When people say "excimer laser surgery", the full name should be "excimer laser refractive corneal surgery", which mainly includes three types of surgery:
(1) Excimer laser corneal surface cutting (PRK), which is the first method used in clinical practice. Laser corneal surface cutting (PRK for short), is the first method used in clinical practice. PRK is now considered safe and effective for the treatment of low and moderate myopia, hyperopia and astigmatism, but it is now less frequently used because of its complications such as postoperative pain and refractive regression.
(2) Excimer laser in situ keratomileusis (LASIK), which is currently the mainstream procedure. It cuts the stromal layer under the corneal flap, keeping the corneal epithelium and anterior elastic layer intact, and can avoid most of the complications of PRK. It is characterized by broadening the range of myopia correction, no pain during and after surgery, fast vision recovery, and no corneal opacity left behind. During the surgery, a thin corneal flap with a tip is cut out of the cornea with a micro-knife, the flap is lifted, laser cutting is performed under the flap, and then the flap is restored to its original position. This can be used for low, intermediate and high myopia, and LASIK also has its share of flap defects, namely flap wrinkling, displacement, subflap epithelial implantation, astigmatism, and over-cutting, resulting in corneal dilatation, cone cornea, and so on. The use of LASIK is also limited for patients with thin corneas relative to high myopia, but for patients with high myopia whose corneal flaps are thick enough, LASIK is preferred.
(3) Excimer laser subepithelial in situ keratomileusis (LASEK), a modified form of PRK surgery. With a laser or a low concentration of alcohol immersion corneal surgery area, made a corneal epithelial flap, laser cutting epithelial flap under the tissue, when the corneal epithelial flap reset, still have to cover the surface of a contact lens. LASEK surgery after the pain is significantly reduced compared with the PRK, coupled with the flap is thin, can be used for corneal thickness of the relatively thin, pupil larger patients.
LASEK does not have the complications of LASIK as a corneal flap, shortens the healing time of the corneal epithelium after PRK surgery, and reduces the pain reaction and the degree of corneal clouding (haze), but the corneal epithelial flap breakage and edema during the surgery are the same as PRK, and the speed of vision recovery and refractive stabilization after the surgery is slower than that of LASIK. Therefore, it is mainly suitable for patients with thin corneas, occupational characteristics prone to ocular trauma resulting in corneal flap displacement, or other patients who are not suitable for LASIK.
Also not long ago, Greek physician Ioannis was the first to propose Epi-LASIK. Epi-LASIK can synthesize the advantages of LASEK and LASIK surgery, and better avoid the shortcomings of the two, which uses a rotating epithelial knife in the corneal epithelial layer "to do the active epithelial flap", the thickness of only more than 50 μm, rather than like the LASEK surgery with the alcohol immersion, in the While maximizing the "savings" in corneal thickness, the postoperative irritation is minimal, the chance of corneal haze is less than with PRK, and the incidence of myopic regression is low.
Not all myopic patients are suitable for
Ocular excimer laser surgery can be considered only if the following conditions are met: over 18 years of age, have a healthy state of mind, and have the desire to remove glasses; there is no active ophthalmic disease of the eye; myopia is relatively stable in the last two years, and the deepening of the myopia is not more than 50 degrees per year; if you wear contact lenses, the soft lenses should be removed for 2 weeks, and the hard lenses should be removed for 4 weeks, and the soft lenses should be removed for 4 weeks, and the hard lenses should be removed for 4 weeks. Rigid lenses should be removed for more than 4 weeks (can be replaced with frames in order to do the pre-surgical examination); after the doctor's examination, all the indicators of the eye meet the requirements of the operation; if it is the second operation, the interval between the LASIK should be 3 to 6 months, and the interval between the PRK should be 1 year; if there is hyperopia, myopia, and astigmatism after penetrating corneal transplantation, the interval should be more than 1 year as well; and the body is free of surgical restriction of the disease.
People with the following conditions are not suitable for excimer laser surgery: acute and active inflammation of the eye, dry eye, eyelid closure, glaucoma, cataracts, uveitis, retinal detachment, ischemic ophthalmopathy, herpes simplex and other viral ophthalmopathies, and the following systemic diseases, such as diabetes, collagen disease (lupus erythematosus, etc.), rheumatoid arthritis, gout, mental illness, medication users. AIDS, people with certain diseases that affect wound healing or people who are qualified for surgery but have concerns or high expectations, as well as pregnant and breastfeeding women.
