Abstract: in China, for a long time, it has not only confirmed the existence of refractive myopia, but also regarded it as the mainstream of myopia and the inevitable law of the occurrence and development of myopia, and designed a unique theory of “pseudomyopia”., Refractive myopia refers to myopia caused by the change of refractive factors such as lens while the axis length remains unchanged (or within the normal range). 1 according to the refractive components, (1) axial myopia: myopia caused by the extension of the eye axis. Generally, the ocular axis increases by 1mm and the myopia degree increases by -3.00d. In high myopia, especially malignant myopia, the extension of ocular axis is very serious, and obvious exophthalmos can often be seen., (2) curvature myopia: myopia in which the curvature radius becomes shorter due to the enhanced curvature of the front of the cornea or the surface of the lens, so that the parallel beam is prematurely focused in front of the retina after entering the eye., (3) index myopia: refers to the myopia state in which the parallel beam is prematurely focused in front of the retina after entering the eye due to the increase of refractive index of aqueous humor and lens and the increase of refractive power., 2 according to diopter, ① mild myopia: myopia -3.00d (300 degrees) < -6.00d (600 degrees), some fundus changes in leopard pattern.,
refractive myopia refers to myopia caused by changes in refractive factors such as lens with unchanged axial length (or within the normal range).
1 is divided into
(1) axial myopia: myopia caused by the extension of the ocular axis. Generally, the ocular axis increases by 1mm and the myopia degree increases by -3.00d. In high myopia, especially malignant myopia, the extension of ocular axis is very serious, and obvious exophthalmos can often be seen.
(2) curvature myopia: myopia in which the curvature radius becomes shorter due to the enhanced curvature of the front of the cornea or the surface of the lens, so that the parallel beam is prematurely focused in front of the retina after entering the eye.
(3) index myopia: refers to the myopia state in which the parallel beam is prematurely focused in front of the retina after entering the eye due to the increase of refractive index of aqueous humor and lens and the increase of refractive power.
2 are divided into
according to diopter. ① mild myopia: myopia < -3.00d (300 degrees), general fundus no pathological changes.
② moderate myopia: myopia > -3.00d (300 degrees) < -6.00d (600 degrees), some fundus changes are leopard like.
③ high myopia (pathological myopia): myopia > -6.00d (600 degrees) often causes degenerative lesions of vitreous and fundus, of which > – 10.00d (1000 degrees) and serious pathological changes of fundus are also called malignant myopia, which is mostly related to genetic factors.
3 are divided into
according to refractive characteristics. 1. Bending myopia is caused by too strong bending of cornea or crystal surface.
2. Axial myopia is caused by the excessive development of the anterior and posterior axis of the eye.
3. Index myopia is caused by high refractive medium index.
4. Positional myopia is caused by the forward movement of a refractive medium in the eye (mostly the lens), which is rare.
on the premise of static refraction, distant objects can not converge in the retina, but form a focus in front of the retina, resulting in visual deformation and blurring of distant objects. Shanghai Xinshijie ophthalmic hospital said that in addition to being unable to see clearly, myopia also has other hazards, such as causing a series of serious complications and affecting people’s health. Therefore, the harm of myopia should not be ignored and must be paid attention to.
4 overview of refractive myopia theory
axial theory refers to that axial elongation is the essence of myopia, and the occurrence and development of myopia is the process of axial elongation. Myopia is caused by lengthening of the ocular axis. The axial theory of
is based on: ① the axial length of myopic eyeballs in vivo and in vitro is prolonged correspondingly; ② Organic changes such as arc spots can be seen in the fundus of the eye; ⑧ Diopter deepening and visual acuity decline were generally progressive; ④ The results of animal experiments showed that ⑤ the change of regulatory function was not obvious in myopia (including in the early stage). Some scholars not only believe that myopia is axial; And this kind of myopia is called “axial myopia”.
as mentioned earlier, myopia is caused by the extension of the ocular axis. The earliest report is found in Morgagni (1761). Tpoh score although there was anatomical evidence for the axial theory of myopia at the beginning, some people held no opinion in their early years. Although it is recognized that the axial length does play an important role in high myopia, it should also be noted that there are two main situations in the nature of myopia: first, the human eye has a variety of refractive components, and the axial length is one of the factors, but the final refractive state is determined by the combination of the relationship between the refractive components, which is mainly affected by the structure, shape and position. The second is the change of refractive performance, such as the role of lens refractive power. The core refractive component of refractive myopia is lens, and its mechanism is regulation.
