Author: Zhou Shiping time: 2010-11:38 Classification: default classification label: myopia Preface: I follow two principles in writing this article.
1. Let the general readers understand this article. If you can't understand any part of this article, you can read the seventh part of this article, which will make you understand the full text.
Let this article make the world a better place.
At present, the myopia rate remains high. There are not one or two myopia patients, nor tens of thousands, but hundreds of millions of myopia patients. People who are not nearsighted don't know the harm of myopia because they lack personal experience of myopia. Then this paper will show the harm of myopia to these non-myopia patients and myopia patients who have insufficient understanding of myopia. Because myopia patients have personal experience of myopia, I should be able to say it more easily. The myopia rate is so high, and it remains high. I believe that optometrists have racked their brains. However, because they didn't find the right method, they failed to reduce the myopia rate. This paper will solve the problem of myopia with a brand-new concept. I believe that if this paper can be widely accepted, it will be a time when the myopia rate will drop rapidly.
1. The harm of myopia
There are two explanations for the harm of myopia: untreated and treated.
Untreated situation, that is, no measures have been taken for myopia. In other words, after suffering from myopia, he did not wear glasses and did not undergo any surgical treatment. Obviously, because most of the information of a normal person is obtained by eyes. If the eyes are nearsighted and left untreated, his/her vision will be blurred when he/she looks far away, which will naturally make life and work extremely difficult. The deeper the degree of myopia, the greater the harm caused by myopia. The most common complications of high myopia are retinal tear, retinal hemorrhage and retinal detachment. In addition, high myopia can cause other worrying complications. Let's talk about handling the situation first.
After suffering from myopia, there are many choices, either wearing pince-nez or contact lenses or having surgery. It should be noted that not everyone can choose pince-nez after myopia. For example, bald myopia patients are not suitable for wearing pince-nez because the nose bridge is too low and the glasses will slide down, which will not achieve the effect of refractive correction. Once again, balding myopia patients should never choose pince-nez because you can't achieve refractive correction with these glasses, and even your eyesight will be damaged if you wear them forcibly. Because there are many ways to treat myopia, here are some methods and their disadvantages for myopia patients. Because these methods are used to treat myopia, that is to say, if there is no myopia, there will be no such methods. So myopia is the cause of these disadvantages. Naturally, these disadvantages can also be regarded as the harm caused by myopia.
Wearing pince-nez in this way and eating hot noodles in winter will make the glasses foggy and affect our eyesight; When it rains, the rain falls on the lens and also affects vision; Always take the time to clean the lens; -Wait. Even if the weather is clear and the lenses are clean, strenuous exercise will make the glasses move, which will affect the vision. Moreover, the binocular visual field obtained after refractive correction with pince-nez is obviously smaller than that of normal eyes, and both visual field and visual field are the key prerequisites for sports ability. Therefore, the sports ability of myopia patients wearing pince-nez is not as good as that of non-myopia patients as a whole. Naturally, their physique is worse than that of non-myopic patients.
Wear contact lenses. I quoted the words in "Ophthalmic Flexion Optics [4th Edition]" edited by Xu Guangdi, a military medical science publishing house: "Although the lens is soft, with high water content and good maintenance measures, the contact lens is a foreign body between the cornea and conjunctiva, which will inevitably produce different degrees of pathological reactions after a long time." In addition to the complications caused by contact lenses, the use and care of contact lenses are not easy. In addition, because contact lenses slide more or less on the cornea, the vision after wearing lenses is not as stable as that of normal eyes.
Myopia surgery. "Eye flexion" has: "The treatment of myopia is a big problem in the medical field, and there is no really ideal and effective treatment method so far." In other words, there is no really ideal myopia surgery at present. At present, myopia surgery has its own shortcomings. Just take PRK and LASIK as examples. They may all lead to their own complications. In addition, myopia surgery is still controversial. Britain even stopped laser surgery for myopia.
2. Causes of myopia formation and deepening
First of all, I gave the definitions of "eye diopter size" and "sight distance". Let any two eyes a and b have x diopter and y diopter, if X >；; Y, the diopter of eye A is greater than that of eye B ... such as+1d >; - 1D，+2D & gt； 0D, 0D>- 1D, etc. The distance between the eyes and the target is called sight distance.
I put forward an important optical law of eye flexion: the smaller the long-term visual distance, the smaller the diopter of the eye; or vice versa, Dallas to the auditorium The smaller the sight distance, the smaller the diopter. or vice versa, Dallas to the auditorium This law is called the first law of eye diopter change, or simply the law of eye flexion. This law explains the relationship between eye diopter, sight distance and time. In addition to short sight distance, there are other reasons to form and deepen myopia. Such as traumatic myopia, toxic myopia, diabetic myopia and so on. However, most myopia is formed and deepened because the visual distance is too small. Therefore, the law of eye flexion plays a theoretical supporting role in preventing most myopia. The proof of eye flexion law is as follows.