Safety is the focus of public concern, the first choice is still to wear glasses
There are usually three ways to correct myopia: 1. lens correction: including frames, corneal contact lenses; 2. corneal refractive surgery: radial keratotomy (RK), excimer laser cutting (PRK), excimer laser in situ keratomileusis (LASIK), etc.; 3. intraocular refractive surgery : Clear lens extraction, IOL implantation in crystalline eyes, etc.
It should be noted that, from the safety, simplicity, economy, practicality and other factors, the ophthalmology community believes that for the majority of people, the current preferred method of correcting myopia is still to wear frame glasses. If patients are ready to choose excimer laser surgery, then the most concerned issue is the safety of the operation.
Objectively speaking, the safety of the current excimer laser surgery is relatively high, compared with the earliest use of diamond knife myopia radial keratotomy, its safety has undergone a qualitative leap, after more than 10 years of clinical practice has fully proved this point, it can be said that laser treatment of myopia surgery in our country so far has been relatively mature. However, the success rate of any surgery cannot be 100%, just like contact lenses are easily infected and jeopardize vision, while trauma caused by rupture of framed eyeglasses lenses is also one of the causes of blindness. The American Journal of Ophthalmology article pointed out that the failure rate of this type of eye surgery is 1/10, most refractive surgery experts in China hold a different opinion. Of course, good surgical equipment, skilled operation and rich experience of the surgeon, as well as the patient's good cooperation, is the basis for high safety of surgery.
Any surgery has its risks, and myopic laser surgery cannot completely avoid complications. The most common complication is overcorrection or undercorrection, these have to be observed after a certain period of time, discretionary second surgery; some people can have glare, that is, at night a point of light will be seen as a light ball, halo, which can be due to the postoperative corneal tissue between the reaction of a slight edema or the pupil at night is larger, the edge of its edge and the surgical rim is close to the relevant, with the gradual reduction of the postoperative time lapse; cone cornea in the potential of this or the cornea after the surgery thinness; eccentric cuts may occur because of poor target gaze or central islands due to aqueous swirling of the corneal surface; clouding of the cornea (Haze) and hormonal IOP from prolonged administration of anti-Haze medications may be present after PRK and LASEK; and complications associated with corneal flaps, such as subflap foreign bodies, flap dislodgement, and lysis, are associated with LASIK. increased astigmatism, and self-conscious eye dryness. The most serious is infection of the surgical corneal wound, which, although rare, is a direct cause of blindness, so a strict system of surgical sterilization and good patient hygiene are essential. You should also check your eyes regularly after surgery, paying special attention to changes in the macular area of the fundus and the peripheral retina, so that you can save for a rainy day.
Strict post-operative medication and review is an important part
Some of the patients had unsatisfactory results or complications after surgery because they did not strictly follow the doctor's instructions on medication and review. On the day of surgery, if you have eye symptoms, you can close your eyes and rest, do not remove the transparent eye mask, do not squeeze your eyes and rub your eyes. On the next day, the doctor will remove the transparent eye mask and check the visual acuity, cornea and refractive status, and then go for review 3 days, 7 days, 1 month, 3 months, 6 months and 1 year after the surgery. Especially in the early postoperative period, the doctor can adjust the medication in time according to the review results, which is also an important part to ensure the success of the surgery. Patients should also be instructed to avoid going to smoky and dusty places within one week after the surgery, eat less spicy and stimulating food, and do not wear make-up on the eyes to avoid water and fine particles into the eyes. Many people return to normal vision on the second day after surgery, but then the vision fluctuates in the following days, some people's vision is gradually return to normal, most of the two weeks is more stable, the final recovery period of 3 to 6 months. after LASIK surgery, you can take three days of oral antibiotics to prevent infection; also point to use antibiotic eye drops, hormone eye drops and promote the growth of corneal epithelium, lubrication and anti-drying of the eye drops, usually no more than one month. In one month should be less close fine eyesight (including looking at the computer, television). After surgery due to the change of refractive state, some people will feel difficult to see near in the early days, easy to fatigue, if the work and study can not be avoided, it should be more intervals, more blinking, more rest, generally with the passage of time the symptoms gradually disappear. Furthermore, it should be noted that do not swim within one month, avoid diving and intense confrontational sports, so as not to impact the eye, resulting in ocular trauma, corneal flap displacement or even loss. If you have symptoms of glare, you should wait for the symptoms to disappear before driving at night.
