Lasik epi for the correction of myopia. Epi Lasik is a method of laser vision correction. How does laser vision correction work?

Laser vision correction is an eye surgery using a laser aimed at correcting the optical system of the eye apparatus, so that the image is focused directly on the retina - like a person with good vision. With various types of ametropia (and) refraction is impaired: with myopia, the rays from the object of vision converge to one point in front of the retina, with farsightedness - behind the retina, and with astigmatism, the rays do not converge at all into one focus. All this leads to a deterioration in the quality of vision: objects do not look clear.

The optical system of the eye includes the cornea, the humor of the anterior chamber, the vitreous body, as well as. The latter performs the so-called dynamic refraction: as the lens contracts, it changes its shape to a more convex or flatter one, thereby affecting the back focus point.

The remaining structures of the eye listed above relate to static refraction: due to their convex structure and watery structure, they are able to refract passing light.

So the optical power of the cornea is approximately 40 diopters. It is this that is the subject of laser correction. By changing the thickness of the cornea, its curvature changes, as well as its refractive power, which ultimately leads to improved vision.

It is worth noting that Svyatoslav Nikolaevich Fedorov was the first to propose changing the thickness of the cornea. He made micro-incisions on the cornea from the central area to the edges. By analogy with a skin wound, micro-incisions in the cornea healed with slight tension, which ultimately led to a change in the shape of the cornea. Since the cornea is part of the optical system of the eye, following a change in its refractive power, vision improved. But later this method was considered too crude.

What was needed was a thin, almost microscopic instrument that could act more delicately. Filigree work on the cornea became possible using not mechanical technology, but laser technology.

Initially, the laser beam had limited applications and was mainly used in the computer industry. In the mid-eighties, scientists paid attention to this device. The subtle effect failed to impress the doctors. After testing this type of laser on the cornea, its potential in ophthalmic surgery was revealed.

It became possible to perform layer-by-layer removal instead of traumatizing the entire thickness of the cornea. So, with each pulse, a layer is removed, the thickness of which is 500 times less than that of human hair, which provides a good functional result. This fact has led to the widespread use of laser vision correction.

Indications and contraindications

• high degree;
• Low degree hypermetropia;
• Astigmatism.

The criterion for a high degree of myopia is due to the fact that the correction will be the most successful, since in the initial stages of myopia development it is still possible to restore vision using non-surgical methods, and it is also quite difficult to remove a thin layer of the cornea.

With farsightedness, on the contrary, the inclusion criterion is a low degree, since the higher the degree, the more difficult it is to form the necessary curvature of the cornea.

• Not established myopia or hypermetropia;
• Inflammatory eye diseases;
• Degenerative-dystrophic processes in the eyeball;
• Retinal detachment;
• Infectious diseases in the acute period;
• Pregnancy;
• Childhood;
• Having only one eye.

Before performing an operation, an experienced doctor must evaluate all indications and contraindications for surgery.

Types of laser vision correction

PRK is the oldest method and, of course, has many disadvantages. Its main disadvantage is its effect on all layers of the cornea, including the superficial ones. This leads to a longer recovery period, since time is needed for the regeneration of the surface epithelium. For 3-4 days, the patient feels pain and pain in the eyes due to the absence of the protective layer of the cornea. Episodes of lacrimation are frequent. The most serious complication is inflammation of the unprotected part of the cornea, but this usually occurs in rare cases. Also, the use of this method is associated with the risk of partial restoration of vision quality. In approximately 1 operation out of 10, it is not possible to achieve the planned 100% result.

Another unpleasant side of PRK is subepithelial opacification of the cornea. The patient feels fog before the eyes, which led to the name of this complication as haze (from English - fog). It is benign and temporary, although there is evidence that in 1-6% haze does not disappear.

Nevertheless, this method is successfully used today due to significant advantages even over new techniques:

• The lid does not form;
• Less depth of operation;
• Inexpensive;
• It is carried out quickly.

