Actually, every now and then, especially when I'm nervous, my focus will narrow like this. It's very strange for me when it happens. It's as though my peripheral vision ends at the rails and the entire world is the color of Simonis green. Mind you, I am actually incredibly accurate when this happens. However, it really bothers me and is my signal to take a break. I mean, this may happen like a couple times a year but when it does, you'll see me get up from a very routine shot and take a 2 minute break.