Astigmatism

It is a refractive error caused by the irregular curvature of the cornea or (less often), the lens. The curvature and thereby also the refractive properties of the cornea or the pupil differ on different axis and as such the eye does not focus light evenly on the retina. This results in distorted or blurred vison at all distances. This problem usually starts in childhood and is often accompanied by one of the basic errors – long or short-sightedness. It is corrected using cylindrical glasses or toric contact lenses. A certain lower degree of astigmatism is physiological (the cornea is almost never absolutely perfectly curved) and as such does not require optical correction. Astigmatism may be corrected using a refractive laser procedure or through incisions made into the cornea (astigmatic keratotomy). When implanting phakic lens or when performing refractive lens exchange (RLE, PRELEX) it is possible to use an artificial toric intraocular lens.