Ophthalmological laser therapy system and method, beam splitter for a laser therapy system, method and device for generating control data, and a software product for performing said methods

Abstract

The invention provides an ophthalmological laser therapy system for treating a patient's eye, having a laser means (4) for emitting a pulsed laser beam (6), a beam splitter (33) for generating a plurality of pulsed partial beams from the pulsed laser beam (6) a scanning device (8) for moving the pulsed partial beams along a scanning direction, a control device (11) for controlling the scanning device (8), and a focusing device (108) for focusing the pulsed partial beams as partial beam spots (19_1, 19_2, 19_3, 19_4) arranged in a spot pattern (34) into the patient's eye (2), wherein the control device (11) controls the scanning device (8) in such a way that two directly adjacent spot patterns (34) are spaced apart along the scanning direction.

Description

[0001] Ophthalmological laser therapy system and method, beam splitter for a laser therapy system, method and device for generating control data and software product for carrying out the said methods

[0002] The invention relates to an ophthalmic laser therapy system and method, a beam splitter for a laser therapy system, a method and device for generating control data, and a software product for implementing said methods. In particular, it is intended to enable the generation of cut surfaces in patients' eyes.

[0003] Human vision problems have long been corrected using lenses in the form of glasses. Recently, there have been various approaches to correcting visual impairment by modifying the cornea. The modification is intended to change the curvature of the cornea. To correct myopia, the front surface of the cornea must be flattened, which is why the volume to be removed is thicker in the center, i.e. in the area of ​​the visual axis, than at the edges. To correct hyperopia, on the other hand, the front surface of the cornea must be curved more sharply, which is why the volume to be removed is thicker at the edges than in the center. The overall imaging properties of the eye are thereby influenced in such a way that visual impairment is reduced or, ideally, even completely corrected.

[0004] Various surgical methods are known for this type of vision correction. In the so-called LASIK procedure according to EP 1 719 483 A1, a corneal flap is first detached from the surface of the cornea on one side and folded to the side. This exposes the interior of the cornea, from which material is then vaporized using an ablating laser. If the corneal flap is then folded back in, the natural front surface of the cornea remains intact. Because material has been vaporized inside the cornea, the front surface of the cornea has a different curvature, which is dimensioned such that a previously existing vision defect is corrected. The material is removed by ablation. Ablation, also known as photoablation, vaporizes tissue when laser radiation is absorbed upon impact with the tissue surface.Pulsed laser radiation is used, and each pulse vaporizes a certain volume of material from the corneal tissue. A large number of shots are distributed over the exposed interior of the cornea so that the desired material is ablated overall. This ablation must be distinguished from the creation of a cutting surface inside the tissue according to WO 2005 / 01 1545 A1, which, for example, acts as a boundary surface to delimit a piece of tissue and make it removable. Unlike ablation, this method uses laser radiation that penetrates through the surface into the material and is therefore not absorbed at the surface. This laser radiation is bundled into a focus inside the tissue in the form of short pulses. This achieves a specific power density at a specific location and time at the focus, so that tissue layers inside the tissue are separated. The separation essentially takes place in the focus or in the close spatial area around this focus.A so-called optical breakthrough (e.g., in the form of a plasma bubble or micro-gas bubble) can occur in or around the focus. However, approaches that work without such a breakthrough are also known, for example, by overlapping multiple focus positions. In all cases, a multitude of optical focus positions creates a 3-dimensional cut surface directly inside the tissue, which acts as an interface to delimit a piece of tissue and make it removable.

[0005] A very successful procedure was developed by Carl Zeiss Meditec AG under the name SMILE (see e.g. DE 10 2007 019 813 A1). It uses pulsed laser radiation to isolate a lenticule in the cornea. The lenticule can then be removed from the cornea through a lateral incision that leads to the surface of the cornea and serves as a working channel. For this purpose, suitable incision surfaces are created in the corneal tissue using a large number of laser pulse foci. This large number is arranged in a specific pattern in the cornea, which ultimately defines the shape and position of the incision surfaces. The piece of tissue comprising the lenticule is structured and sized in such a way that the front surface of the cornea changes its curvature as required for the correction. The procedure brings about a subtractive correction because volume is removed. Another approach inserts implants into the cornea.For this purpose, a slit is made in the cornea into which the implant is inserted. It is designed to change the curvature of the anterior surface of the cornea in the desired manner. This approach thus achieves an additive correction by adding volume. In both cases, an incision must be made inside the cornea. This is done using pulsed laser radiation.

[0006] The invention is based on the object of providing an improved ophthalmic laser therapy system and an improved ophthalmic laser therapy method. In particular, incisions in the patient's eye should be able to be created more quickly. The invention is characterized in the independent claims. The dependent claims relate to preferred developments.

[0007] An ophthalmological laser therapy system for treating a patient's eye is provided, the laser therapy system comprising a laser device for emitting a pulsed laser beam, a beam splitter for generating a plurality of pulsed partial beams from the pulsed laser beam, a scanning device for moving the pulsed partial beams along a scanning direction, a control device for controlling the scanning device, and a focusing device for focusing the pulsed partial beams into the patient's eye as partial beam spots arranged in a spot pattern.

[0008] The control device can control the scanning device such that (preferably each) two spot patterns directly adjacent along the scanning direction are spaced apart from each other. In particular, the control device can control the scanning device such that (preferably each) two spot patterns directly adjacent along the scanning direction do not overlap (even partially). Furthermore, the control device can control the scanning device such that no directly adjacent spot patterns overlap (even partially) along the scanning direction. Preferably, all spot patterns are spaced apart from each other.

[0009] In particular, the control device can control the scanning device in such a way that a predetermined cross-sectional area (preferably in a human or animal eye) is generated. Therefore, one can also speak of an area scan to generate the predetermined cross-sectional area.

[0010] The control device can thus control the scanning device such that the described spacing (and / or the spacing variants described below) of two spot patterns directly adjacent along the scanning direction is present in the entire area scan or only in a part or region (or in several parts or regions) of the area scan. The spacing can, for example, only be present in a central region or only outside the central region of the area scan. Additionally or alternatively, the spacing can, for example, be present for at least 40%, 50%, 60%, 70%, 80%, or 90% of the area scan.

[0011] This allows more spots to be generated in the same amount of time compared to the previous single spot. Furthermore, a homogeneous distribution of the partial beam spots is achieved. This allows, for example, a cutting surface to be created more quickly. Cutting times can be halved compared to previous times.

[0012] A patient’s eye is understood here to mean, in particular, a human eye or an animal eye.

[0013] The scanning device can guide the spot pattern along a predetermined path (which can also be referred to as scanning) in an unchanged orientation (in particular, no rotation about an axis parallel to the propagation direction of the partial beams occurs during scanning). This offers the advantage that the beam splitter does not need to be moved (e.g., rotated) during scanning. The beam splitter thus remains stationary at the position it is positioned for beam splitting.

[0014] Furthermore, the scanning device can guide the spot pattern in an unchanged form along a predetermined path.

[0015] The scanning device can guide the spot pattern in a predetermined plane or a projection onto the predetermined plane along a spiral path, an elliptical spiral path and / or along at least one annular path (a closed or an open annular path).

[0016] In particular, the spot pattern may have a minimum partial beam spot spacing and a maximum partial beam spot spacing and the spot pattern may have a center point.

[0017] The control device can control the scanning device such that two spot patterns directly adjacent along the scanning direction have a minimum first pattern spacing of greater than or equal to the sum of the minimum and maximum partial beam spot spacing and less than or equal to twice the sum of the minimum and maximum partial beam spot spacing, wherein the first pattern spacing is the spacing of the centers of directly adjacent spot patterns along the scanning direction.

[0018] Additionally or alternatively, the control device can control the scanning device such that the minimum distance of any partial beam spot of a first spot pattern from any partial beam spot of a second spot pattern that is directly adjacent to the first spot pattern along the scanning direction is greater than or equal to n times the minimum partial beam spot distance, where n is in the range of 0.5 - 2 (including the range boundaries). Furthermore, n can be in the range of 0.6 - 1.9; 0.7 - 1.8; 0.8 - 1.7; 0.9 - 1.6 or 1 - 1.5 (each including the range boundaries).Additionally or alternatively, the control device can control the scanning device such that a minimum first scanning distance between two spot patterns directly adjacent along the scanning direction is greater than or equal to 0.5 times the minimum partial beam spot spacing and less than or equal to 2 times the minimum partial beam spot spacing, wherein the minimum first scanning distance is the minimum distance between two partial beam spots of directly adjacent spot patterns along the scanning direction. The minimum first scanning distance can be greater than or equal to 0.6 times, 0.7 times, 0.8 times, 0.9 times, or 1 times the minimum partial beam spot spacing. Furthermore, the minimum first scanning distance can be less than or equal to 1.9 times, 1.8 times, 1.7 times, 1.6 times, or 1.5 times the minimum partial beam spot spacing.

[0019] Additionally or alternatively, the control device can control the scanning device such that (preferably in each case) two spot patterns directly adjacent transversely to the scanning direction are spaced apart from each other. In particular, the control device can control the scanning device such that (preferably in each case) two spot patterns directly adjacent transversely to the scanning direction do not overlap (even partially). Furthermore, the control device can control the scanning device such that no directly adjacent spot patterns overlap (even partially) transversely to the scanning direction. Preferably, all spot patterns are spaced apart from each other.

