RU2729361C1 - Method of forming an input cut for removal of lenticule in the process of laser vision correction by technology of intrastromal removal of lenticule - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely to ophthalmology, and can be used for formation of input cut for removal of lenticule, in process of laser vision correction by technology of intrastromal removal of lenticule. After femtolaser formation by means of femtolaser system "VisuMax" of the bottom of the lenticule, lateral cut of the lenticule, "cap" of the lenticule and unformed input cut for removal of the lenticule, removal of the femtolaser system from the patient's eye is performed. Further, an input cut is formed by means of a diamond knife for radial keratotomy, pre-setting the depth of blade from 100 to 160 mcm, which corresponds to the depth of the "cap" of the lenticule. Cut are formed in projection of edge of lenticule cap, which is determined along boundary of bubble layer, when forming the cut, the blade of the knife is installed perpendicular to the surface of the cornea, after which by continuous movement form cut 2–4 mm long along an arc of a circle corresponding to the projection of the lenticule cap.

EFFECT: method provides predictable and safe elimination of intraoperative complication of unformed input cut for removal of lenticule by laser vision correction by technology of intrastromal removal of lenticule (SMall Incision Lenticula Extraction – SMILE).

1 cl, 2 dwg, 1 tbl, 3 ex

Description

The invention relates to medicine, in particular to ophthalmology, and can be used to eliminate an intraoperative complication, an unformed entrance cut to remove a denticle, in the process of laser vision correction using the technology of intrastromal lenticula removal (SMall Incision Lenticula Extraction - SMILE).

In 2008, Carl Zeiss developed a unique technology for laser vision correction - SMILE, which is performed on the VisuMax femtolaser system. The uniqueness of this technology lies in the formation of a lenticule in the thickness of the corneal stroma, which is then removed after a 2-4 mm entrance incision. The process of lenticular formation is one of the key stages of the operation; it occurs after the femtolaser is docked with the patient's eye and lasts an average of 25-30 seconds. Thus, the SMILE technology is valveless, and also allows not to violate the integrity of the epithelium (with the exception of a small area of the entrance cut through which the lenticule is removed), which gives it an indisputable advantage over alternative technologies for laser vision correction (Photorefractive keratectomy (PRK), Laser-Assisted in Situ Keratomileusis (LASIK)). The advantages of this technology include: high stability of the biomechanics of the cornea, a relatively low risk of developing dry eye syndrome, no complications associated with the valve (valve folds, displacement or detachment), fast postoperative rehabilitation due to the absence of damage to the corneal epithelium.

However, in the course of operations using this technology, intraoperative complications are encountered, one of which is an unformed entrance incision for removing the lenticula, the cause of which is the breakdown of the vacuum.

The closest analogue of eliminating this complication is the Circle program provided in the VisuMax femtosecond system, which allows transferring the lenticular cover into the valve with the subsequent completion of the operation using Femtosecond Lenticule Extraction (FLEX) technology, or LASIK using an excimer laser (Riau AK , Ang HP, Lwin NC, Chaurasia SS, Tan DT, Mehta JS. Comparison of four different VisuMax circle patterns for flap creation after small incision lenticule extraction. J Refract Surg 2013; 29: 236-44). The described method has a significant disadvantage associated with the transfer of valveless technology to valve technology, thereby depriving it of all the declared advantages.

The objective of the claimed invention is to develop a predictable and safe method for eliminating an intraoperative complication, an unformed entrance cut for removing the lenticula, during laser vision correction using SMILE technology.

The technical result obtained as a result of solving the problem is the predictable and safe elimination of the intraoperative complication of an unformed entrance cut to remove the lenticule during laser vision correction using the SMILE technology.

The technical result of the method for eliminating an intraoperative complication, an unformed incision for removing the lenticule, during laser vision correction using the SMILE technology, according to the invention, is achieved as follows: after the completion of femto-laser formation of all parts of the lenticule (bottom of the lenticule, lateral cut of the lenticule, lenticular "cover"), except for the entrance cut of the lenticule, the “Visumax” femtolaser system detaches from the patient's eye. Next, an entrance cut is formed using a diamond knife used when performing a radial keratotomy. A distinctive feature of this knife is the ability to adjust the length of the blade, as well as the presence of a support part, which limits the entry of the blade deeper than a given value. The depth of the diamond blade is pre-set from 100 to 160 microns, which corresponds to the depth of the "cap" of the lenticule. The incision is formed in the lower quadrants of the cornea (right or left) above the edge of the projection of the "cover" of the lenticula, which is determined along the border of the vesicular layer. The blade of the knife is set strictly perpendicular to the surface of the cornea at the site of the future cut, after which the blade is inserted to a given depth of the cornea. Further, with a continuous movement, a cut with a length of 2-4 mm is made along an arc of a circle corresponding to the projection of the lenticule cover. As a result, it becomes possible to remove the lenticule and complete the operation.

The method is illustrated in FIG. 1-2. FIG. 1 shows the structural elements of the lenticulum in the sagittal section of the cornea. FIG. 2 shows the structural elements of the lenticula in the frontal section of the cornea. Positions designate: 1 - bottom of the lenticula, 2 - lateral incision of the lenticula, 3 - "cover" of the lenticula, 4 - inlet res of the lenticula.

The table shows the data of visual acuity, refraction and keratometry before and the next day after surgery.

The invention is illustrated by the following specific examples.

Example 1:

Patient V., 22 years old, applied 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: low distance vision in both eyes since childhood. Leads an active lifestyle, enjoys contact sports (volleyball). The patient was offered the SMILE keratorefractive surgery. The patient's preoperative data are presented in the table.

