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6 Unexpected Things You Might Not Know About Eye Colour

Jana loves researching and sharing facts about the natural world, science, and history.

Hazel eyes result from denser deposits of melanin.

Hazel eyes result from denser deposits of melanin.

1. Everyone Had Brown Eyes

For a long time, nobody wished for “more beautiful” green or blue eyes - because everybody had brown eyes. But around 10,000 years ago, something changed. Scientists believe that a single person was born with an eye mutation. The mutation gave us genes that can reduce the brown pigment inside an eye’s iris. Depending on how much pigment remained, this person’s descendants had blue, hazel, and green eyes.

2. Eyes Cause Winter Sadness

When the frosty season strikes, some people become so lethargic or depressed that they can barely function. The phenomenon is aptly called SAD (Seasonal Affective Disorder). SAD has many causes. The most surprising one? Brown eyes.

To get that perky feeling in the morning, the brain must know that daytime has arrived. When a person wakes up, the eyes absorb light and tell the brain, “Hey, rise and shine.” The brain then reduces melatonin in our bodies. This compound slows down our bodies and thinking (it’s nature’s way of helping us sleep).

Unfortunately, dark eyes need more light to wake up the brain. As a result, more melatonin is released during the fall and winter. This makes brown-eyed individuals more likely to get SAD.

Brown eyes remain the most common colour today.

Brown eyes remain the most common colour today.

3. Blue Eyes And Booze

When researchers looked at eye colours and alcoholism, the statistics were interesting. People with dark brown eyes had the lowest alcohol dependency rates. Those with green and grey eyes struggled a little more to let go of the wine glass. But a large study in 2015 noticed that most alcoholics had blue eyes.

The same study also found a genetic link between blue irises and alcoholism. The genes that determine their colour also influence other genes that play a known role in alcohol addiction. Unfortunately, since the genetic reasons for alcoholism are little understood, it prevents us from understanding how colour-related genes can bolster the craving for a drink.

4. Brown-Eyed People Appear More Trustworthy

In 2013, Czech volunteers looked at photographs of faces. When asked to rate the pictures for trustworthiness, they picked more brown-eyed people as “reliable”. Remarkably, even the blue-eyed volunteers felt this way. Next, the researchers digitally changed the brown-eyed faces. They gave them blue or green eyes but surprisingly, the same faces were chosen once again during the “Trust Test.” The reason for this was fascinating.

The study discovered that most brown-eyed people have similar facial traits. Light-eyed people also have their own set of features (which are less robust). The volunteers subconsciously sensed the features that belonged to brown-eyed people even though they thought they were looking at blue-eyed faces.

While not a concrete rule, people with light eyes seem to have more delicate facial features.

While not a concrete rule, people with light eyes seem to have more delicate facial features.

5. Your Eye Color Is Unique

Every human on Earth has its own unique eye colour. It’s not always obvious. The uniqueness is more about the fact that each person has a different melanin count than what one can see when you look at somebody’s eyes. This brown pigment is absent at birth, and that is why babies are all born with blue eyes.

As they age, some gain small amounts of melanin and develop grey and green eyes. The hazels and browns result from denser deposits of the pigment. But the children who keep their blue eyes do not lack melanin. Only the front part of a blue iris is colourless due to a complete lack of pigment. The back, however, develops its own signature amount of melanin.

6. Lasers Can Turn Brown Eyes Blue

Some people are born with brown eyes but prefer blue. One choice is to buy colour contacts. But since 2015, hardcore fans can now turn to laser surgery to tint their irises blue. The procedure remains unapproved in the United States, but for the small fee of $5,000, facilities in Costa Rica and Mexico will perform the operation.

The whole thing lasts about 20 seconds. The laser removes the brown pigment and makes the front part of the iris colourless – which essentially describes a blue eye. While the results are permanent, they are not instant. Patients must wait a few weeks for their body to slough the dead pigmented tissue before their eyes look blue.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2020 Jana Louise Smit


Jana Louise Smit (author) from South Africa on December 28, 2020:

Hi Peggy, thanks for another great comment. Each story has a link somewhere in the text that readers can click. It takes them to the original source where they can read more if they wish. Hope that helps. :)

Peggy Woods from Houston, Texas on December 24, 2020:

Another fascinating article from you. I was unaware that lasers could turn brown eyes blue, or that more people with blue eyes succumb to alcoholism compared to those with darker eyes. You should list your source links at the bottom of your articles so that people can read more if they desire.