Apparatus and method for refractive surgery, in particular keratoplasty

Abstract

The invention relates to a device and a method for refractive surgery, in particular keratoplasty. The object of the invention is to specify a device and a method for producing and implanting a lamella of tissue or material in order to correct the corneal geometry with the highest precision, in turn improved with respect to the prior art. The object of the correction is in particular to reconstruct the normal corneal geometry with an improved corneal optical function with respect to the prior art. This object is achieved by a planning device (2), a treatment system (1) and a planning method, which are designed to couple the device coordinate systems of the participating laser devices (3, 6, 7) and of the characterization device (4) by means of recordings, and to record the delivered measurement data for generating the lamella (24) to be implanted individually with respect to the device coordinate systems by means of a defined specific edge geometry of the blank (23) and the lamella (24) machined in itself, and further system and method aids.

Description

Technical Field

[0001] This invention relates to apparatus and methods for refractive surgery, particularly keratoconlasty, such as for seamless intrastromal anterior keratoconlasty (sIALK). Background Technology

[0002] To date, devices and methods for refractive surgery, particularly keratotomy, described, for example, in DE 10 2007 019 815 A1 and WO 2008 / 131888 A1, are based on the principle of always extracting tissue from the recipient eye during treatment. For this reason, the sIALK method has been described as requiring excision at all times, as this creates a deepening in the stromal bed (vacancy), which simplifies the correct placement of the implant or graft. Vacancy has inherent disadvantages, namely the surgical burden and tissue loss associated with its creation. However, the advantages generally outweigh the disadvantages, namely the simplified acquisition of biopsy material and the simplification of implant placement.

[0003] In a specific design scheme, in addition to the improvement in spectacle visual acuity (CDVA), uncorrected visual acuity (UDVA) is also improved. Therefore, spectacle correction is performed simultaneously. This concept has also been partially described in DE 10 2007 019815A1 or WO 2008 / 131888 A1.

[0004] In the manufacture of implants, particularly tissue implants, shaping can be performed in various ways. One possible approach involves imprinting the target geometry onto the implant blank using laser processing. This is of particular interest for refractive surgery, as the refractive laser systems commonly used there can be adapted to this method with minimal overhead. Therefore, patient-specific fitting of the implant can be performed by the clinic's medical user without needing to be done in a tissue bank or elsewhere. This approach offers logistical advantages and also reduces some risks to the patient.

[0005] However, simply transferring the processing methods of PRK or LASIK treatment to implant manufacturing cannot reliably achieve the required manufacturing precision. This is because, unlike the usual practice of using stromal corneal tissue during shaping to correct visual impairment, it is not uncommon to peel layers thicker than 100 μm during implant manufacturing. In the case of stromal corneal tissue typically used for visual impairment correction during shaping, approximately up to 13 μm of tissue is removed per refractive correction, and maximum peels exceeding 100 μm are rare. Achieving absolute precision in the micrometer range with such large peels is more difficult than achieving the relatively high precision requirements of PRK correction, especially since the properties of the implant material undergo greater fluctuations than in the case of stromal tissue during PRK or LASIK treatment.

[0006] In addition to shaping the implant within the tissue's correction zone, exceptionally high precision is required at the implant's edges. This tissue can be natural donor corneal tissue or artificial tissue with properties similar to natural corneal tissue. The existing vacancy in the periphery of the implant, known as the edge, typically needs to be precisely fitted into the tissue. (This requires a precision of at least 10 μm, but ideally 5 μm or less. Ideally, it can be fitted precisely to 1 μm.) One aspect of the challenge is that the surgeon should not damage the implant's edges during the procedure, such as when separating the tissue to be transplanted from the donor eye's surrounding tissue or when removing unwanted portions of material. The construction process naturally requires manual microsurgical work using surgical instruments. Summary of the Invention

[0007] The object of this invention is to describe an apparatus and method for manufacturing and implanting a thin film of tissue or material with the highest precision and an improvement over the prior art, in order to improve corneal geometry correction. The aim of the correction is, in particular, to reconstruct normal corneal geometry with improved corneal optical function compared to the prior art.

[0008] This invention comprises various measures or features, all of which are intended to improve the aforementioned apparatus and methods for refractive surgery, particularly keratoplasty, and ultimately to achieve the common goal of manufacturing and implanting tissues or materials for correcting corneal geometry with higher precision than existing technologies.

[0009] The optical function of the cornea (also known as the cornea) should be improved by means of the optimized target geometry sought through the apparatus and method described in the invention, while simultaneously establishing or reconstructing a near-normal corneal geometry.

[0010] These measures or features should result in improvements in implant shape (to avoid cavities) and improved manufacturing precision. Therefore, the object of the present invention is, in particular, to: optimally prepare the periphery of (natural or artificial) tissue or material for manual process steps, or to simplify critical process steps by laser processing, or, where possible, to replace them, and to describe measures aimed at improving laser processing precision and reducing implant load or damage.

[0011] However, before describing these groupings in detail, some terms should be explained:

[0012] - An "implant" is tissue, in particular (possibly modified) corneal tissue from a donor eye, or artificial tissue or material of non-human origin with the same properties.

[0013] - "Graft" is human-derived tissue. (The distinction based on the number of living cells it contains may be relevant for regulatory purposes, but is ignored here.)

[0014] - "Implant" means to insert implants and grafts.

[0015] - "Burnt material" refers to a blank. The blank can be an implant or graft, typically having a three-dimensionally curved circular basic shape with a diameter of approximately 5-9 mm and a thickness between 10 μm and 400 μm, up to a maximum of 500 μm. The thickness profile of this spherical shell or similar formation with a radius of curvature between 5 mm and infinity has not yet been matched to the recipient's eye. A sheet is generated from the blank through processing.

[0016] - "Thin sheet" means: an implant or graft manufactured from a blank and specifically matched to the thickness profile of the recipient's eye. Therefore, a thin sheet is the final product, prepared for introduction into the cornea of ​​the recipient's eye into a prepared cut surface or a cavity (structure) defined by the cut surface.

[0017] - A "vacancy" refers to a structure in the stromal bed formed by excision (i.e., removal of corneal volume). A vacancy can also be called an excised cavity, although it never actually exists as a cavity in the cornea, but rather a thin sheet that always largely adheres to the stromal bed and is rapidly filled with tissue fluid, as does the cavity that was initially formed.

[0018] This objective is achieved by a planning device according to the invention for generating control data for a treatment system used in refractive surgery, particularly keratotomy. The planning device includes a first laser device and at least one characterization device, wherein the first laser device, preferably a femtosecond laser device, can be controlled by means of control data to generate at least one cutting surface in the cornea of ​​the eye. The purpose fulfilled by the first laser device requires that its output processing laser beam enter the eye tissue, particularly the cornea, and generate a cutting surface within the tissue. Typically, a laser device is suitable for this purpose, whose processing laser beam can generate optical destruction of the tissue at its focal point.

