Dunmeri eyes are bloodshot, like in previous games.
Altmeri eyes are normal, like they were in previous games.
Woodelves have tiger-like eyes. In theory, pupils expand and eyes look black. On textures pupils are contracted so you can see the texture of the iris.
"Demon" black eyes are now daedra eyes, like they were in Oblivion. Play as daedric prince in disguise instead of boring black eyes.