Prior to World War II if you mentioned “baby blues”, it would have been understood that you were referring to eye color. Now, a reference to “baby blues” might refer to the feelings of depression experienced by some mothers following childbirth. This is especially true following the birth of the second set of twins or triplets. However, I am referring to the blue eye color and the variants green and hazel. Most babies of European decent are born with blue eyes giving rise to the expression “baby blues.”
As it turns out, a baby’s blue eyes might change color during the first year and the eye color could change to green, hazel or even brown. It is worth noting that no human eye has blue pigment. The only pigment in human eyes is brown (melanin). Blue eye color is caused by a lesser amount of the brown pigment required to produce brown eyes. Eye color is actually determined by the way light waves are reflected back out of the eye in much the same way as the sky is colored blue. Brown eyes result from high concentrations of brown pigment in the iris which causes light of both shorter and longer wavelengths to be absorbed. In blue-eyed people, the shorter wavelength light is reflected back resulting in the blue color.
Blue eyes occur in all parts of the globe, but brown eyes make up 75-90% of the world’s eye color, and it is believed that all humans had brown eyes up until ten thousand years ago. It is also believed that blue eyes are the result of the mutation of a single individual in Europe which led to the development of blue eyes according to the theory of Hans Eiberg, associate professor in the Department of Cellular and Molecular Medicine at the University of Copenhagen. It should be noted that professor Eiberg’s theory fails to explain how a single individual was able to spread his eye color throughout the world population. Blue eyes are common in northern and eastern Europe around the Baltic Sea, and DNA studies on ancient human remains confirm light eyes were present tens of thousands of years ago in Neanderthals, who lived in Eurasia for 500,000 years. Currently the earliest blue-eyed remains of Homo Sapiens were found in Sweden and were 7,700 years old.
According to Brandon Gaille’s market based research, the percentage of the population with blue eyes of the United States is on the decline and now stands at 17% while worldwide blue eyes are 8% of the population. However, in Finland and Estonia, 89% of their population has blue eyes. In Ireland, 57% of the population has blue eyes, and 29% of the population has green eyes. In Iceland 89% of women and 87% of men have either blue or green eye color, but a study of Icelandic and Dutch adults found green eyes are much more prevalent among women. Worldwide green is the rarest of eye colors and occurs in 1-2 % of the population.
As a disclaimer, I should say that the numbers used in eye color worldwide varies greatly depending on the source. Apparently eye color distribution has not been well studied, but the study of eye color over all has led to some interesting findings. Brown eye color has been associated with lower pain tolerance, increased sensitivity to alcohol, lower sensitivity to bright light, lower night vision, and quicker reaction time. Exploratory research conducted by the University of Pittsburgh with 58 healthy pregnant women determined that women with blue or green eyes had a higher threshold for pain compared to their brown-eyed counterparts before and after labor. The research team of the department of psychology at Georgia State University found that blue-eyed subjects were less sensitive to alcohol and therefore consumed significantly more alcohol than brown-eyed subjects. They concluded that the greater sensitivity to alcohol in brown-eyed people resulted in reduced alcohol addiction. The study concluded that blue-eyed people are more likely to abuse alcohol than brown-eyed people. This lends credibility to the old Western movie notion that you should not give “fire water” to “red men.”
Melanin is thought to protect the eye by absorbing light. Therefore brown-eyed people have more melanin and are less sensitive to bright light than blue-eyed people. On the other hand, blue-eyed people are more sensitive to light and more prone to macular degeneration. So, as ZZ Top would say, “Get yourself a pair of cheap sunglasses.” People with blue eyes have a better night vision than those with dark-colored eyes. From an evolutionary standpoint it seems to make sense. Since blue-eyed people evolved in the northern part of the world, where there are long dark winter nights. It is believed that blue eyes help man navigate their dark domain. Apparently evolution did not work the same for the Inuit or Sami Laplanders herding reindeer. A study by the University of Louisville found that brown-eyed subjects had better reaction time and motor skills when performing tasks such as hitting a ball or boxing. It should come as no surprise that the baseball legend Babe Ruth used a Louisville Slugger and was brown-eyed. The study found blue-eyed subjects were better at tasks such as bowling and golf. This could explain why golf was developed in Scotland.
While the study of eye color has produced some unusual findings, it is interesting to consider that all blue-eyed people could trace their ancestry to a single individual with a mutated gene meaning that all blue-eyed people are related. Since this is not yet settled science it could well be that blue eyes are the result of visit by a blue-eyed extra terrestrial in our ancient past. Either way eyes are fascinating and blue eyes, well they are captivating, but it is the vision that matters, and “Sometimes the heart sees what is invisible to the eye,” according to H. Jackson Brown. Jr.
Until next time…