Why does my dog sleep with her eyes open?

Haha just wondering why my dog, a chocolate lab/ german shepard mix always sleeps with her eyes open. Its like whenever you look at her asleep, her eyes are way up in her head but her eyelids are still open...its kinda freaky lol.

I have no idea why dogs do this but my dog does it too. Nothing to worry about though, just like when some humans sleep with their eyes open. I know that on some breeds of dogs like mine, they have a layer of skin between their eyeball and eyelid that comes up and half way over their eyeball when they sleep so they dont have to close their eyes. its usually in breeds of dogs that are bred to hunt because the piece of skin acts as a camoflauge over the white in their eyes when they are hunting, ive never seen it during hunting but when my dog sleeps it comes up a little over his eye likie a centimeter and his eye goes in the back ofhis head and his lids are open lol looks really ugly and freaky

either what Lauren Alyce(think thts right soz if not) said or because i heard somewhere that they sleep like that to watch out for predators but thats either dolphins or dogs my dog sleeps with one eye open but only tiny open like when you first wake up at 7am after goin bed at 11pm thats horrible u shud get up wateva time u went bed