That's odd. I would never take a shot while hunting, with one eye closed. With both eyes open, the amount of light is greater, the field of view is much larger and your depth perception is far greater. To shoot with one eye closed, while hunting, is a huge handicap in my opinion. All of my hunting buddies shoot with both eyes open. Of course, many of us learned on traditional bows, where almost everyone kept both eyes open and shot instinctively.

Those who hunt with a peep are especially benefited by keeping both eyes open. Peeps cut down on light and obsure your target to the point where you will have some shots that you can't make with a peep and one eye closed.