System for dissecting ocular tissue into elementary portions - Patent Application 20070122997

Abstract

The present invention relates to a dissection device comprising a femtosecond laser source for emitting a Gaussian laser beam, a shaping system for modulating the Gaussian laser beam, an optical scanner for moving the modulated laser beam, and an optical focusing system for focusing the modulated laser beam, characterized in that the processing device further comprises a control unit for controlling the femtosecond laser source, the shaping system, the optical scanner, and the optical focusing system to create first and second sets of vertical dissection planes (V1, V2) separated from each other by a horizontal dissection plane (H2), and the second set of vertical planes (V2) are laterally offset with respect to the first set of vertical planes (V1).

Description

[Technical Field]

[0001] The present invention relates to the field of surgery performed with femtosecond lasers, more particularly to the technical field of ophthalmic surgery, especially for the application of cutting the cornea or the lens.

[0002] The present invention relates to an apparatus for dissecting human or animal tissue, such as the cornea or lens, with a femtosecond laser source.

[0003] "Femtosecond laser source" means a light source capable of emitting a laser beam in the form of very short pulses, the duration of which is between 1 femtosecond and 100 picoseconds, preferably between 1 and 1000 femtoseconds, in particular around 100 femtoseconds. [Background technology]

[0004] As part of some surgical procedures, such as cataract surgery, it is desirable to break down tissue, such as the lens C, into smaller particles, such as cubes 108, to facilitate its extraction, for example, in the area of ​​the aspiration cannula CA, as shown in FIG.

[0005] To section the lens into a cube 108 that can be aspirated by an aspiration cannula, horizontal cuts 104a, 104b and vertical cuts 107 can be made as shown in Figure 2. The cuts are made by starting with the deepest horizontal cut 104a in the lens and stacking successive vertical cuts 107 and horizontal cuts 104b up to the most superficial horizontal cut in the lens.

[0006] Document WO2022 / 090408 describes, inter alia, a cutting device that allows the creation of horizontal and vertical cutting planes. - a femtosecond laser source for emitting a Gaussian laser beam in the form of pulses; - a shaping system arranged downstream of the laser source for modulating a phase of a wavefront of the Gaussian laser beam, the shaping system comprising a spatial light modulator (SLM) and configured to generate a modulated laser beam from the Gaussian laser beam; a sweeping optical scanner located downstream of the shaping system for moving the modulated laser beam; an optical focusing system downstream of the sweeping optical scanner for focusing the modulated laser beam at a focal plane of the dissection device and for moving the focal plane to a plurality of positions along an optical axis of propagation of the modulated laser beam; a control unit configured to drive the femtosecond laser source, the shaping system, the sweeping optical scanner, and the optical focusing system to create successive horizontal and vertical cut planes; Equipped with.

[0007] As shown in Figure 3, the operating principle of such a dissection device is as follows.

[0008] In the first step, the first horizontal incision 104a (i.e., the deepest) is made. - Applying a multi-point phase mask to the shaping system to generate a modulated multi-point laser beam that allows multiple impact points to be generated simultaneously; - Controlling the movement of the focusing system to align the focal plane of the dissection device with the desired initial dissection plane; - activating the femtosecond laser source, and - Driving the movement of a sweeping optical scanner along the optical path (e.g., in a crenellation).

[0009] A series of shots are performed in the focal plane of the cutting device. With each shot, several impact points, e.g., impact points forming a pattern, are simultaneously focused in the focal plane. Each impact point forms a bubble. An optical scanner allows the modulated multi-point laser beam, i.e., the pattern, to move in the focal plane between each shot. When the entire surface of the horizontal cutting plane is covered with bubbles, the first horizontal cutting plane 104a is completed.

[0010] In a second step, several adjacent vertical cuts 107a are made. For each vertical cut, the control unit: - applying a conical phase mask (i.e., which allows for the application of a linear phase modulation due to its rotational symmetry) to the shaping system to generate a modulated Bessel laser beam; - controlling the movement of the focusing system to focus the modulated laser beam to the desired depth; - activating a femtosecond laser source, and - Driving the movement of a sweeping optical scanner along an optical path (e.g., a segment).

[0011] A series of shots are performed. Each shot creates an impact line, which generates an elliptical bubble along the optical axis of propagation of the modulated laser beam. An optical scanner allows the modulated laser beam, and thus the impact line, to be moved between shots. If the depth of the impact line is less than the desired depth for the vertical dissection plane, the control unit 60 can monitor the optical focusing system 50 to change the depth of the dissection device's focal plane.

[0012] The vertical cut plane 107a is complete when the entire travel path is covered with an oval bubble.

[0013] The process of creating horizontal faces 104b, 104c, 104d and vertical faces 107b, 107c is repeated to create a stack of crystal cubes 108.

[0014] Once multiple bubbles have formed in various horizontal and vertical planes, the lens cube thus formed can be separated from the uncut portion of the tissue by using a tool to pull apart the tissue bridges that exist between the bubbles.

[0015] However, the formation of stacks of cubes 108 induces the accumulation of gas in the upper portions of the stack of faces, as shown in Figure 4. More specifically, as stacked cubes 108 form, gas bubbles 109 formed at depth in tissue 2 migrate towards the most superficial regions of the tissue.

[0016] This gas accumulation can rise above the plane of the laser incision into the tissue, for example, into the anterior chamber of the eye, when incising the lens. This can cause problems with the penetration of the laser beam into the tissue. In effect, the gas bubbles form an opaque bubble barrier that prevents the propagation of energy from the laser beam below, and thus the tissue incision in that area is located directly below this gas accumulation.

[0017] This gas accumulation can also cause deformation of the tissue during dissection, which can result in cubic dimensional defects that make its aspiration through the cannula difficult. Summary of the Invention [Problem to be solved by the invention]

[0018] One object of the present invention is to propose a device for cutting human or animal tissue that makes it possible to prevent the formation of gas accumulations that may hinder the propagation of laser beam energy underneath said gas accumulations.

[0019] More particularly, one object of the present invention is to propose an incision device that makes it possible to perform a complete incision of tissue, in particular of eye tissue such as the cornea or the lens, while avoiding masking of the laser beam during the incision.

[0020] Another object of the invention is to propose a device for dissecting human or animal tissue that makes it possible to form tissue cubes of more uniform size. [Means for solving the problem]

[0021] To this end, the invention provides a device for dissecting human or animal tissue, said device comprising a femtosecond laser source configured to emit a Gaussian laser beam in the form of pulses, and a device for processing the Gaussian laser beam, said processing device being arranged downstream of the femtosecond laser source, said processing device comprising: - a shaping system arranged on a trajectory of the Gaussian laser beam for modulating a phase of a wavefront of the Gaussian laser beam, the shaping system comprising a spatial light modulator and configured to generate a modulated laser beam from the Gaussian laser beam; a sweeping optical scanner positioned downstream of the shaping system for moving the modulated laser beam; an optical focusing system downstream of the shaping system for focusing the modulated laser beam at a focal plane of the lancing device and for moving the focal plane of the lancing device to a plurality of positions along an optical axis of propagation of the modulated laser beam; Equipped with The processing device further comprises a control unit for driving the femtosecond laser source, the shaping system, the sweeping optical scanner, and the optical focusing system to create successive horizontal and vertical section planes, the horizontal section planes extending perpendicular to the optical axis, and the vertical section planes extending parallel to the optical axis, and the control unit is configured to: - controlling the creation of the first horizontal incision plane; - controlling the creation of a first plurality of vertical incision planes above the first horizontal incision plane; - controlling the creation of a second horizontal incision plane above the first plurality of vertical incisions, wherein the first horizontal incision plane is deeper in the tissue than the second horizontal incision plane; - Controlling the creation of a second plurality of vertical planes above a second horizontal plane, wherein the second plurality of vertical cut planes are laterally offset (along at least one direction perpendicular to the optical axis) relative to the first plurality of vertical planes. It is configured as follows: The present invention proposes an incision device characterized by the above.

