The pros and cons of laser surgery to treat refractive errors
Source: China Optical Online Author: Yu Yongxin
With the continuous development of science and technology, related treatments and The methods and means of correcting refractive errors (refractive errors include myopia, hyperopia, and astigmatism) are changing with each passing day. There are surgical methods, wearing RGP, wearing OK lenses, wearing soft contact lenses, wearing glasses, etc. Because many refractive error treatment methods have a strong sense of commercialization with the participation of many businesses. Under the commercial hype, customers are lost in the overwhelming advertising. Nowadays, surgical methods are increasingly used by younger patients with refractive errors. In particular, some businesses only promote their advantages and downplay their disadvantages. A typical example is excimer laser surgery (PRK, LASIK, PTK). Exaggerated publicity for the treatment of refractive errors, and misled by false advertising, many patients believe that this technology is omnipotent and are completely unaware of its possible sequelae and dangers.
For example, a survey by the Ophthalmology Department of a hospital affiliated to a medical university in Shanghai showed that many patients choose laser surgery simply to get rid of their dependence on glasses; some patients consider laser surgery from a cosmetic perspective. Respected and authoritative medical experts believe that performing laser surgery on normal eyes just to get rid of glasses or contact lenses is not worth the gain.
LASIK laser treatment for refractive errors was proposed in the 1990s and is now the most commonly used method. Before the operation, fundus examination, intraocular pressure measurement, A-type ultrasound, corneal topography and refraction must be performed. Then, preoperative topical anesthesia is performed, and part of the cornea of ??the eye is incised, just below the incised corneal flap. The corneal stromal layer is laser cut, and finally the cut part of the corneal flap is reset. After the operation, antibiotics and some hormonal drops are required.
So, what are the advantages and disadvantages of laser surgery in treating myopia?
Advantages of laser treatment for myopia: The effect is ideal for customers with low and moderate refractive errors. The rebound rate of myopia is low. The surgery can temporarily eliminate the need to wear glasses for a period of time.
The current problems and disadvantages of laser treatment for myopia are also very obvious: because this surgery has been around for a long time, ophthalmologists are still unable to calculate and determine its long-term effects; some patients have a long period of time after surgery. Take eye drops within a certain period of time, otherwise your eyes will become dry and uncomfortable, and some may even take eye drops for a lifetime. In addition, the following complications are likely to occur during and after the operation:
1. Corneal flap deviation from the center, corneal flap misalignment, corneal flap wrinkles, corneal interlayer debris or blood residue;
2. The laser cutting is off-center, and the keratome cuts through the cornea;
3. Life-long glare and dazzling after surgery: myopia is more common at high altitudes, and there is blur when looking at things. Halo;
4. Under-correction or over-correction: If this happens, re-operation will be required, and the effect after the re-operation is not very satisfactory;
5. Vision rebound: especially for high myopia For many patients, their vision begins to decline a few years after surgery;
6. Best corrected visual acuity declines: after surgery, the vision cannot be achieved with glasses;
7. Dyslexia, dry eye, decreased corneal sensitivity, pain;
8. Irregular astigmatism: Almost all patients have varying degrees of irregular astigmatism after surgery.
9. Corneal infection, diffuse interlaminar keratitis, formation of central corneal island:
10. Peripheral corneal degeneration or scar formation, central corneal pigmentation.
Based on the above reasons, most doctors are unwilling to perform laser surgery on myopic people, regardless of profit. Regardless of the incidence rate of the above-mentioned sequelae, if any one of the many complications falls on a patient who undergoes this surgery, it will be a lifelong regret and misfortune. Because we only have one pair of eyes, light is a priceless treasure.
What’s even more dangerous is that according to strict medical regulations, a keratome can only be used on one eye. However, nowadays some hospitals or myopia treatment centers, in order to obtain high profits, reuse a keratome, as is often reported It is the same as saying that dialysis tubes in hospitals are reused. Therefore, before doing this surgery, do not listen to one-sided opinions from one party alone, but must carefully consider and weigh it repeatedly. On the other hand, this surgery is expensive, costing thousands of dollars. We hope that patients with refractive errors should carefully weigh the pros and cons and think twice before proceeding.