[0019] The planning device also has:

[0020] - An interface for transmitting initial measurement data regarding corneal parameters to a characterization device, preferably an OCT (Optical Coherence Tomography) device.

[0021] - An interface for transmitting second measurement or model data of a thin film, which can be introduced into the cornea after the cut surface has been generated.

[0022] - An interface for transmitting control data to the first laser device, and

[0023] - A computing mechanism for determining at least one cutting surface in the cornea using first measurement data and second measurement data or model data, wherein the computing mechanism generates a control dataset for manipulating a first laser device, wherein at least one cutting surface can be generated by means of the control dataset through the first laser device.

[0024] Here, the at least one cut surface to be generated in the cornea of ​​the eye, i.e. the recipient eye, can be natural and actually only have a normally curved surface into which the sheet can "slide". However, the volume can also be rewritten by multiple cut surfaces, i.e., the volume can be extracted to subsequently introduce the sheet into the resulting vacancy.

[0025] The planning device is also designed to generate control data for a second laser device, preferably an excimer laser device, for the treatment system to process the blank into a patient-specific shaped sheet. It has an interface for transmitting control data to the second laser device. The first laser device, the second laser device, and the characterization device each have a device coordinate system, and are mutually coupled or capable of being coupled to each other by means of recording in the device coordinate system. They are also capable of recording the transmitted second measurement data or model data of the sheet relative to the device coordinate system. The second laser device is required to perform tasks whereby the output processing laser beam can be dissected from the surface of eye tissue, particularly the cornea, and penetrate into the tissue. While processing laser beams that generate photodestruction within the tissue can certainly be used, a laser device capable of ablating the tissue using its own processing laser beam is particularly suitable for this purpose.

[0026] The fabrication of the preform, for example using an excimer laser device, is also performed such that the processing profile of the laser device (energy density or laser beam distribution as a function of position) is precisely "placed" on the preform, which typically requires centering with an accuracy of approximately 100 μm. Thus, the preform becomes a patient-specific film, and the implantation of the film leads to intentional recording of thickness measurements and possible refractive adaptation.

[0027] The overall planning of the surgery is of great importance. Therefore, a planning method is executed using a planning device, which is coded in embedded software within the planning device. For this purpose, corneal tomography data of the eye to be treated and possibly other biometric parameters (such as radius of curvature, refractive power) are used as inputs to the planning software. Therefore, the planning device in which the planning software is coded can be an integrated component of the treatment system, or it can be distributed and located on one or more computers spatially separate from the treatment system.

[0028] Here, the software displays to the user a thickness measurement method for the patient's resolvable position and at least one other positional marker (e.g., the midpoint of the pupil of clear vision or the corneal visual center, vertex position, limbus). Additionally, the software contains information on a typical patch map of a healthy eye. The software automatically generates a difference map by correctly calculating the difference between the existing patch map and the typical patch map. The user decides whether the method should be performed with or without vacancy, defining the treatment area (typically circular) by, for example, defining the center and diameter of the vacancy, and defining other geometric parameters, such as the diameter and edge thickness of the vacancy, the edge thickness of the vacancy, and the depth of the bag-like incision below the corneal surface. The software can also automatically suggest or determine some or all of these parameters. The software then generates control data for a first laser device, preferably a femtosecond laser device, and for a second laser device, preferably an excimer laser device.

[0029] Depending on the state of the blank to be used for processing a patient-specific film, it is particularly advantageous that the planning device according to the invention is also designed to generate control data for a first laser device or another laser device, preferably a femtosecond laser device, whose device coordinate system is also coupled to the previously proposed device coordinate system by means of recording, in order to generate or pre-process the blank, wherein the blank can be generated from a natural donor cornea or artificial tissue, or can be generated or pre-processed in a natural donor cornea or artificial tissue by means of the first laser device or another laser device to generate one or more cutting surfaces in a natural donor cornea or artificial tissue.

[0030] Control data may and should include recorded information, particularly:

[0031] 1. For example, control data for a femtosecond laser device, which serves as another laser device for pre-processing to generate blanks in raw materials, which may be used, if necessary, to generate blanks in the cornea of ​​a donor eye or in artificial tissue. If the raw materials are already present in a suitable configuration, this step can be replaced by data feed-in regarding the material geometry.

[0032] 2. Control data for, for example, an excimer laser device, which serves as a second laser device for post-processing of a blank into a sheet.

[0033] 3. Control data for generating at least one cutting surface, for example for recording a bag incision or void in the recipient's eye of a thin sheet, the control data being used, for example, for a femtosecond laser device as a first laser device.

[0034] A preferred embodiment of the planning device according to the invention is designed to generate control data for temperature management, so as to keep the temperature below the maximum temperature used for processing a blank into sheets by means of a second laser device. Processing a blank into sheets by means of ablation by a second laser device typically causes the tissue to be processed to heat up due to high energy input. However, in order to ensure accurate structuring, the processing temperature of the tissue should not fluctuate, but rather be kept constant at a low temperature.

[0035] In one variation of the invention, the workpiece is actively cooled before and / or during processing using a second laser device, typically an excimer laser device. In a particular variation of the invention, cooling is performed to below 10 degrees Celsius. In another variation of the invention, cooling is performed to below the freezing point of the workpiece. Processing byproducts are actively removed by means of a controlled airflow. In one variation of the invention, the airflow is actively controlled in terms of temperature and / or humidity. In one variation of the invention, cooling is performed to the dew point of the air in the airflow. In another variation of the invention, an industrial gas (e.g., nitrogen) is used instead of air. In yet another variation of the invention, processing is monitored continuously or cyclically. The monitored parameters are, for example, surface temperature, peel volume, material thickness, surface morphology, and the axial and lateral position of the workpiece. In one design of the invention, the monitored parameters are used to regulate the peeling process.

[0036] One important consideration when planning (and subsequently executing) the generation of patient-specific films with the highest precision involves setting up different blanking zones and subsequent films.

[0037] Therefore, it is highly advantageous that the planning device is designed to define a substantially annular transition zone at the edge of the sheet, within which the edge thickness gradually transitions to a patient-specific thickness profile, and also to generate control data in such a way that the edge of the sheet is not processed by a second laser device, wherein the second laser device has a support for processing the blank into a patient-specific shaped sheet, and the blank can be secured to the support during processing by the second laser device.

[0038] In one embodiment, when the support is used to process a blank using a second laser device, the planning device is designed to generate control data for actively cooling the support.

