RU2620757C1 - Method for keratoconus treatment - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: cornea is dissected at a depth of 110-120 microns, depending on the original thickness of the cornea. The flap is removed to the side and a riboflavin solution installed thereon, laser correction is performed by the LASIK method, then the riboflavin solution is immediately installed on the altered cornea, then the flap is placed in its original place, then activated by a UV laser with a wavelength of 370 nm and radiation power of 7 mV/cm² for 15 minutes.

EFFECT: method allows to increase visual acuity by 2-3 lines without correction, with a maximum correction of 3-4 lines, and reduces the cross-linking time to 15 minutes, which causes reduced loss of keratocytes.

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Description

The invention relates to medicine, namely to ophthalmology, and can be used in the treatment of progressive keratoconus at stages 1 and 2.

Keratoconus is a non-inflammatory, often bilateral, dystrophic disease of the cornea, characterized by progressive asymmetric thinning of the cornea with a protrusion of its central sections, decreased visual acuity, leading to disability of patients at a young working age. The etiology and pathogenesis of keratoconus is not well understood. This disease can be primary, genetically determined, or secondary, which is one of the most serious complications of refractive surgery.

Analogs

A known method of laser surgery of early keratoconus, comprising a combination of photorefractive keratectomy (PRK) and phototherapeutic keratectomy (FTK). For surgery, an EC-5000 excimer laser from NIDEK is used. The diameter of the PRK is 6.0 mm. FTK is carried out with an ablation zone of 8.00. The FTK ablation zone is shifted in the direction of the site of greatest ectasia — the vertex of the cone; the topography and localization of the vertex are previously determined using computer topography (E. A. Kasparova. Diagnosis and treatment of early keratoconus. 2001). However, with this method, a positive result can be achieved only with the initial and non-progressive form of keratoconus. The disadvantages of the operation are also: a long period of postoperative discomfort (lacrimation, photophobia, a splinter feeling in the eye) and the possibility of forming a slight opacification on the cornea (about 1: 500 happens).

A known method of treating keratoconus by implanting introstromal corneal segments of Ferrara. Implantation is carried out in a 5-mm zone at a depth of 2/3 of the cornea thickness, focusing on the localization of the apex of the keratoconus and the boundary line of corneal deformation (Dvoli M.P., Tsiptsadze I.A., Sibriladze B.V., Gibradze K. Fedorov readings, 2004. New technologies in the treatment of corneal diseases. Scientific-practical conference, p. 11). The disadvantage of this method is the long-lasting edema of the cornea, the development of corneal astigmatism, unstable stabilization of keratoconus.

In recent years, to stabilize the pathological process with keratoconus, a method for treating corneal collagen crosslinking has been proposed - an effective minimally invasive method used in ophthalmology, mainly to stop the progression of keratoconus, as well as for the treatment of some other diseases (for example, corneal dystrophy). The technique was developed by a group of scientists led by Theodor Zeiler in the late 90s of the last century, but has gained wide practical application since about 2004. The methodology is based on the ability of collagen fibers of the cornea to change the structure under the influence of physical or chemical factors (heat, radiation, enzymes). In the process of crosslinking, the cornea of the eye in the presence of vitamin B2 (which is a photosensitive substance) is exposed to low-intensity ultraviolet radiation. Under the influence of rays, the decomposition of riboflavin molecules occurs, accompanied by the formation of a large number of free oxygen radicals. When released, oxygen molecules cause the polymerization of collagen fibrils and stimulate their "bonding" between themselves. Thus, previously collagenized fibers form a stronger structure. The result of performing corneal crosslinking is to increase the strength properties of the cornea, increase its resistance to stretching and stop the progression of keratoconus (Wollensak G., Spoerl E., Seiler T. Stress - strain measurements of human and porcine corneas after riboflavin Ultravoilet-A-induced collagen cross- linking // J Cataract Refract Surg. - 2003. - Vol. 29. - P. - 1780-1785). However, in some patients, this procedure is not possible, for example, with insufficient thickness of the cornea (traditional cross-linking is possible with a corneal thickness of more than 400 microns). In addition, the method does not guarantee an increase in visual acuity, although in 25% of cases, visual acuity increases by 1-2 lines due to flattening of the cornea, and, accordingly, a decrease in astigmatism.