References: 1. Wang Kangsun's "New Ophthalmic Laser Technology" (People's Military Medical Press, March 2002)
Author's unit: Shenzhen Doctor Optical Co., Ltd. Kunming Division
Reference material: /bangda/read.php?wid=43
Laser treatment for myopia is currently a method favored by many people who want to "take off their glasses." However, before doing this surgery Before proceeding, be aware of the possible sequelae it may bring.
Currently, laser treatment methods mostly use excimer laser keratectomy (PRK) and excimer laser in situ keratectomy (LASIK). In the refractive system of the eye, the refractive power of the cornea accounts for 70% of the total refractive power. A slight change in the refractive power of the cornea can significantly affect the degree of myopia. PRK and LASIK correct myopia by cutting the central cornea to thin it and reduce its refractive power. PRK is mostly used to treat moderate to low myopia, but due to the destruction of the normal anatomical structure of the cornea, postoperative complications such as corneal subepithelial haze, glaucoma or high intraocular pressure, glare and regression may occur. LASIK can maintain the normal anatomical structure of the anterior corneal tissue, reduce subepithelial turbidity and refractive regression caused by the healing reaction of the postoperative corneal tissue. It has better prognosis, better postoperative recovery and stability, and is suitable for middle-aged and older adults. Treatment of high myopia and myopic astigmatism. However, LASIK may also cause complications, such as infection, under- or over-correction, corneal penetration, iatrogenic corneal astigmatism, secondary keratoconus, corneal flap irregularity, glare, etc. If these complications are discovered in time and handled properly, most of them will not leave any sequelae or affect the curative effect. However, some complications do hinder vision recovery, such as myopia that is overcorrected before surgery and becomes high myopia after surgery; or there is no astigmatism before surgery, but it becomes high astigmatism after surgery, etc. If the remaining cornea is too thin due to surgery, reoperation cannot be performed to remedy it. For another example, corneal penetration during the operation or severe keratoconus secondary to the operation may force the patient to undergo corneal transplant surgery, bringing new troubles to the patient.
Moreover, there are age requirements for eye laser surgery. If you are younger than 18 years old, it is not suitable for surgery, because the eyeballs of people under 18 years old are not fully developed and the refractive status is not yet stable, so the surgical effect is also unstable. If you undergo surgery blindly, your vision will most likely deteriorate after one or two years. Therefore, both surgeries require patients to be between 18 and 55 years old and have myopia that has been stable for more than 2 years. The best age for surgery is between 25 and 30 years old. Severe dry eye disease, exophthalmos and eyelid insufficiency, glaucoma, and monocular patients are absolute contraindications for surgery. Since glare may occur after surgery, drivers and other special professions need to carefully consider surgery. Even if good naked-eye vision is achieved through surgery, fundus and visual acuity should be checked regularly.
Investigation on Safety Issues in Laser Surgery for Myopia
About 10% of patients who undergo laser surgery for myopia need to “rework”. This data is basically consistent with the 10% failure rate published in the British Journal of Ophthalmology. In some hospitals with poor conditions, the success rate is even lower than 70%. So how safe is excimer laser surgery for myopia?
Surgery like magic
At 2 pm on May 19, the Refractive Specialist Department of the Eye Center of Beijing Tongren Hospital. As usual, the 30-square-meter waiting room was packed with patients. They are not ordinary eye disease patients, but a group of people with what is medically known as refractive abnormalities, myopia, hyperopia or astigmatism - the light entering the eye cannot focus on the retina after being refracted by the cornea and lens.
Here, excimer laser surgery will reshape the curvature of their cornea. Surgeons use invisible light with wavelengths in the ultraviolet spectrum, which can very precisely break the molecular bonds of corneal cells and vaporize the corneal tissue without causing any thermal damage to other tissues.