[0039] If the blank does not yet have suitable dimensions for processing with the aid of a second laser device, in an advantageous first variant, the planning device is designed to determine the cutting surface in the donor cornea or artificial tissue, generate control data, and transmit the control data to a first laser device or another laser device, with the aid of which the blank can be generated. The blank is defined by a correction zone located at the center of the blank, a transition zone surrounding the correction zone, and an edge zone surrounding the transition zone. The edge zone is configured for subsequent separation before the sheet is introduced into the cornea of ​​the eye. The blank can be extracted from the donor cornea or artificial tissue and secured to a support for processing with the aid of the second laser device.

[0040] In a favorable second variant, the planning device is designed to determine the cutting surface in the donor cornea or artificial tissue, generate control data and transmit the control data to a first laser device or another laser device, and generate a blank with the aid of the control data. The blank is defined by a calibration zone located at the center of the blank and a transition zone set around the calibration zone, and the blank can be mechanically processed in the original donor cornea or artificial tissue with the aid of a second laser device.

[0041] The second variant also has the advantage that the planning device is designed to determine the cutting surface in the donor cornea or artificial tissue, generate control data and transmit the control data to a first laser device or another laser device, and generate a blank with the help of the control data. The blank also has an edge region set around the transition zone, which is set for subsequent separation before the sheet is introduced into the cornea of ​​the eye.

[0042] The typical size of the corresponding region is:

[0043] - For the diameter of the correction zone: 3mm to 8mm;

[0044] - For the width (radial) of the transition zone: at least 10 μm, preferably between 50 μm and 2 mm;

[0045] -For the width of the edge area: 0 to 1 mm;

[0046] - For edge thickness: 1 μm to 50 μm. Here, edge thickness refers to the thickness to be achieved, especially in the 10 μm edge region of the outer ring of the sheet.

[0047] Here, the correction zone, transition zone, and edge zone are typically circular or annular. However, depending on the specific patient, elliptical or irregular shapes are also possible. This shape can also be used to correctly position the slit angle within the cornea of ​​the eye.

[0048] It should be noted that currently, there is no technology available for generating defined edge geometries in patient-specific shaped sheets. The femtosecond laser cutting and subsequent excimer laser processing used in experimental methods to create patient-specific shaped sheets cannot generate precise edge geometries; the femtosecond laser cutting is used to generate approximately cylindrical blanks (strictly speaking, blanks represent the cap of a spherical shell). This can be based on the fact that, without the special measures described herein, the edge thickness may randomly deviate from the target value up to 30 μm or up to 100%. Therefore, edge regions according to the invention, for example, for later separation, are also advantageous.

[0049] The use of Zernickel polynomials up to order 6 for patient-specific adaptations via an excimer laser device as a second laser is a significant limitation of this method. Although 10th-order Zernickel decompositions exist in morphology-guided treatments using excimer laser devices, such as MEL, this treatment method has not yet been used in donors, and no practical processing method using this method is currently available. Therefore, there are currently no other proven techniques for manipulating excimer laser devices during ex vivo sheet processing.

[0050] Although the goal of treating corneas with excimer lasers outside the body was set as early as the late 1980s, and there were practical attempts at implementation (P. Homolka et al., Laser-Assisted Orthokeratology (ELCS) System, Electronics and Information Technology, 117, (2000)), this approach has not been implemented in clinical practice. This failure is due in part to the immaturity of excimer laser technology, but also to the lack of modern diagnostic options, such as high-resolution OCT equipment. Furthermore, only mechanical microkeratomes are available to generate the preform, with processing precision an order of magnitude lower than that of today's femtosecond laser systems. Therefore, in addition to the approximately 10 μm graft roughness caused by excimer technology, the precise initial shape of the processed donor cornea remains uncertain. This lack of accuracy hinders the practical application of the generated grafts.

[0051] In sIALK, a sheet with an edge thickness of at least 30 μm is currently used. This is significant for the mechanical strength and manufacturability of the sheet, although it can lead to the formation of annular cavities at the contact points of the matrix, sheet, and cap if vacancies occur. Although air is filled with tissue fluid, it is non-physiological and should be avoided whenever possible. Currently, there is no technique for creating a specific edge geometry for the sheet.

[0052] When the spatial frequency is higher than the beam diameter, it is difficult to manufacture precise geometries using excimer lasers. The fabrication of simple cylindrical blanks using femtosecond lasers has demonstrated that, in principle, it is possible to generate precise edges using femtosecond lasers. Therefore, a combination of processing steps is proposed, using a femtosecond laser as a pre-processing second laser and an excimer laser as a post-processing second laser. However, it is important to note that the processing principles described herein must be planned accordingly and translated into control data.

[0053] The planning device according to the invention for controlling the control data of a treatment system for refractive surgery, particularly keratomileusis, is specifically designed, for example, to generate control data for a second laser device, such that a defined edge geometry is achieved in a patient-specific shaped film, wherein...

[0054] - In the case of a bag cut, and thus without creating voids, the edge thickness is at most 30 μm, preferably between 5 μm and 15 μm, or

[0055] - In the case of removing corneal volume to create a vacancy, the edge thickness of the film matches the geometry of the vacancy.

[0056] Therefore, it is also advantageously designed to define a substantially annular transition zone at the edge of the sheet, within which the edge thickness gradually transitions to a patient-specific thickness profile, thereby generating control data so that the edge of the sheet is not processed by a second laser device.

[0057] Therefore, the edges of the sheet should be substantially generated during the blanking process using a femtosecond laser device as a first or other laser device for pre-processing, while the actual processing / personalization of the sheet before implantation into the recipient's eye is performed, for example, by an excimer laser device as a second laser device for post-processing.

[0058] When viewed along the axial direction, the implant according to the invention has a preferably circular central correction zone. In this zone, the implant is thus shaped such that it achieves, as well as possible, the desired correction in the thickness profile, morphology, or wavefront of the cornea. The correction zone is surrounded by an annular transition zone, which serves to ensure a continuous transition of shape towards the edge zone at the edge of the correction zone. This same annular zone extends to the outer edge of the implant with the highest possible constant height (thickness). It is also possible to eliminate the edge zone, thereby eliminating the advantages associated with it. This is because the purpose of the edge zone is to minimize or at least reduce the effect of centering errors during sequential laser processing on the thickness of the outer edge of the implant. Another purpose of the (extended) edge is to protect the closer edge zone of the (almost completed) sheet until its implantation, as will be detailed below.

[0059] The primary consideration is that if the coordinate systems of the first laser device, the characterization device, and the second laser device are coupled via a planning device using recording, and the second measurement data transmitted to the sheet can be recorded independently relative to the coordinate systems, then measures for defining the sheet's edges and managing its temperature are particularly effective. However, even without such mutual coupling and recording, measures for defining the sheet's edges and managing its temperature during processing, with improved corneal optical functions compared to the prior art, contribute to improved accuracy compared to the prior art and are especially helpful in reconstructing normal corneal geometry.

