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.
The blue component of visible light can harm the retina but this is only caused by accidental exposure to sunlight or to very high intensity artificial lights so is rare. There is no consistent evidence that long-term exposure to blue light at lower intensity causes any damage to the retina. Long-term exposure to UV from sunlight may damage the cornea and cause cataracts but using artificial light normally is very unlikely to have any similar effects.