Auro-pupillary reflex

Auro-pupillary reflex - fast restriction and consequent slower dilated pupils under the action of sound in his ear. Described N.A. Shurygin (1901). A.-P.R. caused by irritation of receptors of a snail. Occurs when the power of sound, exceeding the threshold of audibility for the investigational not less than 25-30 dB. Used Auro-pupillary reflex for objective hearing. Note that when the effects of sounds great power (85 dB or more above normal hearing threshold) pupillary reaction can occur due to irritation of the sound vestibular receptors.