When a person moves from a darkroom into bright light, the pupil becomes

When a person moves from a darkroom into bright light, the pupil becomes smaller. The pupil is the dark, circular opening in the center of the iris of the eye that controls the amount of light that enters the eye. In dim light, the pupil opens up or dilates to let more light in, while in bright light, the pupil constricts or becomes smaller to limit the amount of light that enters the eye. So, when a person moves from a darkroom into bright light, the pupil automatically becomes smaller to prevent the eye from being overwhelmed by the sudden increase in light. This is a natural protective mechanism of the eye to prevent damage to the sensitive retina at the back of the eye.