What’s So Special About Blue Eyes?

Blue eyes mean a lot of things to different people. Are blue eyes inherently sad or cold? Many songs seem to tell us so. They’re exotic to much of the world, since only 8–10% of the world population has blue eyes. What is it about blue eyes in particular that fascinates us so? Well, there’s a lot to explain. Here are some surprising facts about blue eyes that explains why they’re so special.

Blue eyes aren’t really blue

This may come as a shock to many, but it’s true. Blue eyes are blue the same way that the sky is blue or the sea is blue. It’s actually clear, but because clear things scatter light, only the blue reflects back. It’s a weird natural phenomenon called the Tyndall effect. Here’s how it works: your iris is made up of layers that either have melanin (pigment) or don’t. If they’re all melanated, you have brown eyes. If none of them are, you have blue eyes. And if some are and some aren’t, congratulations, you have green or hazel eyes, which are even rarer than blue.

Some babies are born with blue eyes that change color

Many babies are born with blue eyes for the simple reason that they haven’t developed pigment in their irises yet. Some babies born with blue eyes will darken to green or hazel or even all the way to brown. You can never be sure of a baby’s eye color until at least a year after birth, sometimes longer. It depends when the melanin-producing genes kick in. This has led to some awkward problems in the past and has often been seen as proof of infidelity, but it’s really just genetics and biology taking its time. Nothing to get panicked over.

Everyone with blue eyes has a common ancestor

Blue eyes stem from a single gene mutation about 6,000-10,000 years ago. This means that back then, one person had a faulty gene that did not produce melanin in the iris. It also means that that one person had enough children and grandchildren to spread the gene into the general population until it became widespread.

Having blue eyes is a recessive trait. So two parents with brown eyes can have blue-eyed children! It just means both parents carry a recessive blue eye gene. Also, although rare, two blue-eyed parents can have brown-eyed children due to other gene factors. Genetics is complicated!

Blue eyed people are more sensitive to light

Just the same way that skin can get damaged by sunlight, so can eyes. The less melanin you have in your eyes, the more kinds of light can get in, and do more damage; brown eyes block more of the harmful UV rays. So people with light eyes should be extra careful and use sunglasses whenever possible. If you wouldn’t go out in the sun without sunscreen, you should protect your eyes as well. For the same reason, blue eyed people have more eye problems associated with screen use (from computers and cell phones) because those screens emit blue light. 

Are there any health benefits to having blue eyes?

Surprisingly, there may be. One study of women undergoing childbirth found that women with lighter eyes had less postpartum depression and an easier birth than those with darker eyes.

This is only one study, but it seems possible that if you’re sensitive to light all the time, you build up a little insensitivity to overall pain in general. No major study has been conducted on a large enough population to draw a definite answer.

On the flip side, some studies have found that light-eyed people have higher tolerance for alcohol and some medications.   

How come blue eyes seem to change color on their own?

Once your eyes have decided on a color as a baby, you should have that basic color all your life. But some people have blue eyes that sometimes look green, or gray, or even violet. Remember that your eye color depends on what your eyes reflect, filtered through a light or dark lens.

If your blue eyes sometimes turn green, it’s because of things reflecting around you. It could be yellow light, or it could be something you’re wearing, or makeup, or the color of the room you’re in. It all depends on different things. It’s literally just a trick of the light.

Are there any drawbacks to having blue eyes?

There are a few. For example, if you have blue eyes, they’re more likely to show up red in photographs (again, it’s the light rays that are at fault).

On the other hand, your night vision is better if your eyes are lighter, but you get glare during the day. Some sports players wear dark contacts to counteract this effect on the field.

Overall, though, the difference between blue eyes and other colors is a matter of aesthetics. Rock ‘em if you got ‘em!

Related: What’s So Special About Gray Eyes?