How does laser surgery for myopia work? What is the principle of laser myopia surgery

1. The principle of optical transmission.

Before the operation, the doctor will input the patient's basic information and surgical data into the computer (including the depth of laser focus, that is, the distance from the bottom of the coxone lens to the laser focus point; the diameter of the corneal flap, the size and width of the pedicle; the energy of laser cutting, etc.). During the procedure, the surgeon operates a femtosecond laser machine and uses a conicon lens to fix the cornea, thus maintaining the precise distance between the laser head and the laser focus point in the corneal tissue.

The depth of laser focus, that is, the distance from the bottom of the conical lens to the laser focus point, is transmitted by a femtosecond laser machine in a pattern set by the doctor to perform various targeted cuts on the cornea. Briefly, what impresses us most about the principle of light transmission of femtosecond lasers is the precise orientation and precise positioning of light transmission.

2. The principle of light blasting.

The laser pulse is focused into the corneal tissue, producing a photoblast; Each pulse of light bursts to produce a microion, and each microion, evaporates about 1 micron of corneal tissue; Evaporation of the corneal tissue produces expanded blisters and CO2 bubbles, which are absorbed by the corneal tissue, and the corneal tissue is thus separated.

The computer-controlled optical transmission system generates thousands of laser pulses, and thousands of laser pulses are focused at the same depth according to the dense fence wall pattern of equal width and equal spacing, producing a light blast, forming a layer of bubbles of tiny diameter in the corneal tissue, separating the corneal tissue and forming the corresponding separation surface, that is, the cutting surface of the femtosecond laser.

The principle of laser surgery is basically to use excimer laser or femtosecond laser or a combination of the two to cut the cornea.

The principle of myopia eye surgery is to change the refractive state of the eye, and the normal human eye should be able to focus on the retina when looking at light five meters away, but after myopia, it can only focus in front of the retina. Therefore, patients with myopia generally need to wear a pair of myopia glasses, which are essentially concave lenses, which change the curvature of the cornea so that the image can be refocused on the retina.

Myopia is mainly due to the fact that the anterior and posterior diameter of the eyeball is too long or the surface of the eyeball is too convex, so that the external light cannot be accurately focused on the retina, so myopia eye surgery is to use the excimer laser to refractive cutting the stromal layer under the corneal flap, so as to reduce the corneal curvature in the pupil area, so that the external light can accurately focus and image on the retina, and finally achieve the purpose of correcting myopia.

Myopia is caused by the elongation of the eye axis, and when light enters the eye, the image falls in front of the retina, so the vision is blurred. The basic principle of laser myopia surgery is to use a laser to remove a part of corneal tissue, adjust the corneal refraction, and let the image fall accurately on the retina again. Laser myopia surgery includes full femtosecond, half femtosecond, and full laser, and patients should go through strict preoperative examinations and choose a suitable surgical method for themselves according to the doctor's advice to correct myopia.

Excimer laser is a 193 nanometer cold laser produced by ARF gas decomposition and fission, which has a certain penetrating power to the human cornea, but will not produce thermal damage.

Excimer laser is an invisible ultraviolet beam with a wavelength of only 193 nanometers invisible to the human eye, which is characterized by large photon energy, extremely short wavelength, extremely weak penetration of tissues, will not penetrate into the eye, only absorbed by the surface of the tissue, no damage or minimal damage to the surrounding tissues, excimer laser corneal refractive ** technology (LASIK technology), is the use of a special extremely precise miniature corneal lamellar cutting system (referred to as keratome) to make the corneal surface tissue into a pedicled corneal flap, after flipping the corneal flap, Under computer control, the excimer laser is used to accurately vaporize part of the tissue to be removed from the corneal stromal layer under the valve, and then rinse and reset the corneal flap under the valve, so as to change the shape of the anterior surface of the cornea, adjust the refractive power of the cornea, so that the external light can accurately converge into an image in the fundus, so as to achieve the purpose of correcting myopia.

