What is the effect of laser surgery for myopia?

It is estimated that there are at least 654.38 billion myopia patients in the world, and myopia research has a history of hundreds of years. In recent years, the most controversial treatment for myopia is corneal laser surgery. The British "Sunday Times" reported that "the government's medical supervision department is preventing the national medical service system from performing eye laser surgery because of concerns about the long-term safety of patients". The American Journal of Ophthalmology also pointed out that "the failure rate of this kind of ophthalmic surgery is110, not11000 as stated in most advertisements." Surgery may also cause complications, so patients must undergo corneal transplantation. These news also caused an uproar in China, which triggered a hot discussion about "the safety of ophthalmic laser surgery". People who have complications after laser surgery have come out to talk about it, and some media have reported that "myopia surgery, which was popular 0/5 years ago, left sequelae due to limited technical level, and now it has been reworked". Some medical workers came out to refute the British research department's statement and explain the safety of the operation to patients. So, what is myopia laser surgery? What is its success rate and safety? What is the long-term effect? Should I do this operation or not? Welcome to discuss. There are many ways of excimer laser surgery, which is generally called excimer laser surgery. Its full name should be excimer laser refractive corneal surgery, which mainly includes three kinds of surgery: (1) excimer laser keratectomy (PRK), which is the earliest method used in clinic. At present, PRK is considered as a safe and effective method to treat moderate and low myopia, hyperopia and astigmatism, but it is rarely used because of its postoperative pain, refractive regression and other complications. (2) excimer laser in situ keratomileusis (LASIK), which is the mainstream surgery at present. It cuts the stromal layer under the corneal flap, maintains the integrity of corneal epithelium and anterior elastic layer, and avoids most complications of PRK. It is characterized by broadening the correction range of myopia, no pain during and after operation, rapid recovery of vision and no macular degeneration on the cornea. During the operation, a thin corneal flap with pedicle was cut out on the cornea with a micro-knife, the flap was opened, laser cutting was carried out under the flap, and then the flap was restored to its original position. This can be used for low, medium and high myopia. LASIK also has defects caused by corneal flap, such as corneal flap wrinkling, displacement, epithelial implantation under corneal flap, astigmatism and excessive cutting, which leads to corneal dilatation and keratoconus. The use of LASIK is also limited for relatively myopic patients with high and thin cornea, but it is better to choose LASIK for patients with high myopia with thick corneal flap. (3) Laser in situ keratomileusis (LASEK) is an improved operation of PRK. The corneal epithelial flap was made by soaking the corneal operation area with laser or low concentration alcohol, and the tissue under the epithelial flap was cut by laser. When the corneal epithelial flap is reset, it is still necessary to cover its surface with a layer of contact lenses. After LASEK, the pain is obviously relieved compared with PRK, and the flap is thin, which can be used for patients with relatively thin cornea and large pupil. As a corneal flap, LASEK has no complications of LASIK, which shortens the healing time of corneal epithelium after PRK and reduces the degree of pain reaction and corneal opacity. However, the corneal epithelial flap injury and edema during operation are the same as PRK, and the speed of visual recovery and refractive stability after operation is slower than LASIK. Therefore, it is mainly suitable for patients with thin cornea, occupational characteristics prone to eye trauma leading to corneal flap displacement or other patients who are not suitable for LASIK surgery. In addition, not long ago, Ioanes, a Greek physician, took the lead in proposing Epi-LASIK surgery. Epi-LASIK can combine the advantages of LASEK and LASIK and avoid their disadvantages. It uses a rotating epithelial knife to "make a movable epithelial flap" on the corneal epithelial layer, with a thickness of only more than 50 μ m, instead of soaking it in alcohol like LASEK. At the same time, the corneal thickness can be preserved to the greatest extent, and the postoperative irritation symptoms are also very small, the probability of corneal opacity is less than PRK, and myopia subsides. Not all myopia patients are suitable for excimer laser surgery. Generally, excimer laser surgery can only be considered if the following conditions are met: 18 years old, healthy in mental state, and willing to take off glasses; No active eye disease; In the last two years, the degree of myopia has been relatively stable, and it has deepened by no more than 50 degrees every year; If wearing contact lenses, soft lenses should be removed for 2 weeks, and hard lenses should be removed for more than 4 weeks (glasses can be changed for preoperative examination); After examination by the doctor, all the indexes of the eye meet the requirements of the operation; If it is the second operation, the interval between LASIK and PRK should be 3 ~ 6 months, 1 year. If hyperopia, myopia and astigmatism occur after penetrating keratoplasty, the interval should be greater than 1 year; A disease that has no surgical restrictions on the whole body. Excimer laser surgery is not suitable for people with acute active inflammation, dry eye, eyelid