Abstract: most myopia occurs in adolescents. The degree deepens year by year in the stage of development and growth, and does not develop or develops slowly after maturity. The degree of myopia rarely exceeds 6D, there is no degenerative change in the fundus, and the vision can be corrected with glasses, which is called simple myopia., Myopia Myopia is a symptom that the eyes can’t see far objects but can see near objects. On the premise of static refraction, distant objects can’t converge in the retina, but form a focus in front of the retina, resulting in visual deformation and blurring of distant objects. Myopia can be divided into refraction and axial myopia. Among them, refractive myopia is the most serious. Refractive myopia can reach more than 600 degrees, i.e. height Myopia., Myopia refers to a refractive state in which the focus falls in front of the [2] retina after the parallel light is bent through the refractive system of the eye without adjustment. Therefore, myopia can not see the distant target. If the target is gradually moved closer to the eye and the light emitted is scattered to a certain extent, the focus will move backward. When the target moves closer to a certain point in front of the eye. The closer this point is to the eye, the deeper the degree of myopia., , Most of the causes of myopia are the long anterior and posterior axis of the eye (called axial myopia), followed by the strong refractive power of the eye (called refractive myopia). Myopia mostly occurs in adolescence, and genetic factors have a certain impact, but its occurrence and development are closely related to insufficient lighting, improper reading posture, long-distance work, etc. Most myopia occurs in adolescents, and the degree deepens year by year in the stage of development and growth, and does not develop or develops slowly after maturity. Its The degree of myopia rarely exceeds 6D, there is no degenerative change in the fundus, and the vision can be corrected with glasses, which is called simple myopia. Another kind of myopia occurs earlier (it can occur between the ages of 5 and 10), and the progress is very fast. It continues to develop after the age of 25. The degree of myopia can reach more than 15d, often accompanied by fundus changes, and the vision is not easy to correct, which is called degenerative myopia. In addition, it is customary to call myopia below 3D as mild myopia, those between 3 and 6D as moderate myopia, and those above 6D as high myopia. Mild or moderate myopia, except for blurred distant objects In addition, there are no other symptoms. When working at a close distance, you can see small targets clearly without adjusting or using less adjustment, but feel convenient. However, when working in high myopia, the target distance is very close, and the two eyes are too inward, which will cause excessive use of internal rectus muscle and visual fatigue., The anterior chamber of high myopia is deep, the pupil is large, and the eyeball is slightly prominent due to the length of the anterior and posterior axis. White or gray crescent shaped spots can be seen on the temporal side of the optic disc, which is called myopic semilunar spots. This is because the sclera extends backward, the retinal pigment epithelium and choroid are separated from the temporal edge of the optic disc, exposing the sclera or part of the choroid and sclera. The posterior pole sclera continues to expand backward, knee crack like stripes and subretinal neovascularization can appear in the macula, and plaque atrophy and degeneration of the nearby retina and choroid can lead to posterior scleral staphyloma. There is often hyperpigmentation and even bleeding in the macula, Formation of atrophic spots (Forster fuchspot) thus seriously damages vision. Macular disease with high myopia has become one of the main causes of blindness. Such patients are often accompanied by vitreous liquefaction and turbidity, and a few can also have retinal detachment and complicated cataract. Mild and moderate myopia has no special changes in the eyes, but there are also myopic semilunar spots and leopard shaped fundus changes. Myopia can be cured over time It leads to collective dysfunction and exotropia.,
myopia Myopia is a symptom that the eyes can’t see far objects but can see near objects. On the premise of static refraction, distant objects can’t converge in the retina, but form a focus in front of the retina, resulting in visual deformation and blurring of distant objects. Myopia can be divided into refraction and axial myopia. Among them, refractive myopia is the most serious. Refractive myopia can reach more than 600 degrees, i.e. height Myopia.
