Devices and methods for generating control data with an optimized cutting geometry for access cuts during a correction of the refraction of an eye

Abstract

The present invention relates to a planning unit, an ophthalmic laser therapy device, and a planning method for generating control data with an optimized cutting geometry for access cuts when correcting the refraction of an eye with a main optical axis and a cornea through corneal modification within the corneal tissue. The method comprises receiving data representing a refraction correction requirement, calculating a corneal tissue volume to be removed, and calculating cutting surface data, wherein the cutting surface data includes cap cutting data, lenticule cutting data, lateral cutting data, and access cutting data.The access cut data represents a first access cut and a second access cut, wherein the cutting surface data further comprises side surface segment cutting data representing a side surface segment and at least one cutting parameter modification to be used therein. The present invention further relates to a computer program product, a data signal, and a computer-readable non-volatile storage medium.

Description

[0001] The present invention relates to a planning unit, an ophthalmological laser therapy device and a planning method for generating control data with an optimized cutting geometry for access cuts when correcting the refraction of an eye with a main optical axis and a cornea by corneal modification within the tissue, wherein the ophthalmological laser therapy device comprises a laser device, a focusing device, a scanning device and a control unit, and wherein the planning unit comprises a device for data processing which is designed to receive data representing a refraction correction requirement, to calculate a tissue volume of the cornea to be removed, wherein the calculation is carried out on the basis of the refraction correction requirement, and to calculate cutting surface data which represent a cutting surface delimiting the tissue volume.The sectional area data includes cap section data representing a cap section that delimits the tissue volume anteriorly, lenticule section data representing a lenticule section that delimits the tissue volume posteriorly, lateral section data representing a lateral section that delimits the tissue volume radially at least in sections with respect to the main optical axis and that extends in sections at least as far as the cap section and at least as far as the lenticule section, and access section data representing at least one access section. The present invention further relates to a computer program product, a data signal, and a computer-readable non-volatile storage medium.

[0002] Human vision defects have long been corrected with supplementary lenses in the form of glasses or contact lenses. However, for more than 20 years, various approaches have been developed to correct these defects by modifying the cornea. The modification alters the curvature of the cornea, thus correcting the refractive power of the eye. This can be achieved, for example, by removing tissue from the cornea. This alters the refractive power of the cornea in such a way that—taking into account the overall imaging properties of the eye—the refractive error is reduced or even completely eliminated.

[0003] The applicant has developed a particularly gentle procedure for corneal modification called SMILE. In this procedure, a femtosecond laser is used to create flat incisions in the cornea that enclose a lenticule-shaped piece of corneal tissue. This lenticule is removed from the cornea through an access incision (also called an incision) also created with the femtosecond laser. This creates a change in the curvature of the anterior surface (also called the front surface) of the cornea (i.e., at the interface between the cornea and air). This change in curvature changes the refractive power of the cornea, thus correcting a refractive error.

[0004] To create the flat incisions in the cornea, pulsed laser radiation for treating the eye is focused within the tissue—that is, below the surface of the tissue—in such a way that optical breakthroughs are created. This effect, called photodisruption, is observed particularly with picosecond and femtosecond lasers, but also with nanosecond lasers (shorter pulses result in lower fluences [in mW / cm 2] in focus is necessary to generate optical breakthroughs). Optical breakthroughs are also achieved in media that are transparent to the laser radiation. Typical (central) wavelengths of picosecond and femtosecond lasers can be around 800 nm, around 1030-1060 nm, around 1300 nm, around 1500 nm, or around 1900-2000 nm. Furthermore, the corresponding wavelength ranges at half, third, quarter, etc. wavelengths are accessible through frequency multiplication through nonlinear effects. For example, with an Nd:YAG laser at 1064 nm, pulsed laser light with a central wavelength of 532 nm can be achieved by frequency doubling, 355 nm by frequency tripling, and 266 nm by frequency quadrupling. All subject matter of the invention is explicitly not directed to an excimer laser, i.e.that the laser therapy device explicitly does not include an excimer laser with laser wavelengths in the UV range and that the control data generated by the planning unit or the planning procedure are not applicable to an excimer laser.

[0005] In the tissue, various processes initiated by the laser radiation take place sequentially. Multiphoton absorption generates a plasma, which expands through the absorption of further photons in an avalanche effect. If the power density of the radiation exceeds a threshold, an optical breakthrough occurs, which creates a plasma bubble in the material. This plasma bubble grows after the optical breakthrough occurs due to expanding gases. If the optical breakthrough is not maintained, the gas generated in the plasma bubble is absorbed by the surrounding material, and the bubble disappears again. However, this process takes much longer than the formation of the bubble itself. For the sake of simplicity, the processes mentioned are summarized here under the term optical breakthrough, i.e.This term encompasses not only the actual optical breakthrough, but also the resulting effects in the material. If a large number of optical breakthroughs are created next to each other in the fabric, a flat cut (cut surface) can be created.

[0006] An incision that defines a lenticule in the cornea of ​​an eye typically has a cap incision, a lenticule incision, a side incision, and an access incision. The cap incision (also called a cap cut or flap cut) defines the lenticule - the volume of tissue to be isolated from the cornea for removal - anteriorly, towards the front of the cornea. The lenticule incision (also called a lenticule cut) defines the lenticule posteriorly, towards the retina of the eye. The lenticule incision can, for example, be created in a partial incision with a decreasing path radius (i.e. from the outside in) or with an increasing path radius (i.e. from the inside out). The side incision (also called a side cut or lenticule side cut) defines the lenticule laterally opposite a main optical axis of the eye and extends to both the cap incision and the lenticule incision.The access incision extends to both the cap incision and the anterior aspect of the cornea. The isolated volume of tissue within the cornea can be removed through the access incision.

[0007] Furthermore, the access incision serves as an access point for separating the lenticule, which is usually still connected to the surrounding corneal tissue by material bridges, from the areas of the cornea anterior to the lenticule and from the remaining area of ​​corneal tissue posterior to the lenticule. This can be done, for example, using a spatula-shaped tool inserted through the access incision, which can be used to remove the material bridges.

