Kittens are born with their eyes closed, but around 8-12 days after birth, their eyes will slowly begin to open. At this stage, all kittens will have baby blue eyes, which will change to their adult eye color as they age. The iris, the colored part of the eye, contains melanocytes, and once the eye is sufficiently mature, these melanocytes begin producing melanin, which gives the eye its mature adult coloration. Kittens eyes change color when theyre about 4-8 weeks old. By week 6 or 7, a kittens eye color begins to change, and the adult eye color will begin to emerge. Kittens with grey, green, or yellow eyes are likely 7 weeks or older. However, some kitties, depending on breed, retain their baby blues. Most kittens eyes will have changed color by 3 months old, but some kittens dont develop their permanent eye color until around their first birthday.