Usually they don't open their eyes don't start opening around 2 weeks or so.

 Kittens are able to make a hissing sound even before they open their eyes. They can recognize their mother and humans by the smell, so if they don't recognize the smell of who is near they will sometimes hiss with their mouth opened and even spit—even at one week old.
  
then the eyes open...

Shorthair kittens begin to open their eyes at 5-8 days.

Longhair kittens do not open their eyes until 10-14 days.
 
Isn't that strange? So if some of your kittens don't have their eyes open yet, but the others do, it may be because they are longhaired. All kittens' eyes are beautiful deep orbs of blue at first. They will look like this until the kittens are three weeks old. Then the iris and pupil will form and the kitten's permanent eye colors will slowly emerge. At first, although the eyes are open, the kittens are still almost completely blind.
 
Information retrieved from link - KITTEN DEVELOPMENT!
 
I hope that answers your question.