[0060] As already described, an annular transition zone is provided at the edge, the radial width of which is at least 10 μm, preferably between 50 μm and 2 mm, and particularly preferably between 50 μm and 500 μm. Within the transition zone, the edge thickness gradually transitions to a patient-specific thickness profile. In the simplest case, this is accomplished by a linear connection between the edge thickness D(r = r_max, Phi) and D(r = r_max - edge width, Phi). Other design options that will be obvious to those skilled in the art include smoothing in Phi.

[0061] The edge thickness and contour within the transition zone are achieved, for example, through the cooperation of a femtosecond laser device as a first or second laser device for pre-processing and an excimer laser device as a second laser device for post-processing. Specifically, in a variant of the invention, excimer processing is performed such that excimer ablation is not performed at the edges of the blank. On the one hand, it is necessary to prevent alteration of the edge thickness precisely generated by the femtosecond laser device via the excimer laser device; on the other hand, if the blank is secured to a support by the excimer laser device, ablation of the blank support should not be performed, as this would contaminate the sheet. To further improve this aspect, in a variant of the invention, the transition zone is generated wholly or partially by the femtosecond laser device as the first or second laser device for pre-processing, for example, by generating a tapered basic geometry for the edge region of the blank.

[0062] Currently, in the off-bulk processing of thin sheets, the control of the excimer laser device is achieved by bombardment modes that decompose the differential profile into individual ablation volumes through Zernike unfolding. Currently, this unfolding is only performed up to the 6th order of the polynomial. However, to generate finer structures, unfolding beyond the 6th order is meaningful in off-bulk processing. Of course, performing this unfolding is not mandatory. Instead, the differential profile can be directly decomposed into individual ablation volumes (bombardment decomposition). In any case, the crucial factor is that the processing is performed so that the workpiece temperature does not exceed 40°C. For this purpose, the bombardment distribution and laser frequency of the scanning laser are adapted accordingly.

[0063] Furthermore, the following should be noted regarding the prior art, its problems, and the resulting measures according to the invention:

[0064] Improvements in corneal thickness-related changes in spectacle visual acuity (CDVA) are already a good outcome for the patient. In principle, refractive correction is an option to achieve good uncorrected visual acuity (UCVA), but photorefractive keratotomy (PRK) is always associated with loss of Bowman's membrane, a medically problematic option in biomechanically unstable eyes. Laser-assisted in situ keratomileusis (LASIK) is not feasible due to even greater biomechanical effects, and small-incision lens extraction (SMILE) is practically impossible surgically. Anterior chamber lenses are considered, but they are high-risk for this patient; the same applies to intraocular lenses (IOLs), which in this case replace the non-transparent lens (transparent lens replacement).

[0065] The goal is simply to record corneal thickness (thickness measurement) to achieve a state where the patient's eye has good vision with the aid of a visual aid (glasses, contact lenses). If a better approach is desired, i.e., to achieve good vision without, for example, glasses, additional measures are required. Some basic features for addressing this problem have been partially outlined in DE 10 2007 019 815 A1 and WO 2008 / 131888A1, but no specific or even advantageous design has been known to date.

[0066] Therefore, an advantageous planning device is designed to generate control data for a second laser device, thereby imparting refractive power and / or astigmatism to the blank.

[0067] To enable more precise interaction between the second laser device and the first or other laser device used for preparing the blank, it is particularly advantageous that the planning device according to the invention is designed to define the position of calibration marks in the transition and / or edge regions and generate control data for the first or other laser device, enabling the calibration marks to be introduced by means of the control data during processing with the first or other laser device, wherein the calibration marks are defined such that they can be used as single or multiple redirections during blank processing with the second laser device.

[0068] Particularly helpful is that the planning device according to the invention defines calibration marks, which are set in the blank to be processed by the second laser device in a manner that overlaps and / or offsets and / or at different heights.

[0069] Therefore, as an optional step according to the invention when cutting a blank in a donor cornea or artificial tissue, for example using a femtosecond laser device, a calibration incision can be introduced. Particularly advantageous here are the calibration incisions in the hollowed-out volume, which are also described herein.

[0070] As an alternative incision when processing is performed using, for example, an ablation excimer laser as a second laser device, processing can be interrupted and then resumed after visual inspection by the user. Here, the user specifically checks whether one or more calibration marks have been hit by the excimer treatment and decides accordingly whether to continue the ablation. This method can also be automated using appropriate image recording and processing equipment, wherein the automation is implemented by a controller with corresponding software.

[0071] Typically, processing using an ablation excimer laser can be performed in different stages, such as a first stage for removing epithelium and a second stage for processing stromal tissue.

[0072] Specifically, for example, as shown in some embodiments, calibration marks are introduced into the hollow volume. If this is done in a tool that generates another cut surface, for example using a femtosecond laser as the first or another laser device, the calibration marks can be positioned very precisely relative to the other cut surfaces. Axial and lateral accuracy better than 1 μm is achievable. If, as a result, the excimer glass reaches the calibration mark when processing the blank using, for example, an excimer laser as the second laser device, a very distinctive change in the optical appearance of the corresponding calibration mark is observed, wherein the calibration mark remains in the tissue for a period of time as a cut surface filled with air bubbles. In this way, an optimized superposition of the two laser processing methods can be achieved through the specialized geometry of the calibration mark and the ablation profile, particularly the geometry in the hollow volume, thereby enabling, for example, the production of precise edge thicknesses with low cost.

[0073] As already indicated, it is also advantageous that the planning device is designed to define the machining contour and determine the control data for the second laser device, enabling the generation of the contour of a correction zone located at the center of the workpiece and a transition zone surrounding the correction zone by means of the second laser device, and enabling the generation of a hollowed-out portion in the edge zone surrounding the transition zone.

[0074] - To remove the thin film processed from the donor's cornea or artificial tissue, or

[0075] - To further process the blank on the support so that the support is not hit by the processing laser beam of the second laser device.

[0076] Creating a recess within the method for manufacturing an implant in the form of a patient-specific film is an important part of the invention. The creation of a generally annular cavity around the periphery of the implant is referred to as a recess. The groove-shaped cavity serves to make it easier for the surgeon to expose the implant during dissection, or to carefully remove unwanted material from the periphery of the implant once it has been exposed. This prevents damage to the extremely fine edge structure of the material in the corresponding cut surfaces or structures where the film is introduced into the recipient's cornea. Some characteristic features of the recess are further illustrated in the accompanying drawings of the embodiments.

