Nearsightedness, or myopia - is a problem with vision, in which people distinguish between parts of objects near the best.A more distant things look fuzzy and vague.In general, the farther away the object is, the worse it is seen by looking.This is a very common disease, according to statistics, about one billion people in the world suffer from this disease.
most common causes of myopia are:
- eyeball irregular shape, namely longer anteroposterior axis.In this case, the light rays reaching the eye are not converge on the retina, but in front of it.Moreover, such an elongated shape of the eyeball causes hyperextension of the fundus, which entails his degenerative changes (retinal detachment, etc..)
- Excess refraction of light rays by the lens, the cornea.In this case, the size of the eye are normal, but due to the stronger refraction of rays converge in front of the retina.
These were the immediate causes of myopia, but there are still a number of predisposing factors:
- Heredity.Experts believe that myopia is inherited not itself, namely a predisposition to it.The first risk group includes those who suffer from both parents to the problem.If the myopia is observed in only one of the parents, then the probability of the development of the child is about 30%.
- weakening of the scleral tissue.As a result, due to a significant intraocular pressure (18-24 mm. Hg. Art.) Hyperextension occurs eyeball, which contributes to myopia.
- weakness of accommodation, also leading to an increase in the eyeball.
- weakening of the whole organism: 1) disruption of the locomotor system;2) infectious diseases;3) an allergic reaction;4) birth trauma;5) traumatic brain injury;6) diseases nasopharynx and oropharynx;7) decreased immunity.
- poor working conditions of the body: 1) overvoltage eyes;2) reading in public transport, in the dark and lying;3) long-term work at the computer and watching television;4) lack of light;5) incorrect posture while reading and writing.
The earliest signs of myopia is blurred distant objects and flickering flies in front of the eyes.Is there an easy way to check your eyesight.This is not reading signs at a distance that is not an objective method.Go to a tree at a distance of about 10 meters.The tree must be a dense crown.A person with good eyesight can discern individual leaves.If the leaves are merged into a single mass, the problem occurs.
Expert opinion: This method is also subjective.From nesubektivnyh methods can distinguish visual acuity using computer diagnostics.
In ophthalmic practice myopia can be divided into three levels: mild, moderate, and high.Weak degree occurs in 82% of patients, the average - at 12% and the highest - 6%.Meaning of refraction at a low degree is not more than 3 diopters, with the average - from 3 to 6 and, finally, at a high - more than 6 diopters, and there are cases where this value reached 30. In addition to high myopia there is a malignant myopia, or severethe form.It is characterized by more rapid than in conventional forms, process development, and the emergence of numerous complications.Moreover, malignant associated with progressive myopia.This does not mean that the transition to a low degree or higher does not mean there may not be.However, this transition takes place slowly and at a low degree or even it can be the middle turn.If this is not possible malignant myopia.
Conservative correction methods, but not treatment of myopia are the glasses.Nowadays, many people prefer contact lenses.The main methods of treatment are:
- Laser correction
- Implantation of phakic lens
- Keratoplasty Radial keratotomy
- replacement lens or lensektomiya
Laser correction - this is the most common method today.The laser, acting on the cornea, makes it necessary to correct the patient's defect form.This procedure is performed on an outpatient basis and is able to correct myopia up to 15 diopters.The method is very accurate and secure.Modern devices are very sensitive to the slightest changes in your environment, so I just refuse to work in conditions that can damage the patient.Indications for the use of this method are unique: you need a full examination, take into account the age, individual characteristics.
lensektomiya applicable in cases of myopia up to 20 diopters.The essence of the method is to remove the damaged lens and putting in its place the artificial.Own lens is converted into an emulsion state and is removed through a microscopic orifice.This method is useful when the patient completely loses the ability to accommodation.The whole operation takes about 15 minutes, does not require a long hospital stay and suturing.
Unlike the previous method of installing fokichnyh lens is used when the patient has accommodation available.The essence of the method is that the patient's lens is left in place, and there is the implantation of the lens or in front or in the rear chamber of the eye.The most commonly used is the rear camera when the lens is installed behind the iris and in front of the lens directly.The operation is performed on an outpatient basis, does not require suturing.You can correct myopia up to 25 diopters.
Radial keratomas at one time was a real breakthrough.The method is to make the radial incisions in the cornea, which grow together, changing the shape of the cornea and improve vision.However, the method has a number of disadvantages: a long period of recovery, the inability to conduct operations at two eyes, complications.
Keratoplasty involves the use of a donor cornea.Its podsazhivayut cornea either before or in its thickness, or instead of it.
In any case, the use of a particular method depends on the clinic and the doctor's opportunities, the specific problems and the individual characteristics of the person.