The operating room officially opened at 1 p.m. and ended at nearly 5 p.m. The reporter saw patients, groups of more than a dozen, filing in and out.
Although the operation requires jade-like finesse, the time is incredibly short. From eye anesthesia to completion, it only takes about 5 minutes. A nurse in the examination room said that there were 60 patients in total this afternoon. "It's like this almost every day. Sometimes there are 20-30 people."
On the wall of the waiting room, It’s full of “Instructions for Patients.” An article "Currently Widely Performed Excimer Laser Surgery" introduces that excimer laser keratomileusis (PRK), excimer laser subepithelial keratomileusis (LASEK) and excimer laser in situ keratomileusis (LASIK) ) Among the three surgical procedures, LASIK has the widest range of applications and has been clinically proven to be the safest and most effective so far.
Liu Xiaoming, a myopic patient from Hebei, was in the last batch of the day. Two days ago, she rushed to Beijing Tongren Hospital from her hometown for a check-up. After ruling out various surgical contraindications, the doctor chose LASIK for her. This surgery cost her more than half a year's salary: 4,368 yuan per eye, plus The total cost for pre- and post-operative examinations and medications is around 9,500 yuan. And if you do it in your hometown, you can save at least 3,000 yuan.
"I don't dare to do it in a small hospital. Recently, isn't it said that many people who have had this operation need to go back to work?" she said after just walking out of the operating room.
The next day, she found that she no longer needed to wear glasses when watching TV. She was overjoyed on the phone, "It's like magic. The doctor said my vision can be restored to 1.2." But then, she Started to worry about the rumors.
The wave of rework is worrying
The news of the "wave of rework" first came from Shanghai. Fifteen years ago, radial keratotomy (RK) for myopia was all the rage. But after a few years, many patients who underwent the surgery began to experience serious postoperative complications that led to vision regression. The media said that in the ophthalmology departments of some tertiary hospitals in Shanghai, the number of redo surgeries in a year exceeds 600, and is increasing at a rate of 20% every year.
In Beijing, the situation is also not optimistic. It was recently reported that in some hospitals, "more than 1,000 people come for myopia laser surgery every month, and nearly a hundred patients undergo 'rework' surgery at the same time," accounting for about 10% of the total number of patients.
The questions raised by this are obvious: Although the RK technology that emerged 15 years ago has long been eliminated due to its own shortcomings and replaced by safer PRK, LASEK or LASIK, 15 years later these Will technology follow in RK’s footsteps?
Similar warnings were issued earlier internationally. On December 15 last year, the British Institute for Clinical Excellence (NICE) published a report titled "Guidelines on LASIK Surgery for the Treatment of Refractive Errors" stating that for widespread use, there is currently too little evidence to demonstrate this. Due to the long-term safety of the surgical method, LASIK should not be used as a routine clinical practice and should not be included in the National Health Service (NHS) without further research and approval.
In the report, NICE also compiled four clinical data and found that the incidence of postoperative corneal flap problems such as corneal flap dissolution, corneal flap too thin, and corneal flap position deviation is about 4%. The incidence of corneal burning sensation is 5%, and the incidence of corneal tissue hyperplasia is about 2%.
The Sunday Times reported on the NICE report before it was released. It also quoted data from a paper published in Ophthalmology by Dr. Peter S. Hersh of the New Jersey Medical College in the United States. , claiming that the secondary operation rate of this type of surgery is 1/10, not 1/1000 as stated in many advertisements. This report caused shock around the world and was called the "UK's Suspension of Excimer Laser Surgery Incident" .
Immediately, the British Broadcasting Corporation also made a follow-up report. Bruce, chairman of NICE's interventional care advisory committee. Professor Campbell said in an interview that because vision correction can be solved safely by wearing glasses or contact lenses, any treatment that carries risks to the eyes such as LASIK requires special attention.