[0077] Here, the typical value for the width (radial) of the cutout is 500 μm to 3 mm.

[0078] Here, the diameter of any additional cavitation incision that may be performed should be at least 100 μm larger than the diameter of the actual implant, i.e., the final slice.

[0079] It should also be mentioned in this invention that, in order to give a true order of magnitude, calibration cuts are generated in up to hundreds of faces in order to generate the aforementioned calibration marks.

[0080] Furthermore, it is advantageous that the planning device according to the invention is designed to take into account the defined initial hydration state of the blank or sheet outside the body and the changes in the hydration state of the sheet during or after implantation in order to generate control data, preferably by means of a constant expansion factor.

[0081] In corneal transplantation, the problem of varying hydration levels is known and has been mitigated through specific graft processing. However, this problem is first presented in this form in relation to sILAK because, until now, the cornea has not been ex vivo shaped in a patient-specific manner, for example, using an excimer laser device. Here, the ablation efficiency of the excimer laser device, which varies with hydration, also causes swelling and contraction.

[0082] In analyzing the treatment methods used to date, the variability of the material, especially its hydration state, has been noted, as this can be a source of significant errors. This is not yet clear, and appropriate measures are needed to eventually enable more precise pre-determination of the geometry, and particularly the thickness, of the lamina in the recipient cornea.

[0083] Another possibility for improving the examination of hydration status is to use artificial tissue material with well-defined parameters, from which a thin sheet to be implanted can then be processed in a controlled manner using a second laser device, serving as an alternative to natural transplant material.

[0084] In addition, blanks or sheets can be colored with dyes to improve processing, and the dyes gradually disappear after the sheets are implanted.

[0085] This objective is also achieved by a treatment system according to the invention for refractive surgery, particularly keratoconlasty, comprising:

[0086] - A first laser device, preferably a femtosecond laser device, for generating at least one cut surface in the cornea of ​​the eye.

[0087] - A second laser device, preferably an excimer laser device, for processing a blank into a thin sheet with a patient-specific shape.

[0088] - At least one characterization device, preferably an OCT device, and

[0089] -The planning device according to the invention described herein.

[0090] The treatment system according to the invention is advantageous in that it has another laser device, preferably a femtosecond laser device, for generating or pre-processing blanks.

[0091] In one particular design of the treatment system according to the invention, the second laser device includes a support for securing the workpiece during processing.

[0092] A particular design of the treatment system according to the invention includes a temperature regulating device, which preferably reduces the temperature of the blank to enable processing of the blank in a frozen state.

[0093] The blank can then be cooled for machining. Reduced temperature during machining results in more precise machining by minimizing material changes caused by drying and / or temperature variations. The latter is particularly effective when machining at high laser frequencies and when correspondingly rapid and large amounts of energy are input into the blank. This energy input is not always limited to the area of ​​direct interaction between the laser radiation and the material, but can also include the area surrounding the interaction area through heat transfer and heat transport. Since (artificial) materials, especially those manufactured using biotechnology, sometimes react sensitively to temperature increases, i.e., adversely, cooling the blank can provide a remedy in the therapeutic system according to the invention and in one embodiment of the method according to the invention.

[0094] In a preferred design, the temperature of the blank, particularly the blank fastened to a support for processing, drops to approximately the ambient dew point. This means, for example, setting a surface temperature of approximately 9°C in an indoor air temperature of 20°C and an air humidity of 50%.

[0095] In a particularly preferred design, the temperature of the blank on the support is reduced to the point of freezing. This reduction in blank temperature below its freezing point can be achieved, even in normal indoor air conditions, using a correspondingly cold support. Laser processing is then performed on the frozen blank. For example, the blank temperature can be reduced to below 0°C, below -5°C, or below -10°C. The advantage of this extremely low temperature is reduced interaction between laser radiation and the unablated material. Condensation or frosting of the material is minimized by a rapid process (e.g., complete laser processing in less than one minute) or compensated for by a suitably designed ablation process.

[0096] In a specific treatment system according to the invention, the temperature regulating device has at least one of the following designs:

[0097] -Active electric cooling is achieved using Peltier elements.

[0098] -Active cooling is achieved by introducing a coolant.

[0099] -Active cooling via airflow.

[0100] - Passive cooling is achieved by pre-cooling the support, which may or may not have a blank fastened to it.

[0101] - A chamber separated from the environment for processing blanks.

[0102] Therefore, the support can be equipped with a cooling mechanism for cooling purposes. For example, the cooling mechanism is an active electric cooling device using Peltier elements. However, it is also possible to consider active cooling by means of an introduced coolant (e.g., nitrogen, ethylene glycol, ethanol) or passive pre-cooling in a correspondingly cold environment (refrigerator). Cooling can be regulated, wherein the temperature of the support or the temperature of the blank are monitored in the appropriate implementation of the support.

[0103] Instead of normal indoor air (23°C, 50% relative humidity), the workpiece can also be loaded with airflow, which, in addition to its usual function of removing debris, also affects the workpiece temperature. This is achieved by adjusting the temperature and / or air humidity. Optionally, a protective gas can be used instead of indoor air. To further improve this method, the workpiece can be processed in a chamber separated from the environment.

[0104] As a guideline for the specific machining of blanks on a support in a second laser device, particularly an excimer laser device, the following design can be used to carry out the work:

[0105] - For frost-free operation, the temperature of the support should be approximately 1°C to 20°C.

[0106] - For "frost operation", the temperature of the support should be approximately -30°C to -1°C.

[0107] Another advantage of the treatment system according to the invention is that it has a device for monitoring the temperature of the blank and / or the support during processing.

[0108] This objective is also achieved by the planning method according to the invention, which generates control data for a treatment system for refractive surgery, particularly keratotomy, based on the encoding of the described planning device.

[0109] Last but not least, the object of the invention is achieved by a method of refractive surgery, particularly keratotomy, wherein at least one cut surface is generated in the cornea of ​​the eye, a sheet for introduction into the cornea of ​​the (recipient) eye is planned by means of the described planning method, manufactured by means of the generated control data and introduced into at least one cut surface in the cornea of ​​the eye, and, if necessary, also into the vacancy formed by the cut surface.

[0110] Here, one of the following method variations can be used when manufacturing the sheet.

[0111] Variant 1:

[0112] 1. Using a first or second laser device, particularly a femtosecond laser device (also known as a femtosecond laser corneal cutter), a blank is cut in the donor cornea or artificial tissue.

[0113] 2. Using a second laser device, particularly an excimer laser device, the blank in the donor cornea or artificial tissue is processed to generate a correction zone, a transition zone, and an edge zone, and, if necessary, to introduce a cutout to expose the implant (i.e., the nearly completed sheet).

