Nearsightedness Myopia is also called short-sightedness because it is an eye that can only see near but not far. When the eye is at rest, parallel light from an infinite distance is refracted by the refractive system of the eye and assembled into a focal point in the retina, while the image is not clear in the retina. The distance vision is significantly reduced, but the near vision is still normal. The following analysis and discussion are made on the current treatment and prevention of myopia.
I. Treatment of myopia
1, the physical correction of myopia correction principle for the use of myopic eyes, the total refractive power of the eye is too strong, like focusing on the retina in front; with the use of concave lenses placed in front of the eye to make light before entering the refractive system of the eye scattered, so that the image into the retina.
1.1 Frame glasses correction
1.1.1 Ordinary frame glasses correction method is now relatively mature, is the majority of people to correct myopia. Before dispensing glasses, the first thing is to check the true degree of myopia through the optometry. For adolescents prescription optometry should be performed under ciliary muscle paralysis to control the regulatory effect and exclude pseudomyopia. The principle of prescription should be to take the lowest degree lenses that can also correct the myopic eye to the best vision. It is also important to be able to maintain comfort and binocular vision function. The advantages are: economic, safe, but the disadvantages are: is to affect the natural face, the possibility of inhibiting the development of the nasal bone for adolescents, while the imaging quality is not high, the visual effect is poor, the field of vision becomes relatively small, for myopia control is also difficult to play the effect.
1.1.2 Many scholars have proposed the use of multifocal lenses to control the growth of myopia in adolescents, the principle of which lies in the fact that the lenses are specially set up with a near and middle use area, which is underglazed, and unlike ordinary spherical monofocal lenses, the design obviously reduces the regulation of excessive use when reading with distant lenses, thus relieving the visual fatigue caused by long-term reading and alleviating the further growth of myopia. Clinical trials conducted by Essilor at the Hong Kong Polytechnic University in China in the 1990s showed that the use of this lens was effective in reducing myopia growth in adolescent students; however, subsequent observations at the Wenzhou Medical College found that this method was not effective in controlling myopia growth in students because of the presence of aberrations in the lens design, which affected the quality of retinal imaging; current: multicenter, long-term clinical observations is still in progress and we await the final results.
1.1.3 The myopic regression lens, a new design of lens that has emerged in recent years, is also recognized by many ophthalmologists. The concept of this design believes that when a person reads at close distance, not only the problem of adjustment should be considered, but also the problem of collection should be accompanied, the designer quoted the theory of Professor Xu Guangdi, a famous optometrist in China: “looking in is equal to looking away, learning is equal to treatment”; the design of the lens takes fully into account the eye of a person when looking away and looking at close distance In the design of the lenses, the physiological condition of the eyes is taken into account, in addition to the design of the lower light area for near use to reduce the adjustment; at the same time, prisms are used in front of both eyes to reduce the collection problem when reading, which solves the adjustment problem caused by the collection when reading, and achieves the purpose of looking into the distance. However, some domestic experts believe that this design is not ideal, mainly because the lens design is not specific to the individual, because each person does not need the same adjustment and collection when reading; at the same time, a few optometrists also believe that the use of prisms destroy the clarity of the retinal imaging, for the control of myopia is not beneficial. So, we will see how myopic regression lenses are used and how some of the problems will be improved.
1.1.4 It is worth mentioning that different types of small-hole glasses for myopia appeared in the world in the nineties. It is already well known that pinhole lenses can increase vision. Recent literature reports that pinhole diameter of 0.5 mm, for example, can keep the visual acuity around 0.5 for various refractive errors of 5.0D. However, the pinhole only increases the image depth and thus the visual acuity, and has no preventive effect on myopia. In addition, although these lenses are opened a lot of small holes, students wearing such glasses in class, with the observation distance changes in the distance between the eyes also constantly changing, even if the small hole open more can not keep both eyes monovision. Only the dominant or primary eye is used for monocular vision, and the other eye is suppressed. The resulting visual disturbance is secondary, but most importantly, the development of the eye’s vision will be affected if one eye is in a constant state of suppression during the early adolescent period. Therefore, the use of small hole lens to treat myopia is ineffective and harmful, should not be tried.
1.2 Corneal contact lenses Contact lenses also use the principle of concave lenses to disperse light to correct vision. Wearing contact lenses can increase the field of vision, have a better cosmetic effect, and can make the refractive difference between the two eyes significantly reduced, so as to maintain the visual function of both eyes. Corneal contact lenses can be divided into two types: soft and rigid.