[0020] The control device can control the scanning device such that two spot patterns directly adjacent transversely to the scanning direction have a minimum second pattern spacing of greater than or equal to the sum of the minimum and maximum partial beam spot spacing and less than or equal to twice the sum of the minimum and maximum partial beam spot spacing, wherein the second pattern spacing is the spacing of the centers of directly adjacent spot patterns transversely to the scanning direction.

[0021] Additionally or alternatively, the control device can control the scanning device such that the minimum distance between any partial beam spot of a first spot pattern and any partial beam spot of a second spot pattern that is directly adjacent to the first spot pattern transversely to the scanning direction is greater than or equal to m times the minimum partial beam spot distance, where m is in the range of 0.5 - 2 (including the range limits). Furthermore, m can be in the range of 0.6 - 1.9; 0.7 - 1.8; 0.8 - 1.7; 0.9 - 1.6 or 1 - 1.5 (each including the range limits).Additionally or alternatively, the control device can control the scanning device such that a minimum second scanning distance between two spot patterns directly adjacent perpendicular to the scanning direction is greater than or equal to 0.5 times the minimum partial beam spot spacing and less than or equal to 2 times the minimum partial beam spot spacing, wherein the minimum second scanning distance is the minimum distance between two partial beam spots of directly adjacent spot patterns perpendicular to the scanning direction. The minimum second scanning distance can be greater than or equal to 0.6 times, 0.7 times, 0.8 times, 0.9 times or 1 times the minimum partial beam spot spacing. Furthermore, the minimum first scanning distance can be less than or equal to 1.9 times, 1.8 times, 1.7 times, 1.6 times or 1.5 times the minimum partial beam spot spacing.

[0022] The beam splitter can be part of the beam path and permanently positioned in the beam path. However, it is also possible for the beam splitter to be moved out of the beam path, preventing beam splitting. In this case, the pulsed laser beam is moved by the scanning device and focused into the patient's eye by the focusing device. This allows the laser therapy system to provide two modes: a fast mode with the partial beam spots (when the beam splitter is in the beam path) and a basic mode without a beam splitter in the beam path. The same paths can be scanned in both modes using the scanning device.

[0023] A higher scanning speed is advantageous to reduce the risk of the patient's eye moving during section creation or of the patient's eye detaching from the contact lens ("suction loss").

[0024] The laser therapy system can be configured such that the pulse energy of each partial beam spot in fast mode is the same as the pulse energy of the individual spot of the pulsed laser beam in basic mode. This specifically means that the pulse energies do not differ by more than 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1%.

[0025] In order to provide the same pulse energies in both modes, the power of the laser device can be adjusted accordingly.

[0026] It is possible to provide various beam splitters, each of which can be selectively inserted into the beam path. The various beam splitters can differ, for example, in the number of generated partial beams, the propagation directions of the generated partial beams, and / or the spot patterns that can be generated using the generated partial beams. This allows for various fast modes to be realized.

[0027] The beam splitter can be pivoted or retracted using a motor, e.g., a stepper motor. The beam splitter can be retracted before the start of treatment (or the ophthalmic laser treatment), and the beam splitter can remain in this position throughout the entire treatment.

[0028] An ophthalmic laser therapy system for treating a patient's eye is provided, the laser therapy system comprising a laser device for emitting a pulsed laser beam, a scanning device for moving the pulsed laser beam, a control device for controlling the scanning device, and a focusing device for focusing the pulsed laser beam into the patient's eye.

[0029] The laser therapy system may further comprise a beam splitter that can be moved back and forth between a rest position in which it is not exposed to the pulsed laser beam and a working position in which it is exposed to the pulsed laser beam, wherein the beam splitter, when in the working position, splits the pulsed laser beam into a plurality of pulsed partial beams, which are then focused into the patient's eye by means of a focusing device as partial beam spots arranged in a spot pattern.

[0030] An actuator, such as a stepper motor, may be provided to move the beam splitter back and forth between the rest and working positions.

[0031] It can therefore be said that when the beam splitter is in the rest position, the laser therapy system is a monospot system, whereas when the beam splitter is in the working position, the laser therapy system is a multispot system.

[0032] This allows for a high degree of flexibility in the use of the laser therapy system. For example, if the scanning device is traversing a spiral path, the laser therapy system can be used as a monospot system for short distances from the spiral center. At greater distances from the spiral center, the laser therapy system can be used as a multispot system.

[0033] When used as a monospot system, the laser therapy system can continue to operate at a single laser frequency, whereas when used as a multispot system, a lower laser frequency is used. The laser frequency refers specifically to the time interval between the placement of adjacent spots or adjacent spot patterns (hereinafter also referred to as multispot patterns).

[0034] For a spot pattern consisting of at least two partial beam spots, the laser frequency can be halved in multi-spot mode, for example.

[0035] However, it is particularly advantageous to carry out the entire treatment with a fixed multi-spot pattern (with the beam splitter pivoted in), as this eliminates time-consuming switching and allows the eye to be treated as quickly as possible.

[0036] According to the invention, incisions can also be performed with the multispot pattern that require a rapid change in the position of the multispot pattern along the propagation direction of the partial beams. These can be incisions whose main direction is oriented from deeper areas of the cornea toward the corneal surface, such as access or marginal incisions of the lenticule.

[0037] The beam splitter (hereinafter also referred to as a beam multiplier) can comprise at least one birefringent element or a birefringent module. A birefringent element or a birefringent module is understood here in particular to be an element / module that splits an incident beam into (at least) two outgoing partial beams by means of birefringence. The birefringent element or the birefringent module can comprise at least one crystal-optical component. This allows for the realization of a very compact and / or lightweight beam splitter. This simplifies, for example, moving the beam splitter from the working position to the rest position and vice versa.

[0038] Additionally or alternatively, the birefringent element or birefringent module can also comprise liquid crystals. Additionally or alternatively, the birefringent element or birefringent module can exhibit birefringent properties that can be generated by means of electric and / or magnetic fields. Additionally or alternatively, the birefringent element or birefringent module can exhibit birefringent properties that can be generated by means of mechanical pressure or tension.

[0039] The beam splitter can comprise exactly two, exactly three, exactly four, exactly five, or even more birefringent crystal elements. Additionally or alternatively, the beam splitter can comprise at least one Wollaston prism, at least one Rochon prism, at least one Senarmont prism, and / or at least one Nomarski prism.

[0040] Additionally or alternatively, the beam splitter can have at least one Z / 2 layer, at least one Z / 4 layer, at least one V2 plate and / or at least one V4 plate. The at least one V2 layer, at least one V4 layer, at least one 4 / 2 plate and / or at least one 4 / 4 plate can be arranged between two birefringent elements or two birefringent modules (in particular between two of the aforementioned prisms). The at least one 4 / 2 layer, at least one 4 / 4 layer, at least one 4 / 2 plate and / or at least one 4 / 4 plate can additionally or alternatively be arranged in front of the first birefringent element or in front of the first birefringent module, so that the pulsed laser beam passes through the at least one 4 / 2 layer, the at least one 4 / 4 layer, the at least one 4 / 2 plate and / or the at least one 4 / 4 plate before it strikes the first birefringent element or the first birefringent module.

[0041] With a 4 / 2 layer or 4 / 2 plate, for example, one can rotate a linear polarization by a desired angle (the angle of rotation can, in particular, correspond to twice the angle between the polarization direction and the so-called "fast" axis of the 4 / 2 layer or 4 / 4 plate). With a 4 / 4 layer or 4 / 4 plate, for example, one can generate elliptically (or circularly) polarized light from linearly polarized light. Circularly polarized light can be generated if the "fast axis" of the 4 / 4 layer or 4 / 4 plate forms an angle of 45° with the polarization direction. With the at least one 4 / 2 layer, the at least one 4 / 4 layer, the at least one 4 / 2 plate, and / or the at least one 4 / 4 plate, one can thus, for example,ensure that the polarization behind the at least one 4 / 2 layer, the at least one 4 / 4 layer, the at least one A / 2 plate and / or the at least one A / 4 plate has a polarization that can be split again by means of birefringence and / or with which the pulsed laser beam hits the first birefringent element or the first birefringent module.

[0042] Additionally or alternatively, the beam splitter may comprise a first and a second birefringent element (e.g. a birefringent crystal), wherein the first birefringent element splits an incident beam into two partial beams that lie in a first plane and diverge in this plane, wherein the second birefringent element splits an incident beam into two partial beams that lie in a second plane and diverge in this plane, wherein both birefringent elements are positioned one behind the other such that the two partial beams generated by the first birefringent element strike the second birefringent element and are each split into two partial beams, and wherein the second birefringent element is rotated relative to the first birefringent element about an axis parallel to the direction of the incident beam by an angle such thatthat the two planes enclose an angle from the range 70° - 110° (including the range limits) or from the range 80° - 100° (including the range limits), preferably an angle of 81°, 82°, 83°, 84°, 85°, 86°, 87°, 88°, 89°, 91°, 92°, 93°, 94°, 95°, 96°, 97°, 98°, 99° and particularly preferably an angle of 90°.

[0043] Furthermore, at least one V2 layer, at least one V4 layer, at least one V2 plate and / or at least one V4 plate can be arranged between the two birefringent elements.

