A Nerd’s Answer to the Question, “What is 20/20 Vision?”

You often hear the term “20/20” when describing “perfect” vision but we thought it might be interesting to dig a little deeper and learn the history of the term and some of the scientific thinking behind its evolution. Basically it has always been explained as a person standing 20 feet away from the eye chart (or magnified to appear that way from the eye-exam chair in case the room isn’t big enough to actually be 20 feet away) being able to read the line of the letter size which a person with “normal” vision can read, when standing 20 feet away.

Snellen chartBut, what is “normal” vision? Doe it come from the statistics term “norm,” as in the norm?

Share This to:
READ:   Ocular Allergies - Causes and Tips for Relief!!