Anterior layered keratoplasty (DALK). Posterior layered keratoplasty Keratoplasty types of indications

Keratoplasty is a microsurgical procedure that makes it possible to restore visual function in patients with corneal diseases. Keratoplasty allows you to eliminate congenital and acquired pathologies, restore the functions of the cornea and its shape.

Corneal diseases:

1. Congenital developmental defects: megalocornea (enlarged cornea), microcornea (reduced cornea), keratoconus (conical shape), keratoglobus (spherical shape).
2. Inflammatory processes: (fungal, viral, bacterial). There are deep and superficial inflammations, endogenous and exogenous.
3. dystrophic conditions. This group includes diseases that develop with metabolic disorders, changes in the structure of the cornea, changes in properties. There are primary and secondary dystrophic pathologies.

Corneal transplantation is called keratoplasty. During the operation, the deformed area of ​​the cornea is replaced with a donor graft. Partial or complete replacement is possible, as well as transplantation to the entire depth of the cornea, to the anterior layers or to the thickness.

Features of the cornea

The cornea is the transparent outer layer of the eye. The shape of the stratum corneum resembles the glass in a watch. In terms of functionality, the cornea is the basis of the optical system of the eye.

The cornea is a convex-concave transparent lens, which is 1/5 of the outer shell of the eyeball. Due to its transparency, light can penetrate deep into the eye to the retina. The border of the transition of the cornea to the sclera is called the limbus.

Corneal signs:

• sphericity;
• sensitivity;
• transparency;
• specularity;
• absence of blood vessels.

In the center, the thickness of the cornea reaches 500 microns, along the edges up to 750 microns. Normally, the radius of curvature is 7.7 mm, the refractive power of the cornea is 41 diopters at 11 mm of horizontal diameter.

Cornea layer:

1. The anterior epithelium includes 5-6 layers of rapidly regenerating cells that maintain the shape of the cornea and provide optical function. This layer protects the cornea and eye from the external environment. Gas and heat exchange is carried out through the anterior epithelium.
2. Bowman's membrane is located under the epithelium. This layer is dense, it is designed to maintain the shape of the cornea. Bowman's membrane provides resistance to mechanical stress.
3. The stroma is the thickest layer. It includes plates of collagen fibers and other cells (leukocytes, fibrocytes, keratocytes).
4. Descemet's membrane is composed of fibrils similar to collagen. The layer fights infections and thermal effects.
5. The posterior epithelium is the inner layer and includes hexagonal cells. The cornea is fed from intraocular fluid through the posterior epithelium. When this layer is deformed, swelling of the cornea develops.

It is noteworthy that the cornea is devoid of blood vessels, it receives all the nutrients from the intraocular and lacrimal fluid. Metabolic processes are also carried out through the vessels around the cornea. It is the absence of blood vessels that makes it possible to successfully carry out corneal transplantation (keratoplasty).

Functions of the cornea:

• protective and supporting, due to its strength, sensitivity and rapid regeneration;
• light transmission and light refraction due to transparency and sphericity.

Indications for corneal transplant surgery

Among all diseases of the visual system, pathologies of the cornea make up a quarter. Often, corneal diseases provoke irreversible deterioration in visual function. The danger of pathologies of this part of the eye lies in the fact that most of them cannot be corrected with glasses and contact lenses. For this reason, keratoplasty is considered almost the only way to restore vision to patients with corneal clouding or changes in its sphericity.

Indications for corneal transplantation:

• keratoconus (non-inflammatory pathology in which the cornea takes a conical shape and gradually becomes thinner);
• keratoglobus (non-inflammatory pathology, in which the corneal stroma becomes thinner and protrudes, which leads to its globus-shaped deformation);
• avascular leukoma of the cornea (clouding that occurs during trauma, inflammation, chemical or thermal burns, complication of keratitis or ulcers);
• post-traumatic scars (the result of inflammation or surgery);
• corneal dystrophy (congenital or acquired).

Before keratoplasty, as well as before any other surgical procedure, the patient must undergo an examination. It will allow you to identify all indications and contraindications, identify risk factors, predict the results of the procedure.

