Generally, kittens gradually open their eyes between 7 and 14 days after birth. This is a gradual process; initially, it's just a small slit, then it gradually widens. During this process, the kitten's eyes gradually adapt to the light and begin to explore its surroundings. However, there are some exceptions.

Some kittens may not open their eyes until 1 to 2 weeks after birth. This does not mean they have any problems; it is simply an individual difference. Similarly, if a kitten has not opened its eyes by 2 weeks, it is recommended to take it to a veterinarian for a check-up to ensure its eye health.