insufficiency, glaucoma, cataract, uveitis, retinal detachment, ischemic eye disease, herpes simplex and other viral eye diseases, as well as diabetes, collagen diseases (lupus erythematosus) and other systemic diseases. ), rheumatoid arthritis, gout, mental illness, AIDS, and people with certain diseases that affect wound healing or safety are the focus of public attention. The first choice is still to wear glasses to correct myopia. There are usually three methods: 1. Lens correction: including frame glasses and contact lenses; 2. Corneal refractive surgery: radial keratotomy (RK), excimer laser keratectomy (PRK), excimer laser in situ keratomileusis (LASIK), etc. 3. Intraocular refractive surgery: clear lens extraction and intraocular lens implantation in phakic eyes. It should be pointed out that, considering the factors of safety, simplicity, economy and practicality, ophthalmology believes that for most people, the first choice to correct myopia is to wear glasses. If the patient is going to choose excimer laser surgery, the most concerned issue is the safety of the surgery. Objectively speaking, the current excimer laser surgery is relatively safe. Compared with the earliest radial keratotomy with diamond knife to treat myopia, its safety has made a qualitative leap, which has been fully proved by a large number of clinical practices in 10 years. It can be said that laser surgery for myopia has been relatively mature in China. However, the success rate of any operation cannot be 100%. Just as contact lenses are easy to be infected and harmful to vision, trauma caused by broken lenses of frame glasses is also one of the causes of blindness. According to the article in American Journal of Ophthalmology, the failure rate of this kind of ophthalmic surgery is110, and most domestic refractive surgery experts hold different opinions. Of course, good surgical equipment, skilled operation and rich experience of operators and good cooperation of patients are the basis of high safety of surgery. Any operation is risky, and myopia laser surgery can't completely avoid complications. The most common complication is overcorrection or undercorrection, which should be observed for a certain period of time and re-operated as appropriate; Some people may have glare, that is, a light spot is regarded as a light cluster or halo at night, and there is a slight edema reaction between corneal tissues after operation or a large pupil at night, and its edge is close to the surgical edge, which can be gradually reduced. Keratoconus appears in people who have this potential or whose cornea is too thin after operation; Because of poor gaze on the target, eccentric cutting may occur, or the central island may appear due to the action of water vapor vortex on the corneal surface; After PRK and LASEK surgery, corneal Haze and hormonal ocular hypertension may occur due to long-term use of anti-Haze drugs. LASIK has complications related to corneal flap, such as foreign body under the flap, corneal flap displacement and dissolution, increased astigmatism, dry eye and so on. The most serious is the infection of corneal wound during operation. Although it rarely happens, it is the direct cause of blindness, so strict surgical disinfection system and good hygiene habits of patients are very important. After operation, you should also check your eyes regularly, paying special attention to the changes in macular area and peripheral retina, so as to plan ahead. Strict medication and postoperative review are important links. Some patients have unsatisfactory postoperative results or complications, which are caused by not strictly following the doctor's advice. Therefore, doctors should pay special attention here to remind patients to pay attention to postoperative matters. After LASIK 1 ~ 2 hours, eyes usually have sour tears and foreign body sensation, and the symptoms basically disappear after two or three hours. If the symptoms of eye pain are obvious, we must pay attention to distinguish between eye skin pain and eyeball pain. If it belongs to the latter, you should immediately consult an ophthalmologist to rule out the possibility of infection and corneal flap displacement. When eye symptoms appear on the day of operation, you can close your eyes and rest. Don't take off the transparent blindfold at will, and don't squeeze or rub your eyes. The next day, the doctor took off the transparent blindfold, checked his vision, cornea and refraction, and then went to the hospital for reexamination, which was 3 days, 7 days, 1 month, 3 months, half a year and 1 year after operation. Especially in the early postoperative period, doctors can adjust the medication in time according to the reexamination results, which is also an important link to ensure the success of the operation. Patients should also be told to avoid going to places with heavy smoke and dust within one week after operation, eat less spicy food, do not put makeup on their eyes, and avoid water and fine particles entering their eyes. Many people recovered their normal vision on the second day after surgery, but their vision fluctuated in the next few days. Some people's vision gradually returned to normal, mostly stable for two weeks, and finally recovered in March-June. Antibiotics can be taken orally for three days after LASIK to prevent infection; Antibiotic eye drops, hormone eye drops and eye drops for promoting corneal epithelial growth, lubrication and anti-drying should also be given, generally not exceeding one month. For a month, you should use your close-range fine vision less (including watching computer and TV). After the operation, due to the change of refractive state, some people will find it difficult to see things at close range in the early