This is maybe just a normal phenomenon in the visual sense. When your eyes are looking at light, or when a light beam enter into your eyes, part of the light is absorbed by the eyes, and part of the light is reflected out. In such condition, your eyes may appear a lighter color because of the light the eyes adsorb. But in fact, your eye color does not change at all. This is just a kind of optical phenomenon which you do not have to worry about. However, you should not usually let light directly shoot into your eyes in case that there are ultraviolet rays or infrared rays which can do harm to your eyes.