Proof materials 1. "Birds and animals on land live in the air with good visibility. In order to adapt to survival, they need good farsightedness, so their eyes are almost all slightly farsighted or upward. Primitive humans mainly used hyperopia to hunt food and defend against enemy attacks, and most of them were positive or mild hyperopia. The mild hyperopia of modern human newborns may represent the refractive state of our ancestors' eyeballs. -Excerpt from "Eye Bend"
Evidence 2. "Half of the young cadres of the Guangzhou Military Region Surveying and Mapping Brigade are engaged in field surveys and half are engaged in drawing detailed military maps indoors. Most of the latter can hardly see the distance after a lot of close work for weeks, and they can recover after a short rest. A few years later, refractive examination found that the incidence of myopia in the indoor operation group greatly exceeded that in the field operation group. " -Excerpt from "Eye Bend"
In addition, many animal experiments done by optometrists can also prove this rule.
According to the law of eye flexion, all eyes, whether they are treated or untreated myopia or non-myopia, that is, all people's eyes, as long as you can still see, the eyeball is still plastic and have the visual environment and visual habits to get myopia or deepen myopia, then it is possible to get myopia or deepen myopia.
It can also be inferred from the law of eye flexion that for the same person, a certain visual environment and visual habits roughly correspond to a certain eye diopter. For example, if a person suffers from -2D myopia for a long time under certain visual environment and habits, and then wears 200-degree myopia glasses, the visual environment and habits have not changed since then, then the overall eye diopter of glasses and eyes is likely to develop to -2D when wearing glasses, and then the eye diopter will be less than -2D after taking off glasses. Therefore, children must pay attention to improving the visual environment and visual habits after wearing glasses prematurely. The above also shows that wearing glasses increases myopia to some extent, but it is not completely correct.
As for the relationship between genetic factors and environmental factors of myopia. Think about it, if there is no myopia, will there be myopia inheritance? So for myopia, environmental factors play a decisive role. Not only do I think so, but also in Eye Bend: "In the long run, heredity is also determined by the environment." 3. Ways to prevent myopia
Here are several ways to prevent myopia, all around the law of eye flexion. And because the vast majority of myopia is formed during school study, these methods are related to learning.
Method one. Improve learning light. Pay attention to the color and intensity of light. As we all know, in a certain range, the stronger the light, the more clearly people can see, but too strong light will also damage their eyes. So the indoor light intensity must be appropriate. Seen from the light color, fluorescent lamp is an ideal light source. In addition, the light of fluorescent lamps is softer than incandescent lamps, which is more conducive to vision. It should be noted that improving learning light includes two places, school and family. For home lighting, it is necessary to formulate corresponding lighting standards for learning. Especially for primary and middle school students, because they have too little knowledge, they naturally know very little about myopia, so parents should consciously provide good lighting conditions. Teachers and parents should impart appropriate myopia knowledge to primary and secondary school students. On this side of the school. When I was studying, the classroom light was broken for a while, and I didn't change it. The broken lamp is just above my head. So, because the light is too dim, I will put my eyes closer to the words in the morning reading. For improving lighting, I personally think it is better to formulate standards, which should include the type, location and opening time of light sources. For schools, there should also be special organizations or institutions to inspect and supervise lighting. Is it worth it? High cost performance! This has protected the precious eyesight of countless students. It should be pointed out here that learning lighting conditions not only refers to what kind of light source you want, but also includes the relative position of light source and table, people and so on. For example, someone gave such lighting conditions:
"Generally, the light source is about one meter away from the desktop, and a 40-watt light bulb is enough. If it is more than one meter, use a 60-watt light bulb. The light should come from the left or the front left, so as to avoid the shadow from affecting the light. " -Excerpted from a booklet on preventing myopia.
Method two. Print the words on the book a little bigger. For normal eyes [Note that normal eyes here include eyes that have obtained normal vision by wearing glasses, performing surgery, etc. 】, the bigger the thing, the farther away we are, the more clearly we see it; On the contrary, the smaller things, the more we can see them clearly. With the progress of science and technology, printing has also made great progress. So people also have the ability to print the words on the book smaller. Everything is measured. How big should the words be printed? What is worrying is that there is no corresponding standard so far. Scholars often suggest that 33 cm is the minimum visual distance of eyes. In fact, when the body feels more suitable when sitting and learning to write, the distance between the eyes and the words is about 50cm. So here I give the minimum standard of printed words, with 50cm as the minimum distance conducive to vision. This standard should be the smallest word that can be seen clearly at 50cm with the vision of 1.0. Obviously, the number of words in books such as Oxford Advanced English-Chinese Learning Dictionary and Xinhua Dictionary is too small by this standard. This standard is temporary. As for the size of the words in the book, it depends on the corresponding relationship between the size of the words and the myopia rate. As for the correspondence between text size and myopia rate, it needs to be clarified in the future. For characters, only the stroke thickness and stroke spacing are related to vision, so if you want to change the myopia rate by changing the characters, you must change the myopia rate by changing the stroke thickness and stroke spacing. Then someone said, "The bigger the word, the more paper is used for books with the same content, and the heavier the natural book." I said, for the first window of the human mind, we will only make money without losing money by doing all this.