stage and get tired easily. If work and study cannot be avoided, it is necessary to have more intervals, blink more and have more rest, and the general symptoms will gradually disappear with time. In addition, we should pay attention not to swim for a month, avoid diving and intense antagonistic exercise, so as to avoid hitting the eyes, causing eye trauma, corneal flap displacement or even loss. When you have glare symptoms, you should wait until the symptoms disappear before driving at night. Health Economics of Ophthalmic Laser Surgery Excimer Laser Surgery Different surgical methods \ Different hospitals have different prices. For example, the cost of LAISK surgery in most hospitals is 6000 ~ 8000 yuan, but some only need 2000 yuan, and some even need 800 yuan. What needs to be vigilant is that the cost reduction is limited. Some hospitals are very cheap because they use equipment and materials that have long been eliminated abroad. They must have outdated technology or quality problems, and the surgical effect can't be the same. Therefore, we must choose a large hospital with good reputation and guaranteed technology. In recent years, the rapid development of laser treatment of myopia in China is unprecedented. But at present, there are two extremes in domestic public psychology: the first is the effect of apotheosis surgery. At present, laser surgery is not perfect, especially the correction with the height above 1200 degrees, and its predictability, safety and postoperative stability are obviously insufficient. Moreover, for pathological myopia, the surgical requirement is only to improve the far vision of the eye chart, but it ignores that the laser is only optical correction, which is not helpful to the existing lesions of the fundus. Another opposite view is that laser surgery for myopia is completely denied, that is, the so-called "palliative", but another fact is ignored: for moderate and low myopia, more than ten years of practice has proved that laser surgery is effective, stable and reliable. In addition, some patients who had surgery before 15 really need to "rework" now, but not all patients who have had surgery need it. There are two main reasons for "rework": First, radial keratotomy (rk) in the past was not as safe as PRK and LASIK. Secondly, as we all know, not all myopia patients can use RK surgery. The pathology of myopia is different, especially high myopia (above 600 degrees), which can be divided into simple type and pathological type. Simple high myopia can be treated by surgery, and pathological high myopia needs scleral reinforcement before operation. Myopia exceeding 1500 degrees requires intraocular lens implantation. In the past, all myopia used the same surgical method, which was inappropriate. In recent years, the methods and equipment of laser surgery for myopia have been greatly improved, especially the appearance of excimer laser personalized keratectomy (ORK) guided by corneal wavefront aberration, which makes the shape of laser cutting more in line with the optical characteristics of cornea, with better effect and fewer complications. In addition, the processing ability of ophthalmologists has been significantly improved, so the "rework" of surgery in recent years should be less and less. In a word, the practice of these years has proved that the safety and effectiveness of laser surgery for myopia have been greatly improved, and it is not advisable to hold a completely negative attitude. Of course, this operation has only been carried out for more than ten years, and the long-term effect and safety are still under further study. Therefore, it is unwise to think that laser surgery is perfect for myopia without any risk. Only by getting out of the misunderstanding, studying calmly and deeply, and evaluating scientifically and objectively is a rational attitude. In particular, it needs to be reminded that there are still cases of pure profit-seeking and abuse of this technology in some places in China. Therefore, it is particularly important for patients to carefully consider before choosing surgery, weigh the advantages and disadvantages, and choose regular medical institutions and experienced doctors. Links about excimer laser treatment of myopia 1983 Dr. Stephen of Columbia University in new york tried excimer laser for the first time in refractive surgery and began experiments on animal corneas. In the early 1990s, FDA began clinical trials of excimer laser keratectomy (PRK). At that time, the scope of treatment was mostly between moderate and low myopia. 1995, FDA approved PRK surgery for moderate and low myopia (within 600 degrees); 1999 LASIK is used for the clinical treatment of high myopia, hyperopia and astigmatism. 1992, China introduced quasi-laser to carry out PRK, followed by LASIK. Compared with the earliest radial keratectomy with diamond knife, excimer laser surgery has the advantages of less injury, high accuracy, strong foresight, less complications and wide indications. By cutting the corneal tissue in the central area to flatten it, myopia, hyperopia and astigmatism can be corrected. If hyperopia is treated, the corneal tissue around the periphery is cut in a circular way to make the cornea in the central area steeper; If the cutting surface is oval, astigmatism can be corrected. Myopia (or hyperopia) and astigmatism can be corrected at the same time. The thinning of the central area of the cornea can get the effect of wearing concave lenses, and the thinning of the periphery can get the effect of wearing convex lenses. Of course, excimer laser surgery is only a myopia correction method. It only "embeds" the degree that needs to be corrected in the cornea, and it cannot change the pathological process of myopia to cure myopia.