[0044] Additionally or alternatively, the beam splitter may comprise three partial prisms with two inner boundary surfaces, wherein at least two of the three partial prisms each comprise a birefringent element or a birefringent crystal in such a way that a beam is split into two partial beams lying in a first plane and diverging in this plane when passing through a first of the inner boundary surfaces, and that a beam is split into two partial beams lying in a first plane and diverging in this plane when passing through a second of the inner boundary surfaces.

[0045] The partial prisms and / or the inner boundary surfaces can be oriented such that the two planes enclose an angle from the range 70° - 110° (including the range boundaries) or from the range 80° - 100° (including the range boundaries), preferably an angle of 81°, 82°, 83°, 84°, 85°, 86°, 87°, 88°, 89°, 91°, 92°, 93°, 94°, 95°, 96°, 97°, 98°, 99° and particularly preferably an angle of 90°.

[0046] An ophthalmic laser therapy system for treating a patient's eye is provided, the laser therapy system comprising a laser device for emitting a pulsed laser beam, a beam splitter for generating a plurality of pulsed partial beams from the pulsed laser beam, a scanning device for moving the pulsed partial beams, a control device for controlling the scanning device, and a focusing device for focusing the pulsed partial beams into the patient's eye as partial beam spots arranged in a spot pattern, the beam splitter comprising at least one first birefringent element (or a first birefringent module) that generates the plurality of pulsed partial beams.

[0047] The beam splitter may comprise a second birefringent element (or a second birefringent module) arranged downstream of the first birefringent element, wherein the first birefringent element splits the pulsed laser beam into a first and a second pulsed partial beam, and wherein the second birefringent element splits the first pulsed partial beam into a third and fourth pulsed partial beam and the second pulsed partial beam into a fifth and sixth pulsed partial beam, so that four pulsed partial beams emanate from the second birefringent element.

[0048] In the laser therapy system, four partial beams (and thus four partial beam spots) can be generated by means of the beam splitter, which lie on the corners of a polyhedron, in particular on the corners of a rectangle or a square.

[0049] The beam splitter can be designed so that the partial beams do not exit the beam splitter parallel to each other. Upon exiting the beam splitter, the partial beams can form an angle to each other that is less than or equal to the quotient of a times the wavelength of the partial beams and the beam diameter D of the partial beams, where a is greater than or equal to 1 and less than or equal to 5 (for a typical wavelength of, for example, 1040 nm and a beam diameter of approximately 5 mm, the angle can be less than or equal to 2 minutes).

[0050] The beam splitter can be designed such that at least three partial beams are generated. The intersection points of the at least three partial beams with an imaginary plane transverse to the propagation direction of the partial beams preferably do not lie on a line and / or cover a flat area in the imaginary plane. The at least three partial beams or their intersection points with the imaginary plane can lie at the corners of a triangle, a quadrilateral, a pentagon, a hexagon or another polygon. Furthermore, the at least three partial beams or their intersection points with the imaginary plane can be distributed evenly or irregularly in the flat area (which can be designed, for example, as a triangle, quadrilateral, pentagon, hexagons or another polygon).

[0051] The beam splitter can preferably be positioned so that the pulsed laser radiation hits the beam splitter as collimated radiation. One can also say that the beam splitter can be positioned in the collimated beam path. The beam splitter can be transmissive and / or reflective.

[0052] The beam splitter can be designed such that the at least three partial beams each have the same pulse energy. This particularly means that the pulse energies do not differ by more than 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1%.

[0053] Additionally or alternatively, the beam splitter can be configured so that the pulses of the individual partial beams are present simultaneously. This specifically means that the pulses of two partial beams are temporally offset (or spaced) from each other by less than 250 times, 100 times, 50 times, or 10 times (or any other integer value between 250 and 10) the pulse duration of the pulses of one of the two partial beams.

[0054] The beam splitter can be configured to generate 2, 4, 8, 16, 32, 64, or 128 (or any other power of two) from the pulsed laser beam. Of course, any other integer values ​​between 2 and 128 can also be generated (for example, by selective shading and / or deflection into at least one beam trap).

[0055] The partial beam spots can be used to create a cut surface in the patient's eye (particularly in a human eye). In particular, these can be lenticule cuts or lenticule cut surfaces (e.g., anterior lenticule cut surface, posterior lenticule cut surface, lenticule edge cut surface), opening cut surfaces for, e.g., a lenticule, a flap cut surface, or another cut surface in the patient's eye.

[0056] The scanning device can have a z-scanner, which serves to adjust the laser spots in the propagation direction of the partial beams and / or to adjust the laser spot in the propagation direction of the laser beam. The beam splitter can be arranged or positionable between the laser device and the z-scanner. In particular, the beam splitter can be the last optical element before the z-scanner. It can also be said that no further optical element is arranged between the z-scanner and the beam splitter and / or that the z-scanner and the beam splitter are directly adjacent.

[0057] Thus, the beam splitter can be arranged as the last element before the z-scanner, after all other elements for modifying and / or monitoring the laser (such as pulse pickers, power / pulse controls, therapy shutters, confocal detectors, etc.), without these other elements for modifying and / or monitoring the laser having to be changed or adapted. Furthermore, the scanning device can have an xy scanner, which is preferably arranged downstream of the z-scanner. The xy scanner serves in particular to deflect the laser spot(s) in a plane transverse to the propagation direction of the partial beams (e.g., along an elliptical trajectory or an elliptical spiral). The z-scanner can shift the spot pattern in depth out of the predetermined plane so that it lies, for example, on a spherical, aspherical, conical surface, another curved surface, and / or a surface inclined to the xy plane (curved or flat).

[0058] A beam splitter for a laser therapy system is provided, the beam splitter comprising a first birefringent element which splits an supplied laser beam into a first and a second partial beam, the beam splitter further comprising a second birefringent element arranged downstream of the first birefringent element, the second birefringent element splitting the first partial beam into a third and fourth partial beam and the second partial beam into a fifth and sixth partial beam, such that four partial beams emanate from the second birefringent element.

[0059] Overall, the following effects according to the invention, which can be achieved individually and / or in any combination, can be highlighted:

[0060] Fixed partial spot pattern in the scan (e.g. spiral scan, scan along a ring-shaped path, along an elliptical path or an elliptical spiral), where the spot pattern itself is not rotated or turned

[0061] Fast mode with switchability by swiveling or retracting (as well as extending or unwinding) the beam splitter

[0062] Miniaturized assembly comprising at least one crystal-optical component for implementing the beam splitter; preferably, the extent of the beam splitter in a plane perpendicular to the propagation direction of the pulsed laser beam is such that its extent in two mutually perpendicular directions (e.g., x- and y-directions when the pulsed laser beam propagates in the z-direction) lying in the plane is equal.

[0063] A device for generating control data for generating at least one cut surface in a patient's eye is provided, the device comprising: an interface for receiving data for the cut surface to be generated, a calculation device connected to the interface and configured

[0064] - for receiving the data for the cutting surface to be created and - for calculating the control data for a scanning device in order to be able to create the cutting surface with partial beam spots arranged in a spot pattern, which are moved in the patient's eye by means of the scanning device.

[0065] The calculation device can be configured to calculate the control data such that, when generating the cutting surface based on the calculated control data, two spot patterns directly adjacent along a scanning direction of the scanning device are spaced apart from each other. Preferably, the two spot patterns directly adjacent along the scanning direction do not overlap.

[0066] A method is provided for generating control data for generating at least one cut surface in a patient's eye, the method comprising:

[0067] - Receiving data for the cutting surface to be created and

[0068] - Calculating the control data for a scanning device in order to be able to generate the cutting surface with partial beam spots arranged in a spot pattern, which are moved in the patient's eye by means of the scanning device.

[0069] The control data can be calculated in such a way that the intersection surface with the partial beam spots arranged in the spot pattern, which are moved along a scanning direction in the patient's eye by the scanning device, can be generated in such a way that two spot patterns directly adjacent along a scanning direction of the scanning device are spaced apart from each other. Preferably, the two spot patterns directly adjacent along the scanning direction do not overlap.

[0070] An ophthalmological laser therapy method for treating a patient's eye is provided, in which a pulsed laser beam is emitted, a plurality of pulsed partial beams are generated from the pulsed laser beam, the pulsed partial beams are moved and focused into the patient's eye as partial beam spots arranged in a spot pattern such that (preferably in each case) two spot patterns directly adjacent along the scanning direction are spaced from one another.

[0071] An ophthalmological laser therapy method for treating a patient's eye is provided, in which a pulsed laser beam is emitted, the pulsed laser beam is moved and focused into the patient's eye, wherein a beam splitter is further provided which can be moved back and forth between a rest position in which it is not exposed to the pulsed laser beam and an operating position in which it is exposed to the pulsed laser beam, wherein the beam splitter, when in the operating position, splits the pulsed laser beam into a plurality of pulsed partial beams which are then focused into the patient's eye as partial beam spots arranged in a spot pattern.

[0072] In laser therapy, the pulsed partial beams can be generated using at least one birefringent element.

[0073] An ophthalmological laser therapy method for treating a patient's eye is provided, in which a pulsed laser beam is emitted, a plurality of pulsed partial beams are generated from the pulsed laser beam, the pulsed partial beams are moved and focused into the patient's eye as partial beam spots arranged in a spot pattern, wherein the pulsed partial beams are generated by means of at least one first birefringent element.

