Method for providing control data for ophthalmic laser of therapeutic device for hyperopia correction

Abstract

A method for providing control data for an ophthalmic laser (12) of a treatment device (10) for hyperopia correction of a cornea (16). The method comprises, as steps, determining (S10) corneal data of the cornea (16) from predetermined examination data; determining (S12) correction parameters of the hyperopia correction and corneal parameters of a virtual cornea assumed as a cornea (16) after treatment with the hyperopia correction from the determined corneal data; determining (S14) whether there is a preset limit criterion for at least one correction parameter of the hyperopia correction and / or at least one corneal parameter of the virtual cornea, wherein it is checked by the limit criterion whether at least one parameter limit in the hyperopia correction is exceeded; limiting (S16) at least one preset correction parameter of the hyperopia correction by means of a limit value if the limit criterion is present; and providing (S18) control data comprising a hyperopia correction with limited correction parameters.

Description

Technical Field

[0001] The invention relates to a method for providing control data for an ophthalmic laser of a treatment device for presbyopia correction of the cornea. Furthermore, the invention relates to a control device configured to perform the method, a treatment device having such a control device, a computer program comprising commands for causing the treatment device to perform the method, and a computer-readable medium having the computer program stored thereon. Background Art

[0002] Treatment devices and methods for controlling ophthalmic lasers to correct optical visual disorders or pathological and / or unnaturally altered areas of the cornea of ​​the eye are known in the prior art. Among them, the pulsed laser and the beam focusing device can, for example, be formed so that the laser pulses achieve photodisruption and / or ablation in a focus located within the organic tissue to remove tissue, in particular tissue lenticules, from the cornea.

[0003] When correcting hyperopia, the action possibilities of the laser parameters and / or corneal parameters may be limited, meaning that the originally planned or desired correction cannot be achieved or has adverse effects on the eye because it exceeds technical and / or physiological limitations. These limitations are often unknown to the user, so the planned treatment exceeds the possible or reasonable correction parameters. SUMMARY OF THE INVENTION

[0005] It is an object of the present invention to facilitate the planning of hyperopia correction.

[0006] This object is solved by the independent claims. Advantageous embodiments of the invention are disclosed in the dependent claims, the following description and the drawings.

[0007] The present invention is based on the idea of ​​automatically adjusting or limiting the correction parameter that exceeds the treatment optimization limit to improve the treatment. It can be specifically provided that, instead of limiting the correction parameter that exceeds the optimization limit, another correction parameter that depends on the correction parameter is limited.

[0008] A first aspect of the invention relates to a method for providing control data for an ophthalmic laser of a treatment device for corneal hyperopia correction, wherein the method comprises the following steps performed by a control device. The control device is understood to be an apparatus and / or an apparatus component, in particular a computer or a processor, which can automatically or semi-automatically perform the following steps.

[0009] It is achieved that corneal data of the cornea are determined based on predetermined examination data, correction parameters of a hyperopia correction and corneal parameters of a virtual cornea are determined based on the determined corneal data, the virtual corneal parameters being assumed to be the cornea after treatment with a hyperopia correction, and it is determined whether there is a preset limit criterion for at least one correction parameter of the hyperopia correction and / or at least one corneal parameter of the virtual cornea, wherein the limit criterion is used to check whether at least one parameter limit in the hyperopia correction is exceeded. In addition, it is achieved that if a limit criterion is present, at least one preset correction parameter of the hyperopia correction is limited by a limit value and control data are provided, the control data comprising the hyperopia correction with limited correction parameters.

[0010] In other words, corneal data can be determined based on predetermined examination data (e.g. topography and / or wavefront measurements) which specify the actual state of the cornea before treatment. Based on this corneal data (in which hyperopia may be present in particular), correction parameters to be used for treating hyperopia can then be determined. Furthermore, a virtual cornea can be determined, in which it is assumed that the cornea characterized by the corneal data has been treated by means of the correction parameters. This means that the virtual cornea represents a hypothetical post-operative cornea.

[0011] Subsequently, it can be determined whether there are preset limit criteria in the planned correction parameters and / or corneal parameters or in the virtual cornea generated therefrom. The limit criteria can include one or more conditions or rules, wherein the control device can check the corresponding correction parameters and / or corneal parameters to determine whether they are respectively met. Therein, a limit criterion can be present if at least one parameter limit in the correction parameters and / or a parameter limit in the virtual cornea is exceeded. For example, there may be limit criteria in the correction parameters if contradictory inputs are performed when planning the volume to be removed and / or too high a value is selected when planning a hyperopic correction. There may be limit criteria in the virtual cornea if, for example, it is determined that in the virtual cornea, the residual thickness is too low at a certain location and / or the treatment produces too high a curvature, which, for example, impairs the stability of the cornea after the treatment.