[0022] Within the framework of the present invention, "horizontal incision plane" means a plane located in the tissue to be treated and extending perpendicular to the optical axis of propagation of the laser beam emerging from the incision device.

[0023] Within the framework of the present invention, "vertical incision plane" means a plane located in the tissue to be treated and lying extending parallel to the optical axis of propagation of the laser beam emerging from the incision device.

[0024] Within the framework of the present invention, "impact point" means a point zone of the laser beam contained in the focal plane of the dissection device, where the intensity of the laser beam is sufficient to generate gas bubbles in the tissue.

[0025] Within the framework of the present invention, "impact line" means a linear zone of the laser beam extending perpendicular to the focal plane of the incision device (i.e., a segment of the laser beam extending parallel to the optical axis) when the intensity of the laser beam is sufficient to generate an elliptical bubble in the tissue.

[0026] Within the framework of the present invention, "adjacent collision points" means two collision points that are arranged opposite each other and are not separated by another collision point.

[0027] "Close collision points" means two collision points in a group of adjacent points that have the smallest distance.

[0028] Within the framework of the present invention, a "pattern" means a number of simultaneously generated laser impact points.

[0029] The invention thus makes it possible to create groups of vertical incisions separated by horizontal incisions to form elementary cubes of tissue that can be aspirated by a suction cannula, each group of vertical incisions advantageously being laterally offset with respect to the group of vertical incisions adjacent to it.

[0030] Specifically, each group is defined by a number of vertical sections formed between two horizontal sections. Three overlapping horizontal sections, i.e., - deep horizontal incision, - the middle horizontal incision plane, and - horizontal cut of the surface When arranged in tissue, Two groups of vertical incisions are formed between these horizontal incisions: - the first group of vertical incisions is formed between the deep horizontal incision and the middle horizontal incision, A second group of vertical planes is formed between the medial and superficial incision planes, the vertical planes of the second group being laterally offset relative to the vertical planes of the first group.

[0031] As will be apparent from the following description, this lateral offset between adjacent groups of vertical cut surfaces makes it possible to prevent gas contained in bubbles formed in one group of vertical cut surfaces from propagating in the direction of bubbles formed in an adjacent group of vertical cut surfaces that are more superficial.

[0032] Optical phase modulation is achieved by using a phase mask. The energy of the incident laser beam is maintained after modulation, and beam shaping is achieved by acting on its wavefront. The phase of an electromagnetic wave describes the instantaneous state of its amplitude. Phase depends on both time and space. In the case of spatial shaping of a laser beam, only the spatial variation of the phase is considered.

[0033] A wavefront is defined as the surface of points of a beam that have equal phase (i.e., points that have equal travel times from the laser source that emits the beam). Therefore, modifying the spatial phase of a beam involves modifying its wavefront.

[0034] Within the framework of the present invention, the phase modulation of the wavefront can be - only a few impingement points in the incision plane (used to form horizontal incisions); in this case, the modulated laser beam is unique throughout its propagation path, and the phase modulation of the wavefront allows the phase of various points on the surface of the beam to be delayed or advanced relative to the initial wavefront, so that each of these impingement points creates constructive interference at N different points in the focal plane of the lens, and the redistribution (partitioning) of energy to multiple impingement points occurs only in a single plane (i.e., the focal plane), and not throughout the entire propagation path of the modulated laser beam; - Or, a line of impact perpendicular to the focal plane of the dissection device (used to form a perpendicular dissection plane) This allows for the generation of a single modulated laser beam that forms either

[0035] Preferred, non-limiting aspects of the lancing device are as follows: - the second plurality of perpendicular cutting planes may be laterally offset (displaced) relative to the first plurality of perpendicular cutting planes by a distance of between 5 μm and 500 μm; - the second plurality of perpendicular cutting planes may be laterally offset (displaced) relative to the first plurality of perpendicular cutting planes along first and second axes perpendicular to the optical axis, the first and second axes being orthogonal to one another; - The control unit controls the following for each horizontal incision: applying a multi-point phase mask to the shaping system to generate a single modulated multi-point laser beam, the multi-point phase mask being calculated to distribute (distribute) the energy of the modulated multi-point laser beam to at least two impingement points in the focal plane of the dissection device; Controlling the movement of the focusing system to match the focal plane of the dissection device with the desired depth for the horizontal dissection plane; driving a sweeping optical scanner to move an impingement point of the single modulated multi-point laser beam along a first path of movement; Activate the femtosecond laser source It may be configured as follows: the control unit, for generating each vertical incision plane of the first plurality of vertical incision planes, applying an axicon modulation setpoint to a shaping system to generate a modulated Bessel-type laser beam from a Gaussian laser beam, where the modulation setpoint includes a phase mask that emulates an axicon applied to a spatial light modulator, and the modulated Bessel-type laser beam creates an impingement line that allows for the generation of an elliptical gas bubble in tissue; Activating a sweeping optical scanner to move the impingement line of the modulated Bessel-type laser beam along a second optical translation path to form a set of adjacent elliptical bubbles. It may be configured as follows: the control unit controls, for generating each vertical incision plane of the second plurality of vertical incision planes, Applying an axicon modulation setpoint to the shaping system Driving a sweeping optical scanner to move the impingement line of the modulated Bessel laser beam along a third optical path that is laterally offset relative to the second optical path. It is configured as follows: - each vertical section is made up of a stack of several sets of adjacent oval bubbles, and the control unit (60) o driving an optical focusing system to position a focal plane of the cutting device at a predetermined non-zero distance from the first horizontal cutting plane, the predetermined distance being less than a length of the impingement line of the modulated Bessel-type laser beam such that the impingement line partially intersects the first horizontal cutting plane; driving a sweeping optical scanner to move an impingement line of the modulated Bessel-type laser beam to form a first set of adjacent elliptical bubbles; driving the optical focusing system to position the focal plane of the lancing device at a predetermined distance from the first set of adjacent elliptical bubbles such that the impingement line partially intersects with the first set of adjacent elliptical bubbles; Activating a sweeping optical scanner to move the impingement line of the modulated Bessel-type laser beam to form a second set of adjacent elliptical bubbles. It is configured as follows: The predetermined distance may be 1 / 5 to 1 / 3 of the length of the collision line.

[0036] The present invention also provides a method for dissecting tissue, for example previously collected human or animal tissue, with a dissection device, the dissection device comprising: - a femtosecond laser source configured to emit a Gaussian laser beam in the form of pulses; - a shaping system downstream of the femtosecond laser source, arranged on a trajectory of the Gaussian laser beam, for modulating a phase of a wavefront of the Gaussian laser beam, the shaping system comprising a spatial light modulator and configured to generate a modulated laser beam from the Gaussian laser beam; a sweeping optical scanner positioned downstream of the shaping system for moving the modulated laser beam; an optical focusing system downstream of the shaping system for focusing the modulated laser beam at a focal plane of the lancing device and for moving the focal plane of the lancing device to a plurality of positions along an optical axis of propagation of the modulated laser beam; Equipped with The incision method includes the step of creating successive horizontal and vertical incision planes by driving a femtosecond laser source, a shaping system, a sweeping optical scanner, and an optical focusing system, wherein the horizontal incision planes extend perpendicular to an optical axis, and the vertical incision planes extend parallel to the optical axis, and the creating step includes: - forming a first horizontal incision; - forming a first plurality of vertical incisions on the first horizontal incision; - forming a second horizontal incision plane above the first plurality of vertical incisions, the first horizontal incision plane being deeper in the tissue than the second horizontal incision plane; - forming a second plurality of vertical surfaces on the second horizontal surface that are laterally offset relative to the first plurality of vertical surfaces. The present invention relates to a method comprising the steps of:

