Aberrant ocular parasympathetic innervation: an explanation to an unusual pupillary response.

A case has been reported where drinking fluid elicited pupil constriction on one side and dilation on the other. An attempt to give a neurological explanation to this abnormal pupil response is presented. It is postulated that aberrant parasympathetic fibers from the glossopharyngeal (IX) nerve will reach the eyeball via the pterygopalatine ganglion.