To share what little I know about eye dominance...most right handed people are right eye dominant and most lefties are left eye dominant. There are widely varying degrees of dominance; some people have a strongly dominant eye while others have one eye which is barely so. To make things even more complicated, there is evidence that as we age, our dominant eye becomes less so, and in some cases control may even shift to the previously non-dominant eye.
Then there are the exceptions to the rule, cross dominant people like DD (insert obligatory snide remark correlating cross dominance with cross dressing here :grin

And yes, there are those who exhibit no real dominance as mentioned above. When fitting shotgun stocks, we referred to this as central vision. The point has already been made that if a shooter is cross dominant and shoots with both eyes open, he will miss the mark by a greater or lesser distance, depending on the range. In this situation, the sufferer must either learn to shoot with the non dominant hand, force the non dominant eye to take over by using tape or Vaseline on the dominant eye lens of the shooting glasses, or by simply closing one eye.
There are some very real advantages to shooting with both eyes open. It increase our peripheral vision substantially, and without binocular vision we have no depth perception, which is necessary to estimate range.
I won't presume to address the tactical pros and cons of closing one eye when in a tactical situation (overused phrase, I know, but it seems to fit here). Tom Givens devotes a section to it in "Fighting Smarter" that makes some interesting points and is weelworth reading. Tom is one of the moderators here; perhaps he will comment.
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David
<font size=-1>[ This Message was edited by: David Cosby on 2001-05-20 17:02 ]</font>