Adaptation Dark

Visual dark adaptation is the ability of the human eye to adapt to low light conditions. This manifests itself in increased light sensitivity of the eye when in the dark.

When a person enters a dark room, at first he sees almost nothing. However, gradually the eye begins to distinguish the outlines and details of objects. This occurs due to physiological changes in the eye aimed at increasing its sensitivity to low light.

During adaptation to darkness, the pupils dilate, increasing the amount of light entering the eye. The synthesis of a special substance rhodopsin in the retina of the eye is also enhanced. Rhodopsin increases the sensitivity of light-receiving cells in the retina.

Complete adaptation of the eye to darkness occurs in approximately 30 minutes. As a result, a person can distinguish objects and move even in minimal lighting. This ability of the eye plays an important role in life, helping to navigate in conditions of poor visibility.

Dark adaptation is a visual adaptation of A., manifested by an increase in the intensity of light perception in conditions of reduced illumination (in the dark). This is the result of training the color-sensing systems of the visual analyzer. The physiological basis of adaptation is a change in the number of light-sensitive elements (cones and rods) and the concentration of visual pigment in them, as well as an increase in the light sensitivity of cones. The lower the illumination of the object, the longer the adaptation takes. A distinction is made between complete dark adaptation - after the complete disappearance of light - and incomplete or short-term adaptation, characteristic of weak light exposures. Dark adaptation is necessary for any human body, because it has a positive effect on both the visual organs and the body as a whole. The eyeball requires frequent “training” so that the organ can respond adequately to light.