The Pupillary Reflexes And Their Neurological Importance.

The pupil is a circular opening in the center of the iris, its shape and size controlled by the iris. Usually three to four milimeters in diameter in normal room light, it may reach eight to nine milimeters when maxirnimly dilated. The function of the pupil js mostly optical. It regulates the amount of light reaching the retina. It increases the depth of focus and decreases the chromatic and spherical aberration caused by the lens and
cornea.