Why do you need to close your eyes to sleep?

Question

do the eye lids do something

Answer 1

dry out !!

Answer 2

We need to close our eyes to sleep because the eyes would dry out otherwise, it provides a layer of protection against dryness and foreign bodies.

Answer 3

I've known people who would occasionally fall asleep with their eyes open.  My grandma used to do it all the time when I was a child and it would creep me out.

I know I can't do it and would not want to because it dries out your eyes.

Answer 4

It's pretty much involuntary. Try to sleep with your eyes open.