What does legally blind mean?
Quick Answer
In the United States, "legally blind" means your best-corrected vision in your better eye is 20/200 or worse, or your field of vision is 20 degrees or less. It is a legal and administrative definition used for benefits and services, not a description of seeing nothing. Most people who are legally blind still have some usable vision.
Key Takeaways
- US definition: 20/200 or worse in the better eye with glasses or contacts, or a visual field of 20 degrees or less
- 20/200 means you see at 20 feet what a typical eye sees at 200 feet
- Measured with the best possible correction, so poor uncorrected eyesight alone does not count
- Most legally blind people are not totally blind
- Other countries use different terms and thresholds (for example "severely sight impaired" in the UK)
- The status matters for disability benefits, tax provisions, driving and services
The US Definition of Legal Blindness
The definition used by the US Social Security Administration (SSA) and many state agencies has two alternative parts. A person is legally blind if, with the best possible correction in the better eye:
- central visual acuity is 20/200 or worse, or
- the widest diameter of the visual field is 20 degrees or less (severe "tunnel vision").
A normal visual field spans roughly 180 degrees horizontally for both eyes together, so a field of 20 degrees is a very narrow window.
What 20/200 Vision Means
Visual acuity is written as a fraction. The top number is the testing distance (20 feet); the bottom number is the distance at which a person with typical vision could read the same line. With 20/200 vision, the big "E" at the top of a standard eye chart is often the only letter you can read.
| Acuity (US) | Metric equivalent | What it usually means |
|---|---|---|
| 20/20 | 6/6 | Typical vision |
| 20/40 | 6/12 | Meets the vision standard for a driver's license in most US states |
| 20/70 to 20/160 | 6/21 to 6/48 | Moderate low vision |
| 20/200 or worse | 6/60 or worse | Legally blind in the US (in the better eye, corrected) |
What Can Legally Blind People See?
Quite a lot varies from person to person. Depending on the cause, someone who is legally blind may:
- see large shapes, colors and movement but not faces or print (common with macular degeneration, which damages central vision)
- see sharply straight ahead but nothing to the sides (common with advanced glaucoma or retinitis pigmentosa)
- see everything as very blurry or washed out (for example with corneal disease or cataracts that cannot be treated)
- perceive only light and dark
Only a minority of people who are blind have no light perception at all. See what blind people see for more on the range of experiences.
Legal Blindness Outside the US
Thresholds and names differ by country:
- WHO / ICD-11: "blindness" is presenting acuity worse than 3/60 (about 20/400) in the better eye; worse than 6/60 is "severe" visual impairment
- United Kingdom: people are certified as "sight impaired" (partially sighted) or "severely sight impaired" (blind) by a consultant ophthalmologist, based on acuity and field together
- Canada: generally the same 20/200 or 20-degree rule as the US
- Australia: legal blindness for benefits is usually acuity worse than 6/60 or a visual field of 10 degrees or less
Why the Legal Definition Matters
- Benefits: in the US, "statutory blindness" can qualify a person for Social Security Disability Insurance or SSI under special rules
- Taxes: US taxpayers who are legally blind can claim an additional standard deduction
- Driving: legally blind people do not meet standard driver's license vision requirements
- Services: access to orientation and mobility training, talking books, white-cane and guide-dog programs
Frequently Asked Questions
Can a legally blind person see?
Usually, yes. Legal blindness is a threshold (20/200 or a 20-degree field), and most people who meet it still have some vision, such as light perception, shapes or a narrow field of clear sight.
Is 20/200 legally blind with glasses?
Only if 20/200 is the best you can see with glasses or contacts in your better eye. If correction brings you to 20/40, you are not legally blind even if your uncorrected vision is 20/400.
Can legally blind people drive?
Generally not. Legal blindness does not meet standard licensing requirements. Some US states allow restricted driving with bioptic telescopic glasses for certain people with low vision, under strict rules that vary by state.
What is the difference between legally blind and totally blind?
Totally blind means no light perception at all. Legally blind is a broader category that includes people with significant but partial vision.
Is legally blind the same as low vision?
Not exactly. "Low vision" usually means vision that cannot be fully corrected and limits daily tasks, often starting around 20/70. Legal blindness is the more severe end of that range.