It would seem that the impact on all layers is more of a minus than a plus. In fact, the formation of the cap is associated with a number of limitations.

First, it is quite difficult to cut out a corneal flap of the required thickness in people with thin corneas. Even if this is successful, the flap does not always remain viable. Recovery in this case takes even longer than with complete damage to the surface layers.

Secondly, despite the fact that the corneal flap fuses with the remaining part, a small scar becomes noticeable within a year. This is an inconvenience for people who would like to hide the fact of having laser surgery. For example, for pilots who are subject to periodic ophthalmological examinations, it is preferable to use PRK.

The shallower depth of the operation allows it to be used on low and medium degrees of myopia. Adjustments also become possible. It is worth noting that this fact is the main advantage over the LASIK technique. Sometimes it is more convenient to perform PRK and then correct the results obtained than to remove the middle layer of the cornea once and for all.

The relatively lower cost and speed of the operation is certainly a plus.

LASIK

Laser vision correction using the LASIK method (LASIK) rightfully occupies a leading position in terms of frequency of implementation.

• Less pain;
• Shorter postoperative period.

But the operation cannot be performed on a thin cornea (less than 500 microns). There are also cases of turbidity, but only in deeper layers. Deformation of the corneal flap, as well as injury to the cornea during its formation, is possible. The risk of developing inflammatory complications inside the cornea cannot be excluded.

As a result of cutting out the flap, the supporting integrity of the cornea is disrupted. Like a convex dome, when its central element is damaged, its peripheral parts collapse. The same thing happens to the cornea and is called protrusion.

Additional vision correction is not possible. Existing problems can be solved using the EPI-LASIK technique.

EPI-LASIK

The difference between the EPI-LASIK surgery technique is the formation of a corneal window. It is not a blade that is used, as in LASIK, but an epikeratome. He separates the flap along natural lines, as if gently tearing it away from the base layer. This ensures a more natural and soft recovery

The advantage is the formation of a thinner flap, which is especially important for patients with thin corneas. However, classical EPI-LASIK can be performed in less than 50% of operations. This is due to the individual characteristics of the cornea. The structure of the cornea is known to be affected by the use of soft contact lenses. Considering that most candidates for laser surgery are people who refuse glasses in favor of lenses, it can be quite difficult to find a suitable patient.

Thus, all three methods of laser correction can be used equally, taking into account indications and contraindications. The ophthalmic surgeon must be familiar with all techniques and choose the most suitable method for a particular patient.

How does laser vision correction work?

At the moment, there are several methods of laser vision correction, which will be discussed below, but the essence of them is the same: the effect on the cornea.

Photorefractive keratectomy (PRK)

Laser vision correction using the method of photorefractive keratectomy (PRK) consists in the fact that the laser evaporates tissue on the surface of the cornea with high precision, which leads to a change in its curvature.

Unlike Fedorov's method, PRK is painless and relatively safe, and is still used today. Subsequently, it was found that it is more effective to act on the middle layers of the cornea, while preserving the superficial layers, which does not happen with PRK. This became possible in 1989 with the advent of LASIK. The essence of the method is laser keratomyelosis. This is exactly what the abbreviation stands for. The innovation of the technology consists in the formation of a kind of defect on the leg, which folds to the side like a manhole cover. In this way, the middle layers of the cornea become accessible for laser treatment, after which the main laser correction takes place.

• Formation of a corneal flap using a special device - a microscopic keratome. The device is placed perpendicular to the eyeball on the cornea area. Then there is a flash of light, which the doctor usually warns about. It is at this moment that the flap is cut out;
• Retracting the corneal flap to the side and opening the middle layers of the cornea;
• Laser exposure;
• Returning the corneal flap to its place.

LASIK

When performing LASIK surgery, the corneal flap does not need to be sutured; the cornea heals on its own in a short period, subject to the rules of the postoperative period. During LASIK surgery, the corneal epithelium is not preserved, which makes the postoperative period painful.

