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近视眼是指在无调节状态下平行光线经眼屈光系统屈折后，成像在在视网膜前，使远距离物体不能清晰地在视网膜上成像。近视眼看远模糊，看近清晰。 近视眼按近视程度分：轻度近视眼：小于300度,中度近视眼：300-600度,高度近视眼：大于600度。 按病变性质分：单纯性近视眼：一般小于600度，病理性近视眼：进行性，伴有眼底改变。 按屈光成分分：曲率性近视眼：由于角膜或晶状体表面弯曲度近强所致；屈光率性近视眼：由于屈光介质的屈光率过高所引起；轴性近视眼：是由眼球前后轴过度发展所致，大多数近视眼系轴性近视眼。 按动态屈光分：真性近视眼在静态屈光情况下仍为近视眼，绝大多数近视眼为真性近视眼，大部分近视其屈光在600度范围内。 近视和近视眼是一样的吗？回答：不一样。 近视是视力概念：目光短浅而已。远视力低常，近视力正常。 近视眼是屈光概念，指一类近视性屈光不正。以眼的屈光学诊断为准。 近视眼必定近视，但近视并非一定是近视眼。 myopia Main Entry: my·o·pia Pronunciation: \mī-ˈō-pē-ə\ Function: noun Etymology: New Latin, from Greek myōpia, from myōp-, myōps Date: circa 1752 1 : a condition in which the visual images come to a focus in front of the retina of the eye resulting especially in defective vision of distant objects 2 : a lack of foresight or discernment : a narrow view of something — my·o·pic \-ˈō-pik, -ˈä-\ adjective — my·o·pi·cal·ly \-pi-k(ə-)lē\ adverb Nearsightedness, or myopia, as it is medically termed, is a vision condition in which near objects are seen clearly, but distant objects do not come into proper focus. Nearsightedness occurs if your eyeball is too long or the cornea has too much curvature, so the light entering your eye is not focused correctly. Nearsightedness is a very common vision condition that affects nearly 30 percent of the U.S. population. Some evidence supports the theory that nearsightedness is hereditary. There is also growing evidence that nearsightedness may be caused by the stress of too much close vision work. It normally first occurs in school-age children. Because the eye continues to grow during childhood, Nearsightedness generally develops before age 20. A sign of Nearsightedness is difficulty seeing distant objects like a movie or TV screen or chalkboard. A comprehensive optometric examination will include testing for Nearsightedness . Your optometrist can prescribe eyeglasses or contact lenses to optically correct Nearsightedness by altering the way the light images enter your eyes. You may only need to wear them for certain activities, like watching TV or a movie or driving a car, or they may need to be worn for all activities. Refractive surgery or laser procedures are also possible treatments for Nearsightedness as is orthokeratology. Orthokeratology (ortho-k) is a non-invasive procedure that involves the wearing of a series of specially-designed rigid contact lenses to progressively reshape the curvature of the cornea over time. |