Contraindications for keratoplasty:

• entropion (inversion of the eyelid, in which the edge of the eyelid and eyelashes come into contact with the cornea and conjuncture of the eye and irritate them);
• ectropion (in which the contact between the eyelid and the eyeball is broken, the mucous membrane of the eye is exposed);
• blepharitis (a group of diseases that provoke chronic inflammation of the eyelid);
• bacterial keratitis (an acute inflammatory process in the cornea, which is of a bacterial nature).

If these or other contraindications are found, a full treatment should be carried out, after which a second examination and operation (in the absence of diseases) should be done.

Prognosis for keratoplasty

With keratoplasty, you need to carefully analyze the possible outcome of the operation. Factors that can significantly worsen the result include the following phenomena:

• eyelid anomalies (ectopia, blepharitis, entropy,), which are best corrected before the procedure;
• tear film dysfunction (dry eye syndrome);
• relapse or progress of the inflammatory process in the conjunctiva (atrophic conjunctivitis, cicatricial pemphigoid);
• anterior synechia (a condition in which the iris sticks to the cornea or lens);
• pronounced vascularization of the stroma;
• active inflammation of the cornea;
• corneal insensitivity;
• severe thinning of the bed;
• uncompensated glaucoma;
• (inflammatory process in the choroid of the eye).

Keratoplasty with donor tissue

Corneal tissue sampling should be carried out within 24 hours from the moment of the donor's death. The corneas of newborns and infants are not used: they are too pliable, which increases the risk of developing high astigmatism. Donors older than 70 years are also not suitable, since at this age the cornea has a low density of endothelial cells.

Before the operation, the donor tissue is examined with a slit lamp. A more reliable method for examining the graft is mirror microscopy.

In what cases is the cornea unsuitable for transplantation:

• if the cause of death of the donor is unclear;
• if the donor had infectious diseases of the central nervous system (systemic sclerosing panencephalitis, Creutzfeldt-Jakob disease, multifocal leukoencephalopathy, etc.);
• if the donor had some systemic infections (syphilis, AIDS, septicemia, hepatitis);
• if the donor has leukemia, disseminated lymphoma;
• if the donor suffered from eye diseases (inflammatory process, malignant formations, history of surgery).

It is possible to use a prepared graft or take it directly from a donor eye. The doctor determines the size of the transplant in advance. You can determine the exact parameters in the light of a slit lamp. If the flap diameter reaches 8.5 mm, the risk of developing synechia, ocular hypertension, and vascularization increases. The best size is 7.5 mm. Smaller flaps are often complicated by astigmatism.

The size of the donor flap should exceed the affected area by 0.25 mm. This will ensure tightness, as well as weaken the flattening of the cornea after surgery. It also makes it possible to prevent the development of glaucoma.

Stages of keratoplasty

Keratoplasty is performed on an outpatient basis. First you need to choose anesthesia, which will depend on the state of health, concomitant diseases, the age of the patient and other things. Doctors use general and local anesthesia. A few hours after the operation, the patient is sent home.

Operation types:

1. Optical keratoplasty. The aim of the procedure is to improve visual function in cases of bullous keratopathy, dystrophy, scarring, degeneration or other damage to the cornea.
2. Plastic keratoplasty. It implies the preservation of the integrity of the cornea or its restoration. It is used for serious changes in the structure of the cornea (descemetocele, thinning of the stroma).
3. Therapeutic keratoplasty. The operation involves the replacement of infected tissue in case of failure of therapeutic treatment.
4. Cosmetic keratoplasty. The aim of the procedure is to improve the appearance of the eyeball in case of visible pathologies of the cornea.

How is keratoplasty performed?