[0012] If there is a limiting criterion, at least one preset correction parameter, in particular a correction parameter that may deviate from the limiting criterion, may be limited by a preset limit value. This means that if the first correction parameter and / or the corneal parameter is above the parameter limit, the second correction parameter may be limited to a value or a value range that can be optimized for the treatment device. In addition to limiting the correction parameters, or for example if a parameter close to a parameter limit is determined, a warning may also be output. This means that a warning may be generated for the user to make him aware of the parameter limits, in particular before the limiting criterion occurs and / or if the preset correction parameters are limited. For example, a warning may be output via a user interface of the treatment device. The user can then decide whether to stop the treatment completely or whether to continue using the limited correction parameters, or whether to maintain the originally planned correction parameters that exceed the parameter limits and thus cancel the restrictions.

[0013] Finally, control data for controlling an ophthalmic laser may be provided, which control data may be generated based on finite correction parameters for hyperopia correction.

[0014] For example, the correction parameters may include the value of the diopter change or refractive change for hyperopia correction, the size and / or position of the treatment zone (particularly the optical zone), the laser energy and / or the pulse distance. The corneal parameters of the virtual cornea may include, for example, the residual thickness of the cornea after treatment, the curvature value achieved, the aberration value and / or the refractive value achieved.

[0015] By means of the present invention, it is advantageously possible to facilitate the user in planning the hyperopia correction, since the correction parameters can be adjusted or limited to preset limits in an automated manner. This also increases the safety of the treatment, since incorrect adjustments of the parameters can be reduced.

[0016] The invention also includes embodiments that produce additional advantages.

[0017] In an embodiment, a limiting criterion exists if the virtual cornea is thinner at the periphery than at the center. Here, the virtual cornea viewed radially refers to the center and the periphery, wherein the center can be located in the area of ​​the pupil center point and / or the corneal vertex and the periphery is radially spaced from the center. In particular in hyperopic correction, there is a risk that the periphery is too thin compared to the center, which can be avoided here. Therein, not the entire periphery has to be thinner when viewed in azimuth, but a limiting criterion may exist if, for example, a predetermined portion of the periphery (e.g. more than 10% of the periphery) is thinner than the center.

[0018] Specifically, if the virtual cornea is 1.2 times thinner at the edge than at the center, a warning is generated. This can be checked based on the radial position starting from the center, so that, for example, a limit criterion exists when there are the following pairs of values ​​that specify a diameter and a corresponding ratio of thickness (center / edge) at the corresponding diameter: (6mm; 1.15), (7mm; 1.175), 8mm; 1.2), (9mm; 1.225), and (10mm; 1.25).

[0019] In another embodiment, if the mean curvature of the virtual cornea exceeds 49 diopters, then there is a limit criterion. In other words, if the mean curvature of the virtual cornea (averaged across all meridians, as expected after treatment) is greater than 49 diopters, then there is a limit criterion. From a follow-up examination, this value is considered critical.

[0020] Specifically, if the average curvature of the virtual cornea exceeds 47 diopters, a warning will be generated. This means that before the preset correction parameters are limited by the limit value of 49 diopters, a warning will be generated when exceeding 47 diopters.

[0021] In another embodiment, there is a limiting criterion if the curvature of a meridian of the virtual cornea exceeds 50 diopters. This means that at least one correction parameter is limited if the curvature of a single meridian of the virtual cornea exceeds 50 diopters.

[0022] Specifically, if the curvature of the meridian of the virtual cornea exceeds 48 diopters, a warning is generated.

[0023] In another embodiment, if the determined spherical aberration of the virtual cornea is lower than -0.7 diopters, then there is a limiting criterion. In other words, if the spherical aberration is less than -0.7 diopters, for example -0.8 diopters, then there is a limiting criterion.

[0024] Specifically, if the determined spherical aberration of the virtual cornea is below -0.5 diopters, a warning is generated.

[0025] In another embodiment, if the average diopter change of the hyperopia correction exceeds 6 diopters, a warning is generated. In other words, if a diopter change of more than 6 diopters is to be performed as a correction parameter, a warning message may be provided.