Myopia is caused by the anterior diameter of the eyeball being too long or the lens being too convex, and the external light cannot accurately converge in the fundus. Excimer laser is an invisible ultraviolet beam with a wavelength of only 193 nanometers invisible to the human eye, which is characterized by large photon energy, extremely short wavelength, extremely weak penetration of tissues, will not penetrate into the eye, only absorbed by the surface of the tissue, no damage or minimal damage to the surrounding tissues, excimer laser corneal refractive ** technology (LASIK technology), is the use of a special extremely precise miniature corneal lamellar cutting system (referred to as keratome) to make the corneal surface tissue into a pedicled corneal flap, after flipping the corneal flap, Under computer control, the excimer laser is used to accurately vaporize part of the tissue to be removed from the corneal stromal layer under the valve, and then rinse and reset the corneal flap under the valve, so as to change the shape of the anterior surface of the cornea, adjust the refractive power of the cornea, so that the external light can accurately converge into an image in the fundus, so as to achieve the purpose of correcting myopia.

1. Excimer laser keratomectomy (PRK).

Excimer laser surgery uses a 193nm wavelength ultraviolet laser to accurately cut the optical area of the cornea and reshape the curvature of the corneal surface. For **myopia, the range of correcting myopia is best below 600. The disadvantage is that the surgery destroys the Descemet's layer of the cornea, which is easy to cause corneal fog opacity, vision regression and steroid-induced intraocular hypertension, and a small number of patients have vision regression for a period of time after surgery.

2. Excimer laser corneal in-situ in-situ in-situ inlay (LASIK).

The principle of this surgery is the same as that of PRK, but on the basis of not destroying the cornea and the Descemet's layer, it combines high-precision cutting and in-situ grinding in the corneal stromal layer with an excimer laser, which greatly improves the performance, stability and safety of the operation. This surgery has a wide range of corrections and can correct any myopia below 3000 degrees (if the preoperative comprehensive examination and all indicators are met). **After that, there is almost no eye discomfort, no need to cover your eyes, and you can go to work, school and participate in physical examination the next day.

3. Excimer laser keratomileus inlay under the epithelial flap (LASEK).

This method is used for special cases with thin cornea and high myopia. **LASIK surgery is the first choice for myopia. There is a difference between true and false myopia.

According to medical principles and clinical experience, any instrument and other non-surgical methods can only help to prevent and prevent pseudomyopia, and only surgical methods can be used for true myopia. Although there are many surgical methods, the commonly used and preferred is the LASIK laser myopia method, which is accepted by 90% of patients who want to be myopic in the United States. Its characteristics are:

It is convenient, bitter and direct, and it only takes more than ten seconds, and you can go to work, school, and participate in physical examination the next day, and it is a lifelong effect.

4. Intraocular refractive surgery (ICL).

This procedure is suitable for the elderly and those with ultra-high myopia**, and the original refraction is changed by removing the clear or opaque lens and implanting different anterior or posterior chamber intraocular lenses. The advantages are that the refractive effect is stable, there is no regression, and the postoperative recovery is fast.

The principle of ophthalmic laser surgery is to use a laser to change the corneal thickness and radius of curvature.

1. What is the principle of laser surgery for myopia?

1. The principle of myopia laser surgery is to cut the corneal stromal layer by means of excimer laser, femtosecond laser and other means to change the radius of corneal curvature and corneal thickness. This changes the refractive state of the eye, which corrects refractive errors, including myopia and astigmatism.

2. At present, this kind of surgery has been widely used in clinical practice, so the surgical technology is also very mature. If you have myopia in your eyes, you can consider this method. The most commonly used methods are mainly excimer laser surgery and femtosecond laser surgery.

Excimer laser surgery is the earliest surgical method for myopia. Compared to excimer laser surgery, femtosecond laser surgery has higher precision, so the quality of vision after surgery will be better.

2. The method of laser surgery for myopia by hand.

1. Myopia laser surgery uses lasers of different wavelengths such as excimer laser and femtosecond laser to cut corneal tissue on the cornea according to the different parameters of each patient to make a concave lens shape. In this way, when outside light enters the eye, it can be accurately imaged on the retina through the concave lenticular corneal tissue and refractive tissue inside the eye, and the person suffering from hail can see things in the distance.

2. The main cause of myopia in laser surgery is corneal decompensation caused by corneal tissue cutting, such as postoperative eye pain, dry eye, decreased night vision, night glare, refractive regression for a long time, etc.

In summary, patients should have an understanding of the surgery before surgery, and can choose the appropriate surgical method according to their own situation.

