Eye Color Change in Infants

Melanin's Work in the Eyes

• Melanin is the pigment that gives color to skin, hair and eyes, and cells called melanocytes produce this. The amount of melanin in the top layer of the iris (the area surrounding the pupil) determines the eye's shade. Just as on the skin, melanin in the eye is affected by light. When a baby is first born, the shock of light on the eyes kick-starts melanin production in that organ. The pigment will build and interact with other factors during the first years to determine eye color.

Eye Color and Ethnicity

• Not all babies are born with "baby blues." Caucasian babies almost always are--usually a dark blue or a slate-gray, according to the What to Expect website. Babies with dominant Asian, Hispanic or African heritage, however, typically arrive in this world with brown or black eyes that stay dark, although they may become darker over the years.

Melanin Levels and Color

• The presence of a little melanin produces blue eyes, which explains why most Caucasian babies are born with eyes in shades of this color; newborn eyes haven't had enough time in the light to build up greater stores of the pigment. A little more melanin produces green, gray or hazel eyes, and greater amounts produce brown of black eyes. No melanin produces the rare condition, albinism, in which the eyes appear red. Infants of ethnicities other than Caucasian are naturally born with greater amounts of pigment. Sometimes color from the back of the iris will shift to the front, producing a darker ring around a paler iris.

Stages of Development

• An infant's eye color slowly changes over the first year, with the final color usually set by 3 years. Ten percent of people, however, continue to experience changes well into adulthood, according to the What to Expect website. The most dramatic shifts in shade will usually occur between 6 and 9 months, and while colors may change or darken, they will not lighten, as melanin builds ups in the iris.

The Role of Genes

• The role genes play in eye color development is not entirely clear, the What to Expect website states. While it is clear genes do play a pivotal role, eye color is determined by a number of genes and other environmental factors interacting, not all of which are understood. Experts can estimate probabilities, but that's about it. For instance, brown tends to dominate blue, but not entirely so; if one parent has blue eyes and one parent has brown, the child had a 50 percent chance of getting either color. If both parents have brown eyes, but at least one grandparent has blue eyes, the child may end up with blue, not brown. Two blue-eyed parents will probably produce a blue-eyed child, but this is not true 100 percent of the time.