Reflex Pupillary Breathing

The pupillary respiratory reflex (r. pupillaris respiratorius; synonym ocular respiratory) is a reflex in which the diameter of the pupil changes in accordance with the phases of breathing.

During inhalation, the pupil dilates, and during exhalation, it contracts. This occurs due to the fact that when you inhale, more air enters the lungs, the pressure in the chest increases and the venous outflow from the brain decreases. As a result, the smooth muscles of the iris relax and the pupil dilates.

When you exhale, everything happens in the reverse order - the pressure in the chest decreases, the venous outflow from the brain improves, the smooth muscles of the iris contract and the pupil narrows.

The pupillary respiratory reflex is one of the signs of normal functioning of the brain stem and autonomic nervous system. Violation of this reflex may indicate brain pathology.

Pupillary or labial respiratory reflex.

The oculo-respiratory reflex was first described by Brandt in 1897. It gets its name from two types of hetatoms. In 1923, Loeser suggested that the reflex originates in fish and is related to blood circulation. Such assumptions were confirmed by experiments on frogs. The reflex occurs regardless of whether the naked eye is open or the eyelid is closed. By observing the reflex, you can determine the presence of hemorrhages in the vitreous body, retinal detachment and eye tumors. It is simple and can occur without headache or vomiting. Disappears when using sulfur color or curvature of the ocular axis. It can be observed in healthy people immediately after closing the eyes. Sometimes the reflex disappears - pupillary reflex dysfunction.