What Should I Know about Vision Correction Surgery?

From the initial removal of glasses, to the hope of improving vision, to the ultimate goal of improving overall visual quality and quality of life, people's pursuits have changed dramatically. People are beginning to want good full vision, that is, clear vision at long, medium, and short distances; and good vision in all weather, that is, good visual quality in various brightness and contrast environments; they also want to get most of their lives Time has a suitable visual quality. So some people started to propose that technically, refractive surgery can be done once every 10 years to meet the visual needs of various age groups. Since the 1980s, refractive surgery has undergone a process from development to maturity throughout the world. A large number of practical surgical techniques and more surgical methods are being developed. It is the most challenging for modern ophthalmology. One of the subject directions ^[1] .

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2018-03-02 14:03 Myopia correction surgery puts myopia into the predicament of " quick temptation " 2018-03-02 14:03

China has 600 million myopia patients, ranking first in the world. Myopia correction surgery is widely sought after, and news of poor vision due to surgery is also common. ... more

Overview of myopia correction surgery

From the initial removal of glasses, to the hope of improving vision, to the ultimate goal of improving overall visual quality and quality of life, people's pursuits have changed dramatically. People are beginning to want good full vision, that is, clear vision at long, medium, and short distances; and good vision in all weather, that is, good visual quality in various brightness and contrast environments; Time has a suitable visual quality. So some people started to propose that technically, refractive surgery can be done once every 10 years to meet the visual needs of various age groups. Since the 1980s, refractive surgery has undergone a process from development to maturity throughout the world. A large number of feasible surgical techniques and more surgical methods are being developed. It is the most challenging modern ophthalmology One of the subject directions ^[1] .

Myopia correction surgery

(I) Surface cutting method

1: Excimer Laser Keratotomy (PRK)

Excimer laser keratotomy, introduced in 1983, was a mainstream operation in the early 1990s. Later, due to severe postoperative irritation symptoms, the recovery time was long, and most patients developed corneal subepithelial haze and hormones after surgery. High intraocular pressure has limited its application. In recent years, with the deepening of research, I realized that it has more advantages than its shortcomings (Haze and pain). It is mainly manifested in the large corneal ablation, more corneal thickness, no corneal flap and epithelial flap concurrent Symptoms, postoperative aberrations, and other aspects. Based on the improvement of laser cutting methods and the use of anti-metabolic drugs, the improved excimer laser keratotomy has the possibility of resurgence.

2: Excimer laser corneal epithelial lavage (LASEK)

Excimer laser corneal epithelial lavage was first reported by Camellin in Italy in 1999. It has most of the benefits of excimer laser keratotomy and does not have an eye-catching effect, but alcohol has damage to tissue and is affected by operation Large, the difference between different surgeons, alcohol concentration, time and anesthetic usage is not easy to accurately control, individual patients have large differences, there are complications of epithelial flaps, Haze phenomenon can still be common. With the advent of the surgical method of mechanical excimer laser corneal epithelial lavage, it may be replaced by mechanical excimer laser corneal epithelial lavage or modified excimer laser keratotomy.

3: Mechanical Excimer Laser Epithelial Keratomileusis (Epi-LASIK)

A mechanical excimer laser corneal subcutaneous flap inlay was first reported in August 2003 by Greek doctor Ioannis Pal-likaris. This technique is a new refractive surgery technique developed on the basis of excimer laser subepithelial flap incision. The corneal epithelium is made by separating the corneal epithelium with a special corneal epithelial knife, which changes the In the excimer laser corneal epithelial lavage operation, the large difference in the effect of 20% alcohol on the individual makes the operation difficult, and at the same time avoids the chemical toxicity of ethanol, so the postoperative irritation symptoms are small and almost no Haze is formed, and the incidence of myopia regression is low, so it is considered to be a promising new excimer laser corneal refractive surgery method.

(B), the method of laser in situ keratomileusis under the stromal flap

1: Laser in situ keratomileusis (LASIK) under the stromal flap

It has been applied to refractive surgery by Pallikaris since 1991, and is currently the most mature and widely used refractive method. Laser in situ keratomileusis under the stromal flap has become the mainstream of refractive surgery due to its more accurate surgical results and faster vision recovery. But at the same time, excimer laser in situ keratomileusis surgery under the stromal flap is also more complicated and difficult, and there are many complications during and after the operation, especially the increase of complications of the corneal flap. Attention of the majority of refractive surgeons.

