Not knowing if your eyes are open or closed is very strange. I experienced that once while splunking. We sat in a cavern for a while with all of our flashlight

Not knowing if your eyes are open or closed is very strange. I experienced that once while splunking. We sat in a cavern for a while with all of our flashlights off. At first you expect your eyes to start adjusting, then you realize that they aren't going to and you start to think that they're closed. After a while you quit caring what state they're in as it doesn't do any good. It's a very peaceful, almost serene feeling to (temporarily) have the information feed from major sensory organs cut off like that.