Fred wrote "There was a time in Russian literature when a beautiful heroine's eyes were always black. If you wrote something else you were apparently not a very good writer. I don't know if most Russians then much preferred black eyes, but some probably came around, on at least some superficial level, to sort of go along with it as a general preference. Maybe it was nice to be seen courting a black-eyed girl. "

There is exactly the same cultural preference in Glasgow. Except normally the woman has only one black eye.

Murray