Eye Health Central

Brown Eyes: Fun Facts About The World’s Most Common Eye Colour

Brown Eyes: Common but magnificent

brown eyes facts

It’s no contest: brown is the most common eye colour around the world. According to the most recent statistics, roughly 80 percent of the global population could be classified as having either light or dark brown eyes. So, chances are quite high that the eyes reading this article are some shade of brown!

While brown can’t be considered a “rare” eye colour, people who have brown eyes enjoy a few noteworthy benefits. Not only can brown eyes protect against harmful UV rays more than light coloured eyes, some scientists believe brown eyes could predict positive personality traits. Below, we’ll explore a few of the most interesting facts surrounding this widespread eye colour.

Actually, Everyone Has Brown Eyes

Before we explore why brown eyes are so common, it’s important to note that everyone technically has brown eyes. The reason for this has to do with a pigment called melanin.

You may have already heard about melanin in relation to skin and hair colour. Since melanin is a brown pigment, it makes sense that people who have more of this chemical in their body are more likely to have darker skin and hair. The same is true for eye colour.

Everyone has some degree of melanin in their irises. Melanin does a great job absorbing light, so people who have more of this chemical in their eyes tend to reflect back darker shades of brown. By contrast, light is better able to penetrate irises with less melanin, which means the colour that gets reflected back appears lighter.

In short, anyone who appears to have a lighter eye colour actually just has less melanin in their irises.

Why Doesn’t Everyone Have Brown Eyes?

About 10,000 years ago, most scientists believed everyone in the human race had brown eyes. The reason this is no longer the case could be explored from two angles: genetic and environmental.

Genetics Of The Eye Colour Split

On the genetics side, researchers at the University of Copenhagen recently discovered that one person in Europe expressed a genetic mutation for blue eyes between 6,000 – 10,000 years ago. This means everyone who has blue eyes could trace their lineage back to this one ancestor.

Biologists believe Europeans must have viewed these blue eyes as a very desirable trait. As the centuries wore on, this genetic mutation became increasingly common in most European nations. Amazingly, over 85 percent of people living in Finland and Estonia now have blue eyes.

This genetic mutation could explain why people of non-European descent almost never have blue eyes. Indeed, babies born to African or Asian parents usually have a 100 percent likelihood of developing brown eyes later in life.

A Few Environmental Factors To Consider

While genetics certainly helps explain eye colour variation, it’s not the whole story. Scientists point out that differences in eye colour are also determined in large part by a person’s environment.

In general, people who live in warmer, sunnier areas tend to have brown eyes. Indeed, nations that experience harsh winters (especially in the Northern Hemisphere) are more likely to have a greater degree of eye colour diversity.

To explain why this is the case, we once again have to explore the fascinating properties of melanin. Besides colouring our skin, hair, and eyes, melanin plays an important role in shielding us from UV rays. So, it makes sense that people who live in nations subject to the brutal rays of the sun have more of this protective compound in their system.

In most Northern European nations like Iceland, Finland, and the UK, there’s less of a need for melanin’s UV protection throughout the year. Although scientists aren’t sure why this trait was discarded in the European population, the weather certainly appears to be a major factor.

Health Benefits & Drawbacks Of Brown Eyes

Additional UV protection is the most obvious health benefit of inheriting brown eyes. People with more melanin in their eyes and skin are far less likely to be affected by UV rays than people with less melanin. Brown-eyed people are also less likely to develop age-related macular degeneration and diabetic retinopathy than people with light eyes.

Just because brown eyes are less susceptible to the sun’s rays, however, doesn’t mean they’re invincible. Indeed, recent research has shown that brown-eyed people are far more likely than people with lighter eye colours to be diagnosed with cataracts later in life. So, no matter what eye colour you have, it’s a smart idea to invest in a pair of UV-protecting eyewear.

Brown, Hazel, Or Amber: What’s the Difference?

Brown, hazel, and amber pigments are officially considered separate eye colours. Despite this official status, many people struggle to accurately tell these colours apart. While these eye colours are quite similar, there are unique features you could look for to help you distinguish between them.

First off, hazel eyes usually have a very dark pigment around the outer circumference of the irises. These eyes also tend to change dramatically depending on an area’s lighting. Under bright lights, hazel eyes might look green with a few streaks of gold-yellow. By contrast, these eyes often look the same as brown eyes when in dimly lit areas. Due to this colour-shifting nature, some people refer to hazel eyes as “chameleon eyes.”

Unlike hazel, amber eyes don’t change as dramatically under different lighting conditions. These irises might look darker under poor lighting, but they should shine like a bright copper penny under proper lighting. Indeed, amber eyes have less melanin than both brown and hazel eyes.

If you’re really struggling to tell whether or not a person has amber eyes, take a look at a few pictures of dogs, cats, or birds. Although only 5 percent of humans have amber eyes, this eye pigment is very common in the animal kingdom.

The Social Perception Of Brown Eyes

An interesting report put out by Czech researchers analyzed how we subconsciously respond to people with different eye colours...and there’s some pretty good news for brown-eyed people.

For this study, scientists collected pictures of dozens of college students with different eye colours and facial structures. They then asked a group of about 200 volunteers to share their first impressions of each face. To double-check their results, scientists digitally swapped brown and blue eyes in all of the photos and asked another 100 participants for their opinions.

Interestingly, participants tended to view brown-eyed people as more honest than people with blue eyes. Researchers aren’t certain, however, whether trustworthiness was related solely to brown eyes or other facial characteristics.

Study authors noted that brown-eyed people were more likely to have certain facial features that are often associated with trustworthiness. This includes a round chin, broad mouth, and closed eyebrows. By contrast, blue-eyed people tended to have narrow mouths, long chins, and eyebrows that were far apart.

Anyone can read through this entire study in a 2013 edition of PLOS One magazine, which can be found on this website. This report was officially entitled, “Trustworthy-looking face meets brown eyes.”

What To Look Out For In Cosmetic Contacts

Thanks to the invention of coloured contact lenses, anyone can easily try out a new eye colour. Even if it’s not biologically possible, you’ll find a coloured contact lens on the market to suit your preferences.

Before you order your first pair of coloured contact lenses, however, it’s important to schedule an appointment with a certified optometrist. You need to get a contact lens fitting even if you’re planning on wearing non-prescription lenses.

Your optometrist will provide you with a prescription for contact lenses that will best fit your eyes. Wearing contact lenses that don’t fit your eyes could cause serious eye discomfort and even eye pain. 

Coloured contact lenses need looking after just the same as regular contact lenses. That means washing your hands before handling lenses, never exposing contacts to tap water, and taking these lenses out before going to bed. You should also throw away these lenses once their wear time has expired. 

Brown Eyes: Common, But Still Magnificent

In terms of percentages, brown eyes are pretty common but that doesn’t mean that they don’t have some fantastic qualities. As mentioned earlier you can see, brown-eyed people enjoy a few health advantages and even a slight boost in the trustworthiness department. Although they’re not as rare as blue or green eyes, brown-eyed people should feel proud of their many unique traits. If you're looking for the best contact lenses for brown eyes then visit this post

Author: John Dreyer Optometrist Bsc(Hons), MCOPTOM, DipCLP
Created: 27 Apr 2023, Last modified: 20 May 2024