Method for providing control data for an ophthalmic ablation laser, control device, treatment device, computer program and computer-readable medium

Abstract

The invention relates to a method for providing control data for an ophthalmic surgical ablation laser (12) of a treatment device (10).The procedure comprises the following steps: determining an epithelial layer map of a cornea (16) from predetermined examination data; determining an anterior stromal wavefront map and an anterior corneal wavefront map from the predetermined examination data; determining a stromal ablation map based on the anterior stromal wavefront map; calculating an epithelial-stromal ablation map by adding the epithelial layer map to the stromal ablation map; determining a corneal ablation map based on the anterior corneal wavefront map; determining a final ablation map taking into account a difference between the epithelial-stromal ablation map and the corneal ablation map; and providing the control data for the ophthalmic ablation laser (12), which includes the final ablation map.

Description

The invention relates to a method for providing control data for an ophthalmic ablation laser of a treatment device. The invention further relates to a control unit configured to perform the method, a treatment device with at least one ophthalmic ablation laser and such a control unit, a computer program comprising commands that cause the treatment device to execute the method, and a computer-readable medium on which the computer program is stored. Treatment devices and methods for controlling ophthalmic lasers to correct refractive errors and / or pathologically or abnormally altered areas of the cornea are known in the prior art. For example, pulsed lasers and a beam deflection device can be configured such that laser pulses cause an optical breakthrough in corneal tissue, in particular an ablation, to remove the corneal tissue. One treatment option using an ablation laser is transepithelial photorefractive keratectomy (trans-PRK), in which an epithelial layer of the cornea is removed with the ablation laser. The intended refractive change is then achieved in the underlying corneal stroma by ablating stromal tissue. The planned refractive change occurs in the stroma because these changes are permanent, whereas the epithelial layer regenerates and therefore does not contribute to a change in corneal curvature. From DE 10 2023 119 297 A1, a method for providing control data for an ophthalmic laser of a treatment device is known. A control unit determines corneal parameters of an anterior surface of the cornea from predetermined examination data; determines an epithelial map of an epithelial layer of the cornea from the predetermined examination data, whereby the thickness of the epithelial layer is provided in the epithelial map; calculates a stromal wavefront map as a function of the determined corneal parameters of the anterior surface of the cornea and the determined epithelial map; determines correction data for correcting a refractive error based on the stromal wavefront map; and provides the control data that contains the correction data determined on the basis of the stromal wavefront map. From DE 10 2023 108 625 A1, a further method for providing control data for an ophthalmic laser of a treatment device for the correction of a cornea is known.The procedure comprises the following steps: determining topographical data of the preoperative cornea from predetermined examination data; calculating wavefront aberration data of the preoperative cornea using the topographical data, whereby the passage of light rays through the cornea, which exhibits the topographical data, is determined using a beam transmission model; determining an aberration-neutral correction profile by preserving higher-order aberrations of the preoperative cornea for a postoperative cornea, whereby a predetermined refractive correction is adjusted depending on the determined wavefront aberration data to determine the aberration-neutral correction profile; and providing the control data for corneal correction for the ophthalmic laser, which includes the aberration-neutral correction profile. From DE 10 2023 106 466 A1, a further method for providing control data for an ophthalmic laser of a treatment device is known. The method comprises the following steps: determining an initial correction value for correcting a refractive error of the cornea from predetermined examination data; determining epithelial layer parameters from the predetermined examination data and providing an epithelial layer regeneration model that describes the regeneration of an epithelial layer with the determined epithelial layer parameters; determining an adapted correction value depending on the initial correction value and the epithelial layer regeneration model; and providing the control data for the ophthalmic laser, which includes the adapted correction value. Especially in corneas with an irregular epithelial layer, the proportion of the epithelial layer in the correction has so far been insufficiently taken into account. Therefore, the object of the invention is to determine control data for an ophthalmic ablation laser that better take into account the contribution of an