Prototype of the invention

Closest to the claimed method is a method of treating keratoconus, which consists in the following (patent RU 2466699, publ. 20.11.2012). Using a femtosecond laser, two arched corneal incisions are made with the formation of an intrastromal “pocket” in the cornea with the following topographic parameters: section depth 120-140 μm, depending on the initial thickness of the cornea, diameter 9.0, the location of the corneal sections 90 ° symmetrical and 270 °. After that, a syringe with a cannula is introduced into the formed "pockets" of 0.1% riboflavin solution, wait 15-20 minutes to soak the corneal stroma with a photosensitizer, and the cornea is irradiated with ultraviolet light with a wavelength of 365-375 nm for 30 minutes. However, the use of such stromal pockets is not recommended, since keratoconus weakens the already weak biomechanical stability of the cornea. In addition, as with standard crosslinking, the method does not guarantee an increase in visual acuity and a decrease in astigmatism. This method is taken as a prototype.

The purpose of the invention

The aim of the invention is to increase the effectiveness of treatment, reduce the frequency of postoperative complications, ensure a steady increase in visual acuity, reduce the risk of side effects and reduce the time of rehabilitation of patients.

SUMMARY OF THE INVENTION

The proposed method is as follows: under local drip anesthesia with alkaine, a surface corneal flap is formed using a microkeratome or a femtosecond laser, which makes a corneal incision at a depth of 110-120 microns, depending on the initial thickness of the cornea. After that, the flap is laid aside, laser correction is performed by the standard LASIK method, then a 0.1% riboflavin solution is installed and wait 15-20 minutes until the front chamber is completely stained with yellow pigment. Excess riboflavin is removed with sterile saline. The formed corneal flap is periodically moistened with a solution of riboflavin to prevent overdrying and laid in its original place. Then, it is activated for 15 minutes by an ultraviolet laser from a distance of 1 cm (or more, depending on the focal point of the UVA source) with a wavelength of 370 nm and a radiation power of 7 mV / cm2. During irradiation, an instillation of riboflavin solution is used every 3 minutes. In the postoperative period, antibacterial, anti-inflammatory drops and root protectors are used. The method has several advantages: in contrast to the claimed prototype, the method allows to increase visual acuity without correction by 2-3 lines, with maximum correction by 3-4 lines, and also allows to reduce the cross-linking time to 15 minutes, since high power is used (7 mV / cm2). The short exposure time of UV radiation causes less keratocyte loss, since fibroblasts are resistant to radiation of greater power for a short time. This fact provides high-quality and safe corneal crosslinking. In contrast to the standard cross-linking technique, corneal epithelium remains viable in this method (80%) and the baumen membrane is not damaged, which contributes to the quick recovery of vision, the absence of pain and the reduction of the risk of infections. In addition, this method ensures fast delivery of the photosensitizer to the cornea, which also reduces the time of surgery. All this increases the effectiveness of treatment, reduces the frequency of postoperative complications, provides a steady increase in visual acuity, reduces the risk of side effects and shortens the rehabilitation of patients.