1. Fixation of the eyeball.
2. Determining the size of the affected area to be removed.
3. Formation of a corneal flap according to pre-measured parameters.
4. Removal of affected tissues. The doctor can cut the flap manually, automatically or using a vacuum trephine. Removal of deformed tissues is carried out as carefully as possible. To protect the lens, pilocarpine miosis is created before keratoplasty, and viscoelastic is injected during the operation. After suturing, the viscoelastic is replaced with saline.
5. In order to avoid abrupt decompression, which can lead to prolapse of the membranes of the eye, an incomplete trepanation is performed and the anterior chamber is opened with a diamond knife.
6. Implantation of a graft, which should ideally fit the size of the removed flap.
7. Fixation of the graft with a special material for stitching. A thread thinner than a human hair is used. The graft is fixed with nylon 10/0 for the entire thickness of the cornea. First, the doctor applies four interrupted sutures, after which interrupted sutures, a circular continuous suture, or a combination of both are added.
8. After fixing with sutures, a tight pressure bandage is applied to the eye. In some cases, contact lenses are prescribed for additional protection.

Sometimes keratoplasty is performed using a femtosecond laser, which has a high speed of cutting the corneal flap. If indicated, keratoplasty may include reconstruction of the anterior segment of the eye through cataract removal, destruction of synechiae, iris plastic surgery, installation or reconstruction of intraocular lenses (artificial lenses).

Postoperative Therapy

The patient is given topical steroids to prevent rejection. Four doses per day are required for a couple of weeks, gradually the dose should be reduced depending on the condition of the eyeball. Most often, steroids should be used once a day for a year after surgery.

Also, after keratoplasty, signs of uveitis may occur, so it is worth using mydriatics twice a day for two weeks after surgery. Another patient is prescribed acyclovir orally if there is a history of herpesvirus keratitis (to prevent relapse).

The sutures are removed only after the complete engraftment of the graft after 6-12 months. In elderly patients, this process takes much longer. After suture removal, patients with astigmatism require rigid contact lenses to improve visual acuity.

Rehabilitation after keratoplasty

After keratoplasty, the eye recovers to an acceptable state in 9-12 months. This is due to the structural features of the cornea. The sutures are removed only six months after the operation. To prevent complications (inflammatory process, transplant rejection), the patient must be prescribed antibacterial agents and glucocorticosteroids in eye drops for a period of more than 2 months. The whole year of rehabilitation after keratoplasty, you need to protect your eyes from mechanical stress, avoid heavy physical activity.

Complications after corneal transplant

Keratoplasty, like any other surgical operation, is associated with certain risks. The consequence of corneal transplantation can be bleeding, infection, suture failure, complications from anesthesia.

Corneal surgery rarely develops macular edema (the center of the retina where light is focused), astigmatism, and increased intraocular pressure. Most often, complications after keratoplasty are associated with graft rejection.

Early complications:

• slow epithelialization;
• irritation with sutures, as a result, capillary hypertrophy;
• reduction of the anterior chamber;
• prolapse of the iris;
• increased intraocular pressure;
• uveitis;
• infection.

Late complications:

• astigmatism;
• glaucoma;
• pathological process;
• divergence of wound boundaries;
• retrocorneal membrane;
• cystic macular edema.

Transplant failure

Early graft failure is characterized by opacity from the first day after keratoplasty. The process is caused by the development of endothelial dysfunction with defective donor endothelium or surgical trauma.

Late failure is characterized by an immune rejection reaction. It is diagnosed in half of the cases after keratoplasty. Often, symptoms of rejection appear in the first six months after surgery (in most patients with rejection in the first year).

Types of rejection:

1. Epithelial, when there is a linear asymptomatic opacification of the epithelium. In this case, there are many small subepithelial infiltrates that resemble the clinical picture of adenovirus keratitis. This condition is sometimes accompanied by iritis. Epithelial rejection can be stopped with steroids.
2. Endothelial, when endothelial cells are damaged, leading to disruption of their regeneration processes. The immune response can lead to chronic corneal edema. Symptoms of endothelial rejection are iritis and inflammation at the sites of contact between the graft and the stratum corneum. As a result, there are linear deposits of precipitates, swelling of the cornea develops. You can stop rejection with the help of intensive instillation, parabulbar injections of steroids. Perhaps the use of immunosuppressants (systemic).

Cost of keratoplasty

When choosing a clinic, you need to pay attention to those institutions in which penetrating keratoplasty is a priority. On average, the cost of a cornea transplant operation costs from 100,000 to 300,000 rubles per eye.

