Ask Batha again about this now that he and others have been discussing "eye dominance" as well as ability to focus on items in the distance. This is particularly true for women; we probably don't spend enough time honing eye-hand coordination when we are young. Don't really know though.
One way to test this is to keep moving the "target" back from the shooter in the "quick aim" exercise. I am right-handed. I am right eye dominant. Still, at a point not all that far out, I "switch" to using my left eye to acquire the target. My left eye is much stronger than my right eye even with my glasses. The switching is much more evident when I am tired or in bright sunlight.
As far as it has been explained to me, eye dominance is something the brain creates. This means neurological aspects rather than a strength. It is a processing preference if you will and probably hard-wired. For many of us though, the binocular picture is impaired in some way even without blocking one eye or squinting as a target is acquired. It is the moving target in the distance which causes me a problem when shooting a shotgun; I'd be much more right-eyed at a stationary target about the length of a room away.
Focus exercises such as those Chris advocates definitely help.
Vision has many aspects to it as we all know. Like most, as I near my fiftieth year, my eyes are getting less near sighted. In addition, my eyes are not changing at the same pace. I don't seem to use my eyes together in many respects. It seems I tend to read with my right eye. It also seems that I tend to view distant or horizon objects with my left eye. I've been told by several shooting instructors as well as eye doctors of the various types that this is not all that uncommon. (Hence one contact lens prescribed for distance for a while for some.)
It would probably be most correct to say that eye dominance and focus are competing to make target shooting difficult for me.