Steiger believes that the axial theory can not be used to explain all the phenomena of myopia. Each refractive component has a certain variable range. For example, the corneal refractive power can be in 38 Between O and 48.0d, the final refractive state of human eye depends on the combination of cornea and axial length. The axial length of myopia does not necessarily belong to pathological value, and the role of regulation in the occurrence and development of myopia also appears from time to time in future research reports. The theoretical basis of “refractive myopia” is the regulatory mechanism, which has been confirmed by clinical observation and experimental research data. The crystal body has obvious function structure changes in near vision activity. The theory of accommodative myopia can well explain a large number of myopia phenomena, and its logical reasoning is easy to be accepted by people. The Japanese Society of ophthalmology has discussed and pointed out that acquired myopia is caused by near employment → continuous adjustment → increased ciliary muscle tension → increased lens power. Sato Tong is a representative figure of this school. After long-term research, he insists that myopia below moderate is caused by acquired excessive near work, continuous adjustment, ciliary muscle tension and increased lens diopter, which is a long-term adaptive resultNever deny the axial theory.
strictly speaking, refractive (or photorefractive) myopia should refer to myopia caused by the change of refractive factors such as lens with constant axial length (or within the normal range). Its essence is to emphasize the role of environmental factors.
5 pseudomyopia theory
in China, for a long time, it has not only confirmed the existence of refractive myopia, but also regarded it as the mainstream of myopia and the inevitable law of the occurrence and development of myopia, and designed a unique theory of “pseudomyopia”. The main basis is: ① clinical observation and experimental research confirm that myopia can occur by regulating tension or spasm; ② Eye drops of atropine may improve vision; ③ The prevalence of myopia in close workers increased significantly; ④ Taking some relaxation measures (such as fog vision, etc.) can improve vision, etc. Therefore, accommodation is regarded as the only (or most important) factor in the formation of myopia, and the myopia induced by the increase of visual proximity load is equivalent to accommodative or refractive myopia. It is not only juvenile myopia, but also all myopia go through the process of pseudo → semi true and semi false (mixed) → true myopia, that is, functional myopia gradually transition to organic myopia. The refractive degree of myopia also changed from low to medium to high. Myopia is reversible (at least in the false, half true and half false stage), so it can be prevented and treated in a certain period of time.
6 myopia harm
harm 1 causes complications: if you get myopia without timely treatment, not only the degree will continue to deepen, and eventually become high myopia, but also lead to complications such as retinal detachment, macular hemorrhage, glaucoma and cataract, and even blindness.
harm 2 harm physical and mental health: due to children’s myopia, they are unable to participate in a variety of sports activities, affecting their normal physical development, resulting in children’s physical weakness and diseases, and their physical and mental health is greatly affected.
harm 3 low quality of life: due to children’s myopia, daily life is extremely inconvenient. For example, there are many difficulties in communication, traveling and participating in recreational activities, resulting in psychological obstacles and low quality of life. Harm 4 of
is easy to be damaged: after children get myopia and wear glasses, because children are lively and active, if they are accidentally hit and broken, their eyes will be stabbed in light cases and blindness in severe cases.
harm 5. Academic performance decline: children with myopia can’t see words clearly without glasses. Wearing glasses is easy to cause visual fatigue, inattention and academic performance decline.
harm 6 and affect children’s future: children have myopia, there are great restrictions on entering school, choosing majors and employment, and their future is greatly affected.
endanger 7 genetic offspring: modern medicine has proved that myopia due to acquired factors will also be inherited if it is not treated in time.