[0008] One of the biggest challenges in correcting lenticule removal during a procedure called small incision lenticule extraction (SMILE) is correctly identifying the two planes that define the lenticule's boundary to the surface of the eye and the retina, respectively—the lenticule incision and the cap incision. Being able to distinguish between the two planes is critical to ensure proper separation. The surgeon identifies the lenticule's marginal incision through a common incision and successively severs the tissue bridges remaining after laser treatment, first through the cap incision and then through the lenticule incision.

[0009] Successful access to both planes is crucial and not trivial. The risk of separating the lenticule incision first is high. If this is noticed during the procedure, subsequent separation of the cap incision is possible, but significantly more difficult. However, if this is not noticed, there is a risk of causing significant tissue damage by mechanically separating a third plane (not cut by the laser) below the lenticule incision.

[0010] To date, successful identification and separation of the two planes has largely been achieved solely through the skill, experience, and training of the surgeon. Only haptic and visual feedback and the resistance of the tissue during the procedure serve as a guide.

[0011] The object of the present invention is therefore to provide a method and a device for generating control data for correcting the refraction of an eye, which reduce the risk of incorrect identification and possibly incorrect separation of the cap cut and the lenticule cut, so that the risk of possible complications is reduced.

[0012] According to the invention, the object is achieved by the features of the independent claims. Preferred developments and refinements are the subject of the dependent claims.

[0013] The method comprises receiving data representing a need for refraction correction, calculating a corneal tissue volume to be removed, the calculation being based on the need for refraction correction, and calculating cutting surface data representing a cutting surface delimiting the tissue volume, the cutting surface data comprising cap cutting data representing a cap cutting that delimits the tissue volume anteriorly, lenticule cutting data representing a lenticule cutting that delimits the tissue volume posteriorly, lateral cutting data representing a lateral cutting that delimits the tissue volume at least in sections radially with respect to the main optical axis and that extends in sections at least as far as the cap cutting and at least as far as the lenticule cutting, and access cutting data representing at least one access cutting.

[0014] The planning method according to the invention for generating control data is carried out in particular before and independently of an eye surgery to be performed and is therefore not a surgical or therapeutic procedure. During this planning phase, no treatment or therapy of a patient is yet performed. The control data represents where and / or in what order and / or with what parameters a laser pulse is to be applied in the eye (more precisely: within the tissue of the eye) of a patient in order to achieve a correction of the patient's refraction through corneal modification.

[0015] The access cutting data, which are part of the cutting surface data calculated by the data processing device of the planning unit according to the invention, further represent: - a first access incision extending from a front of the cornea to the cap incision over a predetermined first azimuth angle range, and - a second access incision extending from the anterior surface of the cornea to the lenticule incision over a predetermined second azimuth angle range.

[0016] The calculated cutting surface data further comprise side surface segment cutting data which represent at least one side surface segment and, in this at least one side surface segment, at least one cutting parameter modification to be used, wherein the at least one side surface segment extends in the first azimuth angle range and in the second azimuth angle range at least from the lenticule cut to at least the cap cut, so that the cutting surface data represent at least one cutting surface which completely delimits the tissue volume, and wherein the device for data processing is further designed to generate control data representing at least the cutting surface.

[0017] This can make accidental penetration from the first access incision into the lenticule incision or from the second access incision into the cap incision more difficult or even impossible.

[0018] Thus, a region of the edge of the tissue volume, i.e., the lenticule, can be defined by the first and second azimuth angle ranges, with the corresponding region, i.e., the lateral surface segment, extending at least from the lenticule cut to at least the cap cut. This region is processed with different processing parameters compared to the other cut surfaces of the lenticule.

[0019] The invention also relates to the aforementioned ophthalmological laser therapy device, comprising - a design of a planning unit described previously or subsequently, - a control unit connected to the planning unit via at least one input and / or output interface for receiving the control data, - a laser device for providing therapeutic radiation, - a focusing device for focusing the therapeutic radiation in a focus for severing the cornea, and - a scanning device for shifting the focus of the therapeutic radiation in the cornea of ​​the eye to create the cutting surface.

[0020] The control unit is designed to control the laser device and / or the focusing device and / or the scanning device in order to shift the focus of the therapeutic radiation in the cornea of ​​the eye, ie within the tissue of the eye, in order to produce the cutting surface in the cornea in accordance with the control data.

[0021] In the following description, the optional improvements to the control data are related to the patient's eye or cornea. This is to be understood as the theoretical location of the planned but not yet performed incisions in the patient's eye. If characteristics of the control data and / or incision data are described, this also includes the fact that the corresponding design of the planning unit, using the data processing device, is configured to calculate, generate, and provide precisely these control data with the aforementioned characteristics.

[0022] The need for refractive correction can be determined through previous measurements of the patient's eye and represented by correction data. This correction data is used to calculate the volume of corneal tissue to be removed using the planning procedure. Various objective and subjective measurements are known to determine the need for refractive correction, and these can be combined. Measurements of the structure of the eye, for example, via an OCT measurement, as well as measurements of intraocular pressure and the topography of the eye, can also be incorporated into the refractive correction requirement.

[0023] The tissue volume is preferably located within the tissue of the eye and is delimited or defined by cross-sectional areas. These cross-sectional areas are represented by the calculated cross-sectional area data.

[0024] As previously described, the tissue volume (i.e., the lenticule) is composed of different cutting surfaces. Each of these cutting surfaces is represented by corresponding cutting surface data, for example, the cap cutting data, which represents a cap cutting that delimits the tissue volume anteriorly; the lenticule cutting data, which represents a lenticule cutting that delimits the tissue volume posteriorly; the lateral cutting data, which represents a lateral cutting that delimits the tissue volume radially at least in sections with respect to the main optical axis and that extends in sections at least as far as the cap cutting and at least as far as the lenticule cutting; and the access cutting data, which represents at least one access cutting.

[0025] According to the invention, the access incision data represent at least a first access incision extending from the anterior surface of the cornea to the cap incision and a second access incision extending from the anterior surface of the cornea to the lenticule incision. Thus, the first access incision is provided for access to the cap incision, and the second access incision is provided for access to the lenticule incision. This allows for better identification of the different planes and minimizes complications due to confusion.

