I found the frame to be like a electronic gun sight with a large MOA.
Since my billiard eyewear was not a progressive lens, I never looked
or aimed at object balls other than through the middle of the lenses.
I don’t have any limitations in bending or lifting my head or neck while
assuming my pool stance which is lower than most players. I get down
very low and do not get out of my stance with my bridge hand on the
table until the cue ball reaches its final destination on the pool table.
It is the same principle when I shoot trap, long range with my 7mm, or
any of my handguns. I view everything through the center of my eyewear
by positioning my head taking aim. I seldom even look thru the top or
bottom of my eyewear and frankly, can’t recall ever using that type aiming.
As long as the eyewear presents a clear image, viewing through the center
of the lenses offers the best image I can imagine with ample perimeter clarity
of the OB, CB and pool table. Whatever works for a player is all that’s needed.