Operational data entered into the "VisuMax" OD femtolaser:

Built-in refraction: Sph: -4.00; Cyl: 0.00; Ah: 0.

Cover depth: 100 microns

Cap diameter: 7.5mm

Side cut angle 90 °

Lenticule diameter: 6.5mm

Lenticule thickness: 80 microns

Minimum lenticule thickness (edge): 15 microns

Entrance cut position 110 °

Input cut width 4 mm

Performing an operation:

After the treatment of the operating field, an eyelid expander was installed on the patient's right eye, then a vacuum ring was applied to the cornea of the same eye, followed by joining of the VisuMax femtolaser system within 25 seconds, the main structures of the lenticle were formed: the bottom of the lenticle, the lateral res of the lenticule, "cover »Lenticulum, except for the entrance cut of the lenticule, due to vacuum breakdown. Re-forming the entrance cut was impossible, since in the femtolaser system the operation was considered technically completed. Next, the diamond blade of the keratotomy knife was set to a depth of 120 µm, which corresponded to the depth of the "cover". It was decided to perform an incision in the upper right quadrant of the cornea over the projection of the edge of the "cap" of the lenticula, defined by the border of the vesicular layer. The blade of the knife was set strictly perpendicular to the surface of the cornea over the area of the future cut. Further, the knife was pressed until its limiting part touched the cornea, which ensured the entry of the blade to a given depth. Then, with a continuous movement, a 4 mm cut was made along an arc of a circle, corresponding to the projection of the edge of the lenticule cover. After the formation of the input cut, the lenticle was removed, the operation was completed successfully. The operation on the left eye was uneventful.

One day after the operation: the eye is calm, the cornea is transparent, the data of visual acuity and refraction are presented in the table. The patient is prescribed a standard treatment regimen after SMILE surgery.

Example 2:

Patient D., 26 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: low distance vision in both eyes since adolescence. At the initiative of the patient and the absence of contraindications, the SMILE keratorefractive surgery was chosen. The patient's preoperative data are presented in the table.

Operational data entered into the "VisuMax" OS femtolaser:

Built-in refraction: Sph: -3.75; Cyl: 0.00; Ah: 0.

Cover depth: 130 microns

Cap diameter: 7.5mm

Side cut angle 90 °

Lenticule diameter: 6.5mm

Lenticule thickness: 80 microns

Minimum lenticule thickness (edge): 15 microns

Entrance cut position 50 °

Input cut width 3 mm

During the operation, due to the breakdown of the vacuum, femtodissection on the left eye was interrupted at the stage of forming the entrance cut. Using a keratotomy knife with a blade set to a depth of 130 µm, an entrance incision was successfully formed in the upper left quadrant of the cornea as described in example 1. The operation was completed successfully. One day after the operation: the eye is calm, the cornea is transparent, the patient's data after the operation are presented in the table. The patient is prescribed a standard treatment regimen after SMILE surgery.

Example 3:

Patient A., 28 years old, applied 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: for the first time, low distance vision in both eyes was revealed during a medical examination upon admission to the institute. At the initiative of the patient and the absence of contraindications, the SMILE keratorefractive surgery was chosen. The patient's preoperative data are presented in the table.

Operational data entered into the "VisuMax" OD femtolaser:

The embedded refraction: Sph: -2.00; Cyl: 0.00; Ah: 0.

Cover depth: 160 microns

Cap diameter: 7.5mm

Side cut angle 90 °

Lenticule diameter: 6.5mm

Lenticule thickness: 80 microns

Minimum lenticule thickness (edge): 15 microns

Entrance cut position 120 °

Entrance cut width 2 mm

During the operation, the patient greatly averted his eyes, as a result of which a breakdown of the vacuum occurred and the femtodissection in the right eye was interrupted at the stage of the formation of the entrance incision. Using a keratotomy knife with a blade set to a depth of 160 µm, an entrance incision was successfully formed in the upper left quadrant of the cornea as described in example 1. The operation was completed successfully. One day after the operation: the eye is calm, the cornea is transparent, the patient's data after the operation are presented in the table. The patient is prescribed a standard treatment regimen after SMILE surgery.

Thus, on the example of the cases described above, the clinical possibility of a predictable and safe method of forming an entrance cut for removing the lenticule in the process of laser vision correction using the SMILE technology was demonstrated. The performed surgical actions allowed to safely complete the SMILE operation without resorting to the “Circle” program, while maintaining its valveless status, with all the ensuing advantages. The method of forming an entrance cut for removing the lenticule, in the process of laser vision correction using SMILE technology, is justified and possible to perform, which is confirmed by the first clinical results.

Claims (1)

A method of forming an entrance cut for removing a lenticule, in the process of laser vision correction using the technology of intrastromal removal of a lenticule, characterized in that after a femtolaser formation using a femtolaser system "VisuMax" the bottom of the lenticulum, a lateral cut of the lenticulum, the "cap" of the lenticule and an unformed entrance cut for removal lenticles, the femtolaser system is undocked from the patient's eye, then an entrance cut is formed using a diamond knife for radial keratotomy, preliminarily setting the blade depth from 100 to 160 microns, corresponding to the depth of the lenticule "cover", the cut is formed in the projection of the edge of the lenticular cover, which is determined by the boundary of the vesicular layer, when forming the cut, the knife blade is set perpendicular to the surface of the cornea, after which a cut 2-4 mm long is formed with a continuous movement along an arc of a circle corresponding to the projection of the lenticular cover.

Images