The first twenty in the term “20/20” is how many feet you are from the eye chart. In most eye doctor offices that eye chart is 20 feet away from you. The second twenty is the size of the lettering. So 20/20 means that the average (see, there’s that word again) person should be able to see a 20-size letter from 20 feet away. What if you have horrible vision – 20/200? That means that the letter your able to barely make out sitting in the exam chair has to be 10 times (200 is 10 times larger than the 20-size letter) larger for you to tell what letter it is (see figure 1).
I‘m about to tell you something few eye doctors would ever reveal – 20/20 vision is not great vision. It’s actually average vision, nothing more. Let’s review what 20/20 means.