1. Why do myopic people hold books so close to look at them? When we hold books very close, the light will be diffused from the near (the light of distant objects is close to parallel), and then through the myopic eye just can converge on the retina, forming a clear image, and then held a little farther to become blurred, the higher the myopia, the closer to see clearly. Therefore, parents must take into account the possibility of myopia when their children hold books very close to read. 2. Is it better to be nearsighted, or not to be nearsighted? A: This is not a nonsense, maybe you really can’t answer it. The human requirement for their own refractive state is not unchanging orthopia (the ophthalmological meaning of orthopia is not zero, but -0.25 to +0.25DS). The physiological requirements for refraction evolve with age throughout a person’s life, such as less than 18 years old, +2.50DS to +1.50DS may be better, in the 18-30 years old stage, it is better to +0.75DS to +0.50DS. The transition to myopia is a natural requirement, for example, by 55 to 70 years of age, -2.25DS to -1.50DS is better for mild myopia, and above 70 years of age, -3.0DS is better for myopia. With the accumulation of human civilization and the progress of society, people are more and more inclined to read and work at close range, making the process of orthokeratology come early and forming myopia prematurely. As we all know, the human eye is like a highly sophisticated camera, and the switch between seeing far and seeing near is very sensitive and rapid, because the human eye has the function of “focusing” when looking at near, which is what is called adjustment in medicine. Orthoptic eyes need to pay more regulation when looking close, myopic eyes need to pay less regulation when looking close. In order to facilitate people to read and work at close range for a long time, the human eye gradually “becomes lazy”, through the refractive state of the eye changes, so that the active payment of the regulation is reduced, and replaced by a “once and for all” effect –Myopia. From the perspective of biological evolution, can you say that myopia is a degeneration? 3. What are the main factors that cause myopia? (1) Genetic factors Genetic studies of myopia have shown that there is a tendency for myopia to run in families, and that the percentage of family members of myopic patients with myopia is significantly higher than that of non-myopic people. So why is it that sometimes both parents are not myopic, but the child is? Most scholars believe that myopia is recessively inherited, meaning that both parents may be carriers of the myopia gene even if they are not myopic, and that the genetic chance of myopia occurring in offspring is 25%. But in reality, the percentage of myopic children seems to exceed this number. This is the environmental factor that will be discussed below. (2) Environmental factors Environmental factors are non-genetic, acquired factors that can cause myopia to occur. Specifically, they refer to excessive eye use at close range and improper eye hygiene. Poor pencil grip: Poor pencil grip is the “culprit” of myopia, and proper pencil grip is a prerequisite for good eye habits. Let’s compare the difference between the pencil grip posture of the left and right figures. According to the left posture of holding a pen, we can clearly see the pen tip and paper; according to the right posture of holding a pen, from above is not visible pen tip, because it is blocked by the thumb, in order to see the pen tip, only the head side over, or even stick to the edge of the paper to see clearly. This is artificially “creating myopia”! Animal studies have confirmed this out-of-focus induction of myopia. Parents often blame their children for not being able to hold their heads up, writing with their bodies tilted, and using “back braces” to force their bodies to straighten, but have you ever thought that the real “killer” is hiding at home? To improve reading and writing posture, start by correcting your pencil grip! ② The factor of continuous eye time is too long: many primary and secondary school students get a favorite reading material, or in order to complete homework, prepare for exams, etc., often uninterrupted reading for hours, or even stay up late. This is a very unscientific eye habits, not only mental fatigue, but also make the eyes in a state of continuous regulation of tension, congestion, dryness, resulting in visual fatigue, very easy to induce the occurrence of myopia. Therefore, experts emphasize that scientific eye use is to read 45-50 minutes to rest 10 minutes, during the break should be far away, do outdoor sports, badminton, table tennis and other items as the best. ③ Factors of poor learning environment: poor learning environment, lighting does not meet the requirements, too strong or too weak light is also a major factor in the formation of myopia. Moderate lighting is needed for reading and writing. Too strong light makes the eyes excessively stimulated, easily inducing visual fatigue: too weak light is a decrease in the contrast of the visual field, forcing the distance between the eyes and the book to shorten, inducing myopia. Scientific lighting is double