Why can't we see properly for some time when we go from a bright light to a dark place and vice versa

The pupil of the eye changes its size according to the intensity of light received by the eye. When there is bright light outside, the pupil contracts to reduce the amount of light entering the eye. When we move from a brightly lit area to a dark area, the pupil of the eyes is still small and little enters the eye. That is why we cannot see properly for a while. After some time, the pupil of eye adjusts it's size and expands to let in more light and gradually things start becoming clear.