axial myopia is true myopia. Generally speaking, it is a state in which the eyes can see close and clearly, but can’t see far, that is, they can only see close and can’t see far. Children and teenagers are studying in school. They spend a long time reading, writing and other near work. When looking at near objects, the eyes should use the adjustment function, that is, the ciliary muscle in the eyes should contract. Long-term near work or improper overuse of the eyes, such as reading novels, playing video games and watching TV, can make the ciliary muscle contract continuously and be in a state of spasm, If there is no pathological change in the fundus, it is called pseudomyopia, also known as regulatory myopia; If pathological changes occur in the fundus, it is called true myopia.
axial myopia is generally divided into two types: 1 Pseudomyopia is caused by ciliary muscle spasm. The lens cannot relax. The diopter of the lens is higher than that of normal people. The refracted light falls in front of the retina and can’t see clearly in the distance. The ocular axis did not grow.
2. True myopia. It is because the axis of the eye grows, which causes the retina to move backward. The light refracted by the lens can only fall in front of the retina and can’t see things far away.
generally, early myopia is mostly caused by pseudomyopia, and then develops to axial myopia. In the two stages, the two kinds of myopia may be mixed. To prove pseudomyopia or axial myopia, go to the hospital for mydriatic optometry to see if your eyesight can return to normal. Can recover is pseudomyopia.
axial myopia occurs in adolescents. In the stage of development and growth, myopia deepens year by year with the increase of age It does not develop or develops slowly after maturity. The degree of myopia rarely exceeds 6D, and there is no degenerative change in fundus. A few axial myopia occur earlier (between 5 and 10 years old) and progress 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. It is called degenerative myopia (also known as pathological myopia) Once high myopia is formed, the eye is easy to develop into pathological myopia, and the pathological changes of fundus are almost irreversible In general, high myopia patients with genetic factors are not short and deepen in adulthood, and many can develop into disease Patients with
axial high myopia have deep atrium, large pupil and slightly prominent eyeball due to the length of anterior and posterior axis. Fundus examination is often due to the reduction of pigment in the retinal pigment epithelium, choroidal atrophy, the disappearance of its small blood vessel network, and the large blood vessels can be seen through, which makes the fundus show red and brown thick stripes, called leopard shaped fundus. A white or gray crescent spot can be seen on the temporal side of the optic disc, which is called myopic semilunar spot. 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 sclera in the posterior pole of
continues to expand backward. Knee crack like stripes and subretinal neovascularization can appear in the macula, and plaque atrophy and degeneration can appear in the nearby retina and choroid, resulting in posterior scleral staphyloma. When myopia occurs to this extent, the posterior pole of the eye expands, cystic degeneration occurs around the retina, and terrible retinal detachment occurs The macula often has pigment hyperplasia, even bleeding, forming atrophic spots, which is seriousMacular lesions that damage vision and high myopia have become one of the main causes of blindness.
1. Once myopia is found, first go to a regular eye shop to check the degree, get appropriate glasses, and choose RGP if possible.
2. Don’t trust the myopia therapeutic instrument on the outside market In fact, most of them cheat money.
3. Check your eyesight and eyes regularly and do more eye exercises.
4. Pay attention to physical exercise at ordinary times and do more outdoor activities to enhance your physique, (special attention should be paid to avoid strenuous exercise for high myopia.
5. Do two things and two don’t:
two things: (1) read and write correctly, and keep your eyes about one meter away from the book. (2) take a break from reading or watching TV for about one hour and look into the distance.
Second, don’t: (1) don’t read or write in dim light and direct sunlight. The lighting on the desktop should not be less than 75 foot candles. (2) don’t read in bed, walking or riding.
1. Insufficient sleep
When sleep is insufficient, the next day is depressed, dizzy, the brain does not have enough rest, fatigue is not eliminated, increasing the burden on the eyes and promoting the occurrence of myopia. Lack of sleep is a very important cause of myopia.
