RU2733319C1 - Method for correction of high degree of myopia in patients with thin cornea - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, specifically to ophthalmology. For correction of high degree of myopia in patients with thin cornea on one eye and with normal thickness of cornea in contralateral eye using method ReLex SMILE in eye with normal thickness of cornea, lenticule is formed and extracted. Then a valve is formed in the eye with a thin cornea by Femto LASIK method, and a lenticule is implanted on its stromal bed, and the valve is returned to the previous place. Then one month later, the valve is tilted, the first keratectomy is performed with the help of an excimer laser with the ablation diameter from 5.5 mm to 6.0 mm, the ablation depth is from 25 mcm to 30 mcm, the valve is returned to the previous place. Then, one month after the first keratectomy, the valve is tilted, the second keratectomy is performed with the help of an excimer laser on the entire thickness of the lenticule with the part of the cornea own tissue captured: depth of ablation from 150 mm to 160 mm, wherein in the lenticule a through hole is made, forming a ring, after which the valve is returned to the previous place.

EFFECT: method improves visual acuity in patients with a thin cornea and eliminates the risk of rejection of lenticule by implantation of the autologous lenticule.

1 cl, 2 ex, 6 dwg

Description

The invention relates to medicine, namely to ophthalmology, and can be used to correct a high degree of myopia in patients with a thin cornea in one eye and with a normal corneal thickness in the contralateral eye.

For patients with a high degree of myopia and a thin cornea, there are a number of limitations when choosing keratorefractive interventions. One of the most important criteria is the thickness of the central optical zone of the cornea.

According to the world literature, there are various surgical approaches to correcting a high degree of myopia in patients with a thin cornea. However, not in all cases it is possible to apply surgical technologies for treating patients with this pathology, since there is a high risk of developing postoperative corneal keratectasia.

A known method for correcting high myopia and complex myopic astigmatism in patients with a thin cornea, in which the first stage is the implantation of a phakic intraocular lens (PIOL). 1 month after the first stage, the next stage is performed, which consists in conducting arcuate keratotomy using a femtosecond laser in order to compensate for myopic astigmatism according to previously developed parameters, depending on the magnitude of the degree of astigmatism to a depth of 90% of the corneal thickness (RF Patent for invention No. 2688016 ).

The disadvantage of the described method is the need and complexity of strict adherence to the rules for the implantation of PIOL. In particular, such parameters of the eye as: the depth of the anterior chamber of the eye and the density of corneal endothelial cells. In addition, when the PIOL is displaced, there may be a violation of the outflow of intraocular fluid between the anterior and posterior chambers of the eye and, as a result, glaucoma may develop. There is also a risk of developing cataracts after PIOL implantation in older people.

The closest analogue is a method of treating keratoconus and correcting high myopia in patients with a thin cornea, in which a ring-shaped intrastromal tunnel with an inner diameter of 3 to 5 mm and an outer diameter of 7-9 mm at a depth of 250-350 microns is formed using a femtosecond laser. ... Intrastromal open ring is implanted into the tunnel, which closes at its ends in a "lock" type. The width of the tunnel cut is 1.0 to 3.0 mm and the length is 0.5 to 3.0 mm. This method makes it possible to achieve a flattening of the central zone of the cornea, improve visual acuity and restore the sphericity of the cornea (RF Patent for invention No. 2584087)

The disadvantage of the described method is that the open intrastromal ring has rigid properties, can exert pressure on the surrounding corneal tissue and cause extrusion with the subsequent development of keratitis. In addition, the open intrastromal ring is not part of the native cornea, which could potentially trigger a foreign material rejection reaction.

The objective of the claimed invention is to develop a method for treating patients with high myopia and a thin cornea using a femtosecond laser to obtain corneal tissue from one eye with a normal corneal thickness, followed by its implantation into the other eye with a thin cornea and two-stage ablation using an excimer laser.

The technical result obtained as a result of solving this problem consists in functional improvement of visual acuity in patients with a high degree of myopia in patients with a thin cornea due to the implantation of their own (autologous) corneal tissue (lenticula).

Autologous lenticula possesses optimal and natural natural properties of rigidity, which significantly reduces the risks of its extrusion and eliminates the risk of rejection in the future.