Myopia laser surgery is to cut the stromal layer of the cornea through excimer laser, femtosecond laser and other means, which can change the radius of curvature of the cornea and the thickness of the cornea, and in this way, the refractive shape and bending of the eye can be changed, so as to correct the refractive error, including myopia and astigmatism.

1. Pay attention to the time you spend with your eyes.

Children's eye development is not perfect, the ability to work is low, every time you read or write for an hour, you should let the child go to outdoor activities, do games, look into the distance, or observe the flowers and trees, so that the tense eye muscles are relaxed, eliminate fatigue. In addition, it is necessary to make the child's life regular, have enough sleep, and let the eyes get enough rest.

2. Pay attention to the light of your eyes.

Do not allow your child to read or write in dark light or sunlight. If a 25-watt light bulb is used indoors at night, the distance between the book and the bulb should be within 1 meter. If you use a 60-watt bulb on a stool, the distance between the book and the bulb should be 1 2 meters.

Cloudy days, dusk, weak light in the moonlight, and strong light in the sun are not suitable for reading and writing. When watching TV, it is necessary to maintain a suitable distance, which should generally be 5 7 times the diagonal length of the phosphor screen. The time to watch TV should not exceed 2 hours at a time.

Clever sedan chair. 3. Pay attention to eye exercise.

Physical exercise can enhance blood circulation and metabolism, supply more nutrients to the eyes, and enhance the resistance of the eyes, which is an indirect stool hunger exercise for the eyes. The direct exercise is eye exercises, which is based on the massage, massage, acupuncture and moxibustion acupuncture points of Chinese medicine, combined with the medical sports of jujube kuanhui, which is a scientific jujube kuanhui method to protect eyesight. Parents should learn the basic knowledge of eye exercises, give specific guidance and often urge their children to do eye exercises, and persevere.

4. Pay attention to eye nutrition.

In order to protect children's eyes, children can eat more carrots, animal liver, lean meat, to supplement vitamin A, or regularly supplement the comprehensive nutrition of the eyes with Leyan vision nutrients, and at the same time, it is also necessary to appropriately consume millet, tofu, animal liver and other supplements of vitamin B2, so as to avoid night blindness, corneal malacia, red eyes, dry itching and other symptoms. Eating too much sugar will harm your child's eyesight, so your child's sugar intake should be controlled.

5. Pay attention to regular inspections.

Regular check-ups are due to the fact that children's eye structure, binocular visual function, and intelligence are still in the process of continuous development after birth, and the content of the examination is different at different ages. The usual age of ophthalmologic examination is generally 2-7 days after birth, 42 days after birth, 3 months, 6 months, and 1 year of age, and then once a year. In this way, the problem can be detected early and corrected early, instead of waiting until the vision has deteriorated and there is a vision problem before going for a check-up.

The principle of laser myopia eye surgery is mainly through laser surgery, the cornea is reshaped, the corneal stromal layer can be effectively cut through the laser, and the residual cornea after cutting forms the optical principle of concave lens, when using the principle of corneal concave lens, it will cause the development of corneal incident rays, and the focus of corneal incident rays will be shifted backward, so that the focus of myopia can be improved, in addition, the retinal focus can fall on the retina, so it will improve the naked eye vision, and** Myopia, improve refractive error and other clinical manifestations. The principle of laser surgery for myopia is to cut the stromal layer of the cornea by means of excimer laser, femtosecond laser and other means, so that the radius of curvature of the cornea and the thickness of the cornea can be changed, and the refractive state of the eye can be changed in this way, so as to correct refractive errors, including myopia and astigmatism.

The principle of myopia surgery, that is, excimer laser surgery, is that because myopia is caused by the anterior and posterior axis of the eye being too long or the refractive index of the eyeball is too high, the focus of imaging falls in front of the retina, and the vision of distant things is blurred. By changing the refractive index of the eyeball so that the focus falls on the retina, myopia is corrected.

The process of myopia surgery: the cornea is first cut, circumcised 330 degrees, and the corneal flap is created, and then the corneal flap is lifted to expose the corneal matrix underneath. At this time, a laser is used to align the corneal stroma to evaporate a part of the stromal tissue, and the stroma becomes thinner, and the curvature of the cornea changes.

How much substrate to evaporate is calculated by a computer and can be precisely controlled. Then the corneal flap is closed and the surgery is complete.