Method for providing control data for an ophthalmic surgical laser, method for controlling a treatment device, control device, treatment device, computer program, computer-readable medium

Abstract

Method for providing control data for an ophthalmic surgical laser, wherein the method comprises the following steps performed by a control device (20): - Determining refractive error data describing a degree of refractive error of a human or animal eye (40) (S1), - Determining an actual geometry of a correction area (32) of a cornea (17) of the eye (40), which describes three-dimensional dimensions of the correction area (32) of the cornea (17) (S2), - based on the determined refractive error data and the determined actual geometry: Determining a target geometry of the correction area (32) that describes a reduction component (44) of the correction area (32) with a corneal thickness reduced compared to the actual geometry, and / or a thickening component (42) with a corneal thickness increased compared to the actual geometry; wherein the determined target geometry fulfills a predefined refractive error reduction criterion that specifies suitability for reducing the degree of refractive error (S3), - Specifying the angle of rotation and the axis of rotation (31) depending on: a) a result of a comparison of the determined actual geometry with the determined target geometry, and / or b) the determined visual impairment data (S5), - based on the determined actual geometry: Determining interfaces (14, 16) of a lenticel (12) within the correction area (32), which extends at least partially over the correction area (32), wherein a portion of the lenticel (12) is designed such that, when the lenticel (12) is rotated (D) into the thickening portion (42) about the specified axis of rotation (31) passing through the cornea (17) and about the specified angle of rotation, it transforms the correction area (32) from the determined actual geometry into the determined target geometry (S4), - Defining at least one incision path as access for an instrument to rotate the lenticule (12), which extends from a predetermined incision site on an outer surface of the cornea (17) to one of the defined interfaces (14, 16) (S7), and - Providing control data that describe the determined interfaces (14, 16) for forming the lenticel (12), the at least one determined incision path, the specified axis of rotation (31) and a rotation of the lenticel (12) about the specified angle of rotation (S6).

Description

[0001] The present invention relates to a method for providing control data for an ophthalmic surgical laser. The ophthalmic surgical laser is controlled for the removal of a volumetric body from a human or animal cornea. The invention further relates to a method for controlling a treatment device, a control unit, a treatment device, a computer program, and a computer-readable medium.

[0002] Devices and methods for controlling photoablative ophthalmic lasers are known in the prior art. As an alternative to laser-assisted in situ keratomileusis (LASIK), small-incision lenticule extraction (SMILE) can be performed, a method of refractory surgery in which a corneal lenticule is removed through a peripheral incision. For example, a pulsed laser and a beam focusing device can be configured such that the laser pulses cause photodisruption in a focus located within the organic material. In cases of symmetrical pathology, i.e., a cornea that is too thick in one area and thus causes refractive error, a portion of the cornea can be removed to correct the refractive error.If the cornea is too thin in one area, a piece of cornea can be extracted from another area and transplanted into the too thin area.

[0003] Femtosecond systems are used in corneal surgery to, for example, transplant part of a cornea (“deep anterior lamellar keratoplasty”, “DALK”), and / or perform penetrating keratoplasty (PKP).

[0004] However, extracting a lenticule is invasive and can thin and weaken the cornea. Transplanting a lenticule is also invasive and can weaken and injure the cornea.

[0005] The article “Intrastromal lenticule rotation for treatment of astigmatism up to 10.00 diopters ex vivo in human corneas” (Damgaard, IB; Ivarsen, A.; Hjortdal, J.; Journal of refractive surgery, Vol. 35, 2019, No. 7, pp. 451-458) describes an assessment of the feasibility of intrasomal lenticule rotation up to 10.00 diopters.

[0006] One of the problems underlying the invention is to reduce corneal weakening when correcting corneal pathology, in particular symmetrical corneal pathology.

[0007] The stated problem is solved by the methods and devices according to the invention as defined in the dependent claims. Advantageous embodiments are described in the sub-claims.