[0026] After the individual cutting data have been calculated in the planning process, the control data are generated, which represent at least the cutting surface.

[0027] The control or planning data may further include laser parameter data and / or device data and / or other patient data.

[0028] The planning unit and the planning method can be improved in that the first access incision extends with respect to the main optical axis around the main optical axis over a predetermined first azimuth angle range from the front of the cornea to the cap incision; and the second access incision extends with respect to the main optical axis around the main optical axis over a predetermined second azimuth angle range from the front of the cornea to the lenticule incision.

[0029] Both access incisions, preferably spatially separated, can thus form circular arc segments. This facilitates access to the cap incision via the first access incision or to the lenticule incision via the second access incision. Furthermore, the circular arc segment design allows the surgeon to reach all areas of the cap incision or lenticule incision when severing the material bridges.

[0030] The first and second azimuth angle ranges can be arranged differently from each other or overlapping; both azimuth angle ranges can be identical.

[0031] In such a configuration, the access points for the cap incision are located at different depths of the cornea. Preferably, in this configuration, the (access) openings provided on the surface of the cornea are spatially spaced from each other at different radial distances from the main optical axis. This has the advantage that the access incisions are only located within an identical azimuth angle range, and as little corneal tissue as possible needs to be cut. This allows as few nerves in the cornea as possible to be cut and consequently damaged, without reducing the ability to distinguish between the cap incision and the lenticule incision. Distinguishability is still ensured due to the two different and separate access incisions.

[0032] Furthermore, the two azimuth angle ranges may overlap or be adjacent to each other or be azimuthally spaced from each other.

[0033] In embodiments in which the azimuth angle ranges do not overlap, the planned openings on the surface of the cornea can be the same distance from the main optical axis, since the different angular orientations ensure differentiation. In a special case, the first access incision and the second access incision can be diametrically opposed, purely by way of example and not by way of limitation. However, both access incisions are preferably located on one side, for example, in one quadrant of a coordinate system related to the eye, in order to allow the surgeon access to both planes without the need to change position. In this case, the planning can also take into account whether the surgeon is right-handed or left-handed, purely by way of example.Likewise, the position of the azimuth angle ranges can be adapted to surgical conditions, for example whether the surgeon sits at the head of the patient or to the side of the patient during the operation.

[0034] Preferably, the first and / or second access cut have at least two regions in the radial direction from the main optical axis which have different pitch angles to the main optical axis.

[0035] The different pitch angles can facilitate both access to the corresponding level of the cap cut or lenticule cut, as well as the introduction of the tool for cutting the material bridges from the surface of the eye.

[0036] In this case, a first region of the at least two regions can extend from the front of the cornea to a second of the at least two regions, a last of the at least two regions can extend to the cap incision for the first access incision, and a last of the at least two regions can extend to the lenticule incision for the second access incision. In particular, only two regions can be provided, so that the last region corresponds to the second region. However, any number of additional regions can also be provided between the first and last regions.

[0037] In particular, the last region may include a larger inclination angle to the main optical axis than the first region.

[0038] It is particularly advantageous if the last region of the first access incision essentially borders continuously on the cap incision or merges continuously into it and / or if the last region of the second access incision essentially borders continuously on the lenticule incision or merges continuously into it. “Essentially continuous” is to be understood as meaning that there is only a slight angular deviation between the last region of the respective access incision and the associated cap incision or lenticule incision. This angular deviation is preferably less than 30°, more preferably less than 20°, more preferably less than 10°, and even more preferably the angle between the last region of the respective access incision and the associated cap incision or lenticule incision is approximately 0°. In the latter case, the incisions merge continuously into one another.

[0039] It is advantageous if the last section of the second access incision is at a greater distance from the corneal surface than the last section of the first access incision. This ensures that the first access incision provides access to the cap incision and the second access incision provides access to the lenticule incision.

[0040] In a further embodiment of the planning method, the first access incision and / or the second access incision may be L-shaped when viewed counter to the azimuthal direction. This allows for the smooth insertion of the tool from the surface of the cornea along the first area and a substantially smooth transition from the last area of ​​the respective access incision to the cap incision or lenticule incision.

[0041] Depending on the position of the azimuth angle ranges relative to each other, the side surface segment intersection data may represent a single side surface segment if the first azimuth angle range and the second azimuth angle range are identical, overlap, or adjacent to each other.

[0042] Alternatively, if the first and second azimuth angle ranges are azimuthally spaced from each other, the side surface segment intersection data represents two separate side surface segments.

[0043] This one or these two lateral surface segments are further assigned a cutting parameter modification by the control or planning data. This means that when the control or planning data is executed with an ophthalmic laser therapy device, the processing parameters in the lateral surface segment(s) are modified. In particular, the modification is carried out in such a way that each lateral surface segment is structurally weakened less by the processing than the remaining lateral surface of the lateral cut, the cap cut, or the lenticule cut.

[0044] Advantageously, the cutting parameter modification may include at least one modification of the cutting parameters from the list of modifications, comprising a) Increasing the spatial distance between two adjacent points of a planned laser processing; b) reducing a laser pulse energy; or c) exposure to a laser emission.

[0045] This means that in case a), a scan width, i.e., the distance between two optical apertures in the tissue in the processing plane, is increased. The scan width can be varied, for example, by varying the scanning speed of the scanning device and / or by varying the pulse repetition rate of the laser device (e.g., by varying the parameters of a pulse picker). This also increases the size of the remaining tissue bridges, and the corneal tissue can reduce the risk of accidental penetration from the first access incision into the lenticule incision or from the second access incision into the cap incision in the area of ​​the lateral surface segment due to the greater resistance of the material.In other words, the haptic resistance of the corneal tissue in the area of ​​the lateral surface segment(s) that the surgeon perceives is increased by the parameter modification compared to the resistance of the tissue in the access incision or in the cap incision (starting from the first access incision) or in the lenticule incision (starting from the second access incision). This makes it easier for the surgeon to separate the correct plane with the surgical tool than to penetrate the incorrect plane. The perceptible resistance from the first access incision to the lenticule incision is thus greater than from the first access incision to the cap incision. Likewise, the perceptible resistance from the second access incision to the cap incision is greater than from the second access incision to the lenticule incision.