1.2.1 Soft lenses are more available on the market, relatively simple to fit, comfortable and good; better vision correction; however, they are not accepted by the majority of adolescent myopia patients due to unsatisfactory correction of astigmatism, low oxygen permeability, and easy to adsorb protein precipitation, which causes a variety of complications;
1.2.2 For adolescent myopia, RGP (Rigid High Oxygen Permeable Corneal Contact Lens), which is favored by domestic and foreign optometrists for its excellent oxygen permeability, stable lens material, and not easy to adsorb protein precipitation, can not only obtain good visual effects, but also massage the cornea to prevent myopia from continuing to develop (several experts in China have done corresponding clinical reports). It is the only ophthalmology project among the 100 promotion projects of the Ministry of Health of China for ten years, and it is certainly a big development direction in the prevention and treatment of youth myopia in the future. However, it must pay attention to cleanliness and hygiene, disinfection maintenance and frequent replacement as required.
1.2.3 Corneal shaping (ok lens) for myopia
Orthokeratology is a non-surgical treatment for myopia that has been developed in recent decades by wearing specially designed oxygen permeable rigid corneal contact lenses (RGP) to increase the radius of curvature of the corneal surface and reduce the refractive power of the cornea. As RGP lenses are updated, their safety, effectiveness and speed are further improved.
Advantages: nighttime wear, daytime removal, sports are not affected; aesthetic; can correct myopia less than 500 degrees, astigmatism less than 150 degrees (with the current development of corneal plastic technology, there have been many reports of 600 degrees or even higher diopter wearing OK lenses); can be worn by people over 6 years old, less age restrictions.
The treatment is currently used by many commercial institutions, over-exaggerating the efficacy of the use of OK lenses, is the patient blindly believe that can reduce myopia, and in the informal operation of the expansion of the adaptation of the population, so that patients produce irreversible damage to the cornea. OK lenses can not be worn after a short period of time frame glasses; lens cleaning and loading and unloading the same degree of difficulty as soft corneal contact lenses; with the initial period of keratitis often occurs. Therefore, it is necessary to go to a professional eye care institution to avoid adverse effects on eye health.
1.3 Surgical correction of myopia
1.3.1 Radial keratotomy (RK) This method was first tried by Soviet scholar kranov (1970). It has now been reported in several places in China. After the incision of the corneal surface, under the action of normal intraocular pressure, the peripheral part with reduced tension expands outward, the central part of the cornea becomes relatively flat, the refractive power decreases, the focal point shifts backward, and the position of the retina is newly adapted, thus reducing its myopia. It is generally accepted that 3.00D myopia can be corrected. The advantage of RK is that the procedure is simple and does not require complex instruments; the disadvantage is that complications may arise and there is a risk of postoperative trauma that may rupture the eye. Since the long-term results of this method are not yet certain, and the indications and contraindications have to be strictly selected, and there is a possibility of surgical complications. It is currently being replaced by laser keratomileusis.
1.3.2 Excimer laser keratomileusis (Photorefractive keratectomy, PRK for short): The principle of the procedure is to apply an excimer laser to cut the central anterior surface of the cornea, i.e., to remove the preelastic layer of the epithelium and the superficial stroma, so that the curvature of the anterior surface of the cornea is reduced. The advantages of PRK are simple surgery, good surgical results, and few complications; the disadvantages are that expensive instruments are needed, painful for 3-5 days after surgery, and the need for long-term medication.
1.3.3 LASIK surgery i.e. Excimer laser in situ keratomileusis (Laser in Situeratomileusis): the surgery is a treatment surgery for high myopia using new and more complex equipment. The procedure is performed using automated micro lamellar cutting, which involves cutting an 8 mm diameter, 0.16 mm thick lamellar flap on the corneal surface, flipping the flap, applying excimer laser computer-controlled multi-step zoned corneal stromal cutting, and finally resetting the flap. This approach preserves the integrity of the corneal epithelium and anterior elastic layer, and the 193 nm excimer laser is used to cut the corneal stroma, avoiding the occurrence of postoperative haze clouding. This surgical approach is a major innovation in the surgical treatment of high myopia and can correct up to 3500 degrees of myopia. Many patients have higher postoperative visual acuity than their preoperative best corrected visual acuity with lenses and fewer complications, and its efficacy has attracted widespread attention. However, this procedure is sophisticated, expensive, requires high surgical technique and a sterile surgical environment, and can only be performed in large hospitals with good conditions. Currently, LASIK has become the most commonly used refractive surgery method and is widely used worldwide to remove glasses for many myopic and farsighted patients.
