Справочная служба МНТК (г. Москва): +7 (499) 906-50-01
МНТК в соц сетях:

Пациентам

Corneal diseases

Corneal diseases develop in 25% patients who seek ophthalmologic care. Cornea is a transparent eye shell of 10-12 mm in diameter, which, like a watch glass, covers the colored structure of the eye, called the iris.

Reducing the transparency of the cornea, resulting in loss of vision, can be triggered by many causes: eye burns and injuries, keratitis and corneal ulcers, primary and secondary corneal dystrophy, keratoconus and keratoglobus. Such corneal injuries and diseases required surgical treatment.

TREATMENT

The surgical treatment of corneal diseases has two main directions: keratoplasty (corneal transplantation), when the damaged cornea is replaced by a healthy donor corneal tissue, and keratoprosthesis, i.e. implantation of the artificial cornea.

The Eye Microsurgery CSTC has the most extensive experience in Russia in the sphere of corneal transplantation: for 30 years we have made over 16,500 donor corneal transplantations. The Eye Microsurgery CSTC has the largest modern Eye Bank in Russia with cutting-edge medical and technical equipment. The Center is the only Russian medical facility which intensively uses the method of keratoprosthesis with its own models of keratoprostheses.

Keratoplasty is indicated to patients with keratoconus, corneal dystrophy, corneal opacities, etc.

Keratoplasty The total time required for treating one eye is 14-21 days (preoperative examination – 2-3 days, surgery – on the 4th day (the time of surgery depends on the availability of donor materials), postoperative aftercare – 10 days)

Keratoprosthesis is performed to treat leucoma.

Keratoprosthesis The total time required for treating one eye (one stage) is 5 days (1st stage – leukoma reinforcement and implantation of support elements, preoperative examination – 2 days, surgery – on the 2nd or 3rd day, postoperative follow up – 1-2 days; 2nd stage of keratoprosthesis implantation (3-4 months after the 1st stage). The term of surgery is similar to stage I.

Keratoplasty and keratoprosthesis procedures are performed in-patiently and usually take 30 to 60 minutes. In the surgical room, you will be attended by a surgeon, his/her assistant, an operating room nurse, an anesthesiologist and a nurse anesthetist. The modern anesthetic methods used by the Eye Microsurgery CSTC make the procedure absolutely painless. Surgeries are carried out by highly qualified surgeons of the department of transplantation and optical reconstruction surgery of the anterior segment of the eyeball using cutting-edge equipment from the leading world producers.

Recently, the Eye Microsurgery CSTC has been actively using new techniques of the surgical treatment of corneal and keratoconus dystrophy at early stages of the disease.

  • The deep anterior stratified keratoplasty, which helps to retain a patient’s own healthy endothelium and avoid the incision of the eyeball (depressurization), reduce the risk of intra- and post-operative and complications and transplant rejection.
  • The posterior layered endothelial keratoplasty designed for the treatment of corneal dystrophy helps to minimize the portion of donor tissue, which reduces the risk of rejection and retains most of a patient’s own cornea.
  • Reconstruction of the anterior segment of the eyeball with artificial iris implantation using penetrating keratoplasty is performed in case of severe injuries of the cornea in combination with loss of the lens and iris.
  • Introstrimal keratoplasty with implantation of segments is an alternative to penetrating keratoplasty at early and advanced stages of keratoconus. The surgery is performed out at early stages of keratoconus, has an orthopedic function, strengthens the thinned area, improves visual acuity, stops the progression of keratoconus.
  • Corneal collagen cross-linking slows down or stops the progression of keratoconus by biochemical remodulation of the cornea.

The improvement of microsurgical equipment and tools, the development of new advanced devices, new approaches to pre- and postoperative therapies have expanded the range of surgical interventions on the cornea and led to high percentage of favorable outcomes and good results.

MODERN KERATOCONUS DIAGNOSIS AND TREATMENT METHODS

KERATOCONUS

Keratoconus is a progressive dystrophic disease of the cornea caused by a number of genetic and acquired factors, characterized by progressive thinning of the cornea with protrusion of its central parts, formation of myopic refraction and irregular astigmatism.

The etiology of keratoconus and other types of keratoectasia is currently unknown. Active keratoconus progression occurs in 20% of cases and, as a rule, begins in the pubertal period. Progression of the disease leads to a significant reduction in visual acuity and ineffectiveness of the methods of its correction.

The diagnosis is especially difficult in the initial stages of the disease. To date, the most informative examination in diagnosing this formidable disease, along with the generally accepted examination methods, is performed using the PENTACAM (OCULUS, Germany) scanning keratotopograph, which allows estimating both the anterior and, which is the most important, posterior surface of the cornea - since this is where initial changes in the anatomical and topographical characteristics occur at the initial stages (Figure 1).

