Small things can make a BIG difference when you work.
Take for example a simple thing like your hat on game day. Wearing your hat, slightly raised on your head, can actually bring distractions to your attention that you would other wise not notice.
Simple things like a batter in the on deck circle, trash blowing around home plate, and other things can break your concentration just when you need it the most.
Snug you cap down, so the bill of your cap is about two finger widths from the bridge of your nose - at the forehead, is a good fit.
Basically, what you’re doing is minimizing the view of your peripheral vision and solely concentrating on the target 60’ (approx) away.