Myopia occurs when the eyes focus optical power in front of the retina, and the best image of the object at a distance of 5 meters from the eye is not formed on the retina, and in front of her.
Myopia occurs when the refractive power of the optical media of the eye is too high for the length of the eye, or, conversely, the length of the eye is too small for the refractive power of the optical apparatus of the eye. Accommodation in this case does not help, since it can only increase the optical power of the media eye, rather than reduce it. The number of diopters, to which must be reduced by the refractive eye to the fact that he was emmetropic, determines the degree of myopia. With myopia, the further point clear vision of the subject is closer than 5 meters. Patients in need of an accommodation only at shorter distances, and patients whose degree of myopia up to three diopters do not need accommodation close distance 33 cm, which is working properly and near vision.
pathological (disease myopic)
lenticular (lenticular) myopia.
Physiologic myopia occurs when the mismatch of refractive power of optical media of the eye with a length of the eyeball. Usually this kind of myopia develops when the strong growth of the eyeball that occurs in 5-10 years. Sometimes physiological myopia may develop before the age of 25 years, although the physiological growth of the eyeball to the ends around age 18. Physiologic myopia is stationary and there does not lead to significant loss of visual acuity and the appearance of disability.
Lenticular lenticular myopia or refractive power is determined by the larger lens. Most often, this kind of myopia occurs when changes in lenticular nucleus, resulting in diabetes, and certain forms of congenital cataracts. Sometimes there is a drug lenticular myopia, and lens tissue injury due to taking certain medications (phenothiazine, gidrolazin, chlorthalidone).
Myopic disease occurs when the length of the eye is usually too large due to the growth front of the eyeball. Initially, this is a physiological myopia, but myopic disease process is not stabilized by any numbers of myopia and progresses continuously and the eyeball continues to grow. Myopic eyeball with the disease increased in size, the gap widened eye, the pupil is usually a wide, deep anterior chamber eye.
Patients with myopia complain weakening distance vision, which gradually increases. Often such patients are squint, as this area of the pupil decreases, reducing the scattering of light rays, and vision improved somewhat. The increase in the size of the eyeball causes a change in its structure. Increases the radius of curvature of the cornea.
If the cornea flattens unevenly - there is an additional visual impairment - astigmatism. If you have astigmatism, optical media of the eye there is no single focus, and image formation on the retina worsens. The sclera is stretched. Muscle of ciliary body is stretched and pulled to the periphery of the iris, which is manifested mydriasis (mydriasis). Accommodative ciliary muscle power decreases.
Disturbed nutrition lens and vitreous body, which can condition the appearance of lens opacity and the gradual development of destructive processes in the vitreous body. Later dystrophic processes in the choroid and retina, because these structures are limited in the growth of the eye and can not be stretched enough by increasing the size of the eye. Occurs eating disorders and optic nerve. Eating disorders and retinal stretching can lead to retinal detachment.
Treatment of myopia.
The problem of treatment of myopia - to stop or slow the progression of vision loss, to prevent complications of myopia. Patient is assigned restorative activities: daily routine, occupation therapy, physical therapy, adequate exposure to the outdoors. Should be avoided heavy exercise, sudden movements, jumps, lifts weights.
Visual mode of operation in which the work at close range should be as cut, lighting should be sufficient. Patients with mild to moderate degrees of myopia at work at close range every 15 minutes to give rest your eyes, look away, blink, do exercises for the eyes, patients with high degrees of myopia, such breaks should be done every 10 minutes.
Appointed by the calcium supplements and vitamins. It is recommended to eat foods rich in phosphorus. Foci of infection in the body must be subjected to rehabilitation. Correction of myopia with spectacles made using optics. Correction should be almost complete and provide binocular vision.
In most cases, to solve the problem of myopia in adults can be achieved by the operation of laser vision correction
With the steady progression of myopia degree assigned surgical treatment. Produced scleroplasty - strengthening of the posterior eyeball different biological materials or dosage keratorefractive operations.
Prevention of myopia should be carried out from early childhood. Children need to sit at work close up, lighting should be good. Working with similar items shall not be closer than 30 cm