Vision is the ability to see potential passes.
For example, a player with mediocre passing ability only sees what’s directly in front of him. He passes the ball to a forward with a defender on his back.
A player with good vision will quickly scan the field and find a better pass. He sees the forward is marked tightly, looks right, sees the right winger can’t shake his man, then looks left. He sees a hole in the defense. He passes the ball through the hole into space and the left winger runs to the ball.