The service package includes:

• proven biomaterial that will be used to restore the cornea;
• postoperative care (eye drops, antibiotics, protective eye patches, etc.);
• involvement of an experienced surgeon;
• development of an individual operation plan for each patient;
• the use of only modern equipment that does not allow excessive stress on the patient's cardiovascular system;
• selection of anesthesia that is well tolerated by patients;
• discharge only after the control examination of the surgeon;
• postoperative examinations and consultations;
• urgent medical care in case of complications.

In 90% of cases, keratoplasty can achieve a significant improvement in visual function. Few patients develop complications, most of which can be easily managed with medication.

The cornea does not have its own blood vessels, which makes its transplantation easier than other similar surgical interventions. This type of surgery is called corneal keratoplasty, and its implementation is not always aimed at restoring vision.

With a significant number of diseases of the cornea that provoke non-healing ulcers on it, clouding and scarring, as well as injuries and burns, it becomes necessary to perform keratoplasty, in fact, it can have one of three goals:

• Restore the lost quality of vision. At the same time, visual acuity and its quality are not restored immediately after the operation, but after a while.
• Save the eye as an organ. In this case, we are not talking about improving visual acuity.
• Stop the progression of the disease. As a rule, we are talking about preserving the eye as an organ, but there is no way to restore lost vision.

Keratoplasty is actually transplantation of the cornea of ​​the eye from a dead donor to a recipient.

At the same time, a significant time (sometimes more than a year) may pass from the decision on the need for such a transplant to the operation itself. In the course of preparation, it is necessary not only to find a suitable material for transplantation, but also to conduct examinations of the diseased eye, identify diseases that need to be treated before the operation, and clarify all the nuances of keratoplasty.

Indications and contraindications for keratoplasty

Indications for corneal transplantation (keratoplasty) will be the following cases:

• The formation of scars, thorns, opacities after injuries.
• Irreversible changes in epithelial-endothelial dystrophy, diffuse edema, which are accompanied by severe pain.
• Presence of keratoconus.
• The appearance on the cornea of ​​ulcers provoked by any kind of infection (bacterial, viral, fungal).
• Dystrophic deviations in the structure of the cornea, as a rule, are hereditary.
• The presence of thermal or chemical burns.
• Scar formation.
• Complications after surgical interventions on the eye.

Keratoplasty is not performed under the following circumstances.

• Corneal transplant surgery is not indicated if there is a high probability of graft rejection.
• Do not perform surgery for vascularized cataracts (the presence of ingrown blood vessels).

Operation is contraindicated in case of formation of a thorn in glaucoma.

In large ophthalmological clinics, there are equipped corneal banks and there are also special waiting lists for patients.

Material sampling is carried out from a dead recipient within 24 hours after death. Donors cannot be those who died from unknown causes or infectious diseases of the brain, its membranes, HIV infection, blood diseases, elderly people over 70 years of age and infants.

After taking the material, the cornea is preserved for 5-7 days in a special solution. During this time, it is tested for suitability as a transplant.

The resulting material is suitable for both penetrating keratoplasty and layer-by-layer keratoplasty, as well as for surgical intervention on the sclera and other parts of the eye.

Preparation for corneal keratoplasty

After the decision on the expediency of corneal transplantation is made, preparations for the transfer are carried out. The preparatory stage is very important during the operation of keratoplasty. It will include, in addition to the selection of a donor transplant, a number of additional activities.

• Examination by an ophthalmologist to identify diseases that prevent the operation.
• Treatment of identified pathologies.
• Making a decision on the possibility of keratoplasty after therapy.

The fact is that a number of diseases can significantly affect the engraftment of donor material after the operation, and even a perfectly performed operation will not give a positive result if the implant is rejected.

So, the cause of rejection of the engrafted cornea after keratoplasty can be high intraocular pressure or even the presence of unnoticed glaucoma, a number of other pathologies.

They need to be treated before surgery.

Types of surgery

There are several ways to carry out such operations. Most of them are performed under general anesthesia with a femtolaser knife, and all of them require a long period of rehabilitation.

The classification according to the volume of transplanted material is as follows.