EPI-LASIK

The preservation of the corneal epithelium during laser vision correction led to the emergence of a new technique - Epi-LASIK, which was first used in 2003. The new technology has adopted the essence of the previous one, incorporating some improvements.

Its distinctive feature is a thinner corneal flap. The window in the cornea is formed using an epikeratome. Subsequently, the corneal flap is also returned to its place. Due to the preserved epithelial layer, better tissue repair is achieved. During the early postoperative period, wearing a protective contact lens is indicated.

Advantages and disadvantages of laser vision correction

Of course, the benefits of laser correction cannot be underestimated! Vision returns. Of course, it is possible to see the world clearly using glasses or lenses.

• they can be lost or forgotten;
• fog up in the cold;
• cause inconvenience during active physical activity;
• cannot be used underwater.

Glasses also affect your appearance. Despite the fact that glasses are now an element of style, not everyone supports this fashion.
Greater comfort and the illusion of preserved vision are observed when using contact lenses. Modern lines are extremely easy to use and almost invisible when worn.

However, they are quite expensive, they must be removed during sleep, and they cannot be worn for a long time without rest. If personal hygiene rules are not followed, various inflammatory diseases are possible. Thus, the undeniable advantage of laser vision correction is the restoration of vision quality.

• This is an operation that, like any surgical intervention, is associated with the risk of injury to the eyeball;
• High cost;
• Progression of myopia.

The fact is that two factors are responsible for the development of myopia: flattening of the eyeball due to a defect in the connective tissue that makes up its frame, or weakness of the ligamentous apparatus of the lens. One way or another, despite vision correction, myopia will progress, just at a slower rate.

Limitations after laser vision correction

The postoperative period after laser correction has many limitations. The main task of this stage is to allow the eyes to rest and recover effectively.

• Wash and touch your eyes
• Use cosmetics;
• Strain your visual apparatus (any type of reading, needlework, watching TV, etc. is excluded).

• Visit ponds, baths, saunas, swimming pools;
• Exercise;
• Drink alcohol;
• Smoking;
• Look at a source of bright light (applies to the rays of a strobe light, fireworks);
• Get pregnant.

It is also necessary to avoid exposure to direct sunlight, and therefore it is recommended to wear sunglasses even in cloudy weather. A number of other restrictions may be added to the above list at the discretion of the attending physician.

Rehabilitation after laser correction

Rehabilitation after laser correction takes approximately the first six months, during which restrictions must be strictly observed, and, if necessary, continues for up to a year. After this period, one can reasonably judge the effectiveness of the surgical intervention.

Thus, laser vision correction is an excellent way to improve the quality of vision, but it must be remembered that it is not a panacea. In 15-20 years, or even earlier, the effect of the surgical intervention will disappear, and vision will begin to deteriorate again.

Also, the operation does not affect degenerative changes in the retina, which progress despite the surgically achieved 100% visual acuity. Therefore, it is much easier and more effective to protect your eyesight from a young age: follow a work and rest schedule, do not read or watch TV in the dark, and perform special exercises.

Epi LASIK– one of the modern methods of excimer laser vision correction. Developed by the “pioneer” of the LASIK technique, the Greek ophthalmic surgeon Ioannis Pollikaris in 2003, Epi-LASIK, due to its key differences, became a logical solution to the problems associated with LASIK and LASEK operations.

LASIK, LASEK, Epi-LASIK

LASIK surgery, as a method of laser vision correction, involves cutting the surface layer of the cornea to create access for the laser beam to deep tissues. This section is performed manually by an ophthalmic surgeon using a special device - a microkeratome. And although modern medical technology minimizes the possibility of complications, sometimes the surgeon’s actions involve the loss of a corneal flap or its incomplete cutting.

In the LASEK technique, this procedure is performed by applying an alcohol solution, the use of which can also lead to negative consequences.