[0008] The invention is based on the idea of ​​determining the shape and position of a lenticule within a correction area of ​​the cornea of ​​the eye with a given geometry, wherein the cornea in the correction area has a portion that is too thick and / or too thin. This lenticule, when rotated by a predetermined angle, reduces the thickness of the excessively thick portion and / or increases the thickness of the excessively thin portion. Preferably, the correction can be performed without extraction; however, depending on the pathology, part of the lenticule can be extracted and only the remainder rotated.

[0009] Preferably, the angle of rotation can also be determined. The angle of rotation can preferably be predetermined based on the corneal pathology.

[0010] In other words, there is no complete extraction of a lenticule, ideally no extraction at all, nor is there any transplantation. Rather, a lenticule is shaped and rotated in such a way that the excessively thick and / or thin portion of the cornea is at least partially compensated for by the rotation. This allows the refractive error to be corrected. The control data provided by the method according to the invention can control a treatment device in such a way that the procedure is less invasive and thus results in less corneal thinning and / or weakening. In other words, the methods and devices according to the invention enable a much gentler and therefore less stressful treatment of the cornea.

[0011] A first aspect concerns a method for providing control data for an ophthalmic surgical laser, wherein the method comprises the following steps performed by a control device. A control device is understood to be a device, a device component, or a group of devices that is configured to receive and evaluate signals, as well as to provide, for example, generate, control data. The control device can be designed, for example, as a control chip, computer program, computer program product, or control unit.

[0012] The control unit determines refractive error data that describes the degree of refractive error in a human or animal eye. This data can describe, for example, ametropia, i.e., a deviation of the refractive power of an eyeball from the ideal value, such as nearsightedness, farsightedness, or astigmatism. The data can also describe, for example, a refractive power value, i.e., a measurement in diopters, or a deviation of corneal curvature from a normal value. The refractive error data can be determined, for example, by retrieving it from a data storage device or server, or it can be received from a measuring device that measures the cornea and / or determines ametropia.

[0013] The control unit determines the actual geometry of a correction area of ​​the eye's cornea, describing the three-dimensional dimensions of this correction area. This actual geometry can be determined, for example, by scanning and measuring the cornea or by providing such measurement data. The actual geometry thus refers to the true, current geometry of the cornea. The correction area is the part of the cornea that is to be corrected to correct or reduce the refractive error.

[0014] Based on the determined refractive error data and the established current geometry, the control unit determines a target geometry for the correction area. This target geometry describes at least one portion of the correction area, specifically at least one portion that has a cornea that is too thick or too thin. This correction portion may already be described by the current geometry or, for example, determined from it. The target geometry thus describes the desired geometry of the areas to be corrected.

[0015] In other words, the target geometry can describe a reduction portion of the correction area with a corneal thickness that is reduced or decreased compared to the actual geometry. In other words, it describes a portion of the cornea that is too thick according to the actual geometry and is corrected by reducing its thickness according to the target geometry. Alternatively or additionally, the target geometry describes a thickening portion with a corneal thickness that is increased compared to the actual geometry. The thickening portion is that part of the cornea that is too thin according to the actual geometry and is to be thickened to correct or reduce the refractive error. The determined target geometry fulfills a predefined refractive error reduction criterion, which specifies its suitability for reducing the degree of refractive error.For this purpose, the specified refractive error reduction criterion can, for example, describe a reduction of refractive error by 0.5 diopters, or a reduction of refractive error by 50% or 100%, or the highest possible reduction of refractive error.

[0016] The control unit specifies the angle and axis of rotation. This is done based on a) the result of a comparison between the measured actual geometry and the determined target geometry, and / or b) the measured refractive error data. In other words, the control unit can calculate, for example, based on the shape of the lenticule and the difference between the actual and target geometry, how far the lenticule must be rotated to compensate for errors in the reduction and / or thickening components. This results in a much more precise correction of the refractive error.

[0017] Based on the determined actual geometry, the control unit identifies the boundary surfaces of a lenticule within the correction area, which extends at least partially over the correction area. A portion of the lenticule is designed such that, when rotated within the thickening portion around the specified axis of rotation passing through the cornea and by the specified angle of rotation, it transforms the correction area from the determined actual geometry to the determined target geometry. A lenticule is understood to be a solid body of the cornea, for example, a disc-shaped disk. The lenticule or solid body can optionally be lens-shaped or, alternatively, bean-shaped. The lenticule can be symmetrically or asymmetrically shaped.The axis of rotation is an axis that passes through a predetermined pivot point of the lenticule, whereby the axis of rotation can, for example, run between the posterior pole of the eyeball and the anterior pole of the eyeball, i.e., it can lie on the optical axis.

