Some of my rex kittens were opening their eyes at 5 days old. It varies from kitten to kitten, but all should have their eyes open by about 14 days old.
My kitten Garfield, from last year's litter, eyes opened at 3 days. Actually her right eye was the only one open. Hey I am curious, if one of the kitten's eyes are open at 3 to 5 days, can they see? Penguine's eyes opened at 6 days.