[0037] Preferred, but non-limiting, aspects of the method according to the present invention are as follows: - the second plurality of perpendicular cutting planes may be laterally offset (displaced) relative to the first plurality of perpendicular cutting planes by a distance of between 5 μm and 500 μm; - the second plurality of perpendicular cutting planes may be laterally offset relative to the first plurality of perpendicular cutting planes along first and second axes perpendicular to the optical axis, the first and second axes being orthogonal to each other; Each step of forming a horizontal incision comprises the following sub-steps: the sub-step of applying a multi-point phase mask to the shaping system to generate a single modulated multi-point laser beam, the multi-point phase mask being calculated (intended) to distribute (distribute) the energy of the modulated multi-point laser beam to at least two impingement points in the focal plane of the dissection device; the sub-step of moving the focal plane of the dissection device to the desired depth relative to the horizontal dissection plane using a focus adjustment system; using a sweeping optical scanner to move the impact point of the single modulated multi-point laser beam along a first path of movement; the substep of emitting a Gaussian laser beam by a femtosecond laser source. may contain; - forming each vertical cut surface of the first plurality of vertical cut surfaces includes the following sub-steps: applying an axicon modulation setpoint to a shaping system to generate a modulated Bessel-type laser beam, the modulation setpoint including a phase mask emulating an axicon applied to a spatial light modulator, the phase mask having rotational symmetry around a center point of symmetry, the grayscale of each point of the phase mask varying as a function of the distance between each point and the center point of symmetry, the modulated Bessel-type laser beam creating an impingement line that allows generating an elliptical gas bubble in tissue; using a sweeping optical scanner to move the line of impingement of the modulated Bessel-type laser beam along a second optical translation path to form a set of adjacent elliptical bubbles; may contain; - forming each vertical cut surface of the second plurality of vertical cut surfaces includes the following sub-steps: applying an axicon modulation setpoint to the shaping system; using a sweeping optical scanner to move the line of impingement of the modulated Bessel-type laser beam along a third optical path that is laterally offset relative to the second optical path; may contain; Each vertical cut surface may be composed of a stack of several sets of adjacent oval bubbles, and each step of forming the vertical cut surface may include the following sub-steps: the substep of moving, using an optical focusing system, the focal plane of the cutting device a predetermined non-zero distance from the first horizontal cutting plane, the predetermined distance being less than the length of the impingement line of the modulated Bessel-type laser beam such that the impingement line partially intersects the first horizontal cutting plane; using a sweeping optical scanner to move the line of impingement of the modulated Bessel-type laser beam to form a first set of adjacent elliptical bubbles; using an optical focusing system to move the focal plane of the lancing device a predetermined distance from the first set of adjacent elliptical bubbles so that the impingement line partially intersects with the first set of adjacent elliptical bubbles; using a sweeping optical scanner to move the line of impingement of the modulated Bessel-type laser beam to form a second set of adjacent elliptical bubbles. may contain; The predetermined distance may be 1 / 5 to 1 / 3 of the length of the collision line.

[0038] Other characteristics and advantages of the present invention will become apparent from the following description, given for information and without limitation, with reference to the attached drawings, in which: [Brief explanation of the drawings]

[0039] [Figure 1] 1 is a schematic diagram of a patient's eye. [Figure 2] 1 is a schematic diagram of bubbles created to form elementary tissue cubes from horizontal and vertical cut planes. FIG. [Figure 3] FIG. 1 is a schematic diagram of a stack of horizontal and vertical cut planes obtained using the cutting device described in document WO2016 / 055539. [Figure 4] FIG. 1 is a schematic diagram showing the accumulation of gas after overlapping perpendicular cuts have been made using the cutting device described in document WO2016 / 055539. [Figure 5] 1 is a schematic diagram of a dissection device according to the present invention; [Figure 6] FIG. 1 is a schematic diagram illustrating the focusing of a Bessel-type non-diffracting beam. [Figure 7a] 1 is an image of a first phase mask that makes it possible to emulate the behavior of a negative axicon in the SLM of a dissection device according to the invention; [Figure 7b]10 is an image of a second phase mask that makes it possible to emulate the behavior of a positive axicon in the SLM of a dissection device according to the invention. [Figure 8] FIG. 1 is a diagram of a partial implementation of a lancing device. [Figure 9] FIG. 1 is a schematic diagram of a Bessel beam. [Figure 10] FIG. 1 is a schematic diagram of the control steps during the creation of a horizontal incision plane. [Figure 11] FIG. 1 is a schematic diagram of the control steps during the creation of a vertical incision plane. [Figure 12] FIG. 1 is a schematic diagram illustrating the formation of vertical cut planes from a Bessel laser beam. [Figure 13] FIG. 10 is a schematic diagram showing a set of impingement lines used to create stacked elliptical bubble sections. [Figure 14] FIG. 1 is a schematic diagram of the control steps during the creation of successive horizontal and vertical cut planes. [Figure 15] FIG. 1 is a schematic diagram of successively created horizontal and vertical sections. DETAILED DESCRIPTION OF THE INVENTION

[0040] The present invention relates to a system for dissecting human tissue with a femtosecond laser. In the remainder of this document, the invention will be described with reference to the example of dissecting the lens of a human or animal eye.

[0041] 1. cutting device 5, one embodiment of a dissection device according to the present invention is shown, which can be placed between a femtosecond laser source 10 and a target 2 to be treated.

[0042] The femtosecond laser source 10 is capable of emitting a Gaussian laser beam in the form of pulses. For example, the femtosecond laser source 10 emits light having a wavelength of 1,030 nm in the form of 400 femtosecond pulses. The femtosecond laser source 10 has a power of 20 W and a frequency of 500 kHz.

[0043] The target 2 is, for example, human or animal tissue to be dissected, such as the cornea or lens.

[0044] The incision device is a shaping system 30 arranged on the trajectory of the laser beam 110 originating from the femtosecond laser 10; a sweeping optical scanner 40 downstream of the forming system 30; an optical focusing system 50 downstream of the sweeping optical scanner 40; - control unit 60 and Equipped with.

[0045] The shaping system 30 makes it possible to modulate the phase of the laser beam 110 coming from the femtosecond laser source 10. This shaping system 30 is advantageously a programmable component.

[0046] The sweeping optical scanner 40 allows the phase-modulated laser beam 310 from the shaping system 30 to be directed to move the incision pattern along a user-predetermined movement path in the focal plane 101 of the incision system.

[0047] The optical focusing system 50 makes it possible to move the focal plane 101 - which corresponds to the plane of incision - of the modulated and deflected laser beam 410 .

[0048] A control unit 60 makes it possible to drive the shaping system 30 , the sweeping optical scanner 40 and the optical focusing system 50 .

[0049] The cutting device is adapted to form horizontal and vertical cutting planes. Depending on the type of cutting plane desired (vertical or horizontal), the control unit 60 - configuring the shaping system to modulate the laser beam 110 according to the desired appearance of the impact point / impact line; - Monitoring the sweeping optical scanner 40 and optical focusing system 50 to generate the desired dissection plane.

[0050] As will be explained in more detail below, the present inventors have developed a unique solution for configuring a cutting device for the creation of vertical cutting planes.

[0051] 2. Elements of the incision device 2.1. Molding System The laser beam spatial shaping system 30 includes: - due to the impact point of the modulated laser beam in the case of the formation of horizontal incisions, or - due to the impingement line of the modulated laser beam in the case of the formation of a vertical incision plane This allows the wavefront of the laser beam 110 to be modified according to the desired shape.

