![]() This type of refraction is called "astigmatism".Īs a result of the meridians or the same meridian of the corneal curvature is not consistent, it is not easy to correct with lenses. The refractive system of the eye is not completely positive spherical refraction, for example, under the pressure of the eyelid, the parallel light from the front of the eye cannot converge into a single focal point on the retina but a focal line. The disease is progressive. As the eyeball gradually lengthens and myopia diopter increases (generally above -6D), the pathological changes of the eyeball also gradually aggravated. With the myopia diopter below -10D, the degeneration of eyeball is not obvious, and can be corrected to normal vision by lens while with that above -10D, the ocular degeneration is obvious, and vision is not easy to correct to normal even with ordinary glasses or contact lenses. If there are complications, such cases may turn into low vision. Most cases happen on students, which develop slowly and is basically stable after the age of 20 with diopters below -6D. For most people, their eyes have no pathological changes and can be corrected to normal vision with appropriate lenses.Īlso known as pathological myopia, congenital myopia, high myopia, progressive myopia, malignant myopia, etc. ![]() When the refractive system of the eye is at ease, parallel light focuses in front of the retina, which is due to the anterior-posterior diameter lengthening of the eyeball or the strong refraction of the refractive system of the eye. It it possible to be caused by decreased refractive index of all refractive media in the eye, but this type is rare. ![]() Hyperopia can be caused by the flattening of any refractive surface of the eye, and most mainly caused by the flattening of the cornea. The eyeballs of highly hyperopia are usually smaller than those of emmetropia or myopia. For example, newborns are almost hyperopia. The short anterior-posterior axial shortening of the eyeball causes hyperopia. This type of refraction is called "hyperopia". This is due to anterior-posterior diameter shortening of the eyeball or the insufficient refraction of the eye. When the refractive system of the eye is at ease, the focus of the parallel light in front of the eye is behind the retina. There are many reasons for refractive errors, among which genetic factors are important. Of course, unreasonable use of the eye should not be ignored. Paying little attention to eye care is the same, such as reading or writing with improper postures, colse distance between the eye and the book, reading for a long time, reading while walking or in a moving car, which may cause eye fatigue and refractive errors.Īmetropia can be divided into the following types based on different symptoms: Thus, you should go to eye hospital as soon as possible.Īmetropia refers to refractive errors that the eyes are not able to focus light directly to form a clear image onto the retina without adjustment, and the image will be formed in front of or behind the retina. It includes myopia, hyperopia, and astigmatism. The first two signs are generally considered to be the symptoms of ametropia. If you don’t pay attention to them, you will have myopia or hyperopia for the latter two signs, it can almost be concluded that it is ametropia. If you have myopia, you will gradually appear to see distant things blurred, but it often doesn’t affect you to see near objects.Ĥ.The sign can also be exophthalmos or enophthalmos, which may affect your appearance. You have to squint when you see things in a distance. The main feature is that your visual acuity declines clearly after using eyes for a short time, and eye fatigue is easy to be caused. To some extent, adequate rest can relieve these symptoms.ģ.You may squint to see things far away or near. ![]() ![]() Using your eyes for a little longer, there are some symptoms of asthenopia (eye fatigue), such as sore or irritated eyes. Symptoms like double vision and watery eyes may also happen. Most of them can be gradually relieved after relaxation.Ģ.Sometimes you have blurred vision, and after a rest you may feel better. If you have any of the following signs, it's a warning showing that something may be wrong with your eyes:ġ.Your eyes are often dry and sore, and sometimes you even have the feeling of dizziness and nausea. ![]()
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