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.
If one is lucky enough to have hazel eyes, eye color may change naturally. Your eyes may lighten as you get older, or you may change eye color by artificial methods. Just remember, long term effects are not known; the most important factors are health and good vision.