1.3.4 Laser thermokeratoplasty (LTK): The procedure involves direct irradiation of the peripheral corneal stroma with a holmium laser, which causes the collagen fibers of the cornea to crumple, the middle cornea to bulge, and the refractive power to increase, and is used to treat farsighted eyes of up to 300 degrees. The disadvantage is that the scope of treatment is limited and the results are sometimes regressive. This method is currently used in clinical practice.
1.3.5 Internal corneal stromal ring (ICR): In this procedure, two radial 2/3 depth incisions are made in the periphery of the cornea and two PMMA ring segments (150 degrees in arc length, implanted in the stroma of the cornea, located 6.8 to 8.1 mm from the center) are inserted into the corneal stroma. The two small fragments placed into the cornea are actually the size of a needle tip and are hydrogel-like substances that do not cause any foreign body sensation in the patient after surgery and have the advantages of predictability, safety, stability, and reversibility and interchangeability. If the patient is not satisfied with the results of the procedure, the implanted ring segment can be replaced or removed. After removal of the ring, the curvature of the cornea can be restored to its original preoperative condition. It is currently in the clinical trial stage and is not yet widely used in clinical practice.
1.3.6 Phakic intraocular len (Phakic IOL): The procedure involves making an incision near the corneal limbus, implanting an IOL into the anterior or posterior chamber of the eye, and then closing the incision. The disadvantage is that intraocular surgery may produce complications and the cost of surgery is high. It is currently used in clinical practice and is more suitable for very high myopia.
1.3.7 Phacoemulsification & Intraocular len (Phaco + IOL): The procedure is performed by making a small incision at the corneal limbus and then aspirating the lens after ultrasound emulsification and implanting a calculated IOL. The advantage of Phaco+IOL is that the procedure can treat both cataract and myopic and hyperopic eyes; the disadvantage is that the procedure is intraocular and may result in complications. This method is now widely used in clinical practice.
1.3.8 Duplex IOL implantation (Piggyback+IOL): The same procedure as above, except that two IOLs are implanted to correct patients with very high hyperopia combined with cataract.
1.3.9 Posterior scleral reinforcement: This procedure uses medical silicone sponge, allograft sclera or broad fascia as protective reinforcement material to reinforce and fuse the posterior pole sclera to support the posterior pole of the eye and prevent progressive expansion of the posterior pole and progressive lengthening of the eye axis, thus reducing the degree of myopia to a certain extent. At the same time, neovascularization is formed after surgery, which enhances blood circulation in the choroid and retina, excites the optic cells, activates bioelectricity, and improves visual acuity. This procedure is suitable for controlling the progressive lengthening of the eye axis in high myopia, and is especially important for adolescents with high myopia whose eye axis length exceeds 26 mm and whose myopic refraction deepens and develops more than 1.00D per year.
2, other methods of myopia treatment Pseudomyopia is due to the fact that the eye still maintains a certain degree of regulation when looking at a distance. In other words, it is a refractive state in which the eye relaxes slowly when it changes from looking near to looking far, and it increases with the prolongation of the time spent looking near and the increase of the degree of regulation, and decreases or disappears with the degree of looking far and the relaxation of regulation. Therefore, pseudomyopia has the characteristics of disappearing if treated (including rest) and recurring if not treated, and various methods may have certain effects, but all effects are not lasting. Therefore, the following principles should be used in the treatment.
①It is not harmful to the eye, and even long-term application has no effect on visual development.
Because pseudomyopia can improve on its own, the method used should be scientifically based, and the objective method should be used to prove that there is indeed a relaxing effect on the regulation, and it is unreliable to assess the efficacy only by the improvement of visual acuity.
③Simple and easy to use, can be widely promoted.
The methods currently used are.
(1) Using various methods to increase visual excitability and lower the visual threshold: such as qigong, cold water bath, taking excitatory drugs, etc. This type of therapy can not only improve the distance vision, it is reasonable that their visual acuity should also be improved, but is not the ideal treatment method.
(2) Topical medication: such as atropine, which has a fast and obvious relaxing effect, is a unified method to identify true and false myopia. However, these drugs are inevitably combined with the side effects of difficulty seeing close and photophobia. Recent studies have shown that atropine can effectively organize further increases in myopia by organizing the M receptors present in scleral tissue, thus suggesting that the drug could be used as a myopia treatment. However, the more obvious side effects make the drug difficult in clinical application, and a new similar drug, pirenzepine, is currently in clinical trials abroad.
