I closed one eye when I shot with a peep. On my old bow I found a real nice light gathering peep.

I now keep both eyes opened but I changed to a Red Dot Scope. It allows for a faster set up and shooting time. It also is said to help people who wear glasses and/or if their eye sight is fading. Knock on wood I still see very well. With that said in the beginning hunts after the change, I still slipped back to one eye closed during the moment of truth. It would throw off my shot. It took a lot of thought to break me of it. I think I have but I always remind myself from the moment I get into my stand. Both eyes need to be open on every shot.

Good luck.