Professor Campbell also warned that a small number of people had worse vision after LASIK surgery, and eye experts were concerned about possible long-term side effects of the surgery.
However, the BBC's report appeared to be more objective. It also interviewed a number of clinicians who generally expressed disappointment with the NICE report.
The American eye surgery community also refuted the NICE report. In 2004, there were 1.2 million eye laser surgeries in the United States, while there were only 100,000 in the UK. USAeyes sarcastically stated on its website that if the incidence of postoperative complications was really that high, the United States should have been the first to discover it.
New conclusion?
Domestic media reports have once again raised public doubts about excimer laser surgery. Since May 20, reporters have called NICE, the Vision Center of Queen Victoria Hospital in the UK, and Dr. Hersh, the author of the paper in the magazine "Ophthalmology".
On May 26, Sheraz, Director of the Vision Center of Queen Victoria Hospital in the UK. Dr. Sheraz Daya responded to this newspaper’s questions via email.
Reporter: What is the current clinical application of LASIK in the UK? Will the public accept this surgery?
Daya: L ASIK is not as popular in the UK as in other countries. There are several reasons. First, the British are naturally conservative and overly concerned about safety. Second, LASIK has not yet entered the NHS (equivalent to Welfare and medical care - Editor's note), the British are not used to spending their own money on medical care.
Reporter: Is the long-term safety of this surgery guaranteed?
Daya: As long as the medical procedure is correct and the patient has no contraindications, there will be no problem.
Reporter: But NICE has issued a warning.
Daya: NICE’s report is very poor and uses very old data. As no new data were included, the inference that there was little clinical practice experience in the UK is incorrect. The NICE report did not fully take into account the UK's level and practical experience in this area. As far as I know, the relevant issues are being re-evaluated, and we believe the new conclusion should be different.
Reporter: "Ophthalmology" once published an article saying that 1/10 patients need secondary surgery. In your treatment center, what is this number?
Daya: Second treatment or correction is not considered a failure. This was a misunderstanding in the past. In the past few years, the secondary surgical treatment rate in our own center has been 2%. After the introduction of femtosecond laser lamellar scalpel technology, it has now further dropped to 0.5%. I personally think it would be a shame if there was still a 10% (failure rate) now, in 2005, and I don't want this to happen in some good medical centers.
Reporter: What new views do you have on this technology now?
Daya: This technology is very good and represents the future direction. It is really unforgettable that we can use this technology to change the lives of so many people!
Dr. Hersh also denied people's misunderstanding of 1/10 in his article, "The 10% I said is the second surgery rate, which is often used to achieve better visual effects. Now LASIK occurs Complications are less than 1%.
NICE is extremely cautious. In multiple contacts, public relations manager Woodward said that Professor Campbell attaches great importance to it and is studying your interview questions and will discuss them later. Give a reply. ”
The problem still exists
After the NICE report was released, the Chinese ophthalmology community also organized a discussion two months ago. Zhao Jialiang, chairman of the Ophthalmology Branch of the Chinese Medical Association, said, Their main opinions were published in the fifth issue of this year's "Popular Medicine" magazine. "There are currently no new additions."
LASIK is currently recognized as the safest and most effective refractive surgery in the world. , they have no objection, but "the success of the operation is closely related to factors such as surgical design, doctor's technical level, and the quality of laser equipment." my country introduced PRK in 1993 and subsequently carried out LA SIK. The overall level is the same as the world's advanced. "While some low-level medical institutions with poor conditions are also carrying out excimer laser surgery and competing at low prices, this phenomenon is worrying. ”
Professor Zhao Jialiang estimates that more than 1 million patients have undergone this surgery in China in the past two years. He said that in fact, any surgery has risks, and the same goes for excimer laser surgery, and it is just a The icing on the cake is not a must-have surgery, and patients must be careful when choosing.