epithelial layer to the correction. This problem is solved by the independent patent claims. Advantageous embodiments of the invention are disclosed in the dependent patent claims, the following description, and the figures. One aspect of the invention relates to a method for providing control data for an ophthalmic ablation laser of a treatment device, wherein the method comprises the following steps performed by a control unit. A control unit is understood to be a device or device component, in particular a computer or processor of the treatment device, that can perform the following steps. The procedure involves determining an epithelial layer map of the cornea from predetermined examination data, determining an anterior stromal wavefront map and an anterior corneal wavefront map from the predetermined examination data, determining a stromal ablation map based on the anterior stromal wavefront map, calculating an epithelial-stromal ablation map by adding the epithelial layer map to the stromal ablation map, determining a corneal ablation map based on the anterior corneal wavefront map, determining a final ablation map taking into account a difference between the epithelial-stromal ablation map and the corneal ablation map, and providing the control data for the ophthalmic ablation laser, which includes the final ablation map, whereby the anterior stromal wavefront map and thus the stromal ablation map are determined indirectly.wherein the anterior stromal wavefront map is measured through an anterior corneal interface and wherein the epithelial-stromal ablation map is linearly combined with the corneal ablation map to obtain the final ablation map and to account for a phase shift caused by the anterior corneal interface. In other words, the control unit can be provided with examination data from which at least one epithelial layer and one stroma of the cornea can be determined. Specifically, an epithelial layer map and wavefront maps can be generated from this data. Firstly, an anterior corneal wavefront map can be determined, which indicates the phase shift of a light wave generated by the corneal surface. Secondly, an anterior stromal wavefront map can be determined, which indicates the phase shift generated by the stromal interface.In particular, the cornea can be composed of several layers from the outside in, i.e., along an incoming light ray, each layer potentially separated by interfaces. In simplified terms, the cornea has the anterior corneal interface, or corneal surface, which is also the anterior interface of the epithelial layer that follows within the cornea. The epithelial layer can regenerate after treatment, which is why it is removed during the procedure to allow for the planned corrections to be made to the underlying layer, the stroma. The stroma thus begins with the anterior stromal interface, which marks the end of the epithelial layer. Between the epithelial layer and the stroma lies Bowman's membrane, which can also be considered an anterior stromal interface.Beyond the stroma are further layers and membranes, which are not necessary for further explanation. The cornea finally ends with the posterior corneal interface. The epithelial layer map can specify the thickness and curvature of the epithelial layer, and can be provided in vertical sections. Furthermore, the epithelial layer map can also be fitted to Zernike polynomials, in particular Zernike polynomials up to the 8th order, to represent them consistently with respect to the wavefronts. A stromal ablation map can be determined from the anterior stromal wavefront map, meaning that the ablation volume can be determined to compensate for phase shifts provided by the wavefront map. Similarly, a corneal ablation map can be determined from the anterior corneal wavefront map, compensating for phase shifts that may arise from the corneal surface. The epithelial layer map can then be added to the stromal ablation map to also account for the epithelial tissue in transepithelial photorefractive keratectomy. That is, the amount of epithelial layer to be ablated by the ablation laser, plus the ablation map for the tissue to be ablated in the stroma, forms the epithelial-stromal ablation map. However, to account for the phase shift caused by the anterior corneal surface, the epithelial-stromal ablation map can be linearly combined with the previously determined corneal ablation map to obtain a final ablation map. For example, the corneal ablation map can be subtracted from the epithelial-stromal ablation map to determine the final ablation map. The final ablation map can then be planned for removal with the ophthalmic ablation laser by generating control data that includes this final ablation map. This control data can include positions for laser pulse irradiation and the number of laser pulses at each position to remove the final ablation map from the cornea.The control data may additionally or alternatively include a data set for setting at least one beam deflection device for beam guidance and / or beam shaping and / or beam deflection and / or beam focusing of a laser beam from the ablation laser. The treatment device or the ophthalmic ablation laser can then be controlled using this data to correct refractive errors. The