The truth about green eyes

Green eyes may just be more enigmatic than any other eye color. And you don't have to dig too deep to realize that we are all pretty obsessed with this color. Green eyes have become a mainstay in literaturemusicpaintings, and photographs. The world was particularly blown away by a photo featured on the cover of the June 1985 issue of National Geographic. It featured a 12-year-old, green-eyed refugee named Sharbat Gula. "The haunting image of the green-eyed girl became an international symbol of refugees and of political and social unrest in the region," National Geographic reflected on their well-known cover dubbed "Afghan Girl."

Yes, green eyes are indeed captivating. Perhaps because of their mystique, though, legends and outright misconceptions about this eye color abound. Enter: the green-eyed monster. Those of you with this eye color are probably not too keen to be labeled a jealous beast, but that is just one of the many myths that surround this intriguing eye color. Curious to know the truth? We should warn you: it's even stranger than fiction.  

The most attractive eye color

If your eyes are green, you'll be happy to know that the intrigue surrounding the color has worked in your favor. In a comprehensive online survey conducted by AllAboutVision.com, people revealed what they thought to be the most attractive eye color. Congrats, greenies! You're at the top of the list. Over 20 percent of those who participated in the survey voted for green eyes, followed by 16.9 percent for light blue, 16 percent for hazel, and 15.2 percent for dark blue. Green even beat out gray and amethyst eye colors. 

Those of you with this attractive eye color also share something in common with some of the coolest celebs. Adele, Emma Stone, Gigi Hadid, Rooney Mara, Kate Middleton, Maisie Williams, and Scarlett Johansson are just a few famous faces with this same eye color. In fact, Johansson's eyes are so green that a Vanity Fair profile of the actress called her eyes "as pure green as a cat's." We're just saying you're in good company. And we're jealous.

Green eyes are a rarity

While it may seem like there are a whole lot of celebrities who have green eyes, this eye color is actually estimated to be one of the rarest eye colors in the world. According to World Atlas, those with brown eyes make up anywhere from 55 to 79 percent of the world's population, whereas those with green eyes make up just two percent of the global population. Two percent! Coming in rarer than green is gray — and that means true gray, not blue that sometimes looks gray — red or violet, and heterochromia (meaning two different colored eyes).

Additionally, only two percent of the population is estimated to have red hair — but there's actually a fairly decent chance that you can have both rare traits — à la Jessica Chastain. As Medical Daily reported, the majority of redheads have one of the three eye colors: brown, hazel, or green.

You can find many green-eyed people here

Okay, we know we just told you that green eyes are incredibly rare. And they are. However, if you were to take a trip to Europe, you'd probably start to doubt this fact. Edmund Custers, a biostatistician, revealed in an article for Owlcation that a whopping 86 percent of the population in Ireland and Scotland have either blue or green eyes. The situation is similar in Iceland, as 87 percent of men and 89 percent of women have one of the two colors. The expert further explained, "Among European Americans, green eyes are most common in people of recent Celtic or Germanic ancestry."

In fact, if you were to visit Britain, you might start to believe that green eyes are more prevalent than brown. According to a study of over 12,000 people conducted by ScotlandsDNA (via The Herald), brown eyes are rarer than green in Britain, despite the fact that brown eyes make up much of the world's population.

Irises only appear green

Although we may label people's eyes as "green," no one actually has green eyes. That is, irises only appear to be that color. According to Eyesite.co.uk, green eyes don't actually contain the color green. Instead, they're a "curious blend of light brown pigmentation, a yellowish lipochrome pigment, and a splash of Rayleigh scattering."

In an article for Owlcation, biostatistician Edmund Custers broke down this strange phenomenon. Basically, "green" eyes only contain a small amount of the brown pigment called melanin. In the absence of a lot of melanin, Rayleigh scattering happens. Rayleigh scattering is when, as Custers explained, "longer wavelengths of light pass straight through the eye, then they are absorbed at the back of the eye." He added, "Shorter wavelengths (blue wavelengths) are reflected and randomly scattered by the opaque layer of the iris." Brown eyes, on the other hand, absorb light because they contain more melanin. Although Rayleigh scattering is also responsible for making blue eyes, well, blue, green eyes are especially unique because of this "curious blend" of blue wavelengths and yellowish pigment.