[0018] The control unit defines at least one incision path as an access point for an instrument used to rotate the lenticule. This path extends from a predetermined incision site on the outer surface of the cornea to one of the identified interfaces. In other words, the incision path is the path or line used as an access point for an instrument to rotate the lenticule, and optionally, an access point through which, for example, a portion of the lenticule can be extracted.

[0019] The control unit provides control data, meaning it can, for example, generate it. This control data describes the determined interfaces for forming the lenticule. The control data can, for example, describe the coordinates of the interfaces and / or vectors along which the laser is to cut the interfaces. The interfaces can, for example, form a biconvex, biconcave, plano-convex, or plano-concave solid.

[0020] The provided control data also describes at least one defined incision path. This enables particularly precise fine-tuning of the rotated lenticule.

[0021] The provided control data also defines the specified axis of rotation and the rotation of the lenticule around the specified angle. This allows the lenticule to be rotated by the treatment device itself, if it includes a suitable instrument such as tweezers or micro-tweezers. This enables particularly precise fine-tuning of the rotated lenticule.

[0022] The aforementioned advantages result. After rotation through the predetermined angle, the shape of the lenticule contributes to correcting the eye's refractive error. Using the provided control data, an eye laser can be guided to cut and rotate the lenticule accordingly. This rotation compensates for areas of thickening and / or reduction. Complete extraction of the lenticule is unnecessary, significantly reducing corneal weakening. The lenticule can be separated, for example, by laser treatment of the identified interfaces, rotated, and then repositioned. If any part of the lenticule needs to be extracted, it is very small, making partial extraction less invasive than extracting the entire lenticule and performing a lenticule transplant. Ideally, extraction can be avoided altogether.

[0023] Preferably, the control device can determine a target end position of a predetermined lenticule area of ​​the lenticule; in other words, the end position in which a portion of the lenticule should be located after rotation. The provided control data can then describe marking the determined target end position outside the lenticule; and / or the provided control data can describe marking the predetermined lenticule area. In other words, the control data can, for example, describe marking the lenticule at a specific location, for example, by laser-etching a crosshair; and / or the provided control data can describe applying a corresponding mark outside the lenticule, i.e., in the remaining part of the cornea.For example, if both the lenticule area and a point outside the lenticule are marked, the provided control data allows the marking to be performed in such a way that a surgeon knows which lenticule to rotate further so that the mark on the lenticule area aligns with the mark on the corneal body. This not only supports rotation of the lenticule if performed by a surgeon, but the treatment device can also use such markings to verify the optimal position of the rotated lenticule.

[0024] In a training course, the provided control data can describe the marking of the lenticule area at its coordinates using an eye laser.

[0025] The eye laser can, for example, place a crosshair as a marker. Such a marker is not only minimally invasive but also easily verifiable.

[0026] According to a further preferred embodiment of the method according to the invention, the control device can determine the interfaces of a further lenticel to be extracted, preferably based on the result of a comparison between the determined target geometry and the observed actual geometry, wherein the lenticel to be extracted preferably contains only a reduction portion, and wherein the provided control data describe the interfaces of the further lenticel. Alternatively, the lenticel to be extracted can also be defined as the portion of the previously determined lenticel to be extracted. In other words, a portion of the determined lenticel to be rotated can be identified that is to be extracted before, during, or after the remaining portion is rotated.In the reduction portion, a piece of the lenticule can be removed, so that after rotation, the removed portion does not thicken the correction area elsewhere. This allows for the correction of an excessively thick area without excessively increasing the corneal thickness in other areas. This design enables even greater flexibility in refractive error correction. Furthermore, it creates more space for the rotation of the other lenticule or the remaining lenticule portion.

