RU2638687C1 - Method for removing of opaque bubble layer arising during femtolazik operation - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: for correction of complications arising during the execution of the FemtoLAZIK operation when an island or islands of opaque bubble layer (OBL), spatula is used to acess the subvalvular space to the OBL island or islands, located in the pupil projection so that the spatula is in contact with the valve leg. The spatula is taken out of the subvalvular space, then a tool with a spherical tip or a spatula is used to perform light neat movement along the valve corneal epithelium from the OBL island or islands towards the output channel formed by the spatula near the valve leg. Then these same tools are used to perform circular motion from the center of the cornea to its periphery until the OBL in the pupil projection disappear, then the corneal valve is lifted using a spatula. In case of residual OBL in the stromal bed of the cornea after valve lifting, a tool with a spherical tip or a spatula is used perform circular movements along the stromal bed surface from the center to the periphery of the cornea till the complete disappearance of OBL.

EFFECT: method allows to perform excimer laser correction of refraction using an eye tracking system, which prevents formation of irregular corneal surface and irregular astigmatism and reduce time of manipulation with the corneal valve, which reduces the risk of epithelial desquamation, valve oedema, expressed reduction of valve collagen fibers, that allows to perform adequate alignment of wound edges at the end of the operation and reduces the risk of valve microstriae formation.

2 cl, 2 ex

Description

The invention relates to medicine, namely to ophthalmology, and can be used to eliminate the opaque bubble layer that occurs during the FemtoLASIK operation.

Valve refractive surgery, such as in situ laser keratomileusis using a mechanical microkeratome (LASIK) and a femtosecond laser (FemtoLASIK), occupy a confident leading position in modern ophthalmologist practice in correcting refractive errors. With the advent of the femtosecond laser in ophthalmic practice, refractive laser operations have become more efficient, safer and more predictable. It was also possible to reduce the number of complications associated with the work of microkeratome during the formation of the corneal valve in order to correct refractive errors (Pateeva TZ Femtolaser correction of myopia. Abstract of diss. ... Candidate of Medical Sciences. - Moscow, 2012. - 23 p.) .

The principle of operation of a femtolaser is based on photodestruction of the tissue: a laser with an infrared wavelength (~ 1050 nm) generates ultrashort pulses and focuses them in the cornea at a given depth. As a result of the interaction of the laser with the tissue, a plasma is formed of electrons and ions, which, due to its expansion and the formation of an acoustic wave, performs stratification of the cornea. During photodestruction, a small amount of tissue is removed with the formation of cavitation bubbles consisting of carbon dioxide and water. Part of the cavitation vesicles is scattered into the surrounding tissue, and the other part is removed when the corneal valve rises. Stratification of the cornea using a femtosecond laser is called femtodissection (Kostenev S.V. The modern concept of corneal surgery based on the use of a femtosecond laser. Dis .... Dr. med. Sciences. - Moscow, 2014. - 269 p.).

Features of the process of femtodissection of the cornea led to the appearance of specific complications, such as: vertical and horizontal gas breakthrough, opaque bubble layer (NPS). Among these complications, the most common NPS. This complication in the practice of an ophthalmologist can occur in 48% of cases of FemtoLASIK operations (Courtin R., Saad A., Guilbert E., Grise-Dulac A., Gatinel D. Opaque Bubble Layer Risk Factors in Femtosecond Laser-assisted LASIK // J. Refract. Surg. - 2015. - Vol. 31. - No. 9. - P. 608-612).

NPS is characterized by the accumulation of gas in the intralamellar space with possible propagation both along the collagen fibers and across if their integrity is violated along the path of least resistance. Distinguish between “soft” and “rough” islands of the NPS. The latter are characterized by a more pronounced intensity than the “soft” ones. The appearance of “rough” NPS islands can be accompanied by pronounced uncut portions of the corneal stroma (“tissue bridges”) (Kaiserman I., Maresky HS, Bahar I., Rootman DS Incidence, possible risk factors and potential effects of an opaque bubble layer created by a femtosecond laser // J. Cataract. Refract. Surg. - 2008. - Vol. 34. - No. 3. - P. 417-423).

