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.
Eye color is based on the pigment (melanin) in your eyes. Eye color does not actually change day to day. Hazel eyes can appear to change color due to less pigment and effects from the exterior environment (clothing, lighting) bringing out specific colors more. Eye color CAN change with puberty and older age, related to genetics. Dramatic changes can indicate ocular disease -- see your eye doctor.