[0114] 3. The implant is removed from the donor's cornea or artificial tissue.

[0115] Variant 2:

[0116] 1. Using a first or second laser device, particularly a femtosecond laser device, to cut blanks in the donor cornea or artificial tissue.

[0117] 2. Remove the blank from the donor's cornea or artificial tissue and position it on the scaffold.

[0118] 3. The blank on the support is processed with the aid of a second laser device, especially an excimer laser device, to generate the correction zone, transition zone and edge zone, and, if necessary, to introduce a hollowed-out section.

[0119] 4. Optionally: Separate the implant (i.e., the final patient-specific film from the rest of the blank).

[0120] Variant 3:

[0121] 1. Position the blank (made of donor corneal material or artificial tissue material) on the scaffold.

[0122] 2. Optional: Start cooling bracket.

[0123] 3. The blank on the support is processed using a second laser device, particularly an excimer laser device, and optionally a first or another laser device, particularly a femtosecond laser device (femtosecond laser corneal knife), to generate the correction zone, transition zone, and edge zone. A hollow section is introduced.

[0124] 4. Optionally: Separate the implant from the stent after heating the stent.

[0125] Variant 4:

[0126] 1. Implement one of the variant schemes 1 to 3.

[0127] 2. Separate the implant from the stent.

[0128] 3. Flip (i.e. invert) implant (spherical volume can be "flipped" / inverted).

[0129] 4. Position the implant on the stent, where the upper part is now located at the lower part.

[0130] 5. The rinsing can perform one of the variations 1 to 3. Attached Figure Description

[0131] The invention will now be explained with reference to embodiments. These embodiments show:

[0132] - Figure 1a A schematic diagram of a preferred first treatment system according to the invention, having a first planning device according to the invention, is shown, but it does not reflect the exact physical conditions.

[0133] - Figure 1b A schematic diagram of a preferred second treatment system according to the invention, having a second planning device according to the invention, is shown.

[0134] - Figure 1c A schematic diagram of a preferred third treatment system according to the invention, having a third planning device according to the invention, is shown.

[0135] - Figures 2a to 2f Regarding the process of generating an implant / patient-specific film, for example, by means of the planning device according to the invention, i.e., the principle of processing the blank until the complete generation of the patient-specific film within the donor cornea or artificial tissue, different processing stages and processing variations of the blank in the donor cornea or artificial tissue are shown.

[0136] - Figures 3a to 3f Regarding the process of generating an implant / patient-specific sheet, for example, by means of the planning device according to the invention, that is, regarding the principle of further processing the blank by means of a second laser device, specifically an excimer laser device, to extract the blank from the donor cornea or artificial tissue and fix it on the scaffold, different processing stages and processing variations of the blank in the donor cornea or artificial tissue are shown.

[0137] - Figures 4a to 4c The implant is shown after processing with a laser device according to the treatment system of the invention and before it is introduced into the cut surface of the cornea of ​​the recipient's eye. Detailed Implementation

[0138] In all Figures 1a to 1c In this treatment system 1, there are: a planning device 2; a characterization device 4 designed to generate measurement data on parameters of the cornea 20 of the eye by means of examination radiation 8; and a first laser device 3, which is a femtosecond laser device and designed to generate vacancy or, as shown, a pouch incision 21 in the cornea 20 of the recipient eye by means of a focused femtosecond laser beam 9 (the incident direction of the beam is not shown here, however, those skilled in the art will know the optical structure of the corresponding device).

[0139] All characterization and laser devices in treatment system 1 include an interface 5 to planning device 2.

[0140] Figure 1a and Figure 1b It also includes another laser device 6 for pre-processing, which is also a femtosecond laser device. The first femtosecond laser device 3 and the other femtosecond laser device for pre-processing are the same device, but they can also be two different laser devices. The other laser device for pre-processing cuts out a blank 23 from the cornea of ​​the donor eye 22 using a focused femtosecond laser beam 10. Figures 1a to 1c It also includes a second laser device for post-treatment, namely the excimer laser device 7, which uses excimer laser radiation 11 to process a thin film 24 to be implanted from a blank 23. The film is then finally implanted into the corneal pouch 21 of the recipient's eye 20.

[0141] The planning device 2 is designed to couple the device coordinate systems of the participating laser devices 3, 6, 7 and characterization device 4 by means of recording, and to record the measurement data transmitted by the thin film to be implanted separately with the device coordinate system.

[0142] And in Figure 1aFirst, a pouch-shaped incision 21 is formed in the cornea of ​​the recipient eye 20, and then a blank 23 is formed and removed from the donor eye so that the blank can be then shaped into a sheet 24, as it should preferably be operated, first in Figure 1b The blank 23 is completely processed into a thin sheet 24. Then, a bag incision 21 is made in the cornea of ​​the recipient's eye 20 in preparation for implantation.

[0143] Again Figure 1c In this process, work is carried out using a standardized blank 23 (preferably made of artificial tissue material), which is then further processed into a sheet 24. However, it is also shown here that during the processing of the blank using an excimer laser device 7, which serves as a second laser device, the blank 23 is also secured to a support 25. The support is cooled during the processing of the blank.

[0144] Figures 2a to 2f Regarding the process of generating an implant / patient-specific film 24 by means of, for example, the planning device 2 according to the invention, i.e., the principle of processing the blank 23 until the patient-specific film 24 is generated in the donor cornea or artificial tissue, different processing stages and processing variations of the blank 23 in the donor cornea or artificial tissue are shown.

[0145] Here, in Figure 2a The donor cornea and its various layers are shown, namely the epithelial layer 101, the Bowman membrane 102, and the corneal stroma 103. In addition, the incisions that fundamentally separate the blank 23 from the donor cornea are shown, namely the lamellar cut 104 and the marginal cut 105.

[0146] exist Figure 2b The image also shows an implant 106 to be created in the form of a patient-specific sheet 24 and a subsequent ablation volume 107, which should be ablated using a second laser device 7. A cutout 108 is also shown, which is later used to simplify the separation of the implant 106 from the donor cornea (or artificial tissue). Figure 2b It can also be seen that: the two outer boundaries of the correction areas 109 and 110, and the outer boundary of the upper part of the implant 111, the outer boundary of the upper part being the intersection of the edge incision 105 and the upper side of the final implant.

[0147] Apart from Figure 2a and Figure 2b In addition to the areas, incisions, and markings mentioned in the text, Figure 2c The outer limits of transition zones 112 and 113 are shown in the figure.