According to the Epi-LASIK technique, a specially designed device, the epikeratome, is used to simulate a corneal flap. It is capable of separating the corneal epithelium along the anatomical border of its layers. This innovation completely eliminated the risk of flap displacement, as well as the negative impact of alcohol solutions on corneal tissue cells.

The further process of surgical intervention does not differ in any way from the current methods of laser vision correction. The resulting flap of cornea is moved to the side by the surgeon and the excimer laser, by evaporating the tissue, changes the shape of the cornea, correcting the refractive error. At the end of the surgical procedures, the corneal valve is restored to its original boundaries, and a special lens is installed on the eye, which will accelerate the regeneration of the epithelium and protect the intervention site from outside influence.

It should be noted that due to the design features of the epikeratome, the EpiLASIK technique is best suited for patients with mild and moderate degrees of myopia. This is explained by the flattened shape of their cornea, in contrast to patients with high degrees of myopia, whose cornea has a more spherical shape and creates certain difficulties for the operation of the device.

At the same time, vision recovery after Epi-LASIK is much longer than after LASIK, when the result is felt literally the next day, and complete vision recovery takes only a few weeks.

When is Epi-LASIK indicated?

The vast majority of excimer laser vision correction cases in the world are performed using the LASIK technique. However, for a number of indications, its implementation is impossible, then EpiLASIK surgery becomes a worthy alternative.

The main indication for Epi-LASIK correction is the patient’s corneal thickness insufficient for LASIK. In addition, according to experts, Epi Lasik is preferable for people who lead an active lifestyle or have professions that involve risk: athletes, military personnel, firefighters, and rescuers. After all, this operation completely eliminates displacement of the corneal valve, which is possible in case of injury after LASIK surgery.

Epi-LASIK postoperative period

Postoperative discomfort of Epi-Lasik can be associated with pain in the eyes, lacrimation, and the feeling of sand getting into the eye. True, patients are bothered by such manifestations to a much lesser extent than after performing PRK and LASEK. In addition, drops prescribed after surgery contribute to their rapid disappearance. Restorative epithelization of the cornea is usually completed by the third postoperative day and the protective lens is removed.

By this time, patients usually have 50% of their final visual acuity, and after a week they can already drive. Often, the effect of the operation is not fully apparent immediately, and improvement in vision occurs gradually, over several months, which is considered the norm.

The absence of negative consequences and the best result of Epi-LASIK surgery, as a rule, depend on the discipline of the patient. After all, it is on him that the careful fulfillment of the attending physician’s instructions, adherence to the examination schedule and adherence to the postoperative treatment regimen with the given drops depend.

Epi-LASIK is one of the varieties of LASIK laser vision correction technique widely used in ophthalmology. While maintaining all the advantages of basic treatment (high efficiency, safety and painlessness, quick recovery), the method allows the correction of myopia, farsightedness and astigmatism even for patients with thin corneas.

One of the key stages of laser vision correction is the separation of the upper corneal layer and the formation of an epithelial flap to provide access to the middle layers of the cornea. Until recently, only patients with sufficiently thick corneas could qualify for such treatment. Some eye pathologies (higher order aberrations, dry eye syndrome, thin cornea) were a contraindication to vision restoration using a laser. Such patients had to either refuse correction altogether or undergo surgery using PRK (photorefractive keratectomy) or LASEK (laser subepithelial keratectomy). Significant discomfort during the procedure and long-term rehabilitation became the reason for many to refuse treatment.

Based on the needs of such patients, another method of laser vision correction was developed - Epi-LASIK. It combines the advantages of LASIK and the possibility of affecting even eyes with problematic corneas. Painlessness, rapid restoration of visual function and safety of this technique have significantly expanded the range of patients who can count on laser vision correction.