Health Economics of Eye Laser Surgery
The price of excimer laser surgery varies from procedure to procedure＼ hospital to hospital. For example, the LAISK procedure is priced at $6,000 to $8,000 in most hospitals, but some cost as little as $2,000 and some even as little as $800. What you need to be alert to is that there is a limit to reducing costs, and the reason why some hospitals are very cheap is because they use equipment and materials that have long been phased out in foreign countries, which are definitely outdated technology or have quality problems, and the surgical results cannot be the same, so be sure to choose a large hospital with guaranteed credibility and technology.
Out of the misunderstanding rational evaluation
In recent years, China's rapid development in the field of laser treatment of myopia is unprecedented. However, there are two extremes of public psychology in China:
The first is the deification of the effect of the surgery. The current laser surgery has not yet reached the point of perfection, especially in the correction of high numbers such as 1200 degrees or more, its predictability, safety and postoperative stability is obviously insufficient. Moreover, in the case of pathologic myopia, the surgery is required only to improve distance vision on the visual acuity chart, ignoring the fact that laser is only an optical correction and does not help the existing pathology of the fundus.
Another opposing viewpoint is the complete rejection of laser surgery for myopia, the so-called "treatment of the symptoms but not the root cause," while ignoring the fact that for low to moderate myopia, more than a decade of practice has proved that the effects of laser surgery are real, stable and reliable.
Additionally, some patients who had surgery 15 years ago do need to "go back to work" today, but not all of them do. "The reason for this is twofold: First, because the radial keratotomy (RK) of the past was less safe than PRK, LASIK, etc. Second, it is now known that not all patients have the same safety profile. The second is that it is now known that not all myopic patients can use RK surgery. The pathology of myopia varies, especially high myopia (over 600 degrees), which is categorized into simple and pathologic. Simple high myopia can be treated with surgery, while pathologic high myopia requires scleral reinforcement before surgery. Myopia over 1500 degrees should be treated with IOL implantation. And it is inappropriate to use the same type of surgery for all myopia in the past. In recent years, there have been great improvements in myopic laser surgery methods and equipment, especially the emergence of corneal wavefront aberration-guided excimer laser personalized cutting (ORK), which makes the shape of laser cutting more in line with the optical characteristics of the cornea, with better results and fewer complications. In addition, ophthalmologists have become significantly better equipped to handle the situation, so there should be fewer and fewer "reworks" of procedures performed in recent years.
All in all, the practice of these years has proved that the safety and effectiveness of myopic laser surgery has been greatly improved, so it is not desirable to hold a completely negative attitude, of course, this kind of surgery after all, has only been carried out for more than a decade, its long-term effect and safety is still under further study, so that the myopic laser surgery has been perfect, there is no risk is also unwise. Only out of the misunderstanding, calm and in-depth research, scientific and objective evaluation, is a rational attitude. In particular, it should be reminded that there are still some places in China where people flock to this technology for pure profit and abuse it, so it is especially important for patients to consider carefully before choosing the surgery, weigh the pros and cons, and choose a regular medical institution and experienced doctors.
Links
About excimer laser treatment of myopia
In 1983, Dr. Stephen of Columbia University in New York first tried the excimer laser in refractive surgery and began trials on animal corneas. In the early 1990s, the U.S. FDA began clinical trials of excimer laser corneal surface cutting (referred to as PRK), when most of the treatment range between low and moderate myopia. 1995, the U.S. FDA approved the PRK surgery for the treatment of low and moderate (600 degrees or less) myopia; in 1999, through the LASIK used for high myopia, hyperopia and astigmatism in the clinical treatment. China introduced excimer laser in 1992 to carry out PRK, followed by LASIK.
Compared with the earliest myopic radial keratotomy using a diamond knife, excimer laser surgery has the advantages of less damage, high precision, predictability, fewer complications, and a wide range of indications, etc. It can achieve the purpose of correcting myopia by cutting the corneal tissues of the central region to make it flat, in addition to correcting hyperopia and astigmatism. It can also correct hyperopia and astigmatism. In the case of hyperopia, the corneal tissue in the periphery is cut in a circular manner to make the central cornea steeper; if the cutting surface is oval, astigmatism can be corrected. Myopia (or hyperopia) and astigmatism can be corrected at the same time. Thinning of the central cornea can give the effect of wearing concave lenses, while thinning of the periphery can give the effect of wearing convex lenses. Of course, excimer laser surgery is only a way to correct myopia, only to correct the number of degrees "set" in the cornea, and can not change the pathological process of myopia to cure myopia.