Todd: "In the beginning there were two images. Concentration allows you to see one."
I was under the impression that one wanted the two images - each eye focused on a different object at a different distance.
At what distance do you most commonly shoot? That may make a bit of difference. The closest targets that I practice on are 50 ft., 25yds is more common, and the Bullseye long line is at 50yds, as is the International Free Pistol target.
Despite my willingness to try, I remain skeptical. You pretty obviously have excellent eyesight (can see the perforations on a IPSC target at seven yards); that gift would make the "switch" from eye to eye (which I still feel is far more probable - with all due respect) almost completely seamless, giving the strong impression that the images were being seen simultaneously as opposed to sequentially.
In any case - more info about the one or two image thing would be helpful.