ablation laser can, for example, be designed as an excimer laser, in which case it removes corneal tissue by ablation or vaporization. The cornea can thus be ablated layer by layer from a surface. The changes to the stroma remain constant, and the epithelial layer can regenerate after treatment. The invention offers the advantage that different parts of the cornea responsible for phase shifts can be taken into account. In particular, the anterior stromal wavefront map, and thus the stromal ablation map, can only be determined indirectly, as it is always measured through the corneal surface. Any resulting error can be taken into account using this method, leading to better treatment results and fewer aberrations. The invention also includes embodiments that offer additional advantages. One embodiment provides that the epithelial layer map is determined from a predetermined optical coherence tomography (OCT) scan or a predetermined ultra-high-frequency (UHF) ultrasound scan. Optical coherence tomography can identify the cornea, in particular the different corneal layers, thereby providing information on the thickness and structure of the individual layers. This can be achieved by irradiating the cornea with light waves. Ultra-high-frequency (UHF) ultrasound can also identify the individual layers of the cornea, in particular the epithelial layer and the stroma, whereby, in UHF ultrasound, sound waves are used instead of light waves, particularly in a frequency range of 20 MHz to 100 MHz. Another embodiment provides that, to determine the anterior stromal wavefront map, an anterior stromal interface is determined from a predetermined optical coherence tomography or ultra-high-frequency sonography scan. The determined anterior stromal interface is then used to generate the anterior stromal wavefront map by means of a ray tracing method or an analytical calculation based on Fermat's principle. In other words, the anterior stromal interface can also be determined using optical coherence tomography or ultra-high-frequency sonography. From the determined stromal interface, a wavefront generated by this process can then be calculated by simulating this anterior stromal wavefront using ray tracing or by computation based on Fermat's principle. Another embodiment provides that, to determine the anterior corneal wavefront map, an anterior corneal interface is determined from a predetermined topography or tomography measurement, wherein the determined anterior corneal interface is then used to calculate the anterior corneal wavefront map using a ray tracing method or an analytical calculation based on Fermat's principle. In other words, to determine the anterior corneal wavefront map, the anterior corneal interface can first be determined. Since this represents the corneal surface, it can be determined directly via a topography measurement, such as videokeratography or Pentacam, or from a tomography measurement, such as optical coherence tomography or ultra-high frequency sonography.Once the anterior corneal boundary has been determined, the anterior corneal wavefront map can be calculated from this by a ray tracing simulation or analytically according to Fermat's principle. Another embodiment provides that the following steps are performed to determine the stromal ablation map from the anterior stromal wavefront map: inverting the anterior stromal wavefront map by reversing its sign, shifting the inverted anterior stromal wavefront map in the depth direction of the stroma such that the inverted anterior stromal wavefront map lies within the boundaries of the stroma at every position, and scaling the inverted and shifted anterior stromal wavefront map by dividing it by n-1, where n is a refractive index of the cornea. In other words, the anterior stromal wavefront map can first be inverted by multiplying it by -1 to determine the corneal volume to be removed to compensate for the phase shift caused by the anterior interface.The corneal volume to be removed can then be aligned within the stroma by shifting it in the depth direction until all of it lies within the stroma. This means that no portion should extend beyond the anterior stromal interface, as tissue can only be removed, not added. Preferably, a maximum of the inverted anterior stromal wavefront map should coincide with the anterior stromal interface during the shift to minimize the amount of corneal volume removed from the stroma. Finally, the inverted and shifted anterior stromal wavefront map can be scaled to obtain the stromal ablation map, with scaling performed by dividing by n-1. Here, n is the refractive index of the cornea, which is typically assumed to be 1.376. Another embodiment provides that the following steps are performed to determine the corneal ablation map based on the anterior corneal wavefront map: inverting the anterior corneal wavefront map by reversing its sign, shifting the inverted anterior corneal wavefront map in the depth direction of the cornea such that the inverted anterior corneal wavefront map lies within corneal boundaries at every position, and scaling the inverted and shifted anterior corneal wavefront map by dividing it by n-1, where n is a refractive index of the cornea. In other words, the anterior