The sports of badminton or pingpong is a activity with high speed. When you play badminton or pingpong, your eyes should follow the ball. Then your eye muscles can be strengthened to promote the blood circulation. So if you do long-term sports of badminton or pingpong, it will improve your vision to some degree.
It is possibly that your vision will get imroved by playing badminton or pingpong.Because the eyes need to see far and near alternatively and move around fast to enable you to see the objects.Then the eye muscles contract and relax frequently to promote the blood circulation in your eyes.
Your vision acuity may get improved by this way.