RU2769068C1 - Method for restoring the epithelial layer of the cornea in unilateral limbal insufficiency syndrome using a low-energy femtosecond laser - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to ophthalmology, and can be used to treat patients with unilateral limbal insufficiency syndrome (LIS), with complete or partial corneal conjunctivalization due to various eye diseases. To do this, superficial excision of fibrovascular tissue is performed on the surface of the cornea with LIS. Then the vacuum ring is fixed on the surface of the eye. A femtosecond laser head is attached to it. After that, the cornea is scanned using the optical coherence tomography laser built into the handle, the location, depth and configuration of the incisions are specified. When forming each tunnel with a laser, first a cut is made perpendicular to the leveled surface of the cornea, and then an oblique cut. The laser is then activated and tangentially or radially arranged corneal tunnels are performed. The length of the tunnel is 1.0 mm, the width is 0.5 mm, the total number of tunnels is 8-10. The tunnel depth is 200-330 mcm. Next, the vacuum is deactivated and the laser head with the vacuum ring is smoothly disconnected from the cornea. A rectangular limbal flap 1-1.5 mm wide and 2.0-2.5 mm long is cut out from the recipient eye and divided into 8-10 fragments. One limb fragment is placed in each of the formed tunnels. An amniotic membrane is applied to the surface of the cornea and fixed. Install a soft contact lens on the amniotic membrane for a period of 2 weeks.

EFFECT: invention provides re-epithelialization of the cornea in a short time due to dosed operation of the laser at the stage of microtunnel formation and intraoperative optical coherence tomography, which in turn minimizes intraoperative risks and facilitates the postoperative period.

2 cl, 3 dwg, 3 ex

Description

The invention relates to medicine, and more specifically to ophthalmology, and can be used in the treatment of patients with unilateral limbal insufficiency syndrome (SLN), namely with complete or partial corneal conjunctivalization due to various eye diseases.

SLN develops when the population of limbal epithelial stem cells (LESCs), which are responsible for the renewal cycle of the corneal epithelial layer, dies. The causes of this pathological condition are injuries and burns of the eyes, autoimmune and inflammatory diseases of the ocular surface. As a result of the absence of a natural barrier between the cornea and the conjunctiva, the corneal epithelium is replaced by fibrovascular tissue of conjunctival origin. SLE is accompanied by ingrowth of newly formed vessels and the formation of a fibrovascular pannus. These changes lead to a significant decrease in visual acuity, lacrimation, photophobia, chronic dry eye syndrome and, subsequently, to pain due to recurrent corneal erosions. The described clinical picture significantly reduces the patient's quality of life.

The closest analogue of the proposed invention is a method for restoring the epithelial layer of the cornea in case of unilateral SLE, in which the fibrovascular pannus is excised from the surface of the cornea of the affected eye, a limbal flap is cut out on the paired contralateral eye in the upper sector, its fragments are transplanted onto the operated eye, and a protective coating is applied. After excision of the fibrovascular pannus in the eye with SLN, 8 superficial symmetrical radial incisions are made in the region of the periphery of the corneal stroma to a depth of about 50 μm. Next, a stratifier forms an oblique or horizontal tunnel 1 mm long from each incision, divides the cut limbal flap into 8 fragments, each of which is placed in a separate tunnel. Further, as a protective coating, an amniotic membrane is applied to the entire surface of the cornea and fixed with sutures outside the limbus. In the case of complete SLN, before removing the fibrovascular pannus, a 360-degree peritomy behind the limbus is performed (RF Patent for Invention No. 2741411).

The disadvantage of this method is the risk of corneal perforation at the stage of tunneling, since this method does not allow control of the depth of the incisions and, therefore, does not give the surgeon full confidence in performing this surgical procedure. Also, the pathologically altered cornea can have a different thickness in different areas, which contributes to its perforation during the formation of the tunnel.

The objective of this invention is to develop an efficient, safe and predictable method for the restoration of the corneal surface by forming microtunnels using a low-energy femtosecond laser.

The resulting technical result consists in reducing the number of intraoperative complications due to the provision of dosed laser work at the stage of microtunnel formation and intraoperative optical coherence tomography (OCT).

