Abstract: myopia has a certain genetic tendency, especially for high myopia. The heritability of both parents suffering from myopia is higher than that of one parent. But for general myopia, this tendency is not very obvious. The term
myopia is not new to us modern people. It refers to that when the human eye does not use adjustment, the external light is refracted through the refractive system of the eye and appears in front of the retina, which can not appear clearly in the macular region of the retina, resulting in unclear vision; The main manifestations of myopia are unclear distant objects and clear near objects.
development status of juvenile myopia in China
at present, 64.9% of the youth aged 7-18 in China are myopic, and 78.5% ~ 95.5% of college students suffer from myopia. China is a high incidence area of myopia, and the prevalence of juvenile myopia is increasing year by year, With the increasing pressure of entering school and the change of modern living habits (such as the popularization of electronic products) will also have a sustained impact on the prevalence of myopia. The decline of eyesight of primary and secondary school students is an important problem affecting the health of teenagers and related to the improvement of the health quality of the whole nation. Myopia is not only a medical problem, but also a social problem of common concern to the masses.
The causes of myopia are complex, and there is no clear conclusion so far. It is generally believed that it is related to the following factors:
1. Genetic quality: myopia has a certain genetic tendency, especially for high myopia. The heritability of both parents suffering from myopia is higher than that of one parent. But for general myopia, this tendency is not very obvious. Those with genetic factors had earlier onset age, mostly above 6.00D. But there are also high myopia without family history. High myopia belongs to autosomal recessive inheritance, and general myopia belongs to multifactorial genetic disease.
2. Developmental factors: infants are hyperopia due to their small eyeballs. With the increase of age, the eye axis gradually lengthens and develops normally until puberty. This is the emmetropia process of the eyes. For example, in this process, Due to the influence of various factors (such as light intensity, long time of close eye use, etc.), resulting in the eyes receiving various abnormal visual experience, or too much eye fatigue, which may lead to the overdevelopment of the eyeball and the growth of the eye axis, so as to develop in the direction of myopia, forming axial myopia or curvature myopia. This kind of myopia is called simple myopia, which usually starts in school age and is generally lower than 600 degrees. The development stops when they are about 18 ~ 20 years old. If it progresses quickly in childhood, it will progress more rapidly at the age of 15 ~ 20, and then slow down. This kind of myopia is often higher than 600 degrees, and can reach 2000 ~ 2500 or 3000 degrees. This kind of myopia is called high myopia or progressive myopia or pathological myopia. This kind of myopia can degenerate in old age, so vision can gradually decline, and glasses can not correct vision. However, very few are congenital and have myopia at birth.
3. Environmental factors: compared with genetic factors, scientists believe that environmental factors play a greater role in the occurrence of myopia. At present, studies have shown that long-term close eye use is a high-risk factor for the development of myopia. In addition, studies have shown that long enough outdoor exposure can prevent the occurrence of myopia. The intensity of visible light indirectly or directly affects the occurrence and development of myopia. Attention to eye environment and eye hygiene also play an important role in the prevention of myopia. Harm and influence of
1. Cause eye fatigue: due to unclear vision and enhanced eye regulation, eye muscles are in an excessive tension state for a long time, which is easy to cause eye fatigue. There may be eye swelling, eye pain, orbital pain, dizziness, nausea and other symptoms.
2. It is easy to cause strabismus: after myopia, due to the use of less adjustment and less collection, the function of internal rectus muscle is insufficient, and the collection function of both eyes is weakened accordingly. If it is not handled in time, it is very easy to cause exophoria or exotropia.
3. “Flying mosquito disease”: due to the liquefaction of the vitreous in the eye, the elasticity of the eyeball is reduced, which can produce floating objects in the vitreous, that is, vitreous turbidity, and black shadows such as dot, cobweb and filament flutter in front of the eyes, commonly known as “flying mosquito disease”. Usually “flying mosquito disease” does not affect vision, but more serious flying mosquito disease can affect vision.
4. Macular hemorrhage and degeneration: high myopia or pathological myopia is very easy to cause fundus lesions, which can cause macular hemorrhage, retinal and choroidal atrophy and degeneration, and seriously affect the vision of patients.
5. Retinal detachment: for high myopia, due to the elongation of the eye axis and the liquefaction and degeneration of the vitreous, the fiber cords in the vitreous can adhere to the retina and pull the retina. When the eyeball is impacted or injured by external forces, it can cause retinal rupture and retinal detachment. Retinal detachment is the most serious complication of high myopia, and the visual acuity is extremely reduced, Partial visual field defect, if not treated in time, can lead to blindness.
it should be emphasized that these eye diseases can occur not only in high myopia, but in all degrees of myopia. However, the risk increases with the deepening of myopia. Once permanent vision loss is caused, it will be very harmful, which will not only affect and damage the vision and visual function of individuals and families, It also brings a huge social and economic burden on global health care.