Pupillary light reflex رفلکس مردمکی به نور

The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina. It appears black because light rays entering the pupil are either absorbed by the tissues inside the eye directly, or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil . Anatomical term created by Gerard of Cremona. In humans the pupil is round, but other species, such as some cats, have vertical slit pupils,