Looking at certain objects, we see others at the same time, so that we can evaluate the position of these things in space, size, distance to them, etc. How does this happen?
What is the field of view?
It’s not enough just to clearly see the surrounding objects. In addition, another important characteristic of eye health is the field of view. What does this mean? This term refers to the space within which all its points are visible with a fixed position of the eyes. To a large extent, this characteristic determines the throughput of the visual analyzer, since they are directly dependent. So the ability to see many surrounding objects is also very important.
The magnitude of the field of view varies quite a lot in different animals, and even in humans. This depends both on the anatomy and on individual characteristics and hobbies or professional activities, that is, on what can develop this characteristic.
Features of human vision
As many people know from the biology course, the position of the eyes in different animals varies depending on the diet. In herbivores and birds, they are located on both sides of the head, and in predators and omnivores in front. People obviously fall into the second category.
A person has binocular, or stereoscopic, vision, that is, he sees objects simultaneously with two eyes. At the same time, the brain connects individual images, giving an idea of the world around as a whole. Since the fields of view of different eyes in people intersect, in general, it can hardly be called wide. However, this helps, for example, to determine the position of objects relative to each other, etc.
A person’s field of vision is a curious thing. For example, this characteristic is different for different colors, in addition, it is completely asymmetric - most people perceive white color, and worse - green. Since the axes of the human eyes are parallel, it is best to see objects directly in front of them or where they are looking. However, not everyone sees it that way.
Vision in various animals
The axes of the eyes in animals usually diverge slightly, are not parallel. This is one of the reasons why they have panoramic vision. And the more it is
discrepancy, the more sideways the zone of visible space is elongated. In addition to the structure of the skull and the location of the eyes, oddly enough, the size and shape of the nose have a serious effect on the field of view. The combination of these and some other factors allows certain types of animals to see much more at the same time than people.
Due to the different structure of the eyes, in particular the same ability of the retina to perceive information on its entire surface, dogs, cats, horses and other representatives of the fauna have panoramic vision. At the same time, the sharpness leaves much to be desired. Having the opportunity to see more, animals perceive the world around them in less detail and a little blurry compared to people. So, about 60-70 degrees more space enters the field of view of a dog than in humans. For some breeds, such as greyhounds, as well as horses, this figure is even higher.
Lateral or peripheral vision
The asymmetry of the human perception of the environment is determined primarily by the size and shape of the optically active retina. And, paradoxically, the field of view of each individual eye is elongated in relation to the outer corner.
Rods and cones, providing the ability to see, are distributed unevenly on the surface of the retina. The former are located more or less everywhere, and the latter are only in the center. That is why central vision is much sharper than peripheral, since the rods do not give the necessary resolution, that is, the image generated with them will be less detailed.
For some people, the perception of visual information is more developed in connection with the scope of their activity or activities: driving a car, team sports, etc. There are even special exercises aimed at increasing the field and visual acuity. Still, human eyes are imperfect.
Blind spots
This may seem surprising, but people do not always see even what is literally in front of their eyes. Because of the structural features, there are so-called blind spots, and the objects located in them, oddly enough, are out of sight. How does this happen?
Anatomically, this feature is associated with the exit of the optic nerve, so there are no special cells in this section of the retina. Nevertheless, this usually does not bother at all, because the eyes are rarely fixed, they move almost constantly, and the blind spot is so small that this feature is simply invisible to most.
Anxiety Symptoms and Violation
The field of view is an important characteristic of eye health, which means that any problems should be noticed in time, diagnosed and appropriate treatment prescribed. Neglecting this is not worth it.
The narrowing of the visual field, the appearance of new blind spots and other perceptual problems can speak of such serious disorders as glaucoma, retinal damage, vascular diseases, optic nerve tumors or circulatory disorders in the blood vessels of the brain, and some others. Timely diagnosis can save the patient’s health and even life if there are no other symptoms and reasons to see a doctor.
Imbalance in the field of view is a serious problem, the study of which is carried out using the perimetric procedure. A movable white object is mounted on an arc-shaped rotating structure. The patient's head is fixed on a special stand, one eye is closed. At the same position of the gaze, the object is moved in an arc, while the subject reports when he is out of sight.
Development and training
People do not have the same field of vision all their lives. It expands with the development of eyeballs, which lasts up to 20-30 years. For example, in the period from 6 to 7-8 years, its value increases 10 times. By age, a slight asymmetric narrowing occurs.
Both people suffering from various disorders, and those who just want to expand the space that enters into their field of vision, can use various static and dynamic techniques and exercises for this. There are, for example, special tables with numbers from 1 to 25, which you need to find in order with a fixed position of the eyes. Physiologically it is impossible to expand the size of the optically active retina. However, it is possible to learn to better recognize objects, numbers and letters that are in the field of peripheral vision, that is, increase its severity. This will allow you to perceive and absorb much more information at once, increasing the throughput of the eye. Such techniques, for example, are extremely popular among fans of speed reading. In addition, it helps to improve concentration.
Why is it important?
It is believed that the main characteristic of vision is its acuity. However, this is not quite true. Indeed, with a small field of view, it does not give any advantages. The reverse situation is also true, only a combination of these characteristics enables people to see the way they are used to.
A wide field of view makes it possible to better navigate in space. This can be easily verified by placing rather narrow tubes to the eyes and trying to walk around the room. It will immediately become clear that this is extremely difficult. So a narrowing of the field of vision would greatly complicate human life.