In addition, it should be pointed out that from the law of eye flexion, farsightedness can not only prevent myopia, but also cure myopia [including true myopia], but farsightedness is a long-term method to cure true myopia. As for the effect, it remains to be studied. But what is certain is that children are definitely better than adults because their eyeballs are more plastic. When I say look far, I mean aim and look far. Among them, whether it is to prevent myopia or treat myopia (including true myopia or pseudomyopia), aiming at a distance is better than looking down, because you can't look down for too long, otherwise it will become a dull look. The aiming distance here means that you can choose hunting, shooting and other ways to get aiming opportunities.
For some methods to prevent myopia, I would like to criticize them here. It has been suggested that "don't read in the swaying carriage" is one of the precautions to prevent myopia. What is the basis of this sentence? Reading in a rickety carriage, at best, is fatigue due to frequent adjustment, leading to myopia. There are many unfounded preventive measures like this, which will only add trouble to solving the problem of myopia.
Four. Current situation of myopia treatment
At present, there are two ways to treat myopia. First of all, vision can not be stable for a long time after treatment. For example, OK glasses for myopia, because they are worn at night, inhibit corneal deformation and have immediate effects. They were popular in China for a while, but once they were not worn, they soon failed. The second is that the vision can be stable for a long time after treatment, but there are risks and side effects. For example, PRK and LASIK surgery. Although the first method is considered as a cure for myopia, there are other worse methods that can't treat true myopia at all. The national expert guidance group for myopia prevention and treatment of students tried about 50 methods for myopia treatment in the market. Some of them can improve their eyesight because they can relieve visual fatigue; Some can relax and adjust, relieve or treat pseudomyopia; In order to alleviate the causes of myopia, some can play a role in diagnosing or treating pseudomyopia and preventing true myopia. However, none of the items in the experiment has a definite therapeutic effect on true myopia.
In addition, some people take advantage of the psychology that myopia patients want to cure myopia without being threatened by side effects and dangers, and make money by hyping that drugs can cure true and false myopia. I have heard relevant programs on the radio. They advertised a drug called "rejuvenation brand brightening tablet" on the radio. It is said that this medicine can treat true myopia. I even believed it then. But as long as people remember that "there is no other way to treat true myopia except surgery." Then no one will be fooled by this again. In addition, I don't think there is any other way to cure myopia in a short time except surgery, even in the future. And any operation is dangerous and has side effects. Therefore, treating myopia is a helpless choice. At the same time, wearing short-sighted glasses is also a helpless choice. After myopia, you can only face helpless choices, so the best choice for treating myopia is to prevent myopia.
Only when the whole society is mobilized can myopia be prevented.
When preventing myopia, parents of students should pay attention to improving lighting, publishing houses and printers should print the words on books large enough, and schools should improve the natural lighting and indoor lighting of teaching buildings. It can be seen that preventing myopia cannot be done by one person, and it requires the joint efforts of the whole society. In other words, it is impossible for an individual to prevent his own myopia. If we rely solely on ourselves to prevent myopia, there will be events such as good scholars giving up learning because the words in the book are too small.
6. Historical changes of human sight distance
In primitive society, in order to hunt food and resist enemy attacks, human beings mainly used farsightedness. With the development of civilization, printing appeared, so human beings have more opportunities to see closer. With the further development of printing, the words on the book are printed smaller and the sight distance is reduced. In addition, the widespread use of computers in today's era has increased the opportunities for people to watch at close range. ——
From this, we can sum up the changing law of human sight distance in history: on the whole, the time when the sight distance is small is getting longer and longer, and the sight distance is getting smaller and smaller.
In this way, how can the myopia rate not rise!
Seven. Reading assistance group
The refraction of light is called refraction.
This paper is a paper in the field of optometry. Ophthalmic refractive optics is a science that studies the laws of refractive changes. Ophthalmic refractive optics is a branch of optometry. Optometry is a science that combines vision with light to study its laws. At present, Wenzhou Medical College and other universities have set up optometry majors.