[0046] In the case of modification b) above, it is advantageous if the laser pulse energy is reduced only to the extent that it still reaches a threshold value for achieving photodisruption. However, with reduced laser pulse energy, the effective radius of the developing gas bubble can be reduced. The effect on the stability of the machined area of ​​the side surface segment(s) is similar to that of modification a).

[0047] Ultimately, laser emission in the region of the lateral surface segment(s) can also be completely eliminated. This means that no laser pulse is irradiated into the lateral surface segment, and the corneal tissue remains untreated. This solution is conceivable, for example, if the distance between the lenticule cut and the cap cut is small enough to still allow the corneal tissue to be separated in the lateral surface segment. This distance is preferably less than 100 µm, more preferably less than 50 µm, more preferably less than 30 µm, and even more preferably less than 20 µm.

[0048] The planning method can be improved by making a modification of at least one processing parameter dependent on the polar angle. This means that the modification of one or more cutting parameters varies from the lenticule cut to the cap cut (and consequently also from the cap cut to the lenticule cut), i.e., the cutting parameters are changed to varying degrees. In particular, the cutting parameters can be constant across the entire lateral surface segment at a constant polar angle. The data used or calculated by the planning unit, the ophthalmic laser therapy device, and the planning method can be in spherical coordinates purely by way of example and not by way of limitation, wherein, in particular, the main optical axis of the eye can be defined as the polar axis.

[0049] Given this dependence on the polar angle, it is particularly advantageous if the planning method generates control data or the data processing device of the planning unit is designed to generate control data according to which the modification of the cutting parameters is reduced, at least in sections, in the first azimuth angle range from the cap cut to the lenticule cut and in the second azimuth angle range from the lenticule cut to the cap cut. In other words, in the first azimuth angle range, the modification of the cutting parameters is maximum at the transition between the cap cut and the side surface segment (i.e., the reduction in tissue stability is minimal) and decreases towards the lenticule cut (i.e., the reduction in tissue stability is maximum). Accordingly, in the second azimuth angle range, the modification of the cutting parameters is maximum at the transition between the lenticule cut and the side surface segment and decreases towards the cap cut.A maximum modification of the cutting parameters corresponds to a minimal weakening of the processed tissue, i.e. a minimal reduction in the stability of the tissue.

[0050] By applying the greatest possible modification of the cutting parameters at an access adjacent to the access tunnel to the cap incision or lenticule incision, the probability of accidental penetration of a surgical tool (preferably spatula-shaped, for example, to be suitable for cutting the material bridges) from the first access incision into the lenticule incision or from the second access incision into the cap incision is reduced due to the lesser reduction in the stability of these areas.

[0051] Furthermore, it is advantageous if a modification according to a) and / or according to b) has a minimum within a polar angle range covered by the at least one side surface segment for overlapping areas of the first and second azimuth angle range.

[0052] This is the case for identical or overlapping first and second azimuth angle ranges. In the case of identical azimuth angle ranges, the resulting lateral surface segment extends over exactly the common azimuth angle range. From the lenticule cut to the cap cut, the resulting lateral surface segment further extends over a polar angle range, the size of which can vary depending on the refractive correction required and consequently also depending on the shape and / or size of the tissue volume to be removed. Across this polar angle range, a modification of the cutting parameters can be maximum at the end of the lateral surface segment adjacent to the lenticule cut and at the end adjacent to the cap cut, and decrease to a minimum towards the opposite end of the lateral surface segment.

[0053] This progression toward the minimum modification of the cutting parameters means that the structural integrity of the corneal tissue is least compromised at the transition from the cap cut to the lateral surface segment and at the transition from the lenticule cut to the lateral surface segment (for example, due to enlarged remaining tissue bridges due to a greater distance between the laser pulses impinging on the tissue), and the tissue in the lateral surface segment between the lenticule cut and the cap cut is most compromised and thus easier to transect. In the case of identical azimuth angle ranges, this can be the case across the entire azimuth angle range.

[0054] If the two azimuth angle ranges merely overlap each other, the modification described above can only be provided in an overlapping area of ​​the azimuth angle ranges, depending on the polar angle.

[0055] In particular, an embodiment of the planning method or the planning unit can provide that, according to the generated control data, the cutting parameters correspond at a minimum to the cutting parameters in the cap cut and / or in the lenticule cut.

[0056] In such a design, only the areas of the side surface element(s) adjacent to an access tunnel are machined with modified machining parameters. These areas are thus less weakened and thus offer greater resistance to penetration into the wrong plane.

[0057] These cutting parameters can also be used in the side cut and / or the approach cut. Ideally, all cuts except the side surface element(s) are cut with the same machining or cutting parameters.

[0058] The computer program product according to the invention comprises instructions which, when loaded into a data processing device, cause the device to carry out an embodiment of the planning method described above.

[0059] A data signal according to the invention transmits the computer program product described above.

[0060] A computer-readable non-volatile storage medium according to the invention comprises the computer program product described above. Such a storage medium can be a magnetic storage medium, an optical storage medium, or a storage medium based on RAM, ROM, or EEPROM. The storage medium can be a CD, a DVD, a floppy disk, a magnetic tape, a hard disk (HDD or SSD), or another storage medium.

[0061] The planning unit can be provided as a stand-alone device or be part of an ophthalmic therapy device.

[0062] In particular, the planning unit can operate independently of an ophthalmic therapy device and can be implemented, for example, on a remote PC, a separate PC, or in a cloud as software, hardware, or a combination of software and hardware. The planning unit can be provided as Software-as-a-Service (SaaS).

[0063] A data processing device may be a PC, a microcontroller, an FPGA or a similarly designed device for calculating and generating the control data.