The specified technical result is achieved by the fact that in the method for correcting a high degree of myopia in patients with a thin cornea, including intrastromal implantation of the ring, according to the invention, in patients with a thin cornea in one eye and with a normal corneal thickness in the contralateral eye, using the ReLex SMILE method in an eye with a normal corneal thickness is formed and a lenticule is removed, then a valve is formed in an eye with a thin cornea using the Femto LASIK method, a valve with a diameter of 8.0 mm to 8.5 mm, a thickness of 110 μm, then the valve is folded back, and a lenticula is implanted on the stromal bed, then one month later, keratectomy (first keratectomy) is performed using an excimer laser with an ablation zone diameter of 5.5 mm to 6.0 mm, ablation depth from 25 μm to 30 μm, then one month after the first keratectomy, a second keratectomy is performed using an excimer laser for the entire thickness of the lenticule with the capture of part of the corneal tissue: ablation depth from 150 mm to 160 mm, with a through hole is made in the lenticule, forming a ring, with an inner diameter from 5.5 mm to 6.0 mm, with an outer diameter from 7.5 mm to 8.0 mm, and a concave surface in the central optical zone from the corneal tissue corneas with a diameter matching the inner diameter of the ring, with a height of 70 μm to 75 μm, after which the valve is returned to its original place.

The method is illustrated by Figures 1-6. FIG. 1 shows the second stage of the operation, top view of the operated eye, FIG. 2 - the second stage of the operation, a cross-section of the operated eye, FIG. 3 - the third stage of the operation, top view of the operated eye, FIG. 4 - the third stage of the operation, a cross-section of the operated eye with the ablation zone of its own corneal tissue, in Fig. 5 - the final result of the operated eye, top view, with the resulting ring from the lenticula, in Fig. 6 is a cross-section of the operated eye.

Position 1 denotes the lenticule, 2 - the corneal valve, 3 - the projection of the ablation zone of the protruding part of the lenticula, 4 - the height of the protruding part of the lenticula, 5 - the projection of the ablation zone of the lenticula, 6 - the diameter of the ablation zone of the lenticula, 7 - the distance from the concave part of the lenticule to the posterior surface valve cover, 8 - a ring obtained from the lenticule, 9 - the outer diameter of the ring, 10 - the inner diameter of the ring.

The method of treatment according to the invention is carried out as follows.

First, an eye with a normal corneal thickness is operated under local drip anesthesia using a VisuMax femtosecond laser (pulse repetition rate 500 kHz, pulse energy 160 nJ) using ReLex SMILE technology, at the same time the bottom of the lenticula is formed, and then its "cap". The diameter of the bottom of the lenticula is from 7.0 to 7.5 mm, and the diameter of the lid is 0.5 or 1.0 mm larger than the diameter of the bottom, depending on the initial corrected refraction of the eye. The lid thickness is 110 µm or 115 µm. At 12 o'clock, a femtosecond one-sided incision with a length of 2.0 mm to 4.2 mm at an angle of 90 degrees is performed, with the formation of an intrastromal pocket. At the end of the laser operation, use a spatula to separate the cover and the bottom of the lenticle. The lenticle is then removed with forceps through the incision. Using a spatula and Trypan blue dye, a mark is made in the center of the lenticule on its front surface, staining will help to facilitate the centering of the lenticule relative to the center of the visual axis of the eye. The lenticule is transferred into a previously prepared bottle containing the Borzenk-Moroz conservation medium (RF Patent for invention No. 2069951). The vial contains the following data: date and time of the operation, number of the patient's outpatient card, patient's eye, entered laser parameters. The intrastromal pocket is flushed with balanced salt solution (BSS). The vial containing the lenticule is placed in a special container with a hypothermic regime and stored in the operating room for 10-20 minutes, that is, during operations on two eyes.

In the second eye of a patient with a thin cornea, the first stage is to form a corneal valve using a WaveLight FS200 femtosecond laser (pulse repetition rate 200 kHz, pulse energy 0.9 μJ), while the incision angle of the valve edge is 70 degrees, the valve diameter is from 8, 0 mm to 8.5 mm, valve thickness 110 microns. The valve is folded back with a special spatula. Next, the lenticle is removed from the vial, washed with BSS solution for 45 seconds to remove excess staining and placed on the stromal bed, centered on the visual axis and pupillary center. The valve is placed on the stromal bed. An antibiotic solution is instilled. One month after achieving stability of refraction, the eyes go to the second stage (Fig. 1). Intraoperatively, under local anesthesia, the valve is thrown from the corneal bed with a spatula, keratectomy is performed using the Wavelight Allegretto EX 500 excimer laser (power 500 Hz, spot diameter 680 μm), while the ablation zone diameter was 5.5 mm - 6.0 mm, ablation depth was 25 μm - 30 μm) (Fig. 2). The corneal valve is returned to the stromal bed. The subvalvular space was flushed with BSS solution, the valve was smoothed with a swab until it adhered completely. The original form of the lenticule has an uneven thickness throughout its entire length, namely, its greatest thickness is in the center with thinning towards the periphery. This leads to instability of the biomechanical properties of the cornea and to the difficulty of tuning the excimer laser for further ring formation (Fig. 5). To solve these problems, it is necessary to form a lenticule with the same thickness throughout its entire length using an excimer laser (Fig. 4).