2: femtosecond laser (Intralase)

The femtosecond laser was first approved by the US FDA for clinical lamellar corneal surgery in January 2000. Its application in refractive surgery mainly began in 2002 and was introduced into China in 2005. At present, it is mainly used in LASIK and LASIK. Epi-LASIK surgery to make corneal flaps. IntraLase, also known as femtosecond laser, is an infrared laser that operates in pulses. Its wavelength is 1053nm, the pulse time is 10-15s, and the diameter of the laser spot is 3-12mm. Air bubbles form cutting surfaces through expansion, fusion, and light rupture. There is no thermal damage or shock wave damage to adjacent tissues. Compared with lamellar flaps produced by mechanical microkeratome blades, femtosecond lasers have many advantages, specifically: the thickness of the corneal flaps produced by femtosecond lasers has high uniformity, accuracy and consistency; flap making Not affected by the curvature of the cornea; femtosecond lasers allow a wider range of surgery and safer surgery. The application of femtosecond lasers has taken refractive surgery a step forward.

3: Anterior Elastic Keratomileusis (SBK)

It is a surgical operation that uses a disposable microkeratome to make an ultra-thin flap with a thickness of approximately retained, and performs laser cutting under the anterior corneal elastic layer. Compared with surface surgery, which retains the anterior elastic layer, the biomechanics is better, and the flap is very thin, without losing deeper fibers. Compared with traditional LASIK surgery, it retains more corneal stromal beds to prevent postoperative corneal expansion. And the occurrence of iatrogenic keratoconus. With its unique advantages, SBK is becoming the focus of current corneal refractive surgery research. SBK is similar to LASIK, but it has a thin corneal flap and can provide the same biomechanical advantages as PRK.

(3) Corneal Stromal Ring Implantation (ICRS)

Corneal stromal ring implantation is a kind of refractive surgery in which polymethyl methacrylate (PMMA) half rings of different thickness are implanted into the central corneal stroma 2/3 deep to change the radius of corneal curvature. Because it does not damage the central optical region of the cornea, clinical applications have shown for many years that it has reversibility and adjustability, good predictability, and no serious complications. It is one of the effective and safe procedures for correcting low to moderate myopia and can be used as a cornea Complement of refractive surgery, such as low and moderate myopia of cornea, and undercorrection of cornea after corneal laser surgery, in the past year should also be used for the treatment of keratoconus.

(IV) Cross-linking

The principle is to add a substance to the corneal stroma, and irradiate it with a specific wavelength of light to crosslink it with the corneal colloidal components to change or enhance the corneal tension and curvature to achieve the effect of treating keratoconus or correcting myopia. For many years, it has entered the stage of clinical research.

(5) Laser asthmatic kemtoplasty (LTK) and conductive keratoplasty (CK) for long-sightedness. LTK and CK use laser or current to generate thermal energy to shrink the matrix collagen in the treatment area, thereby changing the cornea. A technique for correcting hypermetropia while refraction. The CK and LTK treatment areas are outside the optical area; the operation is simple and technically easy to grasp; there are no complications of flaps and no loss of corneal tissue. CK and LTK, as newly developed hyperopia correction surgery, can not completely replace hyperopia LASIK and intraocular lens implantation, but it is safe, economical, and good postoperative visual quality. A wise choice.

(6) Refractive Lens Exchange (RLE)

Due to the success of excimer laser surgery, refractive surgery is gaining popularity. Corneal refractive surgery has its shortcomings, and is not the best choice for high myopia and hyperopia, so it causes resuscitation of lens surgery. In terms of optics, lens refractive surgery is the best way to effectively obtain an orthographic optical system. The appearance of multifocal lenses, aspheric lenses, accommodating lenses, light-controlling accommodating lenses, and memory lenses may be the best choice to eliminate refractive errors and presbyopia.

