20/20 Vision: What Does It Mean?

The term is used all the time, but what exactly does it mean? 20/20 vision is a term relating to the way visual acuity is determined. Visual acuity refers to the clearness of your vision. This number is determined sometime during a routine eye exam, by use of a Snellen chart (one with rows of different letters of varying sizes) or a "tumbling E chart" (with E's facing in various directions and sizes).