How is the myopia caused

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asked in Ophthalmology by myopia
How is the myopia caused

3 Answers

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answered by anonymous
First, the cause of the disease
The cause of myopia is still not unified, but it comes down to the two major factors of heredity and environment. Human visual organs vary and evolve to adapt to the constant changes of the external light. The effects of genetics and environment on the eye are described as follows.
1. genetic factors (hereditary factor)
According to the group survey, it has been proved that the incidence of myopia is very different among ethnic groups, and the Asians are mostly myopia with Chinese and Japanese. European Jews are more common than the myopia of native people in Britain, Germany and other countries. Stephoson investigated the diopter of the eyes of children in London in 1919. The myopia of Jewish children was about 10 times more than that of local children.
(1) high myopia:
Hu Danning on the 61 family survey found that: parents have myopia, 12 offspring per capita for high myopia (100%); the parents of high myopia, and the incidence of their offspring (another indication of the parents were heterozygous), 40 children in 23 high myopia (57.5%), and the incidence rate of expected (50%) compared to P>0.05; the parents showed normal offspring of 25 family illness (indicating parents were heterozygous), 197 children in 68 cases, by using Winburg and Lenz correction method, the incidence rates were 21.3% and 22.2%. Compared with the expected 25% P>0.05. These three conforms to the autosomal recessive inheritance law, but can be affected by environmental factors to reduce the degree of expression or not. People with high myopia, such as those with normal phenotype, have 18% to 24% opportunities to marry with heterozygotes and have the potential to produce children with high myopia. Therefore, it is better to believe that high myopia in China is an autosomal recessive inheritance.
(2) simple myopia:
That is, low and moderate myopia, which refers to myopia or myopia astigmatism below 6.0D. Generally, there is no obvious change in the fundus, and the corrected visual acuity is normal. It is the most common type of ametropia. In the twin study, no matter the rate of myopia consistency or diopter difference is the same degree of the same egg than that of the ovum, statistical treatment has a significant meaning, suggesting that genetic factors play an important role in the occurrence of myopia. According to the correlation coefficient of the group, the myopia heritability was 61%. The genetic index was 65%. The genetic index of the ocular axis, the radius of curvature of the cornea and the depth of anterior chamber were 55.5%, 49.1%, 72.1% respectively. A survey of first degree relatives in Shanghai high school students calculated the heritability of 50.5%, that is, about half of the incidence of myopia in heredity and environment. Therefore, it is deduced that simple myopia is a multifactor inheritance.
In summary, the high myopia is an autosomal recessive inheritance, and the general myopia is a multifactor inheritance, which obeys both the genetic rule and the participation of environmental factors.
2. environmental factors (environmental factor)
Certain environmental factors can increase ocular accommodation, form a certain degree of refractive myopia, and make eye axis longer, forming axial myopia. Duke-Elder's ophthalmology textbooks have reported examples of young animals raised in cages to increase myopia than wild ones. In recent years, foreign and domestic scholars have been feeding young animals in artificially designed special visual environment to observe the effects of environment on the development of eyeballs, and have made some achievements. As Wiesel tarsorrhaphy macaques, formed under the cover of ankyloblepharon, translucent film formed on the front, in the bright place feeding. The 5 monkey is unilateral eyelid suture after 18 months, open the suture, determination of the diopter and eye length and streak retinoscopy after enucleation after cycloplegia. Results show that the formation of -13.5D sutured eye myopia, eye and axial length increased by 20%. There was no change in diopter and eye axis for 17 months because of mature maturity of No. 8 monkey. No. 2 monkey has just been sutured after birth, and only 6 weeks to become -2.75D's myopia. In 1979, Wiesel and other eyelid sutured monkeys were fed under all black environmental conditions, and no myopia was found.
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answered by KAYLA
(1) the eye distance is too close. The adjustment ability of young eyes is very strong. When the distance between books and eyes is up to 7-10 centimeters, it can still see objects, but if we read frequently at this distance, writing will make the eye's regulation abnormal, so that we can form inflectional (regulatory) myopia and so called pseudmyopia. If the long-term excessive regulation, not flexible because of ciliary muscle, caused by excessive regulation to strengthen the convergence effect, make the extraocular muscle to exert pressure on the eyeball, increased intraocular pressure, intraocular tissue hyperemia, and teenagers eyeball tissue delicate, eyeball compression gradually extended, eyeball becomes longer, than the normal value on the formation of the shaft myopia, the so-called true myopia. The normal reading distance should be 30-35 centimeters.
(2) long eye time. Read and write homework, watching TV for 3-4 hours without a break, even the night before sleep and rest, which not only affect the body health, but also make the eyes burden, intraocular muscles long time in a state of tension and not rest, in the course of time, when looking at the distance, the eye muscles can relax in spasticity. So far are fuzzy and the formation of myopia. Generally speaking, reading and writing or watching TV for 40-50 minutes should rest for a moment or look far away.
(3) the light is too strong or too weak. If the light is too strong, such as sunlight written, will cause a strong reflection, irritation of the eyes, make eye discomfort, it is difficult to see the font, on the contrary, the light is too weak, writing poor lighting, eyes can not clearly see the font, the head will move, close to the book, the above two kinds of circumstances can eye fatigue, eye regulation of excessive or spasm of myopia.
(4) reading in the driving or walking. It is bad for the eyes to read or read in a walking car while walking. Because the car is shaking, the body is shaking, the distance between the eyes and books is not fixed, and the lighting condition is not good, which aggravates the burden of the eyes. Often, it can cause myopia.
(5) lie in a book. It is a bad habit to read in bed. Because people's eyes to maintain the level of the state of reading, so that adjustment and collection (influx) agreed to reduce eye fatigue. If you read on the bed, eyes in the state level, distance between eyes and a book is not consistent with the view about the books are inconsistent, uneven illumination, will make the eyes and easy to adjust tension in the book closer to the eyes, it can aggravate the burden on the eyes 2-3 times, day long form myopia.
(6) lack of sleep. When the lack of sleep, the second day tired, dizzy, the brain is not fully rest, failed to eliminate fatigue, heavier burden on the eyes, the occurrence of myopia. Lack of sleep is one of the most important reasons for the formation of myopia.
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answered by PAT
Maybe you haven't really known that: lack of sleep and lack of sleep are very important reasons for the formation of myopia. When driving or walking, reading increases the burden on the eyes, which often causes myopia. If the lighting is too strong or too weak, if the light is too strong, such as sunlight, writing and so on, it will make the eyes uncomfortable, it is difficult to see the font. On the contrary, if the light is too weak and close to books, the two situations are very likely to suffer from myopia.
Myopia has caused so many inconveniences to our life. So how do you treat it? Here I recommend a method for everyone to refer to, but the treatment is different from people, so you must remember to go to the hospital to make sure of the treatment. For the treatment of myopia, if it is a long time do not want to wear glasses to improve eyesight, can the eyes inside some irritation of the use of laser surgery, is slowly getting better, and with laser surgery for eye treatment of this phenomenon, the vision will gradually improve, and can also change the current phenomenon
For each of us, the eyes are very important, then prevention is a very important problem. How to prevent myopia? This is the question everyone wants to ask. Computer operators should eat relatively balanced meals three times a day, eat breakfast well, have enough nutrients, eat more protein containing Chinese food, have a light meal after dinner, and choose fresh vegetables and fruits. We should also be conscious of the choice of food to protect the eyes, to protect the health of the eyes, to prevent myopia and other diseases of the eyes.
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