lighting, that is, in 2 to 3 meters from the book there is an appropriate brightness diffuse lighting (such as fluorescent lamps on the ceiling) at the same time, in 0.5 meters from the book and then placed a lamp, to ordinary incandescent lamps is better. Do not blindly believe in the advertising of various eye lamps, there is not enough scientific research to prove that eye lamps can effectively prevent myopia. ④ Other factors: including the influence of intrauterine period, the influence of physical factors, the influence of nutritional factors and so on. It should be noted that taking cod liver oil and beta-carotene is a way to supplement vitamin A for patients with night blindness (vitamin A deficiency sign), not myopia! Do not take drugs blindly, as long as the diet is balanced and not partial, children’s daily intake of micronutrients from food is sufficient. 4.How is myopia classified? A: Myopia can be divided into simple myopia and pathological myopia, the former is mainly caused by bad eye habits, the latter is genetically dominated, such as myopia reaches 700 degrees at the age of 4, and can reach 1000 degrees at the age of 8, and accompanied by significant fundus retinal changes. Most myopic patients belong to the former, and the former can be divided into low, moderate and high myopia by 300 degrees and 600 degrees. 5.What is pseudomyopia? How can I tell if it is pseudomyopia? A: When parents hear that their child is myopic, they often say, “Is it pseudomyopia or true myopia?” The introduction of the doctrine of pseudomyopia reflects the eagerness to correct myopia in China, while not excluding certain artificial or commercial factors. In fact, this doctrine, which became popular in China in the 1960s, is not a scientific certainty. The so-called pseudomyopia is only a very small percentage (probably no more than 3%) of adolescent myopia: a myopic phenomenon, but not essentially myopic. It is a temporary change in refractive state caused by excessive eye use at close distances and adjustment spasms, producing the same symptoms of blurred vision as nearsightedness when looking at a distance. So how can you tell if myopia is real or not? The easiest and most reliable way is to have your pupils dilated. If the result of the eye exam shows no prescription or mild farsightedness after the pupil dilation, then it can be said that it is “pseudomyopia”; if it still shows myopia, then it is true, and there is no need to deceive yourself. You can also use ultrasound A to measure the length of the eye axis. Generally speaking, myopia is an eye axis that is longer than normal, and annual measurement of the eye axis can help you understand the progress of myopia. 6. Why are children with myopia prone to ocular exotropia? What is meant by exotropia? A: Under normal circumstances, the human eye will make three responses simultaneously when looking at the near: pupil narrowing, lens adjustment, and binocular assembly. As mentioned above, myopic eyes require less accommodation than normal eyes, but still require a sufficient amount of binocular accommodation (or else diplopia will occur), so the accommodation/concentration balance is lost and the eye position tends to deviate outward, called emmetropia. Ectropia is not manifested when both eyes are looking at the same time, but can be induced by covering one of the eyes and breaking the binocular fusion. A small amount of emmetropia is normal, while a large amount of emmetropia is harmful to the visual function of both eyes, and may even develop into dominant emmetropia, which should be treated with early intervention. 7.What is visual acuity and how to check it? A: Visual acuity, also called visual acuity, is the eye’s maximum ability to distinguish the fine structure of objects. Medically, it can be divided into naked vision and corrected vision. Naked vision, as the name implies, refers to the vision that an individual has without any optical lens correction. Corrected vision refers to the visual acuity that can be achieved after correction by various optical methods, including frame glasses, contact lenses, excimer myopia laser surgery, etc. It is best to use artificial illumination when examining visual acuity, with distance vision examination at 5 meters and near vision examination at 30 centimeters, using different visual acuity tables respectively, the former being more commonly used in clinical work. 8.What is considered normal visual acuity? A: Under normal circumstances, when a person is 3 years old, the eye is not fully developed, in a farsighted state, its normal naked eye vision is 0.6; just entered the school age, still in a mildly farsighted state, the normal naked eye vision is 0.8 ~ 1.0. Thus, it can be seen that the medical sense of the normal visual acuity of children is not necessarily 1.0, not to mention 1.2, 1.5 or even 2.0. higher than 1.0 visual acuity is called super The visual acuity higher than 1.0 is called hyperopia, because the refractive medium is transparent and the retinal function of the fundus is good, and the resolution of objects can reach more than 1.0. However, hyperopia is not what we are looking for in optometry, and people with hyperopia do not have any advantage in quality of life compared to normal vision people except for taking advantage when applying for pilot jobs. Medical science is more concerned with corrected visual acuity, and normal corrected visual acuity for adolescents is generally above 1.0. Corrected visual acuity below 0.8 is called amblyopia, which is a disease with limited development of the visual system and requires early medical treatment. 