Question 1: What is myopia? Almost everyone knows about this issue. The so-called myopia is a state of not seeing clearly at a distance and seeing clearly at a near, which needs to be corrected by wearing concave lenses (myopic lenses). From an ophthalmological point of view, orthophoria (refractive eye) is a state in which the eye is loosely adjusted so that parallel light from 5 meters away, after being refracted by the eye’s refractive system, falls exactly at the base of the eye (retina). Myopia, on the other hand, is a condition in which the eye is loosely adjusted so that parallel light rays from 5 meters away, after being refracted by the eye’s refractive system, fall only in front of the fundus (retina) of the eye and are therefore blurred on the retina. If myopic eyes want to see clearly, they need two conditions: one is to move the object closer and the other is to wear a concave lens with the right prescription. Question 2: Why does myopia occur? This is a very complex question, and there are many hypotheses and speculations about the causes. There are two main types of factors that cause myopia: genetic factors and environmental factors. High levels of myopia, especially progressive myopia, have a clear genetic predisposition, but most myopia occurs mainly due to environmental factors, and genetics is not decisive! Case 1: Before the Americans settled in Alaska, there were no Eskimos living there with myopia. Later, the Americans brought “civilization” to Alaska, offering a variety of cultural remedial classes to teach English to the locals. The Eskimos became more and more civilized, but myopia appeared in the population, and the incidence increased every year. Case 2: The eagle is the best-sighted animal in the world, its vision can reach 4.0 (international standard vision chart, the normal standard for human is 1.0), which is four times that of normal human eyes, so even if the eagle soars in the sky for miles, it can effortlessly find the hare hiding in the grass. In ancient times, it was very important to have sharp eyesight like eagles. Those with weak eyesight would be eaten by wild animals or killed by enemies, and at that time there was no method of correcting eyesight with glasses, so it is assumed that the normal eyesight of ancient human eyes should be above 2.0. Case 3: Since ancient times, Chinese people have been learning to write brush characters. The old saying “you can’t read a bucket of characters” was used to describe the illiterate people of that time. It can be seen that the font was relatively large at that time. Later, with the invention of movable type printing, the fonts printed on the books became much smaller, and even more so, “fly-head small characters” appeared. Since then, the incidence of myopia in the Chinese population has increased greatly, so much so that in the Ming Dynasty there were myopic literati like Mr. Zhu Zhi Shan. The mechanism of environmental factors influencing the formation of myopia Every human being with normal congenital development is commonly farsighted at the time of birth because of the short anterior and posterior diameter of the eye (about 16 mm). At age 3, the eye is 1 mm shorter than the normal adult eye, which means 300 degrees of hyperopia from an optical calculation point of view. At the age of 6 years or less, if there is no visual fatigue and near and far vision is close to normal (international standard visual acuity 1.0; logarithmic visual acuity 5.0), a mild hyperopia detected by optometry should fall under the category of physiological hyperopia. In other words, normal human eyes show symptoms of hyperopia until the age of 6 years, while those who develop orthopia early before the age of 6 years may often have hereditary myopia (early refractive development). It is well documented that visual development is not perfected until about 8 years of age, when the orthophoric eye state is reached. There are many environmental factors that influence the formation of myopia, the main one being the increase in the near-visual load. Animal experiments and epidemiological data confirm that prolonged and stressful near-visual work is closely related to the development of myopia. Of course, inadequate lighting conditions, nutritional disorders, micronutrient deficiencies, and organophosphorus pesticide pollution have also been reported to affect the occurrence of myopia in students. In general, prolonged and intense near-sighted work is the main cause of myopia formation. This is because prolonged near vision causes a serious increase in the tension of the regulation of the human eye, breaking the balance of forces between the regulation of the human eye tissue, the shape of the eye is forced to change, and the eye axis grows, which is the most common axial myopia. For every 1mm increase in the length of the eye axis, myopia increases by 300 degrees! Young children’s eyes are farsighted and need to use stronger adjustments when looking at close objects, making them more prone to eye shape changes. As mentioned earlier, the younger you are before the age of 6, the greater the degree of hyperopia and the stronger the regulation needed to look closer. Therefore, one of the preventive measures (this point is the most important): before the age of 6, in the critical period of eye development, should minimize close work, so that children more outdoor activities, so as to enhance physical fitness and reduce the occurrence of myopia, why not? Preventive measures two: Nowadays, children’s learning pressure is particularly high, many parents expect their children to become dragons, expect their daughters to become phoenixes. Therefore, it is almost impossible to be “lazy” and not study. Here, you can try some methods, both to learn knowledge, but also to prevent myopia due to eye strain. 1, eliminate computer games, watch less television (no more than an hour a day); 2, reading and writing assignments should not be too long, generally in an hour or so should get up and walk around, look away; 3, when reading and writing, pay attention to posture and reasonable lighting. Pay special attention to: not lying down to read, or reading on a moving vehicle. Do not hunch your back or lower your head, and also pay attention to the posture of holding the brush. In my opinion, writing with a brush is the most scientific: hold the pen high, keep your eyes far from the paper, and keep your back straight. Unfortunately, now that everyone is writing with pencils, ballpoint pens, fountain pens, etc., many children hold the pen in a very incorrect position: the grip is too low, and the thumb also blocks part of the line of sight, causing them to write sideways, bend their heads, and in some cases, even bury their little faces in the desk. Therefore, correct pencil grip must be emphasized! From the analysis of various animals in nature, the eyesight of carnivores is generally sharper than that of herbivores, which may be the inevitable result of “the weak are stronger than the strong” and “natural selection”. However, it can also be seen that the outer wall of the eye (sclera), like muscle tissue, requires a certain degree of strength and toughness. If it is not strong enough, it will be easily stretched and form myopia, especially high myopia. Looking around us, we can find an interesting phenomenon: people with high myopia (myopia of 600 degrees or more) are relatively weak and may have had bad habits of picky eating as children. Therefore, the prevention of myopia measures of three: should eat more fresh protein-rich food, such as lean meat, animal offal, fish and shrimp, milk, eggs, beans, etc., and eat less sweets and starchy food. In addition, eat more roughage and less finely processed food. The eyes also need calcium, calcium has the role of eliminating eye tension, such as shrimp are rich in calcium, burning ribs soup, sugar and vinegar ribs and other cooking methods can increase the intake of calcium. Overall, the prevention of myopia in young people is a long and arduous task. Keeping children growing up healthy in the sun and minimizing the burden on the eyes is the key to preventing the occurrence and development of myopia.