Static Visual Acuity

This is the ability to see clearly a non-moving object, like the chart at the eye doctor's office.  It is little relevance to real life sports vision needs.

Dynamic Visual Acuity

This is the single most important skill an athlete needs to have the competitive edge.  Hitting a baseball is the most difficult feat in sports.  A pitch comes at eighty to one hundred miles per hour. If it is thrown at 80 MPH, it will take 4/10 of a second for the ball to reach home plate.  It takes 2/10 of a second to just swing the bat, which leaves the batter less than that amount of time to decide whether to swing at the ball.  Ted Williams said that he could see the spin on the ball from the time it left the pitchers hand: only great dynamic acuity would allow him to do that.