Eye color has long been a fascinating subject for geneticists, anthropologists, and individuals interested in human diversity. It's one of the very first things we tend to notice about others, and it often influences how we perceive a person's personality, ethnicity, and even health. But have you ever wondered why humans have such widely different eye colors? What are eye color percentages around the world? And how often is your eye color really among others?
Eye color percentages give an interesting insight into human genetic differences across the world. Some colors of eyes appear more often than others, some colors being more common in a particular region due to genetic descent.
Let’s explore how eye color percentages vary worldwide, how they’re determined, and some of the rare and unique hues that exist.
Eye Color Percentages Around the World
Globally, eye color percentages reveal interesting patterns about human diversity and migration. Here's a breakdown of how eye color is distributed around the world:
Brown Eyes (70-80%): Brown eyes are, by far, the most dominant in the world. Further, over 70% of the inhabitants of this planet possess brown-colored eyes, mostly in Asian, African, and South American countries. The reason behind this is a denser quantity of melanin present in the iris, which aids in making its color rich, deep, and brown. Brown-eyed people constitute the majority of any population, and this eye color enjoys the luxury of offering maximum protection against the UV light.
Blue Eyes (8-10%): Blue eyes are a dramatic feature that only about 8-10% of the world's population possesses. Blue eyes appear most frequently in Europe, specifically Scandinavia, Germany, and the United Kingdom. Blue eyes result from lowered levels of melanin in the iris, allowing light to reflect off the back of the eye more intensely, thus imparting blue color to it. Blue eyes have been linked with genetic mutations for thousands of years.
Green Eyes (2-3%): Green eyes are extremely rare and occur in only 2-3% of the global population. They are most commonly seen in people with Northern and Western European heritage, particularly in Ireland, Scotland, and Iceland. The green hue is due to a combination of a small amount of melanin and the existence of a yellow pigment called lipochrome. The low melanin content combined with the clear reflection of light causes this beautiful color.
Hazel Eyes (5%): Hazel eyes, which are a mix of brown and green, are found in about 5% of individuals. This color of eyes is especially prevalent in North America and some regions of Europe, where the differential quantity of melanin produces this multi-toned color effect in the eyes.
Gray Eyes (Less than 1%): Gray eyes are one of the rarest-colored eyes, and they tend to appear in parts of Eastern Europe. Gray eyes are similar to blue eyes but with even less melanin and a slightly different build, which causes them to be gray rather than blue. Due to the rarity of this eye color, individuals with gray eyes tend to have an elusive or striking look.
Other than these common colors, there are a few individuals who have yellow eye color, not a normal eye color, but generally a sign of liver problems or jaundice. It's important to distinguish this from the usual variation in eye color caused by genetics.
How Is Eye Color Determined?
How is eye color determined? It is primarily carried out by our genes and the melanin content in the iris. Melanin is one of the substances that determines the color of an individual's skin and also contributes a lot to eye color. The more melanin in an eye, the darker the shade will be. People with higher melanin content in their eyes primarily have brown or black-colored eyes, while people who have less melanin have gray, green, or blue-colored eyes.
Two genes are the key genes in determining eye color, and they are OCA2 and HERC2. The two genes assist in controlling melanin production and distribution in the iris. The OCA2 gene, for instance, controls the amount of melanin produced, while the HERC2 gene controls the functioning of the OCA2 gene.
A child inherits the eye color genes from both of their parents, but it's not necessarily as straightforward as blue-eyed parents having blue-eyed children. Genetics is unpredictable, and the interaction of dominant and recessive genes results in combinations that yield unexpected outcomes.
The color of eyes can also change because of aging, illness, or even illumination. Some cataract types can also cause eye color to change because of an alteration in the lens of the eye. In addition, illumination and the manner in which light is reflected inside the eye can, on occasion, make the color appear differently than it truly is.
Uncommon and Rare Eye Colors
While most people have eyes with normal brown, blue, green, or gray shades, there are specific rare and uncommon percentages of eye colors that are noteworthy:
Real-Life Red Eyes: Red eyes are also experienced by some of those with albinism as they do not have melanin in their iris. In those individuals, the absence of pigment in the iris allows the vessels behind the iris to become apparent, causing the eyes to turn reddish or pinkish. It is a genetic condition resulting from mutations of the OCA2 gene. Albinism is rare and affects about 1 in 18,000 to 20,000 people globally.
Yellow Eye Color: The Yellow color of the eyes is not a usual eye color but can occur as a consequence of liver disease or jaundice. When the liver is incapable of eliminating bilirubin, a yellow-colored pigment, from the bloodstream, it builds up in the bloodstream and yellows the eyes. This alteration of eye color is a symptom of an underlying illness and has to be attended to by a physician as early as possible.
Black Eyes in Black Individuals: While black eyes typically occur due to trauma, black individuals have eyes that are so dark, they appear black. They are very dark brown in color, and the overabundance of melanin within the iris makes the eyes appear black. Eyes like these are often deemed deeply beautiful due to the deep, dark color.
Heterochromia (Different-Colored Eyes): This is a rare condition where a person has two differently colored eyes or two differently colored eyes in the same iris. It may be inherited, or it may be caused by injury or disease, and it adds to the unique beauty of those who have it. While this condition is not common, it's not as uncommon as some people think, with celebrities like Mila Kunis and Kate Bosworth embracing their heterochromia.
In addition to the wide variety of eye colors, there are also fascinating examples of the smallest eyes in the world in humans. Microphthalmia is a rare condition where a person is born with underdeveloped eyes.
Conclusion
If you wish to know more fun facts regarding eye health and genetics, ensure to check credible research on the topic or reach out to professionals for further details.
Having information about eye color percentages is more than a curiosity regarding human differences; it uncovers information on our genetic lineage and what factors shape us as human beings.
