For the most part, people admire colored eyes and have a tendency to stare at them. Nobody really thinks about where the eye color comes from or of any positive or negative factors that come from having colored eyes. The color of the iris is controlled by the amount of melanin in the Iris Pigment Epithelium. Melanin also controls the color of the skin and hair. Blue eyes have smaller amounts of melanin in the stroma of the iris than brown eyes and tend to have light hair color and light skin color. The shorter wavelengths of visible light are reflected from the dark epithelium and a phenomenon known as Rayleigh scattering occurs. Rayleigh scattering is the reason why the sky looks blue to us. Beautiful blue eyes and beautiful blue skies, thank you Rayleigh scattering.

Blue eyes are most common in Northern Europe and due to emigration from this area there are people with blue eyes in many other regions of the world. Researchers were able to find which base-pair was common in all individuals with blue eyes and light hair and not in the brown eyed and dark haired individuals. This change is what caused the iris to make less melanin, giving their eyes the lighter color. The mutation was dated to have taken place around 10000 years ago. It is believed that everyone with blue eyes has a single common ancestor.

Blue eyes are similar to a recessive trait. It is controlled by the interactions of a few genes, known as a polygenic trait. At first, everyone had brown eyes and the mutation may have only happened to a single person. This mutation resulted in a limitation of melanin production and could no longer be or make brown eyes. This mutation took place in the HERC2 gene, more specifically in the 86th intron, which checks with the OCA2 gene promoter. This mutation affecting the OCA2 is acting as a faucet. The more you open the faucet the more melanin will be made and cause the brown eye color. The mutation caused the faucet to close a bit to restrict the melanin being produced. It doesn’t entirely close the “faucet” however because if the OCA2 was turned off then no melanin would produced and cause a different condition called albinism.

An interesting statistic about beautiful blue eyes is that this condition is steadily decreasing. Less American children are being born with blue eyes. In 1905, 57.4 percent and in 1951 33.8 percent were born with blue eyes. This color of eyes is becoming less common where now only 16.6 percent of American children were born with blue eyes. The percent of people that have blue eyes in the world is 2.2.

So are there any benefits from having blue eyes? People with blue eyes are supposed to see better colorations, but in areas with high-glare situations brown eyed people seemed to see a lot better. Also, people with sensitive blue eyes have a higher chance of cataract development.