Astigmatism

Astigmatism is a refraction error of the eye in which there is a difference in degree of refraction in different meridians. It is typically characterized by an aspherical cornea in which one axis of corneal steepness is greater than the perpendicular axis. Astigmatism causes difficulties in seeing fine detail, and can be often corrected by glasses with a cylindrical lens (i.e. a lens that has different radii of curvature in different planes), contact lenses, or refractive surgery.

Related Topics:
Refraction error - Eye - Refraction - Cornea - Glasses - Cylindrical - Lens - Contact lens - Refractive surgery

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Astigmatism occurs when either the cornea or the lens of the eye is not perfectly spherical. As a result, the eye has different focal points in different planes. For example, the image may be clearly focused on the retina in the horizontal plane, but in front of the retina in the vertical plane.

Related Topics:
Cornea - Lens - Eye - Retina

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In some cases vertical lines i.e. walls, may appear to the patient to be leaning over like the tower of Pisa.

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