[0148] In addition to Figures 2a to 2c In addition to the areas, incisions, and markings already mentioned, Figure 2d Calibration mark 114 is also shown. With the aid of the calibration mark, it is possible, for example, to calibrate relative to the cutout. Figure 2b and Figure 2c The shape 115 shown in the figure is used to change the shape of the hollow part: by introducing a calibration mark 114 by means of a first laser device 3 or another laser device 6 (i.e., a femtosecond laser device), and then controlling the ablation profile in the edge region during the ablation process by means of a second laser device 7 (here, an excimer laser device).

[0149] In addition to the calibration mark 114 already mentioned, Figure 2e Additional calibration marks are shown: calibration marks on the implant in its edge region 116 and calibration marks next to the implant, as well as stacked calibration marks 117, 118.

[0150] In addition, Figure 2f The plan also includes the use of a first laser device 3 or another laser device 9, namely a femtosecond laser device, to generate an edge incision 119, thereby allowing the height of the implant 106 in its edge region, especially the height of the patient-specific sheet 24, to be more reliably determined as the final product of the planning and processing of the blank 23 compared to when the height is generated solely by ablation using a second laser device 7, an excimer laser device.

[0151] Therefore, in Figures 2a to 2f In a variant, a patient-specific thin film 24 from the donor cornea is machined from the blank 23. Only after this machining is the implant 106 removed from the donor cornea or artificial tissue.

[0152] Figures 3a to 3f Regarding the process of generating an implant / patient-specific sheet 24, for example, by means of the planning device 2 according to the invention, i.e., a principle variation of further processing of the blank by means of the second laser device 7, i.e., the excimer laser device, to extract the blank 23 from the artificial tissue and fix it onto the scaffold 25, different processing stages and processing variations of the blank 23 in the donor cornea or artificial tissue are shown. This method is particularly preferred when processing artificial tissue because, when secured to the scaffold 25 during processing by means of the second laser device 7, i.e., the excimer laser device, safe temperature management must be ensured, as artificial tissue is even more sensitive in this respect than the natural tissue of the donor cornea.

[0153] Here, in Figure 3aThe diagram first shows artificial tissue, which is "reconstructed" from a natural cornea having an epithelial layer 101, Bowman's membrane 102, and corneal stroma 103. Furthermore, it shows incisions that completely separate the blank 23 from the artificial tissue: a lamellar cut 104 and a side cut 105, in which the side cut, in this case, does not extend into the epithelial layer 101 from the lamellar cut 104, but only into the stroma. However, the blank 23 is only truly separated from the artificial tissue by a modified side cut 120.

[0154] exist Figure 3b In addition to Figure 3a In addition to the areas, incisions, and markings already mentioned, the implant 106 to be generated, in the form of a personalized sheet, is shown, followed by the ablation volume 107 and the hollow portion 108. Particularly noteworthy is the hollow portion 108: the edge incision 120 of the knee is designed such that the hollow portion 108 is completely enclosed within the blank 23 separated from the artificial tissue by cutting. Figure 3b It can also be seen that: the two external boundaries of the correction areas 109 and 110, and the external boundary of the upper part of the implant 111, the external boundary of the upper part being the intersection of the edge incision 105 and the upper side of the final implant.

[0155] exist Figure 3c In this process, the blank 23 is first extracted from the artificial tissue and fixed onto the scaffold 25. Besides... Figure 3a and Figure 3b In addition to the areas, cuts, and markings mentioned above, the outer boundaries of transition zones 112 and 113 are also shown here.

[0156] Besides already Figures 3a to 3c In addition to the areas, incisions, and markings already mentioned, Figure 3d Calibration mark 114 is also shown. Here, the shape 115 of the cutout 108 can also be influenced by means of calibration mark 114.

[0157] In addition to the calibration mark 114 already mentioned, Figure 3e Other calibration marks are also shown, namely calibration marks on the implant in its edge region 116, calibration marks next to the implant 106, and stacked calibration marks 117, 118, all of which are more or less the same as those used when processing the preform 23 into a patient-specific slice 24 in the donor cornea. Of course, in this variant, from the moment the preform 23 is fixed to the support 25, temperature management and very precise maintenance can now be introduced when processing the preform 23 with the aid of the second laser device 7, i.e., the excimer laser device.

[0158] In addition, Figure 3fThe plan also includes the use of a first laser device 3 or another laser device 6, namely a femtosecond laser device, to generate an edge incision 119, which reliably determines the height of the implant 106 in its edge region, and in particular, the height of the patient-specific sheet 24 as the final product of the planning and processing of the blank 23.

[0159] at last, Figures 4a to 4c The implant 106 is shown after processing by means of laser devices 3, 7, 6 of the treatment system 1 according to the invention and before it is introduced into the cut surface 21 of the cornea of ​​the recipient's eye.

[0160] exist Figure 4a The top view shows this implant 106, in which the implant blank 23 is processed on the support 25 using a second laser device 7, namely an excimer laser device. Figure 4b and Figure 4c A side view of the same implant 106 is shown. The actual edges of the sheet 24 to be implanted are precisely machined through a cutout. However, the edges are protected until they are processed using the second laser device 7. The separation portion for the final separation widening of the "protective edge" is introduced at the beginning of the entire manufacturing process of the patient-specific sheet 24 via an edge incision ("side cut") in the blank 23. Then, as... Figure 4c As shown, after the “protective edge” is actually separated, the patient-specific sheet 24 is retained and can be introduced into the prepared cut surface 21 or structure in the cornea 20 of the recipient eye.

[0161] Hereinafter, without departing from the scope of the invention, the features of the invention described above and in various embodiments can be used not only in the exemplary combinations illustrated, but also in other combinations or individually.

[0162] The device description associated with the method features is similarly applicable to the corresponding method in terms of these features, while the method features correspondingly represent the functional features of the described device.

Claims

1. A planning device (2) for generating control data for a treatment system (1) for refractive surgery, the treatment system comprising a first laser device (3) and at least one characterization device (4). -in, The first laser device (3) can be controlled by means of the control data to generate at least one cutting surface (21) in the cornea (20) of the eye, wherein the planning device (2) has: - An interface (5) for transmitting first measurement data about the parameters of the cornea (20) to the characterization device (4). - An interface (5) for transmitting second measurement data or model data of a thin film (24), which can be introduced into the cornea (20) after the cut surface (21) is generated. - An interface (5) for transmitting control data to the first laser device (3), and - A computing mechanism, which is configured to determine at least one cutting surface (21) in the cornea (20) for introducing the film into the cornea using the first measurement data and the second measurement data or model data, wherein the computing mechanism generates a control dataset for manipulating the first laser device (3), wherein the control dataset is used to generate at least one cutting surface (21) for introducing the film into the cornea via the first laser device (3). Furthermore, the planning device is also designed to generate control data for the second laser device (7) of the treatment system (1), and the planning device has an interface (5) for transmitting the control data to the second laser device (7), wherein the first laser device (3), the second laser device (7) and the characterization device (4) each have a device coordinate system, and the first laser device, the second laser device and the characterization device are coupled to each other or can be coupled to each other by means of recording in the device coordinate system, and the first laser device, the second laser device and the characterization device can record the second measurement data or model data of the sheet (24) being transported relative to the device coordinate system. Its features are, - The second laser device is designed to process the blank (23) into the patient-specific shaped sheet (24), and The planning device is designed to determine a substantially annular transition zone at the edge of the sheet (24), within which the edge thickness gradually transitions to a patient-specific thickness profile, and also generates control data to avoid processing the edge of the sheet by the second laser device (7). -The second laser device (7) has a support for processing the blank (23) into the patient-specific shaped sheet (24), the blank (23) being secured to the support during processing by the second laser device (7), and The planning device is also designed to generate control data for actively cooling the support within the support itself, and the planning device is designed to generate control data for temperature management to keep the temperature below the maximum temperature used to process the blank into the sheet (24) by the second laser device (7).