No one is born with green eyes

You may not know if your child has green eyes until quite a while after giving birth. When first born, a baby has one of two eye colors: gray or blue. That said, immediately after birth, cells called melanocytes begin to secrete melanin, the brown pigment, in the baby's irises, explains Healthychild.org. This starts happening because melanocytes react to light and, um, you know, there aren't exactly any sunny days in the womb. However, this process isn't like glow-in-the-dark technology. You can't just take your baby into the sunshine and expect to see their true eye color after stepping back inside. Melanocytes can take up to a year to finish producing pigment.

That said, you should begin to have an idea of your child's eye color at around the six-month mark because the process starts wrapping up at around this time. If, after a year, your child has green peepers, you can be confident that they're there to stay.

The green genes

Instead of waiting a whole year to find out if your child is going to have green eyes, you might think it easier to comb through your family history for any prevalence of this eye color. However, it's not quite as simple as just tracking down eye colors. The Tech Museum of Innovation explained that there are many genes — and eye colors — at play.

"What we are taught in high school biology is generally true, brown eye genes are dominant over green eye genes which are both dominant over blue eye genes," the article revealed. "However, because many genes are required to make each of the yellow and black pigments, there is a way called genetic compensation to get brown or green eyes from blue-eyed parents." Yep, it's true: You and your partner don't have to have green eyes to have green-eyed children.

Today, scientists believe there are at least eight — and, more than likely, as many as 16 — genes involved in determining a person's final eye color. So, yeah, it might actually be easier if you just wait until your child's first birthday to figure out their eye color.

One sex is more likely to have green eyes

Although the science isn't exactly clear on why women are more likely to have green eyes, we just know that this seems to be the case. According to a 2013 study published in the Journal of Statistics Education, researchers Amy G. Froelich and W. Robert Stephenson of Iowa State University found that nearly 12 percent of male participants surveyed reported having green eyes, while nearly 18 percent of the female participants had green. Although the researchers noted that more data should be collected on the subject, these results are similar to other studies.

The Daily Beast reported that the 1985 National Longitudinal Survey of Youth reported that more women than men had green eyes. An additional study published in Nature Genetics in 2008 also revealed comparable results. Over twice as many Icelandic female participants than Icelandic males were discovered to have green eyes. This was also true in the Netherlands. Three times as many Dutch women than men were revealed to have green eyes.

People of any race can have green eyes

Green eyes are more prevalent in Europe, but biostatistician Edmund Custers confirmed that people of any race can have green eyes. Although most of the estimated 4.4 billion people in Asia are thought to have brown eyes, there is a population of villagers in northwest China with green and blue eyes and, in some cases, light hair. Located in the Gansu province, the village of Liqian has long been believed to have a connection to a lost Roman legion: the army of Marcus Crassus.

This belief was taken a step further in 2010 when some villagers participated in DNA tests. The Telegraph reported the results: Some villagers were 56 percent Caucasian. Yuan Honggeng, head of the Italian Studies Centre at Lanzhou University in Gansu province, revealed to the China Daily newspaper (via The Telegraph), "We hope to prove the legend by digging and discovering more evidence of China's early contacts with the Roman Empire." Though rare, green eyes may just be found across the entire globe.

It's not just a human thing

You might think that people are the only ones that can possess this rare eye color, but researchers from the Department of Entomology at the Smithsonian Institution and the North American Butterfly Association actually discovered an insect with the most beautiful green eyes. Called the "Ministrymon janevicroy," this species discovered in 2013 is described as having "olive green eyes." It can be found in Texas, Costa Rica, and Venezuela. Oh, and on the internet. But it's not just this pretty butterfly that has green eyes. Man's best friend is also capable of having this eye color.

Veterinary ophthalmologist Laura Proietto explained to The Dodo, "Much like many other details of our body who make us who we are, DNA is the culprit. The color of the eye is determined by multiple genes that program how much pigment is present in the iris itself." Cats — especially ones with mostly white or all white coats — can also have green eyes. 

The "green-eyed monster"

If you've ever been teased about your green eyes, you can thank ol' Billy Shakespeare. He was perhaps the first person to connect green eyes to envy. The Merchant of Venice reads, "How all the other passions fleet to air, as doubtful thoughts, and rash-embraced despair, and shuddering fear, and green-eyed jealousy!" Hmm. A few years later, the famous playwright again referenced the eye color in relation to envy. This time in Othello: "O, beware, my lord, of jealousy; It is the green-eyed monster which doth mock the meat it feeds on."