corneal wavefront map can first be inverted by multiplying by -1 to determine the corneal volume to be removed to compensate for the phase shifts provided by the wavefront map.This volume can then be shifted deeper into the cornea, eliminating the need to "add" corneal tissue at any point. Here, too, it is preferable to ensure that a maximum of the inverted anterior corneal wavefront map coincides with an anterior corneal interface to conserve tissue. Finally, the shifted anterior corneal wavefront map can be scaled by dividing it by n-1 to generate the corneal ablation map. Here, n is the refractive index of the cornea, which can be as high as 1.376. Another embodiment provides that a linear combination of the epithelial-stromal ablation map and the corneal ablation map is calculated to determine the final ablation map. In other words, a difference between the epithelial-stromal ablation map and the corneal ablation map can be taken into account by linearly combining them. The linear combination can include the difference between the epithelial-stromal ablation map and the corneal ablation map. For example, a weighted averaging of both ablation maps can also be performed, where the weighting can specify the proportion to which each of the two ablation maps should be considered, in particular a value from 0% to 100%. Instead of averaging, a spatially resolved combination can also be performed, in particular also with weighting. Another embodiment provides that, to determine the epithelial stromal ablation map and the corneal ablation map, an epithelial layer regeneration component is added using an epithelial layer regeneration model that models epithelial layer regrowth. In other words, the epithelial layer regeneration model can account for how the epithelial layer regenerates after removal. For example, a regeneration rate, epithelial layer loss, and epithelial layer displacement can be modeled, for instance, using filter functions. In particular, it can be assumed that the epithelial layer has a different shape after treatment than before treatment, which can be taken into account by adding the epithelial layer regeneration component. The procedure may include at least one additional step that is executed precisely when a use case or application situation occurs that is not explicitly described here. This step may, for example, include the output of an error message and / or a prompt for user feedback. Additionally or alternatively, it may include setting a default value and / or a predetermined initial state. Another aspect of the invention relates to a control device configured to perform the steps of at least one embodiment of the previously described method. For this purpose, the control device may include a computing unit for electronic data processing, such as a processor. The computing unit may comprise at least one microcontroller and / or at least one microprocessor. The computing unit may be implemented as an integrated circuit and / or a microchip. Furthermore, the control device may include an (electronic) data storage device or a storage unit. Program code, which encodes the steps of the respective embodiment of the respective method, may be stored on the data storage device. The program code may include the control data for the respective laser.The program code can be executed by the processing unit, which then causes the control unit to execute the respective configuration. The control unit can be designed as a control chip or control device. The control unit can, for example, be part of a computer or computer network. A further aspect of the invention relates to a treatment device comprising at least one ophthalmic or surgical ablation laser and a control unit configured to perform the steps of at least one embodiment of the method described above. The ablation laser can be configured to remove a predefined ablation volume of a human or animal eye by means of optical breakthrough, in particular to remove corneal layers by means of (photo)ablation. In an advantageous further development of the treatment device, the ablation laser can be configured to emit laser pulses in a wavelength range between 150 nm and 250 nm, preferably between 175 nm and 215 nm, with a pulse duration between 1 fs and 100 ns, preferably between 10 ps and 10 ns, and a repetition frequency greater than 100 hertz (Hz), preferably between 400 Hz and 10 kilohertz (MHz). Such an ablation laser, which can be configured in particular as an excimer laser, is especially well suited for the ablation of corneal tissue. The use of lasers in a wavelength range below 300 nm, also known as "deep ultraviolet," can ablate corneal tissue particularly efficiently due to these very short-wavelength and high-energy beams. Photoablative lasers of the type used here typically introduce pulsed laser radiation with a pulse duration between 1 fs and 100 ns into the corneal tissue.The wavelength range can also be selected, in particular, between 175 nm and 215 nm. In a further advantageous embodiment of the treatment device, the control unit can have at least one storage device for at least temporary storage of at least one control data set, wherein the control data set(s) comprise control data for positioning and / or focusing