{"id":2152,"date":"2020-03-30T19:54:34","date_gmt":"2020-03-30T19:54:34","guid":{"rendered":"https:\/\/imedicalsociety.org\/?p=2152"},"modified":"2020-03-30T19:54:34","modified_gmt":"2020-03-30T19:54:34","slug":"astigmatism","status":"publish","type":"post","link":"https:\/\/imedicalsociety.org\/astigmatism\/","title":{"rendered":"Astigmatism: signs, diagnosis, treatment"},"content":{"rendered":"
In astigmatism<\/strong>, an irregular shape of the cornea of the eye causes the incident light to be imaged distorted on the retina (Source<\/a>). As a result, the patients affected with this condition have their vision blurred (Source<\/a>). There are many causes of astigmatism (Sources<\/a>), but it is often congenital (Source<\/a>). It can often be corrected with special visual aids (Source<\/a>) of different types (Source<\/a>). Read more about astigmatism.<\/p>\n<\/div>\n<\/div>\n ICD codes for this condition are H18 <\/span>H52<\/span><\/span><\/p>\n The cornea is the foremost part of the eyeball that lies in front of the pupil. It is slightly oval in shape, slightly smaller than a small coin, and about half a millimeter thick (Source<\/a>). Since it rests on the round eyeball, it is itself spherically curved, much like a contact lens.<\/p>\n We speak of astigmatism (inaccurately: “corneal curvature”) when the cornea is not evenly curved. This anomaly is called “astigmatism”.<\/p>\n Normally, the cornea, together with the lens of the eye, ensures that the parallel incident rays of light are bundled and focused on a single point on the retina (focal point). This enables sharp vision.<\/p>\n In astigmatism, however, the cornea is unevenly curved, which means that the light cannot be properly focused. In some places, incoming light rays are bundled more strongly than in others. As a result, they do not merge into a single point on the retina: no single clear point is imaged on the retina – vision is blurred.<\/p>\n In regular astigmatism, incident light rays are imaged on vertical focal lines (“rod”). This form of astigmatism can be further subdivided, but it is mainly relevant for the optician to be able to produce a perfectly fitting visual aid.<\/p>\n Irregular is a curvature of the cornea whose optical planes are not perpendicular to each other. To put it more simply: While there is still a certain order in regular astigmatism, an irregular astigmatism sometimes has no recognizable system at all. In extreme forms, such as corneal scarring, the light is deflected in various directions so that there are hardly any focal lines left. The treatment of irregular astigmatism is therefore more difficult.<\/p>\n Astigmatism can also be judged by where the focal lines lie in relation to the retina. Often one is in the retinal plane, but the other is in front of it (astigmatism myopicus simplex) or behind it (astigmatism hyperopicus simplex). There can also be a focal line in front of it and the other one behind it (astigmatism mixtus). Sometimes there is farsightedness or nearsightedness (hyperopia or myopia) in addition to astigmatism: “Astigmatism compositus” is what the specialist calls this.<\/p>\n Many patients primarily complain of headaches and eye pain with slight astigmatism. In contrast, symptoms of impaired vision often appear later<\/a> or not at all. This is because the eye is constantly trying to correct the blurred image by changing the shape of the lens, which in the long run strains certain eye muscles<\/a>, eventually resulting in headaches and eye irritation.<\/p>\n When vision problems occur, the environment not only appears blurred to those affected, but usually also distorted. Because there is no focal point on the retina, but rather focal lines, they tend to see punctiform structures as stripes or rods. This also explains the term “astigmatism”.<\/p>\n If it is more pronounced, congenital astigmatism in children leads to a so-called weakness of vision (amblyopia) if left untreated. In medicine, this is the name given to a visual impairment that occurs because vision is not properly “learned”. Since a sharp image never falls on the retina, no correct sensory perception can be transmitted via the optic nerve to the brain, where the data is processed. If a congenital visual defect lasts too long, the brain adjusts to it and then makes normal vision impossible, even if the actual visual defect is eventually corrected.<\/p>\n<\/section>\nDescription<\/strong><\/h2>\n
What is astigmatism?<\/h3>\n
What types of astigmatism are there?<\/h3>\n
\u00a0Corneal Curvature Symptoms<\/span><\/h2>\n<\/section>\n
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