The human eye is an entire optical system, quite complex in its design.It contains biological lenses, which have their own separate and unique focus. This is the case when the light is refracted, the image is projected. And if the system works properly, the image will be clear. For the focal length there is a size, it is constant and depends on how bent the biological lenses.In healthy eyes, the average distance should not exceed 24 mm-this is the norm that equals the distance between the cornea and the retina.
When refraction of light occurs a process called refraction, which has its own measuring values - diopters.If the refraction occurs without any deviations, the image falls directly onto the retina and there it focuses. For the definition of the norm of vision is considered to be a unit or 100%, but this value is relative, depending on the individual case.
It is established that the visual acuity is 100% or V = 1.0, the eye refraction is 0, the IOP norm is 22-24 mm Hg.
The norm is considered to be a set of refractive and acute indicators, the pressure in this case refers to the external factors of evaluation, but in some cases plays a significant role, because is primarily reflected in the clarity of the view.
Why sharpness and refraction are key:
RefractionIs the position of the focal point relative to the retina. The optic system of the eye consists of the lens, vitreous, cornea and watery body. The incoming beam passes alternately through each refractive medium and reaches the macula - a small spot on the back of the eye, consisting of nerve endings, cones responsible for color perception, and vessels. A reflected ray projects the image and transmits it to the visual analyzer in the brain. And as a result, we see an image, and how much it will go to the analyzer is already a matter of refraction. With the normal functioning of the set of all systems, the focal point is on the surface of the retina, and this is called emmetropia (the indices are 0). Refraction is measured in diopters.
Visual acuityIs the ability of the eye to perceive two points at the minimum distance between them. Simply put, this indicator determines the quality of the reproduced picture in the brain. The difference between refraction is that sharpness does not have an exact mathematical model of calculus, unlike refraction. All designations for visual acuity are conditional and vary depending on the individuality of the organism.
Determine visual acuity through tables, while refraction is measured linearly, i.e., in fact centimeters / meters measure the length of the position of the focal point.When a deviation in sight is detected, the curvature of the cornea, the degree of image distortion, and diagnose one or a combination of the below listed diseases are determined.
What are the deviations
Due to the fact that the light streams are refracted incorrectly, that is, refraction breaks, there are various deviations in vision.Most often people begin to feel the blurriness of objects. Depending on the type of distortion, patients have such visual impairments:
Myopia.Perhaps the most common of the diseases in which the focus is not on the retina, but in front of it. Symptoms: decreased vision on distant subjects, rather rapid eye fatigue, discomfort in the form of rubbing, pain in the temporal parts of the head.
Farsightedness.In this case, the image focus is behind the retina. A person sees badly at a distance close to the eye. There is a fogging, a clear violation of accommodation on the face, strabismus may occur.
Astigmatism.There is an inability to focus on the retina. The basis of the disorder is the irregular shape of the cornea or lens. The main symptoms: image distortion, bifurcation of objects, fatigue after a short period of time (asthenopia), not releasing tension and, as a consequence, headaches.
Glaucoma.Complex of diseases on the basis of deviations from the norm of intraocular pressure. The increased IOP is more often diagnosed than the lowered, and has different consequences. With decreased development of atrophy of the optic nerve, with reduced retinal dystrophy. With severe damage to the optic nerve, a severe deterioration of vision is observed until complete blindness. This disease is treated only operatively and there are several different forms, among which there are irreversible ones.
Cataract. Disease of opacity of the lens with a progressive effect. The disease can occur at a young age, but mostly develops in the elderly. A person begins to react painfully to light, it is difficult to distinguish color shades, difficulties arise in reading, and vision falls significantly in the twilight and darkness.
Some diseases occur throughout life. This is due to factors such as the specifics of the work, daily eye strain, harmful production or inadequate working conditions. Often, such diseases can be inherited and even at an early age in children can be diagnosed eye diseases.
Preventative methods
These methods include:
Rejection of bad habits. Smoking causes spasms of blood vessels, and alcohol destroys the liver, which most directly affects the eyes.
A healthy and balanced diet will preserve the vascular system in a healthy way, and hence blood circulation will be at the proper level.
Vitaminotherapy of local and general nature. And what vitamins will help strengthen vision is described in this article.
Regular exercise helps improve blood circulation.
Avoid heavy loads, heavy loads, prolonged work at the monitor.
Do gymnastics for the eyes and palming - this allows you to keep your muscles toned and relax your eyes after a lot of fatigue.
Exercises
Among the most common and simple exercises can be identified several.They will help strengthen the muscle groups of the eyes, and thus stimulate the strengthening of the position of the cornea and the lens, blood circulation and enrichment of all parts of the eye with oxygen.
Sit straight and make several movements with your eyes several times: right-left, up-down, circular in one direction and the other. Blink.
Look into the distance and select an object to look at. A few seconds, hold your gaze. Then take a look at the point marked on the glass and focus your eyes on it. Again look afar. Blink.
Close your eyes tightly and open them. Repeat several times.
In order to relax your eyes, use the palm.An example of exercises for the eyes
According to Bates
A well-known ophthalmologist of the XIX century, who stated that the visual deviations depend on the overstrain of the groups of the oculomotor muscles, U. Bates invented a unique method of relaxing the eyes - palming. Nothing is required to use it.Except your own palms. Rub them to create heat, and attach to the eyeballs, lightly pressing the back side. Repeats several times. Mentally imagine a beautiful landscape or picture, remember the pleasant, and continue until you feel relaxed in the eye muscles. The indicator will be the fact that outbreaks begin to disappear with closed eyes.
William Bates Methodology
According to Norbekov
Gymnastics for Norbekov's eyes is based on psychological influence on the body with his own mind.That is a positive attitude, a belief in success, regular training and gymnastics, a constant smile and good eyesight "in your pocket". In fact, everything is not as simple as it seems and understanding the Norbekov method, will require considerable effort and patience, and most importantly, the appropriate attitude, so that skeptics should better abstain from this method.
On a number, with these well-known authors, there are several other methods, but they all have a similarity and have a common basis. Without the regular application of gymnastics in practice, the results can not be expected, as everyone who applies non-traditional methods to practice maintains.
The well-known author Zhdanov suggests doing the palming lying on the bed, so, in his opinion, there is a greater relaxation of all muscles.Covering his eyes with his palms warmed by his hands, it is necessary to lie until the flies completely disappear before his eyes.
To treat vision, you can use special eye yoga or other oriental methods. However, this requires special training and supervision by the instructor. To apply complex systems of recovery without the appropriate knowledge can be useless or harmful to health.
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conclusions
The norm of vision is a set of indicators of sharpness and refraction, which are responsible for the clarity and range of image display.With significant deviations, there are such diseases as myopia, hyperopia, astigmatism. For prophylactic purposes, it is necessary to regularly check the severity with the help of tables for vision, and to maintain or a slight restoration of the visual function developed methods and sets of exercises that have scientific justification.
