For me, personally, I always keep them open and I try to stay awake. I am like everyone else, there are times when the mind wanders for a while and if my eyes are closed, I have seen that it will wander more often. So for me, personally, I keep them open so that I can stay awake. There are obviously some people who keep them closed, but from watching everyone in every retreat, when I give the talks, I know that over 90 percent of everyone do keep their eyes open.