J., Huhtala A.,

P., Uusitalo H. Flap characteristics, predictability and safety of the Ziemer FEMTO LDV femtosecond laser with the disposable suction ring for LASIK // Eye (Lond). - 2014. - Vol. 28. №1. - p. 66-71).NPS leads to difficulties in focusing an excimer laser and an eye tracking system. Problems in the operation of the tracking system for eye movement can lead to the formation of an irregular surface of the cornea with the appearance of irregular astigmatism or to an increase in its degree with the correction of such ametropias, a marked increase in aberrations when the patient's gaze changes during excimer laser ablation. This subsequently forces the correction of induced astigmatism with subsequent repeated refractive laser and / or surgical interventions, a long rehabilitation period and often not one hundred percent visual and refractive result due to the formation of a complex aberration optical system of the eye. The presence of an NPS in the thickness of the stromal bed, which persists after lifting the corneal valve, forces the surgeon to postpone excimer laser ablation for the time necessary for the resorption of the NPS (from 30 to 90 minutes). This is accompanied by desquamation of the corneal epithelium, the formation of corneal valve edema, the reduction of collagen valve fibrils, which subsequently leads to the appearance of valve microstria and an inadequate comparison of the edges of the corneal valve and the diameter of the stromal bed. The inability to perform FemtoLASIC surgery according to the standard protocol (without a forced pause for the time of NPS resorption) can lead to a change in the corneal ablation coefficient. All this reduces the predictability, effectiveness and safety of FemtoLASIC surgery. It was noted that the appearance of an NPS during the FemtoLASIC operation can lead to a decrease in the maximum corrected visual acuity in the distance by 2 lines according to the Snellen table (this is equivalent to a 1.6-fold decrease), i.e. according to the Golovin-Sivtsev tables, for example, approximately: from 1, 0 to 0.6 (on 4 lines), from 0.8 to 0.5 (on 3 lines), from 0.5-0.6 to 0.3-0.4 (on 2 lines), from 0, 3 to 0.2 (per 1 line)

J., Huhtala A.,

P., Uusitalo H. Flap characteristics, predictability and safety of the Ziemer FEMTO LDV femtosecond laser with the disposable suction ring for LASIK // Eye (Lond). - 2014 .-- Vol. 28. No. 1. - p. 66-71).

A known method of treating myopia (RF patent for the invention No. 2367397), according to which laser in situ laser keratomileusis (LASIK) is performed with resection of the corneal flap (valve). Corneal flap resection is performed using an IntraLasik femtosecond laser. The diameter of the corneal flap is 8.0-9.5 mm, the thickness is 90-120 microns, and the angle determining the width of the corneal flap leg is from 45 to 90 degrees. Then excimer laser ablation is performed.

The disadvantage of this method is the possible occurrence of NPS. Such a complication can lead to difficulties in focusing the excimer laser and problems in the operation of the eye tracking system with the subsequent formation of an irregular surface of the cornea, accompanied by irregular astigmatism, as well as a decrease in the clinical and functional results of the operation.

The closest analogue of the proposed method is a method for correcting complications arising from performing the FemtoLASIK operation (RF patent for invention No. 2462215), which consists in the formation of a corneal valve under local anesthesia using a femtosecond laser followed by excimer laser ablation of the corneal stroma. If complications arise, the ablation parameters are recalculated and the corneal valve is re-formed using a mechanical microkeratome, while the depth of the corneal valve formation is increased by at least 20 μm, the valve diameter is increased by at least 0.5 mm, and the diameter of the ablation zone is reduced by at least less than 0.5 mm depending on the average thickness of the cornea. Next, excimer laser ablation of the corneal stroma is performed.

The disadvantage of the above method is the use of a mechanical microkeratome for re-cutting the corneal valve, including the planned increase in the depth of cut by 20 microns. It is also known that a deviation from a given thickness during the formation of the corneal valve by a mechanical microkeratome can reach 140 μm, a similar error in the operation of a mechanical microkeratome can lead to a serious complication - induced keratectasia with subsequent prolonged (for several years), not always successful treatment (Spadea L. , Palmieri G., Mosca L., Fasciani R., Balestrazzi E. Iatrogenic keratectasia following laser in situ keratomileusis // J. Refract. Surg. - 2002. - Vol. 18. - No. 4. - P. 475-480) . Another disadvantage of the above method is to reduce the diameter of the optical zone by at least 0.5 mm, which can lead to a deterioration in twilight vision, the appearance of the effects of "halo" and "glare".

