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 number and color of pigment granules (melanin) in our eyes. Newborns often have non-pigmented (blue) eyes, which will change and darken in the first six years of life. More or darker pigment means darker eyes, fewer or lighter granules result in lighter eyes.