• Total transplantation, which is carried out if it is necessary to replace all layers of the cornea in an area with a diameter greater than 9.5 mm and up to 12 mm. Sometimes (with severe burns) in such cases, the cornea is transplanted partially with the sclera.
• Subtotal keratoplasty, it is prescribed if it is necessary to replace an area with a diameter of more than 6.5 mm.
• Local keratoplasty or partial keratoplasty is done when the diameter of the transplanted sclera is not more than 4-6.5 mm.

With respect to the layers to be replaced, the following classification is used.

Penetrating keratoplasty

In this type of surgery, all layers of the cornea are replaced. It is indicated in the presence of clouding of a large area of ​​the cornea (keratoconus, burns, dystrophy).

During keratoplasty, all layers are excised with a special round knife (trephine) and a graft is placed in their place. This is the most frequently performed operation, today the use of a laser for its implementation is gaining great popularity. A special femtosecond laser makes a very precise cut, its edges are perfectly smooth, and the sutures are thin. This improves the process of engraftment of the material and shortens the rehabilitation period after transfer.

With end-to-end corneal replacements, other surgical interventions can also be performed: cataract removal and replacement of the lens with an IOL, excision of scars and adhesions in the anterior chamber, anterior vitrectomy.

End-to-end corneal replacement results in implant rejection in 10-30% of cases.

Layered keratoplasty

This method allows you to replace not all layers, but only a part, which significantly increases the chances of engraftment of donor material (almost 100%). At the same time, it is possible to maintain the transparency of the cornea and avoid astigmatism.

There are several types of this keratoplasty.

• With the anterior layered - the outer layers are replaced by the depth of their defeat.
• In posterior layered keratoplasty, inner layers require replacement.

These are complex operations, as they require excision of the affected area of ​​the recipient, as well as layering of the donor cornea into layers. In this case, the replaced flaps can be of various sizes and located in any part of the eye.

There are also types of movements according to their purpose.

So, when performing keratoplasty for therapeutic purposes, the question of restoring vision and transparency of the cornea is not worth it, it is important to excise the tissues affected by injury, illness or burn, and only then, after the process has faded, a second operation is performed - optical keratoplasty. With this operation, the goal is just to improve the optical environment: the creation of a transparent cornea. However, it is not uncommon that after the first transfer, the graft takes root well, vision improves, and a second transplant is not required.

During cosmetic transplantation, the operation is performed on blind eyes, and there is no question of returning vision, here it is a cosmetic procedure.

Refractive keratoplasty is performed on healthy eyes, its goal is to improve visual acuity. These operations are done under local anesthesia.

Recovery period after surgery

The duration of rehabilitation largely depends on the complexity of the operation and the size of the graft. So, after penetrating keratoplasty, the period of stay in the hospital will last 12 days, and with refractive transplants it can take 3-4 hours.

The entire rehabilitation period takes about a year. In the early days, you should observe a certain position of the head during sleep.

In the first weeks after the operation, the patient should not lift weights, exercise, it is recommended to wear glasses, protect the eyes from dust and injuries. A course of steroid therapy is usually prescribed (to improve implant engraftment).

The sutures are removed 6-12 months after the operation.

At first, vision after keratoplasty (when moving with an optical purpose) deteriorates, blurry objects are observed due to slight swelling of the implant, then it gradually improves, the final restoration of vision occurs after the removal of sutures (it is not necessary to rush with this so as not to provoke astigmatism). Over time, the quality of vision improves (if such a goal was set) in 70-80% of cases.

Possible Complications of Keratoplasty

Among the possible complications, there are early complications (observed up to 6 months after surgery), bleeding, allergic reactions, infections of the operated eye, suture failure.

Among the late ones, sometimes occurring after a few years - transplant rejection, high intraocular pressure, astigmatism.

Many experts argue that successful engraftment of a transplanted graft requires several components: well-performed preoperative preparation, high qualification of ophthalmic surgeons performing the operation, and high-quality modern equipment, as well as compliance with all doctor's prescriptions in the postoperative period. In addition, the quality of engraftment largely depends on the condition of the diseased eye and the general condition of the patient's immune system.

Are there complications after corneal transplantation?