[0074] In the laser therapy method, a second birefringent element can be provided which is arranged downstream of the first birefringent element, wherein the first birefringent element splits the pulsed laser beam into a first and a second pulsed partial beam and wherein the second birefringent element splits the first pulsed partial beam into a third and fourth pulsed partial beam and the second pulsed partial beam into a fifth and sixth pulsed partial beam, so that four pulsed partial beams emanate from the second birefringent element.

[0075] In laser therapy, the partial beam spots can be used to create an incision in the patient’s eye.

[0076] The laser therapy method can be further developed so that all methods that can be carried out with the ophthalmological laser therapy systems according to the invention (including all further developments) can be carried out.

[0077] The device and the method for generating control data for generating at least one cutting surface in a patient's eye can be further developed such that all methods that can be carried out with the ophthalmological laser therapy systems according to the invention (including all further developments) and / or all ophthalmological laser therapy methods according to the invention (including all further developments) can be carried out based on the generated control data.

[0078] A computer program product is provided comprising program code which, when loaded into a computer, executes a method as described above.

[0079] The described method for generating control data can comprise the preparation for generating at least one cutting surface (in particular for the purpose of correcting the refraction of an eye through corneal modification) and does not yet require the cutting surface generation itself, i.e., in particular, does not require a surgical step. However, it can be supplemented by a cutting surface generation step. In this step, a laser device for generating the cutting surface and / or one of the ophthalmic laser therapy systems according to the invention can then be used.

[0080] The method for creating at least one cut surface can be performed without intervention on the living human or animal body, e.g., for the production of an implant to be inserted (later) from dead donor tissue or artificial tissue material. Likewise, testing, investigation, or demonstration of the creation of at least one cut surface on dead material, e.g., enucleated animal eyes, is possible.

[0081] The creation of the incision surface can preferably be further developed into an ophthalmic laser therapy method for treating a patient's eye and / or into a surgical method for correcting refractive errors in the eye. For example, a piece of tissue in the cornea can be isolated and removed from the cornea in order to achieve refractive error, for example.

[0082] The method for generating control data can, in principle, be carried out using a computer, in particular comprising a processor. This computer can be configured as a planning station, as is otherwise known in the prior art.

[0083] The invention encompasses a software product for implementing the method for generating control data, the method for generating at least one cutting surface, and / or the method for correcting refractive errors of the eye, since the calculation of the cutting surface(s) and the determination of control data for the device, as well as the control of the device, can be easily performed by appropriate software. The device provided according to the invention corresponds to the described method, wherein a calculation device is provided which is configured to execute the corresponding method steps.

[0084] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations indicated, but also in other combinations or in isolation, without departing from the scope of the present invention.

[0085] The invention is explained in more detail below using exemplary embodiments with reference to the attached drawings, which also disclose features essential to the invention. These exemplary embodiments are for illustrative purposes only and are not to be interpreted as restrictive. For example, a description of an embodiment with a large number of elements or components should not be interpreted to mean that all of these elements or components are necessary for implementation. Rather, other embodiments may also contain alternative elements and components, fewer elements or components, or additional elements or components. Elements or components of different embodiments may be combined with one another unless otherwise stated. Modifications and variations described for one of the embodiments may also be applicable to other embodiments.To avoid repetition, identical or corresponding elements in different figures are designated by the same reference numerals and are not explained more than once. The figures show:

[0086] Fig. 1 is a schematic representation of a treatment device with a planning device for generating a cutting surface for ophthalmic surgical refraction correction;

[0087] Fig. 2 is a schematic representation of the effect of the laser radiation used in the treatment device of Fig. 1;

[0088] Fig. 3a is a schematic representation of a scanner 8 of the treatment device 1 of Fig. 1;

[0089] Fig. 3b shows a more detailed representation of the scanner 8 of Fig. 3a;

[0090] Fig. 4 is a schematic sectional view through the cornea illustrating the removal of a piece of corneal tissue in connection with ophthalmic refractive correction; Fig. 5 is a schematic representation of the structure of the treatment device of Fig. 1, with particular reference to the planning device present therein;

[0091] Fig. 6 is a block diagram of a method for determining essential data for cutting surface generation;

[0092] Fig. 7 shows a single spiral path 30 projected onto the xy plane;

[0093] Fig. 8 shows five concentric circles 31 1 , 312, 313, 314 and 31 s, along which the laser radiation 7 can be guided in order to produce the desired cutting surface;

[0094] Fig. 9 is a schematic diagram explaining the spot patterns 34;

[0095] Fig. 10 is a schematic diagram to explain further spot patterns 34;

[0096] Fig. 1 1 is a schematic representation to explain further spot patterns 34;

[0097] Fig. 12 is a schematic diagram to explain the movement of the spot pattern 34 according to Fig. 10 along the spiral path 30 of Fig. 7;

[0098] Fig. 13 is a schematic diagram to explain the movement of the spot pattern 34 according to Fig. 10 along the spiral path 30 of Fig. 7;

[0099] Fig. 14 is a schematic diagram to explain the movement of the spot pattern 34 according to Fig. 10 along the spiral path 30 of Fig. 7;

[0100] Fig. 15 is a schematic diagram illustrating birefringence with a Wollaston prism;

[0101] Fig. 16 is a schematic exploded view of a beam splitter structure according to Fig. 3a;

[0102] Fig. 17 is a schematic exploded view of an alternative construction of a beam splitter according to Figure 3a, and

[0103] Fig. 18 is a schematic exploded view of a modification of the beam splitter structure according to Fig. 17. A treatment device 1 for eye surgery is shown in Fig. 1. The treatment device 1 is designed for making incisions inside an eye 2 of a patient 3. For this purpose, the treatment device 1 has a laser device 4 which emits a laser beam 6 from a laser source 5, which is directed as a focused beam 7 into the eye 2 or the cornea. Preferably, the laser beam 6 is a pulsed laser beam with a wavelength between 300 nanometers and 10 micrometers. Furthermore, the pulse length of the laser beam 6 is in the range between 1 femtosecond and 100 nanoseconds, with pulse repetition rates of 50 to 20,000 kilohertz and pulse energies between 0.01 microjoules and 0.01 millijoules being possible.The treatment device 1 creates a cut surface in the cornea of ​​the eye 2 by deflecting the pulsed laser radiation. For this purpose, a scanner 8 (hereinafter also referred to as scanning device 8 or focus position adjustment mechanism 8) and a radiation intensity modulator 9 are provided in the laser device 4 or its laser source 5.

[0104] The patient 3 is located, for example, on a couch 10 that is adjustable in three spatial directions in order to align the eye 2 to match the incidence of the laser beam 6. In a preferred design, the laser device 4 is adjustable (preferably by motor). Adjustment of the couch 10 is possible alternatively or additionally. The control can be effected in particular by a control unit 11 that basically controls the operation of the treatment device 1 and is connected to the treatment device 1 via suitable data connections, for example connecting lines 12. Of course, this communication can also take place via other means, for example fiber optics or radio. The control unit 11 makes the corresponding settings and time control on the treatment device 1, in particular the laser device 4, and thus carries out a corresponding process sequence on the treatment device 1.

[0105] The treatment device 1 has a fixation device 15, which fixes the cornea of ​​the eye 2 in position relative to the laser device 4. The fixation device 15 can be applied to the cornea by negative pressure in order to fix the eye 2. In embodiments, it can additionally impart a desired geometric shape to the cornea. The fixation unit 15 can comprise a contact glass 45 or be designed as a contact glass 45. Such contact glasses are known to the person skilled in the art from the prior art, for example from DE 10 2005 040 338 A1. The disclosure content of this document is fully incorporated herein as far as the description of a design of the contact glass 45 possible for the treatment device 1 is concerned. The treatment device 1 optionally further has a camera (not shown) which can record an image of the cornea 17 through the contact glass 45.The illumination for the camera can be in both the visible and infrared spectral range.

[0106] The control unit 11 of the treatment device 1 has a planning device 16, which will be explained in more detail later and which comprises a data memory and a calculation device which calculates the cutting surface(s) and / or control data, in particular control data for the treatment device 1, in preparation so that the cutting surface(s) can be created in the surgical procedure. Control data can be concrete control values ​​for the focus position adjustment mechanism 8, e.g., for a z-scanner 8a and for an xy-scanner 8b. The control data are output by the control unit 11 as control signals for the corresponding drives of the focus position adjustment mechanism 8. However, the control data can also be predetermined coordinates of target points, as well as the sequence of these target points, on which the laser radiation is to be focused, at a quasi-higher control level.The control data may in particular comprise one or more trajectories^) along which the focus position is to be adjusted.

[0107] Fig. 2 schematically shows the mode of operation of the incident laser beam 6. The laser beam 6 falls as a focused laser beam 7 into the cornea 17 of the eye 2. A schematically drawn optics 18 is provided for focusing. It creates a focus 19 in the cornea 17, in which the laser radiation energy density is so high that, in combination with the pulse length of the pulsed laser radiation 6, a non-linear effect occurs in the cornea 17. For example, each pulse of the pulsed laser radiation 6 in the focus 19 can create an optical breakthrough in the cornea 17, which in turn initiates a plasma bubble, which is only schematically indicated in Fig. 2. When the plasma bubble forms, the tissue layer separation covers a larger area than the focus 19, although the conditions for creating the optical breakthrough are only achieved in the focus 19. In order for each laser pulse to create an optical breakthrough, the energy density, i.e.The fluence of the laser radiation must be above a certain, pulse-length-dependent threshold. This relationship is known to the person skilled in the art, for example, from DE 695 00 997 T2. However, the type of tissue separation used by the treatment device 1 is not further relevant to the following description; what is essential is merely that a cut surface is created in the cornea 17 of the eye 2.

