You may have recently brought home an adorable new kitten with baby-blue eyes. But did you know that those icy-blue eyes might change to green, brown, or even hazel? Most kitten’s eyes will change color as they age. This will happen when your kitten is seven weeks old.
So, when exactly can you expect your cat’s eyes to change colors and why does this happen? Here’s everything you need to know.
Why Do Kittens Have Blue Eyes?
All kittens are born with blue eyes. While some breeds, like Siamese cats, will retain this eye color throughout their entire life, most cat eye colors will change over time. A kitten’s blue eyes are caused by refracted light. What we perceive to be blue-hued eyes is actually a lack of color combined with refracted light. Cat-eye color is largely produced by iris pigmentation and the degree of transparency along the outer edge of the eye.
Kittens are born with their eyes shut. When they are between seven and 14 days old, their eyelids will begin to separate and open. During the first month of her life, a kitten will only see light blurs of shadows and colors. Between five and seven weeks of age, the kitten will achieve full visual and ocular functionality.
During the developmental eye period when a kitten is learning how to see, her eyes won’t be fully mature. It’s a vision first, color second situation for cats. After the eyes open, the kitten’s eyes will be blue. As her seeing matures, the color of her eyes will slowly transform.
When the kitten is six or seven weeks old, her eyes will assume their adult eye colors. This is because the melanocytes of the eye will be fully mature. The melanocytes produce melanin, the pigments which determine eye color. How many melanocytes there are and how much melanin they produce will determine the final color, intensity, and depth of the cat’s eyes. Light green cat eyes have small amounts of melanin while brown eyes have the most melanin.

Why Do Some Adult Cats Still Have Blue Eyes?

Certain cat breeds will retain their blue eyes through adulthood. These breeds include:
Their blue eyes are the result of partial albinism. These cat breeds have limited amounts of melanin, resulting in a unique blue color.
- Complete heterochromia: This occurs when a cat has one blue eye and one brown or green eye.
- Sectoral heterochromia: This is when a cat has two distinct colors in the iris.
- Central heterochromia: The cat has different colors in the iris and along the outer portions of the eye.
Will My Cat’s Eye Change Colors as She Grows Older?
Once a kitten reaches seven weeks of age and has gotten her adult eye color, her eyes will not turn colors again. However, a cat suffering from cataracts might appear to have shifting eye colors.

Conclusion
Your kitten’s eye color will most likely change if she isn’t one of the aforementioned breeds. However, all cat eye colors are beautiful and won’t subtract from how special your kitty is.
Featured Image Credit By: Anna Azarenko, Shutterstock