Other names: mydriasis, dilated pupil

Due to the complex interconnection of nerve pathways and nerve fibers may pupils react to light or other current needs of the body – stress and danger extends to the visual perception of the highest quality, on the contrary, while resting narrowing. Its shares are also focusing on looking into the distance and near vision.

Determining the size of the pupil, whether the pupils are the same size on both sides, and whether the response to light is often done in emergency medicine because the abnormal behavior of the pupils correspond mainly to some acute conditions (but obviously not you). It must be stressed that for some people it is found unequal pupil size at birth – then, of course, not a pathological phenomenon.

For acute conditions may be an extension of one or both of the pupils sign: upheaval and oppression of the brain, intracranial hemorrhage, stroke, hyperglycemia with ketoacidosis, poisoning some plants, antidepressants poisoning and atropine.

It occurs also in overdose cannabinoids (marijuana), cocaine, PCP (angel dust), psilocybin (magic mushrooms) and LSD.

All these conditions require urgent intervention of the emergency services.

For non-acute conditions applicable breach nerve fibers controlling the width of the pupil or processes operating on the brain (tumor growth, leukodystrophy and others).