[0026] In another embodiment, a warning is generated if the diopter change of the meridian of the virtual cornea exceeds 8 diopters.

[0027] In another embodiment, if a limiting criterion is present, the diameter of the treatment zone defined by the optical zone and the transition zone is limited to a value less than the blade diameter value as a correction parameter, wherein the blade diameter value is defined as the diameter of the planned foldable corneal blade minus the hinge height that the corneal blade has at the remaining joint with the cornea. In other words, when a limiting criterion is present, the diameter of the treatment zone may be limited to be less than the diameter of the foldable corneal blade, which is also minus the hinge height. Thus, for example, the following formula may be used:

[0028] OZ+TZ<plate diameter – hinge height,

[0029] Where OZ is the optical zone and TZ is the transition zone. In addition, a constant value between 0 and 0.7 mm, in particular 0.5 mm, can be subtracted from the plate diameter value to take into account the tolerance range.

[0030] In another embodiment, if there is a limiting criterion, the diameter of the treatment zone defined by the optical zone and the transition zone is limited to a value less than the corneal diameter value as a correction parameter, wherein the corneal diameter value is defined as the corneal diameter minus the double offset value of the pupil center to the corneal vertex. In other words, the value to which the treatment zone is limited can be the corneal diameter value, which can be defined by the following formula:

[0031] OZ+TZ<corneal diameter – 2*offset from pupil center to corneal vertex

[0032] A constant value can also be subtracted therefrom, which lies in the range of 0.75 mm to 1.25 mm, wherein this constant value ensures the distance to the corneal limbus.

[0033] In another embodiment, if a limiting criterion is present, the diameter of the optical zone is limited to a value above the 6 mm limit as a correction parameter. This means that the optical zone of the treatment area can be set to be greater than or equal to 6 mm.

[0034] In another embodiment, if there is a limiting criterion, the diameter of the treatment zone defined by the optical zone and the transition zone is limited to a value above the 7 mm limit as a correction parameter. In other words, if there is a limiting criterion, the treatment zone, i.e., the optical zone, can be limited together with the transition zone to be greater than or equal to 7 mm.

[0035] Another aspect relates to a method for controlling a therapeutic device. The method comprises the method steps of at least one embodiment of the method as previously described. In addition, the method for controlling a therapeutic device comprises the step of transmitting the provided control data to at least one ophthalmic laser of the therapeutic device and controlling the therapeutic device and / or the laser using the control data.

[0036] The control data may include a corresponding data set for positioning and / or focusing the individual laser pulses in the cornea. Additionally or alternatively, the control data may include a corresponding data set for adjusting at least one beam device for beam guidance and / or beam shaping and / or beam deflection and / or beam focusing of the laser beam of the corresponding laser.

[0037] The corresponding method may include at least one additional step, which is performed if and only if an application case or application situation occurs, which application case or application situation is not explicitly described here. For example, this step may include outputting an error message and / or outputting a request for input user feedback. Additionally or alternatively, it may be provided that a default setting and / or a predetermined initial state are adjusted.

[0038] Another aspect of the present invention relates to a control device, which is formed to perform the steps of at least one embodiment of the aforementioned method. In addition, the control device may include a computing unit, such as a processor, for electronic data processing. The computing unit may include at least one microcontroller and / or at least one microprocessor. The computing unit may be configured as an integrated circuit and / or a microchip. In addition, the control device may include an (electronic) data memory or a storage unit. A program code may be stored on a data memory, by which the steps of the corresponding embodiment of the corresponding method are encoded. The program code may include control data for the corresponding laser. The program code may be executed by a computing unit, thereby causing the control device to perform the corresponding embodiment. The control device may be formed as a control chip or a control unit. The control device may, for example, be included in a computer or a computer cluster.

[0039] Another aspect of the invention relates to a treatment device having at least one eye surgery or ophthalmic laser and a control device, which is formed to perform the steps of at least one embodiment of the aforementioned method. The corresponding laser can be formed to at least partially separate a predetermined corneal volume from a predetermined interface of the human or animal eye by optical breakdown, in particular by photodisruption and / or by ablating corneal layers by means of (photo)ablation and / or achieving a laser-induced refractive index change in the cornea and / or the eye lens and / or increasing cross-linking of the cornea.