The refractive power of a lens, called vergence, is also called refractive power. The unit is diopter [diopter, D], which is usually expressed by d. The refractive power of a lens is numerically equal to the focal length [expressed in meters] divided by 1. If the focal length of the lens is 2m, the refractive power of the lens is equal to 0.5D；; The focal length of the lens is 3m, and the refractive power of the lens is equal to 1/3D.
Eyes can see far and near because the contraction and relaxation of ciliary muscles cause the change of lens convexity. This ability of the eye is called accommodation. When the ciliary muscle is completely relaxed, the lens will be in the flattest state, and we call the eyes in the unadjusted state at this time.
When the eye is in a non-accommodation state, if the light energy emitted from a certain point A at a limited distance in front of the eye forms a focus on the retina through the refractive medium of the eye, the eye is called myopia, and the point A is called the far point of the eye; If the light from the outside to point B behind the eye can form a focus on the retina through the refractive medium of the eye, the eye is called hyperopia, and point B is called the far point of the eye. If the external parallel light can form a focus on the retina after passing through the refractive medium of the eye, the eye is called emmetropia, and it can be considered that the parallel light is emitted from point C at infinity, and point C is called the far point of the eye.
According to the definitions of myopia, emmetropia and hyperopia, the far point of myopia is limited to the eyes; The apogee of the eye is in front of the eye or infinitely far behind the eye; The far point of hyperopia is confined behind the eyes. The distance from apogee to eye [expressed in meters] divided by 1 is the value of eye diopter. If the distance is in front of you, add a negative sign before the value; If the far point is behind the eyes, add a plus sign before the value. For example, if the apogee of myopia is 0.5m away from the eye, then the diopter of this eye is-1/0.5 =-2d; The diopter of hypermetropia 2m away from the eye is+1/2 =+0.5d; For emmetropia, the apogee is one meter away from the eye, and a is positive infinity, so the diopter of emmetropia is equal to 1/a=0D.
However, diopter statistics show that there are very few eyes with diopter of 0, so 0D is not used as the standard of face recognition in daily life. For example, the standard of 0.00 d ~+0.75 d set by Stromberg in 1970 is usually used. For myopia, the smaller the value, the deeper the myopia. For example, -2D eyes are more nearsighted than-1D eyes; For hyperopia, and so on. Eye diopter is generally expressed in decimals, not fractions.
PRK surgery and LASIK surgery are both ophthalmic laser surgery.
Pseudomyopia: after atropine mydriasis, the degree of myopia disappears, which is manifested as face-up or hyperopia.
True myopia: normal myopia, that is, after mydriasis with atropine, the degree of myopia has not decreased or decreased by less than 0.5D
Mixed myopia: refers to the degree of myopia decreased obviously [greater than or equal to 0.5D] after mydriasis with atropine, but the emmetropia did not recover.
For the definition of "vision", due to the difficulty of uploading graphics, only a rough definition is given here. The ability to distinguish the smallest object is called vision. For example, when doctors check our eyesight, there are many "E" s with different opening directions on the eye chart. When standing at a certain distance l, the smaller the "e" that a person can see clearly, the better his vision at the distance l ... For everyone, the vision at different distances may be different. When we are nearsighted, our farsightedness will be weakened. 8. How is human high myopia formed?
Myopia with diopter less than -6D is called high myopia. It can be calculated that the apogee of high myopia is less than 1/6 meters from the eye. That is, when the long-term sight distance is greater than or equal to 1/6 meters, it is impossible to form high myopia. It is impossible to achieve a long-term sight distance less than 1/6m[ about 16.7m]. So it is impossible for humans to get high myopia?
Myopic glasses make it possible for humans to be highly myopic. Suppose a person's eye diopter changes from 0D to -3D due to frequent close-up shooting, then he is equipped with a pair of -3D myopia glasses. Later, due to long-term close-ups, the overall eye diopter of glasses and eyes was -3D. If he takes off his glasses, the diopter of his eyes is much less than -3D. In this way, it is possible to form high myopia.
Therefore, wearing myopia glasses is a necessary factor for the formation of high myopia due to too small visual distance. High myopia caused by too small visual distance accounts for the vast majority. Therefore, wearing myopia glasses is one of the necessary factors for the formation of high myopia in most human beings.
The long-term sight distance is one meter, even if myopia is formed, it is only possible to be more than or equal to one meter away from the eyes. That is, the long-term visual distance is one meter, even if myopia is formed, the diopter of the eye can only be greater than or equal to-1/aD. It can be seen that the greater the long-term sight distance, the lighter the deepest myopia that may be formed. It can be seen that when preventing myopia, the greater the sight distance, the better.
In addition, it can be seen from the law of eye flexion that there is a corresponding relationship between sight distance and eye diopter, which is worth studying by optometrists.