[0064] The invention further relates to a method for correcting the refraction of an eye by corneal modification, comprising carrying out an embodiment of the planning method described above; cutting (within the tissue) of the cornea of ​​the eye according to the provided control data; releasing the tissue volume along the cap cut through the first access cut; releasing the tissue volume along the lenticule cut through the second access cut; releasing the tissue volume along the lateral cut; and removing the tissue volume from the cornea of ​​the eye through the first or second access cut.

[0065] Compared to known solutions and, for example, compared to the regular generation of control data for a SMILE operation, both the lenticule cut, the edge cut and the cap cut are adapted to the position (azimuth angle) and width (azimuth angle range) of the planned access cuts.

[0066] For the lenticule cut and the cap cut, the second and first access cuts, respectively, are placed in segments on the circular cut surfaces. These access cuts act as access tunnels to the lenticule cut and the cap cut, respectively. For the edge cut, in one embodiment, only those areas that do not border an access cut, each of which represents an access tunnel, are actually cut, according to control data.

[0067] Depending on the planned positions of the first and second access incisions, either no incision is made at all in the adjacent areas of the side incision element(s), meaning the incision by laser pulses is completely suspended, or these areas are machined with modified processing parameters. For example, purely as an example and not as a limitation, larger spot spacing or lower laser pulse energy can be set to achieve weaker separability and minimize the risk of penetrating the other plane at this point (i.e., from the first access incision into the lenticule incision or from the second access incision into the cap incision).

[0068] In one embodiment of the ophthalmic laser therapy device, a planning unit, or a planning method, the function of providing a first access incision and a second access incision can be deactivated. For example, the advanced parameters in the planning software can be grayed out and the cap incision can be displayed as usual, circular and concentric to the lenticule.

[0069] According to the invention, the two access incisions can be freely positioned.

[0070] The aspects of the present invention will be explained in more detail below with reference to the accompanying drawings. The drawings show possible exemplary embodiments of the present invention purely by way of example, whereby the described features can be combined with one another or omitted as desired. Identical features or features with the same function are also identified by the same reference numerals. Repetitive descriptions of features are omitted, so that explanations of features described in previous drawings can also be applied to other drawings, unless differences are explicitly pointed out.

[0071] They show: Fig. 1 a schematic representation of the ophthalmic laser therapy device; Fig. 2 a schematic representation of the position of different sections of a tissue volume in the eye; Fig. 3 a schematic detailed representation of Fig. 2; Fig. 4 the representation of the Fig. 2 in top view; Fig. 5 another possible arrangement of the access incisions; Fig. 6 another possible arrangement of the access incisions; Fig. 7 shows another possible arrangement of the access incisions; Fig. 8 a schematic representation of the side section areas (for the case of the Fig. 5 shown access incisions); Fig. 9 a schematic representation of possible courses of modification of processing parameters (for the case of Fig. 5 shown access incisions); Fig. 10a schematic representation of further possible courses of modification of processing parameters (for the case of Fig. 2-4 shown access cuts); and Fig. 11 a schematic representation of an ophthalmic laser therapy device.

[0072] In the Fig. 1 schematically shows an ophthalmological laser therapy device 1 and a focusing device 3 of the ophthalmological therapy device 1. The ophthalmological laser therapy device 1 generates therapy radiation 5, which is generated by a laser device not shown (see Fig. 11). The therapeutic radiation 5 is focused by the focusing device 3 into a focus 7, where photodisruption 9 occurs. An eye 13 is schematically shown in a treatment area 11. The eye 13 has a cornea 15, which is shown here in a highly simplified manner. The cornea is bounded anteriorly by a surface 17 and posteriorly by a rear surface 19.

[0073] The treatment of the eye 13 by the laser device preferably takes place within the tissue of the cornea 15.

[0074] Furthermore, a tissue volume 21 to be removed from the cornea 15 is shown schematically, which can also be referred to as a lenticule 23. The indicated tissue volume 21 is located within the cornea and has not yet been removed from the cornea 15. The tissue volume 21 is present as a tissue volume 21 represented by planning data. The following explanations of the tissue volume 21 and the sections or cutting surfaces that form it are used merely to illustrate a schematic position on or in the eye. The indicated sections or the area bounding the indicated tissue volume 21 are represented by the control data before the actual treatment of the eye 13.

[0075] The tissue volume 21 is defined by several cut surfaces 25 (only one is shown here with a reference symbol). Furthermore, the eye 13 has a main optical axis 27.

[0076] In the Fig. 2 schematically shows the position of the cut surfaces 25 bordering the tissue volume 21 according to calculated control data. The tissue volume 21 is shown here from the side, as a reference and for comparison of the position with Fig. 1, the main optical axis 27 and the surface 17 can serve.

[0077] The tissue volume 21 is delimited anteriorly by a cap cut 29 and posteriorly by a lenticule cut 31 and is schematically represented by dotted hatching. Furthermore, the tissue volume 21 is delimited by a lateral cut 33, which is arranged at least partially radially around the tissue volume 21 with respect to the main optical axis 27, wherein the lateral cut 33 extends from the lenticule cut 31 to the cap cut 29.

[0078] Furthermore, a first access incision 35 is shown, which extends from a front side 37 of the cornea 39 to the cap incision 29.

[0079] In addition, a second access incision 41 is shown, which extends from the front surface 37 of the cornea 39 to the lenticule incision 31.

[0080] The first access cut 35 and the second access cut 41 are represented by the access cut data. In the Fig. 3 and Fig. 4 the access cuts are now explained in more detail.

[0081] The Fig. 2, detail 43 is enlarged in Fig. 3 shown.

[0082] It can be clearly seen that the first access cut 35 and the second access cut 41 have a first region 45 and a second or last region 47, which have different gradients, more precisely a first gradient 49 and a second gradient 51, respectively. In the case shown, the second region corresponds to the last region 47, whereas in other embodiments, a further region may be provided between the first region 45 and the last region 47.

[0083] The first access incision 35 and the second access incision 41 are accessible from outside the eye 13 at a first access point 53 and a second access point 55, respectively, on the front side 37 of the cornea 39. These access points 53, 55 are spaced apart from each other.