[0108] Several elements are relevant for the imaging properties of eye 2, one of which is the curved cornea 17 of eye 2. The front of the cornea 17 refracts the light rays due to its curvature, which is why the radius of curvature of the cornea is particularly relevant for the imaging properties of eye 2. In the case of a visual defect, the focus of a parallel incident bundle of light rays is not on the retina of eye 2 due to a (to be corrected) visual defect in the form of myopia or hyperopia, but in front of or behind it. Other visual defects, such as astigmatism, lead to a non-point-shaped focus. Still other visual defects cause a visual defect that depends on where the focus is on the retina. Such visual defects are described as a whole by visual defect data.The refractive error is corrected by modifying the front of the cornea (particularly its curvature) in such a way that this specifically leads to a change in the refractive properties of the cornea 17. Due to the modification of the front of the cornea 17 to the new front, the focus is shifted or changed in such a way that the preoperatively existing refractive error is corrected.

[0109] In order to perform an ophthalmic surgical refractive correction, a piece of tissue, known as a lenticule, can be removed from an area within the cornea 17 using laser radiation 6. This is done by separating tissue layers within the cornea 17, isolating the piece of tissue within the cornea 17 and then enabling its removal. The piece of tissue is delimited by a three-dimensionally shaped cutting surface or several three-dimensionally shaped cutting surfaces. For this purpose, in the case of pulsed laser radiation, the position of the focus 19 of the focused laser radiation 7 is adjusted three-dimensionally within the cornea 17. This is shown schematically in Fig. 3a, Fig. 3b and Fig. 4. The curvature of the front side of the cornea 17 is specifically changed by removing the lenticule in order to achieve the refractive correction.A uniformly thick piece of tissue would not significantly change the curvature of the front of the cornea - hence the term lenticule.

[0110] In Fig. 3a and 3b, the elements of the treatment device 1 are shown only to the extent that they are necessary for understanding the creation of the cutting surface. The laser beam 6 is, as already mentioned, bundled into a focus 19 in the cornea 17, and the position of the focus 19 in the cornea 17 is adjusted so that, to create the cutting surface, focused energy from laser radiation pulses is introduced into the tissue of the cornea 17 at various points. The laser radiation 6 is preferably provided by the laser source 5 as pulsed radiation. The scanning device 8 is constructed in two parts according to Fig. 3 (the y-direction is perpendicular to the plane of the drawing in Fig. 3) and comprises a z-scanner 8a and an xy-scanner 8b.

[0111] The z-scanner 8a is designed for adjusting the depth of field (focus position in the z-direction) and is designed, for example, as an adjustable telescope. The z-scanner 8a ensures that the z-position of the focus 19, i.e., its position in the direction of the optical axis of incidence, is changed.

[0112] In the described embodiment, the xy scanner 8b comprises two essentially orthogonally deflecting galvanometer mirrors and deflects the laser beam 6 coming from the z scanner 8a two-dimensionally (in the xy plane), so that a deflected laser beam is present after the scanning device 8. The scanners 8a and 8b, for example, shift the focus 19 along a three-dimensional path along which the laser pulses are emitted to form the cutting surface^).

[0113] The z-scanner 8a can be arranged downstream or upstream of the xy-scanner 8b.

[0114] In Figure 3b the scanning device 8 is shown in somewhat more detail.

[0115] Thus, a pupil optics 118 is arranged in the beam path between the two galvanometer mirrors 109, 109'. This optics has two converging lenses 119 and 119' that project the image of the galvanometer mirror 109 first struck by the beam 6 onto the other galvanometer mirror 109'. A real intermediate image is created in air between the converging lenses 119 and 119' to prevent optical penetrations in components of the scanner 8 or the scanning device 8. This results in a fixed position of the pupil, which facilitates a favorable design of the focusing optics 108. Furthermore, by imaging the two galvanometer mirrors 109, 109' into each other, the size of the galvanometer mirror 109' can be kept small. In the example, the mirrors are shaped like an ellipse, with a major and minor axis length of approximately 21 mm and 15 mm, respectively. An associated actuator 110, 110' is provided for each galvanometer mirror 109, 109'.

[0116] The focusing optics 108 has an entrance lens 120 into which the laterally deflected beam 6 emerging from the xy scanner 8b enters and is focused in a real intermediate image, a tube lens 121 which images the intermediate image towards infinity depending on its position, a beam splitter 116 arranged downstream of the tube lens 121 in the beam path, which beam splitter deflects the beam 6 onto the exit lens 115, and the exit lens 115 which then focuses the beam 6, which is parallel or only slightly convergent or slightly divergent at this point, into the cornea 117 of the eye 2 according to its fixed focal length and thus functions as an objective lens.

[0117] The beam splitter 116 is designed such that observation beams 117, which are created by imaging points in the cornea 17 of the eye 2 through the exit lens 115 toward infinity, pass through the beam splitter 116 and can be guided to a tube with an eyepiece (not shown in Fig. 3b) or a lens with a camera (not shown in Fig. 3b). This enables simultaneous observation during treatment of the cornea with the beam 6.

[0118] The division of the focusing optics 108 into an entrance lens 120, a tube lens 121, and an exit lens 115 or a main lens 115 has the advantage, in addition to enabling an interface for co-observation, that small beam diameters can be realized at the entrance of the focusing optics 108. For example, the beam diameter can be 15 mm, so that the two galvanometer mirrors 109, 109' with a working diameter of 15 mm can be used. This relatively small size of the two galvanometer mirrors 109, 109' is advantageous for achieving high scanning speeds. Furthermore, the division of the focusing optics into subsystems enables diffraction-limited correction of the focusing optics. Since the beams between the subsystems do not need to be corrected, compensation effects can be utilized, significantly reducing the number of required lenses.

[0119] To avoid undesired interactions, all optical components in this and the other embodiments can be designed in such a way that all real intermediate images are in air and thus even very intense laser radiation cannot lead to optical breakdowns in optical components.

[0120] In the embodiments described so far, the entire optical system of the scanning device 8, in particular the input and focusing optics, is chromatically corrected for the spectral width of a fs pulse to be used. Through adapted dispersion management before the pulse enters the system and the aforementioned chromatic correction of the entire optical system, a pulse duration can be achieved at the focus that, due to dispersion, i.e., due to chromatic aberrations, is less than 30% longer than the theoretically achievable pulse duration.

[0121] Furthermore, the lens 111 of the z-scanner 8a, which also includes the lens 112 and is movable by means of the actuator 114, can be moved relative to the lens 112 over such a large distance that the focus of the beam can be moved in the beam direction within a range greater than 0.5 mm. Furthermore, the scanning device 8 (or the deflection device 8) is designed such that the focus of the beam can be moved within a range in a lateral plane that has a diameter of 8 mm to 11 mm.

[0122] The laser, the input optics, and the focusing optics are designed so that the focused beam has a diameter of less than 5 micrometers at the focus. In the exemplary embodiments, the focusing optics preferably have an aperture greater than 0.30.

[0123] The laser surgical systems are therefore suitable, for example, for cutting lenticules in the cornea and / or for forming a foldable corneal flap.

[0124] For the functional principle of the treatment device 1, the assignment of the individual coordinates to the spatial directions is not essential, nor is it important that the xy scanner 8b deflects around mutually perpendicular axes. Rather, any scanner can be used that is capable of adjusting the focus 19 in a plane in which the axis of incidence of the optical radiation does not lie. Two-stage scanner setups, as known from WO 2017 / 00581 15 A1, can also be used. In addition, any non-Cartesian coordinate system can be used to deflect or control the position of the focus 19. Examples of these are spherical coordinates or cylindrical coordinates. The position of the focus 19 is controlled by means of the scanners 8a, 8b under the control of the control unit 11, which makes corresponding settings on the laser source 5, the modulator 9 (not shown in Fig. 3), and the scanner 8.The control unit 11 ensures appropriate operation of the laser source 5 as well as the three-dimensional focus adjustment described here as an example, so that ultimately a desired cutting surface or several desired cutting surfaces are formed that isolate a specific piece of corneal tissue that is to be removed or harvested for refraction correction. The control unit 11 operates according to predefined control data.

[0125] The control data is specified, for example, as target points for the focus adjustment and / or as data for the specified path. The control data is generally summarized in a control data set. This specifies geometric specifications for the cutting surface to be created, for example, the coordinates of the target points as a pattern. In this embodiment, the control data set also contains specific control values ​​for the focus position adjustment mechanism, e.g., for scanner 8. The control data is based on control data that specify the cutting surface(s) to be created, as will be explained below.

