What Does 20/20 Vision Mean?

Everyone wants to have the best vision possible. Us surgeons also want to provide the best vision possible. Many people think of 20/20 as perfect vision. Let’s take a look at what this actually means.

It’s actually pretty simple to understand what 20/20 means. Vision is measured on an eye chart with the best correction for the eyes (be it with glasses or not). This allows for someone with glasses to be compared to someone without glasses. On the eye chart are various lines corresponding to 20/20 vision, 20/30 vision, 20/40 vision, etc. If you are sitting 20 feet away from the eye chart (or closer with a properly calibrated chart) and can read the 20/20 line, you have 20/20 vision. If you have 20/20 vision, what you can read at 20 feet is the same as what an average person can read at 20 feet. 20/20 is a measure of the average vision of the population. If you have 20/40 vision, what you can only read at 20 feet is what the average person can read sitting 40 feet out. And conversely, if you have 20/15 vision, you have awesome vision since what you can read at 20 feet is what an average person would need to be 15 feet away to see.

There are a few things to know about 20/20 vision. First is that measuring 20/20 on an eye chart only describes one aspect of vision (how sharp you can read letters or visual acuity). There are other important factors aside visual acuity from that contribute to how well you see. Lastly is that not everyone can reach 20/20 vision. As 20/20 is an average of the population, some people just don’t develop 20/20 vision and some people develop vision better than 20/20! So in refractive surgery, we aim for the best vision possible, which for most people still happens to be 20/20 or better.

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