There is a very simple cure for this problem, which Young doctors don't experience yet, till they get older and are a senior, or on a diet and can't sleep.
It comes down to this. THIN EYELIDS, why this is when you get older your skin thins, also if you are on a long diet you lose fat all over your body,and including the eyelids. To check this out, just put your hands over your eyelids, and see if they block out more light. To solve this make sure your bedroom is very dark, and if not buy a good SLEEP MASK and if your room is noisy, get ear plugs, also what is good, eat a big sandwich, as when you do this your blood leaves the brain and goes to the stomach to digest the food. Simple physics. I know it works, because I am 76, and sleep like a baby. When you have to go to a Hospital, take ear plugs and a mask with you, and you will sleep. To bad the medical profession can't figure this out, but then again most of them are not seniors. Have a goodnite.