[0126] The creation of the incision surface(s) with the treatment device 1 is shown as an example in Fig. 4. A piece of corneal tissue 21 in the cornea 17 is isolated by adjusting the focus 19, into which the focused beam 7 is bundled. At least one incision surface is formed, which can also be multi-part, which is why it is also referred to as "incision surface(s)." In this example, it has an anterior lenticule incision surface 22, a posterior lenticule incision surface 23, and an edge incision surface 24 connecting both lenticule incision surfaces 22, 23. These terms are to be understood merely as examples and are chosen in reference to the conventional LASIK procedure. Depending on the surgical procedure, the cutting surfaces 22 and 23 and, if necessary, the edge cutting surface 24, which joins the cutting surfaces 22 and 23 at their edges where necessary, delimit and isolate the piece of corneal tissue 21. Through an opening incision 25 (orThe piece of corneal tissue 21 can be removed via the opening incision surface 25, as provided for in the aforementioned SMILE procedure.

[0127] Fig. 5 shows a schematic view of the treatment device 1, and the significance of the planning device 16 will be explained in more detail based on this. In this variant, the treatment device 1 has at least two devices or modules. The laser device 4 already described emits the laser beam 6 onto the eye 2 (which is not shown in Fig. 5). As already described, the laser device 4 is operated fully automatically by the control unit 11, i.e. the laser device 4 starts generating and deflecting the laser beam 6 upon a corresponding start signal and creates cutting surfaces that are constructed in the manner described. The laser device 4 receives the control signals required for operation from the control unit 11, to which corresponding control data have previously been made available. This takes place, for example, by means of the planning device 16, which is shown in Fig. 5 merely as an example as a component of the control unit 11.Of course, the planning device 16 can also be designed independently and communicate with the control device 11 via a wired or wireless connection. In this case, it is only essential that a corresponding data transmission channel is provided between the planning device 16 and the control device 11.

[0128] The planning device 16 comprises, as its core element, a calculation device 16a, which, as explained below, calculates the cutting surface(s) to be created in the cornea 17 and determines the data required for these cutting surfaces. The calculation device 16a can have a processor 16a1 and a memory 16a2. The planning device 16, or directly the calculation device 16a, generates the control data set therefrom, which is made available to the control unit 11 for carrying out the ophthalmic refractive correction.

[0129] To calculate the cut surface(s), the calculation device 16a uses measurement data about the cornea of ​​the eye. In the embodiment described here, these measurement data originate from a measuring device 28 that previously measured the eye 2 of the patient 2. Of course, the measuring device 28 can be configured in any desired manner and transmit the corresponding measurement data to the interface 29 of the planning device 16.

[0130] The planning device 16 supports the operator of the treatment device 1 in determining the cutting surface(s) 22-25 for isolating the corneal tissue piece 21. This can extend to a fully automatic determination of the cutting surface(s) 22-25, which can be effected, for example, by the calculation device 16a determining the corneal tissue piece 21 to be removed from the measured data, defining its boundary surface^) as the cutting surface(s), and generating corresponding control data for the control unit 11 therefrom. At the other end of the degree of automation, the planning device 16 can provide input options where a user enters the cutting surface(s) 22-25 in the form of geometric parameters, etc. Intermediate stages provide suggestions for the cutting surfaces, which the planning device 16 automatically generates and which can then be modified by an operator.In principle, all those concepts that have already been explained in the more general description section above can be applied here in the calculation device 16a.

[0131] Fig. 6 shows a block diagram for determining the data for generating a cutting surface (e.g., for correcting a refractive error). In a step V1, refractive error data of the eye is received, which indicates the refractive correction required for the eye. This data can, for example, be provided in a preceding step, which can in particular include measuring the eye. On the basis of this refractive correction requirement, the volume of the piece of tissue to be removed from the cornea is determined in a step V2. Since the thickness profile is of crucial importance for the correction of a refractive error (cf. explanations for Fig. 4), there is still no concrete definition of the piece of tissue. In a step V3, the piece of tissue, i.e. the lenticule to be isolated in the cornea, is calculated. In a final step V4, the cutting surface or surfaces (e.g., 22, 23, 24 and, if applicable,25) is calculated, which is required to isolate the lenticule 21 in the cornea 17. For this cutting surface(s), corresponding control data is generated in a step V5. This data then serves as control data for the treatment device 1, whereby it may well be the aforementioned data at a higher control level (definition of paths along which the focus is adjusted and / or coordinates of target points), which are then converted—possibly only during operation of the treatment device 1—into corresponding control data for the treatment device 1.

[0132] The desired cutting surfaces 22-25 are preferably generated such that the focused beam 7 is guided by the scanner 8 in at least one spiral path along the desired cutting surface 22-25. The pulse frequency of the laser radiation 7 and the scanning speed of the scanner 8 are coordinated such that the laser foci 19 (hereinafter also referred to as laser spot 19 or spot 19) are generated spaced apart from one another in the cornea 17. The distance between two foci 19 directly adjacent along the spiral path is referred to below as spot distance dS or focus distance dS. Furthermore, the radial distance of the spiral path is referred to as track distance dB or track distance dB.

[0133] Figure 7 shows a single spiral path 30 projected onto the xy plane. The change in the z coordinate for forming, for example, a spherical surface is not shown here. Furthermore, a scanning direction 50 along which the laser radiation 7 is guided to generate the spots 19 (five spots 19, for example), the spot spacing dS, and the path spacing dB are shown. Of course, 30 spots 19 are generated along the entire spiral path; these spots are not shown for simplicity of illustration.

[0134] In Figure 8, instead of the spiral path, five concentric circles 311, 312, 313, 314, and 315 are shown, along which the laser beam 7 can be guided to create the desired cutting surface. Five spots 19, the scanning direction 50, the spot spacing dS, and the path spacing dB are shown as examples, in the same way as in Figure 7. Of course, spots 19 are generated on the entire circles 311-315; these spots are not shown for the sake of simplicity.

[0135] Circles 311 - 315 do not have to be concentric. Furthermore, a non-circular annular path shape can also be present, which is preferably closed but can also be open.

[0136] To create the lenticule cut surfaces 22, 23, the spots 19 are guided, for example, along the spiral path shown in Figure 7. This process currently requires approximately 30 seconds to 1 minute. This depends, among other things, on the pulse frequency of the laser source 5, the deflection speed that can be generated using the z-scanner 8a and the xy-scanner 8b (and thus the path speed with which the laser focus 19 can be moved in the tissue), as well as the desired spot spacing dS and the desired path spacing dB.

[0137] The treatment device 1 according to the invention is designed to provide two operating modes, namely a basic mode and a second operating mode, with which the lenticule cut surfaces 22, 23 can be produced more quickly. The second operating mode is therefore also referred to below as the fast operating mode. In the basic mode, the treatment device 1 operates as described, with the spot spacing dS and the track spacing dB being adjustable, for example.

[0138] In fast operating mode, the laser beam 6 is split into at least three partial beams by pivoting or retracting a beam splitter 33 into the beam path, so that at least three individual (preferably closely adjacent) partial spots are simultaneously focused in the cornea 17. Preferably, four spots are generated.

[0139] Figs. 3a and 3b schematically show the beam splitter 33. The dashed line indicates that the beam splitter 33 is retracted into the beam path. This is the fast operating mode of the treatment device 1. The solid line shows that the beam splitter 33 is positioned outside the beam path and thus does not effect beam multiplication. This is the basic mode of the treatment device 1. An actuator 33i (e.g., a stepper motor) can be provided to move the beam splitter 33.

[0140] The beam splitter 33 can preferably be positioned in the beam path between the laser source 5 and the z-scanner 8a. The beam splitter 33 can preferably be positioned directly in front of the z-scanner and / or in the collimated beam path.

[0141] The spacing of the partial spots is preferably only slightly larger than their diameter. For a partial spot diameter of, for example, 3 pm, the beam splitter 33 generates a partial spot spacing of less than or equal to 15 pm. The partial spot spacing is thus less than or equal to 5 times the partial spot diameter itself. The partial spot spacing can be approximately 3 pm to 5 pm, and in particular less than 10 pm.

[0142] Due to the positioning of the beam splitter 33 in the collimated beam path, the beam splitter 33 is designed such that the partial beams emerging from the beam splitter 33 are not parallel to one another. In particular, their propagation directions can be such that they are all different and each enclose an angle other than 0° with the direction of the collimated beam path. These different propagation directions then lead to different positions of the partial spots 19 in the xy plane. Advantageously, there is no common plane in which all partial beams lie. The angle between two partial beams can, for example, lie in the xz plane, and the angle between two other partial beams can lie in the yz plane.

[0143] In this fast operating mode, a spiral track 30 can be realized, whereby the track spacing dB as well as a partial spot pattern spacing dM1 , as shown in Figures 9 to 11, can each be selected to be approximately twice as large as a spacing dT of the partial spots 19i , 192, 193, 194. The partial spots 19i , 192, 19s, 194 maintain a fixed spatial arrangement relative to one another in the xy coordinate system at the eye 2.

[0144] As can be seen from Figures 9 to 11, the partial spot spacing dT (hereinafter also referred to as the minimum partial beam spot spacing dT) of a partial spot pattern 34 (hereinafter also referred to as the spot pattern 34) is the minimum spacing between two of the partial spots 19i, 192, 19s, 194 (and 19s and 19e in Fig. 11). Furthermore, the maximum partial beam spot spacing dE is shown, which is the maximum spacing between two partial spots 19i, 192, 19s, 194 (and 19s and 19e in Fig. 11) of a spot pattern 34.

[0145] The distance between two spot patterns 34 along the scanning direction 50 is called the first pattern distance dM1, and the distance between two spot patterns 34 perpendicular to the scanning direction 50 is called the second pattern distance dM2. The pattern distances can be measured, for example, to the center point 35 of the spot patterns 34.

