What Determines a Change in Eye Color?
Introduction
When children are born, they have gray-colored eyes. As the child ages through its first year, the eye slowly changes in color to one of the many common eye colors seen in adult eyes. Even adult eyes can change in color later on in life. It all depends on the reaction of the melanin in the eyes with its surroundings.
Melanin
On the iris of the eye are pigments called melanin. Melanin is the substance responsible for giving eyes their color. These pigments are usually on both the front and the back surfaces of the iris. However, the amount of pigmentation on the front of the iris will determine what color the eyes appear. If there is full coating of pigments on both sides of the eye, the eye color will most likely be brown. The less coating on the front of the iris, the more likely that the eyes will be green or blue. The intensity of the color of the eyes can also be affected by the iris. The intensity of the color will depend both on the size and the spacing of the iris fibers, as well as the size and spacing of the stromal cells in the eyes.
Infant Color Change
Infants are born with neutral- or gray-colored eyes but as their eyes are exposed to sunlight, the UV rays of the sun interact with the melanocytes in the eyes. This results in the melanocytes producing melanin. As the melanin develops, the eyes slowly change colors and usually reach adult pigmentation by the age of three.
Clothing
In adults, eye color changes can often determined by the way light reflects off of surrounding objects. Many adults may notice that their eyes change color when they wear certain colors of clothing. In fact, this is not the eyes changing color, but is actually the way in which light is reflecting off both the clothing and the eyes. Since eye color is nothing more than just the reflection of ambient light off the iris, wearing different colored clothing will change the colors of ambient light that are reflected off the iris resulting in the temporary color change. This is usually seen in people with a particularly light-colored iris
Stress
Stress may not change the color of the eyes completely, but it can affect how dark or light the eyes become in color. When the body experiences stress, the density and distribution of the melanin on the eyes changes. This can cause the eyes to look darker or lighter depending on whether the melanin has become denser or more spread apart.
Illness
Medications that are used to treat illness may also cause a temporary change in eye color in adults. This is especially seen in prostaglandin analog medications used for the treatment of glaucoma. These drugs mimic hormones that may as a side effect change the pigmentation of the eye resulting in a change of eye color.
Tags: change color, color eyes, adult eyes, ambient light, change colors