An example of a specific implementation of the method

Example 1. Patient R., 25 years old, sought advice from GBU RD NPO "Dagestan Center for Eye Microsurgery" of the city of Kaspiysk with complaints of decreased vision. From the anamnesis it was found that visual impairment occurred about 2 years. Spectacle correction was not performed. A complete ophthalmological examination was performed. Diagnosis: Keratoconus 2 degrees of the right eye, 1 degree of the left eye. Diagnostic data before surgery: Visual acuity: right eye 0.5 n / a, left eye 0.6 s corr. Sph -0.5 cyl -0.75 ah 120 = 0.7. Refractometry: right eye Sph -1.25 cyl -1.50 ah 90, left eye Sph -1.0 cyl -0.75 ah 124. Pachymetry: right eye, center 427 μm, left eye 470 μm. The patient was treated with kerataconus according to the claimed method. The technique was carried out as follows. Local anesthesia with alkaine of the operated eye is performed (in the particular case, the right eye was operated on) 10 minutes before the operation and immediately before the operation. An epithelial flap is formed using a NIDEK microkeratome MK 2000 (Japan) with the possibility of a horizontal cut (cut depth 110-120 μm). The microkeratome set includes: a fixing vacuum ring, a mini-electric motor, which provides translational movement of the keratome and cutting movement of the blade with a frequency of 6000 rpm, a set of interchangeable heads or fixed boards for conducting slices of various depths. Microkeratum is equipped with disposable interchangeable blades that are inserted into the head immediately before surgery. The vacuum portion of the microkeratome was placed on the eye concentrically to the pupil. The vacuum created a pressure in the range of 0.8 atmospheres, and the IOP in this case increased to 60-65 mm Hg. (L.I. Balashevich, 2002). Microkeratome was delivered automatically. The movement of the blade is straightforward to the limiter, and then when you press the second pedal - the opposite along the same path. After the formation of the flap was completed, the vacuum was turned off and removed with a microkeratome. Using a thin flat spatula, the corneal flap was separated from the stroma and folded to the nasal side. Calibration was performed before each procedure. In accordance with the developed nomograms, the refractive parameters were entered into a laser computer, after which the laser affected the stroma. Keratoablation was carried out using the NIDEK excimer laser system “EC-5000” (Japan) - it is an argon-fluoride laser with a wavelength of 193 nm, with a rotational scanning beam feed mechanism with different energies (100-140 μJ / cm) with a frequency of 10 to 50 Hz. Postoperative refraction corresponded to emmetropia in all cases. After ablation of the corneal stroma, 0.1% riboflavin solution was instilled and waited 15-20 minutes until riboflavin was completely stained with moisture in the anterior chamber. In parallel, the epithelial flap was wetted with a solution of riboflavin to prevent overdrying. Next, the flap was placed in its original place and the crosslinking procedure was carried out using the Ufalk device; the beam of the device focuses on the top of the cornea. UV irradiation is carried out for 15 minutes with a periodic instillation of riboflavin 0.1% every 3 minutes. The radiation power is 7 mW / cm2. After the operation, the operated eye was washed with saline, antibiotics, root protectors, anti-inflammatory drugs were installed for 14 days. A contact lens was put on for 3 days after surgery. The sharpness of the right eye the day after removing the soft contact lens of 0.6 n / a. The patient indicated a slight blurred vision. From 2 days after the operation, a decrease in blurred vision was noted. From the 5th day after the procedure, the patient began to notice an improvement in visual acuity. After discharge from the hospital, the patient was invited for follow-up examination 1, 3, 6, 12, 18, 24 months after the operation. The minimum postoperative follow-up for the patient was 2 years. 3 months after the operation, the visual acuity of the right eye without correction of 0.9 with a maximum correction of 1.0 and remained stable for 2 years.

Example 2. Patient V., 23 years old, sought advice from the Dagestan Eye Microsurgery Center in Kaspiysk with complaints of decreased vision in her left eye. From the anamnesis it was found that visual impairment occurred about 2 years. Spectacle correction was not performed. A complete ophthalmological examination was performed. Diagnosis: Keratoconus 2 degrees of the left eye. Diagnostic data before surgery: Visual acuity: right eye 1.0 left eye 0.6 n / a. Refractometry: right eye Sph -0.25 cyl -0.0 ax 0, left eye Sph -1.5 cyl -1.5 ax 140. Pachymetry: Right eye, center 568 μm, left eye 488 μm. The patient underwent treatment of keratoconus of the left eye with the claimed method in the same manner as in Example 1. Visual acuity of the left eye on the day after surgery 0.7. From the 5th day after the procedure, the patient began to notice an improvement in vision. 3 months after the operation, the result was persistent and the visual acuity of the left eye was 1.0. Using the proposed method can significantly increase visual acuity and achieve stabilization of the result.

Features of the invention, distinctive from the prototype

1. According to the proposed method, a surface corneal flap is formed using a microkeratome or a femtosecond laser, simultaneous corneal crosslinking is performed in combination with laser correction using the LASIK method.