As with any surgical intervention, undesirable effects are possible during keratoplasty. There are risks associated with anesthesia, infection, rupture of sutures, bleeding. Postoperative complications are associated with rejection of donor tissues. In some cases, the patient may develop astigmatism, intraocular pressure increases, macular edema of the retina appears.

What material is used to replace corneal tissues?

A unique donor material is used to replace damaged areas. The ophthalmic transplant has permits and certificates. The quality of products is confirmed by virological and biological tests. The risk of clouding and other complications is reduced, healthy material for corneal tissue repair takes root well and makes it possible to see perfectly.

What is the duration of the rehabilitation period?

After surgery and medical examination, the patient goes home. Within a year after keratoplasty, it is necessary to be observed by a specialist. Such a long period is associated with the specific structure of the cornea and the need to monitor the process of engraftment of donor tissues. The sutures are removed 6-12 months after transplantation. Immediately after eye surgery, it is necessary to stop lifting weights and other physical activities.

What methods of keratoplasty are used in Moscow?

Traditional methods of corneal transplantation are being improved. In Moscow, corneal discs are excised not with a metal trephine knife, but with a femtosecond laser. Thanks to this, the accuracy of the cut increases, donor tissues take root better, the postoperative period is shortened, and many complications are excluded.

What problems does corneal transplantation solve?

Surgical intervention solves the following tasks:

• Reconstruction of the eye, removal of deformed and damaged tissues, improvement of appearance.
• Absolute or partial relief from serious ailments. Donor tissue transplantation is performed for tumors, ulcers, cysts and corneal perforations. Damaged tissues are successfully restored after suffering keratitis, severe burns and in other cases.
• Restoring the transparency of the cornea improves visual acuity. The microsurgical operation eliminates the thorn in the eye, opacities of the corneal layers and other pathological processes. Visual acuity improves in 90% of patients.

Where is the best place to do keratoplasty?

Many high-class institutions have been opened in Moscow that work according to world standards and have the appropriate certificates and certificates. In the CELT clinic, ophthalmologists with successful experience in transplantation operate. The rehabilitation period is reduced to a minimum, thanks to the use of a femtosecond laser. Only high-quality material that has passed clinical trials is used as a transplant. An individual approach to each client is guaranteed, all wishes for the operation are taken into account.

When is layered keratoplasty indicated?

Anterior layered keratoplasty is a microsurgical operation during which only the upper corneal layers are excised. Compared to penetrating corneal transplantation, the structure of the anterior segment of the eye is not disturbed, the risk of rejection is excluded, and the patient has less astigmatism. These operations eliminate only superficial opacities of the stratum corneum. The main indications are superficial burns, initial dystrophic changes, etc. In all other cases, the method of end-to-end graft transplantation is indicated.

Keratoplasty- a surgical operation on the cornea, aimed at restoring its shape and functions, eliminating congenital and acquired after injuries and diseases defects and deformities. This operation consists in replacing sections of the cornea with a donor graft. It can be transplanted into the thickness of the cornea, located on the anterior layers of the cornea or replace them.

When is keratoplasty needed?

Corneal pathologies requiring keratoplasty include:

• keratoconus in advanced stages;
• various kinds of cataracts of the cornea - burn and dystrophic;
• congenital and acquired corneal dystrophy;
• corneal scars after injuries, operations and inflammations;
• traumatic corneal defects.

Keratoplasty is the replacement of the damaged area of ​​the cornea. The Excimer Ophthalmological Clinic uses Cornea Restoration Material as a replacement material. The unique material has passed clinical trials and has all the necessary registration documents and certificates from RosZdrav. "Material for the restoration of the cornea" is selected based on world standards, repeated studies are carried out not only biological and virological, but also studies of the endothelial layer of cells, which make it possible to make a prediction about its further viability and the results of a future operation. Unlike previously used materials, "Corneal Reconstruction Material" has better survival, much reduced risk of turbidity.