The technical result is achieved by the fact that before the operation, retrobulbar anesthesia of the eye is performed, then the surgical field of the recipient eye is treated with a 5% solution of povidone-iodine. In the eye with SLN, superficial excision of fibrovascular tissue is performed using ophthalmic scissors and a scraper. In the case of complete SLN, a 360-degree peritomy is preliminarily performed outside the limbus. The vacuum ring is fixed on the eye surface and the head of the femtosecond laser is attached to it. During this, the surface of the cornea is leveled over the entire area of the applanation, the diameter of which is from 9 to 10 mm. After that, the cornea is scanned using the OCT laser built into the handle, the location, depth and configuration of the incisions are specified. The length of the tunnel, as well as the length of the incision, is 1.0 mm, its width is 0.5 mm, the total number of tunnels is 8-10. The orientation of the tunnel can be changed using the firmware, i.e. they can be oriented both tangentially and radially (in the range of 0-90 degrees). The tunnel depth is 200-330 µm. When forming each tunnel with a laser, first a cut is made perpendicular to the aligned corneal surface, and then an oblique cut, at an angle of 10-15 degrees to a plane parallel to the aligned corneal surface. The laser is activated and corneal tunnels are performed. The operating time of the laser is on average 35-45 seconds. Next, the vacuum is deactivated and the laser head with the vacuum ring is smoothly disconnected from the cornea. At 12 o'clock, a rectangular limbus flap is cut out from the recipient's eye, 1-1.5 in width and 2.0-2.5 mm in length, and divided into 8-10 fragments. One limb fragment is placed in each of the formed tunnels. As a protective coating, an amniotic membrane is applied to the entire surface of the cornea and fixed with a continuous absorbable suture (Vicryl 8-0) 2-3 mm outside the limbus.

There is a causal relationship between the set of essential features and the achieved technical result. The stage of formation of microtunnels is one of the most critical during the operation, since limbal flaps will be implanted in them. The more qualitatively and accurately the tunnel is formed, the more successful the engraftment and reliable fixation of limbal grafts, from which LESCs will migrate in the future, and form a new epithelial layer of the cornea.

This method ensures the formation of microtunnels uniform in depth and direction, their clear visualization, controllability and predictability of the process, thanks to a high-precision visualization system - OCT and embedded software. Thus, this method minimizes intraoperative risks, makes the operation more predictable, facilitates the postoperative period, and, as a result, accelerates the process of corneal re-epithelialization, improving the patient's quality of life.

The method is illustrated in Fig. 1-3, FIG. 1 shows a cornea with 8 radially oriented tunnels, top view, FIG. 2 shows the cornea with 10 tangentially oriented tunnels, top view, FIG. 3 - shows the cornea, at the time of applanation by a laser with tunnels, side view. Position 1 indicates the pupil, 2 - the location of the incision, 3 - the tunnel, 4 - the angle of the oblique cut, 5 - the cornea, 6 - the lens.

The method is illustrated by clinical examples

Example 1

Patient B., aged 45, diagnosis: OD neovascularized corneal leukoma (burn outcome), complete SLN.

On examination: Vis OS 1.0. Vis OD counting fingers on the face, does not correct. OCT of the cornea: OS without pathology. OD - irregular thinned epithelium, fibrous changes in the stroma, areas of absence of Vogt palisades, thickening of the cornea in the paracentral part up to 750 μm, with areas of thinning along the periphery. Minimum thickness 350 microns at 6 o'clock. An operation was performed to transplant a portion of the limbus from a healthy, contralateral eye to an eye with SLN using a low-energy femtosecond laser LDV Z8 according to the invention, while fixing a vacuum ring on the surface of the eye and attaching a femtosecond laser head to it. During this, the surface of the cornea is leveled over the entire area of the applanation with a diameter of 9 mm. The length of the tunnel, like the length of the cut, is 1.0 mm, its width is 0.5 mm, the number of tunnels is 8. The orientation of the tunnel is tangential. Tunnel depth 200 µm. Bevel cut angle 10 degrees. Next, the vacuum is deactivated and the laser head with the vacuum ring is smoothly disconnected from the cornea. A rectangular limbal flap 1 mm wide and 2.0 mm long is cut out from the recipient eye at 12 o'clock and divided into 8 fragments. One limb fragment is placed in each of the formed tunnels. In order to preserve the amniotic membrane covering the anterior surface of the cornea for a longer time, an SCL was additionally placed on the eye.

The patient was observed for 7 days in the hospital.

After 2 weeks, the SCL was removed, the amniotic membrane was completely lysed in the cornea, partially preserved in the limbus around the entire circumference. Epithelialization is complete, the epithelium is loose.

After 12 months, a decrease in superficial neovascularization, the formation of a stable epithelial cover and an increase in corneal transparency at OD were noted.

Example 2

Patient N., 45 years old, was hospitalized with a diagnosis of:

OS corneal neovascularization (burn outcome), complete SLN.

On examination: Vis OD 1.0. Vis OS 0.05.

Corneal OCT: OD without pathology. OS - irregular thinned epithelium, fibrous surface changes in the stroma and fibrovascular pannus, areas of absence of Vogt's palisades, compaction of the central part of the cornea up to 530 microns.

