Many, but not all, Caucasian infants are born with blue eyes. However, eye color often changes with age; only about one in five or six adults have blue eyes.
Eye color is dependent on the amount of melanin present in the iris. Most humans possess melanin in the back of the iris - the epithelium. The front part of the iris, or stroma, contains variable levels of melanin. Light-colored eyes possess very little melanin in the stroma. So, while the darker epithelium absorbs some wavelengths of light the shorter, bluer wavelengths reflect black, causing the eye to appear blue. This process is very similar to the phenomenon that causes the sky to appear blue. For a newborn child the pigment-producing cells in the eye are not yet fully functional and are not so until around nine months to a year of age. For some people, these cells are not fully operational until the age of three. This means that the child's eyes appear blue at birth but become darker later into childhood.
Viewing an infant's eye from the side rather than from the front can reveal the presence of low levels of melanin. If the baby's eye appears blue from the side it is likely to remain blue. If the eye has a slight gold or hazel appearance from the side, it may darken in the following year.