[0084] The Fig. Figure 4 shows a plan view of the eye 13, with the main optical axis 27 projecting vertically from the plane of the drawing. Fig. 4 it can also be seen that the access points 53, 55 are a circular segment-shaped first 57 and second access opening 59.

[0085] The first access opening 57 allows access to the cap cut 29 and the second access opening 59 allows access to the lenticule cut 31. The respective accesses to the cap cut 29 and the lenticule cut 31 are schematically represented by a first arrow 73 and a second arrow 75. A first 61 and a second access tunnel 63 created by the access cuts 35 and 41 are schematically shown in Fig. 4 is shown.

[0086] The first access tunnel 61 is created by the first access cut 35 and is characterized by an ascending hatching, whereas the second access tunnel 63 is created by the second access cut 41 and is characterized by a descending hatching. As can be seen from Fig. As can be seen in Figure 3, both access tunnels 61 and 63 are located one above the other in sections.

[0087] The access tunnels 61, 63 or the access openings 57 and 59 extend with respect to the main optical axis 27 over a predetermined first azimuth angle range 65 or a predetermined second azimuth angle range 67. In the Fig. 4, the first and second azimuth angle ranges 65, 67 are identical.

[0088] The last region 47 of the first access incision 35 essentially transitions continuously into the cap incision 29. The last region 47 of the second access incision 41 essentially transitions continuously into the lenticule incision 31. Both access incisions 35, 41 have an L-shape 70, opposite to an azimuthal direction 69.

[0089] In the Fig. Figure 5 shows a further embodiment of the first access incision 35 and its first access opening 57 and the associated first access tunnel 61. In this embodiment, the first access incision 35 is arranged adjacent to the second access incision 41 and the associated second access opening 59 and the correspondingly associated second access tunnel 63. The corresponding azimuth angle ranges 65 and 67 are thus different and adjacent to one another. Nevertheless, the first access incision 35 only provides access to the cap incision 29, and the second access incision 41 only provides access to the lenticule incision 31.

[0090] In the Fig. 6 and Fig. 7 shows further possible arrangements of the first access cut 35 and the second access cut 41 as well as the associated first 57 and second access tunnels 59 and azimuth angle ranges 65 and 67. The first 35 and the second access cut 41 can be spaced apart ( Fig. 6) or, for example, opposite each other ( Fig. 7) with respect to the main optical axis 27.

[0091] The Fig. Figure 8 shows a schematic view of a portion of the side cut 33 as seen from the main optical axis 27. Both the shape and size are not to scale. Also shown is the Fig. 5 shows the arrangement of the first 35 and the second access cut 41.

[0092] Shown is the side cut 33, represented by hatching with wavy lines. Adjacent to these are a first side surface segment 71 and a second side surface segment 73. Both the first and second side surface segments 71, 73 are rectangular and extend from the lenticule cut 31 to the cap cut 29, more precisely from a second abutment edge 31A, at which the lenticule cut 31 abuts the side cut 33, wherein the second abutment edge 31A is annular and is interrupted only by the first and second side surface segments 71, 73, to a first abutment edge 29A, at which the cap cut 29 abuts the side cut 33, wherein the first abutment edge 29A is also annular and is interrupted only by the first 71 and second side surface segments 73.

[0093] Each of the two side surface segments 71, 73 is spanned by a corresponding first azimuth angle range 65 for the first access section 35 or the second azimuth angle range 67 for the second access section 41, and by a polar angle range 75, which is identical for both access sections 35, 41. The side surface segments 71, 73 can be sections of a cylindrical surface or can also represent free-form surfaces, wherein the shape depends essentially on the required shape and size of the lenticule 23, which in turn are calculated from the refraction correction requirement R.

[0094] The cap cut 29, the lenticule cut 31, the side cut 33 and all side surface segments 71, 73 completely define the tissue volume 21.

[0095] A modification of cutting parameters ΔP takes place in each side surface segment 71, 73. This is stored in the planning data 90.

[0096] In the Fig. Figure 9 schematically illustrates different possible courses of the modification of cutting parameters. Considering the course from a second cutting edge 31A to a first cutting edge 29A, a possible course of the modification of cutting parameters ΔP for the second side surface segment 73, which is defined by the second azimuth angle range 67, is shown with a solid line.

[0097] For the first side surface segment 71, a corresponding progression of the modification of cutting parameters ΔP is shown with a dashed line. It can be seen that the modification of the cutting parameters ΔP is maximum at the corresponding access tunnel (i.e., the second access tunnel 63 for the second side surface segment 73 or the first access tunnel 61 for the first side surface segment 71).

[0098] If this is considered for the second access tunnel 63 of the second access incision 41, this means that a significant modification of the incision parameters ΔP occurs in the region of the first incision edge 31A. According to the planning data, the corneal tissue is thus processed in the vicinity of the first incision edge 31A, which, for example, occurs with an increased spatial distance between two adjacent points of a planned laser processing or with reduced laser pulse energy compared to the remaining incisions.

[0099] The corneal tissue near the first cutting edge 31A is thus less easy to cut through and thus remains more stable than, for example, the areas of the edge cut 33 marked with wavy lines. If a tool is thus introduced along the second access tunnel 63 towards the lenticule cut 31, there is non-perforated tissue or less strongly perforated corneal tissue at the first cutting edge 31A in the direction of the second cutting edge 29A than is the case in the direction of the lenticule cut 31. Inserting the tool into the lenticule cut 31 is therefore more likely than accidentally reaching the cap cut 29 via the second access tunnel 63. Inserting the tool into the cap cut 29 via the second access tunnel 63 is thus made more difficult or even completely avoided.

[0100] Accordingly, the corneal tissue in the first lateral surface segment 71 near the first cutting edge 29A is less perforated and less easily severed than at the second cutting edge 31A due to the modified processing parameters, and accidental penetration of the tool, which was introduced into the first access tunnel 61, into the lenticule cut 31 is made more difficult or prevented.

