A few years ago I had a session with a gun fitter and he told me that when he was taking shooting lessons the coach told him to "focus" and he had no idea what that meant. He began working with major league ball players and was told by the good hitters that when they could see the stitches on the baseball anytime after the ball left the pitchers hand, they could get a good hit and often a home run.
The fitter went on to say that to shooter's "focus" meant being able to see a small area of the bird or target and that area appears to be as big as a softball. He gave me some exercises, one of which is when riding as a passenger in a car, concentrate on the rivets attaching the small roadside reflectors that are present on secondary roads. I practice doing that and after a few days the reflectors were huge and that was all that I could see. I have been able to "focus" the stitching of fast balls thrown by AAA little league kids, the white ring on pheasant and the heads of smaller birds. Small birds are everywhere, try and focus on their heads as they fly by. It's an amazing thing when it all comes together.
Please disregard if I have misunderstood your request for eye exercises.
