20/20 vision describes the sharpness of your distance sight on a standard eye chart. It means you can see at twenty feet what a person with normal eyesight should see at that distance.
How 20/20 relates to clarity
The first number is the testing distance. The second number shows the smallest line you can read compared with a standard observer.
- 20/20 does not mean perfect vision, just normal distance sharpness.
- 20/40 means you must be at twenty feet to see what others see at forty.
- Some people see better than average, for example 20/16.
- Short-sightedness, long-sightedness, and astigmatism can all reduce acuity.
- Glasses, contact lenses, or surgery can correct many refractive errors.
Limits of the 20/20 measure
Good eye health involves more than an acuity score. Comfort, depth perception, colour vision, and visual fields all affect daily life.
- You may have 20/20 vision yet still struggle with glare or night driving.
- Dry eye or cataract can cause fluctuating clarity despite normal test results.
- Regular eye exams check both acuity and internal health.
- Different countries use similar but metric scales, such as 6/6.
- Tell your clinician about any symptoms, even if the chart looks fine.