Limits of application of laser vision correction using the EPI-LASIK method:

• ​ Myopia up to - 10.0 D
• ​ Myopic astigmatism up to −4.0 D
• ​ Hypermetropia up to + 6.0 D
• ​ Hypermetropic astigmatism up to +4 D

Stages of laser vision correction using the EPI-LASIK method

1. ​ Instillation of an anesthetic directly into the eye without the use of intramuscular or intravenous anesthesia.
2. ​ After the anesthesia takes effect, an eyelid dilator is installed to prevent blinking and other involuntary movements of the eyelids.
3. ​ Using an epikeratome, a thin corneal flap is separated, including only epithelial cells. The epithelial keratome, unlike the microkeratome, does not have a blade. It exfoliates the cornea very precisely and ultra-finely.
4. ​ Laser correction of the surface of the cornea located under the separated epithelial flap is performed.
5. ​ The final stage of the operation does not require stitches. The epithelial flap is placed in its original location and covered with a protective contact lens to promote rapid healing. Depending on the rate of recovery, the lens is removed 3-5 days after surgery.
6. ​ If necessary, correction is carried out in the same way on the second eye.

Video about Epi-LASIK Epi-Lasik (Ephithelial LASIK)

Advantages of the Epi-LASIK technique:

1. ​ Visual functions are restored immediately after correction;
2. ​ The integrity of the corneal structure is not affected;
3. ​ The superficial flap is formed without incisions using a steel surgical instrument;
4. ​ The epithelial sheet is formed without the use of alcohol and retains high viability;
5. ​ Correction is indicated even for thin corneas and a number of other disorders;
6. ​ The corneal epithelium is restored completely;
7. ​ Postoperative subepithelial opacities are unlikely;
8. ​ Discomfort during the procedure is insignificant and is predominantly psychological in nature.

Results

Observations of patients after correction using the Epi-LASIK method showed effectiveness and safety. Maximum vision recovery occurs 2-3 days after the procedure. Discomfort and pain experienced by patients during treatment and rehabilitation are, on average, subjectively assessed at 1.34 points on a 10-point scale, where “0” is the absolute absence of pain, “10” is the maximum possible pain.

Since recovery after correction largely depends on the first stage of the procedure - separation of the corneal sheet - the technique of its formation, affecting only the most superficial epithelial layers, plays a significant positive role here. During this stage, Epi-LASIK ensures minimal tissue resistance and preservation of viability in about 80% of corneal cells.

Safety

Long-term observations have shown that during thousands of laser vision correction operations using the Epi-LASIK method, there was not a single case of serious complications, such as dissection of the stroma or perforation of the flap in the center of the optical zone. There were also no cases of significant corneal opacity after surgery. These data confirm the safety and predictability of this vision restoration.

Postoperative recovery during correction using the Epi-LASIK method

According to statistics, 97% of laser vision correction operations using the Epi-LASIK method lead to excellent results in terms of the quality of the flap and stromal bed. In all cases, the epithelium was completely restored. about 90% of operated patients were ready to return to work within 2-3 days after laser vision correction.

Epi-LASIK is a laser vision correction method that combines the advantages of PRK and LASIK.

This procedure - an advanced type of corneal surface ablation for the correction of myopia, farsightedness and astigmatism.

The goal of the procedure is to reduce post-operative pain, speed up healing, achieve better vision and reduce the risk of side effects.

Indications for surgery

The procedure allows you to restore vision without using glasses or contact lenses. Shown:

• patients over 18 years of age with refractive errors - myopia, astigmatism, hypermetropia;
• if the acuity of visual perception has not changed over the past year;
• if the disease worsens vision and progresses;
• if there are no other eye health problems that are a contraindication to laser correction.

Additionally, if the doctor has said that the patient is not a candidate for LASIK due to a thin cornea, then Epi-LASIK is an excellent opportunity to improve visual perception.

Contraindications

The procedure is not performed on women during pregnancy and breastfeeding. Epi-LASIK is contraindicated in patients with Bowman's membrane striae or a history of corneal surgery.

