Autumn and Eyes: A Spectrum of Brilliant Colors
Beauty, it’s said, is in the eye of the beholder. With the hills of Vermont alight in their annual cornucopia of brilliant colors from deep, resplendent reds to blinding yellows, what of the eyes beholding such natural beauty, and the kaleidoscope of colors they also light upon the world?
All visible color is caused by pigments. In the case of trees, chlorophyll gives the leaves their bright greens all spring and summer when there is abundant sunlight and warm temperatures. As the days get cooler and shorter, trees stop making chlorophyll, so other pigments called carotenoids and anthocyanins step up providing the reds, oranges, and yellows we’re peeping every day.
Our eyes have their own pigment that determines eye color called melanin. The melanin in the iris of the eye determines the eye color for all of us, but it’s our genetics that determine exactly how much melanin each of us has.
Genetics and the Color of Your Eyes
It is estimated that there may be as many as 16 genes that contribute to a person’s eye color, although only a couple are likely responsible for the bulk of the work known as OCA2 and HERC2. These genes passed down to children from their parents through chromosome 15 will determine the child’s eye color. While it is possible to make a fairly educated guess as to a child’s eye color based on their parents’ genetics, there are so many variations in the process that you can never be 100% sure.
Essentially, these genes provide instructions for producing proteins located melanocytes, which are then responsible for producing melanin. The more protein produced, the more melanin, the more likely you are to have eyes on the brown end of the color spectrum. The less protein, the more towards the blue end of the spectrum. The more pigment, the darker the eyes, and as it turns out, nearly 80% of people have brown eyes.
Now here’s the kicker – melanin only produces brown pigmentation; there is no blue or green pigmentation. The lower concentrations of melanin mean that more light can reflect visible wavelengths of light on the blue spectrum. Thus, somewhere between 8 and 10 percent of people out there have blue eyes.
The same thing happens with green and hazel eyes. The genetic mutations that cause there to be varying degrees of melanin in the iris less than that of people with brown eyes, means that more light scatters from the eyes making them appear green, or the darker hazel. Only 5% of people have hazel eyes, while only 2% are graced with green.
No Two Eyes or Leaves Are the Same Color
Much like no two snowflakes, or no two leaves -- no two people’s eyes are the same color. In fact, your particular eye color is as unique as your fingerprint. It may even be that each of your eyes differ from the other, however slightly.
Our eyes, much like the multitudinous colors sprayed across the hills right now, are a varied mix of colors and light. Our irises, the most visible part of our eye surrounding the dark center where the pupil is, controls all the light of the world we see coming into our eyes, and at the same time reflects light back out in colors from rich browns to piercing greens – a kaleidoscope of color we enjoy all the seasons of the year.