(3) Traditional Chinese medicine: According to traditional Chinese medicine, myopia is caused by damage to the liver and kidneys. In the Chinese medicine, it is believed that myopia is caused by damage to the liver and kidney. The five viscera of Suwen, “The liver receives blood and can see”. The Ling Shu, a treatise on the generation of the five viscera, states that “the blood of the twelve meridians, three hundred and sixty-five paths, all go up to the face and go to the orifices, and the essence of the Yang goes up to the eyes and becomes the eyes”. If liver and kidney yin is deficient, the vision will be dim and blurry, with insomnia, forgetfulness, lumbago, dry eyes, red tongue, thin white tongue coating and thin pulse. Chinese medicine treatment is to nourish the heart, nourish the liver and kidney, and open the meridians as the main rule. The treatment is to nourish the liver and kidney, benefit the qi and nourish the yin. The formula is Qiju Dihuang Wan medical grade plus or minus, medicine such as wolfberry, chrysanthemum, Shu Dihuang, Cornus officinalis, yam, zedoary, danpi, poria, etc.. Acupuncture treatment can also be used to tonify the liver and kidneys, benefit the qi and brighten the eyes, and open the meridians and activate the channels. Chinese medicine, such as acupuncture, food therapy with the treatment of myopia, will greatly improve the effectiveness of treatment. The kind of ear acupuncture currently being done everywhere in society also belongs to a method of Chinese medicine, but must be operated by a professional Chinese medicine practitioner.
(4) Physiological treatment methods: such as far-seeing, fog vision method and crystal health exercises. All of them should have a distant target as the attraction for relaxation and adjustment, and the treatment cannot be carried out in the near environment such as the evening self-study. In 1983, Xu Guangdi designed the binocular combination method to prevent and treat pseudomyopia, which is now known as the xu-myopia control device. It is installed in a 10 × 9 × 3cm3 dark box with two groups of flash bulbs. One group of two lights is located in the line of sight of the two eyes to see far, to simulate the role of the far target, when this group of lights flashing, the observation eye that is self-convergence image, the two eyes to the infinity of the line of sight, according to the joint movement of regulation and collection relationship, in the collection of dispersion at the same time regulation also relaxed. The other group is a single bulb is located in the center of the two synoptic lights, as both eyes look close to the target. When the two groups of light alternately flashing, the observing eye that follows the light suddenly look near do not look far, so that the internal and external muscles of both eyes to work together to achieve the purpose of the near environment to cure pseudomyopia and prevent true myopia.
(5) Eye muscle function exercise: the formation and deepening of myopia, currently more recognized causes are related to prolonged close eye use. The eyes read for a long time, continuous adjustment, and at the same time to maintain the fusion of the two eyes, the internal and external muscles of the eye are under tension. This tension can cause spasm, ischemia, and even atrophy of the inner and outer muscles of the eye, resulting in a decrease in muscle relaxation and a decrease in visual acuity and visual function, which can lead to a further increase in myopia. Exercising the inner and outer muscles of the eye can strengthen the diastolic ability of the muscles, increase flexibility, and improve vision and visual function. It relieves eye fatigue and slows down the growth of myopia. It is worth mentioning that our center has set up a binocular visual function training room, which has a relatively comprehensive set of the above-mentioned equipment for eye exercises and is projected in a multimedia way, making the boring visual function training vivid and interesting, which is more in line with the psychological characteristics of children and adolescents and makes the training more effective In addition, in a broad sense, the pollution of trace elements in the atmosphere In addition, in a broader sense, the pollution of trace elements in the atmosphere, changes in nutritional composition, and ergonomic teaching aids are also objective factors that have been reported to affect the occurrence of myopia in students. However, these factors are minor compared to myopia caused by looking close.
Second, the prevention of myopia According to survey data, China’s adolescent students myopia rate is increasing year by year, the rate of myopia in elementary schools at about 40%, middle school myopia rate at about 65%, high school myopia rate at about 80%, directly affecting their learning, work and future. 1, in order to care for the healthy growth of the next generation, control and reduce the rate of myopia among adolescent students, the following preventive measures should be taken.
(1) classrooms should have good lighting conditions, tables and chairs should be of appropriate height, classrooms should be of appropriate size, the distance of the blackboard should be moderate, not closer than 2 meters, not farther than 6 meters, the distance between the eyes and books when studying should be kept at 30-35 cm, the blackboard should not be reflective, the print used should be clear, the contrast should be sharp, and students should be regularly switched in front, behind, left and right of their seats.
(2) Prevent excessive eye use, do not work at close range for more than 50 minutes at a time, and take a 10-minute break every hour to loosen the adjustment of the extreme eyes, which can prevent myopia.
(3) Do not read in direct sunlight or in the dark, do not lie down, lie on your back or read while walking or riding in a car.
(4) Establish a system of eye exercises, check your eyesight regularly, and take timely and effective measures for students with low vision.
