What happens to the eye when you enter a darkened cinema hall from bright sunshine? Give reason for your answer.

at first we cannot see anything clearly when we enter the cinema hall from bright sunshine outside. This just for a short period of time. After that our vision improves. The reason behind that is, in bright sunshine the pupil of our eye is small and when we just enter the darkened room very little light enters our eye due to which we cannot see properly. After a while, when the pupil of our eye expands, more light enters our eye and we can see clearly.