An operation was performed to transplant a portion of the limbus from a healthy, contralateral eye to an eye with SLN using a low-energy femtosecond laser LDV Z8 according to the invention, while fixing a vacuum ring on the surface of the eye and attaching a femtosecond laser head to it. During this, the surface of the cornea is leveled over the entire area of the applanation, the diameter of which is 10 mm. The length of the tunnel, like the length of the cut, is 1.0 mm, its width is 0.5 mm, the number of tunnels is 9. The tunnel is oriented radially. The tunnel depth is 250 µm. Bevel cut angle 15 degrees. Next, the vacuum is deactivated and the laser head with the vacuum ring is smoothly disconnected from the cornea. A rectangular limbal flap 1.5 mm wide and 2.5 mm long is cut out from the recipient eye at 12 o'clock and divided into 9 fragments. One limb fragment is placed in each of the formed tunnels. In order to preserve the amniotic membrane covering the anterior surface of the cornea for a longer time, an SCL was additionally placed on the eye.

The patient was observed for 7 days in the hospital.

After 2 weeks, the SCL was removed, the amniotic membrane was completely lysed in the cornea, partially preserved in the limbus around the entire circumference. Epithelialization is complete, the epithelium is loose.

After 12 months, a decrease in superficial neovascularization, the formation of a stable epithelial cover, and an increase in the transparency of the cornea on OS were noted.

Example 3

Patient A., aged 39, was hospitalized with a diagnosis of OS Corneal neovascularization (burn outcome), complete SLN.

On examination: Vis OD 1.0. Vis OS 0.03.

Corneal OCT: OD without pathology. OS - irregular thinned epithelium, fibrous surface changes in the stroma and fibrovascular pannus, areas of absence of Vogt's palisades, compaction of the central part of the cornea up to 610 microns.

An operation was performed to transplant a portion of the limbus from a healthy, contralateral eye to an eye with SLN using a low-energy femtosecond laser LDV Z8 according to the invention, while fixing a vacuum ring on the surface of the eye and attaching a femtosecond laser head to it. During this, the surface of the cornea is leveled over the entire area of the applanation, the diameter of which is 9 mm, the length of the tunnel, as well as the length of the incision, is 1.0 mm, its width is 0.5 mm, the total number of tunnels is 10. Tunnel orientation: radial. The tunnel depth is 330 µm. The angle of the oblique vertical cut is 10 degrees. Next, the vacuum is deactivated and the laser head with the vacuum ring is smoothly disconnected from the cornea. A rectangular limbal flap 1.5 mm wide and 2.0 mm long is cut out from the recipient's eye at 12 o'clock and divided into 10 fragments. One limb fragment is placed in each of the formed tunnels. In order to preserve the amniotic membrane covering the anterior surface of the cornea for a longer time, an SCL was additionally placed on the eye. The patient was observed for 7 days in the hospital.

After 2 weeks, the SCL was removed, the amniotic membrane was completely lysed in the cornea, partially preserved in the limbus around the entire circumference. Epithelialization is complete, the epithelium is loose.

After 12 months, a decrease in superficial neovascularization, the formation of a stable epithelial cover, and an increase in the transparency of the cornea on OS were noted.

Claims (2)

1. A method for restoring the epithelial layer of the cornea in unilateral limbal insufficiency syndrome (SLN) using a low-energy femtosecond laser, including excision of the fibrovascular pannus from the surface of the cornea of the affected eye, making superficial incisions in the periphery of the corneal stroma, forming a tunnel from each incision, dividing the cut out limbal flap into fragments, placing each fragment in a tunnel, applying an amniotic membrane to the surface of the cornea and fixing it, characterized in that after excision of the fibrovascular pannus, a vacuum ring is fixed on the surface of the affected eye and a femtosecond laser head is attached to it, after which the cornea is scanned using of the optical coherence tomography laser built into the handle, specify the location, depth and configuration of the incisions, from which 8-10 tunnels are then formed as follows: first, a cut is made, perp endicular corneal surface, and then an oblique cut, at an angle of 10-15 degrees to a plane parallel to the aligned corneal surface, then activate the laser and perform tangentially or radially located corneal tunnels 1.0 mm long, 0.5 mm wide and 200- 330 µm each, then the vacuum is deactivated and the laser head with the vacuum ring is smoothly disconnected from the cornea; a rectangular limbal flap 1-1.5 mm in width and 2-2.5 mm in length is cut out on the recipient's eye, divided into 8-10 fragments, one fragment of the limbus is placed in each of the formed tunnels, and placed on the amniotic membrane soft contact lens for 2 weeks. 2. The method according to claim 1, characterized in that in the case of complete SLN, before removing the fibrovascular pannus, a 360-degree peritomy behind the limbus is performed.

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