When we look at certain objects, we see others at the same time, so we can estimate the position of these things in space, their size, distance to them, etc. How does this happen?
What is the field of view?
It is not enough just to clearly see the surrounding objects. In addition, another important characteristic of eye he alth is the field of view. What does this mean? This term is understood as 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 size of the field of view varies quite a lot both in different animals, and even in humans. It depends both on 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, depending on the diet, the position of the eyes in different animals varies. In herbivores and birds they are locatedon 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 with both eyes at the same time. At the same time, the brain connects individual pictures, giving an idea of the world around us as a whole. Since the fields of vision of different eyes in people intersect, in general it can hardly be called wide. However, it helps, for example, to determine the position of objects relative to each other, etc.
The human field of vision is a curious thing. For example, this characteristic is different for different colors, in addition, it is completely asymmetrical - most people perceive white as the best color, and green as worse. Since the axes of human eyes are parallel, they see objects best in front of them or where they are looking. However, not everyone sees it that way.
Vision in different animals
The axes of the eyes of animals usually diverge slightly, they are not parallel. This is one of the reasons why they have panoramic vision. And the more thisdiscrepancy, the more the zone of visible space is extended to the side. 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 influence 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 humans.
Due to a different structure of the eyes, in particular, the same ability of the retina to perceive information throughout itssurfaces, dogs, cats, horses and other fauna have panoramic vision. However, the sharpness leaves much to be desired. Having the ability to see more, animals perceive the world around them in less detail and a little blurry compared to humans. So, in the field of view of a dog, there is approximately 60-70 degrees more space than that of a person. For some breeds, such as greyhounds, as well as horses, this figure is even higher.
Lateral or peripheral vision
The asymmetry of 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.
Stands and cones, which provide the ability to see, are unevenly distributed over the surface of the retina. The former are located more or less everywhere, while the latter are located only in the center. That is why central vision is much sharper than peripheral vision, since the rods do not provide the necessary resolution, that is, the image generated with them will be less detailed.
Some people's perception of visual information is more developed due to the scope of their activities or activities: driving a car, team sports, etc. There are even special exercises aimed at increasing the field and visual acuity. Yet human eyes are imperfect.
Blind spots
It may seem surprising, but people don'talways see even what is literally in front of their eyes. Due to 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 area of the retina. However, this usually does not interfere at all, because the eyes are rarely fixed, they are almost constantly moving, and the blind spot is so small that this feature is simply invisible to most.
Worrying symptoms and impairment
Field of vision is an important characteristic of eye he alth, which means that any problems must be noticed in time, diagnosed and appropriately treated. This should not be neglected.
Narrowing of the visual field, the appearance of new blind spots and other problems of perception can indicate serious disorders such as glaucoma, retinal damage, vascular disease, tumors of the optic nerve or circulatory disorders in the brain vessels and some others. Timely diagnosis can save the he alth and even the life of the patient, if there are no other symptoms and reasons to see a doctor.
Visual field impairment is a serious problem that is investigated using the perimetry 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. With the same position of the gaze, the object is moved along an arc, while the subject reports thatwhen he is out of sight.
Development and training
People don't have the same field of vision all their lives. It expands as the eyeballs develop, which continues up to 20-30 years. For example, in the period from 6 to 7-8 years, its value increases 10 times. There is a slight asymmetrical narrowing towards old age.
Both people suffering from various disorders, and those who simply want to expand the space that enters 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 that need to be looked up in order with a fixed position of the eyes. It is impossible to expand the size of the optically active retina physiologically. However, it is possible to learn to better recognize objects, numbers and letters that are in the field of peripheral vision, that is, to increase its sharpness. This will allow you to perceive and assimilate much more information at the same time, increasing the throughput of the eye. Such techniques, for example, are extremely popular among fans of speed reading. It also helps improve concentration.
Why is this important?
It is believed that the main characteristic of vision is its sharpness. However, this is not quite true. After all, with a small field of view, it does not give any advantages. The reverse situation is also true, only the combination of these characteristics allows people to see the way they are used to.
Wide field of view allows better orientationspace. This can be easily verified by putting rather narrow tubes to the eyes and trying to walk around the room. It will immediately become clear that this is extremely difficult. So narrowing the field of view would greatly complicate human life.