(5) When doing homework in class, you should blink your eyes frequently. When you feel eye fatigue, you should rub your eyes with your hands or close your eyes for half a minute, which will help prevent myopia.
(6) Don’t be picky about food and don’t eat too much sugar.
(7) You must pay attention to personal eye hygiene and keep the area around your eyes clean.
(8) often adhere to the thirteen points around the eyes to apply DZT myopia Kang, one is the eye will not occur visual fatigue; two to ensure that the various normal functions of the eye is not easy to disorders; three can prevent bacteria, viral infections; four to maintain the clarity of the eye’s ability to see things and keep the relative stability of vision will not decline. In addition, it is recommended to pay attention to diet and nutrition, and eat more foods containing vitamin A, such as lamb liver, pig liver, eggs, milk, carrots, vegetables, etc. Promote outdoor active rest and frequent distant vision, 3-4 times a day, at least five to ten minutes each time. Food with vision improvement 2, to protect eyesight and prevent eye diseases, you need to start from many aspects, including attention to nutrition, which can also help to improve vision.
In the daily diet, with the effect of improving vision food are.
(1) foods rich in vitamin A. Vitamin A is closely related to normal vision. If vitamin A is insufficient, the regeneration of retinal red matter is slow and incomplete, and the dark adaptation time is prolonged, causing night blindness in severe cases. If the vitamin A deficiency continues or is insufficient, dry eye disease will develop, which can become corneal softening and corneal ulcers, as well as corneal folds and Bitt’s spots. The best food source of vitamin A is various animal liver, cod liver oil, fish eggs, poultry eggs, etc.; carrots, spinach, amaranth, alfalfa, sweet potatoes, pumpkin, green pepper and other vegetables containing vitamin A can be converted into vitamin A in the body.
(2) foods rich in vitamin C. Vitamin C can weaken the damage of light and oxygen to the lens of the eye, thus delaying the occurrence of cataracts. Foods containing vitamin C include fresh vegetables and fruits such as persimmon pepper, tomato, lemon, kiwi and hawthorn.
(3) Calcium, calcium is related to the composition of the eye, calcium deficiency will lead to myopia. Adolescents are at the peak of growth, the body’s calcium needs relatively increased, if not pay attention to calcium supplementation, not only will affect bone development, but also the developing eye wall – sclera elasticity is reduced, the lens pressure rises, resulting in the front and rear diameter of the eye elongated and lead to myopia. Foods that contain more calcium, mainly milk and its products, shellfish (shrimp), bone meal, beans and soy products, egg yolk and dark green vegetables, etc.
(4) chromium, lack of chromium prone to myopia, chromium can activate insulin, so that the pancreas to play the maximum biological effect, such as the human body chromium content is insufficient, it will make insulin regulation of blood glucose dysfunction, plasma osmolarity increased, resulting in the eye lens, atrial aqueous osmotic pressure and increased refractive error, thus inducing myopia. Chromium is mostly found in brown rice, wheat bran, animal liver, grape juice, nuts are also rich in content.
(5) Zinc, zinc deficiency can lead to visual impairment, zinc in the body is mainly distributed in the bones and blood. Zinc is also contained in the corneal epidermis, iris, retina and lens. Zinc is involved in the generation and transport of vitamin A in the eye, maintaining the normal organization of the retinal pigment epithelium and maintaining normal visual function. Foods that contain more zinc include oysters, meat, liver, eggs, peanuts, wheat, beans, and mixed grains.
(6) pearl, pearl contains more than 95% of calcium carbonate and a small amount of magnesium oxide, alumina and other minerals, and contains a variety of amino acids, such as leucine, methionine, alanine, glycine, glutamic acid, aspartic acid, etc., pearl taste sweet and salty cold, with pearl powder with lobster, amber, etc. into the “real pearl” point eyes can inhibit cataract The formation of.
(7) kelp, in addition to iodine kelp also contains 1/3 of mannitol, sun-dried kelp surface has a thick layer of “white cream”, it is mannitol in kelp, mannitol has diuretic effect, can reduce intraocular pressure, used to treat acute glaucoma has good effect. Other seaweeds such as wakame also contain mannitol, which can also be used as an auxiliary food for the treatment of acute glaucoma. Massage to improve your eyesight Massage to improve your eyesight Massage to improve your eyesight Massage to improve your eyesight Massage to improve your eyesight Massage to improve your eyesight Massage to improve your eyesight Massage to improve your eyesight Massage to improve your eyesight Massage to improve your eyesight Massage to improve your eyesight Massage to improve your eyesight Massage to improve your eyesight Massage to improve your eyesight