Your pupils quickly dilate when you enter a dark room, letting in more light to help you see.
Your pupils quickly dilate when you enter a dark room, letting in more light to help you see. Once you're in brighter conditions, they contract accordingly.
This reflex is well-known, but pupil dila… [+4857 chars]
This reflex is well-known, but pupil dila… [+4857 chars]