The bottom number reflects the smallest letter size you can read. For example ... The term "20/20 vision" refers to how sharp your eyes are when you look at an eye chart from a distance of 20 feet. It ...

a chart with the letter 'E' in different directions (up, down, right and left) and sizes. This E chart visual acuity or eye vision test is very easy and is very useful in testing the eye sight of kids ...