9.What is optometry? A: In layman’s terms, it is to check the refractive state of the eye. The refractive state of the human eye is divided into myopia, hyperopia, astigmatism, etc., which can only be accurately known through optometry. Optometry is also divided into objective optometry and subjective optometry, the former does not require the subject to identify the visual marker, through the judgment of the optometrist can be completed, while the latter requires the cooperation of the subject and optometrist to complete together. Generally speaking, objective optometry comes first, subjective optometry comes second, and the final prescription is based on the results of subjective optometry. As mentioned earlier, the human eye is a highly sophisticated camera, capable of seeing both near and far. When myopia increases, no matter how the “lens” is focused, seeing far away is blurred. But it is worth noting that when children just appear low myopia, they can compensate for refractive error by squinting to increase the depth of focus, and can barely see as far away as the blackboard, but this is at the cost of visual fatigue, the results can be imagined. Therefore, parents should never make subjective assumptions about their children’s myopia, nor should they wait until their children can’t really see before coming to the clinic. Experts recommend that children and adolescents have a dilated eye exam at least once every six months. (A friendly reminder to avoid the summer and winter peak periods for optometry) 10.What is dilated optometry? Why do teenagers need to dilate their pupils? A: Dilated optometry is to dilate the pupil after the optometry? Not exactly correct. The purpose of pupil dilation before optometry for children and adolescents is to relax the ciliary muscles and stabilize the refractive state for accurate optometry, not just to dilate the pupil. Usually the dilation agents used are rapid dilation agents, such as Double Starlight and Medrolite eye drops, which have a rapid onset of action and last for 6-8 hours, generally not affecting school the next day, and are suitable for children aged 6 to 16. Blurred vision and photophobia are normal after use, so there is no need to worry about any other side effects, and they are harmless to children. Individuals with high hyperopia, astigmatism, internal strabismus, and children under 6 years old with strong regulation, doctors usually recommend using atropine eye ointment (water) to dilate the pupil, which needs to be used three times a day for three days, and then optometry, the duration of the drug is usually 2 weeks, and some patients need to come back for a second test after 2 weeks to determine the treatment method. 11.What is computerized optometry? Computerized optometry results are reliable? A: Computerized optometry is a product of modern scientific development, can automatically analyze the refractive state of the eye, fast and easy. However, computerized optometry is affected by the stability of the instrument, the skills of the examiner, the degree of cooperation of the examinee, eye adjustment and other factors, the accuracy of the results is not stable, especially for children, the error is relatively large. The results of computerized optometry for children and adolescents after pupil dilation can be used as a reference for further accurate optometry, but are far from being the final prescription. The correct medical optometry steps for children and adolescents should be: pupil dilation – computerized optometry – shadowing optometry – subjective optometry. 12.How can I read the optometry prescription? A: Spherical lens is what we often call “degree”, its medical unit is “D”, 1D = 100 degrees, “-” represents myopia, “+ ” represents farsightedness. In the table, the spherical lens of the right eye shows -1.50D, i.e. 150 degrees of myopia, and similarly, the left eye shows -1.75D, i.e. 175 degrees of myopia. The column lens is what we often call “astigmatism”, the unit is also “D”, its reading method is similar to the spherical lens, except that the axial direction of astigmatism may confuse you, but you just know that it represents the direction of the placement of the astigmatic column lens. “Why is the axial difference between the two eyes so big”, “the axial difference between the front and back optometry is so big” and other issues are more complicated, not a few words to explain, parents do not need to look deeper. The last is the corrected visual acuity, 1.0 means that with such a pair of trial lenses, the subject can achieve 1, 0 visual acuity. The summary is: right eye 150 degrees myopia, 50 degrees astigmatism, axial in 175, can be corrected to 1.0; left eye 175 degrees myopia, 25 degrees astigmatism, axial in 5, can be corrected to 1.0. simple it! Take your own optometry report and try it.