myopia refers to a refractive state in which the focus falls in front of the [2] retina after the parallel light passes through the refractive system of the eye without adjustment. Therefore, myopia can not see the distant target. If the target is gradually moved closer to the eye and the light emitted is scattered to a certain extent, the focus will move backward. When the target moves closer to a certain point in front of the eye. The closer this point is to the eye, the deeper the degree of myopia.
myopia mostly occurs because the anterior and posterior axis of the eye is too long (called axial myopia), followed by the strong refractive power of the eye (called refractive myopia). Myopia mostly occurs in adolescence, and genetic factors have a certain influence, but its occurrence and development are closely related to insufficient lighting, improper reading posture, long-distance work, etc.
Most myopia occurs in adolescents. The degree of myopia deepens year by year in the stage of development and growth, and does not develop or develops slowly after maturity. The degree of myopia rarely exceeds 6D, there is no degenerative change in the fundus, and the vision can be corrected with glasses, which is called simple myopia. Another kind of myopia occurs earlier (between 5 and 10 years old) and progresses rapidly. It continues to develop after the age of 25. The degree of myopia can reach more than 15d, often accompanied by fundus changes, and vision is not easy to correct, which is called degenerative myopia. In addition, it is customary to call myopia below 3D as mild myopia, those from 3 to 6D as moderate myopia, and those above 6D as high myopia.
Mild or moderate myopia has no other symptoms except blurred distant objects. When working at a close distance, you can see small targets clearly without adjusting or using less adjustment, but feel convenient. However, when working in high myopia, the target distance is very close, and the two eyes are too inward, which will cause excessive use of internal rectus muscle and visual fatigue.
high myopia has deep anterior chamber, large pupil and slightly prominent eyeball due to the length of anterior and posterior axis. White or gray crescent shaped spots can be seen on the temporal side of the optic disc, which is called myopic semilunar spots. This is because the sclera extends backward, the retinal pigment epithelium and choroid are separated from the temporal edge of the optic disc, exposing the sclera or part of the choroid and sclera. The posterior pole sclera continues to expand backward, knee crack like stripes and subretinal neovascularization can appear in the macula, and plaque atrophy and degeneration of the nearby retina and choroid can lead to posterior scleral staphyloma. The macula often has pigment hyperplasia, even bleeding, forming atrophic spots (FORSTER fuchspot), which seriously damages vision. Macular disease with high myopia has become one of the main causes of blindness. Such patients are often accompanied by vitreous liquefaction and turbidity, and a few can also have retinal detachment and complicated cataract. Mild and moderate myopia, no special changes in the eyes, but occasionally myopia, semilunar spot and leopard shaped fundus changes. Myopia over time can lead to collective dysfunction and exotropia.
myopia is caused by many factors. In recent years, many evidences show that environmental and genetic factors are involved in the occurrence of myopia: external factors – looking at things closely for a long time, It causes the ciliary muscle in the eye to lose the elastic lens, resulting in the inability of the lens to recover (thicker than natural), so myopia occurs.
Genetic factors: the incidence rate of myopia in the next generation is high in the two parent families with high myopia. The myopia has a certain genetic tendency and has been recognized. However, the genetic tendency of general myopia is not very obvious.
environmental factors: the occurrence and development of myopia are closely related to close eye use. Teenagers’ eyeballs are in the stage of growth and development, with strong adjustment ability and large extension of eyeball wall. When reading, writing and other close work, they not only need to play the role of eye adjustment, but also need the cohesion of both eyeballs. In this way, the extraocular muscles exert a certain pressure on the eyeball. Over time, the front and rear axes of the eyeball may become longer. Every 1 mm increase is – 3. 00 diopter (that is, 300 degrees in general). Of course, the vast majority of this myopia is simple myopia. Generally, the diopters are relatively low, all below 6 diopters. The onset is mostly before and after puberty, and the progress is relatively slow. Some people call this myopia true myopia to distinguish it from pseudomyopia.