Did you know that most babies are born with blue eyes? However, given that in the world only 8% of people have blue eyes, it is evident that, in most cases, that color disappears with time. For what is this?
Melanin is the culprit
There is a belief that babies keep blue eyes due to feeding on breast milk and that the color changes when they switch to a solid diet. However, this is a myth that has no scientific basis and is probably due to the change in color of babies’ eyes coinciding with the end of breastfeeding.
Actually, the color of babies’ eyes depends on the amount of melanin. It is a pigment that is also found in skin and hair. The more melanin we have, the darker our skin, eyes and hair will be.
When babies are born, they have very little melanin, it increases over time. In fact, the final color of the eyes is not known until two years of age since the accumulation of melanin is a progressive process, although some babies reach the final color of the eyes at six months.
If the melanin deposit in the iris is still small, the eyes will be blue, a larger amount turns them green or hazel-colored and if the melanin concentration is greater they will be brown or black. This phenomenon is more evident in Caucasian babies because they have less melanin, while in babies of parents with darker skin, the eyes are usually hazelnut or brown because from birth they already have higher concentrations of melanin. Children with albinism do not have melanin in their irises, so their eyes may appear pink because the blood vessels at the back reflect light.
In fact, people are not the only ones who experience changes in eye color. Kittens, for example, are also often born with blue eyes. However, in these animals the color change is more dramatic because they develop much faster than humans. As if that were not enough, the color of your eyes can continue to change even in adulthood, although it usually stabilizes after a couple of years.
Eye color can continue to vary throughout life
Melanin is a protein, so, like all other proteins, it is encoded in our genes. However, some people may experience changes in eye color throughout life and there are those who may have bicolor eyes.
In some people, the color of the eyes changes again between 15 or 20 years, especially if they are exposed to the sun for a long time since there is a higher concentration of melanin, which forms a thin brown layer around the pupil.
You can also see changes in the color of the eyes according to the seasons of the year. To understand this phenomenon, scientists have studied the changes in reindeer eye color during winter.
They discovered that this change has a specific function: to allow them to see better in the dark. Light is reflected through the retina, and that is why during the summer their eyes appear brown or gold but in winter they take on a blue color.
In practice, the collagen fibers found in the eye change their spacing during the winter so that the pupil stays more dilated and can capture as much light as possible. At the same time, the layer of tissue behind the retina becomes less reflective, which gives it that blue hue. As a result, the reindeer develop a kind of “night vision”.
