What makes our eyelids shut when we go to sleep?

Question

Is it something in the brain that tells the eyelids to shut? Is it muscle related? What about the odd few who sleep with their eyes open?

In: 0

Answer 1

Eyelids default position is shut, when all face muscles are relaxed. We actually force them to open all the time, unlike some animals (domestic cats iirc have to hold them closed when they sleep).