Astuteness

If you can see blurred both in the distance and in the vicinity, the cause can be a so-called astigmatism (astigmatism, Astuteness) be. The eye can no longer focus the incident light on an exact point on the retina and thus focus, but rather see points as blurred lines.
Normally, the cornea of ​​the eye is almost spherical in the horizontal and vertical directions, so that both the light coming from the side and the light from the front reach the eye. However, if this natural corneal curvature deviates from its normal shape in astigmatism, the refractive power of the eye changes.

Definition of astigmatism

As astigmatism is by definition an ametropia of the eye called the caused by an astigmatism is. The one so crooked Cornea causes one Image errors in the optics of the eyeso that, depending on the degree of astigmatism, this results in blurred vision near and far.

The word "astigmatism" has its origins in Greek and means translated "Pointlessness". Due to the curvature of the cornea, incident light rays do not hit the in a single point Retina, but line or rod-shaped (hence the German term "Stabsichtigkeit").

Forms of astuteness

Depending on the type of astigmatism, a distinction is made between different forms:

• Regular astigmatism (regular astuteness):

The Astigmatism then referred to when a unequal refractive power in two mutually perpendicular planes (Meridians) is present.

- If the refractive power in the vertical plane is stronger than in the horizontal plane, one speaks of Astigmatism according to the rule.

- If the refractive power in the horizontal plane is stronger than in the vertical plane, one speaks of Astigmatism against the rule.

• Irregular astigmatism (irregular astuteness):

Irregular astigmatism is when the The refractive power at different points of the cornea differs greatly.

causes

A Clarity of the eye is caused by the astigmatism of the eye, which different causes may have. In rare cases, astigmatism is not only due to the Cornea of the eye, but also in other parts of the eye that also contribute to the refractive power of the eye (e.g. the Lens of the eye).

Regular astigmatism

Mostly this is the cause of a regular astigmatism Inheritance. Those affected have seen her since birth a crooked cornea and thus the typical regular or regular astigmatism arises. In this form the Refractive power in two mutually perpendicular planes differently pronounced. According to science, this form of astigmatism changes only insignificantly in the course of life.

Irregular astigmatism

An astigmatism with irregular Astigmatism and thus the irregularly distributed refractive power of the eye is called irregular astigmatism. The causes for this can be Corneal scars or corneal ulcers so that the refractive power is very different due to the different curvatures of the cornea of ​​the eye in different places. Irregular astigmatism is also possible, however, as a result of an irregularly curved or clouded lens, for example in the cataract (grey star).

Irregular astigmatism can also result from a so-called Keratoconus occur. This is a malformation of the cornea, leaving the cornea in the middle conical outwards grows. So it happens again and again necessary operations and the Cornea becomes increasingly thin and scarred as the disease progresses.

Irregular astigmatism can also result from surgical interventions that temporarily involve a Scarring of the cornea of the eye occurs, but regresses again. This is for example after an operation of the green stars (glaucoma) or des cataracts (Cataract) the case.

Symptoms

The symptoms of astigmatism (astigmatism, astigmatism) depend on the Strength of the curvature the cornea from, as from this different degrees of refractive error surrender. A slight astigmatism is often used by those affected not noticed at all.

However, if the corneal curvature is more pronounced, the clear astigmatism fails blurred vision near and far on. The eye continuously tries to bring the distorted image back into focus by adjusting the refractive power (accommodation), which, however, leads to headaches and burning eyes if the vision is very strong. The astuteness can occur alone, but there is often an additional one myopia (Myopia), Farsightedness (Hyperopia) or Presbyopia (Presbyopia), which additionally increase the visual difficulties.

diagnosis

To one astigmatism be determined special devices used. The ophthalmologist can do the exact thing with it Degree of ametropia determine. One of the devices is called Ophthalmometer and is used to measure astigmatism corneal curvature. It is made by the ophthalmologist Radius of curvature in each plane measured and based on this Evaluate the power of the planes determined. As with nearsightedness, farsightedness and presbyopia, asthma is also in Diopters specified. The axis in which the curvature lies is also specified. This information is given in Angular degree.

therapy

As with other ametropia of the eye, there are various options for treating astigmatism. Besides the Correction of astuteness with glasses or contact lenses is the operative intervention a possible therapy. When choosing the appropriate therapy is crucial to what form of astigmatism it is (regular or irregular) and how pronounced the astigmatism is.

With children in particular, it is extremely important that therapy is started early, as the children would otherwise permanent deterioration in eyesight develop. For this reason, too, it is advisable to take the children to the ophthalmologist at an early stage. Especially when the Parents themselves have an astigmatism to have.

Of the regular astigmatism hardly changes and therapy is done by correcting with glasses that specially cut cylinder glasses Has. Also are dimensionally stable (fixed) contact lenses suitable for correcting regular astigmatism. When choosing contact lenses, it is important to know that Wearing breaks to protect yourself and to have an adequate supply of nutrients and oxygen are just as necessary as adequate hygiene.

Of the irregular astigmatism is characterized by an irregular curvature of the cornea and not correctable through glasses. In this case, a fixed contact lens can significantly improve eyesight; the so-called one is an alternative Keratoplasty (Corneal transplant) as a possibility.

A treatment of astuteness using is generally also possible laser, with the same restrictions as for nearsightedness (myopia). Every surgical procedure on the eye has as a possible one Complication is complete loss of the eye or visionwhat should be carefully considered when making a decision. Especially with pronounced astigmatism, it is not possible, one postoperative normal vision to reach.

For more information, see: Laser therapy for astigmatism

course

While regular astigmatism (Astigmatism, Astigmatism) does not normally change in the course of life, irregular astigmatism can progress steadily. This is especially the case if there is a permanent malformation of the cornea, in the case of the center of the cornea grows conically forward (so-called keratoconus).

If the astigmatism is not corrected, severe headaches must be expected, as the eye tries to focus independently on the incorrectly seen image, but this fails.

Prevention

An astuteness can NOT prevented become. However, a Progression or development of accompanying symptoms how headaches in children can be avoided by correcting astigmatism early with glasses.