[0146] A spot pattern 34 is formed by the simultaneously generated partial spots 19i, 192, 19s, 194. The dashed connecting lines and center points are for illustrative purposes only.

[0147] In Figures 9 and 10, the partial spots 19i, 192, 19s, 194 of a partial spot pattern 34 lie on the corners of a square, as indicated by dashed lines, and the centers 35 of the partial spot patterns 34 lie on the spiral path 30.

[0148] In this way, the centers 35 of the partial spot patterns 34 have, for example, a first and second pattern spacing dM1, dM2 and a track spacing dB of 10 pm each, if the partial spots 19i, 192, 19s, 194 themselves have a partial spot spacing dT of 5 pm from one another. The maximum partial beam spot spacing dE is approximately 7.1 pm.

[0149] In Figure 11, the partial spots 19i, 192, 19s, 194, 19s, and 19e of a partial spot pattern 34 are located at the corners of a hexagon. With a partial spot spacing dT of 5 pm, the first and second pattern spacing dM1, dM2, and the track spacing dB can each be 15 pm. The maximum partial beam spot spacing dE is 10 pm.

[0150] In a variation not shown, a partial spot can also be located at the center point 35, so that the partial spot pattern 34 comprises seven partial spots. The constant path spacing dB is evident in the spiral path 30 shown in Figure 7. The laser spots 19 are placed at a fixed spacing along this path, as shown schematically in Figure 7.

[0151] For the fast mode, according to the invention, for example, four partial spots 19i, 192, 19s, 194 are generated, which are located at the corners of a square. The associated spiral paths on which the corners of the partial spot pattern 34, and thus the partial spots 19i, 192, 19s, and 194, move are shown in Figure 12, with the center point 35 of the partial spot pattern 34 being moved along the spiral path 30 (shown as a solid line in Figure 12). In Figure 12, the spiral paths S2 and S4 (dotted curves S2 and S4) show the movement of the partial spots 192 and 194. The spiral paths S1 and S3 (dashed curves S1 and S3) show the movement of the partial spots 19i and 19s.

[0152] It is now evident that the spiral paths S2 and S4 of the upper and lower partial spots 192 and 194 intersect near the x-axis, respectively, and that the spiral paths S1 and S3 of the right and left partial spots 19i and 19s intersect near the y-axis.

[0153] The resulting overall spot pattern is very homogeneous along the scan direction 50. Due to the selected path spacing dB, the homogeneity across the scan direction 50 is lower, which may well be desirable.

[0154] Figure 13 schematically shows that an overlay or overlap of partial spots can be avoided by a suitable partial spot pattern distance dM1 in the scanning direction 50.

[0155] If the first partial spot pattern distance dM1 corresponds to twice the partial spot distance dT and the track distance dB or the second partial spot pattern distance dM2 corresponds to twice the partial spot distance dT, a very homogeneous overall spot pattern is created (both along and across the scan direction 50), as shown in Figure 14. This is a preferred choice of distances for a spot pattern with four partial beam spots located at the corners of a polygon with four corners (in particular, a rectangle, a parallelogram, a rhombus, or a square).

[0156] In particular, the first partial spot pattern distance dM1 can correspond to n times the partial spot distance dT and the track distance dB or the second partial spot pattern distance dM2 can correspond to n times the partial spot distance dT, where n can be greater than or equal to 1.5 and less than or equal to 3. These distance relationships apply to spot patterns 34 that only have two partial spots each along the scanning direction and transversely to the scanning direction. However, one can also define a first scanning distance dL1 as the minimum distance between two partial spots of two spot patterns 34 directly adjacent along the track 30 and a second scanning distance dL2 as the minimum distance between two partial spots of two spot patterns 34 directly adjacent transversely to the track 30, as shown in Figs. 9 to 11. In this case, it is preferred if the first scan distance dL1 corresponds to m times the partial spot distance dT, where m is greater than or equal to 0.5 and less than or equal to 2.Furthermore, the track spacing dB can be selected such that the second scan spacing dL2 corresponds to m times the partial spot spacing dT, where m is greater than or equal to 0.5 and less than or equal to 2. These spacing ratios apply to spot patterns 34 that each have two or more partial spots along the scan direction and transverse to the scan direction.

[0157] It can be seen that although the paths on which the partial spots 19i, 192, 19s, 194 lie intersect, the partial spots 19i, 192, 19s, 194 themselves are approximately isotropic, or approximately uniformly distributed. According to the invention, the partial spot pattern 34 remains fixed in an xy coordinate system and moves along a spiral path 30 or Archimedean spiral 30.

[0158] According to the invention, the square partial spot pattern 34 is achieved by the beam splitter 33 positioned in the beam path, which effects the desired beam multiplication, for example by means of birefringence.

[0159] Birefringence is understood here specifically as the splitting of a light beam into two beams when passing through an optically anisotropic body. These beams propagate independently of each other at different speeds of light. One beam propagates according to Snell's law of refraction and is called an ordinary ray; the other beam does not follow this law and is called an extraordinary ray.

[0160] Both beams are linearly polarized, since only linearly polarized waves can propagate in an anisotropic medium. The polarization directions of the ordinary and extraordinary beams are perpendicular to each other.

[0161] There are materials that are inherently birefringent. However, there are also materials or substances that are initially optically isotropic in every direction and only become anisotropic under external influences, such as mechanical pressure or electric and / or magnetic fields. For example, there are electro-optical effects (e.g., the Kerr effect), in which an optically isotropic medium exhibits optical birefringence when an electric field is applied, and magneto-optical effects (e.g., the Cotton-Mouton effect), in which the birefringence is induced by the application of a magnetic field.

[0162] Figure 15 shows a first birefringent element 40, designed as a Wollaston prism. It comprises two rectangular prisms 40i, 402 (e.g., calcite prisms) cemented together at their base surfaces. The crystal-optical axes of the two prisms 40i, 402 are perpendicular to each other. The double arrows indicate a first linear polarization (e.g., p-polarization), and the filled circles indicate a second linear polarization (e.g., s-polarization), which is perpendicular to the first linear polarization. The polarization of the incident linearly polarized light can be vectorially decomposed into these two components.

[0163] In the Wollaston prism, the incident linearly polarized laser beam 6 is split into two perpendicularly polarized partial beams 61 and 62, which are refracted at equal, opposite angles from the direction of incidence. One can also say that the two partial beams 61 and 62, which lie in the xz-plane (first plane), diverge in a first splitting direction (here, along the x-axis), which lies in the xz-plane.

[0164] In the illustration in Fig. 15, it was assumed that the polarization direction of the linearly polarized laser beam 6 is rotated by 45° to the direction of the first linear polarization and by 45° to the direction of the second linear polarization.

[0165] If a second birefringent element 41 is arranged downstream of the first birefringent element 40 in a suitable manner, each of the two partial beams 61 and 62 is split again into two partial beams lying in the yz plane (second plane) in a second splitting direction (e.g. in the direction of the y-axis), so that four partial beams 611, 612, 621 and 622 are then present. This is shown in a schematic exploded view in Figure 16, wherein a Wollaston prism is provided as the first and second birefringent element 40, 41. The first interface 42 in the first birefringent element 40 is rotated by 90° about the z-axis relative to the second interface 43 in the second birefringent element 41. Thus, the first interface 42 is inclined in the xz plane and the second interface 43 is inclined in the yz plane.

[0166] One can also say that the first birefringent element 40 splits the beam in a first splitting direction (e.g., along the x-axis) and that the second birefringent element 41 splits the beam in a first splitting direction (e.g., along the y-axis), so that the two splitting directions are rotated or turned 90° relative to each other around an imaginary axis parallel to the propagation direction of the laser beam 6. The same angle then exists between the two planes (xz plane and yz plane).

[0167] Between the two birefringent elements 40 and 41, a waveplate 44 with a thickness of 2 mm (for rotating the polarization direction by 45°) is arranged. This waveplate is rotated by 22.5° around the z-axis so that the desired beam splitting can be achieved by the second birefringent element 41. The waveplate 44 could also be an M4 plate with an angle of 45°. In this case, the (linear) polarization would not be rotated by 45°, but rather the linear polarization would be converted into circular polarization.

[0168] In Figure 16, the four partial beams 6n, 612, 621, and 622 are shown as parallel partial beams 611, 612, 621, and 622 for simplicity. In fact, they have different angles relative to the direction of the incident laser beam 6. The angles lie in two different planes. The spots form a surface.

[0169] In a modification, shown as a schematic exploded view in Fig. 17, the two prism elements 402 and 411 can be formed as a single-piece central prism element 46, wherein, with a suitable choice of the position of the crystal axes of the central prism element 46 and the two other prism elements 40i, 412, the 7 / 2 layer can be omitted. The beam splitter 33 then comprises a prism or a prism arrangement with three prism elements 40i, 46, and 412. The two prism elements 40i, 412 can be 90° prisms, and the central prism element 46 can be oblique. The central prism element 46 can also be isotropic.

[0170] In a modification of the structure of Fig. 17, shown as a schematic exploded view in Fig. 18, the two prism elements 402 and 411 can be manufactured as separate elements, which are already connected in the illustration of Fig. 18. This facilitates the manufacture of the beam splitter 33.

