An ophthalmologist explained a person's ability to see patterns and glimpses of light in the dark

There are several good reasons why many people, including children, are afraid of the dark. When the lights are off, a person can see faint colors and flickering shapes moving in the dark. In low-light conditions, he may suddenly notice movement in his peripheral vision, and with the addition of active imagination, imagine any frightening creature. This was reported by Popular Science magazine on October 29.

"We usually consider our vision to be very accurate. We see what really exists. There is neurology, there is biochemistry, and [vision] can be deceived. There are so—called optical illusions that help illustrate the real physical and chemical processes underlying vision," says Dr. Scott E. Smith, professor of clinical ophthalmology at Columbia University Medical Center. Brody.

A person can check this on their own: close your eyes, gently press your finger to the upper edge of the eye socket, move the pressure down to the eyeball and move your finger from side to side. As a result, you can see a bright ring moving to the opposite place from the finger position. This is an example of the visibility of a non-existent visual object, which the brain interprets as a light phenomenon in the absence of light. Visual sensations that occur during mechanical action on the retina are called phosphenes.

Even when the light is off, the retina of the eye does not stop working. In low-light conditions, photoreceptors sensitive to it become more active. Since the cells are located mainly on the periphery of the retina, a person can more often notice movements in peripheral vision.

"In the dark, the retina is more or less active than in the light. It's just that the activity is mainly controlled by the cells that are turned off, not the ones that are turned on. And even the most minor changes or quantum variations in activation stimulate the neural network, even if there is no light around," Brody noted.

According to the publication, there are many chemical and neurological processes going on here. This indicates the ability to "see" things that are not really there. At the same time, what a person "sees" or feels as if he sees in the dark is a visualization with his eyes closed (VZG).

Contrary to popular belief, when immersed in total darkness or with eyes closed, a person does not see blackness, but a specific, uniform dark gray color called eigengrau (literally— "own gray"). At the same time, a person does not see complete black due to visual noise caused by signals from the optic nerve, which the brain perceives as flashes of light.

According to Brody, the bottom line is that there is noise in the visual system, which becomes the predominant sensation in the absence of light. This does not mean that visual noise exists exclusively in the dark. When the retina perceives a lot of information about the world around it, a person is not able to truly see the noise superimposed on top. However, it will be difficult to ignore it when disabling everything else.

It is emphasized that in addition to vision, there are other factors that can create a feeling of something being present in the dark. When the retina of the eye does not receive enough information, other senses are activated, so you can hear even an uneven rustle in the dark.

SM-Clinic ophthalmologist Svetlana Mirgorodskaya, in an interview with Izvestia on October 20, spoke about the main causes of the feeling of sand in the eyes. According to the expert, along with this, a person usually experiences burning, dryness, redness and a feeling of eye fatigue. These symptoms are often caused by inflammation or irritation of the mucous membrane due to dry eye syndrome.

All important news is on the Izvestia channel in the MAX messenger.