As an ability attribute, vision determines a footballer's awareness about his teammates' positioning, for passing the ball to them and performing the tactical strategies on the field.
A player with a good vision will be able to recognise which player is the best to pass the pass to. Usually, players with a high vision rate are considered smart and can initiate moves that finish up with scoring goals.
Midfielders are required to have a high rated vision as they are supposed to feed their attackers and create chances.
Improving your peripheral awareness will help you to have a better vision. Playing with your head up will also help you to do so, which requires you to have good ball control, dribbling skills & reactions.
Footballizer Vision training game which is a bubble shooter, will also help you to improve your vision in a simple way. This game enhances your awareness by letting you to recognise matched colours and acting quickly.