[0101] In the Fig. 10 are also two possible courses of the modification of cutting parameters ΔP for the Fig. 4, the case of overlapping azimuth angle ranges 65, 67 is shown. In this case, there is only one (common) lateral surface segment 71 for the first access incision 35 and the second access incision 41. In order to prevent or complicate accidental access from the first access incision 35 into the lenticule incision 31 or from the second access incision 41 into the cap incision 29, the change in the processing parameters ΔP is maximum both at the second cutting edge 31A and at the first cutting edge 29A and can have a minimum 75 or a plateau 77 between these cutting edges 29A, 31A, so that the tissue volume 31 is also planned to be separable from the eye in the region of the lateral surface segment 71.

[0102] In Fig. Figure 11 schematically illustrates an embodiment of an ophthalmic laser therapy device 1. During operation of the ophthalmic laser therapy device 1, a laser device 110 emits therapy light 5 in the form of a pulsed laser beam 115. The laser beam 115 is deflected laterally (in the x and y directions) by a scanning device 130 and axially (z direction) by another scanning device 135. In other embodiments, the laser beam 115 can first be adjusted in the z direction by the other scanning device 135 and subsequently deflected laterally in the x and y directions by the scanning device 130.

[0103] A focusing device 3 focuses the pulsed laser beam 115 in a focus 7 in the cornea 15, ie within the tissue of the eye 13. In Fig. 6 shows the focus 7 for two positions in the cornea 15 for different settings of the lateral scanning device 130 and the axial scanning device 135. A potentially advantageous fixation of the eye by means of a patient interface relative to the ophthalmic laser therapy device 1 is not shown.

[0104] During operation, the laser device 110, the scanning devices 130, 135, and the focusing device 3 are controlled fully automatically via signal data transmitted from a control unit 140 to the respective devices 110, 113, 130, 135. This is indicated by arrows pointing from the control unit 140 to the devices 110, 113, 130, and 135, respectively. The control unit 140 ensures suitably synchronous operation of the laser device 110, the three-dimensional scanning devices 130, 135, and, if applicable, the focusing device 3. The signal data can be transmitted via signal data lines 80 or wirelessly. The signal data required during operation is determined in the control unit 140 based on the control data 90. The control data 90 is received by the control unit 140 beforehand from the planning unit P as a control data set 92 via unspecified communication paths such as control lines 94 (in Fig.6 as a solid line between the planning unit P and the control unit 140). The control data 90 can also be transmitted using memory chips 96 (e.g., via USB or memory stick), magnetic storage devices 98 (e.g., floppy disks), wirelessly via radio (e.g., WLAN, UMTS, Bluetooth), or wired (e.g., USB, Firewire, RS232, CAN bus, Ethernet, etc.). As an alternative to direct communication, it is also possible to arrange the planning device P spatially separate from the control unit 140 and to provide a corresponding data transmission channel. The transmission preferably takes place before the operation of the ophthalmic laser therapy device 1, i.e., before control signals are transmitted to the laser device 110, the scanning devices 130, 135, and, if applicable, to the focusing device 3.

[0105] The control data set 92 is transmitted to the control unit 140 of the ophthalmic laser therapy device 100 via an input and / or output interface S2 of the planning device P.

[0106] The control data 90 represents, on the one hand, the various cuts, such as the cap cut 29, the lenticule cut 31, the edge cut 33, as well as the first access cut 35, the second access cut 41, and the lateral surface segment 71, or the first lateral surface segment 71 and the second lateral surface segment 73, as well as the modifications of the processing parameters ΔP to be applied in these lateral surface segments. Preferably, operation of the ophthalmic laser therapy device 1 is blocked until a valid control data set 92 is available at the control unit 140. A valid control data set 92 can be a control data set 92 that is, in principle, suitable for use with the control unit 140 of the ophthalmic laser therapy device 1. In addition, validity can also be linked to the passing of further tests.For this purpose, it can be checked, for example, whether additional information stored in the control data record 92 about the ophthalmic laser therapy device 100, e.g., a device serial number 90a, or about the patient, e.g., a patient identification number 90b, matches other information that was, for example, read out on the ophthalmic laser therapy device 1 or entered separately as soon as the patient is in the correct position for operation of the ophthalmic laser therapy device 1.

[0107] The planning device P generates the control data 90 or the control data set 92, which is provided to the control unit 140 of the ophthalmic laser therapy device 1 for carrying out the surgical procedure. In the embodiment shown here, the refraction correction requirement R is input via an input device (not shown) and provided to the planning unit P via a first interface S1. In other embodiments, the refraction correction requirement R can also be input via the input and / or output interface S2. The input device can be part of the ophthalmic laser therapy device 1 or can be configured independently.

[0108] The planning unit P comprises a calculation device C. This is connected to the first interface S1 and receives the refraction correction requirement R of the eye. In the calculation device C, control data 90 for correcting the refraction of the eye 13 by means of corneal modification are then calculated. The control data 90 are transmitted to the control unit 140 via the input and / or output interface S2. With the aid of the transmitted control data 90, the control unit 140 can generate signal data S1, S2, S3 and transmit them to the devices 110, 113, 130, 135 so that a cutting surface can be created in the cornea 15 (i.e., within the corneal tissue) of the eye 13. It should be noted again that the planning unit P can generate the control data 90 regardless of whether the eye 13 is connected to the ophthalmic laser therapy device 1 or not.