[0052] The shaping system 30 preferably comprises a spatial light modulator, also known as an SLM.

[0053] The SLM allows for modulation of the final energy distribution of the laser beam 110 generated by the laser source 10. It is a device consisting of a layer of liquid crystals with a monitored orientation that allows for dynamic shaping of the wavefront and thus the phase of the laser beam 110. The liquid crystal layer of the SLM is organized as a grid (or matrix) of pixels. The optimal thickness of each pixel is electrically monitored by the orientation of the liquid crystal molecules belonging to the surface corresponding to the pixel. The SLM uses the principle of liquid crystal anisotropy, i.e., the modification of the index of the liquid crystals depending on their spatial orientation. The orientation of the liquid crystals can be achieved using an electric field. The modification of the index of the liquid crystals therefore modifies the wavefront of the laser beam.

[0054] In a known manner, the SLM executes a phase mask, i.e., a map that determines how (to what extent) the phase of the laser beam 110 needs to be modified to obtain a given amplitude distribution. The phase mask is a two-dimensional image, each point of which is associated with a respective pixel of the SLM. This phase mask allows driving the index of each liquid crystal of the SLM by converting the value associated with each point of the mask—for example, a value expressed in a grayscale from 0 to 255 (hence, black to white)—to a contrast value, for example, a contrast value expressed in a phase from 0 to 2π. The phase mask is thus a modulation setpoint displayed on the SLM that, upon reflection, causes an unequal spatial phase shift of the laser beam 110 illuminating the SLM. Of course, those skilled in the art will understand that the grayscale range may vary depending on the SLM model used. For example, in some cases, the grayscale range may be 0 to 220.

[0055] Various phase masks can be created depending on the type of cut plane the user wishes to create, i.e. - vertical cutting plane, -or horizontal incision plane, either Depending on the application, this may be applied to the SLM.

[0056] To create the vertical cut plane, the phase mask used (hereafter referred to as a "conical phase mask") allows for the application of a linear phase modulation with rotational symmetry. A modulated Bessel-type laser beam is thus obtained.

[0057] To create the horizontal dissection plane, a phase mask (hereinafter referred to as a "multipoint phase mask") is used, which allows the application of phase modulation to distribute the laser beam energy to at least two impact points that form a pattern in the focal plane of the dissection system. A modulated multipoint laser beam is thus obtained.

[0058] 2.1.1. vertical cutting plane For cutting vertical planes, we propose to modulate the phase of the laser beam 110 coming from the femtosecond laser source 10 downstream of the shaping system 30 to generate a modulated Bessel-type laser beam 310.

[0059] Bessel beams are called "non-diffracting" beams because they have the property of maintaining a constant profile along the optical axis of propagation of the laser beam (hereinafter referred to as the "optical axis"), unlike the behavior of a Gaussian laser beam (e.g., laser beam 110 produced from femtosecond laser source 10), which diverges when focused.

[0060] 2.1.1.1. Bessel beam A perfect zero-order Bessel beam can be mathematically defined as a beam whose electric field is formally described by the zero-order Bessel function of the first kind, J: E(r, Φ, z)A0J0(k r r)e jk z z . where: - A0 is the amplitude of the electric field, -k z and k r are the longitudinal and radial wave vectors, - z, r and Φ are the longitudinal, radial and azimuthal components.

[0061] As shown in FIG. 6, the formation of a Bessel beam 313 results from the interference of plane waves whose wave vectors form a conical surface.

[0062] In theory, the lateral extension of the annular structure is infinite, as is the non-diffracting propagation distance.

[0063] In practice, experimental Bessel beams have a finite non-diffracting propagation distance Z along the optical axis due to the finite propagation and limited amount of energy observed in optics. B This finite non-diffracting propagation distance Z B defines the non-diffracting zone ZND.

[0064] Z B >>Z R It is assumed that Z R is the Rayleigh distance of a normal Gaussian beam of similar transverse size. In other words, the depth of each impact point of a Bessel beam (i.e., the dimension along the distance parallel to the optical axis of propagation of the laser beam) is much greater than the depth of each impact point of a Gaussian laser beam (e.g., a laser beam produced by a femtosecond laser source).

[0065] Therefore, the use of Bessel beams allows for much greater tissue depths to be dissected than with Gaussian beams. Specifically, a single impingement line of a Bessel beam can dissect tissue to a depth equivalent to that of four overlapping Gaussian beam impingement points. Moving the Bessel beam's impingement line using a sweeping optical scanner allows for a perfectly vertical dissection plane to be generated four times faster than with Gaussian beam impingement points.

[0066] Due to this specific formation based on a conical wavefront, the Bessel beam has excellent self-regenerating properties, which means that the beam can regenerate itself within the non-diffracting zone ZND after any obstruction in its path, ensuring the formation of an extended bubble with each shot of the laser source 10, even when part of the modulated laser beam 310 is masked by an obstruction, thereby ensuring the quality of the incision in the vertical plane.

[0067] 2.1.1.2. Conical phase mask for forming a modulated Bessel-type laser beam. There are various techniques for generating Bessel beams from Gaussian laser beams, which generally involve axicon phase modulation.

[0068] Specifically, Bessel beams can be obtained by using conical lenses known as "axicons," which can be concave / dimpled (called "negative axicons") or convex / ridged (called "positive axicons").

[0069] To avoid the use of optical / mechanical elements, we propose using a shaping system 30 equipped with an SLM to generate Bessel beams. For this purpose, a conical phase mask (making it possible to emulate an axicon) is applied to the SLM by the control unit 60. The SLM then enables conical phase modulation of the Gaussian laser beam 110 originating from the femtosecond laser source 10. Thus, by using the same SLM, it is possible to create multi-point horizontal incisions and then vertical incisions in the Bessel beam modality without changing optical elements, thus significantly reducing the surgical time from 30 seconds to 1 minute, making it suitable for application to a patient's eye in less than 3 minutes.

[0070] A conical phase mask applied to the SLM of the shaping system to form a modulated Bessel laser beam - Partitioning algorithms (Vellekoop and Mosk, 2008), - or by using any other algorithm known to those skilled in the art It can be calculated (calculated and created).

[0071] Two examples of such phase masks are shown in Figures 7a and 7b. When one of the first and second phase masks is applied to an SLM, the SLM can imprint the phase profile of the axicon on the input Gaussian laser beam 110 to obtain a modulated Bessel-type laser beam 310 at the output of the shaping system 30.

[0072] As shown in Figure 7a, a first conical phase mask (referred to as 314) allows the behavior of a negative axicon (i.e., a concave axicon) to be emulated. As shown in Figure 7b, a second conical phase mask (referred to as 315) allows the behavior of a positive axicon (i.e., a convex axicon) to be emulated. These first and second phase masks each have rotational symmetry around a central point of symmetry, and the grayscale of each pixel varies as a function of the distance between each pixel and the central point of symmetry.

[0073] 7a and 7b are applied to the SLM, the shaping system 30 makes it possible to form a modulated Bessel-type laser beam 310 (at the output of the shaping system 30) from a Gaussian laser beam 110 arising (at the input of the shaping system 30) from the femtosecond laser source 10. A modulated laser beam with a spatial intensity distribution in a Bessel beam is thus obtained.

[0074] 2.1.1.3. Implementation of a dissection device as part of tissue dissection from a modulated Bessel-type laser beam FIG. 8 shows a schematic diagram of the dissection device. This schematic diagram is partial in that it does not show the femtosecond laser source and the sweeping optical scanner. Furthermore, in FIG. 8, the optical focusing system 50 (as a whole) is represented by an equivalent lens 51, and those skilled in the art will understand that the optical focusing system 50 does not consist solely of a fixed lens.

