Our eye color comes from the iris, that colored ring around the pupil which filters light into the eye. The color of our eye is determined by the presence of a protein called melanin which also determines hair and skin color.
Almost all babies are born with brown eyes, even if they don’t stay that way forever. Eventually before the end of infancy, our eye colors mature into what they will naturally be whether that is blue, green, brown, hazel, green, or even gray!
However, there are some cases where eye color can change later in life. It all sounds very sci-fi and strange, but it does happen. In fact, nowadays it’s not uncommon for people to change their eye color either through cosmetic surgery or with colored contacts. When it happens naturally, there’s usually a perfectly good scientific explanation for it, and it’s often a result of an underlying health or medical issue.
So without further ado, here are all the health-related reasons someone’s eye color might change…
1. Newborn Eye Color
While this isn’t necessarily a health condition, it’s a big eye color change and as promised, there’s a scientific reason to explain it. As we previously mentioned, most babies are born with the same brown eye color and that is because the melanin, which is responsible for determining eye color, comes from special cells called melanocytes. These melanocyte cells create melanin when needed and will respond to light (hence why our skin becomes darker when it’s exposed to the sun). “The melanocytes in the eyes of newborns have never been exposed to light, so they haven’t become fully active,” writes Healthline.
It doesn’t matter what their race, gender, or skin color is, all babies are all born with brown eyes. (However, some Caucasian babies can be born with blue or gray eyes). “As melanocytes are activated by light over an infant’s first year of life, eye color may change. Typically, this means turning from a blue/gray (low melanin) to hazel/green (medium melanin), or to brown (high melanin).”