Defective vision. Ways of elimination of visual defects

A vision defect is what? The answer to this question you will learn from the article. In addition, you will receive information about which eye problems people face most often, and how to get rid of them.

general information

In medical practice, the visual defect is often called an abnormality of refraction. Such anomalies are the most common eye problems. The essence of this group of diseases lies in the fact that the optical system of the eye is unable to focus the light rays on the retina, which is our registrar of light stimuli. The main sign and consequence of this pathological condition is poor vision.

Defects of vision and its structure

This deviation may be of a different nature. Today there are several common visual defects, namely:

• astigmatism;
• Short-sightedness, or so-called myopia;
• Farsightedness, or hypermetropia;
• Color blindness, or color blindness;
• Color agnosia.

To understand why a particular visual defect arises, it is necessary to consider the peculiarities of the presented deviations in more detail.

Astigmatism

The cause of the development of this pathological condition is the incorrectly formed cornea of the optic organ. It should also be noted that the development of astigmatism is directly influenced by the displacement of the lens of the eye relative to the axis of refraction. Both named reasons entail differences in distances, which are extremely necessary for focusing the "picture".

Such a visual defect in one eye can combine the effects of hyperopia, myopia and normal vision.

Nearsightedness, or so-called myopia

Myopia can develop for several reasons. The first is the lengthening of the eye while maintaining the correct refraction. As for the second reason, this is too powerful optical refraction, which is more than 60 diopters, with the length of the visual organ within the limits of the norm. Both presented deviations negatively affect the obtaining of a normal image. In other words, the picture is not able to focus on the retina, but is located inside the eyeball. Thus, only a focused image of any objects located at a small distance from a person penetrates the retina.

To correct such a visual defect, patients are often prescribed special glasses, helping to build a clearer picture. In this case, a person can view objects in the distance without much stress. In order for the near-sighted patient to see more clearly, minus lenses are used that approximate remote objects.

Hyperopia, or hypermetropia

Such a defect develops due to excessively weak optical refraction in the visual organs while maintaining the normal length of the eyeball. It should be especially noted that the cause of farsightedness is the shortening of the eyeball, provided that the refractive power is preserved.

Due to the fact that the far-sighted eye is not able to create a focus on the retina, muscle tension increases significantly. This phenomenon gradually changes the curvature of the lens, which in turn leads to the adaptation of the visual organ to the prevailing conditions. However, this is not enough for the normal focusing of the resulting image.

When considering objects near the eyes, the muscular tissues of this organ are strained even harder. In other words, the closer the object is, the farther on the retina appears its image.

What are the ways to eliminate visual defects, or rather, hyperopia? To correct this deviation use glasses with plus lenses. They are quite good at building an image.

As you know, when a baby is born, his eyes squeeze a little horizontally. That's why all the young children are somewhat farsighted. However, in the process of development their vision gradually normalizes.

If the degree of hyperopia in a person is small, then sight in the distance and near can be normal. But at the same time people will complain about severe headaches and tired eyes. If the degree of hyperopia is average, then this is manifested by poor eyesight near.

Color blindness, or color blindness

Such a defect is a congenital disease, which is most often observed in men. The essence of this deviation lies in the fact that patients are disturbed by the correct perception of color, regulated by photoreceptor cells (cones) in the ocular retina. If any type of cone in a person is not enough, then he has color blindness.

Color agnosia

Color agnosia is a kind of deviation, such as visual agnosia. With such a disease, a patient with a persistent color vision may not correctly distinguish colors. There is also a simultaneous and letter agnosia. Diagnosis of such abnormalities requires careful examination by a neurologist. Determine the type of agnosia can be done with special tests.

Treatment of such a disease consists in active therapy of the deviation, which led to the defeat of individual brain areas. Very often, agnosia is not cured, bringing tremendous discomfort to the patient.

Visual impairment typical of classical migraine

Migraines with a typical aura are more common in males. In this case, patients may have visual disturbances. As a rule, they appear in the form of sparkling points, lightning flashes, zigzags, balls, after which a rather severe attack of headache develops. The intensity of such phenomena is observed for several minutes or seconds. Quite often the glittering images are replaced by the fallout of certain areas of the visual field. It should be specially noted that such violations are sometimes combined with numbness of the face, half of the body and tongue, as well as weakness in the limbs and violation of normal speech.