Tasks of keratoplasty

• Restoration or improvement of corneal transparency and improvement of visual acuity. It is carried out with various kinds of cataracts, primary dystrophies of the cornea, to replace cloudy layers of the cornea, with keratoconus.
• Stopping (full or partial) the progression of the disease, restoring the damaged cornea. It is carried out with fresh severe burns of the cornea, corneal ulcers, keratitis, tumors of the cornea, limbus, sclera, pterygium, deep corneal dystrophy, epithelial cysts of the anterior chamber of the eye, fistulas and perforations of the cornea and other conditions.
• Improvement of the appearance of the cornea and restoration(reconstruction) of its congenital or acquired after injuries and diseases defects and deformities.

• total, local, subtotal(according to the size of the corneal area to be replaced during keratoplasty);
• through, front layered, rear layered(according to the layers that are to be replaced in the process of keratoplasty).

How is keratoplasty performed at the Excimer clinic?

During the operation, the surgeon, using a microsurgical instrument or a femtosecond laser, forms a corneal flap and separates the damaged part of the cornea. In its place is implanted "Material for the restoration of the cornea", which exactly corresponds to the size of the previously formed flap. With the help of a specially suture material, it is attached to the peripheral part of the patient's cornea. After the operation is completed, a bandage or a special protective contact lens is applied to the patient's eye.

Keratoplasty in the Excimer clinic is performed in the mode "one day" under anesthesia or local anesthesia. After the operation and examination by the doctor, the patient returns home. The rehabilitation period after keratoplasty lasts up to a year in connection with the structural features of the cornea. During this period, the patient is regularly observed by the attending physician at the Excimer clinic, who monitors the dynamics of recovery. Removal of sutures usually occurs after 6 - 12 months after operation. After keratoplasty, it is recommended to avoid heavy physical exertion and physical impact on the operated eye.

Results of keratoplasty

In most cases, keratoplasty results in the best result. When treating keratoconus with keratoplasty, it is possible to stop the progression of the disease and achieve an improvement in optical characteristics.

Advantages of keratoplasty in the Excimer clinic

• The equipment, instruments and consumables used in the Excimer clinic meet all international standards, have passed rigorous clinical trials and have the necessary certificates and permits;
• Keratoplasty in the Excimer clinic is performed by highly qualified ophthalmic surgeons with unique experience in performing such operations;
• Postoperative complications and recovery period are minimized, the maximum result is achieved;
• The most sparing and effective technology for keratoplasty is available at the Excimer clinic - using a femtosecond laser;
• Doctors of the Excimer clinic have constant access to the bank of biomaterial, so the possibility of performing the operation depends only on the wishes of the patient and individual indications for keratoplasty.

Cost of basic services

The essence of the operation of anterior layered keratoplasty (DALK) is the implantation of a donor stroma while preserving the patient's Descemet's membrane with a layer of endothelial cells.

This technique significantly reduces the risk of transplant rejection, and yet, penetrating keratoplasty remains the most common procedure in our time. The explanation is simple: layered keratoplasty is more complex and time-consuming. At the same time, when performing anterior layered keratoplasty, the issue of irregularity of the corneal surface is acute. This can significantly reduce the optical result of the operation, in comparison with penetrating keratoplasty.

The progress of medical technology and the improvement of surgical instruments have become the key to improving the optical results of DALK. Thus, the rapid development of this technique has been greatly facilitated by modern microkeratomas and the use of femtosecond lasers.

Benefits of DALK

Today we can talk about the undeniable advantages of anterior layered keratoplasty over penetrating corneal transplantation. These include a significantly reduced risk of postoperative complications - the occurrence of cataracts, the development of glaucoma and retinal detachment, endophthalmitis, cystoid macular edema and expulsive hemorrhage. In addition, the ability to leave the endothelial layer intact reduces the risk of graft rejection. In addition, DALK does not compromise the integrity of the Descemet's membrane, and the corneal, tighter suture reduces the risk of postoperative astigmatism due to suturing.

Anterior layered keratoplasty: technique

The course of the operation of the anterior layered keratoplasty consists in the manual dissection of the layers of the corneal stroma. Usually, the separation of layers in this way is easy, with an accurate result. True, visual acuity after such separation remains insufficiently high, since an irregular interface and scarring are possible. In this regard, a somewhat improved technique for separating the stromal corneal layers was developed. This technique allows the surgeon to penetrate deeper corneal layers consistently and most safely. This technique is called deep anterior laminar keratoplasty (DALK). When using it, the layers are sequentially separated manually, air, silicone and ophthalmic viscoelastics are introduced. At the same time, the histological studies carried out make us think about the guarantees of a layer-by-layer smooth separation of the stroma in the region of the Descemet's membrane.