(VII) Phacoic ICL

Loss of regulation is a major problem with lens replacement. Therefore, a series of intraocular lenses have been developed. The phakic intraocular lens implantation has been carried out for more than 20 years in Europe and the United States. Complications such as corneal endothelial cell injury, cataract formation, and anterior chamber inflammation occurred early in the postoperative period, which made the operation slow. In the past 10 years, a large number of scholars have made a series of improvements in the design and materials of phakic intraocular lens (PIOL) in response to various complications, so that the surgical complications are greatly reduced, so that PIOL implantation has regained everyone's attention.

(8) Presbyopia surgery

Presbyopia surgery can be performed in three ways: cornea, intraocular and sclera. At present, the clinical application of the laser method of multifocal cutting to treat presbyopia has obtained gratifying results. The basic principle of multifocal cutting for presbyopia is to combine the factors such as pupil size, central area, and peripheral area to form a personalized aspheric curve on the corneal surface to expand the depth of focus. The central area is steep to provide near vision, and the peripheral area targets are used for far vision. In addition to multifocal cutting for the treatment of presbyopia, there is also a surgical method for treating presbyopia by increasing negative spherical aberration. The principle is basically the same as that of multifocal cutting, that is, to expand the depth of focus, and it is currently in clinical research.

(IX) Posterior scleral reinforcement

This type of surgery is simple and easy, and the short-term effect is satisfactory. The long-term effect needs to be observed. Most scholars believe that this operation is safe and effective, can inhibit the progression of high myopia, reduce the refractive power of myopia, and improve vision, which is one of the effective prevention and treatment methods for high myopia. There are many benefits of retroscleral reinforcement for progressive myopia (or pathological myopia) before any other suitable refractive surgery is performed in combination.

Preparing for myopia correction surgery

(1) Inquiry of medical history: First, ask the patient if he has a history of myopia development in the past two years. If there is no surgery, then if he wears contact lenses, because contact lenses will affect the shape of the cornea, it is generally necessary to stop wearing for several weeks. Examination and surgery are available. Inquire in detail about allergies, family history, and history of ocular trauma and eye surgery in order to determine whether surgery and possible complications may occur. Understand the general condition of the patient, exclude systemic immune system diseases such as hyperthyroidism, rheumatism, etc., eye diseases: such as dry eye, retinal detachment, glaucoma, etc. and severe diabetes, immune deficiency diseases are not suitable for surgery, special periods such as pregnancy, Breastfeeding or hormone users should postpone surgery.

(II) Psychological preparation: Refractive surgery is performed on normal eyeballs. The purpose of surgery is to correct refractive errors and relieve the trouble caused by glasses. Therefore, most patients have high expectations for the effect of postoperative surgery and psychological burden. Heavier, especially worried about whether the surgery will cause adverse effects or complications on the eyes and the complex psychology caused by the lack of understanding of the surgical process. There are also some patients who have some doubts about the operation, such as whether the surgical instruments are advanced or not, whether the surgeon's clinical experience is rich, and how effective the operation is. For different psychological activities of patients, clinicians and nurses generally take corresponding nursing measures, including: first, using a gentle and encouraging tone to communicate with patients, more ideological communication with patients, providing correct guidance to patients, explaining the surgical process Precautions to understand the surgical methods, precautions, advantages and disadvantages of the surgery, and to properly treat the results of the surgery, so that patients have more adequate mental preparation, and eliminate fear, anxiety, and anxiety. Fully respect the patient's right to know and choose to gain patient trust and increase their understanding and confidence in surgery. Let the patient read the operation instructions carefully and watch the operation publicity video. The patient can observe the whole process of the operation before the operation, understand the steps in the operation, make him fully prepared, and accept the operation with the best psychological state.

(3) Preoperative examination: The naked eye vision, corrected vision, and refractive error should be checked before the operation, and the patients should be tested for intraocular pressure measurement, corneal curvature, corneal topography, corneal thickness measurement, and cooperate with the doctor to make a slit lamp. Examination, fundus examination, and mydriatic optometry, etc., determine whether the patient can undergo surgery and design a surgical plan after a systematic inspection.

Preoperative examination items:

1.Visual inspection

Including naked eye vision and best corrected vision with glasses.

2.Intraocular pressure check

To exclude the possibility of high intraocular pressure and glaucoma.

3.Refractive examination

Including computer optometry, medical optometry and mydriatic optometry. The correctness of the optometry directly affects the effect of surgery.