This operation is suitable:

• if the patient suffers from eye diseases or pathologies of the retina/optic nerve (keratoconus, glaucoma, cataracts, cornea, herpes, herpes zoster);
• if you have autoimmune diseases (multiple sclerosis, rheumatoid arthritis, lupus);
• in the presence of diabetes, collagen vascular diseases.

Laser correction is not performed if the patient is taking steroids or immunosuppressants.

Benefits of Epi Lasik surgery

The advantages of the procedure include:

• Provides a more predictable result because it can induce third order aberrations.
• Unlike LASIK, it does not require the creation of a corneal flap, thereby avoiding scarring, malunion, inflammation and infection. The epithelial cells remain intact and protect the main treatment area from inflammation and rupture.
• Suitable for active athletes. You are allowed to return to contact sports two weeks after surgery.
• Less likely to cause dry eyes.
• Considered a second chance for patients with thin corneas. If the patient has a thin cornea, the usual laser correction procedure is contraindicated, but this one is the best choice.
• Suitable for patients with high myopia. There is no need to create a flap.
• Less risk of developing blurred vision.

Price

The cost of laser correction using modern equipment ranges from 14 to 57 thousand rubles.

Preparatory procedures before surgery

Before going to see an ophthalmologist, it is recommended that you stop using contact lenses for four weeks and switch to wearing glasses. Wearing contact lenses over a long period of time changes the shape of the cornea. Then it takes a long time to take its natural shape.

Therefore, surgical intervention on a cornea that has not taken its natural shape has negative consequences.

During the examination, you should discuss with your doctor all the risks, complications and rehabilitation period.

Doctors usually advise Epi LASIK if the patient is an unsuitable candidate for LASIK.

On the day of surgery:

• Avoid applying cream, lotion or makeup to your face;
• stop taking any cold or allergy medications 4 days before surgery;
• stop smoking and drinking alcohol 48 hours before and after surgery;
• on the day of laser correction, do not take insulin if the patient is diabetic;
• arrange a trip home after the procedure.

Description of the Epi Lasik operation

Operation stages

Step-by-step procedure:

1. instill the anesthetic drug several times at intervals of 1–3 minutes;
2. an epithelial flap is created by separating the upper epithelial layer from the cornea;
3. moves to the side;
4. excimer laser changes the structure of the cornea;
5. the epithelial flap returns to its original position.

A bandage is applied and will be removed after a few days.

After the procedure, the patient will receive a prescription for pain-relieving eye drops - usually anti-inflammatory drugs and an antibiotic to reduce the risk of infection.

Rehabilitation after Epi Lasik surgery

Recovery from Epi-LASIK is generally similar to recovery from conventional laser surgery.. It is important that patients are transferred from the surgical facility after the procedure, as vision will be blurry after surgery.

After surgery:

• do not rub your eyes;
• wear sunglasses;
• do not visit the pool and open water bodies;
• do not go to the sauna or steam bath;
• refrain from visiting the solarium;
• use drops prescribed by an ophthalmic surgeon.

Complications

Serious complications with Epi-LASIK are extremely rare.

Epi-LASIK is a safe, effective and permanent procedure, but like any surgical procedure, there are some risks. The risks and complications associated with this procedure are reduced or eliminated through careful patient selection and preoperative testing using the latest diagnostic technologies.

Complications:

• poor night vision;
• glare or halos around light sources;
• increased sensitivity of the eyes to sources of artificial and natural light;
• scarring of the cornea;
• infection.

Effect after Epi Lasik surgery - is it worth doing?

Epi-LASIK results are comparable to traditional LASIK, meaning much less reliance on corrective lenses and clearer vision. This is a testament to the advancements in vision correction technology and surgical techniques over the years.

It will take 6–7 months for the eyes to heal completely. Epi LASIK requires a slightly longer recovery period than LASIK.

The results of the operation are permanent. However, laser correction cannot prevent the natural deterioration of vision that happens over time.