Question 1: What is the principle of excimer laser in treating myopia?
Answer:
Myopia is caused by the long anterior and posterior diameter of eyeball, the convex front surface of ocular membrane, and the external light can't converge to the fundus accurately. Excimer laser myopia correction (LASIK/PRK) is an excimer laser controlled by computer. According to the degree of myopia and whether there is astigmatism, the corneal stroma layer is etched in the pupil area, so that the anterior surface of cornea is slightly flattened. So that external light can be accurately converged and imaged on the fundus retina, and the purpose of correcting myopia is achieved.
Question 2: Is excimer laser surgery the best way to treat myopia?
Answer:
Generally speaking, excimer laser surgery is safe and effective. With the progress of science and technology and the accumulation of experience, the success rate of this operation will be further improved. It is an important way and mainstream surgery to correct ametropia at present. Numerous treatment methods can be divided into two categories, namely surgical treatment and non-surgical treatment. Non-surgical therapy has various optical correction devices, such as common frame glasses and various contact lenses; Various therapeutic instruments, functional training and physical therapy; There are three kinds of medication. There are four surgical treatments: corneal surgery, lens surgery, scleral surgery and laser treatment of presbyopia. The excimer laser surgery we are talking about belongs to corneal surgery, which can be divided into excimer laser keratectomy (PRK) with the best therapeutic effect for low degree and excimer laser in situ keratomileusis (LASIK) with the best therapeutic effect for high degree. Whether wearing glasses or contact lenses or using excimer laser surgery is an option for myopia patients to correct their vision.
Question 3: What is the difference between excimer laser correction surgery and other correction methods?
Answer:
Frame glasses are the most common refractive correction tools, suitable for myopia, hyperopia, astigmatism and other refractive errors, and can be worn by patients of all ages. Generally speaking, frame glasses can only correct vision, and have limited therapeutic and preventive effects on ametropia, especially for some high myopia, hyperopia and high astigmatism. Some special industries, such as drivers and etiquette, have some restrictions on people who wear glasses, which makes life inconvenient.
Compared with frame glasses, contact lenses have the advantages of wide vision, vivid vision, comfortable wearing, good mobility, beautiful appearance and safe use. Due to the limited oxygen permeability of general soft mirror materials, it is not suitable for wearing for a long time. There are also hard breathable contact lenses with excellent breathability, which are healthier for corneal tissue and suitable for patients of all ages, especially for ametropia patients who need to wear contact lenses for a long time.
There is also an Ortho-K CL, commonly known as OKCL, which can reduce part of myopia in a short time and quickly improve the naked eye vision of moderate and low myopia. However, orthokeratology mirror belongs to medical supplies and must be fitted under the supervision and guidance of ophthalmologists or optometrists. To maintain good control effect, you need to wear glasses for a long time.
These non-surgical methods avoid surgical risks and postoperative complications, and the correction effect is obvious and accurate, and can be corrected continuously with their own changes. However, the nursing work such as cleaning, maintenance, disinfection and regular inspection in the process of use is complicated, especially for children, which should be assisted, guided and supervised by adults to ensure safety. All kinds of physical therapy and drug therapy methods are safe and have certain effects on prevention, but the treatment cycle is long and the final effect is difficult to determine.
Excimer laser is widely used and popular in corneal surgery to treat ametropia. As mentioned in the previous question, excimer laser keratectomy (PRK) is like making the cornea into a concave lens or a convex lens to correct myopia or hyperopia. The operation method is simple, the safety is high, and the effect of medium and low degree (below 600 degrees) is better. However, there are some problems such as postoperative eye pain, degree rebound and corneal opacity. Excimer laser in situ keratomileusis (LASIK) is suitable for patients with moderate or ultra-high myopia (600 ~ 1500 degrees). The operation is predictable and accurate, with mild postoperative pain and quick recovery. However, the surgical technique is complex, and there are some problems such as insufficient or excessive correction, corneal astigmatism and degree rebound.
In addition, there are shallow corneal lens transplantation, interlayer corneal transplantation, interlayer artificial cornea, corneal stroma implantation, lamellar corneal transplantation and other surgical methods. These operations have their own characteristics for different refractive diseases, but most of them have certain limitations or immature techniques. The clinical application effect and value need further observation, so they have not been widely used and popularized. Lens surgery and scleral surgery are aimed at people with high myopia. Although they have good predictability and high efficiency, they have serious obvious side effects and complicated operations, so they must be strictly checked and reasonably selected.