Claims

[1] Planning unit for generating control data for a surgical intervention within a tissue of the cornea of ​​an eye, which has a main optical axis, with an ophthalmological laser therapy device, wherein the ophthalmological laser therapy device comprises a laser device, a focusing device, a scanning device, and a control unit, wherein the planning unit comprises a device for data processing, which is designed: a. to receive correction data representing a need for refraction correction, b. to calculate the volume of corneal tissue to be removed, based on the refractive correction required, c. to calculate sectional area data representing a sectional area surrounding the tissue volume, wherein the sectional area data i. Cap cut data, lenticule cut data, side cut data, and access cut data, wherein the access cut data comprises at least ii. represent a first access cut extending from an anterior surface of the cornea to the cap cut over a predetermined first azimuth angle range and iii. represent a second access cut which extends from the front of the cornea to the lenticule cut over a predetermined second azimuth angle range, and wherein the cutting surface data further comprise lateral surface segment cutting data which represent at least one lateral surface segment and, in this at least one lateral surface segment, at least one cutting parameter modification to be used, wherein the at least one lateral surface segment extends in the first azimuth angle range and in the second azimuth angle range at least from the lenticule cut to at least the cap cut, so that the cutting surface data represent at least one cutting surface completely delimiting the tissue volume, and wherein the data processing device is further configured to generate control data representing at least the cutting surface. [2] Planning unit according to claim 1, wherein the data processing device is designed to calculate the access intersection data such that the side surface segment intersection data represent one side surface segment or two side surface segments spaced apart from one another. [3] Planning unit according to claim 1 or 2, wherein the device for data processing is designed to calculate the access cutting data in such a way that the cutting parameter modification comprises at least one modification of the cutting parameters from the list of modifications, comprising a. Increasing the spatial distance between two adjacent points of a planned laser processing operation; b. Reducing a laser pulse energy; or c. Exposure to a laser emission. [4] Planning unit according to claim 3, wherein in the calculation a modification is dependent on the polar angle. [5] Planning unit according to one of claims 1 to 4, wherein the device for data processing is designed to calculate the access cutting data in such a way that the modification of the cutting parameters in the first azimuth angle range from the cap cut to the lenticule cut and in the second azimuth angle range from the lenticule cut to the cap cut is reduced at least in sections. [6] Planning unit according to one of claims 1 to 5, wherein the device for data processing is designed to calculate the access intersection data in such a way that the modification according to a) and / or according to b) has a minimum within a polar angle range covered by the at least one side surface segment for overlapping areas of the first and second azimuth angle range. [7] Planning unit according to claim 6, wherein the data processing device is designed to calculate the access cutting data in such a way that the cutting parameters at a minimum substantially correspond to the cutting parameters in the cap cut and / or in the lenticule cut. [8] An ophthalmic laser therapy device for performing a surgical procedure within a tissue of the cornea of ​​an eye according to control data, comprising - a planning unit according to one of claims 1 to 7 for generating control data, - a control unit connected to the planning unit via at least one input and / or output interface for receiving the control data, - a laser device for providing therapeutic radiation, - a focusing device for focusing the therapeutic radiation in a focus for severing the cornea, and - a scanning device for shifting the focus of the therapeutic radiation in the cornea of ​​the eye, wherein the control unit is designed to control the laser device and / or the focusing device and / or the scanning device in order to shift the focus of the therapeutic radiation within the tissue of the cornea of ​​the eye in order to create the cutting surface in the cornea in accordance with the control data. [9] An ophthalmic laser therapy device according to claim 8, wherein the laser device comprises a pulsed picosecond laser or a pulsed femtosecond laser. [10] Planning method for generating control data for a surgical intervention within a tissue of the cornea of ​​an eye for correcting the refraction of the cornea of ​​the eye, which has a main optical axis, by corneal modification, comprising a) Receiving correction data representing a need for refraction correction, b) Calculating the volume of corneal tissue to be removed, based on the refractive correction required, c) Calculating sectional area data representing a sectional area surrounding the tissue volume, wherein the sectional area data ◯ Cap cut data, which represent a cap cut that limits the tissue volume anteriorly, ◯ Lenticule section data, which represent a lenticule section that delimits the tissue volume posteriorly, ◯ Lateral section data representing a lateral section that delimits the tissue volume radially with respect to the main optical axis at least in sections and that extends in sections at least to the cap section and at least to the lenticule section, and ◯ Access interface data representing at least one access interface, wherein the access interface data comprises at least ◯ represent a first access cut extending with respect to the main optical axis around the main optical axis over a predetermined first azimuth angle range from a front surface of the cornea to the cap cut and ◯ represent a second access cut extending with respect to the main optical axis around the main optical axis over a predetermined second azimuth angle range from the front of the cornea to the lenticule cut, wherein o the cutting surface data further comprise side surface segment cutting data, which represent at least one side surface segment and in this at least one side surface segment at least one cutting parameter modification to be used, wherein the at least one side surface segment extends in the first azimuth angle range and in the second azimuth angle range at least from the lenticule cut to at least the cap cut, so that the cutting surface data represent at least one cutting surface completely delimiting the tissue volume, and d) Generating control data representing at least the cutting surface. [11] The planning method according to claim 10, wherein the first and second azimuth angle ranges are adjacent to each other. [12] A planning method according to claim 10 or 11, wherein the side surface segment intersection data represents one side surface segment or two side surface segments spaced apart from each other. [13] Planning method according to one of claims 10 to 12, wherein the cutting parameter modification comprises at least one modification of the cutting parameters from the list of modifications, comprising a. Increasing the spatial distance between two adjacent points of a planned laser processing operation; b. Reducing a laser pulse energy; or c. Exposing to a laser emission, wherein a modification is preferably dependent on the polar angle. [14] Planning method according to claim 13, wherein the modification of the cutting parameters in the first azimuth angle range from the cap cut to the lenticule cut and in the second azimuth angle range from the lenticule cut to the cap cut is reduced at least in sections. [15] Planning method according to claim 13 or 14, wherein a modification according to a) and / or according to b) has a minimum within a polar angle range covered by the at least one side surface segment for overlapping areas of the first and second azimuth angle range. [16] Planning method according to claim 15, wherein the cutting parameters correspond at a minimum to the cutting parameters in the cap cut and / or in the lenticule cut. [17] A computer program product comprising instructions which, when loaded into a data processing device, cause the device to execute a planning method according to any one of claims 10 to 16. [18] A method for correcting the refraction of an eye by corneal modification within the tissue of the cornea, comprising - carrying out a planning method according to one of claims 10 to 16; - Cutting the cornea of ​​the eye according to the provided control data; - Release of the tissue volume along the cap incision through the first access incision; - Release of the tissue volume along the lenticule incision through the second access incision; - Release of the tissue volume along the lateral incision; and - removing the tissue volume from the cornea of ​​the eye through the first or second access incision.

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