Oh, brown Eyes with long black lashes,

Young brown Eyes,

Depths of night from which there flashes

Lightning as of summer skies,

Beautiful brown Eyes!

In your veiled mysterious splendour

Passion lies

Sleeping, but with sudden tender

Dreams that fill with vague surmise

Beautiful brown Eyes. (...)

                        Mathilde Blind

Blue eyes so full of life

A wonder all of their own

So beautiful and precious

Oh to see those eyes smile

Such a beautiful sight

How I love to look into those eyes

When I look into them

A kind of peace comes over me

Beautiful blue eyes

Always haunting me

...teasing me (…)

                     Grace Hays

Eye color is often the first thing we notice about a person. The color, clarity, and brilliance of someone’s eye color can change how they’re treated and what they can achieve. While more subtle than things like skin color and gender, eye color changes how we see each other. That includes how attractive you are to others.

How is eye color determined?

Most people know that eye color is determined by genetics; your parents give you your eye color. In very rare cases, it could be your grandparents, and even great grandparents who 'gave you your eyes'. If your parents both have blue eyes, you’ll likely have blue eyes. If one or both have brown eyes, you’ll likely have brown eyes. If one parent has blue eyes, and the other has green eyes, you’ll likely get blue eyes… or green eyes… etc.

The complexity is in the two types of genes that we all carry that determine the eye color: dominant and recessive. Dominant genes are stronger and have a higher probability of dictating what your eyes will look like. However, it is still only a 'probability', not a guarantee.  While it has been believed that both parents with blue eyes are guaranteed to have a child also with blue eyes; the science says it is not always the case.

Eye color is governed by melanin. Your body produces melanin – the same coloring that makes skin brown from birth or from the sun. This substance makes the eye brown or green depending on the amount of melanin in the iris.

Caucasian babies, who are born with less melanin than African descended babies, are born with blue eyes. Their body may produce more melanin later and their eyes will change color. Children born with brown or olive-colored skin will typically have brown eyes.

Many light-colored eyes will change color depending on the lighting. This is because there are two layers to the iris. The upper layer for people with blue or green eyes is relatively transparent. That allows the light to be reflected by the lower layer and light diffraction by the upper layer will change the apparent color of the eyes.

Extremely rare is heterochromia. This is where someone naturally has two different colored eyes. It’s hereditary and harmless. Historically, it was a sign of the devil in someone’s soul. Today, we’re a bit nicer about it. In fact, many people find it very mysterious and attractive.

Another condition that appears to change the color of eyes is anisocoria. This is where the muscles of one pupil don’t contract. That gives the appearance that one eye is normal and the other is black. The most famous person with this trait was the late singer, David Bowie. Rumors that he had a glass eye were incorrect. In fact, he was punched in the left eye as a teen and, for the rest of his life, the iris didn’t contract correctly, giving him his legendary mesmerizing eyes.

Social Preference in Eye Color

Anyone who watches television or movies will notice the disproportionate number of people with blue eyes. There is a preference for blue eyes in actors and entertainers. This is driven by the fact that men show a sexual preference for women (and presumably men) with blue eyes. 1 Women apparently showed no preference.

Interestingly, though, people with brown eyes are deemed more trustworthy.2 While the test pointed to the idea that face shape was also a significant factor, there is a correlation between eye color and face shape genetically and the combination appeared to have an effect on subjects of the study.

Strange Eye Color Facts

According to an article in Psychology Today, people with dark eye color have a lower tolerance to alcohol. “The authors contend that heightened sensitivity to alcohol in dark-eyed individuals limits them from drinking the large quantities of alcohol that would lead to a physical dependence.” This was part of correlations that people with dark eyes have a higher sensitivity to drugs and physiological arousal.

Dark-eyed women experience more pain during childbirth, but also get greater relief from such things as epidurals. “Women with lighter eyes tolerated the pain of childbirth better than those with darker eyes and had less postpartum anxiety and depression. In addition, the women with dark-colored eyes experienced a significant reduction in pain with an epidural, suggesting greater pain sensitivity.” This certainly doesn’t mean that women with brown or hazel eyes shouldn’t have children but go for the painkillers. They’ll work great for you.

Light-eyed people are more sensitive to light. Since there is less pigment to protect the eyes, light has a greater impact. This doesn’t mean that people with darker eyes have better vision, but over time, it’s possible that UV rays and light can affect a light-eyed person more. Dark-eyed people’s pupils appear to react to light better. 3

Is it Better to have Light or Dark Eyes?

Even if the science says that there are advantages to one or the other, they appear to cancel each other out. Blue-eyed people might be considered more attractive, but brown-eyed people are more trustworthy. Light-eyed women can tolerate birth pain better, but dark-eyed women respond to drugs better.

All in all, eye color differences are fun to look at, but they ultimately have little effect on one’s life. Knowing how the world’s subtle biases might affect you is good, but none of the information so far available indicates that anyone should change their path because of their eye color.