20/20 vision and the vision chart

You most likely already know that having 20/20 vision is a very good thing, and that this is determined during an eye exam, by reading letters from a vision chart. But you may not know exactly what “20/20” means, or exactly how it’s determined by the letters you read. This post will look at some of the specifics of what this term means, and how vision charts help in determining it.

“20/20” definition

20/20 is considered to be a “normal” level of vision, and is based on what you are able to read from a distance of 20 feet. If you have 20/20 vision, this means that you are able to read letters from 20 feet away that most other people can read from that distance as well. When you look at a vision chart, the 20/20 vision line is typically the 4th row from the bottom; this means that if you are able to read the letters in that row, you have 20/20 vision.

Other vision levels

The 3 rows of letters beneath that 20/20 vision line represent even higher vision levels (20/15, 20/10, and 20/5). If you’ve never been able to read those letters during an eye exam, don’t sweat it; there aren’t many humans out there who can! In fact, many birds of prey, such as eagles, have 20/5 vision or better (you can learn more about that here).

On the other end of the spectrum, if you are unable to read the letters on the 20/20 row on a vision chart, you eyes will most likely need some form of vision correction. Most states in the US require you to have at least 20/40 vision in order to have a driver’s license; for the vast majority of people who don’t already meet this requirement, vision correction such as eyeglasses or contact lenses will more than do the trick.

Reach out to us

I hope this post was informative, and that it helped to educate you a bit on just what 20/20 really means, and how the vision chart you see during eye exams helps to determine it. If you’d like to learn more, or if you’re interested in talking to us about an eye exam, we’d love to hear from you!