According to recent studies, the results after DALK and traditional deep anterior lamellar keratoplasty are almost the same. But endothelial cell loss is somewhat lower in DALK. A significant advantage of this technique was also the easy exposure and separation of the Descemet's membrane, which guarantees less damage during transplantation. At the same time, the reoperation takes place with an easier separation of the existing graft and its replacement with a new one. And yet, there is difficulty in assessing the depth of the incision using an operating microscope, so even the most experienced surgeons allow up to 39% of cases of perforation.

Safe access to the Descemet's membrane is essential to improve the results of deep transplantation. The main advantage of the operation of deep layered keratoplasty in this case is the elimination of the negative impact of the donor stroma interface and the occurrence of astigmatism and scarring associated with this. Thanks to this, a faster rehabilitation of the visual function occurs. The main task of the surgeon when performing an operation using this technique is to reach the Descemet's membrane and separate the inner stromal layers without perforating the Descemet's membrane.

Keratoplasty and femtosecond laser

Corneal transplant operations are currently characterized by a fairly high "survival" of the graft. And yet, the greatest difficulty for the complete rehabilitation of patients remains postoperative astigmatism.

Presumably, the "culprits" of optical distortions are a number of factors. These include: junction between the graft and the patient's corneal tissue, rotational mismatch, overtight or uneven suture, slow or rough postoperative healing. It should be noted that when trepanning the cornea, both the donor and the patient, as a rule, a manual disposable trephine and vacuum are used. Such a procedure "sins" by creating different angles with unequal cuts. At the same time, unequally cut edges after stitching create "barrel-shaped" connections, which are poorly controlled during the operation under a microscope.

Back in 1950, Barraquer substantiated the healing advantages of penetrating keratoplasty with stepped incisions. Later, using the example of a significant decrease in postoperative astigmatism, this was confirmed by Basin. The formation of a stepped incision made it possible to transplant a larger area while maintaining the integrity of endothelial cells. It also helped to remotely secure the limbus from the anterior edge of the graft, which contributed to the fastest healing. Performing an incision of this configuration by hand is difficult and unpredictable for the surgeon, and every millimeter of unevenness can lead to the formation of an inadequate edge. This can lead to a deterioration in the optical transparency of the graft and hinder the healing process.

However, a femtosecond laser can easily cope with this task. It is able to form the required configuration of the incision with multiple laser pulses applied through the corneal tissue. As shown by laboratory studies and practical results obtained, the use of femtosecond lasers gives a 7-fold greater resistance of the seam to pressure and significantly less astigmatism. In addition, the femtosecond incision allows better alignment of the graft connection with the patient's cornea, an increase in the area of ​​the connection due to the zigzag shape of the edges, and an optimization of the tension force of the incision during the healing process. The results of optical coherence tomography prove the exact correspondence of the edges with such an incision and their excellent healing in the postoperative period. The femtosecond technique shows an average astigmatism after surgery of approximately 3.0D after a month and after nine months of follow-up.

In individuals with corneal ectasia, the use of a femtosecond laser helps to preserve both the Descemet's membrane and the endothelial layer unchanged, even when replacing almost the entire stroma. Significantly greater advantages can be obtained by combining a femtosecond cut and air separation of the corneal layers.

True, it should be noted that during corneal transplantation, a femtosecond laser does not allow the formation of an absolutely ideal surface, as when making a valve in the process of laser correction. Perhaps this is due to an increase in the stromal layers, the process of scarring and disruption of the shape of collagen fibers in corneal anomalies or the need for an incision in its deeper layers.

With a femtosecond laser, an unlimited number of cut configurations can theoretically be programmed and formed, whose optimal shape has yet to be studied.

It is also necessary to study aspects of the diode connection between the edges of the incisions with the use of special adhesives, possibly capable of minimizing the adverse effects of sutures in the formation of postoperative astigmatism.