The preoperative informed consent form of the Refractive Specialty Department of Tongren Hospital’s Eye Center lists 21 possible serious consequences. : In case of severe infection, allogeneic corneal replacement is required, which may seriously affect vision; there is the possibility of over-correction, under-correction and refractive regression; sometimes pathological myopia cannot be determined before surgery, and the degree of myopia developed after surgery may be higher than the original degree. There is a higher possibility; patients with any degree of refraction have the possibility of secondary surgery...
“Although the possibility of surgical complications is very low, we must clearly inform everyone of these situations. For one patient, excimer laser surgery is also a minimally invasive surgery and cannot achieve the expected results in 100% of patients. " said Dr. Zhou Yuehua, deputy director of this specialty.
However, the doctor's own technical mastery, the reliability of the equipment and the standardized execution of medical procedures can also make such a delicate operation as LASIK perfect. According to Zhou Yuehua According to the data provided, more than 95% of Tongren Hospital’s primary surgeries have achieved the desired results. From 1993 to the present, there have been no serious complications.
“Second surgeries do not mean failure, because every operation has achieved the desired results. The conditions of the patients themselves are different, and some surgeries are designed to be completed in two steps, such as older patients with high myopia. "He said.
But there are obviously loopholes in safety in some areas. Within four days from May 16th to 19th, Tongren Hospital admitted three patients with severe LASIK complications. In In their medical records, Zhou Yuehua wrote down the diagnoses of "broken corneal flap" and "dissolved corneal flap", but he was unwilling to explain the reason too much, "Because I am in the position of a colleague, it is inconvenient to comment on other hospitals. "
Tongren Hospital encounters hundreds of failed surgeries like this every year. "Popular Medicine" disclosed, "The success rate of some hospitals is below 70%, and the situation is not optimistic. "A secret that is no longer a secret in the industry is that some hospitals directly purchase second-hand equipment from abroad in order to reduce costs
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When you are faced with overwhelming advertisements from hospitals of all sizes, each hospital says how new and advanced their equipment is, and how brilliant their doctors are. It really makes you confused when making a choice. At a loss.
It is recommended to be rational and calm when making your consumption choices, and be wary of the loudest fishmongers in the market, who are often stinky! Medical advertisements are often watery and exaggerated! p>1.
Pay attention to misunderstandings when choosing equipment:
Common misunderstandings about excimer laser treatment of myopia:
A. Which generation of laser is the best?
Answer: There is no unified "generation" in the world to mark the advancement of lasers! Never blindly believe in advertising and media propaganda! Because there are one or twenty manufacturers in the world that produce excimer lasers, each manufacturer has its own update number, and only the generations of the same manufacturer can be compared.
B. Is the smaller the spot of the excimer laser, the better?
Answer: No! If the light spot is too small and the emission frequency is certain, the operation time will be prolonged and the operation will be affected.
C. Is the newer the laser equipment, the better?
Answer: No, technological updates, especially medical updates, often take 5 to 10 years to verify. New machines require doctors to get used to them, just like a new car needs a running-in period.
D. How to know the quality of the equipment?
Answer: The data is the most convincing!
Major excimer laser equipment in the world:
Wavelength energy scanning time
Germany InBev Le 193nm 120-180 Gauss 6 seconds patented
German Alice 193 134 flying point 22 seconds
American Nuctech 193 140 flying point 25
American Eagle Vision 193 130 Flying point 18
Japan Nidec 193 130-150 Rotation 30
(Others omitted)
As can be seen from the above table, various laser data Basically the same, but the surgery time is different! Because the time is shorter, the cornea is exposed for less time, reducing dryness, the surgical effect is good, and the patient cooperates well on the operating table.
E. Follow the advertisement!
2. It is better to choose a doctor than to choose a hospital: As the saying goes: "The mountain is not high, if there is a god, it will be spiritual; if the water is not deep, if there is a dragon, it will be famous". Because sometimes "the temple is small and the god is big", but sometimes "the temple is big and the god is small", it is better to seek the "true god" than to worship the "big temple".
