How does an astigmatism on vision?
The transparent cornea is placed at the forefront of the eye and allows light to enter the eyeball. The cornea performs approximately ¾ of the work that is needed for clear vision, by collecting the light beams and zulenkt to a point.
The lens, located behind the cornea in the eye completes the work and directs the light beam focused onto the retina, and in a very specific point: the fovea, the place - the place of sharpest vision. If the light is not concentrated at a single point in the fovea, the image produced on the retina are not relayed properly to the brain become a game tester.
If astigmatism is present, the surface of the cornea is curved unevenly and not spherical. The cornea so the light can not combine into a single point, as it is necessary for a sharp image. There are usually two mutually perpendicular meridians, each having its own focus, with smooth transitions between them. Therefore, never caused a sharp image, no matter where the viewer hinschaut.
Who gets astigmatism?
Astigmatism is very common (who is already built perfectly?). Experts believe that almost everyone has some degree of astigmatism, often at birth, which remains the same throughout life. Of interest to parents and people who work with children, could be that the astigmatism affects often on school performance, but is not found on school vision screenings.