2. There is too little time for outdoor activities.
now the living space is too narrow. Children spend most of their time indoors and use their eyes at close range. Children’s eyes have strong adaptability, and they will adjust themselves to adapt to this close range. Moreover, more time in the house, more opportunities to watch TV and play computer. If you don’t pay attention to distance and posture, it’s easy to make your eyes too tired.
in the outdoors, no matter how close the object is, it must be farther than the house. Studies have shown that children who often exercise outdoors suffer from myopia less than children who don’t go out often.
3. Children who play iPhone and iPad
for a long time have not yet finalized their eyeball development, especially children aged three or four, whose eyeballs themselves are not fully developed and their eyes are still hyperopia. Some children hold the iPad for a long time to play a game that requires accuracy, such as angry birds. They will involuntarily adjust the focus of their eyes, gather their eyesight and stare at the screen. At this time, the ciliary muscle and internal rectus muscle are in a tense state. If they are not released in time, it is easy to cause adjustment spasm and pseudomyopia. Once parents do not find and intervene in time, it is easy to become irreversible true myopia. On the other hand, due to the excessive collection of internal rectus muscles, a “cockfighting eye” may be formed. If it is not improved in time, one object will become two, forming diplopia. The high incidence of myopia in
adolescents is worrying. The advertisement of “one cure for myopia” is doubtful. Ophthalmologists believe that up to now, there is no effective treatment for true myopia. Therefore, it is proposed that the treatment of pseudomyopia and the prevention of the occurrence and development of true myopia are the research direction in the future.
how to protect eyesight
I. the light should be sufficient, and the reflection should avoid the comfortable light of
, which can get good visual information. Too strong or too dark light will bring adverse effects to the eyes. Therefore, the desk where teenagers usually read should have a side lamp device, which aims to reduce reflection and reduce eye damage.
2. The continuous reading time should not be too long.
teenagers read and write, watch TV and use the computer for several hours without rest. Some students even go to bed late at night, which not only affects their health, makes the eyes overburdened, and is easy to cause regulatory (or functional) myopia, that is, pseudomyopia. Moreover, it will also make the extraocular muscles produce pressure on the sclera tissue of the eyeball wall, increase the intraocular pressure and congest the intraocular tissue. Therefore, students should take a break every 50 minutes.
III. sit upright and at a moderate distance.
don’t bend over or read on the table, let alone lie in bed and read on your side. The distance between eyes and books should be kept at 30-35 cm, the distance between body and desk should be kept at about 10 cm, and the angle between books and desks should be kept at 30-45 degrees. If the book is placed horizontally on the desktop, you should lower your head slightly forward when reading, so it is easy to move the book close to your eyes and increase the burden on your eyes by 2-3 times, resulting in fatigue of neck muscles and nape, and unconsciously tilt forward, which will lead to decreased vision in the long run.
IV. watch less TV and use less computers.
try to reduce contact with televisions, computers, game consoles and other electrical equipment that radiate to human eyes, because the X-rays radiated by the picture tube can consume a lot of rhodopsin in the retina and significantly reduce vision.
computers should preferably use liquid crystal displays to reduce the damage of electromagnetic waves to eyes. Students who often play video games are more likely to damage their eyesight, and low vision students who play video games since childhood can’t even correct their eyesight with glasses. The reason is that the function of retina and macula has been damaged.
v. sleep should be sufficient, pay attention to eye hygiene,
work and rest time should be regular, and sleep should be sufficient. Lack of sleep will lead to conjunctival congestion, increased secretion, photophobia and tears, eye soreness and other conjunctival and keratitis. Try to avoid eye damage caused by wind, sand, smoke, ultraviolet, infrared, chemicals and medical supplies. Personal hygiene shall be kept clean. Personal items such as towels, washbasins and handkerchiefs shall be used by special personnel, and other items shall not be used as much as possible, so as to avoid cross infection, eye diseases and vision loss.
