When teaching vision, coaches should really focus on training a players peripheral vision. Especially when you are going towards goal. When players at the highest level score goals, their primary focus is the ball. Often times if you were to rewind the game before the goal scorer gets the ball and rewatch the goal, you'll see a player that hardly looks up at all, because they already looked before they got the ball or a few touches before the goal being scored.
I consider myself a soccer teacher. Not a soccer coach. Many coaches will tell a player what to do, when to do it, and where to do it. My focus is to give each of my players the WHY.