The word "astigmatism" is from the Greek "stigme", which means a point, and
According to eye specialists, almost all the inhabitants of the planet have some degree of astigmatism, but for the majority of people (85%) is characterized by its small size (up to 1 diopter), has no effect on visual acuity. At the same time about 15% of the population in need of correction of astigmatism with special points (or lenses) or surgery.
Astigmatism may suffer both adults and children.
In most cases, astigmatism is hereditary and is called innate. Acquired astigmatism usually develops
What's going on?
Astigmatism occurs in the case of irregularly shaped lens optical system of the eye. Most often, the problem is an uneven curvature of the cornea, at least — in the lens.
Normally cornea has a spherical shape, that is, its refractive power in the vertical and horizontal planes are the same. In astigmatism refractive power of the cornea to these planes are different, for example, the cornea refracts more vertically than horizontally. As a result, a person sees the objects blurred or distorted regardless of where they are located.
Astigmatism is long-sighted, short-sighted and even mix: one axis sighted, on the other — short-sighted.
A small degree of astigmatism man simply does not notice. Getting used to see things in a slightly blurred (or extended) form, he does not even know about problems with his vision. Smell a rat astigmatik can only frequent headaches and fatigue increased load on the eye — for example, after
If astigmatism left untreated, it can lead to squint and a sharp drop in sight.
The diagnosis is established astigmatism eye doctor after examining the patient's visual acuity with special tables and determining the difference in the curvature of the cornea — to this end, using special cylindrical lens.
A person suffering from astigmatism prescriptionglasses will contain a mysterious letter: sph (sphere), cyl (cylinder) and ax (axis). Sphere indicates the amount of spherical astigmatism and the cylinder axis, and — the size and orientation. These glasses patients often referred to as "complex", and doctors — cylindrical.
To date, there are three ways to correct astigmatism glasses, contact lenses and surgery.
Glasses and contact lenses for astigmatism are chosen strictly individually. Cylindrical lenses if necessary, can be combined with lenses for the correction of nearsightedness or farsightedness. Unfortunately, with a high degree of astigmatism glasses tolerated bad: people are beginning to hurt my eyes and feel dizzy.
It is important that after the appointment of glasses patients constantly observed by an ophthalmologist for the timely replacement with a stronger or weaker.
Glasses and contact lenses do not cure astigmatism, they only correct vision. Completely rid of astigmatism can only use the surgery. In currently used for this purpose:
- Keratotomy — the application of non-through cuts in the cornea to reduce refraction enhanced axis. This operation is used for myopic or mixed astigmatism.
- Termokeratokoagulyatsiya — cauterization of the peripheral zone of the cornea heated metal needle with the curvature of the cornea is increased, and thus increases its refractive power. The operation is performed for presbyopia correction of astigmatism.
- Laser photocoagulation — differs from previous methods in that the metal tip is used instead of the laser beam.
- In recent years, for correcting astigmatism has been applied an excimer laser. The therapeutic effect is achieved by evaporation of the excimer laser with the corneal surface layer of predetermined thickness.