>> According to these articles until sometime after 17th 

>> century man did not sleep 8 hours straight through.



I've often wondered about the whole "lights out" theory. It always seemed to me that during the paleolithic it would have been very dangerous to sleep the entire night through. Someone would have to be awake and alert, and taking turns at it would be natural. Perhaps that's where the "bi-modal" sleep habit started?



A friend who spent spent 20+ years in the army told me they did quite well with "power naps". In fact, it was encouraged.



>> I may be grasping at straws but I was wondering if the 

>> change in our sleep pattern has had a negative effect on our vision.



Intriguing. I would love to figure out a way to throw out my reading glasses.