Other names: meiosis, constricted pupil

Constricted pupils raised section of the nervous system called the parasympathetic. Therefore, the pupils constrict when the predominant activity of the system – at a time of peace – at bedtime, after meals, etc. Dilated causing sympathetic and it’s the opposite when activating the body – with fear, stress, surprise, shock, physical exertion, etc.

Narrowing or dilated pupils thus accompanies us every day and mostly therefore does not cause any concern.

At certain times, however, miosis a warning sign of certain serious conditions – e.g. poisoning opiates (such as heroin, morphine, codeine, methadone, …), organophosphates, carbamates(pesticides) and physostigmine (parasympathomimetic used in eye drops). The pupils are in such a case the size of a pinhead and the sick would find a whole range of other symptoms – low blood pressure, drowsiness, dizziness, vomiting, etc.

Other poisoning (amphetamine, methamphetamine, LSD, cocaine, …) result contrary pupil dilation.

Constricted pupils can also be found in people in a coma and other disorders of consciousness for various reasons – head injuries, brain tumors and inflammation, metabolic disorders and the like.