Treatment of keratoconus

Depending on the stage of the disease and some important anatomical and topographic characteristics, the ophthalmic surgeon, based on many years of experience and the latest scientific developments of the Eye Microsurgery CSTC will offer the optimal method of treatment. There are three methods of treatment of keratoconus:

1. Corneal collagen cross-linking (Fig. 2)

The idea of using a conservative method for the treatment of keratoconus appeared in Germany in a group of researchers at the Dresden Technical University. T. Seiler and G. Wollensak took as a basis the principle of photopolymerization, which has long been used in dentistry ("light seal"). As a result of a series of works, the most effective and safe technique for corneal collagen cross-linking based on the effect of photopolymerization of stromal fibers under the action of a photomediator (riboflavin solution) and low doses of ultraviolet radiation of a solid source was developed. This technique helps to stop the progression of keratoconus and to avoid penetrating transplantation of the cornea.

Indications:

  • Stage I-II keratoconus.
  • Keratoectasia after refractive excimer laser interventions.
  • Marginal corneal degeneration
  • Keratomalations of different genesis – cornea melting, usually as part of autoimmune processes.
  • Keratoglobus.
  • Stage I-II bullous keratopathy.
  • There is encouraging evidence for the use of cross-linking in the treatment of keratitis and corneal ulcers.

Contraindications:

  • Riboflavin (vitamin B2) intolerance.
  • If the corneal thickness at least in one dimension is less than 400 microns.
  • Age under 15 years
  • Low corrected visual acuity in keratoconus, despite sufficient thickness.
  • Corneal scarring.
  • Allergic conjunctivitis.

2. Implantation of intrastromal corneal segments

In our practice, we use Russian intrastromal corneal segments (ICSs) made by Scientific and Experimental Production “Eye Microsurgery” LLC of polymethylmethacrylate, which are segments with an arc length of 160° (90, 120, 160, 210°), a base of 0.6 mm, a height of 150-450 μm, an internal diameter of 5.0 mm and an outer diameter of 6.2 mm, with a cross section in the form of a hemisphere (Fig. 3).

Correction of keratoconus and compound myopic astigmatism of a high degree. Previously, a corneal tunnel is formed in the cornea through which a corneal segment will be inserted, which results in flattening the central area of the cornea. A rather important aspect of the surgery is its reversibility, i.e. the possibility to replace or remove a segment if the vision changes with age. This is possible as the corneal center is not damaged and the corneal tissue is not removed. A patient's eye is absolutely calm the next day and after a short period of rehabilitation the patient can experience daily visual loads (Figure 4). It should be noted that implantation of the intrastromal segment does not affect the patient's cosmetics and allows using soft contact lenses. Depending on indications, cross-linking may be combined with implantation of intrastromal corneal segments.

3. Keratoplasty

Recently, deep anterior lamellar keratoplasty, a surgical procedure for removing the corneal stroma down to Descemet's membrane, often becomes the treatment of choice for advanced keratoectasia. An increase in visual acuity in this case is comparable with that after penetrating keratoplasty. Advantages of deep anterior lamellar keratoplasty compared with penetrating keratoplasty are as follows: preservation of the recipient's corneal endothelium, which reduces the risk of transplant rejection; reduction of the risk of cataract development in the postoperative period due to a shortened course of steroid therapy; reduced requirements for donor transplant, as the quality of its endothelium in this case does not play such a significant role as in penetrating keratoplasty.

It should be noted that the best results can be obtained by carrying out keratoplasty – both penetrating and deep anterior lamellar keratoplasty – using a femtosecond laser, which provides an ideal accuracy of the cut and an unrivaled alignment of the cut donor transplant and the recipient's bed, which leads to a significant increase in the visual function of the patient. Thus, currently in the arsenal of a qualified ophthalmic surgeon there is a wide range of surgical methods for treating keratoconus. However, it should be noted that treatment is considered the most effective at early stages of the keratectactic process, which is possible in case of timely and correct diagnosis of the keratectactic process.

The most effective modern methods of early diagnosis of the keratectatic process are: computer keratotopography, optical coherence tomography, confocal scanning microscopy, immersion confocal microscopy, analysis of corneal elevation maps.

Our institute is fitted with the most advanced equipment for early diagnosis of keratoconus, which allows the detection of this disease at its earliest stages in 100%.

It should also be noted that the abundance of various methods of treating keratoconus poses to an operating surgeon the task of selecting the most effective method of treatment for each particular patient.

The leading specialist of our institute, Ismaylova Svetlana Borisovna, MD, based on a comprehensive analysis of results of treatment of patients with keratoconus, has developed an algorithm for the surgical treatment of keratoconus to systematize approaches to the treatment of keratoconus and differentially choose the most optimal and effective method of treatment depending on the stage of the disease. Thus, the Eye Microsurgery CSTC has the whole range of modern medical diagnostic technologies to carry out pathogenetically oriented treatment for each patient with keratoconus at any stage - from the initial to the acute ones. We can help each patient!