Here are 3 exercises how you can train your eye performance and brain:
Juggle while you read projected numbers on the wall in the background (juggling per se is already a good brain integration exercise).
Put a string on the floor and place numbers in three differently colored cards (e.g. blue, yellow, red) left and right of the string. Now hop from one end of the string to the other. If you have a yellow card, you can only jump on your left leg, when there’s a red card you can only jump on your right leg. When there’s a blue card, hop on both legs. If the exercise is too easy, you can add the numbers on the colored cards as you hops.
Put your arm out with one thumb up in front of your face and the other arm with your thumbs up behind it. Then first fix the front thumb and concentrate on how the thumb behind it can suddenly be seen twice. Then switch with your attention to the thumb behind it and watch what happens with your front thumb!