The fact that the color of the cat's eye, as, indeed, and the eyes of man, depends on the quantity of coloring pigment in the front and back of the eyeball. And, like most human babies, newborn kittens eyes are gray or blue-gray. If the child's eyes will change color only to 6-8 months, eyes kitten turns green or yellow after a few weeks. All this is because melanin in newborns quite a bit, and then it begins to accumulate in iris.
But in cats things with the eye color is slightly different than in humans. Some breeds eye color sex-linked coat color. For example, Siamese cats eyes, usually blue, and the British amber. The problem is that, unlike coat color, eye color in kittens when breeding is very difficult to manage, and "right" eyes are very much appreciated by fans of the breeds.
What occurs inside the eye when the color starts to change? When the kitten is still at the stage of the embryo, it has about 30 pigment centers. Until the end of embryonic development, pigment cells do migrate throughout the body, spreading through coat and iris of the eye. However, by the time of birth of the kitten the pigment in the coat is already settled permanently, but in the eyes continues to accumulate. The saturation of the blue color of the eyes of a kitten depends on the number of pigment granules in the retina of the eye. All colors except blue, are dominant, and thus, with age, the eyes of kittens can only go from blue to some other, but never in blue, if the eyes are not blue at all.
As among people, among cats, there are albino cats with red eyes (sometimes with only one red eye). Albinos have pigment in the retina is completely absent, so under the retina are clearly visible blood vessels. These cats eye color also will not change ever.
Some scientists believe that the color of eyes had something to do with the diet of cats, however, direct evidence is not.
Whatever it was, the eyes of cats — quite a fascinating spectacle, no matter what shade they had.