At birth, most babies have blue-gray eyes. But this color is not final. It will take several months to know for sure if they will finally have the eyes of their dad, their mom, or even one of their grandparents.

The optical apparatus of the fetus begins to form from the 22nd day after conception. During the 2nd month of pregnancy, her eyelids appear, which will remain sealed until the 7th month of pregnancy. His eyeballs then begin to move very slowly and seem only sensitive to differences in light.

Because it is little used, sight is the least developed sense in the fetus: its visual system is the last to be put in place, well after the auditory, olfactory or tactile system. Either way, baby’s eyes are ready to go from birth. Even if it will take them several more months before seeing like an adult.

At birth, most children have blue gray eyes because the colored pigments on the surface of their iris are not yet activated. It is therefore the deeper layer of their iris, naturally blue gray, which is visible in transparency. Babies of African and Asian origin, on the other hand, have dark brown eyes from birth.

Over the first few weeks, the pigment cells present on the surface of the iris will gradually express themselves and color it, until they give it its final color. Depending on the concentration of melanin, the same that determines the color of his skin and hair, baby’s eyes will be blue or brown, more or less light or dark. Gray and green eyes, less common, are considered shades of these two colors.

The concentration of melanin, and therefore the color of the iris, is genetically determined. When two parents have brown or green eyes, their child has about a 75% chance of having brown or green eyes as well. On the other hand, if both of them have blue eyes, they can be pretty sure that their baby will keep the blue eyes they were born with for life. You should also know that the brown color is said to be “dominant”. A baby with one parent with brown eyes and the other with blue eyes will more often inherit the darker shade. Finally, two parents with brown eyes can have a baby with blue eyes, as long as one of his grandparents himself has blue eyes.

It usually takes between 6 and 8 months to know the final color of baby’s eyes.

It happens that the same person has eyes of two colors. This phenomenon, known under the name of “wall eyes”, bears the scientific name of heterochromia. When this heterochromia is present from birth, it has no effect on the health or visual acuity of its wearer. If it occurs following a trauma, or even without an apparent cause, it requires a medical consultation because it can be the sign of an injury.