4. Anterior segment and fundus examination

Focus on checking the corneal transparency, whether there is a scar on the cornea, whether the crystals are cloudy, and whether the fundus is cloudy, vitreous, or fundus lesions.

5, wavefront aberration check

In addition to the presence of low-order aberrations such as nearsightedness, farsightedness, and astigmatism, check whether there are high-order aberrations that seriously affect visual quality, and collect high-order aberration data as the basis for diagnosis and surgery.

Corneal curvature check

Eliminate the possibility of keratoconus and flat cornea.

Corneal thickness measurement

If the patient is highly myopic, attention should be paid to the depth of corneal central cutting and the patient should be informed about the situation before surgery.

8. Corneal topographic examination

The main purpose is to understand the regularity and symmetry of the entire corneal surface, and to exclude abnormal conditions such as keratoconus.

(IV) Eye preparation

1: Drop antibiotic eye drops before surgery to prevent infection;

2: Instruct patients to perform eye fixation training so as to cooperate well during the operation;

3: On the day before the surgery, the patient was instructed to fall asleep as early as possible to maintain a good mood and clean personally. On the day of the surgery, clean the head and face, wash off greasy, disable cosmetics on the eyes, and prohibit perfumes and hair sprays.

4: Clean the skin around the eyes before surgery. Rinse the conjunctival sac with normal saline and gentamicin solution, and disinfect the skin with iodine. Do not let the disinfectant enter the conjunctival sac or contact the corneal surface.

5: The patient closed his eyes and rested in preparation for surgery.

Myopia correction surgery laser surgery process

First, before surgery

Before surgery, the doctor will use sterile saline and chloramphenicol eye drops for eye washing for about 5 to 10 minutes to reduce or avoid the chance of eye infections.

Intraoperative

1. Anesthesia eye. At the beginning of the operation, order anesthesia eye drops. A special anesthetic is dropped on the eyeball to make it lose pain, but the touch will still exist.

2. Making a corneal flap. First, the eyelid opener helps patients open their eyes during the entire laser treatment of myopia. Then the doctor put a suction ring on the stretched eyeball to make a corneal flap. The process is only a few seconds, and the patient may feel a sense of pressure on the eyeballs, or a temporary loss of vision, a sense of darkness, and some pain.

3. Laser carving. After the corneal flap is made, the doctor gently lifts the corneal flap with a triangular sponge, and according to the data entered by the laser treatment instrument, the cornea is carved with a laser. The cutting area with deep myopia is correspondingly larger and takes longer.

At this time, there will be a series of light sounds and a little burning odor, so the patient need not worry. This is a normal photochemical reaction when the laser is working. It should also be noted that although the laser can track the minute movements of the eyeball in 1/10 seconds, it is best to keep your eyes fixed as required by the doctor in this process.

After carving, the doctor covers the corneal flap with a sponge and rinses the eyes. The surgery is done for one eye, and then the other eye is done in the same way.

4. The operation is completed. The doctor will use a slit lamp microscope to check the corneal flap reduction.

Precautions during myopia correction surgery

(1) Operating room environment The constant temperature of the operating room guarantees the success of the operation. Too high a room temperature can affect the laser energy, while too low a temperature can cause excessive refractive error. Avoid using volatile substances such as alcohol and perfume in the operating room to avoid It affects the output energy of the laser.

(2) Check the patient's name, gender, age, surgical eyes and refractive power. Give the patient some necessary explanations to familiarize the patient with the sound, brightness and scorch smell generated by the laser machine when the laser machine is working, reduce the tension of the patient, prepare the patient psychologically, actively cooperate with the doctor to perform the operation, and avoid The patient's nervousness caused involuntary eyeball rotation and body tremor, resulting in irregular laser cutting.