This surgical method has clear goal, obvious effect and short treatment cycle. Successful operation can make patients return to normal life without troublesome nursing. However, surgery is an irreversible "trauma" to the eyes. In addition to the risks in surgery, there may be postoperative complications. In addition, the application history of some operations is still very short, only ten years from invention to now. At present, it is impossible to accumulate complete data of postoperative eye conditions from young to old patients, and its long-term effect and changes cannot be estimated. Surgery is irreversible, so you should be very careful when choosing it.
Question 4: Can everyone receive this kind of surgical treatment? Who is suitable for treatment?
Answer:
Whether it is suitable for excimer laser surgery depends on your psychological needs and the state of your eyes. Generally speaking, if the refraction is stable for two years, the corrected vision is good, and there are no other eye diseases, you may be suitable for laser corneal refractive surgery. Of course, the doctor will also do a series of strict preoperative examinations on your eyes. Preoperative routine examination is mainly to inquire about the medical history, understand the changes of vision and treatment methods in recent years, and whether there is a family history of cornea and corneal malnutrition related to heredity. And finally decide whether you can do it.
In some cases, excimer laser surgery is not suitable for myopia, such as eye abnormalities, systemic immune system diseases, pregnant women and so on. Only those with age of 18-50 years old, myopia of 200-3000 degrees, hyperopia of 100- 1000 degrees, astigmatism below 400 degrees, stable refractive index for more than 2 years, basically healthy physical condition and no other eye diseases.
At the same time, you should not expect too much from the psychological effect of the operation. In daily life, the vision of 0.5~0.9 can be removed without glasses, which is the standard for basic lens removal after operation. The postoperative visual acuity of most patients is around 1.0, which meets the general requirements of joining the army, driving and entering higher schools, and some patients reach 1.5 or even 2.0. But the degree of postoperative recovery varies from person to person. You should know the possible risks and complications of the operation so as to have a realistic expectation of the operation result. Question 5: Is the operation unsafe? What is the success rate now?
A: The laser used in the operation is a cold laser with the wavelength of 193 nm, and its penetration ability is weak. Moreover, the operation is an external eye operation, which will not hurt the internal eye and will not break the eye and cause blindness. Its energy is concentrated, and it will not produce a lot of heat to harm the surrounding cells. The key to its safety lies in strict preoperative examination and evaluation, and all contraindications (such as keratoconus, dry eye, glaucoma and other serious autoimmune diseases) are excluded. Practice has proved that PRK and LASIK are safe, effective and stable surgical correction methods as long as the indications are strictly mastered.
Question 6: To what extent can vision be restored after operation? Will it return to the original myopia degree in a few years? Can it be treated again?
Answer:
Binocular surgery only takes about ten minutes, and laser treatment can be completed in even tens of seconds. Postoperative naked vision generally reaches the best corrected vision before operation. Total correction of high myopia may be better, but the results will be individual differences.
The degree of myopia and astigmatism after surgery generally does not change. The original myopia is in an unstable state of continuous development, and new myopia will appear after surgery, which is known as "retreat". Therefore, the patient's surgery is a prerequisite, and the diopter is required to be stable for more than 2 years, so it is unlikely to retreat after 3-6 months, and even if it retreats, it is impossible to retreat to the original degree.
Question 7: What are the general discomforts after operation? What should I pay attention to?
Answer:
After LASIK, a few patients with extremely high degree may have glare at night or in the dark, which may be unavoidable for a long time. This phenomenon is that the higher the degree, the greater the possibility. However, patients who have undergone PRK surgery or whose degree is not too high are basically the same as those with normal vision.
Postoperative patients should pay attention to not doing close work as much as possible, such as watching computer and TV for a long time to avoid excessive use of eyes. Be sure to strictly follow the doctor's advice and follow some detailed rules. For example, you need to wrap your eyes with a transparent plastic eye patch on the day after surgery, and you must come to the hospital for a follow-up visit the next day. Be careful not to blink hard and let the sewage flow into your eyes. Although you can watch TV, read books and newspapers on the second day after surgery, it will not affect your vision recovery, but it is recommended that the time should not be too long, because there is an adaptation period in the early stage, which will easily lead to eye fatigue.
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