[0075] 8, a Bessel beam 313 is formed immediately after the conical phase modulation surface, i.e., immediately after the SLM of the shaping system 30. The SLM simulates a conical lens (negative or positive axicon), and the central spot of maximum intensity of the Bessel beam is formed in the image focal plane 32 of the SLM.

[0076] The equivalent lens 51 of the optical focusing system 50 is positioned downstream of the shaping system 30 and is arranged so that the object focal plane 52 of the equivalent lens extends at a non-zero distance along the optical axis from the image focal plane 32 of the shaping system 30.

[0077] Therefore, the objective focal plane 52 of the equivalent lens 51 of the optical focusing system 50 extends out of the non-diffracting zone ZND of the Bessel beam, resulting in the impingement line shown in Figure 9 at the output of the dissection system. More specifically, the Bessel beam: - a vessel ring 33a focused in the image focal plane 53 of the equivalent lens 51 (corresponding to the focal plane of the dissection device); - a line 33b of the collection of rays of the Bessel beam corresponding to the image of the non-diffracting zone ZND (the line 33b forms outside the image focal plane 53 of the equivalent lens 51); It consists of:

[0078] Within the framework of the present invention, it is line 33b that constitutes the collision line used to create the vertical cut plane (the energy contained in the vessel ring is not sufficient to form a bubble).

[0079] The lines 33b can be formed either before or after the ring 33a depending on the sign of the phase modulation, in other words, the position of the lines 33b relative to the ring 33a depends on the type of axicon (positive or negative) emulated using a conical phase mask.

[0080] The Bessel non-diffracting zone ZND (i.e., line 33b) is moved out of the focal plane of the dissection system so that no interference occurs with unmodulated light, allowing for better monitoring of the intensity profile without the energy losses associated with filtering the beam.

[0081] 2.1.2. horizontal cutting plane For cutting horizontal planes, we propose to modulate the phase of the laser beam 110 coming from the femtosecond laser source 10 downstream of the shaping system 30 to generate a modulated multi-spot laser beam.

[0082] For this purpose, a multipoint phase mask is calculated which is applied to the SLM to obtain a modulated multipoint laser beam. - iterative algorithms based on the Fourier transform, for example IFTA (Iterative Fourier Transform Algorithm) type algorithms, or - Various optimization algorithms, such as genetic algorithms or simulated annealing It is calculated by:

[0083] This multi-point phase mask is calculated to create intensity peaks in the focal plane of the dissector, each intensity peak generating a respective impingement point in the focal plane of the dissector.

[0084] More specifically, the multi-point phase mask is calculated to, for example, form a pattern in the focal plane of the dissection device to distribute (distribute) the energy of the laser beam generated by the laser source to multiple impingement points. This wavefront modulation can be considered a two-dimensional interference phenomenon. Each portion of the initial laser beam generated by the laser source is delayed or advanced relative to the initial wavefront so that each of these portions is redirected to create constructive interference at N different points in the focal plane of the lens. This redistribution (distribution) of energy to multiple impingement points occurs only within a single plane (i.e., the focal plane) and not along the entire propagation path of the modulated laser beam. Therefore, the resulting multi-point laser beam (at the output of the shaping system 30) is unique: since this phenomenon can be likened to constructive interference (which occurs only in one plane and not throughout the entire propagation, as in the case of the separation of an initial laser beam into multiple secondary laser beams), observing the modulated laser beam before or after the focal plane of the dissection device (which corresponds to the focal plane of the optical focusing system 50) does not allow one to identify the redistribution (partition) of energy to multiple separate impact points.

[0085] Having a single modulated multi-point laser beam facilitates the integration of a sweeping system, such as an optical scanner, for moving multiple impingement points in the focal plane. Indeed, the input diameter of the sweeping system is of the order of the diameter of the initial laser beam originating from the laser source 10, and the use of a single modulated multi-point laser beam (whose diameter is substantially equal to that of the initial laser beam) limits the risk of aberrations that may occur due to beam segmentation techniques such as those described in document US2010 / 0133246.

[0086] The shaping system 30 thus allows for distributing its energy by phase modulation from a single laser beam (single beam upstream and downstream of the SLM) that is shaped by phase modulation from a Gaussian laser beam that generates a single impact point by a multipoint phase mask applied to the SLM, to generate several impact points simultaneously in the focal plane of the dissection device, which allows for a reduction in the time required to create a horizontal dissection plane.

[0087] For example, in the case of a modulated multi-point laser beam with three impact points, the time required to create a horizontal incision plane is reduced by a factor of six (compared to creating the same horizontal incision plane using a Gaussian laser beam that generates a single impact point).Those skilled in the art know how to calculate the values ​​at each point of a multi-point phase mask to distribute (distribute) the energy of the laser beam to different impact points in the focal plane of the incision device.

[0088] 2.2. Sweeping Optical Scanner The sweeping optical scanner 40 - for the creation of a horizontal incision plane, the impact point is positioned along the first path of movement, - Position the impact line along the second path of travel to create a vertical incision plane. To move, the modulated (Bessel or multi-point) laser beam 310 can be deflected.

[0089] The sweeping optical scanner 40 an input orifice for receiving the phase-modulated laser beam 31 emerging from the shaping unit 30; - one (or more) optical mirrors pivoting about at least two axes for deflecting the phase-modulated laser beam 310; an output orifice for transmitting the modulated laser beam 410 deflected in the direction of the optical focusing system 50; Equipped with.

[0090] The optical scanner 40 used is, for example, the sweeping head IntelliScan III manufactured by SCANLAB AG.

[0091] The input and output orifices of such an optical scanner 40 have a diameter of approximately 10-20 millimeters, and the achievable sweeping speed is approximately 1 m / s to 10 m / s.

[0092] The mirror is connected to one or more motors to enable it to pivot, the motors for the mirror pivoting being advantageously driven by a control unit 60, the details of which are explained below.

[0093] The control unit 60 - collision points along the first path of movement, - Collision line along the second movement path The scanning optical scanner 40 is programmed to move the scanning optical scanner 40.

[0094] In the case of a horizontal cutting plane, the first path of movement comprises a plurality of cutting segments. The first path of movement may advantageously have a crenellated shape.

[0095] In the case of a vertical section, the second movement path includes one segment. The control unit 60 may be configured to instruct the optical scanner 40 to move the vessel impingement line rearward and forward along the segment to cut the vertical section throughout its depth. For example, if the optical scanner 40 starts with a segment from the left, the optical scanner starts with this segment from the rear right, then from the left, then from the right, etc., throughout the height of the vertical section.

[0096] The sweeping of the beam has an influence on the result of the incision obtained: in fact, the sweeping speed and sweeping pitch used are parameters that influence the quality of the incision.

[0097] Advantageously, the control unit 60 can be programmed to activate the femtosecond laser 10 when the sweeping speed of the optical scanner 40 is higher than a threshold value. This makes it possible to synchronize the emission of the laser beam 110 with the sweeping of the sweeping optical scanner 40. More specifically, the control unit 60 activates the femtosecond laser 10 when the pivoting speed of the mirror of the optical scanner 40 is constant. This makes it possible to improve the quality of the incision by performing uniform surface modeling of the incision surface.

[0098] 2.3. Optical Focusing System The optical focusing system 50 allows the focal plane of the dissection device to be moved depending on the type of dissection to be made.

[0099] The optical focusing system 50 includes: an input orifice for receiving the phase-modulated and deflected laser beam originating from the sweeping optical scanner 40; - one (or more) motorized lenses enabling translation of the modulated and deflected laser beam along its optical path; an output orifice for directing the focused laser beam toward the tissue to be treated; Equipped with.