[0027] In further advantageous embodiments of the method according to the invention, the control device is configured such that the laser emits laser pulses in a wavelength range between 300 nanometers (nm) and 1400 nm, preferably between 700 nm and 1200 nm, with a pulse duration between 1 femtosecond (fs) and 1 nanosecond (ns), preferably between 10 fs and 10 picoseconds (ps), and a repetition frequency greater than 10 kilohertz (kHz), preferably between 100 kHz and 100 megahertz (MHz). Such lasers are already used for photodisruptive procedures in ophthalmic surgery. Such a femtosecond laser is particularly well suited for the production of volume bodies within the cornea. The use of photodisruptive lasers in the method according to the invention also has the advantage that the irradiation of the cornea does not have to take place in a wavelength range below 300 nm.In laser technology, this range is referred to as "deep ultraviolet." This advantageously prevents unintentional damage to the cornea caused by these very short-wavelength, high-energy beams. Photodisruptive lasers of the type used here typically deliver pulsed laser radiation with a pulse duration between 1 fs and 1 ns into the corneal tissue. This allows the power density of the respective laser pulse, necessary for optical breakthrough, to be spatially tightly limited, thus enabling high cutting accuracy in the creation of the interfaces. The wavelength range between 700 nm and 780 nm can also be selected.

[0028] Another aspect of the invention relates to a method for controlling a treatment device, wherein the method comprises the process steps of one of the embodiments of the method of the first aspect of the invention, as well as transmitting the provided control data to an ophthalmic surgical laser of the treatment device. The advantages already mentioned above are achieved.

[0029] A third aspect of the present invention relates to a control device configured to perform one of the methods described above. This results in the advantages listed above. The control device can, for example, be configured as a control chip, control unit, or user program ("app"). The control device can preferably include a processor and / or a data storage device. A processor is understood to be a device or device component for electronic data processing. The processor can, for example, include at least one microcontroller and / or at least one microprocessor. The optional data storage device can preferably contain program code for performing the method according to the invention.The program code can then be designed, when executed by the processor, to cause the control unit to carry out one of the embodiments of the inventive method described above.

[0030] A fourth aspect of the present invention relates to a treatment device comprising at least one ophthalmic surgical laser for the separation of a predefined corneal volume with predefined interfaces of a human or animal eye by means of photodisruption, and at least one control unit for the laser(s) configured to perform the steps of the method according to the first aspect of the invention, and / or the steps of the method according to the second aspect of the invention. The treatment device according to the invention makes it possible to reliably reduce or even avoid the disadvantages that occur when using conventional ablative treatment devices.

[0031] In a further advantageous embodiment of the treatment device according to the invention, the laser can be suitable for emitting laser pulses in a wavelength range between 300 nm and 1400 nm, preferably between 700 nm and 1200 nm, with a pulse duration between 1 fs and 1 ns, preferably between 10 fs and 10 ps, ​​and a repetition frequency greater than 10 kilohertz (kHz), preferably between 100 kHz and 100 megahertz (MHz). The advantages already mentioned above result.

[0032] In further advantageous embodiments of the treatment device according to the invention, 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. The aforementioned control data sets are typically generated based on a measured topography and / or pachymetry and / or morphology of the cornea to be treated and the type of refractive error to be corrected.

[0033] Further features and their advantages can be found in the descriptions of the first aspect of the invention, whereby advantageous embodiments of each aspect of the invention are to be regarded as advantageous embodiments of the other aspect of the invention.

[0034] A fifth aspect of the invention relates to a computer program comprising commands that cause the treatment device according to the fourth aspect of the invention to perform the process steps according to the first aspect of the invention and / or the process steps according to the second aspect of the invention.

[0035] A sixth aspect of the invention relates to a computer-readable medium on which the computer program according to the fifth aspect of the invention is stored. Further features and their advantages can be found in the descriptions of the first to fourth aspects of the invention, whereby advantageous embodiments of each aspect of the invention are to be regarded as advantageous embodiments of the other aspects of the invention.