individual laser pulses in the cornea; and can have at least one beam device for beam guidance and / or beam shaping and / or beam deflection and / or beam focusing of a laser beam of the laser. Another aspect of the invention relates to a computer program. The computer program comprises instructions that, for example, constitute program code. The program code can include at least one control data set with the respective control data for the respective laser. When the program code is executed by a computer or a computer network, it is caused to execute the method described above, or at least one embodiment thereof. Another aspect of the invention relates to a computer-readable medium (storage medium) on which the aforementioned computer program or its instructions are stored. To execute the computer program, a computer or a computer network can access the computer-readable medium and read its contents. The storage medium is, for example, designed as a data storage device, in particular at least partially as a volatile or non-volatile data storage device. A non-volatile data storage device can be flash memory and / or an SSD (solid-state drive) and / or a hard drive. A volatile data storage device can be RAM (random access memory). The instructions can be, for example, in the form of source code of a programming language and / or as assembly language and / or as binary code. Further features and advantages of one of the described aspects of the invention may arise from further developments of another aspect of the invention. The features of the embodiments of the invention can therefore exist in any combination with one another, unless they have been explicitly described as mutually exclusive. Additional features and advantages of the invention are described below with reference to the figure(s) in the form of advantageous embodiments. The features or combinations of features of the embodiments described below can be combined with each other and / or with the features of the embodiments. That is, the features of the embodiments can complement and / or replace the features of the embodiments, and vice versa. Therefore, embodiments that are not explicitly shown or explained in the figures, but which can be derived and generated from separate combinations of features in the embodiments and / or embodiments, are also to be considered as encompassed and disclosed by the invention.Thus, embodiments that do not exhibit all the features of an originally formulated claim, or that go beyond or deviate from the combinations of features set out in the cross-references of the claims, are also to be considered disclosed. Regarding exemplary embodiments: Fig. 1 shows a schematically represented treatment device with an ophthalmic ablation laser according to an exemplary embodiment; Fig. 2 shows a process diagram for a method according to an exemplary embodiment. In the figures, identical or functionally equivalent elements are provided with the same reference symbols. Figure 1 shows a schematic representation of a treatment device 10 with an ophthalmic ablation laser 12 for the removal of an ablation volume 14 or tissue from a human or animal cornea 16 by ablation. The ablation volume 14 can be created, for example, by removing corneal layers from the cornea 16 using the ophthalmic ablation laser 12, for example, to correct refractive errors. A correction profile or a geometry to be removed from the ablation volume 14 can be provided by a control unit 18, in particular in the form of control data, so that the ablation laser 12 emits pulsed laser pulses into the cornea 16 of the eye in a pattern predefined by the control data to create the ablation volume 14. Alternatively, the control unit 18 can be an external control unit 18 with respect to the treatment device 10. Furthermore, Fig. 1 shows that the laser beam 20 generated by the ablation laser 12 can be deflected towards the cornea 16 by means of a beam deflection device 22, such as a rotary scanner or controllable mirror, in order to create the ablation volume 14. The beam deflection device 22 can also be controlled by the control unit 18. The laser 12 shown is preferably a photoablative laser, in particular an excimer laser, configured to emit laser pulses in a wavelength range between 150 nanometers and 250 nanometers with a pulse duration between 1 femtosecond and 100 nanoseconds and a repetition frequency between 100 hertz and 10 kilohertz. The control device 18 optionally also includes a storage device (not shown) for at least temporarily storing at least one control data set, wherein the control data set(s) comprise control data for positioning and / or focusing individual laser pulses into the cornea. Furthermore, the control data may include a pulse sequence in which a temporal sequence of the respective laser pulses and / or a number of laser pulses at a position is defined. Figure 1 also shows a schematic cross-section through the cornea 16, which, from the outside in (depth direction), can comprise the following structures. The cornea 16 has an anterior corneal interface 24, the curvature of which provides a first refractive component. The anterior corneal interface 24 can also be referred to as the anterior epithelial interface, since the