Why do we need peripheral vision

Peripheral vision is vital

October 2019

One increasingly encounters people, absorbed in their smartphone, apparently not perceiving their surroundings. If you walk up to them, they look up briefly and you walk past each other. How does it work that people who look concentrated on a small area still perceive an approaching person?

There are two types of vision

The eye test measures central vision. This is the visual performance at the sharpest point of vision, the macula in the retina. With the visual cells of the macula (uvula) we can see sharply, centered, with high accuracy, in color, in three dimensions and at different distances.

Most of the other photoreceptor cells (rods) differentiate between light and dark and thus enable night vision. The rods also constantly take in the entire peripheral field of vision. This viewing area is blurred, but very large and has a high temporal resolution. Therefore, we can recognize movements in the side field of vision very quickly.

Central and peripheral vision complement each other

If the gaze is consciously directed to an object, the eye automatically focuses and we see clearly. At the same time, the side field of vision is unconsciously scanned. If the periphery recognizes danger or something interesting, the brain switches on central vision. This is what makes seeing as a unit possible. Space and perspective can be grasped, colors can be seen, light and dark can be differentiated and movements can be recognized.

Friend or foe?

Researchers at the Max Planck Institute in Tübingen https://www.mpg.de/10350654/sichtfeld-bewegung-lösungen have now shown that people at the edge of the field of vision are perceived much better than previously thought. The researchers suspect that "recognizing other people's actions out of the corner of their eyes is so important to recognize early on whether an approaching person has good or bad intentions." The person with the smartphone perceives the person approaching.

The problem with the smartphones

Nonetheless, accidents due to distraction by smartphones do occur frequently. If visual impressions from close range are mainly sent to the brain, attention in the periphery is reduced. In addition, the visual cells of the macula are overloaded if the focus is on the same spot for a long time. Central and peripheral vision is no longer properly coordinated, and sudden dangers in the side field of vision are not recognized in good time.

Narrowing of the field of vision due to diseases

Especially Glaucoma (glaucoma) is dangerous. The field of vision is slowly restricted without the person noticing anything. Glaucoma usually results from an increase in pressure in the eye. Other causes are

  • Retinal detachment or changes in the retina
  • Acute vascular occlusion in the eye
  • Circulatory disorders
  • Diseases of the brain and tendons
  • stroke

Good vision = quick response

Peripheral vision is vital. Together with the central visual acuity, good vision is created. You can contribute something yourself

  • Exercise and sports outdoors train peripheral vision
  • The eyes look relaxed away from the smartphone and into the distance
  • Glaucoma check from the age of 40
  • Regularly check central visual acuity

Road safety

The quick perception of our surroundings is important in road traffic. The ability to react to avoid accidents depends on rapid perception. If central vision is overloaded by long focusing on the smartphone, the entire visual recording is reduced and the ability to see is reduced. People with impaired vision react more slowly to rapidly approaching danger.