[0036] Further features of the invention are evident from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as those subsequently mentioned in the description of the figures and / or shown in the figures alone, are not only usable in the combinations specified, but also in other combinations without departing from the scope of the invention. Thus, embodiments that are not explicitly shown and explained in the figures, but which can be derived and generated from the explained embodiments by separate combinations of features, are also to be considered as encompassed and disclosed by the invention. Embodiments and combinations of features that do not exhibit all the features of an originally formulated independent claim are also to be considered disclosed.Furthermore, embodiments and combinations of features, in particular those set out above, are to be considered disclosed which go beyond or deviate from the combinations of features set out in the cross-references of the claims. This shows. Fig. 1 a schematic representation of a treatment device according to the invention; Fig. 2 a schematic representation of the generation of a solid body to be rotated; Fig. 3 a schematic three-dimensional representation of a cornea with a keratoconus and a volume to be rotated; and Fig. 4 a schematic three-dimensional representation of a curved cornea and a solid body to be rotated.

[0037] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0038] The Fig. Figure 1 shows a schematic representation of a treatment device 10 with an ophthalmic surgical laser 18 for separating a predefined corneal volume, i.e., a lenticel 12 of the cornea 17 of a human or animal eye, which can also be referred to as a volume body, with predefined interfaces 14, 16 by means of photodisruption. It can be seen that a control unit 20 for the laser 18 can be provided next to the laser 18, so that it emits pulsed laser pulses into the cornea 17, for example, in a predefined pattern, whereby the determined interfaces 14, 16 of the lenticel 12 to be formed can be generated, for example, by a predefined pattern using photodisruption. Alternatively, the control unit 20 can be an external control unit 20 with respect to the treatment device 10.

[0039] In the illustrated embodiment, the determined interfaces 14, 16 form a lenticel 12, the position of which in this embodiment can be chosen such that it lies at least partially within a pathologically and / or unnaturally altered correction area 32 (see Fig. 2) lies, for example, within a stroma 36 of the cornea 17. Furthermore, it is from Fig. 1. It is evident that the so-called Bowman membrane 38 is formed between the stroma 36 and an epithelium 28. Alternatively to the one shown in the Fig. 1 and Fig. In the two examples shown, the lenticule 12 cannot be completely separated by the interfaces 14, 16. In other words, after laser ablation of the interfaces 14, 16, the lenticule 12 can remain connected to the rest of the cornea 17 in a rotational region.

[0040] Furthermore, the Fig. 1 and the Fig. 2, that the laser beam 24 generated by the laser 18 is deflected by means of a beam device 22, namely a beam deflection device, such as a rotary scanner, towards a surface 26 of the cornea. The beam deflection device is also controlled by the control device 20 in order to generate the determined interfaces 14, 16, preferably also a section 34 along a predetermined incision path or several sections 34 along predetermined incision paths.

[0041] The laser 18 shown is preferably a photodisruptive laser configured to emit laser pulses in a wavelength range between 300 nm and 1400 nm, preferably between 700 nm and 1200 nm, with a pulse duration between 1 fs and 1 ns, preferably between 10 fs and 10 ps, ​​and a repetition frequency greater than 10 kHz, preferably between 100 kHz and 100 MHz. The control device 20 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 in the cornea 17.The position data and / or focusing data of the individual laser pulses are generated, for example within the stroma 36 of the eye, based on a previously measured topography and / or pachymetry and / or the morphology of the cornea and the correction area 32 to be removed, pathological and / or unnaturally altered, or the optical refractive error correction to be produced, preferably based on a determined actual geometry of the cornea 17 of the correction area 32 and on an analysis of how the lenticule 12 should be designed to correct the refractive error.

[0042] The Fig. Figure 2 shows a schematic diagram of the generation of the lenticule 12 to be rotated according to an embodiment of the present method. It can be seen that the determined interfaces 14, 16 are generated by means of the pulsed laser beam 24, which is directed by the beam deflection device 22 towards the cornea 17 or towards the surface 26 of the cornea 17. The determined interfaces 14, 16 can form a lenticule 12 that lies at least partially within the pathological and / or unnaturally altered correction area 32. Furthermore, in the illustrated embodiment, the laser 18 generates a further cut 34 along an incision path that intersects the lenticule 12 at a predefined angle and with a predefined geometry and extends to the surface 26 of the cornea 17. The lenticle 12 defined by the interfaces 14, 16 can then be rotated out of the cornea 17 via the section 34.Optionally, part of lenticular 12 can be extracted.