(3) The patient's head position should be well placed. The patient should be in the supine position. The eyes should be aligned with the excimer laser horizontal line. The forehead, nose, jaw, and midline of the body should be in a vertical horizontal line. Keep your head upright so that the green reflective spot is at the center of the cornea. During the operation, the patient was instructed to look at the green light spot directly above to avoid eyeball rotation. Due to the increase in intraocular pressure during negative pressure suction, the patient's eyeballs may have a feeling of swelling and pupil dilation. At this time, the eyeballs should be kept still, so as to avoid tension and discomfort caused by eyeball rotation and negative pressure suction failure. After the corneal flap is made, closely observe the changes in the patient's head position. The deflection of the patient's head position can cause the deflection of the eye position, so that the center of the laser cutting area is deviated from the center of the pupil. The deflection of the head position can also cause the astigmatism axis to shift during laser cutting and cause irregular astigmatism after surgery. Therefore, during the operation, adjust to determine the correct head position, and then perform laser cutting.

(IV) Immediately after the operation, check under a slit lamp microscope to observe whether there are particles and debris under the corneal flap, and whether the corneal flap is flat and flat. If foreign matter is found under the valve, the patient should be flushed in time to remove debris and particles to ensure that the cornea is transparent after surgery. After the eye drops, wear a clean transparent eye mask to inform patients that due to the use of surface anesthesia, there will be foreign body sensation, tears and other discomforts after surgery. These symptoms are normal postoperative reactions and do not need to worry too much. Patients are advised to return for consultation time and precautions. It is strictly forbidden to rub the eyes and force the eyes to prevent the corneal flap from being displaced or wrinkled. Close your eyes and rest as much as possible on the day of surgery to reduce eye reactions. If there is pain or redness, swelling and aching, you should go to the hospital in time.

Nursing after myopia correction surgery

(A), the first day after the observation of the disease must go to the hospital for review, remove the eye mask for the patient, clean the eye with antibiotic eye drops, check the naked eye vision, and carefully observe the corneal flap healing and eye symptoms under a slit lamp microscope, And inform patients: most patients can achieve the best corrected vision on the first day after surgery, and a small number of patients need a week or a month to reach the best corrected vision.

(2) Postoperative medication guides patients to take medications, and explains the precautions for medications: Wash your hands before dropping eyes, use gentle movements during eye drops, and try to avoid touching the upper eyelids as much as possible to prevent excessive manipulation and affect corneal flap repair. Use different eye drops at intervals of 5 minutes. Do not touch the eyelashes and cornea when using the medicine. Cap the bottle at any time after use. Take medicine strictly according to the doctor's advice. Do not stop, reduce or use other medicines without authorization. Otherwise, it will cause adverse consequences and affect vision recovery and stability.

(3) Postoperative review The first day, seventh day, fifteenth day, one month, three months, six months, and one year of post-hospital review will be performed. In case of redness, swelling, pain, photophobia, tearing, or increased secretions, you should seek medical attention in a timely manner.

(4) The main problem that most patients worry about after surgery is that vision fails to achieve the expected results. It should be explained to patients that postoperative vision recovery is a gradual evolution process, which is related to the level of myopia and the difference in personal response to treatment. It is normal to have fluctuations within the month, usually reaching basically stable in three to six months. Some patients are worried that using the eyes early will affect vision recovery. They dare not use the eyes and rest at home with their eyes closed all day. In this case, the meaning of normal eye use should be explained to the patient, and the reasonable use of the eye should be avoided, so as not to affect the normal work and life. Some patients, especially older patients, may feel slightly blurred when looking at nearby objects at the beginning, after which the symptoms will gradually disappear, and individual patients may have temporary eye fatigue and glare after surgery. For these patients, reasonable explanation should be given. Give your heart comfort in time, advise him not to be overly anxious and worried, and relax mentally. Over time, this discomfort will gradually disappear.

Health guidance after myopia correction surgery

(1) Avoid infection: Do not touch the environment that may cause infection, prevent dust and stolen goods from entering the eyes, and do not splash water into the eyes during washing, bathing, and face washing within 2 weeks after surgery. Swimming is prohibited for three months. Keep your eyes clean and hygienic. Do not use cosmetics on your eyes for two weeks. Avoid rubbing your eyes with dirty hands or dirty towels to prevent infection.

(B) Guidance with eyes: Some patients will have myopia blurring within one month. During this period, they should avoid watching mobile phones, TVs and working at close distances for a long time.

(3) Dietary guidance: spicy food, tobacco, and alcohol can make conjunctiva congestion, increase secretion, and aggravate inflammation. Therefore, patients should be encouraged to consume light, digestible foods rich in vitamin A.