[0100] The control unit 60 is programmed to drive the movement of the lenses of the optical focusing system 50 to move the focal plane of the lancing device depending on the type of lancing plane to be made.

[0101] In the case of a horizontal dissection plane, the dissection plane corresponds to the focal plane of the dissection device. The control unit 60 drives the movement of the lenses of the optical focusing system 50 to focus the modulated and deflected laser beam 410 to the desired depth corresponding to the depth of the dissection plane to be made.

[0102] In the case of a vertical incision plane, the incision plane is: - below the focal plane of the dissection device (the Vessel ring 33a is located above the collision line used to perform the dissection), if the conical phase mask used allows the SLM to emulate a positive axicon; - above the focal plane of the dissection device (the Vessel ring 33a is located below the collision line used to perform the dissection), if the conical phase mask used allows the SLM to emulate a negative axicon It may be located at.

[0103] Preferably, the distance between two consecutive cut surfaces is between 2 μm and 500 μm, in particular - spacing of 2 to 20 μm, preferably 5 to 10 μm, for treating volumes requiring high precision, for example in refractive surgery, or - high precision is not required, for example, to treat a volume to destroy the central part of the lens nucleus, with a spacing of 20 to 500 μm, preferably 50 to 300 μm; is.

[0104] Of course, this distance may vary within the volume comprised by the stack of cutting planes.

[0105] 2.4. Control Unit As previously indicated, the control unit 60 allows monitoring the various components of the dissection device, namely the femtosecond laser source 10, the shaping system 30, the sweeping optical scanner 40 and the optical focusing system 50.

[0106] The control unit 60 controls these various components: - Transmission of control signals, e.g. transmitting an activation signal to a femtosecond laser source 10; Transfer of the phase mask to the shaping system 30, Transmission of the sweeping speed to the sweeping optical scanner 40; Transmission of the position of the sweeping optical scanner 40 along the path of movement, Transmission of the incision depth to the optical focusing system 50, - Various elements of the system, e.g. the sweeping speed reached by the optical scanner, or - Position of the optical focusing system, etc. Receipt of measurement data resulting from are connected via one (or more) communication buses that allow

[0107] Control unit 60 may consist of one or more workstations and / or one or more computers, or any other type known to those skilled in the art. Control unit 60 may include, for example, a mobile phone, a tablet computer (e.g., an iPad), a personal digital assistant (PDA), etc.

[0108] In all cases, the control unit 60 includes a processor programmed to enable it to drive the femtosecond laser source 10, the shaping system 30, the sweeping optical scanner 40, the optical focusing system 50, etc.

[0109] Advantageously, the control unit 60 is programmed to vary the shape of the modulated laser beam between two consecutive cutting planes, in particular between a horizontal cutting plane and a vertical cutting plane.

[0110] 2.5. Operating principle The operating principle of the incision device according to the present invention is as follows: - operation of the device to create a horizontal incision plane; - operation of the device to create a vertical incision plane; - Operation of the device to create a superposition of stacked horizontal and vertical cut surfaces This will be described in more detail by elaborating on the following.

[0111] 2.5.1. Horizontal incision Within the framework of the present invention, the formation of the horizontal cutting plane is carried out as follows.

[0112] As shown in FIG. 10, the control unit 60 generates control signals to the optical focusing system 50 to drive the movement of the focal plane of the lancing device to coincide with the desired horizontal lancing plane (step E110).

[0113] The control unit 60 sends the multi-point phase mask to the shaping system 30 to generate a modulated multi-point laser beam (step E120).

[0114] The control unit 60 also activates the movement of the sweeping optical scanner 40 to the initial position of the first sweeping optical path. Because the sweeping is performed in X and Y, the scanner includes one or more mirrors. For example, in the embodiment shown in FIG. 5, the sweeping optical scanner 40 includes a first mirror X and a second mirror Y, the pivoting of which allows the modulated laser beam to move along the first path of movement. Alternatively, the scanner may include a single mirror configured to pivot about two separate axes.

[0115] the focusing system 50 and the optical scanner 40 are in place (i.e. the scanner has already reached the start line position of the target); - a multi-point phase mask is loaded into the shaping system 30; The rotation speed of the mirror of the optical scanner 40 is constant. If so, the control unit 60 activates the femtosecond laser source 10 to generate a laser pulse (step E130).

[0116] A femtosecond laser source 10 generates a laser beam 110 that passes through a shaping system 30. The shaping system 30 modulates the phase of the laser beam to generate a single modulated multi-point laser beam.

[0117] The modulated multi-point laser beam 310 exits the shaping system 30 and enters an optical scanner 40 which deflects the modulated multi-point laser beam 310 .

[0118] The modulated and deflected laser beam 410 enters an optical focusing system 50 that focuses the beam at the focal plane of the dissection device. At the focal plane, a modulation setpoint (i.e., a multi-point phase mask) applied to the shaping system 30 allows the energy to be distributed (distributed) to multiple impact points. This multiple, simultaneously generated impact points form a pattern. Each impact point of the pattern simultaneously generates a gas bubble.

[0119] The femtosecond laser 10 continues to emit other pulses in the form of a laser beam at a determined rate, and between each pulse the mirror pivots by a certain angle, which results in the movement of the pattern 8 and the creation of a new bubble offset relative to the previous bubble along the first optical path (step E140).

[0120] The actuation of the femtosecond laser source 10 and the sweeping optical scanner 40 is repeated to form horizontal sections.

[0121] By varying the speed of movement of the mirror and / or the rate at which pulses are generated by the femtosecond laser source 10, it is possible to vary the distance between two successive patterns.

[0122] Once the incision line is completed, the control unit 60 deactivates the femtosecond laser source 10 and controls the movement of the optical scanner 40 to the next incision position according to the first movement path.

[0123] Once the optical scanner 40 is in place and the mirror has reached its constant setpoint speed, the control unit 60 reactivates the femtosecond laser source 10. The laser beam 110 passes through the shaping system 30, the optical scanner 40, and the optical focusing system 50. A new line of bubbles parallel to the previous line is formed at the cut surface.

[0124] Once the optical scanner 40 has swept through all positions in the first path of travel, the horizontal section plane is complete.

[0125] In summary, to create a horizontal cutting plane, the control unit 60: - applying a multi-point phase mask to the shaping system 30 to generate a single modulated multi-point laser beam, the multi-point phase mask being calculated to distribute (distribute) the energy of the modulated multi-point laser beam to at least two impingement points in the focal plane of the dissection device; - controlling the movement of the focus adjustment system 50 to match the focal plane of the dissection device with the desired depth for the horizontal dissection plane; - driving the sweeping optical scanner 40 to move the impingement point of the single modulated multi-point laser beam along a first path of movement; - Activate the femtosecond laser source 10 (after the scanner movement speed has stabilized) It is structured as follows.

[0126] 2.5.2. Creation of a vertical incision Within the framework of the present invention, the formation of the vertical cut planes is carried out as follows.

[0127] 11, the control unit 60 generates control signals to the optical focusing system 50 to drive the movement of the focal plane of the dissection device to position it at a given depth relative to the desired position for the vertical dissection plane (step E210). Indeed, as shown above, in the case of a vertical dissection plane, the dissection plane is above the focal plane of the dissection device (the Vessel ring 33a is located above the impingement line used to make the dissection) if the conical phase mask used allows the SLM to emulate a positive axicon (in this case the control unit 60 drives the optical focusing system 50 to focus the modulated and deflected laser beam 410 to a desired depth that is smaller than the maximum depth of the vertical dissection plane to be made), - below the focal plane of the dissection device (the Vessel ring 33a is located below the impingement line used to make the dissection) if the conical phase mask used allows the SLM to emulate a negative axicon (in this case the control unit 60 drives the optical focusing system 50 to focus the modulated and deflected laser beam 410 to a desired depth that is greater than the maximum depth of the dissection plane to be made). It can be located at.