[0040] In another embodiment of the treatment device according to the invention, the laser can be suitable for emitting laser pulses with a wavelength range between 300nm and 1400nm, for example between 900nm and 1200nm, and a repetition frequency greater than 10 kilohertz (kHz), for example between 100kHz and 100 megahertz (MHz), with a corresponding pulse duration between 1fs and 1ns, for example between 10fs and 10ps. The use of such a laser in the method according to the invention also has the advantage that the irradiation of the cornea does not have to be carried out in a wavelength range below 300nm. This range is included in the term "deep ultraviolet" in laser technology. As a result, accidental damage to the cornea caused by these extremely short wavelength and high-energy beams is advantageously avoided. Photodisruptive and / or ablative lasers of the type used here usually input pulsed laser radiation with a pulse duration between 1fs and 1ns into the corneal tissue. As a result, the power density of the corresponding laser pulses required for optical breakdown can be narrowly limited spatially, so that high cutting accuracy can be achieved in the generation of the interface. In particular, the range between 700 nm and 780 nm may also be selected as the wavelength range.

[0041] In another embodiment of the therapeutic device according to the invention, the control device may include at least one storage device for at least temporarily storing at least one control data set, wherein one or more control data sets include control data for positioning and / or for focusing individual laser pulses in the cornea; and may include at least one beam device for beam guiding and / or beam shaping and / or beam deflection and / or beam focusing of the laser beam of the laser.

[0042] Another aspect of the invention relates to a computer program. The computer program includes, for example, commands forming a program code. The program code may include at least one control data set having corresponding control data for a corresponding laser. When the program code is executed by a computer or a computer cluster, the previously described method or at least one embodiment thereof is performed.

[0043] Another aspect of the present invention relates to a computer-readable medium (storage medium) on which the above-mentioned computer program and its commands are stored respectively. In order to execute the computer program, a computer or a computer cluster can access the computer-readable medium and read out its content. For example, the storage medium is formed as a data memory, in particular at least partially formed as a volatile or non-volatile data memory. The non-volatile data memory can be a flash memory and / or an SSD (solid state drive) and / or a hard disk. The volatile data memory can be a RAM (random access memory). For example, the command can exist as a source code of a programming language and / or as an assembler and / or as a binary code.

[0044] Further features and advantages of one of the aspects described herein may result from the embodiments of another aspect of the invention. Therefore, if the features of the embodiments of the invention are not explicitly described as mutually exclusive, they may exist in any combination with each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Below, additional features and advantages of the present invention are described in the form of advantageous implementation examples based on the accompanying drawings. The features or feature combinations of the implementation examples described below may exist in any combination in combination with each other and / or with the feature combinations of the implementation examples. This means that the features of the implementation examples may supplement and / or replace the features of the implementation examples, and vice versa. Therefore, configurations are also considered to be covered and disclosed by the present invention, which are not explicitly shown or explained in the drawings, but are produced and can be generated by separate feature combinations from the implementation examples and / or implementation examples. Therefore, configurations are also considered to be disclosed, which do not include all the features of the originally proposed claims or extend beyond or deviate from the feature combinations set forth in the relationship of the claims. For the implementation examples, it is shown:

[0046] Figure 1 is a schematic diagram of a therapeutic device according to an exemplary embodiment;

[0047] Figure 2 Schematic process diagram according to an exemplary embodiment.

[0048] In the figures, identical or functionally identical elements are provided with the same reference symbols. DETAILED DESCRIPTION OF THE INVENTION

[0050] Figure 1 A schematic diagram of a treatment device 10 with an ophthalmic laser 12 for removing tissue 14 from a human or animal cornea 16 by photodisruption and / or ablation is shown. For example, the tissue 14 may represent a lenticule or also a volume 14, which may be separated from the cornea 16 by the ophthalmic surgical laser 12 for the correction of visual disorders, in particular hyperopia. The control device 18 may provide a correction profile or geometry of the volume 14 to be removed, in particular in the form of control data, which include correction parameters, so that the laser 12 emits pulsed laser pulses into the cornea 16 of the eye in a pattern predefined by the control data for the removal of the volume 14. Alternatively, the control device 18 may be a control device 18 external to the treatment device 10.

[0051] also, Figure 1 It is shown that a laser beam 20 generated by a laser 12 can be deflected toward the cornea 16 by a beam deflection device 22 (eg, a rotary scanner) to remove the volume 14. The beam deflection device 22 can also be controlled by a control device 18 to remove the volume 14.

