Barbara Marquand is a staff writer at NerdWallet, a personal finance website. Email: bmarquand@nerdwallet.com. Twitter: @barbaramarquand.
The eye may change color due to alteration of genes in the cells of the iris. This is because of your DNA factors in the body. The gene alteration can cause the eye to change color from brown to green and vise verse. There is no any explanation to the cause of the genes behaving in these manner. Prolonged exposure to the sun might also be another cause that made my eyes to change the color.
They go from a small amount of melanin, which you'll remember causes eyes to be blue, to a larger amount which means they'll be a different color. Usually this happens around six months, but eyes can change color up to about three years old. And the reason this only happens for Caucasian babies is because they tend to be born with less pigment than other ethnicities.