In addition, the qualifications of the surgeon not only depend on the degree, but also the actual clinical experience and the doctor's status in the field of myopia. How many cases of myopia laser surgery experience do you have? How many years of laser surgery have you had for myopia? Does the surgeon have enough experience? Is there a record of failure? What are the results for people who have had myopia surgery?
You can have an interview with the surgeon directly, or you can learn about it from the side.
3. Is the surgery covered by insurance?
In addition, the qualifications of the surgeon depend not only on the degree, but also on the actual clinical experience and the doctor’s status in the field of myopia. The true saying goes: "No matter how high the mountain is, there will be spirit if there is a god; no matter how deep the water is, if there is a dragon, then there will be a name." It is better to pray for "Buddha" than for "small gods". It is better to pray for "true God" than to pray for "big temple", because sometimes "temple" Small "gods" are big, sometimes "temples" are big and "gods" are small. Rather than worshiping a big temple, it is better to seek the true god.
★Original compilation by Komatsu Blog. Please indicate when reprinting★
The principle of laser myopia surgery is to use excimer laser, under computer control, to repair the corneal tissue on the surface of the black eyeball. Make it smooth, regular, and curved just enough for the light to focus on the macula of the fundus. If it is not smooth and regular enough, it will manifest as astigmatism. If the curvature is not in place, myopia correction will be insufficient or excessive after surgery. Whether the surgical efficacy is satisfactory or not is also affected by: 1. How well the equipment and engineers debug it. 2. The level of physician skills. 3. The influence of three important factors: patient cooperation and biological response.
There are currently two types of laser myopia surgery. One is called laser keratectomy (PRK), where a laser repairs the cornea from its surface. It is only suitable for myopia below 6.00D. PRK for myopia that is too high may easily cause corneal scarring and opacity.
Another kind of surgery is called Lasik. It uses a special knife to split the corneal layers to make a corneal flap, and perform laser repair in the corneal stroma. It is suitable for both high myopia and low myopia. The surgery It is more difficult and prone to corneal flap complications. My two daughters and I both had laser myopia surgery, and the results were good. But when I asked them how they felt, my sister said she "doesn't regret it." But my sister said: "Why don't you regret it? I will never do it again until I die." This shows that laser myopia surgery has both advantages and disadvantages!
Benefits: 1. It is currently the safest and most reliable method to correct myopia. Whether it is domestic and foreign reports or our own experiments, for patients with myopia of 6.00D or less, the long-term postoperative Stable naked eye vision, 92≥0.5, 70≥1.0. For highly myopic eyes above 6.00D, the higher the degree of myopia, the worse the long-term effect after surgery.
2. Compared with the charges for equipment and technology in the same advanced countries such as the United States, Germany, and Japan, domestic surgery charges are very low, only -1/6 of those in the above-mentioned countries.
3. Domestic doctors have rich clinical experience. Preliminary estimates indicate that the number of surgical cases has exceeded 300,000. Because of its high technology and low price, it has attracted many foreigners to come to China for surgery.
4. Fast. Laser irradiation only takes tens of seconds and does not require hospitalization.
Disadvantages: 1. The efficacy of surgery is not perfect. There are always complications in a small number of surgical patients. Some patients even have serious complications such as infection and eyeball perforation, resulting in decreased corrected vision or even blindness. Since laser surgery is It is performed on the healthy eye. The vision of this eye can be completely restored after wearing corrective glasses. If the vision is reduced due to surgery, the gain outweighs the loss. From this point of view, surgical patients are somewhat risky. When deciding to undergo surgery, both the doctor and the patient should think twice.
2. The current practice of laser myopia surgery in our country seems to be somewhat indiscriminate. A few units use commercial operations, the advertisements exaggerate, and they do not work hard on the technical level, which increases the possibility of complications.
3. Excimer laser equipment and technology are still developing, and a few units cannot keep up with its development, causing patients to suffer undue losses.