[0043] In the illustrated embodiment, the pathological and / or unnaturally altered correction area 32 can, for example, be located within the stroma 36 and outside an optical axis 30 of an eye 40 ( Fig. 3) be trained.

[0044] In the illustrated embodiment, the interface 14, i.e., the interface located deeper in the eye 40 or the stroma 36, ​​can first be formed using the laser beam 24, with this then corresponding to the posterior interface 14. This can be achieved by guiding the laser beam 24 at least partially in a circular and / or spiral pattern. Subsequently, the interface 16 is generated in a comparable manner, which then corresponds to the anterior interface 16, so that the interfaces 14 and 16 form the lenticule 12 (see also Fig. 1) Form. Subsequently, section 34 is also created with laser 18. However, the sequence of creating interfaces 14, 16 and section 34 can also be changed.

[0045] The axis of rotation 31 for rotating D of the lenticel 12 can be predefined accordingly. After lasering the interfaces 14, 16, the rotation D by a predefined angle about the axis of rotation 31 can be carried out, for example, by one or more micro-forceps, which may be a component of the treatment device 10, or by means of other suitable instruments. The micro-forceps (not shown in the figures) can, for example, be controlled so that they are guided through the cut 34 or cuts 34 to reach the lenticel 12.

[0046] The procedure for providing the relevant tax data is explained in connection with the example of the Fig. 3 and the Fig. 4 explained in more detail. In the example of the Fig. 3. For example, the cornea 17 can develop a keratoconus. Such a keratoconus, i.e., a local thickening of the cornea 17, can form because the cornea 17 is so thin at this point that it bulges outwards due to the pressure of the eye's mass 40, i.e., the intraocular pressure. The area around the keratoconus can then, in the example of the Fig. 3 is defined or specified as the thickening component 42, i.e., as the portion of the correction area 32 that is to be thickened to correct the refractive error, in other words, its thickness is to be increased by the correction.

[0047] In the example of the Fig. Figure 3 also shows a reduction component 44, i.e., a portion of the correction area 32 that is too thick and is to be made thinner in the reduction component 44 to reduce astigmatism, i.e., its thickness is to be reduced.

[0048] To determine visual impairment data (procedure step S1, see below) Fig. 1) which, for example, can specify a value in diopters or other suitable data for describing the visual impairment, the control unit 20 can, for example, receive the corresponding data from a data server, or the visual impairment data can be determined as data input. The actual geometry of the correction area 32, i.e., a geometry of the correction area 32 before an intervention that causes the visual impairment, can be determined (S2) by, for example, measuring the correction area 32 using methods known to a person skilled in the art. Optionally, the determined visual impairment data can already describe the actual geometry.

[0049] Optionally, a three-dimensional, preferably digital, model of the cornea 17 and / or the correction area 32 can be provided based on the determined refractive error data and / or the determined actual geometry. For example, the target geometry of the correction area 32 can be determined using such a model (S3). The target geometry also describes, for example, the reduction component 44 and the thickening component 42. The target geometry fulfills a predefined refractive error reduction criterion, i.e., the requirement that the determined refractive error is reduced or even completely corrected by the target geometry. Optionally, the refractive error reduction criterion can, for example, specify a minimum value of such a reduction or a minimum probability with which the refractive error is reduced. The refractive error reduction criterion can, for example, be stored in the memory device.

[0050] Based on the determined actual geometry, preferably taking into account the determined target geometry, the control unit 20 can now determine the interfaces 14, 16 (S4). For this purpose, the control unit 20 can, for example, first calculate the shape of the lenticule 12. Optionally, the control unit 20 can first determine several possible positions and shapes of several lenticules 12 and predict a degree of refractive error reduction for each of the possible lenticules 12. The shape and / or position of a lenticule 12 that promises, for example, the highest degree of refractive error reduction can then be selected as a template for determining the interfaces 14, 16 (S4).

