Essentially, green eyes are unique. Most common in Western, Northern, and Central Europe, green eyes often point to German or Celtic ancestry. Currently, they can be found most often in Iceland, the Netherlands, Scotland, Britain, and Scandinavia.
So where did our green-eyed ancestors come from? Most origins point to areas around the Caucasus Mountains, which link Asia and Europe. That may help explain why so many different countries and continents have had green-eyed populations for thousands of years.
The highest concentration of people with green eyes is found in Ireland, Scotland, and northern Europe. In fact, in Ireland and Scotland, more than three-fourths of the population has blue or green eyes – 86 percent!
The two main gene pairs geneticists have focused on are EYCL1 (also called the gey gene) and EYCL3 (also called the bey2 gene). The different variants of genes are referred to as alleles. The gey gene has one allele that gives rise to green eyes and one allele that gives rise to blue eyes.
Iris color is determined by our parents' eye colors mixed with a little genetic lottery. Green irises have an uncommon melanin level — less than “truly” brown eyes, but more than blue eyes. This is why green eyes are so unique.
The allele genes come in the form of brown, blue, or green, with brown being dominant, followed by green, and blue being the least dominant or what is called recessive. Given this information, you can determine what eye colors are dominant in the parents.
People with green eyes are more likely to have certain health issues. Green eyes are more prone to melanoma of the uvea, a type of eye cancer, than are dark eyes. The same is true for macular degeneration.
We found that green is the most popular lens colour, with brown coming in a close second, despite it being one of the most common eye colours. Although blue and hazel are seen as the most attractive eye colours for men and women they are surprisingly the least popular.
Proof of green eyes apparently has been found in Siberia during the Bronze Age, some 4,000 years ago.
At some point, you've probably wondered what the rarest eye color is. The answer is green, according to the American Academy of Ophthalmology (AAO). Only about 2 percent of the world's population sport this shade.
Green is considered by some to be the actual rarest eye color in the world, though others would say it's been dethroned by red, violet, and grey eyes. Green eyes don't possess a lot of melanin, which creates a Rayleigh scattering effect: Light gets reflected and scattered by the eyes instead of absorbed by pigment.
Of those four, green is the rarest. It shows up in about 9% of Americans but only 2% of the world's population. Hazel/amber is the next rarest of these. Blue is the second most common and brown tops the list with 45% of the U.S. population and possibly almost 80% worldwide.
The conclusion: Green eyes are considered attractive because it's a rare color. Common eye colors like brown, blue, even black, are typically seen all around because of its pigmentation. Green eyes, however, are rarely seen and that's what makes them appealing.