Nature knows many examples of the peculiarities of vision in animals. Some species only notice moving objects, others only perceive certain colors. In this sense, a person was lucky to get the most versatile visual apparatus, although he is not without some shortcomings. For example, we have developed the so-called peripheral, or lateral, vision. Sometimes it fails. In what cases?
About human peripheral vision
The structure of the eye that nature gave people is imperfect, but it seems to be the most universal of the existing ones. A person is able to see well both near and at fairly distant distances. The field of view is quite wide, but at the same time we can focus on a single object. A good perception of colors, the ability to distinguish objects with a small amount of light - all this gives reason to believe that nature has generously endowed people.
Among other things, a person has a peripheral, orlateral vision. It is less sharp than the central one, but also serves other purposes. With its help, a person navigates in space, notices moving objects, can recognize an approaching danger, etc. This is possible due to the special structure of the retina, the cones on which are located not only in the central part, but also on the periphery, although they are much smaller. The total field of view includes up to 180 degrees horizontally and about 130 vertically. Specific values vary from one person to another, in addition, this ability can be trained by practicing according to special techniques.
Tunnel vision
In some conditions, a rather rare pathology is also observed, characterized by a sharp narrowing of the visible space. This phenomenon is called "tunnel vision" because it can seem to a person that he is looking around as if through a pipe. As a result, serious disorientation in space may occur, in addition, such a condition has a depressing effect on the patient. And it arises due to the fact that, for some reason, only the central part of the retina begins to perceive light.
When does it happen?
No ophthalmology clinic will help if you do not identify the cause of this extremely unpleasant condition. And they can be very diverse:
- oxygen starvation;
- serious blood loss;
- sudden pressure drop;
- hallucinogens and some other drugs;
- a sharp release of norepinephrine (the reaction "hit orrun");
- nitrogen poisoning (caisson disease);
- complications of laser therapy;
- cataract;
- glaucoma;
- retinal degeneration.
Depending on what caused the effect, tunnel vision can be either transient or permanent if it is an organic lesion of the eye.
Also, a violation of the field of view can be observed due to injuries, retinal detachment, disruption of the pathways, retinal nutrition, damage to the optic nerve, etc. By the way, there is a simple test that allows you to check peripheral vision, which you can do yourself. The subject simply extends his arms to the sides and wiggles his fingers, looking straight ahead. Normally movement should be seen.
How to treat?
There is no single scheme according to which doctors face such a symptom. It all depends on what caused the condition in which tunnel vision is observed. If it is a decompression sickness, then the patient is placed in a pressure chamber, in the case of oxygen starvation or blood loss, the deficiency is compensated.
But everything is more complicated when it comes to the chronic form. Fortunately, there are drugs such as "Emoxipin", "Taufon", etc., which have a beneficial effect on the restoration of peripheral vision. In addition, lutein also helps in this matter, although it is usually not easy to completely stop the process.
Forecast
Tunnel vision is not easydiscomfort. A person actually loses the ability to move independently, but without experiencing this on himself, it is impossible to imagine. With proper treatment of an acute condition, the negative effect quickly disappears and vision is fully restored.
If the organic lesions of the eye have gone far, treatment may not bring significant relief. Scientists are working together with doctors to solve this problem. Among the options offered, there are special glasses designed on the principle of binoculars, but vice versa. This invention is not popular because through such lenses surrounding objects appear very small, which does not improve the ability to orient in space.
There is another high-tech device that helps people suffering from disorientation due to tunnel vision. It consists of cameras and tiny screens in front of the viewer's eyes, onto which the outlines of objects that are outside the patient's field of vision are projected. Using this device requires some getting used to, but all the subjects confirmed that it became much easier for them to navigate in space with it.
