I know that eye color can change with age. The color changes according to the pupil size and the iris color. That's the reason why the baby has blacker eyes and eyes will become brown when we get older. And some emotions can change the color of the eyes too. When someone is angry or loving, the color of their eyes changes. While if your eye color changes dramatically, you must see your eye doctor. Because certain eye color changes is a warning sign of some diseases. Be careful about that.
Yes, eye color will change in our life, but it changes slowly. I don't know why. But I think it is a natural phenomenon that we shouldn't worry about that. And it will not cause any side effect on our eyesight if it doesn't change quickly and obviously. If you don't like the color of your eye, you can change it with colored contact lenses. Do remember to have the eye doctor's prescription before you buy that!