One month after the second stage, the third stage is carried out. Under topical anesthesia, the valve is carefully separated and folded back with a spatula. Then, the Wavelight Allegretto EX 500 excimer laser (power 500 Hz, spot diameter 680 μm) is set to such parameters that will allow keratectomy to be performed over the entire thickness of the lenticule with the capture of a part of the corneal tissue (the ablation depth ranged from 150 μm to 160 μm), while a through hole is made in the lenticule, forming a ring, with an inner diameter of 5.5 mm to 6.0 mm, an outer diameter of 7.5 mm to 8.0 mm, and a concave surface in the central optical zone of the cornea ( CPOR) with a diameter that matches the inner diameter of the ring, with a height of 70 μm to 75 μm (Fig. 4). The ring (Fig. 5) and the depression in the CPRT promote tension of the overlying corneal tissues, which leads to their flattening over the CPRR in the plane of the ring (Fig. 6), and, therefore, myopia is compensated. The valve is returned to its original position. An antibiotic solution is instilled into the conjunctival cavity. The ring, which in cross-section has the shape of an oval, due to its natural stiffness and smooth (streamlined) oval shape, has a minimal effect on the surrounding corneal tissue and therefore eliminates the risk of extrusion of the ring. In addition, it is known that immune rejection reactions occur in the presence of foreign material, but since the ring in this method is by its origin part of the corneal tissue's own tissue, the risk of immune rejection is significantly reduced.

The proposed method is illustrated by the following examples.

Example 1

Patient J., 27 years old, turned to the department of refractive laser surgery with complaints of low vision at the Federal State Autonomous Institution "MNTK" MG "named after Academician SN Fedorov" of the Ministry of Health of the Russian Federation. From the anamnesis it was found that low vision in the right eye in a patient aged 10 years. She uses permanent glasses with incomplete correction.

A complete ophthalmological examination was performed.

Diagnostic data before surgery:

Visometry:

OD 0.01sph - 13.0 = 0.08; OS 0.02 sph - 7.75 = 0.8

Refractometry:

ODsph - 13.0 cyl - 0.25 ax 25; OS sph - 7.75 cyl - 0.25 ax 15

Eye length: OD - 27.69 mm; OS - 26.35 mm.

Keratometry: ODK1 46.75 ax 24 °, K2 47.00 ax 114 °, AVE 46.75, cyl 0.25 ax 24 °; OS: K1 45.25 ax 15 °, K2 45.50 ax 105 °, AVE 45.25, cyl 0.25 ax 15 °

Ultrasonic pachymetry of the central corneal thickness: OD 496; OS 573

Tonometry within normal values: OD: 17 mm. RT.art .; OS: 16mm. Hg

According to the results of keratotopography OD, the thickness of the cornea in the center is 506 μm; keratometry: K1 46.75, K2 47.00; cyl 0.25 ax 25.2 °. OS is the thickness of the cornea in the center 578 µm; keratometry: K1 45.25, K2 45.50; cyl 0.30 ax 15.2 °.

The patient was diagnosed with OD High myopia. Severe refractive amblyopia. OS Myopia high. Anisometropia.

The patient underwent keratorefractive surgery according to the invention.

Parameters of a lenticule extracted from a left eye with a normal thickness (bottom diameters 7.0 mm, cover 7.5 mm, lenticule thickness 110 μm). The valve diameter during the first stage in the right eye was 8.0 mm. During the second stage of the operation, the ablation zone of the autologous lenticula was 5.5 mm, the ablation depth was 25 μm.

During the third stage of the operation, the ablation zone of the autologous lenticule was 5.5 mm, the ablation depth was 150 μm. A ring with an inner diameter of 5.5 mm and an outer diameter of 7.5 mm was formed in the lenticule, and a concave surface was formed from the corneal tissue in the CPOR with a diameter of 5.5 mm and a height of 70 μm. The patient is prescribed a standard treatment regimen after surgery.

