In the past, people believed they could predict their children's eye color by looking at the eye colors of their parents and grandparents. Based on the belief that brown eyes are a dominant trait and blue is recessive, you can guess what color the child's eyes would be.
Today, we know that eye color is not so easy to "predict". While genetics play a role, eye color is not the work of a single gene. There are several genes that contribute to determining eye color. The latter is the result of the amount and distribution of melanin in the iris of the eyes (iris - the colored part of the eye).
So while two brown-eyed parents are more likely to have a brown-eyed child, the outcome is not guaranteed.
- Most of the population have brown eyes.
- People with blue eyes have no melanin in the stroma, the front layer of the iris. The lack of pigment in the eyes causes light to scatter when it hits them, making the iris appear blue.
- Green eyes are the rarest. Only about 2% of the world's population has such eyes. The color comes from both melanin and the scattering effect of light when it hits the eye.
- People born with albinism often have little or no melanin in their bodies. As such, they usually have light blue eyes. In rare cases, they may have clear irises, which make their eyes appear pink or red.
Can eye color change?
Eye color can change in infancy. Many babies are born with blue eyes that eventually turn a different color as melanin develops in the stroma. Their eye color generally becomes permanent around their first birthday.
In general, it is rare for the eyes to change color. They may appear to change when the pupils dilate or contract, but this is because the pigments in the iris merge or disperse. In some cases, eye color may darken slightly during puberty or pregnancy.
Health problems such as trauma to the eye, neurofibromatosis, uveitis (a condition that causes swelling of the eyes) etc. - can change the color of the eyes.