[0171] The first splitting into the partial beams 61 and 62 can occur upon entry into the central prism element 46 (e.g., upon passing through the interface 46i of the central prism element 46). The second splitting into the partial beams 611, 612, 621, and 622 can then occur upon entry into the third prism element 412 (e.g., upon passing through the interface 43 of the third prism element 412).

[0172] The elements shown in Figures 16 to 18 can be cemented together. Instead of the Wollaston prism design, the Rochon prism, Senarmont prism, or Nomarski prism can also be chosen.

[0173] A further advantage of such a polarization-optical arrangement 33 is that at least two partial beams have different polarizations. This ensures, particularly in the case of closely spaced partial spots 19, that the light from different partial spots cannot interact with each other and does not interfere, thus creating better-separated, isotropic partial spots.

[0174] In the described embodiment, the incident beam 6 is split into four sub-beams 6n, 612, 621, and 622, whose center points propagate in the same or approximately the same direction as the incident beam 6. In this way, the beam path remains unchanged in both basic and fast modes. No further changes or switching are required at other points in the beam path.

[0175] A corresponding quadrupling of the laser power of the laser source for the incident beam 6 is sufficient to ensure that the same pulse energy is present in each of the four partial spots as in the basic mode.

[0176] The design of the beam splitter 33 and, in this case, the two prisms 40 and 41 determines the partial spot spacing dT. Depending on the focal length of the scanning optics 8, a partial spot spacing of dT = 3 pm can be achieved, for example, by setting an angle of 2' (or 2 minutes) between the partial beams 611, 612, 621, and 622. The corresponding track and center distances dB and dM are then selected at approximately 6 pm, which doubles the scanning speed and thus halves the treatment time compared to the spot and track distance dS and dB of 3 pm.

[0177] It is possible to provide various beam splitters 33, each of which can be selectively inserted into the beam path. This allows for various fast modes to be realized. The pivoting or retraction of the (respective) beam splitter 33 can be motorized, e.g., with a stepper motor 33i. The beam splitter 33 can be retracted before the start of treatment, and the beam splitter 33 can remain in this position throughout the entire treatment (e.g., as shown in Figure 4).

[0178] The beam splitter 33 can be positioned directly in front of the z-scanner 8a. There, the beam diameter is still small, and all components monitoring the scanning process, such as power control sensors or similar, remain unaffected.

Claims

Patent claims 1. An ophthalmological laser therapy system for treating a patient's eye, comprising a laser device (4) for emitting a pulsed laser beam (6), a beam splitter (33) for generating a plurality of pulsed partial beams from the pulsed laser beam (6), a scanning device (8) for moving the pulsed partial beams along a scanning direction, a control device (11) for controlling the scanning device (8), and a focusing device (108) for focusing the pulsed partial beams into the patient's eye (2) as partial beam spots (19i, 192, 19s, 194) arranged in a spot pattern (34), wherein the control device (11) controls the scanning device (8) such that two spot patterns (34) directly adjacent along the scanning direction are spaced apart from one another.

2. Ophthalmic laser therapy system according to claim 1, wherein the scanning device guides the spot pattern in an unchanged orientation along a predetermined path.

3. Ophthalmological laser therapy system according to claim 1 or 2, wherein a minimum partial beam spot spacing (dT) is present in the spot pattern (34), and wherein the control device controls the scanning device such that a minimum first scanning spacing of two spot patterns (34) directly adjacent along the scanning direction is greater than or equal to 0.5 times the minimum partial beam spot spacing and less than or equal to 2 times the minimum partial beam spot spacing, wherein the minimum first scanning spacing is the minimum spacing of two partial beam spots along the scanning direction of directly adjacent spot patterns (34).

4. Ophthalmological laser therapy system according to one of the above claims, wherein the control device (11) controls the scanning device (8) such that two spot patterns (34) directly adjacent to one another transversely to the scanning direction are spaced apart from one another.

5. Ophthalmological laser therapy system according to one of the above claims, wherein in the spot pattern (34) there is a minimum partial beam spot distance (dT), and wherein the control device controls the scanning device such that a minimum second scanning distance of two spot patterns directly adjacent transversely to the scanning direction is greater than or equal to 0.5 times the minimum partial beam spot distance and less than or equal to 2 times the minimum partial beam spot distance, where the minimum second scan distance is the minimum distance between two partial beam spots transverse to the scan direction of directly adjacent spot patterns.

6. Ophthalmological laser therapy system according to one of the above claims, wherein the beam splitter (33) has a first birefringent element which generates two pulsed partial beams from the pulsed laser beam (6) by means of birefringence.

7. Ophthalmic laser therapy system according to claim 6, wherein the beam splitter (33) has a second birefringent element arranged downstream of the first birefringent element, wherein the first birefringent element splits the pulsed laser beam into a first and a second pulsed partial beam and wherein the second birefringent element splits the first pulsed partial beam into a third and fourth pulsed partial beam and the second pulsed partial beam into a fifth and sixth pulsed partial beam, so that four pulsed partial beams emanate from the second birefringent element.

8. Ophthalmic laser therapy system according to claim 7, wherein the first birefringent element splits the incident beam into the first and second partial beams such that they lie in a first plane and diverge in this plane, wherein the second birefringent element splits an incident beam into two partial beams such that they lie in a second plane and diverge in this plane, and wherein the second birefringent element is rotated relative to the first birefringent element about an axis parallel to the direction of the incident beam such that the two planes enclose an angle in the range of 70° - 1 10°.

9. Ophthalmic laser therapy system according to claim 7 or 8, wherein a V2 plate and / or a V4 plate is arranged between the two birefringent elements.

10. Ophthalmological laser therapy system according to one of claims 7 to 9, wherein a V2 plate and / or a V4 plate is arranged in front of the first birefringent element, through which the pulsed laser beam (6) passes before it strikes the first birefringent element. 1 1. Ophthalmic laser therapy system according to one of the above claims, in which the beam splitter has three partial prisms with two inner interfaces, at least two partial prisms have a birefringent crystal, wherein the crystal axes of the birefringent crystals have different orientations.

12. Ophthalmological laser therapy system according to one of the above claims, in which four partial beams are generated by means of the beam splitter (33), which partial beams lie on the corners of a polygon, in particular on the corners of a rectangle, a rhombus or a square.

13. Ophthalmological laser therapy system according to one of the above claims, wherein the scanning device guides the spot pattern in a predetermined plane or a projection onto the predetermined plane along a spiral path (30) and / or along at least one annular path (30i, 302, 30s, 304, 30s).

14. An ophthalmic laser therapy system according to any one of the above claims, wherein the scanning device guides the spot pattern in an unchanged form along a predetermined path.

15. Ophthalmological laser therapy system according to one of the above claims, wherein the partial beams have non-parallel propagation directions upon exiting the beam splitter (33).

16. Ophthalmological laser therapy system according to one of the above claims, in which the partial beam spots (19i, 192, 19s, 194) serve to produce a cut surface in the patient's eye (2).

17. Ophthalmological laser therapy system according to one of the above claims, in which the scanning device (8) has a z-scanner (8a) and the beam splitter (33) is arranged or positionable between the laser device (4) and the z-scanner (8a), in particular as the last element in front of the z-scanner (8a).

18. Ophthalmological laser therapy system according to one of the above claims, wherein the beam splitter (33) is arranged or positionable in a collimated beam path of the pulsed laser beam (6).

19. Ophthalmic laser therapy system according to one of the above claims, wherein the beam splitter (33) generates the partial beams such that they have equal pulse energies.

20. Ophthalmological laser therapy system according to one of the above claims, wherein the beam splitter (33) generates the partial beams such that the pulses of the individual partial beams are present simultaneously.

21. Ophthalmological laser therapy system according to one of the above claims, wherein the beam splitter (33) generates at least three partial beams such that the partial beam spots (19i, 192, 193, 194) of the spot pattern (34) delimit an area.

22. Device for generating control data for generating at least one cut surface in a patient's eye, comprising an interface (29) for receiving data for the cut surface to be generated, a calculation device (16a) connected to the interface (29) and configured - to receive the data for the cutting surface to be created and - for calculating the control data for a scanning device (8) in order to be able to generate the cutting surface with partial beam spots (19i, 192, 19s, 194) arranged in a spot pattern, which are moved by means of the scanning device (8) along a scanning direction in the patient's eye (2), in such a way that two spot patterns (34) directly adjacent along the scanning direction are spaced from one another.

23. A method for generating control data for generating at least one cut surface in a patient’s eye, comprising - Receiving data for the cutting surface to be created and - Calculating the control data for a scanning device (8) in order to be able to generate the cutting surface with partial beam spots (19i, 192, 19s, 194) arranged in a spot pattern, which are moved by means of the scanning device (8) along a scanning direction in the patient's eye (2), in such a way that two spot patterns (34) directly adjacent along the scanning direction are spaced from one another.

24. A computer program product comprising program code which, when loaded into a computer, carries out a method according to claim 23.

25. Beam splitter (33) for a laser therapy system, wherein the beam splitter has a first birefringent element which splits an applied laser beam into a first and a second partial beam, wherein the beam splitter further has a second birefringent element arranged downstream of the first birefringent element, wherein the second birefringent element splits the first partial beam into a third and fourth partial beam and the second partial beam into a fifth and sixth partial beam, so that four partial beams emanate from the second birefringent element.

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