epithelial layer 26 follows below it. This layer is to be ablated during photorefractive keratectomy corrections using the ablation laser 12, as it regenerates and grows back after treatment. Subsequently, Bowman's membrane 28, or the anterior interface 28 of the stroma 30, follows, separating the epithelial layer 26 from the subsequent stroma 30. The epithelial layer 26 and the stroma 30 may have slightly different refractive indices, in particular approximately 1.4 for the epithelial layer and 1.38 for the stroma.Therefore, the curvature of the anterior interface 28 of the stroma 30 can result in a second refractive component that should be considered during treatment. Since the stroma 30, unlike the epithelial layer 26, does not regenerate, corrections or changes in refractive power should be planned within the stroma 30. However, in order to take into account the refractive power contributions of the anterior corneal interface 24 and the anterior stromal interface 28 in treatment planning to determine the ablation volume 14, the procedure shown in Fig. 2 can be carried out. Figure 2 shows a schematic process diagram for providing control data for the ophthalmic ablation laser 12 of the treatment device 10. The process can be carried out by the control unit 18 of the treatment device 10 or by an external control unit that functions as a planning unit. In step S10, an epithelial layer map of the cornea 16 can be determined from predetermined examination data. For example, optical coherence tomography or ultra-high frequency ultrasound can be applied to the cornea 16 to determine the epithelial layer 26. In step S12, an anterior stromal wavefront map and an anterior corneal wavefront map can be determined from the predetermined examination data. The anterior corneal wavefront map can be obtained by measuring the topology or tomography of the anterior corneal interface 24, by converting the anterior corneal interface into a wavefront using ray tracing or an analytical calculation according to Fermat's principle. Similarly, the anterior stromal interface 28 can be calculated as an anterior stromal wavefront map, whereby the anterior stromal interface can be determined from a tomography scan, in particular optical coherence tomography or ultra-high frequency sonography. An optical zone (OZ) can also be defined in which the treatment is to take place, for example, an optical zone with a diameter of 7 mm. Subsequently, ablation maps can be determined from the respective wavefront maps, whereby the procedure is independent of the order of determination. The determination of the stromal ablation map is described below, although the corneal ablation map could also be determined first, or both simultaneously. In this example, in step S14, the stromal ablation map is first determined from the anterior stromal wavefront map. For this purpose, the anterior stromal wavefront map is first inverted by means of a sign reversal, and the inverted anterior stromal wavefront map is then shifted in the depth direction into the stroma 30, specifically such that a maximum of the inverted wavefront map coincides with the anterior stromal interface 28.Finally, the inverted and shifted anterior stromal wavefront map can be scaled by dividing by n-1, where n is the refractive index of the cornea 16. In step S16, the epithelial layer map can then be added to the determined stromal ablation map to obtain an epithelial-stromal ablation map. This means that the ablation component resulting from the anterior stromal interface 28 is calculated, taking into account the removal of the epithelial layer 26. However, when measuring the anterior stromal interface 28, there is also an indirect effect from the anterior corneal interface 24, which is transferred to the epithelial-stromal ablation map due to error propagation, since the anterior stromal interface 28 is only measured indirectly. Therefore, the contribution of the anterior corneal interface 24 must still be considered. This can be determined in step S18 by determining a corneal ablation map based on the anterior corneal wavefront map. To determine the stromal ablation map, the anterior corneal wavefront map can be inverted by sign reversal. The inverted anterior corneal wavefront map can be shifted in depth into the cornea 16 such that the inverted anterior corneal wavefront map lies at every position within the boundaries of the cornea 16, in particular a maximum coinciding with the anterior corneal interface 24. The inverted and shifted anterior corneal wavefront map can be scaled by dividing by n-1, where n is the refractive index of the cornea 16. Subsequently, in step S20, a final ablation map can be determined taking into account a difference between the epithelial-stromal ablation map and the corneal ablation map, in particular by means of a difference between the epithelial-stromal ablation map and the corneal ablation map. The final ablation map can define the ablation volume 14 to be removed. Finally, in one step, control data S22 for the ophthalmic ablation laser 12 can be generated, comprising the final ablation map. Using this control data, the treatment device 10 or the ophthalmic ablation laser 12 can then be controlled to remove the ablation volume 14.

