Henry-Gower reflex

The Henry Gower reflex is a reflexive movement of the pupil in response to bright light. This reflex was first described in 1873 by British physiologist John Henry. He was known as a follower of Horace Warren Gower. Despite the widespread recognition of this reflex, the question of whether it is congenital or acquired still remains open.

This reflex is considered vital for humans, as it protects the retina from excess light. Thanks to the pupil's ability to constrict and dilate, the eye can adapt to different lighting conditions. Constriction of the pupil in bright light helps maintain high sensitivity of the fundus, and dilation of the pupil reduces the amount of light falling on the retina and prevents blinding.

The reflex quickly manifests itself in newborns. Recent research shows that in infants under two weeks of age, the reflex is most often triggered by an unconscious sensation of discomfort, such as suckling at the mother's breast. As the baby adjusts to life outside the womb, the time during which the reflex remains inactive increases. Even after one year of life, the reflex is not stable, and with strong sound or light stimuli it can appear at various intervals. Moreover, research has shown that eye gaze training does not shorten the time it takes for the reflex to occur.

In adults, the reflex is activated when there is a sharp change in the level of illumination, for example, when moving from a dark room to a light one. This reaction is usually observed within a few seconds of exposure to the stimulus, after which the pupil returns to normal size.

Physiology of the Henry-Gower reflex. The reflex contraction of the pupil is controlled by a light stimulus. Adaptation of the eye to changes in brightness