title: The opposite pupil in herniation.
abstract: I serially examined the pupil opposite the one already enlarged from transtentorial herniation in 13 patients. The main abnormalities, stereotyped in most patients, were an initially diminished light reaction with a 2.5- to 4-mm-diameter pupil, followed by slight reduction in size, and then reenlargement to greater than original size, all with preserved roundness. Subsequent deterioration varied among patients, but a transitional oval shape was infrequent and oculomotor function was preserved until both pupils were enlarged and fixed. Once the pupil on the side of a mass enlarges, heralding herniation, subsequent deterioration can be appreciated through changes in reactivity and size of the opposite pupil.
authors.affiliation: Neurological/Neurosurgical Intensive Care Unit, Massachusetts General Hospital, Boston.
authors.forename: A H
authors.initials: AH
authors.lastname: Ropper
mesh_terms: D004677:Encephalocele / Q000150:complications / Q000503:physiopathology*; D005133:Eye Movements; D006801:Humans; D011681:Pupil Disorders / Q000209:etiology / Q000503:physiopathology*; D012025:Reflex, Pupillary