[0052] In particular, the laser 12 shown may be a photodisruptive and / or photoablative laser formed to emit laser pulses having a wavelength in the range of between 300 nanometers and 1400 nanometers, for example between 700 nanometers and 1200 nanometers, with a corresponding pulse duration between 1 femtosecond and 1 nanosecond, for example between 10 femtoseconds and 10 picoseconds, and a repetition frequency of the laser pulses greater than 10 kilohertz, for example between 100 kilohertz and 100 megahertz. In addition, the control device 18 optionally comprises a storage device (not shown) for at least temporarily storing at least one control data set, wherein one or more control data sets comprise control data for positioning in the cornea and / or for focusing the individual laser pulses.

[0053] If a volume 14 is removed from the cornea 16 within the hyperopic correction range, some limitations in the correction parameters of the removed volume 14 need to be taken into account. In particular, if certain correction parameters of the cornea or corneal parameters expected postoperatively exceed the limiting values ​​in the treatment plan, other correction parameters must be adjusted to compensate in order not to compromise the treatment success rate. This means that there may be correlations between the individual correction parameters that must be taken into account but are not apparent in the treatment plan. In order to provide for these limitations in hyperopic correction, a correction parameter may be performed. Figure 2 The method shown in .

[0054] Figure 2 A schematic diagram of a method for providing control data to an ophthalmic laser 12 of a treatment device 10 for presbyopia correction of a cornea 16 is shown. The method can be performed by the control device 18 of the treatment device 10 or an external control device 18, for example.

[0055] In step S10, corneal data of the cornea 16 may be determined from predetermined examination data. Here, the corneal data represents the actual state of the cornea which may have farsightedness.

[0056] In step S12, a correction of hyperopia can be planned based on the determined corneal data, wherein correction parameters, in particular refractive changes, can be determined. In addition, in step S12, it can be estimated what the cornea 16 will look like after treatment using the correction parameters, wherein a virtual cornea with corresponding corneal parameters can be determined.

[0057] In step S14, it can then be determined whether at least one correction parameter of the planned hyperopia correction and / or at least one corneal parameter of the virtual cornea after the hyperopia correction is above a limit value or parameter limit, wherein it can be checked whether at least one limiting criterion exists for the correction parameter and / or the corneal parameter.

[0058] Regarding the corneal parameters of the expected virtual cornea, for example, it can be checked whether the thickness of the cornea at the periphery is thinner than the thickness at the center in the virtual cornea. Here, for example, if the periphery is 1.15 times thinner than the center, 1.175 times at 3.5 mm, 1.2 times at 4 mm, 1.225 times at 4.5 mm, and 1.25 times at 5 mm, it can be checked by observing radially from the center with a radius of 3 mm. In addition, it can be checked whether the average curvature of the virtual cornea exceeds 49 diopters, wherein if the average curvature exceeds these 49 diopters, there may be a restriction criterion. In addition, if the curvature of a single meridian of the virtual cornea exceeds 50 diopters, there may be a restriction criterion. If the spherical aberration of the virtual cornea is lower than -0.7 diopters, for example, it has -0.8 diopters, there may also be a restriction criterion.

[0059] In step S16, at least one preset correction parameter for the hyperopia correction may be limited by a limit value, wherein the correction parameter may differ from the correction parameter above the parameter limit.

[0060] Specifically, if there are limiting criteria, the diameter of the planned treatment zone defined by the optical zone and the transition zone can be limited to the correction parameter so that the limit value is above 7 mm. Alternatively or additionally, if there are limiting criteria, it can be specified that the optical zone is limited to above 6 mm.

[0061] Alternatively or additionally, the treatment zone can be limited to a corneal diameter value as a correction parameter defined by the corneal diameter minus twice the offset value of the pupil center to the corneal vertex, or the treatment zone can be limited to a value below the blade diameter value defined by the planned foldable corneal blade diameter minus the hinge height that the corneal blade has at the remaining joint with the cornea.

[0062] In addition to the limitations of the correction parameters, a warning message can be output when the parameter limit is approached in order to make the user aware of the limitation. The user can thus decide whether to modify the correction parameters, to stop the treatment plan or to further use the correction parameters above the parameter limit. In particular, a warning message can be output if the mean curvature of the virtual cornea exceeds 47 diopters, if the curvature of a single meridian of the virtual cornea exceeds 48 diopters, the spherical aberration of the virtual cornea is lower than -0.5 diopters, the mean refractive power change of the hyperopia correction exceeds 6 diopters and / or the refractive power change of a single meridian of the virtual cornea exceeds 8 diopters.

