They say that eyes are the windows to the soul. So what causes them to be certain colors and pigments? There are a multitude of physical traits and aspects which cause eyes to choose their physical appearance. Baby eyes derive their appearance from the combined genetics of their parents, but so many things go on during the genetic makeup of a baby that eye pigment is unpredicted until birth.
Eye pigmentation and color is determined within the iris. There are three well known and understood genes of eye pigment, which are brown, blue, and green. These colors are very common around most people. Rarer colors, such as hazel, are difficult to understand and attribute an explanation for.
Many people think that a baby’s eye pigment is either one of their parent’s eye pigments, or the combination of both parents’ eye pigments. In actuality, this is untrue; there are two pairs of genes found within each chromosome, so many possibilities of different eye pigments exist. However, if both parents have the same colored eyes, it’s predicted that their baby will most likely share that same pigment.
Most babies are born with blue eyes. As they mature, their eye pigment can change within their first three years of life. This is very true with babies that have brown eyes. This is due to the fact that brown eyes are pigmented by a chemical called melanin, which only develops with age.
In some cases, babies are born with irises of two different colors. This can be caused by multiple aspects, including trauma that occurred within the womb or birthing process, malfunctioning pigment development, inflammation, or a genetic disorder.
General changes in eye pigment occur for a number of different reasons. One change of eye pigment is due to the dilation of the pupil. The iris, which is actually a muscle, expands when controlling the size of your pupil. As the pupil increases or decreases in size, eye pigment will be subtly affected.