2. A section of the cornea is carried out at a depth of 110-120 microns, depending on the initial thickness of the cornea, after which the flap is set aside, laser correction is performed using the standard LASIK method.

3. Then immediately instill a 0.1% solution of riboflavin and wait 15-20 minutes until the moisture in the anterior chamber is completely stained with yellow pigment. Next, the flap is placed in its original place. Then, it is activated for 15 minutes by an ultraviolet laser from a distance of 1 cm (or more, depending on the focal point of the UVA source) with a wavelength of 370 nm and a radiation power of 7 mV / cm2.

4. According to the prototype method using a femtosecond laser, two arcuate corneal incisions are performed with the formation of an intrastromal “pocket” in the cornea at a depth of 120-140 μm. After this, a syringe with a cannula is introduced into the formed "pockets" of 0.1% riboflavin solution, wait 15-20 minutes to soak the stroma of the cornea with a photosensitizer, and the cornea is irradiated with ultraviolet light with a wavelength of 365-375 nm for 30 minutes. However, the use of such stromal pockets is not recommended, since keratoconus weakens the already weak biomechanical stability of the cornea. In addition, this method does not guarantee an increase in visual acuity and a decrease in astigmatism.

The positive effect of the application of the proposed method of treatment.

The positive effect of the application of the invention is that the instant treatment of keratoconus provides:

- persistent improvement in visual acuity and stabilization of the process;

- reduction of operation time;

- reducing the risk of postoperative complications;

- a more comfortable postoperative period;

- A short period of unpleasant postoperative manifestations (4-5 hours);

- fast recovery of vision;

- there is no risk of clouding of the cornea.

The method allows to increase visual acuity to 1.0, and also allows to reduce the cross-linking time to 15 minutes, since a large power is used (7 mV / cm2). This fact provides high-quality and safe corneal crosslinking. The proposed method is distinguished by the simultaneity and pathogenetic orientation of therapy, contributing to an increase in the effectiveness of functional rehabilitation of patients.

The proposed method includes laser correction using the standard LASIK method and ultraviolet corneal crosslinking with a 0.1% riboflavin solution, the formation of a surface corneal flap using a microkeratome or a femtosecond laser, which makes a corneal incision at a depth of 110-120 microns depending on the initial thickness of the cornea. After the flap is formed, laser correction is performed using the standard LASIK method, followed by instillation of a 0.1% solution and riboflavin and activating it with an ultraviolet laser from a distance of 1 cm (or more depending on the focus point of the UVA source) with a wavelength of 370 nm, which is different in that it is used radiation power of 7 mV / cm2 for 15 minutes, since a short exposure time to UV radiation causes less loss of keratocytes, since fibroblasts are resistant to radiation of greater power for a short time. This fact provides high-quality and safe corneal crosslinking.

Information sources

Patent RU 2466699, publ. 11/20/2012 - a prototype.

Dvoli M.P., Tsiptsadze I.A., Sibriladze B.V., Gibradze K. Fedorov readings, 2004. New technologies in the treatment of corneal diseases. Scientific and Practical Conference, p. eleven.

E.A. Kasparova. Diagnosis and treatment of early keratoconus. 2001).

Wollensak G., Spoerl E., Seiler T. Stress - strain measurements of human and porcine corneas after riboflavin Ultravoilet-A-induced collagen cross-linking // J Cataract Refract Surg. - 2003. - Vol. 29. - P. - 1780-1785.

Claims (1)

A method of treating keratoconus of the cornea, comprising injecting a solution of riboflavin into the cornea and irradiating the cornea with an ultraviolet light, characterized in that a surface flap of the cornea is formed, the cornea is cut at a depth of 110-120 microns, depending on the initial thickness of the cornea, after which the flap is moved to the side and a riboflavin solution is installed on it, then laser correction is performed using the LASIK method, then a riboflavin solution is immediately installed on the changed cornea, then the flap is placed on its original m Of course, then they activate it for 15 minutes with an ultraviolet laser with a wavelength of 370 nm and a radiation power of 7 mV / cm ² .