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.
One reason our eyes can change color is due to disease. So if you notice your eyes changing color, it may be a good idea to visit your eye doctor for a check-up. Some diseases which can cause your eyes to change color are Horner's Syndrome, pigmentary glaucoma and Fuch's heterochromic iridocyclitis.