The task of the invention is to develop a method for eliminating an opaque bubble layer that occurs during the operation of FemtoLASIK.

The technical result of the developed method is:

- providing the possibility of excimer laser correction of refractive errors using an eye tracking system that prevents the formation of an irregular corneal surface and irregular astigmatism;

- reducing the time of manipulation of the corneal valve, which reduces the risk of desquamation of the epithelium, valve edema, a pronounced reduction in the collagen fibers of the valve, which allows an adequate comparison of the edges of the wound at the end of the operation and reduces the risk of valve microstria formation;

- a slight change in the coefficient of corneal ablation, which corresponds to the standard protocol of the FemtoLASIK operation, which will not require additional adjustments to the calculation parameters of the operation.

All this will lead to high clinical and functional results of the operation.

The specified technical result is achieved by the fact that in the method for correcting complications arising from the FemtoLASIK operation, according to the invention, when a “soft” island or “soft” islands of an opaque bubble layer (NPS) occurs, a spatula enters the undervalve space up to the island or islands of the NPS located / located in the projection of the pupil, so that the spatula is in contact with the valve leg, remove the spatula from the subvalvular space, then using a tool with a spherical tip coma or spatula perform light, gentle movements along the valve corneal epithelium from the islet or islands of the NPS in the direction to the outlet channel created by the spatula at the valve leg, then these same instruments use circular diverging movements from the center of the cornea to its periphery until the NPS disappears into the pupil projection, after which with a spatula lift the corneal valve.

If there is a residual NPS in the thickness of the stromal bed of the cornea after raising the valve with the help of a tool with a spherical tip or spatula, circular movements are performed on the surface of the stromal bed in the direction from the center to the periphery of the cornea until the NPS completely disappears.

There is a causal relationship between the totality of the actions performed and the technical result achieved.

Creating an outlet channel with a spatula until the corneal valve rises, followed by gentle, gentle movements of the instrument with a spherical tip or spatula along the corneal epithelium in the direction from the NPS to the formed channel, further light circular diverging movements along the corneal epithelium and circular movements of the above instruments on the surface of the stromal bed elimination of NPS, which allows you to bring to working condition a tracking system for eye movement, which responds to deviation the patient’s gaze during excimer laser ablation and prevents the formation of an irregular surface of the cornea, irregular astigmatism. Also, the time of manipulation with the corneal valve is reduced, which reduces the risk of desquamation of the epithelium, valve edema, a pronounced reduction in the collagen fibers of the valve, which allows an adequate comparison of the edges of the wound at the end of the operation and reduces the risk of valve microstria formation, besides, only a slight change in the corneal ablation coefficient occurs , which corresponds to the standard protocol of the FemtoLASIK operation and does not require additional adjustments to the calculation parameters of the operation. All this contributes to the achievement of high clinical and functional results of the FemtoLASIK operation.

Example 1

Patient O., 29 years old, turned to the IRTC “MG” with complaints of low visual acuity in the distance without spectacle correction. Myopia suffers from 13 years. He constantly uses glasses. A standard examination of a patient with pathology of refraction was performed. Visual acuity without correction: right eye 0.04, left eye 0.04. Spectral correction sphere -5.5 diopters in both eyes. The maximum corrected visual acuity of 1.0 in both eyes. IOP right eye - 20 mm RT. Art., left eye 19 mm RT. Art. No data were found for keratoconus. Diagnosed with moderate stationary myopia. It was decided to perform myopia correction using the FemtoLASIK operation, with the formation of a corneal valve with a thickness of 100 μm, a diameter of 9.0 mm and a cut-in angle of the valve edge of 70 ° and a valve leg at 12 hours. Immediately after the valve was formed by a femtosecond laser, a “soft” island of an opaque bubble layer was found in the projection of the pupil on the right eye, which did not allow excimer laser ablation using an eye tracking system.

