Astigmatism

General characteristic of a disease

The astigmatism is an inborn inability of eyes to the correct focusing of sight. Normal the light beam has to be focused on a retina. At an astigmatism of eyes instead of one focused point, are formed several, and image looks a little indistinct.

Inborn discrepancy of force of section of a cornea of an eye and retina is the reason of this type of an ametropia (the imperfect refracting eye force). The astigmatism of eyes quite often accompanies other types of an ametropia of sight – far-sightedness and short-sightedness. The name of a disease comes from the Greek term "stigma" (point).

Except indistinct vision of objects patients with an astigmatism of eyes usually complain of a headache and bystry fatigue of eyes. Brings a systematic overstrain of oculomotor muscles to them during the visual work. It is considered that approximately the sixth part of the population of the planet suffers from an astigmatism of different degree of manifestation.

Types of an astigmatism

Expressiveness of an astigmatism depends on a difference between two main meridians of an eye. The focal line between back and front focus of an eye is longer, the visual acuity is worse. Most often this pathology is caused by an abnormal toric structure of a cornea. Such type of an astigmatism, respectively, is called a corneal astigmatism.

The astigmatism, in turn happens, direct, the return or to slanting axes depending on an arrangement of meridians down, horizontals or on the slanting line.

There is also a classification of types of an astigmatism of eyes depending on an arrangement of focuses concerning a retina:

• The astigmatism is called difficult short-sighted at the main focuses with localization before a retina.
• If one focus is before a retina, and another directly behind it, the astigmatism of eyes is considered a simple short-sighted type of an ametropia.
• The mixed far-sighted astigmatism is formed at front focus before a retina and the back focus located behind it.
• The difficult far-sighted astigmatism is diagnosed at an arrangement of both focuses behind a retina.

The most rare form of a disease - the acquired astigmatism of eyes. It is formed as a result of an injury, a serious ophthalmologic disease or badly performed operation in the eyes. At this form of the ametropia called wrong the main meridians are not allocated that significantly complicates treatment of an astigmatism.

Diagnosis of an astigmatism of eyes

Despite the fact that the astigmatism, as a rule, is inborn it is diagnosed most often on the second year of human life. At this age the doctor is able to make the forecast of further development of system of organs of sight in the child.

In diagnosis of an astigmatism survey of an eyeground, check of visual acuity by means of tables, and also a skiaskopiya or shadow test is applied. By means of the last the eye refraction is checked.

Refractometry is able to define more precision measurement of extent of distortion. The procedure is completely automated, painless for the patient and allows by means of the special computer equipment with the maximum accuracy to measure the optical power of an eye at an astigmatism.

Treatment of an astigmatism

Treatment of an astigmatism of eyes is possible in several ways. Optical correction of sight at an astigmatism assumes use of points or contact lenses. Points – the simplest and economical method of treatment of an astigmatism of eyes, however it has a number of shortcomings: restriction of side sight, disturbance of space perception, discomfort when carrying, etc.

Contact lenses – more comfortable method of correction of an astigmatism of eyes. And still their use is connected with certain inconveniences too. This feeling of a foreign body in an eye, probability of infection or traumatizing an eye.

Also surgical treatment of an astigmatism of eyes is possible. The most radical operation at an astigmatism is an astigmatic keratotomy or joint stock company. During it on perimeter of a cornea of the patient several deep cuts are made. They allow to change curvature of a cornea. This type of operation at an astigmatism is applied at patients with sight coefficient below 2D. It significantly concedes to efficiency of laser technologies.

The similar procedure with change of curvature of a cornea can be carried out by means of the laser, deleting with it layers of tissues of eye. This type of operation at an astigmatism is less traumatic, however and after it the patient needs the long period of recovery.

The most effective among operations at an astigmatism the technique of a laser keratomilez is considered. Its essence in creation of a new lens under a cornea blanket. Laser operations at an astigmatism of LASIK and REIK can be carried out already at early children's age at bad portability of optical treatment of an astigmatism.

Prevention and treatment of an astigmatism at children

The out-of-focus image at an astigmatism at children can serve as the reason of oppression of visual system and the distorted perception of visual objects. It secondary decrease in visual acuity, development of an amblyopia (a lazy eye) results, from squint – and other complications of an astigmatism at children.

It is possible to warn similar diseases by means of timely physiotherapeutic, optical, and in rare instances, and surgical treatment of an astigmatism of eyes. The early beginning of therapy allows to improve in most cases significantly visual acuity, and over time and to get rid of-point dependence.

However it is important to remember that conservative therapy is only capable to improve work of an eye and to a certain extent to compensate refraction shortcomings. At high degree of an astigmatism at children it is possible to eliminate defect of a cornea only by means of surgical techniques.