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The eye performs the function of a high precision “camera with multifocal lenses”. When we look at an object, the rays of natural or artificial light are reflected on its surface, they pass the anterior part of the eye and are reflected by the system of eye lenses, then they get inside the eyebulb through the pupil and are focused in one point on the posterior pole of the eye, covered by the nervous tunic - the retina. Due to precise focusing a person gets a clear image.

Even refraction of the rays and clear focusing requires absolutely spherical and equilibrium optic refractive lenses (retina, lens). But something ideally even is very rare in nature. Thus, both the retina and the surface of the lens may have cavities or hills. If these changes in the surface are insignificant, they do not influence the visual acuity. If the irregularity exceeds specific critical values, it causes light dispersion.

Astigmatism is the pathology of the eye refraction, conditioned by uneven surface of the cornea or the lens. Due to this factor a person sees distorted shapes of objects, curved lines, and blurred images.

Most frequently astigmatism is linked to near-sightedness or far-sightedness.

Forms of astigmatism:

  • congenital;
  • acquired.

There is also physiological astigmatism which does not have any impact on visual quality. These are the values in the range of +/- 0.5 diopters, sometimes up to +/-1.0 diopters. At present precise detection of astigmatism, its type and degree is performed using computer diagnostics. Adequate selection of correction type is of utmost importance. Even slight mistakes may lead to the risk of intolerance of eyeglasses or lenses as well as further visual deterioration.

Correction methods:

  • correction with eyeglasses;
  • correction with contact lenses (hard, soft, Paragon night lenses);
  • refractive laser correction (LASEK, LASIK);
  • implantation of a toric artificial flexible lens.