Some say your eyes are the windows to your soul. Are you filled with regret, joy, or sadness? Is your soul troubled or bursting with triumph? Your eyes will reveal it all if someone has the chance to look in them, many believe. What is not discussed as much is why our eyes' color can vary so much, from where our colors originate and how they came to be. Why does she have eyes the color of chocolate, yet his eyes seem to reflect the sea? From brown to green and “heterochromia,” the world’s eyeballs reflect our vastly varied genetic landscape.
Brown - 70% to 79%
You may have already noticed this fact: a majority of the world’s population has brown eyes. In fact, somewhere between 70% and almost 80% of people have brown eyes, making brown the most common eye color globally.
If you have brown eyes, it is likely because at least one of your parents does. Eye color is partially genetic, and the genes for brown eyes are thought to be dominant. This means that if one of your parents has an eye color other than brown, but one has brown eyes, you too will have brown eyes.
Your eye color is also determined by the way your iris scatters light as it passes through it, called Rayleigh scattering, and the amount of melanin in your skin. Melanin is a skin pigmentation produced by your body. The more melanin you have, the darker your eyes will be.
Blue - 8% to 10%
Blue is the second most common type of eye color on Earth in humans. Only between 8% and 10% of humans can boast having blue eyes, however. Interestingly, a genetic mutation thought to have occurred between 6,000 and 10,000 years ago is the origin of this eye color. The mutation resulted in a “switch” that turned off the genetic mechanism for brown eyes.
If you have blue eyes and meet someone else who does, you are said to share something else between you: one ancient, common ancestor.
Hazel - 5%
If you have hazel eyes, you have a combination of colors at play in your iris. These eyes are a mixture of green and orange or gold, almost like a cat’s eyes. While just about anyone can have this color, it occurs most commonly in North Africa, the Middle East, Brazil, and in people of Spanish ancestry.
Amber - 5%
Like hazel eyes, only about 5% of the world’s population has amber-colored eyes. This eye color is a light brownish, sometimes rusty. People of Asian, Spanish, South American, and South African descent are more likely to have amber eyes.
Gray - 3%
Yes, some people actually have eyes the color of your cat. People with gray eyes have irises that do not contain any melanin, and extra amounts of collagen in the eye called the stroma. This blocks blue coloring from surfacing in their eyes, resulting in a steely gray hue.
Green - 2%
Beckoning like glimmering emeralds, green eyes are some of the rarest in the world. Despite this, some areas have a huge concentration of green-eyed people. While rare elsewhere, green and blue-eyed people are so common in Ireland and Scotland that over 86% of the population has them. People are not born with green eyes, however, but grow into them. All babies are born with either blue or brown eyes, and they can develop green eyes by about 6 months old.
Green eyes are formed by a combination of light-brown and yellowish pigmentation, combined with Rayleigh scattering. Outside of Ireland and Scotland, people with green eyes live mostly in Northern Europe.
Red/Violet - <1%
It may be shocking to see red and violet in a list of eye colors for humans, but it happens in rare cases. Less than 1% of the world’s population actually have red or violet eyes. A person can appear to have violet eyes when they lack pigmentation in their eyes, and light reflects off their blood vessels. People with red eyes are typically albinos. The lack of pigmentation in their skin causes the blood vessels to appear, giving them red eyes.
Heterochromia - <1%
What the heck is heterochromia? This term refers to people who have eyes of two different colors. Some people have two colors within both eyes, and others have a different color for each eyeball. “Heteros” in Greek means different, and “chroma” means color. Unfortunately, this eye color can be linked with specific conditions such as Bourneville disease, Bloch-Sulzberger syndrome, and Recklinghausen disease.
While your natural eye color is not something you can choose, it is very important. The color of your eyes, like the color of your skin, is determined by nature best to protect you from the sun's UV rays. In theory, the darker your eyes are, the less damage the sun does to them on a bright day. Almost all babies are born with blue eyes, but this changes to brown for most people in the first few years of life. It is also true that your eyes may change as you age if you develop a disease that does so, or you experience another form of trauma that could influence your eye color. In short, eye color can be a fascinating topic that tells the story of your ancestry. Whether your eyes are brown, blue, green, red, or someplace in between, they will always be beautiful in the eyes of the beholder.