[0063] In contrast, if no limiting criteria exist, hyperopia correction can be performed using the initially determined correction parameters.

[0064] However, if there are limiting criteria and one of the mentioned correction parameters has been limited, the control device 18 can provide a hyperopic correction with limited correction parameters in step S18, wherein control data are generated, which can control the laser 12 and / or the beam deflection device 22 to perform the hyperopic correction. This means that the treatment device 10 can be controlled by the control data.

[0065] Overall, these examples demonstrate how the present invention can take into account parameter limitations of hyperopia correction.

Claims

1. A method for providing control data for an ophthalmic laser (12) of a treatment device (10) for the correction of presbyopia of a cornea (16), wherein the method comprises the following steps performed by a control device (18): - determining (S10) corneal data of the cornea (16) according to predetermined examination data; - determining (S12) correction parameters of the hyperopia correction and corneal parameters of a virtual cornea, which is assumed to be the cornea (16) after treatment with the hyperopia correction, based on the determined corneal data; - determining (S14) whether there is a preset limit criterion for at least one correction parameter of the hyperopia correction and / or at least one corneal parameter of the virtual cornea, wherein the limit criterion is used to check whether at least one parameter limit in the hyperopia correction is exceeded; - limiting (S16) at least one preset correction parameter of the hyperopia correction by a limit value if the limiting criterion exists; and - providing (S18) said control data, said control data comprising a hyperopia correction with finite correction parameters.

2. The method according to claim 1, wherein: The limiting criterion exists if the virtual cornea is thinner at the periphery than at the center.

3. A method according to any one of the preceding claims, wherein: If the virtual cornea is 1.2 times thinner at the periphery than at the center, a warning is generated.

4. A method according to any one of the preceding claims, wherein: The limiting criterion exists if the mean curvature of the virtual cornea exceeds 49 diopters.

5. A method according to any one of the preceding claims, wherein: If the average curvature of the virtual cornea exceeds 47 diopters, a warning is generated.

6. A method according to any one of the preceding claims, wherein: The limiting criterion exists if the curvature of the meridian of the virtual cornea exceeds 50 diopters.

7. A method according to any one of the preceding claims, wherein: If the curvature of the meridian of the virtual cornea exceeds 48 diopters, a warning is generated.

8. A method according to any one of the preceding claims, wherein: The limiting criterion exists if the determined spherical aberration of the virtual cornea is lower than -0.7 diopters.

9. A method according to any one of the preceding claims, wherein: If the determined spherical aberration of the virtual cornea is below -0.5 diopters, a warning is generated.

10. The method according to any one of the preceding claims, wherein: If the mean diopter change of the hyperopia correction exceeds 6 diopters, a warning is generated.

11. A method according to any one of the preceding claims, wherein: If the diopter variation of the meridian of the virtual cornea exceeds 8 diopters, a warning is generated.

12. A method according to any one of the preceding claims, wherein: If the limiting criterion exists, the diameter of the treatment zone defined by the optical zone and the transition zone is limited to a value less than the blade diameter value as the correction parameter, wherein the blade diameter value is defined as the diameter of the planned foldable corneal blade minus the hinge height of the corneal blade at the remaining joint with the cornea (16).

13. A method according to any one of the preceding claims, wherein: If the limiting criterion exists, the diameter of the treatment zone defined by the optical zone and the transition zone is limited to a value smaller than the corneal diameter value as the correction parameter, wherein the corneal diameter value is defined as the diameter of the cornea (16) minus the double offset value from the pupil center to the corneal vertex.

14. A method according to any one of the preceding claims, wherein: If the limiting criterion is present, the diameter of the optical zone is limited to a value above the limit value of 6 mm as the correction parameter.

15. A method according to any one of the preceding claims, wherein: If the limiting criterion is present, the diameter of the treatment zone defined by the optical zone and the transition zone is limited to a value above the limit value of 7 mm as a correction parameter.

16. Control device (18) configured to carry out a respective method according to any of the preceding claims.

17. A therapeutic device (10) comprising: at least one ophthalmic surgical laser (12) for separating a corneal body (14) from a predefined interface of a human or animal eye by optical breakdown, in particular by photodisruption and / or photoablation, and at least one control device (18) according to claim 16.

18. Computer program comprising instructions causing a therapeutic device (10) according to claim 17 to perform a method according to any one of claims 1 to 15.

19. Computer readable medium having stored thereon a computer program according to claim 18.

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