Selection of glasses for myopia

In modern times, myopia is a fairly common problem in many people's eyesight.This disease according to statistics suffers four people out of ten.Myopia is a disease due to which a person badly distinguishes objects that are from him at a long distance.Myopia, also, is called myopia. It can be both congenital and acquired due to the influence of certain factors on the visual system.

What is myopia?

As a rule, myopia is caused by a violation of the optic system of the eye.The structure of the human eye includes the cornea and the lens.These anatomical elements of the human eye are designed to pass light rays, refracting them. During this, an image is formed on the retina of the eye, which then turns into nerve impulses and enters the human brain.To make the image clear it is necessary that its focus be exactly on the retina. This is how the human eye works, not suffering from myopia.

In the short-sighted person, the eye lengthens, as a result of which the retina recedes from the normal, stable location of the focus.

Because of the incorrect location of the focus, the image is focused not on the retina, but in front of it, so that the image appears blurry and fuzzy.As a rule, myopic eye reaches 30 mm, while a healthy eye has a size of 24 mm.

The cause of myopia may be different. The main ones are:

• heredity and physical predisposition;
• primary weakness of accommodation, which causes compensatory distension of the eyeball;
• weakening of scleral tissue, which leads to an increase in the size of the eyeball under the influence of high intraocular pressure;
• weakening of the body, due to incorrect nutrition, overwork or a number of diseases;
• visual work in adverse conditions, excessive eye strain (hours of computer work or sitting in front of the TV, poor lighting, reading in the wrong position, namely in the transport or in the recumbent position.

Diagnosis of myopia

As a rule, the degree of myopia is determined with the help of a negative lens. A negative lens, also, is called dissipative.Such a lens, as a rule, has edges thicker than the middle.The principle of the negative lens operation is that, after refraction, the rays diverge from the further point of clear vision, which lies ahead of the eye and coincides with the main focus of the lens.

The visual acuity of the myopic eye is always at a lower level, and the higher the degree of myopia, the lower this level. Correction of myopia is that the myopic eye regains complete visual acuity.

The main goal in determining myopia is to find such a negative lens, the back focus of which will fully coincide with the further point of clear vision of the myopic eye.

Preventive measures

It is desirable to prevent myopia from an early age, since any disease is always easier to prevent than cure.

To prevent the progression of myopia to short-sighted people, the following conditions must be adhered to:

• A patient with a high degree of myopia should read, write, draw, work with small subjects in limited quantities, no more than 4 hours a day.At the same time, it is necessary to regularly take breaks for rest. It is desirable for such a patient to choose a profession with the least load for the eyes at a close distance.
• A patient with a high degree of myopia should work under the most favorable conditions.Work in adverse conditions (for example, poor lighting of a room, work with small details) is fraught with serious complications.
• Complication of myopia can, also, cause the performance of heavy physical work or heavy physical exercises(for example, playing football, jumping, running, wrestling, etc.).
• With a weak degree of myopia, sports are not contraindicated, since it helps strengthen the body.But do not exercise heavy physical activity.
• It is desirable to work with myopia under daylight.
• Painful myopia should be prevented from excessive flow of blood to the head, namely, do not wash your head with excessively hot water, do not use alcohol, do not stay in hot, stuffy rooms, do not make sharp head inclinations and do not wear tight collars.

Principles of correction of myopia

To ensure effective myopia, the ophthalmologist is guided by the following principles:

• the degree of myopia is determined for each eye both in a stationary state and in motion;
• correction of vision is performed taking into account binocular vision;
• in the presence of myopia of weak and medium degree, it is required to restore the visual acuity as much as possible while working at close distances;
• In case the accommodation of the eyes weak myopia should be eliminated with the help of bifocals;
• the highest degree of myopia should be restored in full;
• the doctor can assign to the patient two pairs of glasses - for a distance and near. For the distance, the lenses should be slightly smaller (, ).

Efficiency of glasses

Points in the correction of myopia have a number of advantages. First of all, it is the ease of using this correction method and the absence of complications. In addition, glasses are the cheapest and safest method of correcting myopia.

However, glasses also have a significant drawback.With the help of vision glasses, a full optical system is not created, since they are at a certain distance from the eye.This factor is a significant obstacle to improving the visual acuity of the myopic eye.Therefore, in order to cure myopia, it is necessary to use more effective methods of treatment, for example, in the first place, surgical.

How is the selection of glasses

Picking up glasses with myopia gives more attention to lenses.The lenses are selected in accordance with the degree of myopia of a person.In order to do this before a short-sighted person, negative lenses are installed. The increase in visual acuity in this case testifies to the patient's short-sightedness.

As a rule, the selection of glasses begins with weak lenses, moving to stronger ones. This increases the visual acuity in the patient. The selection of lenses is carried out until the highest visual acuity is obtained.

In the event that the vision is noticeably improved with the help of two lenses, the weakest lens is chosen.This is done in order not to provoke the appearance of hypermetropia (farsightedness). In this case, the accommodation of the eye takes place to distinguish the signs of the table more clearly.As a result, the degree of myopia is determined by the weakest negative lens, through which the highest visual acuity is acquired.

Differences between myopia, hyperopia and normal vision

After selecting a lens for each eye, eyesight should be checked binocularly.The glass should be reduced by, 5 or, diopters.

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conclusions

The selection of glasses for vision is an important, responsible task for every ophthalmologist, since it is from his correct actions and calculations depends on how correctly the therapy of such eye disease will be performed, as myopia. After all, incorrectly selected glasses can lead to deterioration of visual acuity in the future, so thoroughness and thoughtfulness are important elements in the selection of glasses by an ophthalmologist.