That would be a pretty neat trick.
However, humans do not have the ability to use each eye independently of each other. Neither do we have the ability (pretty sure no ones ever done it) to focus each eye independently of each other. So, using "an eye to look through the sights and the other eye looks at the target" is a bit misleading. I feel like folks are going to be on the range giving themselves headaches trying to accomplish this.
Been doing it for about 25 years. It's called indirect sighting. The eyes do not have to have visual focus on the sights to "look through" them with attention focus on the sights. They may appear slightly fuzzy, but you certainly can see them, align them, and be aware of them while "mechanical focus" of the eyes is on the target. It sounds more complicated than it is, I started doing it and found it wasy but then I was unaware how difficult it was supposed to be to do it.