2. The planning device (2) according to claim 1, wherein, The refractive surgery in question is keratotomy.

3. The planning device (2) according to claim 1, wherein, The first laser device is a femtosecond laser device.

4. The planning device (2) according to claim 1, wherein, The characterization device is an optical coherence tomography (OCT) device.

5. The planning device (2) according to claim 1, wherein, The second laser device is an excimer laser device.

6. The planning device (2) according to any one of claims 1 to 5, further designed to generate control data for the first laser device (3) or another laser device (6) to generate or pre-process the blank (23), wherein the device coordinate system is also coupled to the device coordinate system of the other laser device by means of recording, wherein, The blank (23) can be generated from a natural donor cornea or artificial tissue by means of the first laser device (3) or the other laser device (6) to generate one or more cutting surfaces in the natural donor cornea or artificial tissue, or the blank can be pre-processed in the natural donor cornea or artificial tissue.

7. The planning device (2) according to claim 6, wherein, The other laser device is a femtosecond laser device.

8. The planning device (2) according to claim 6, the planning device being designed to determine a cutting surface in a donor cornea or artificial tissue, generate control data, and transmit the control data to the first laser device (3) or another laser device (6), using the control data to generate a blank (23), the blank being defined by a correction zone located at the center of the blank (23), a transition zone arranged around the correction zone and an edge zone arranged around the transition zone, the edge zone being configured for subsequent separation before the sheet (24) is introduced into the cornea of ​​the eye, and the blank (23) being able to be extracted and secured to a support (25) for processing using the second laser device (7).

9. The planning device (2) according to claim 6, the planning device being designed to determine a cutting surface in a donor cornea or artificial tissue, generate control data, and transmit the control data to the first laser device (3) or another laser device (6), using the control data to generate a blank (23) defined by a correction zone located at the center of the blank (23) and a transition zone arranged around the correction zone, and to further process the blank (23) in the original donor cornea or artificial tissue using the second laser device (7).

10. The planning device (2) according to claim 9, the planning device being designed to determine a cutting surface in a donor cornea or artificial tissue, generate control data, and transmit the control data to the first laser device (3) or another laser device (6), the control data enabling the generation of a blank (23), the blank further having an edge region arranged around the transition region, the edge region being configured for subsequent separation prior to the introduction of the sheet (24) into the cornea of ​​the eye.

11. The planning device (2) according to claim 8, wherein the planning device is designed to define the positions of calibration marks (114, 117, 118) in the transition zone and / or edge zone, and to generate control data for the first laser device (3) or the other laser device (6), wherein the calibration marks (114, 117, 118) can be placed using the control data during processing using the first laser device (3) or the other laser device (6), wherein, The calibration marks (114, 117, 118) are configured such that they can be used as single or multiple redirections during the processing of the blank (23) by means of the second laser device (7).

12. The planning device (2) according to claim 11, wherein the planning device defines calibration marks (114, 117, 118) arranged superimposed on each other and / or offset from each other and / or at different heights in the blank to be processed by the second laser device (7).

13. The planning device (2) according to any one of claims 1 to 5, the planning device is designed to define the processing profile and determine control data for the second laser device (7), thereby enabling the generation of the profile of the correction zone located at the center of the blank (23) and the profile of the transition zone arranged around the correction zone by means of the second laser device (7), and enabling the generation of a cutout (108) in the edge zone arranged around the transition zone. - To remove the thin film processed from the donor's cornea or artificial tissue (24), or - To further process the blank (23) on the support (25) so that the support (25) cannot be hit by the processing laser beam of the second laser device (7).

14. The planning device (2) according to any one of claims 1 to 5, the planning device being designed to take into account, in order to generate control data, the defined initial hydration state of the blank (23) or the sheet (24) outside the body and the changes in the hydration state of the sheet (24) during or after implantation.

15. The planning device (2) according to claim 14, wherein the planning device is designed to, in order to generate control data, take into account the defined initial hydration state of the blank (23) or the sheet (24) outside the body and the changes in the hydration state of the sheet (24) during or after implantation by means of a constant expansion factor.

16. A treatment system (1) for refractive surgery, said treatment system comprising: - A first laser device (3) for generating at least one cut surface (21) in the cornea (20) of the eye. - A second laser device (7) for processing a blank (23) into a thin sheet (24) with a patient-specific shape. -At least one characterization device (4). The treatment system is characterized by further comprising: - The planning device (2) according to any one of claims 1 to 15, and - The second laser device (7) includes a bracket (25) for securing the blank (23) during processing.

17. The treatment system (1) according to claim 16, wherein the treatment system has another laser device (6) for generating or pre-processing the blank (23).

18. The treatment system (1) according to claim 16 or 17, wherein the treatment system has a temperature regulating device to enable processing of the blank (23) in a frozen state.

19. The treatment system (1) according to claim 18, wherein the treatment system is capable of reducing the temperature of the blank (23) to enable processing of the blank (23) in a frozen state.

20. The treatment system (1) according to claim 18, wherein the temperature regulating device of the treatment system has at least one of the following designs: -Active electric cooling is achieved using Peltier elements. -Active cooling is achieved by introducing a coolant. -Active cooling via airflow. - Passive cooling is achieved by pre-cooling the support (25), which may or may not have a blank (23) fastened to the support. - An environment-separated chamber for processing the blank (23).

21. The treatment system (1) according to claim 16 or 17, the treatment system having means for monitoring the temperature of the blank (23) and / or the temperature of the support (25) during processing.

22. A planning method, said planning method realizing the generation of control data according to the coding of the planning device (2) according to any one of claims 1 to 15, said control data for a treatment system (1) for refractive surgery according to any one of claims 16 to 21.

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