Pupillary response

Patent Pending Pupillary response is a physiological response that varies the size of the pupil, via the optic and oculomotor cranial nerve. This response results in either constriction (miosis),[1] narrowing the pupil, or dilation (mydriasis), widening the pupil. Dilation of the pupil occurs when the smooth cells of the radial muscle, controlled by the sympathetic nervous system (SNS), contract. Constriction of the pupil occurs when the circular muscle, controlled by the parasympathetic nervous system (PNS), contracts.