Depends on the kiss. Passionate tonsil-hockey, eyes closed. Cheeks, forehead, eyelids, bellybutton - eyes open. With an Australian kiss, eyes open so I can see where I'm going, until I get there. An Australian kiss is just like a French kiss, but down under.
Kissing sensation is more intense with my eyes closed but I might crack an eyelid open to see WHO I am kissing; especially to make sure it is not just the dog licking my face to wake my up from napping.