"It is extremely difficult to knock someone out with elbows to the back of the head. And it sure doesn't cause blindness."
Are you kidding me? back of the head = bass of the skull where the skull meets the vertabrae. Ive been woozied up from a forearm to this spot, and it wasnt a very hard one either... and Ive got no glass jaw, mind you. Ill dig up some medical research proving trauma to this spot can cause blindness as well, just check back on this thread in a day or two.