Actually, I don't know if it is a dominant eye thing. I just know that when piecing things, I sit directly in front of the needle. It could be that I am off to one side, but I can't tell. But when I shifted from one side of the needle to the other with my piecing, I got that 1/4 inch seam I had not been able to achieve before.
The more I think of it, it probably is just bad body positioning on my part.