[0051] Due to the three-dimensional representation of the Fig. The anterior interface 14 and the posterior interface 16 are not shown in Figure 3. Fig. Figure 3, however, shows an exemplary outline of a lenticule 12, which, when rotated by, for example, 180 degrees around the axis of rotation 31, can shift the lenticule area, which according to the actual geometry lies at the reduction portion 44, to the location of the thickening area 42 and increase the corneal thickness there, so that the keratoconus can regress. The determined interfaces 14, 16 can either describe a lenticule 12 completely separated from the rest of the cornea 17, or, as in the example of the Fig. Figure 3 illustrates a lenticular 12 which is not separated from the rest of the cornea 17 in a rotation area 46.

[0052] The control unit 20 can specify the rotation angle and / or the axis of rotation 31 based on the result of a comparison between the determined actual geometry and the calculated target geometry, i.e., based on the corneal pathology. Alternatively or additionally, the control unit 20 can specify the rotation angle based on the determined refractive error data (S5). If the control unit 20 then provides the control data in process step S6, which, for example, describe the coordinates of the interfaces 14, 16, the control data can ideally also specify the rotation angle and / or the axis of rotation. The control data can also, for example, control an instrument for rotating the lenticule 12.

[0053] Preferably, the provided control data can also describe defined incision paths that specify the cut 34 or cuts 34 for the laser. For example, to define one or more incision paths (S7), it can be taken into account that these do not lie within the rotation range 46 ( Fig. 3).

[0054] If, for example, the analysis of the actual geometry shows that it is advantageous to remove a portion of the cornea 17 before, during, or after the identified lenticel 12 is rotated, then, for example, interfaces 14, 16 of another lenticel to be extracted can be identified (S4), which then form the portion to be removed, i.e., extracted, before, during, or after the rotation. Alternatively, and in other words, a lenticel region of the lenticel 12 to be rotated can be identified, and this identified lenticel region can then be removed for extraction before, during, or after the rotation in a manner known to those skilled in the art.

[0055] Extracting a lenticule area may be considered, for example, to reduce or even correct astigmatism, thereby flattening the cornea at the point where the lenticule area is extracted.

[0056] For operating the treatment device 10, in particular the treatment device 10 of the Fig. 1, the control unit 20 can then transmit the provided control data to the ophthalmic surgical laser 18 of the treatment device 10 (S8).

[0057] The Fig. Figure 4 shows an example where the cornea 17 may, for instance, exhibit an egg-shaped curvature. For example, a 90-degree rotation of a lenticule 12 can achieve half of the flattening, thus compensating for the curvature. The desired geometry with a flatter curvature is shown in the Fig. 4 is schematically represented as curvature 48. The curvature that, according to the actual geometry, creates the corneal pathology before the procedure is shown by lines 50.

[0058] Using the example of Fig. Figure 4 illustrates the optional marking of a lenticule area and / or an area of ​​the cornea 17 outside the lenticule 12 for the precise positioning of the lenticule 12. Such a marking or markings can also be optionally used in the example of Fig. 3. However, for the sake of clarity, this will only be described below for the sake of clarity. Fig. 4 described.

[0059] In the Fig. Figure 4 shows a highly simplified representation of the lenticule 12. For example, a 90-degree rotation D should result in a lenticule area 52 being positioned at a target end position after the rotation. This target end position can be determined (S9) by ascertaining the exact coordinates of the target end position on, for example, the aforementioned exemplary three-dimensional model of the correction area 32. The control unit 20 can determine the target end position and / or the lenticule area 52, in particular the coordinates of a reference point within the lenticule area 52. The provided control data can then specify that the eye laser 18 should place a mark at the coordinates of the point within the lenticule area 52 and / or at the target end position, for example, by lasering a line into the lenticule 12 and / or by lasering a line into, for example, the epithelium of the remaining corneal body 17.Preferably, for example, the marking applied to the epithelium of cornea 17, i.e., to the remaining body of cornea 17, can be a circle, and the marking 54 in the lenticule area 52 can then be, for example, a laser-etched cross. The rotation D can then be recognizably performed by the specified rotation angle if the marking 54 of the lenticule area 52 overlaps with the marking 54 in the epithelium. Optionally, both markings 54 can be laser-etched crosshairs.

