Nearsightedness, farsightedness, astigmatism

May 7, 2011

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Nearsightedness, farsightedness, astigmatism   - Diseases of the three of which are of the same nature. In order to better understand them, you must first remember what's inside the human eye. Recall that the eye acts as a collecting lens , I.e. the rays falling within a pass through the cornea and lens, whereby the refracted and collected on the retina.

That is the image focused on the retina, is perceived by us as what he saw. Accordingly, if a point of focus for some reason or other shifts, this leads to a change in vision. In one case, the person can clearly see distant objects, in another case, on the contrary, near. But the short-sightedness and far-sightedness, and astigmatism are violations of normal refraction, that is, the ability of the eye to light refraction.

So what changes in the refractive media can take place, and what they produce.

If the lens or cornea refracts light too, the rays converge on the retina is not, and in front of her. In this case, there is myopia, or as it is called, myopia . The same occurs when the eyeball receives an elongated shape, i.e. the retina "removed" from the focal point.

As a result, people are relatively well see what is near, as is reflected by the object a large number of rays and the image is relatively clear. But the sight distance is significantly reduced. Myopia is more common than hyperopia and astigmatism and is characteristic of occupational disease in humans is constantly working at the computer (so-called Computer Syndrome ).

There are several classifications of the disease eyes. One of them we have already mentioned: refractive   (the amplification refractive power of the cornea or lens) and axial   (changing the optical axis). Furthermore myopia, as well as other diseases, is divided into congenital   and purchased . When monitoring a patient in the dynamics of myopia is divided into progressive   and nonprogressive .

Farsightedness is the inverse properties. Instead of focusing on the retina, the light rays are collected in an imaginary point behind the retina, the retina appears to have a blurred image. Farsightedness, or as it is called, hypermetropia It has the same classification as myopia. However, unlike her person can see distant objects well, seeing everything in the vicinity of "blurred" form.

And finally, astigmatism   a situation in which different parts of the eye have different refractive power. That is, the light beams can not focus at a single point, as they are refracted at different ratio. Astigmatism may partly have the same properties as nearsightedness or farsightedness, depending on which way to change the refractive index.

To complete the coverage of this issue, we note another disease such as farsightedness age . The fact is that with age, the human eye loses its ability to accommodation that is fast setting sharpness of the image pickup objects in different contexts. As a result, close the eyes can not focus. Of course, although the age farsightedness and has similar features with the usual far-sightedness, is different from the name of a somewhat different nature of the disease. But do not mention it in this article would be a mistake.

Symptoms of nearsightedness, farsightedness and astigmatism

In principle, the main Symptoms of the diseases of the eye, we have already mentioned. So, the main symptoms of myopia is blurred vision at a great distance, the main symptoms of hyperopia - blurred perception of near objects, and astigmatism are characterized by symptoms of "floating" erratic vision.

Most often we see the deterioration of accident, when we can not read a book without glasses or vice versa, hardly distinguish driving up the number of transport. At this point, we can talk about what you have there is an eye disease that requires treatment. At the same time it is believed that some of the deviations from the norm are acceptable. For example, astigmatism, in which the difference of refractive powers in different parts make up one diopter, it is considered normal.

You quite able to define their own vision, using special tests with tables. Therefore we focus on the diagnosis of separately.

Diagnosis of refractive eye problems

The easiest and most common way of determining - tables . As you know, in these tables contain rows of letters of different sizes and a split ring, which is checked by the vision of people who do not know the alphabet. This test if done correctly determines nearsightedness or farsightedness on each eye separately.

All other methods of diagnosis more difficult. Instead of changing the size of the letters (i.e. the image) in some cases pick up additional correct lens which "returns" focus on the retina. By resorting to this method opticians in opticians, selecting appropriate points.

The other types of surveys, "studying" the elements of the eye, that is determined by the curvature of the cornea, pupil examination by precise lines in the expanded state and others.

Treatment of myopia, farsightedness and astigmatism

First of all, it should be understood that any of these three eye diseases is abnormalities in the shape or composition of the components of the eye. Therefore, drug therapy may have a short-term effect of improving and is purely preventive.

Thus, using atropine   or mezatona   You can expand the pupil which, of course, improve the clarity of vision. Thus, the application of pyracetam   or tsinozorina   dilates blood vessels, and improves circulation in the brain. But the positive effect goes with taking drugs. Vitamins allows you to remove minor symptoms of nearsightedness, farsightedness and astigmatism, but the complete cure, however.

The real action methods that can restore normal refraction correction involve violations. And of course, that we are talking about a correction, but not about the treatment of nearsightedness, farsightedness or astigmatism.

There are three methods of correction: spectacle . contact   and surgery . Points are assigned either in the early stages, or when more sophisticated methods are not applicable for one reason or another. Surgical correction is shown with a sharp worsening of the disease and its continuous progression.

Prevention of myopia, farsightedness and astigmatism

Myopia, hyperopia and astigmatism, in many cases could have been avoided if the patient follow certain simple rules. Their essence is reduced to the leveling action, threatening changes in optical instruments eyes, and exercises that strengthen these tools.

These exercises are quite simple and well known: fast switching focus from near objects for long, frequent blinking, the rotation of the eye, switching on the TV monitor or every 20 minutes be calm, not blinking objects.

If to add regular exercise control over their actions, that is read always with proper lighting and not lying, do not watch TV for hours on end, do not abuse addictions, protect eyes from damage, the problems with refraction can be avoided. Believe me, it's worth it, because apart from visual impairment can be a consequence of short-sightedness cataract And the disease is more dangerous.