They normally open there eyes after a couple or 3 weeks from when they were born. It varies by hamster but typically when they are 15-18 days old. The open eyes of human babies at birth tell us that our brains are quite mature compared to hamsters.
It should take no more than a month for them to open their eyes. All of the Teddy Bear Hamsters I had averaged between 3-4 weeks. One little guy took 5 weeeks to open his eyes.. I think he was just lazy.
It takes couple of weeks to open there eyes. But the case depends upon the type of breed that
you are having. May be it will take more days for your breed.