Survey data on the next day after the third stage of the operation:

Visometry:

OD = 0.1; OS = 0.8

Keratometry: ODK1 35.5 ax 23 °, K2 35.75 ax 112 °, AVE 35.5, cyl 0.25 ax 23 °; OS: K1 38.75 ax 15 °, K2 39.00 ax 105 °, AVE 39.00, cyl 0.25 ax 15 °

Example 2

Patient A., 29 years old, turned to the department of refractive laser surgery at the Federal State Autonomous Institution "MNTK" MG "named after Academician SN Fedorov" of the Ministry of Health of the Russian Federation in order to resolve the issue of the possibility of performing refractive laser vision correction. According to the patient: he has been using permanent wearing glasses with incomplete correction since school age.

A complete ophthalmological examination was performed.

Diagnostic data before surgery:

Visometry:

OD 0.02sph - 10.0 = 0.1; OS 0.01 sph - 8.75 = 0.9

Refractometry:

OD sph - 10.0 cyl - 0.25 ax 35; OS sph - 8.75 cyl 0.0 ax 0

Eye length: OD - 26.54 mm; OS - 25.28 mm.

Keratometry: OD K1 43.75 ax 33 °, K2 44.00 ax 123 °, AVE 43.75, cyl 0.25 ax 33 °; OS: K1 45.50 ax 15 °, K2 45.75 ax 105 °, AVE 45.50, cyl 0.25 ax 15 °

Ultrasonic pachymetry of the central corneal thickness: OD 502; OS 578

Tonometry within normal values: OD: 16 mm. RT.art .; OS: 18 mm. Hg

According to the results of keratotopography OD, the thickness of the cornea in the center is 501 μm; keratometry: K1 43.75, K2 44.00; cyl 0.25 ax 33.1 °. OS corneal thickness in the center 581 µm; keratometry: K1 45.50, K2 45.75; cyl 0.20 ax 15.3 °.

The patient was diagnosed with OD High myopia. Severe refractive amblyopia. OS Myopia high. Anisometropia.

The patient underwent keratorefractive surgery according to the invention.

Parameters of a lenticule extracted from a left eye with a normal thickness (bottom diameter 7.5 mm, cover 8.0 mm, lenticule thickness 115 μm). The valve diameter during the first stage in the right eye was 8.5 mm. During the second stage of the operation, the ablation zone of the autologous lenticula was 6.0 mm, the ablation depth was 30 μm.

During the third stage of the operation, the ablation zone of the autologous lenticule was 6.0 mm, the ablation depth was 160 μm. A ring with an inner diameter of 6.0 mm and an outer diameter of 8.0 mm was formed, and a concave surface was formed from the corneal tissue in the CPOR with a diameter of 6.0 mm and a height of 75 microns. The patient is prescribed a standard treatment regimen after surgery.

Survey data on the next day after the third stage of the operation:

Visometry:

OD = 0.1; OS = 0.9

Keratometry: OD K1 38.75 ax 22 °, K2 39.0 ax 112 °, AVE 35.5, cyl 0.25 ax 23 °; OS: K1 37.75 ax 15 °, K2 38.00 ax 105 °, AVE 37.75, cyl 0.25 ax 15 °

Thus, the above examples demonstrated the possibility of effective and safe treatment of high grade myopia with thin cornea in one eye and normal corneal thickness in the contralateral eye. Adding your own corneal tissue to the naturally thin cornea eliminates the possibility of keratectasias and tissue rejection in the future. The formed ring of lenticulum makes it possible to correct myopia with high precision.

Claims (1)

A method of correcting a high degree of myopia in patients with a thin cornea, including intrastromal implantation of a ring, characterized in that in patients with a thin cornea in one eye and a normal corneal thickness in the contralateral eye, using the ReLex SMILE method in an eye with a normal corneal thickness, the cornea is formed and removed lenticula, then in an eye with a thin cornea using the Femto LASIK method, a valve is formed, the diameter of which is from 8.0 mm to 8.5 mm, the thickness is 110 μm, then the valve is folded back and the lenticula is implanted on the stromal bed, the valve is returned to its original place, then through one month the valve is reclined, the first keratectomy is performed using an excimer laser with a diameter of the ablation zone from 5.5 mm to 6.0 mm, the depth of ablation is from 25 μm to 30 μm, the valve is returned to its original place, then one month after the first keratectomy the valve recline, carry out a second keratectomy using an excimer laser for the entire thickness of the lenticule with the capture of a part of the corneal tissue: deep bin of ablation from 150 mm to 160 mm, while a through hole is made in the lenticule, forming a ring with an inner diameter from 5.5 mm to 6.0 mm, with an outer diameter from 7.5 mm to 8.0 mm, and from its own corneal tissue - a concave surface in the central optical zone of the cornea with a diameter that matches the inner diameter of the ring, with a height of 70 μm to 75 μm, after which the valve is returned to its original place.

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