Why do babies' eyes change color? - Big Questions - (Ep. 211) | Mental Floss

Hi, I'm Craig. My eyes might be brown, but my heart burns red for you

And this is MentoFloss Video. Today I'm going to answer DoxyCirc's big question, Why are babies born with blue eyes

It's true that the majority of Caucasian newborns have blue eyes, but by adulthood, only one in five have them

That's because eye color can change for white babies. African, Hispanic, and Asian babies are typically born with brown eyes, which don't change color

Let's get started. First, let's talk about what eye color is. Whether your eyes are brown, green, hazel

or blue has to do with something called melanin. It's basically a type of pigment which can

also affect the colors of your skin and hair. Your eyes contain melanocytes, which are cells

that produce melanin. If there's a lot of melanin, the eyes are brown. If there's a medium amount, they're green or hazel. And a little bit means blue eyes

Another thing that affects eye color is the Tyndall effect, which is virtually identical to Rayleigh scattering

a concept you'll remember from our episode on whether blood is blue. I don't remember, because we do a million of these videos, and I'm usually drunk

But that explains why eyes may look different colors in different light. It doesn't affect whether eyes actually change color

Newborns don't have the levels of melanin that they'll eventually have. The amount increases over time which is why eyes often start blue then change to another color They go from a small amount of melanin which you remember causes eyes to be blue to a larger amount which means they be a different color Usually this happens after around six months but eyes can change color up to about three

years old. And the reason this only happens for Caucasian babies is because they tend to be born with

less pigment than other ethnicities. So does this mean that your biology teacher was lying to you and eye color is more about

melanin than genetics? Well no, it is genetic. They might have been lying to you about something else

I don't know. I don't know your biology teacher. that the genetics associated with eye color are more complicated than we once thought

You can't map it out on a simple chart because there are a handful of genetics that come together to affect eye color. In fact, experts predict that there are about 15 of them. Melanin

production is just a little piece of the puzzle. Supposedly there's a way to tell whether or not eye color will change by looking at

a baby's eye from the side, so that there's no light affecting your view. If there are hints of gold in the iris, you're rich! No, the eyes will probably become brown or green

over time. If the eyes are still very blue, they'll probably stay that way. This needs

to be properly studied though. And I'm not going to do it. Someone will eventually