(4) Avoiding corneal flap displacement: Forcefully squeezing eyes, rubbing eyes, and trauma may cause corneal flap displacement or wrinkle. Violent and bumpy activities should be avoided within one month after operation to prevent external force collision.

Myopia correction surgery contraindications

Contraindications need to be taken into account when performing vision correction surgery:

Absolute contraindications :

(1) Severe dry eye;

(2) Keratoconus or those with a keratoconus tendency;

(3) Blepharitis;

(4) proliferative diabetic retinopathy;

(5) Exophthalmia, incomplete eyelid closure;

(6) Systemic immune and collagen diseases;

(7) Scar constitution.

Relative contraindications:

(1) Myopia is not suitable for myopia correction;

(2) Do not treat systemic immune and collagen diseases during active periods;

(3) Endothelial cell injury and rejection of the graft may be caused after penetrating corneal transplantation, so it must be used with caution;

(4) For patients with weak corneal epithelial adhesion, try to avoid excimer laser surgery.

Common myths about myopia correction surgery

Misunderstanding 1: Myopia correction surgery will hurt the eyes

The principle of myopia correction surgery is that ultraviolet light is irradiated on the cornea of the eyeball, photochemical action occurs, a small amount of corneal tissue is cut, and the refractive power of the cornea is changed to achieve the purpose of treating myopia. Myopia correction surgery does not penetrate the cornea, and only produces a cutting effect on the surface of the cornea in the irradiation area, so it has no effect on other tissues inside the eyeball.

Myth 2: Myopia will rebound after myopia correction surgery

The so-called "rebound" is medically called "refractive retreat", which refers to the phenomenon that patients have myopia again within a period of time after myopia correction surgery due to individual differences, different types of myopia, and good or bad eye health. This phenomenon is more common in people with ultra-high myopia, and the majority of myopia patients do not change much in power after adulthood, and laser cuts part of the stroma of the cornea, this part of tissue will not regenerate, thus ensuring absolute Most myopia patients have stable results after myopia correction surgery.

Myth 3: Myopia can be corrected

Not all myopia patients can receive myopia correction surgery. Patients with infectious inflammation, keratoconus, glaucoma, cataracts, fundus lesions, etc., or with systemic diseases such as diabetes and connective tissue disease are not suitable for myopia correction surgery.

Myth 4: Myopia correction surgery is a minor operation

Myopia correction surgery is not an ordinary minor operation, and there are certain risks. The health supervision department has a strict evaluation system for admission qualifications of hospitals, and doctors must have equipment employment permits to perform surgery. In addition, there are strict requirements on preoperative inspection equipment, related staffing, myopia correction surgery process management, and other links.

Myth 5: Myopia correction surgery takes a long time to recover

In general, vision can be restored within 1-2 days after surgery. Whether or not you can participate in normal activities depends on the specific circumstances of the patient, the work they are engaged in, and the type of activity to be performed.

Surgery is an ideal method for treating adult refractive error. It is safe, effective, stable, less traumatic, and has a rapid postoperative vision recovery, which can achieve the ideal therapeutic effect. However, since the operation is performed on a healthy cornea, patients generally have high expectations for the postoperative results. Preoperative medical staff should communicate more with the patient and patiently and meticulously introduce the surgical methods and procedures to the patient to make it adequate for the operation. Recognize, eliminate worry and fear. The collection of preoperative medical history and detailed eye examination are also the keys to successful surgery. In addition to cooperating with the doctor's surgery, the patient should be encouraged to relax, not to be nervous, closely observe the changes in his head and eye position, and assist the doctor to adjust in time to avoid affecting the surgical effect. Be vigilant during the entire procedure, every minor care error can bring lifelong pain to the patient. In addition to various objective examinations such as postoperative vision, the success rate of the surgery ultimately depends on the subjective satisfaction of the patient. Therefore, it is necessary to communicate with the patient more after the operation, and make a patient and detailed explanation for the reactions and discomforts that occur after the operation. The idea is to relieve the psychological doubts and eye reactions of patients, strengthen the health education for patients, guide the rational use of medicines, rational use of eyes, and explain various precautions, and try to avoid postoperative complications.