Question

A person from bright sunlight enters a poorly lit room and feels blinded for a short while.Why?

Answer 1

When a person from bright sunlight enters a poorly lit room he feels blinded for a short while, this phenomenon is known as light adaptation. It is a process of adjusting the diameter of pupil to low levels of illumination; cones cells meant for colours and fine details adapt first; rods works in dim light takes more time in order to adapt. In the bright light, cones pick up sharp images and colours. But once in low light, the cones become inoperative which leads to reduced vision. Slowly diameter size of pupil is adjusted and switchover between cones and rods takes place, which makes the light adaptation in the retina.