Why Can’t We Sleep With Our Eyes Open?
We cannot sleep with our eyes open, because to be asleep involves losing control of most of the functions of the body. When we sleep the brain sleeps also. Perhaps it would be stated more clearly to say that we cannot sleep while the part of the brain which controls our activities is awake. There is a part of the brain which has the power to open our eyes, i. e., lift the eyelids, and when that portion of the brain ceases to exercise its power to keep the eyes open, they go shut. Even when we are awake that part of our brain cannot keep our eyes from winking, because there is another part of the brain which sees to it that our eyes wink every so often. This is done for the purpose of washing the eye-ball, and is the answer to another of your questions which is given in another place in this book. When the engineer at the electric light plant shuts off the power all the lights go out, and when you go to sleep you automatically shut off the power that opens your eyes, and the eyes are shut. The brain is asleep also, and if it is not completely asleep, you are restless.