[0128] The control unit 60 sends a conical phase mask (ie, an axicon modulation setpoint) to the shaping system 30 to generate a modulated Bessel laser beam (step E220).

[0129] The control unit 60 also activates the movement of the sweeping optical scanner 40 to the initial position of the second optical scanning path.

[0130] - the focusing system 50 and the optical scanner 40 are in place, - a conical phase mask is loaded into the shaping system 30; - The rotation speed of the mirror of the optical scanner 40 is constant. If so, the control unit 60 activates the femtosecond laser source 10 to emit a laser pulse (step E230).

[0131] A femtosecond laser source 10 generates a laser beam 110 that passes through a shaping system 30. The shaping system 30 modulates the phase of the laser beam to generate a single modulated Bessel-type laser beam.

[0132] The modulated Bessel laser beam 310 exits the shaping system 30 and enters an optical scanner 40 which deflects the modulated Bessel laser beam 310 .

[0133] The modulated and deflected laser beam 410 enters an optical focusing system 50, which focuses the beam. A modulation setpoint (i.e., a conical phase mask) applied to the shaping system 30 above or below the focal plane allows the energy to be distributed to an impingement line, which generates an elliptical bubble extending parallel to the optical axis A-A' of the dissection device, as shown in step 620a of FIG. 12.

[0134] The femtosecond laser 1 continues to emit other pulses in the form of a laser beam at a determined rate. Between each pulse, the mirror pivots at a certain angle, which has the effect of moving the collision line and forming a new elliptical bubble along the second optical path (step E240). After a certain number of pulses, this new bubble is adjacent to the previously formed elliptical bubble, as shown in step 620b of FIG. 12, thus forming a vertical cut surface segment.

[0135] The operation of driving the femtosecond laser source 10 and the sweeping optical scanner 40 is repeated to form vertical sections.

[0136] More specifically, pivoting the mirror between each pulse of the femtosecond laser source 10 has the result of moving the collision line and creating a new elliptical bubble offset relative to the previous one until it forms an incision section at the incision plane, as shown in step 620c of FIG. 12.

[0137] Once the incision section is completed, the control unit 60 deactivates the femtosecond laser source 10, controls the movement of the optical focusing system to create a second section of the elliptical bubble above the first section, and then controls the restart of the pivoting of the mirror again in the opposite direction and reactivates the femtosecond laser source 10, as shown in step 630c of FIG. 12.

[0138] The laser beam 110 passes through the shaping system 30, the optical scanner 40, and the optical focusing system 50. A new section of an elliptical bubble forms at the incision plane, located above and extending in the same plane as the previous section.

[0139] Once the optical scanner 40 has swept through all positions in the second path of travel, the vertical section plane is complete.

[0140] In summary, to create a vertical incision plane, the control unit 60: - applying an axicon modulation setpoint to the shaping system 30 to generate a modulated Bessel-type laser beam from a Gaussian laser beam, where said modulation setpoint comprises a phase mask 314, 315 emulating an axicon applied to a spatial light modulator (SLM), said modulated Bessel-type laser beam creating an impingement line that allows generating an elliptical gas bubble in tissue; - driving the sweeping optical scanner 40 to move the impingement line of the modulated Bessel-type laser beam along a second optical translation path to form a vertical plane consisting of sets of adjacent elliptical bubbles; It is structured as follows.

[0141] As shown in FIG. 13, a set of collision lines L1, L2, and L3 used to create stacked elliptical bubble sections extending across a single vertical cut plane located between two horizontal cut planes H1, H2 is partially shown.

[0142] As shown in Figure 13, the collision lines used to form two consecutive stacked sections partially overlap. In fact, the inventors found that the end points of the collision lines do not have enough energy to form an elliptical bubble. Therefore, the inventors propose overlapping the collision lines used to create stacked elliptical bubble sections.

[0143] In particular, after creating the horizontal cut plane H1, a vertical cut plane located above the horizontal cut plane H1 is created by stacking successive elliptical bubble sections, for example, the first, second and third sections in the embodiment shown in FIG. 13.

[0144] To create the first section (i.e., the section closest to the horizontal dissection plane H1), the control unit 60 is configured to drive the optical focusing system 50 to position the focal plane of the dissection device at a predetermined non-zero distance from the first horizontal dissection plane. This predetermined distance is shorter than the length of the impingement line L1 of the modulated Bessel-type laser beam. Specifically, the predetermined distance may be 1 / 5 to 1 / 3 of the length of the impingement line. Thus, each impingement line L1 used to create the first section partially intersects with the horizontal dissection plane H1. Next, the control unit 60 drives the sweeping optical scanner 40 to move the impingement line L1 along a second optical movement path to form the first section of adjacent elliptical bubbles.

[0145] To create the second section (i.e., the section located above the first section), the control unit 60 is configured to drive the optical focusing system 50 to position the focal plane of the dissection device at a predetermined distance from the first section of the elliptical bubble. Thus, each collision line L2 used to create the second section partially covers the first section of the elliptical bubble. The control unit 60 then drives the sweeping optical scanner 40 to move the collision line L2 along a second optical movement path to form the second section of the adjacent elliptical bubble.

[0146] For the creation of the third section (i.e., the section farthest from the horizontal cutting plane H1), the control unit 60 is configured to drive the optical focusing system 50 to position the focal plane of the cutting device at a predetermined distance from the second section so that the end point of the collision line L3 contacts the elliptical bubble in the second section.

[0147] This ensures that the tissue bridges between the different stacked sections are narrow enough to ensure the practitioner can make incisions of acceptable quality across the entire height of each vertical incision plane.

[0148] 2.5.3. Formation of stacked horizontal and vertical cut planes to create a tissue cube The principles of operation of the incision device in relation to disruption of the lens as part of cataract surgery will now be described in more detail.

[0149] To section the lens into a cube that is aspirated by the aspiration cannula, horizontal and vertical incisions are made by starting at the deepest horizontal incision in the lens and stacking successive vertical and horizontal incisions up to the most superficial horizontal incision in the lens.

[0150] As shown in Figures 14 and 15, the deepest horizontal incision plane H1 is created in the first step (E310, F310). - applying a multi-point phase mask to the shaping system 30 to generate a modulated multi-point laser beam; - controlling the movement of the focusing system 50 to align the focal plane of the dissection device with the desired deepest dissection plane; - driving movement of a sweeping optical scanner along a first optical path to a target location (e.g., in a crenellation); - Activate the femtosecond laser source 10 (after the scanner movement speed has stabilized and reached the target position).

[0151] A series of shots are performed in the focal plane of the dissection device. With each shot, several impact points are simultaneously focused in the focal plane. Each impact point forms a bubble. An optical scanner allows the impact points to be moved in the focal plane between each shot. When the entire surface of the horizontal dissection plane is covered with bubbles, the horizontal dissection plane H1 is completed.

[0152] In a second step (E320 and F320), a first set of adjacent vertical incision planes V1 are created using the incision device. For each vertical incision plane V1, the control unit 60 - applying a conical phase mask to the shaping system 30 to generate a modulated Bessel laser beam; - controlling the movement of the focusing system 50 to position the impingement line at the incision plane (the focusing plane being above or below the incision plane depending on whether the axicon emulated in the shaping system is a positive or negative axicon); - driving movement of the sweeping optical scanner along a second optical path (e.g., segment) to a target location; - Activate the femtosecond laser source 10 (after the scanner movement speed has stabilized and reached the target position).

[0153] A series of shots are performed, each of which generates an impact line, forming an elliptical bubble along the optical axis of propagation of the modulated laser beam. A sweeping optical scanner 40 allows the impact line to be moved above / below the focal plane between each shot. When the entire second path of movement is covered with bubbles, the vertical cut plane V1 is completed.

