Why do kittens have blue eyes?
Kittens are born with blue eyes because the melanin, which gives colour to the iris, is not present at birth. Once the eyelids open and the eyes are exposed to light, melanin production increases, causing their eye colour to darken. The final eye colour may not be determined until 6 to 18 months after birth. This is similar to skin darkening from sun exposure. Skin darkens in the sun due to the production of melanin, a pigment that provides protection from the harmful effects of ultraviolet rays. When skin is exposed to the sun, melanocytes increase the production of melanin to protect the skin, resulting in a tanned appearance.
A kitten’s eyes are closed at birth because they are developing and need time to grow and mature, which helps protect the eyes from environmental light. The eyelids remain closed until 7 – 10 days after birth. Once the eyes open, they are a pale blue in colour. Some kittens will maintain their blue eyes for life, while the eye colour of other kittens will gradually change from blue to yellow, copper or green.