductions, you're entitled to a higher standard deduction. If you aren't totally blind, Publication 501 asks for a certified statement from an eye doctor (an ophthalmologist or optometrist) saying that you can't see better than 20/200 in the better eye with glasses or contact lenses, or that your field of vision is 20 degrees or less. You keep the statement in your records.
For 2025 returns, the extra amount is $2,000 for a single or head-of-household filer and $1,600 for each blind spouse on a married return. It adds on top of the extra amount for being 65 or older.
The National Library Service: free braille and talking books
The National Library Service for the Blind and Print Disabled, part of the Library of Congress, is "a free braille and audio book library service." Books can be downloaded or mailed to your door for free, and most services run through a network of cooperating libraries.
Legal blindness is one way in, with the same 20/200 and 20-degree numbers, certified by a "competent authority" such as a doctor, an optometrist or a nurse (or a librarian, if none of those is available). It isn't the only way: NLS also serves people whose vision, even with correction, keeps them from reading standard print, and people with physical or reading disabilities.
State vocational rehabilitation
States run vocational rehabilitation (VR) programs for people with disabilities who want to work, with federal grants from the Rehabilitation Services Administration. Eligibility is not tied to legal blindness: RSA says a person must have "a physical or mental impairment that results in a substantial impediment to employment", and must require VR services and be able to benefit from them. Some states have a separate VR agency for people who are blind.
How many Americans are legally blind or visually impaired?
No source we checked counts legally blind Americans exactly. Two official estimates come close, from different angles:
- The CDC estimates that in 2024, 7.15 million people of all ages in the US had vision of 20/32 or worse in their better eye even with the best correction. Of them, about 710,000 had 20/200 or worse, the acuity half of the legal definition. The CDC notes that its estimates don't account for visual field loss, so people who are legally blind by visual field alone aren't in that number (CDC VEHSS, page reviewed August 2026).
- The American Community Survey asks people whether they are blind or have serious difficulty seeing even with glasses. In the 2024 survey, about 9 million people answered yes: 0.7 million children, 4.6 million adults aged 18 to 64 and 3.7 million aged 65 or older, according to AFB's analysis. It's a self-reported answer, not an eye exam.
And how many of them read braille? Nobody measures it today. We traced the "10%" figure everyone repeats in is braille dying?
Reading and technology with little or no vision
Because most legally blind people have some sight, reading looks different from one person to the next: large print and magnification, audio, a screen reader, braille, or a mix. Our guide to how blind people read covers each one.
- Screen readers read a computer or phone screen aloud and are built into every major system: see screen readers for the blind.
- Refreshable braille displays show the screen in braille, one line at a time: see refreshable braille displays.
- Phone apps describe scenes, read print and identify money: see apps for blind and visually impaired people.
Braillito, our app, teaches the braille cells in lessons with exercises you play, with lives, levels and a daily streak: 59 lessons in 8 worlds in English. It also has a translator, a dictionary and a cell builder. Braillito is a subscription with no free version; depending on the plan, it starts with a free trial or a discounted first period, if it's your first subscription (is Braillito free?). Get Braillito.
Frequently asked questions
What is considered legally blind?
In the US, a person is legally blind if the better eye sees 20/200 or worse with the best glasses or contact lenses, or if its visual field is 20 degrees or less. That's the Social Security Act's definition of blindness, and the IRS and the National Library Service use the same numbers.
Is 20/200 vision legally blind?
Yes, if it's the best the better eye can see with glasses or contacts. The law says "20/200 or less," so 20/200 itself counts. If glasses bring that eye to better than 20/200, the acuity test isn't met.
Can you be legally blind without glasses?
Not in the legal sense. The definition is measured with the best correction, so vision that's 20/200 or worse only without glasses doesn't count. The IRS makes one exception for contact lenses that can be worn only briefly because of pain, infection or ulcers.
Can legally blind people see?
Most can see something. SSA says very few people who meet the definition are totally blind. Some see light and shapes, some read large print, and some, with a narrow visual field, see sharply but only in a small area.
What is the difference between legally blind and visually impaired?
"Legally blind" is a specific legal line: 20/200 or a 20-degree field. "Visually impaired" is a general term that AFB uses for anything from low vision to total blindness. Every legally blind person is visually impaired, but many visually impaired people are not legally blind.
Is tunnel vision legally blind?
It can be. If the visual field of the better eye is 20 degrees or less at its widest, the law treats that eye as if it had 20/200 acuity, even when central vision is sharp. AFB calls a field like this tunnel vision.
Who decides if someone is legally blind?
Each program decides for itself. For the higher standard deduction, the IRS asks someone who isn't totally blind for a certified statement from an ophthalmologist or optometrist. The National Library Service accepts certification from a "competent authority," such as a doctor, an optometrist, a nurse or, if none is available, a librarian.
Is legally blind the same in other countries?
Not necessarily. The 20/200 and 20-degree rule is the US definition, and the World Health Organization uses its own categories for statistics. WHO's "blindness" means acuity worse than 3/60, about 20/400, so many people who are legally blind in the US fall under "severe vision impairment" in WHO figures. Worldwide, WHO says at least 2.2 billion people have a near or distance vision impairment.