It was decided to carry out further steps of the operation using the claimed method, for which the spatula entered the subvalvular space to the island of the NPS located in the projection of the pupil, so that the spatula was in contact with the valve leg. Then they removed the spatula from the subvalvular space. Then, using a tool with a spherical tip, light, gentle movements were made along the epithelium of the valve cornea from the island of the NPS towards the outlet channel created by the spatula at the valve leg, then the same instrument circulated diverging from the center of the cornea to its periphery until the NPS disappeared in the pupil projection. After that, with the help of a spatula, the corneal valve was lifted, as a result of which the NPS disappeared completely within one minute and excimer laser correction was performed using the eye movement tracking system according to the parameters calculated at the preoperative stage. Visual acuity on the first day after surgery: right eye 1.0, left eye 1.0. 1 month after surgery, visual acuity: right eye 1.0, left eye 1.0, autorefractometry data: right eye sphere -0.25 diopters, left eye sphere -0.25 diopters. 1 year after surgery, visual acuity: right eye 1.0, left eye 1.0.

Example 2

Patient D., 25 years old, turned to the IRTC “MG” with complaints of low visual acuity in the distance without spectacle correction. Myopia suffers from 12 years. He constantly uses glasses and contact lenses. A standard examination of a patient with pathology of refraction was performed. Visual acuity without correction: right eye 0.08, left eye 0.08. Spectral correction sphere -3.75 diopters in both eyes. The maximum corrected visual acuity is 1.2 in both eyes. IOP right eye - 18 mm RT. Art., left eye 18 mm RT. Art. No data were found for keratoconus. Diagnosed with moderate stationary myopia. It was decided to perform myopia correction using the FemtoLASIK operation with the formation of a corneal valve with a thickness of 100 μm, a diameter of 9.0 mm and an angle of incidence of the edge of the valve 700 and the valve leg at 12 hours. Immediately after the valve was formed by a femtosecond laser, “soft” islands of an opaque bubble layer in the projection of the pupil were discovered on the left eye, which did not allow excimer laser ablation using the eye tracking system. It was decided to carry out further steps of the operation using the claimed method, for which the spatula entered the valve space to the islands of the NPS located in the projection of the pupil, so that the spatula was in contact with the valve leg. Then they removed the spatula from the subvalvular space. Then, with the help of a spatula, we performed light, neat movements along the valve corneal epithelium: from the islands of the NPS in the direction to the outlet channel created by the spatula at the valve leg, then with the same tool, circular diverging from the center of the cornea to its periphery until the part of the NPS in the pupil projection disappeared. Then, using a spatula, the corneal valve was lifted. After that, in the projection of the pupil in the thickness of the stromal bed of the cornea, residual NPS islands were visualized that did not allow excimer laser ablation using an eye tracking system. To remove the islands of residual NPS using a spherical tip tool, circular motions were performed along the surface of the stromal bed in the direction from the center to the periphery of the cornea until the NPS completely disappeared.

As a result of this, the NPS completely disappeared within one minute and excimer laser correction was performed using the eye movement tracking system according to the parameters calculated at the preoperative stage. Visual acuity on the first day after surgery: right eye 1.2, left eye 1.2. 1 month after surgery, visual acuity: right eye 1.2, left eye 1.2, autorefractometry data: right eye sphere 0.25 diopters, left eye sphere 0.25 diopters. 1 year after surgery, visual acuity: right eye 1.2, left eye 1.2.

Using the claimed invention, 337 eyes were operated on. In all cases, the planned refraction and high clinical and functional results were achieved.

Claims (2)

1. A method for correcting complications arising from the FemtoLASIK operation, characterized in that when an island or islands of an opaque bubble layer (NPS) occurs with a putty knife, they enter the subvalvular space to an island or islands of an NPS located or located in the projection of the pupil, so that the spatula in contact with the valve leg, take the spatula out of the subvalvular space, then use the tool with a spherical tip or spatula to make light, gentle movements along the epithelium of the horn Itza valve from an island or islands NPS created towards the spatula at the valve foot outlet duct, then these same tools - diverging circular motion from the corneal center to its periphery until disappearance NPS in the projection pupil, then with a spatula operate lifting corneal flap. 2. The method according to p. 1, characterized in that in the presence of residual NPS in the thickness of the stromal bed of the cornea after lifting the valve with a spherical tip or spatula, circular movements are performed along the surface of the stromal bed in the direction from the center to the periphery of the cornea until the NPS completely disappears .