What is astigmatism?


"Astigmatism is a form of refractive error (others include short sightedness or long sightedness). In astigmatism the front of the eye (the cornea) or the crystalline lens inside the eye does not have spherical surfaces, instead being a different curvature in one direction to another. To help visualise this, an astigmatic eye has curves like a rugby ball, and a normal eye has curves more like a soccer ball. As a result the eye is more shortsighted (or less longsighted) in one direction than another, and lines in some directions may be clear, but other directions blurry.
Astigmatism blurs things at all distances, and makes it harder for the eyes to focus accurately. Sometimes even small amounts of uncorrected astigmatism are associated with headaches or sore eyes during concentrated visual activity.
Astigmatism can be corrected by spectacles or contact lenses.
Irregular astigmatism sometimes occurs in conditions where the cornea (most commonly) or crystalline lens is warped or distorted. This may happen in conditions such as keratoconus or as a result of injury. Usually rigid contact lenses give better vision than glasses in cases of irregular astigmatism of the cornea."


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