Putting mirrors, like the kind you see Young using in this footage, are a popular choice among tour players because they help them check to see where their eyes are in relation to the golf ball.
-The conventional wisdom is that your eyes should be directly over the golf ball, but most teachers will tell you that really it depends on where you’re most comfortable. A little inside the ball can be ideal for some golfers; it all depends on how best you see the line of the putt.
- Another key thing that putting mirrors help check is alignment. While you’re checking to see if your eyes are over the ball, you can also make sure that your head isn’t tilted in an awkward way, or that your shoulders are pointing off in another direction. Pros, for the most part, use the mirror to make sure things are running parallel to the target line. He's very high percentage of tour players have putting mirrors in their bags.
Cameron Smith:
"I use a putting mirror before every round.
The mirror enables me to make sure my body is in the correct position before I even take the putterhead back. My shoulders are square and my eyes are directly over the ball.
If either of those things are even slightly out, it affects the way the putter moves through the ball."