Oculosympathetic Response to Circulatory Arrest

REPORTS of the role of the sympathetic nervous system in anoxic mydriasis are not clear. A generalized sympathetic discharge occurs during systemic anoxia 1,2 , but some published data suggest that the sympathetic nervous system plays no part in the pupillary dilatation which occurs during anoxia and ischaemia. Little or no dilatation of the parasympathectomized pupil was observed during anoxia in the presence of an intact sympathetic innervation 3 . The pupil which has had an interruption of sympathetic and parasympathetic innervation dilates during asphyxia 4 .