[0154] If the depth of the collision line is less than the desired depth for the vertical dissection plane, the control unit 60 can monitor the sweeping optical scanner 40 and the optical focusing system 50 to move the collision line along the second optical path by changing the depth of the focal plane of the dissection device for the round trip.

[0155] Several vertical cut planes V1 above the initial horizontal cut plane H1 are thus obtained, which are divided into two different subgroups (first subgroup of faces 107' and second subgroup of faces 107'' in FIG. 2), forming parallel faces within the same subgroup but perpendicular for the different subgroups, thus making it possible to obtain vertical cut planes forming a grid pattern, each elementary square representing a side wall of the cube thus cut.

[0156] In the third step (E330, F330), an intermediate horizontal plane H2 is created over the vertical incision plane V1. This horizontal incision plane H2 is created according to the same method as described for the first step. A lens cube defined between the horizontal and vertical planes created in the first, second, and third steps is thus obtained.

[0157] In a fourth step (E340, F340), a second set of adjacent vertical cutting planes V2 is created using the cutting device. This second set of vertical cutting planes V2 is laterally offset relative to the first set of vertical cutting planes V1. To do so, the control unit 60 drives the movement of the sweeping optical scanner 40 along a different third movement path, which is specifically laterally offset relative to the second optical path. Thus, none of the second set of vertical cutting planes V2 is coplanar with the first set of vertical cutting planes V1.

[0158] In the fifth step (E350, F350), the upper horizontal surface H3 is created using the same method as described for the first step. A two-stage stack of lens cubes is thus obtained, with the lens cubes of the second stage laterally offset relative to the lens cubes of the first stage.

[0159] The process described above can be repeated for any one stack of more than two stages of crystal cubes, with the cubes of one stage being laterally offset from the remaining crystal cubes located in the lower stages.

[0160] 3. conclusion The lateral offset of the vertical cutting plane above the horizontal cutting plane relative to the vertical cutting plane below the horizontal cutting plane makes it possible to limit the propagation of gas bubbles to the surface of the tissue being treated.

[0161] As shown above, in the case of ocular tissue dissection, such propagation can cause gas accumulation above the dissection surface, in the lens, or even above the lens in the anterior chamber of the eye, masking the laser beam and thereby preventing dissection in the anterior portion of the lens.

[0162] Thus, the present invention provides an efficient three-dimensional dissection tool that allows for dissection into elementary portions of the same size and small dimensions.

[0163] The reader will appreciate that numerous modifications may be made to the invention described above without materially departing from the novel teachings and advantages set forth herein.

Claims

1. 1. An apparatus for dissecting human or animal tissue, the apparatus comprising: a femtosecond laser source (10) configured to emit a Gaussian laser beam in the form of pulses; and a device for processing the Gaussian laser beam, the device being arranged downstream of the femtosecond laser source (10), the device comprising: a shaping system (30) arranged on the trajectory of said Gaussian laser beam for modulating the phase of the wavefront of said Gaussian laser beam, said shaping system (30) comprising a spatial light modulator (SLM) and adapted to generate a modulated laser beam from said Gaussian laser beam; a sweeping optical scanner (40) positioned downstream of said shaping system for moving said modulated laser beam; an optical focusing system (50) downstream of the shaping system (30) for focusing the modulated laser beam in a focal plane of the dissection device and for moving the focal plane of the dissection device to a plurality of positions along the optical axis (A-A') of propagation of the modulated laser beam; Equipped with The processing device further comprises a control unit (60) for driving the femtosecond laser source (10), the shaping system (30), the sweeping optical scanner (40) and the optical focusing system (50) to create successive horizontal and vertical section planes, the horizontal section planes extending perpendicular to the optical axis (A-A') and the vertical section planes extending parallel to the optical axis (A-A'), and the control unit (60) - control the creation of a first horizontal incision plane (H1) (E310), Controlling (E320) the creation of a first plurality of vertical cut planes (V1) on a first horizontal cut plane (H1), - controlling (E330) the creation of a second horizontal incision plane (H2) above the first plurality of vertical incisions (V1), wherein the first horizontal incision plane (H1) is deeper in the tissue than the second horizontal incision plane (H2); Controlling (E340) the creation of a second plurality of vertical planes (V2) on a second horizontal plane (H2), wherein the second plurality of vertical cutting planes (V2) are laterally offset with respect to the first plurality of vertical planes (V1). It is configured as follows: An incision device characterized by:

2. 10. The lancing device of claim 1, wherein the second plurality of perpendicular lancing planes are laterally offset relative to the first plurality of perpendicular lancing planes by a distance of between 5 μm and 500 μm.

3. 3. The dissection device of claim 1, wherein the second plurality of perpendicular dissection planes are laterally offset relative to the first plurality of perpendicular dissection planes along first and second axes perpendicular to the optical axis (A-A'), the first and second axes being orthogonal to each other.

4. The control unit (60) controls the following for creating each horizontal section: applying (E120) a multi-point phase mask to the shaping system (30) to generate a single modulated multi-point laser beam, wherein the multi-point phase mask is calculated to distribute the energy of the modulated multi-point laser beam to at least two impingement points in the focal plane of the dissection device, controlling (E110) the movement of the focusing system (50) to match the focal plane of the dissection device with the desired depth for the horizontal dissection plane, driving the sweeping optical scanner to move the impact point of the single modulated multi-point laser beam along a first path of movement (E140); Activating the femtosecond laser source (10) (E130) The incision device according to any one of claims 1 to 3, which is configured as follows.

5. The control unit (60) performs the following steps to generate each vertical cutting plane (V1) of the first plurality of vertical cutting planes: applying (E220) an axicon modulation setpoint to the shaping system (30) to generate a modulated Bessel-type laser beam from the Gaussian laser beam, wherein the modulation setpoint comprises a phase mask (314, 315) emulating an axicon applied to the spatial light modulator (SLM), the modulated Bessel-type laser beam creating an impingement line that allows generating an elliptical gas bubble in the tissue; Driving the sweeping optical scanner to move the impingement line of the modulated Bessel-type laser beam along a second optical movement path to form a set of adjacent elliptical bubbles (E240). The incision device according to any one of claims 1 to 4, which is configured as follows.

6. The control unit (60) performs the following steps to generate each vertical section (V2) of the second plurality of vertical sections: applying (E220) said axicon modulation setpoint to said shaping system (30); Driving the sweeping optical scanner to move the line of impingement of the modulated Bessel-type laser beam along a third optical path that is laterally offset relative to the second optical path (E240). The incision device according to claim 5 , wherein the incision device is configured as follows:

7. Each vertical section is made up of a stack of several sets of adjacent oval bubbles, and said control unit (60) o driving the optical focusing system (50) to position the focal plane of the cutting device at a predetermined non-zero distance from the first horizontal cutting plane, wherein the predetermined distance is less than a length of the line of impingement of the modulated Bessel-type laser beam such that the line of impingement partially intersects the first horizontal cutting plane; driving the sweeping optical scanner to move the line of impingement of the modulated Bessel-type laser beam to form a first set of adjacent elliptical bubbles; activating the optical focusing system (50) to position the focal plane of the lancing device at a predetermined distance from the first set of adjacent elliptical bubbles such that the impingement line partially intersects the first set of adjacent elliptical bubbles; Activating the sweeping optical scanner to move the impingement line of the modulated Bessel-type laser beam to form a second set of adjacent elliptical bubbles. The incision device according to claim 5 or 6, which is configured as follows.

8. The incision device according to claim 7, wherein the predetermined distance is 1 / 5 to 1 / 3 of the length of the collision line.

Images