6. You can’t read while driving or walking. Some teenagers like to read while walking, or read in the walking carriage, which is very bad for their eyes, because the carriage is shaking, the body is shaking, and their eyesThe distance between eyes and books cannot be fixed, coupled with poor lighting conditions, which increases the burden on the eyes. Often, this may cause myopia.
VII. Doing more eye exercises and outdoor sports
eye exercises is a concrete embodiment of the importance of eye health care in primary and secondary schools in China. By massaging various acupoints and muscles around the eyes, stimulating nerve endings, increasing blood circulation around the eyes and regulating eye metabolism, so as to eliminate fatigue and enhance vision, The purpose of preventing myopia. In addition, more contact with natural scenery such as green mountains and green waters is also conducive to the health of eyes.
VIII. Pay attention to the dietary structure, and the nutritional intake should be balanced. The nutritional intake of
should be balanced. Partial eating or excessive intake of sugar and protein, resulting in the lack of trace elements such as zinc, calcium and chromium, is not conducive to visual health. The prevention method is to eat more vegetables, fruits, liver, fish and other foods. The genetic factors of
are the main causes of high myopia. The occurrence of high myopia in China is autosomal recessive inheritance, that is, both parents are high myopia, and 100% of their children are high myopia; If one of the parents is high myopia, 50% of the children are high hereditary myopia; But some are not complete.
prevention and treatment of
congenital myopia although there are genetic myopia factors, through active prevention and treatment, children can still maintain healthy vision. Traditional Chinese medicine advocates “nurturing the innate”, and believes that myopia astigmatism can be nurtured through daily diet, exercise and treatment, so as to make up for genetic factors and restore healthy vision. Parents should try their best to let children eat less sweets and more foods rich in vitamins A, B1, B2, C and E. Common foods rich in vitamins include eggs, milk, fish, meat, liver, fresh vegetables and fruits.
to prevent acquired myopia, we also need to pay attention to improving the visual environment, standardizing the lighting in the classroom, the ratio of the light transmission area of the window to the classroom is not less than 1:6, there is no reflection on the blackboard, develop good writing posture, take a rest for 40-50 minutes, do eye exercises, do not walk, take a bus, lie down, read and write in direct sunlight or dark light, etc. We should also reduce students’ homework and increase outdoor activities, which can not only enhance their physique, but also prevent myopia.
if children are found to have signs of myopia, they should go to the hospital in time for examination, mydriasis optometry and wear appropriate glasses. In addition, we must pay attention to that glasses are medical supplies rather than general commodities, and the quality is very important, so we must go to a large hospital or a reputable glasses store to match glasses.
experts finally pointed out that due to children’s weak sense of self-control, parents and teachers should help children take care of their eyes. If they do the following points, they can effectively prevent children’s myopia and other eye diseases: first, they should develop good hygiene habits, eat reasonably, exercise their body and ensure their physical and mental health; Second, we should correct bad habits and develop good eye hygiene; Third, we should regularly go to the eye hospital to check the eyes, especially patients with high myopia, and find eye diseases in time, so as to find and treat them early.
“there are 9 million low vision patients in China, of which 80% can avoid vision loss through early prevention.” It is precisely because many children with high myopia did not receive enough attention from childhood, missed the best age for visual acuity correction, and finally caused amblyopia. About 20% of the
myopia population are hereditary. If someone at home suffers from hereditary myopia, you should pay attention to observation from the birth of the child. You can check whether the child has strabismus and other symptoms first. When the child is 1 year old, you can go to the hospital for infant vision examination. Generally, the degree of myopia can be found when the child is 3 years old.
often encounter 3-year-old children with myopia in clinic. These children must immediately correct their eyesight, that is, wear glasses, so as not to affect their child’s eye development. Because if the eyes can’t see clearly for a long time, the child will slowly refuse to use the eyes. Wearing glasses for the child in time is to enable them to use the eyes normally, so that the child’s eyes can develop normally. If not corrected in time, these children with high myopia heredity will generally have amblyopia before the age of 6, and may have high myopia complications such as retinal nerve atrophy and cataract.