Vistar Insights

What Does 20/20 Vision Mean?

Tuesday, June 02, 2015

You know it's a good thing when your eye doctor tells you that you have 20/20 vision, but do you know what those numbers mean?

The American Optometric Association defines 20/20 vision as normal vision acuity (the clarity and sharpness of your vision) measured at a distance of 20 feet.

When you go to the eye doctor, your visual acuity is measured with a Snellen Chart, that white poster with the printed letters in descending sizes. Your eye doctor will ask you to read as far down on the chart as possible without squinting or visual aids. If you have 20/20 vision, that means you can clearly see and read the line that a person with "normal" vision can see when they stand 20 feet away from the chart. If you have 20/40 vision, your eyesight is slightly inferior, and you can see at twenty feet what a person with normal vision can see at 40 feet.

Your left and right eyes can have different visual acuity. Eye doctors use comprehensive eye exams to determine the corrective prescription lenses you need to be able to see with 20/20 vision.