THE PUPILLARY PATHWAYS
THE ANOMALIES of the pupillary pathways are manifold and intricate. Since it is a truism that to understand better the abnormal, one must know the normal, it would seem proper to review briefly a few salient points concerning these pathways.The size and action of the pupils are determined by the local state of the iris itself, the chemical events occurring at the myoneural junctions, the balance of neural stimuli flowing through the sympathetic and parasympathetic systems and the person's general emotional state. Of greatest importance concerning the local state of the iris is the condition of its blood vessels, relaxation (congestion or sclerosis) of the vessels resulting in miosis and constriction in mydriasis. Although all these factors seem at first glance somewhat distinct, they are so closely interrelated that it is only in unusual circumstances that one can determine their individuality.The normal pupillary diameter is