Claims

A method for providing control data for an ophthalmic ablation laser (12) of a treatment device (10), the method comprising the following steps performed by a control device (18): - Determining an epithelial layer map of a cornea (16) from predetermined examination data; - Determining an anterior stromal wavefront map and an anterior corneal wavefront map from the predetermined examination data; - Determining a stromal ablation map based on the anterior stromal wavefront map; - Calculating an epithelial-stromal ablation map by adding the epithelial layer map to the stromal ablation map; - Determining a corneal ablation map based on the anterior corneal wavefront map; - Determining a final ablation map taking into account any difference between the epithelial-stromal ablation map and the corneal ablation map;- Providing the control data for the ophthalmic ablation laser (12), comprising the final ablation map;- wherein the anterior stromal wavefront map and thus the stromal ablation map are determined indirectly, wherein the anterior stromal wavefront map is measured through an anterior corneal interface (24); and- wherein the epithelial-stromal ablation map is linearly combined with the corneal ablation map to obtain the final ablation map, taking into account a phase shift caused by the anterior corneal interface (24).; Method according to claim 1, wherein the epithelial layer map is determined from a predetermined optical coherence tomography or a predetermined ultra-high frequency sonography. Method according to one of the preceding claims, wherein to determine the anterior stromal wavefront map an anterior interface (28) of the stroma (30) is determined from a predetermined optical coherence tomography or a predetermined ultra-high frequency sonography, wherein the determined anterior interface (28) of the stroma (30) is determined to the anterior stromal wavefront map by means of a ray tracing method or an analytical calculation according to Fermat's principle. Method according to one of the preceding claims, wherein to determine the anterior corneal wavefront map the anterior interface (24) of the cornea (16) is determined from a predetermined topography measurement or tomography measurement, wherein the determined anterior interface (24) of the cornea (16) is determined to the anterior corneal wavefront map by means of a ray tracing method or an analytical calculation according to Fermat's principle. A method according to any of the preceding claims, wherein the following steps are performed to determine the stromal ablation map based on the anterior stromal wavefront map: - Inverting the anterior stromal wavefront map by means of a sign reversal; - Shifting the inverted anterior stromal wavefront map in the depth direction of the stroma such that the inverted anterior stromal wavefront map lies within limits of the stroma (30) at every position; - Scaling the inverted and shifted anterior stromal wavefront map by means of a division by n-1, where n is a refractive index of the cornea. A method according to any of the preceding claims, wherein the following steps are performed to determine the corneal ablation map from the anterior corneal wavefront map: - Inverting the anterior corneal wavefront map by means of a sign reversal; - Shifting the inverted anterior corneal wavefront map in the depth direction of the cornea (16) such that the inverted anterior corneal wavefront map lies within limits of the cornea (16) at every position; - Scaling the inverted and shifted anterior corneal wavefront map by means of a division by n-1, where n is a refractive index of the cornea. Method according to one of the preceding claims, wherein a linear combination of the epithelial-stromal ablation map and the corneal ablation map is calculated to determine the final ablation map. Method according to one of the preceding claims, wherein an epithelial layer regeneration component is added to the epithelial stromal ablation map and the corneal ablation map by means of an epithelial layer regeneration model that models regrowth of the epithelial layer. Control device (18) configured to perform a procedure according to any of the preceding claims. Treatment device (10) with at least one ophthalmic ablation laser (12) for the removal of a corneal volume (14) by means of optical breakthrough and at least one control device (18) according to claim 9 . Computer program comprising commands that cause the treatment device (10) according to claim 10 to perform a method according to any one of claims 1 to 8. Computer-readable medium on which a computer program according to claim 11 is stored.

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