What is the Origin & Reason for Blue Eyes?

What is the Origin & Reason for Blue Eyes?

Chapters:
0:00 Blue Eyes
1:44 Light Sensitivity
2:19 Origin of Blue Eyes
3:19 Theories on the Evolution of Blue Eyes
4:44 My Theory
6:54 What's Your Thoughts?
7:55 Support This Channel

When did blue eyes first develop and for what reason? Now I do have my own a theory about why blue eyes developed but I will share that at the end.

Firstly though, it does seem that all human beings initially had brown eyes, and they are still by far the most common eye colour today, with approximately 79% of people in the world having brown eyes. They result from a relatively high concentration of melanin in the stroma of the iris, which causes light of both shorter and longer wavelengths to be absorbed.
Blue eyes are much less common however, with approximately 8% to 10% of the global population having blue eyes. They are most common in Europe, particularly northern Europe, but found in people across the world, although many of these people have ancestry connected to Europe. This table shows the countries with the highest percentage of people with blue eyes in the world, led by Estonia, Finland, Sweden and Iceland.

Interestingly to note, there is no actual blue pigmentation either in the iris or in the vitreous body, as it is to do with how light is reflected. In people with blue eyes, longer wavelengths of light tend to be absorbed by the dark underlying epithelium, while shorter wavelengths are reflected and undergo Rayleigh scattering in the turbid medium of the stroma. This is the same scattering that accounts for the blue appearance of the sky. Blue eyes however do have lower concentrations of melanin in the stroma of the iris compared to brown eyes.

Now it does seem that blue eyes are more sensitive to light during the day, but are better at seeing in dim conditions compared to darker eyes. This is perhaps due to the lower levels of melanin in blue eyes. This logically makes sense as well.

Sources:

Does Eye Color Affect Vision? Does Eye Color Affect Vision? | Atlantic Eye Institute

List of cities in Europe by sunshine duration - Wikipedia

Eiberg H, Troelsen J, Nielsen M, Mikkelsen A, Mengel-From J, Kjaer KW, Hansen L. Blue eye color in humans may be caused by a perfectly associated founder mutation in a regulatory element located within the HERC2 gene inhibiting OCA2 expression. Hum Genet. 2008 Mar;123(2):177-87. doi: 10.1007/s00439-007-0460-x. Epub 2008 Jan 3. PMID: 18172690.

Olalde I. et al The Beaker phenomenon and the genomic transformation of northwest Europe. Nature. 2018 Mar 8;555(7695):190-196. doi: 10.1038/nature25738. Epub 2018 Feb 21. Erratum in: Nature. 2018 Mar 21;555(7697):543. PMID: 29466337; PMCID: PMC5973796.

Eye color - Wikipedia

People with brown EYES have a higher risk of developing winter depression - Mirror Online

Countries With The Most Blue-Eyed People - WorldAtlas

Why Did Blue Eyes Evolve? | Resource Center | Milan Eye Center

Melanin - Wikipedia

Western Hunter-Gatherer - Wikipedia

Eastern Hunter-Gatherer - Wikipedia

Early European Farmers - Wikipedia

Creative Commons Imagery:


Matteo De Stefano/MUSE File:Homo sapiens - Neolithic - reconstruction - MUSE.jpg - Wikimedia Commons Creative Commons Attribution-Share Alike 3.0 Unported license. CC BY-SA 3.0 Deed | Attribution-ShareAlike 3.0 Unported | Creative Commons

#blueyes #history #ancestry

[celtichistorydecoded]

Please let me know your thoughts below? Thanks for watching! 😀

[kilroy-cc]

I'm 62 with blue eyes and I have a hard time driving on the road at night. These new headlights are blinding me!

[DavidSmyth]

Europe was particularly heavily forrested before the arrival of agricultural. Which would have further reduced light

[ajrwilde]

Blue eyes are an adaption to CLOUD. Cloudy climates are low-light so light skin and eyes are an adaption. The Inuit don't have blue eyes because although they have low light in the winter they don't live in a cloudy climate like Europe.

[GreatRetro]

Estonian here. Estonians mostly have Gray/Silver eyes. I know that it is considered to be a shade of Blue, but you can deffenetly tell Blue from Gray appart!

[Occident.]

Im of Gael origin. Irish and Scots. Born on Tyneside England. Father had green eyes. Mother had bright blue eyes. I have light blue eyes. My 11 children have blue eyes as do my 21 grandchildren. We Celts are the most blue eyed people.

[Londonererer]

Makes sense, I'm comfortable walking about my house in the near dark, and I prefer lamps over bright ceiling lights, and start wearing sunglasses earlier in the year than other people, as the sun feels bright.

[byza]

I’m a blue eyed, fair skinned Australian… Descended from Scotland and England and to a lesser extent Denmark and Norway. I struggle with glare and bright light, so this vid makes sense… My eyes and skin have never looked so alive as they did in a frozen Berlin… Definitely something in that.

[nathanaustin]

This makes sense. I could never understand why my brown-eyed wife kept turning the lights on, even in the middle of the day.

[molecatcher]

The cloudy skies often found in Scotland and Ireland (even in Summer LOL) also cut down on the sunshine which may add to the effect of the short winter daylight hours.

[peterfitzpatrick]

I'm a green-eyed Irish ginger... 😌

As a welder, I do know that those with light blue eyes suffer arc-flash much more than other eye colours, I've often had it and its not nice... it feels like someone threw a handful of sand in your eyes & doesn't manifest until around 24hrs after seeing the flash...

For me, its a minor irritation but blue-eyed peeps can suffer very badly for days after...

😎👍☘🍺

[RCSVirginia]

As an older man in the lovely Italian film "Cinema Paradiso" told a young guy who had fallen madly in love with a girl, "It's the blue eyes."

[Gwenhwyfar]

They don't really know why Siberian Huskies have blue eyes either

[paddyo]

I come from a large Irish family …my mother had gray eyes father had hazel brown eyes they had 3 boys with brown eyes, 1 girl with green hazel, 1 girl green blue, 1 boy gray, and 1 boy deep blue eyes…

[alexj]

Rarer things are more precious, so i'm glad I have bluey green eyes.

[Proj_Doomsday]

Blue eyes, lighter skin, taller. Just like a plant reaching for light. That is how we humans adapted. The blue eyes, to adapt to lower light northern regions.

[DorchesterMom]

Ny husband and I are of Northern European descent. His eyes are an icily piercing light blue, mine are light green. It’s interesting to note that green eyes are also considered “blue” in most scientific literature.

Babies are either born with blue eyes or brown. In the case of blue eyes, it can take up to several years but, they can change to green. I had blue eyes until I was about three ❤

[lesleeestes]

I come from a mix of Irish, Scottish, German, English, and Swedish ancestors my eyes are blue green with a dark blue outer ring. They look more one color or the other depending on my mood and colors around me.

[brycewiborg]

This is interesting. I'm of Scandinavian heritage. From my paternal family we are 100% blue eyes. I had never given it any thought.

[MacNab]

I tend to think that the differing theories are not exclusive but rather complimentary. A combination of factors.