Did Shakespeare have it out for someone with green eyes? Did he just hate the color? We may never know for sure why Shakespeare chose "green eyes" to symbolize jealousy, but Phrases.org revealed their best guess. The color green was, and still is, often linked to sickness — "possibly because people's skin sometimes takes on a slightly yellow/green tinge when there are seriously ill." The site further speculated, writing, "Green is also the [color] of many unripe foods that cause stomach pains." 

The real green-eyed personality traits

While Shakespeare asserted that green eyes were emblematic of envy, "sexy" might be a more accurate description of people with green eyes. In a study published in The International Journal of Indian Psychology, participants considered green eyes to be "the sexiest of all the different colors." Hmm, perhaps it is those who do not have green eyes that are actually the green-eyed monsters. When asked to assign personality traits to those with green eyes, 29 percent of participants in the study considered green-eyed people as "creative" and "a bit devious."

Ophthalmologist and researcher Hamadi Kallel agrees that people with green eyes do share some similar personality traits. And it's not what Shakespeare thought. IHeartIntelligence.com quotes Kallel as saying that green-eyed people "have an air of mystery and a quiet self-sufficiency. [They are] often unpredictable, but slow to anger." She continued, "They are original, creative and perform well under great pressure."

There are health risks

Green eyes may be the most attractive, but they also come with some health risks. In fact, all people with light eyes may just be more prone to developing a particular kind of cancer. This is because, as Everyday Health explained, blue and green eyes contain less pigment than brown eyes. And, since pigment is what protects the eyes from cancer-causing ultraviolet light, people with light eyes have an increased risk of developing melanoma — specifically in the uvea, which is in the "middle layer of the eye."

"People with light iris color need to be diligent in wearing UV-protected sunglasses," Ruth Williams, ophthalmologist at the Wheaton Eye Clinic in Chicago, Ill. and former president of the American Academy of Ophthalmology, told the publication. Additionally, those with green eyes may also experience light sensitivity. Although people with green eyes have more melanin than those with blue, anyone with "light-colored irises do tend to be more light-sensitive," Williams explained. Thankfully, a simple pair of sunglasses — with UV protection, of course — can cut your skin cancer risk and help you avoid any of the eye irritation that comes with light sensitivity. 

People with green eyes can better tolerate childbirth

Sure, people with green eyes may have to deal with some light sensitivity and, yes, maybe even an increased risk of skin cancer, but apparently women with light eyes also possess a unique superpower. In a 2014 study conducted by researchers at the University of Pittsburgh School of Medicine in Pennsylvania, healthy female participants were split into two groups: dark eyes (brown and hazel) and light eyes (blue and green). By the conclusion of the study, researchers discovered that people with dark eyes experienced increased anxiety, sleep disturbance, and higher levels of pain during childbirth. The women with green and blue eyes, on the other hand, ended up experiencing less anxiety and better tolerating the pain associated with childbirth.

"Despite limited sample size," the researchers wrote, "this pilot study revealed patterns that suggest relationships between eye color and pain-related traits in this population." Unfortunately, researchers don't yet know why this unique correlation between pain tolerance and eye color exists.

And their liquor?

It's long been a stereotype that those of Irish descent can drink more than their non-Irish buddies. But like many stereotypes, this hasn't exactly been proven. In fact, experts don't think this has anything to do with genetics. "If you're in an environment where a lot of people drink, it's more common to find drinkers," Michael Fingerhood, associate professor of medicine at Johns Hopkins University School of Medicine, told ABC News. "In this case, it's very culturally dictated." However, there might be more to the story.

In 2001, researchers evaluated archival samples from two older studies — one of over 10,000 Caucasian male prisoners and another of nearly 2,000 Caucasian women. The researchers found that people with light eyes "consumed significantly more alcohol than individuals with dark eyes." The 2001 study further revealed that these findings are similar to other past studies, which cited that "dark-eyed people exhibit more physiological arousal and more sensitivity to some medications than light-eyed people." Based on their findings, the researchers speculated that people with brown eyes may be more sensitive to alcohol and, thus, don't drink as much. Whatever the reason, it appears that green-eyed people can indeed out-drink their brown-eyed cohorts.