[0060] In other words, a marker 54 can be physically placed on the lenticule 12. Additionally or alternatively, a marker 54 can be placed at the final target position. For example, if only one marker 54 is placed on the lenticule 12, the correction area 32 can be monitored during rotation D using a camera, and the final target position in the cornea 17 can be displayed graphically on a screen.

[0061] Overall, the examples illustrate how the invention enables and allows lenticular rotation to be performed.

[0062] According to a further embodiment, a method for a correction, in particular a special correction, preferably for a correction or corrections that are not rotationally symmetric, can be provided, wherein the lenticel 12 is cut in such a way that it does not need to be extracted, but is rotated about a center, i.e., about a rotation area 46 or a pivot point. A treatment device 10 can be used for this purpose: 1) to find the appropriate lenticule shape for a given rule of correction, i.e., the suitable shape needed for correction, for example, to correct the rule by rotation and not by extraction; and / or 2) Furthermore, the system can determine the extent of the rotation, i.e., specify the angle of rotation required to rotate the lenticular 12 so that the unrotated pattern is corrected; and / or 3) Furthermore, the system may be configured to perform such a cut 34 or such cuts 34 to generate this lenticular 12; and / or 4) Furthermore, the system may be configured to provide one or more markers 54 to facilitate rotation, particularly by a surgeon: a) a marker 54 on the corneal surface / in the epithelium as a target marker; this can, for example, be a cut to facilitate the rotation of the lenticule 12; and / or b) a further marking 54, preferably at the periphery of the lenticule surface as a rotational marking; and / or c) For example, a surgeon can overlay marking 54 on lenticule 12 with marking 54 on the epithelium; this results in an exact rotation and thus the correction.

[0063] According to a further, particularly preferred embodiment, the system, in particular the treatment device 10, can leave a central area, for example the rotation area 46, "uncut" so that it serves as a pivot point. Preferably, the system, in particular the treatment device 10, can include means for determining whether a rotation of the lenticel 12 is sufficient, or whether a combination approach should be followed in which two lenticels 12 or two lenticel components are connected and / or determined (preferably both smaller than a conventional lenticel 12), with one being rotatable and the other being extracted.

[0064] The following describes preferred embodiments with precise dimensions and exemplary visual impairment data.

[0065] In the first example, the strength of the refraction can be + 3.5 - 7.0 Dx 0 (medical notation of the strength of the refraction: SCA, i.e. sphere, cylinder, axis).

[0066] A cylinder (toric lens, "C") describes a "relative" curvature, while a sphere (spherical lens, "S") describes an absolute curvature. The absolute curvatures are therefore S in the A-axis position; S+C in the axis perpendicular to the A-axis position; and the intermediate value is S+C / 2*(1-cos(2*(axis-A))).

[0067] In this example, the strength of the refraction could be: a sphere of +3.5D, a cylinder or cylindrical shape of -7.0D, and a rotation axis ("A") of the cylinder of 0deg, i.e. 0 degrees.

[0068] In this example, the refractive power can also be described as -3.5 + 7 x 90; it has the same effect. In other words, at 0 degrees the power can be +3.5D (at 90 degrees +3.5 - 7 = -3.5D).

[0069] In this example, something can be determined to compensate, for example, a central lenticule 12 that has a strength of +3.5D at 0 degrees and zero strength at 90 degrees. This can be, in particular, 0 + 3.5 × 90, i.e., S = 0D, C = +3.5D, A = 90 degrees (0D strength at 90 degrees, and 0 + 3.5 = +3.5D strength at 0 degrees). If this is rotated by 90 degrees, then it acts as 0 + 3.5 × 0. If the is "inserted" instead of removed, then it acts as 0 - 3.5 × 0 (S = 0D; C = -3.5D; A = 0 degrees (0D strength at 0 degrees, and 0 - 3.5 = -3.5D strength at 90 degrees)).

[0070] The combination results in a strength of +3.5D+OD=+3.5D at 0 degrees and 0-3.5=-3.5D at 90 degrees, i.e., as desired +3.5-7×0.

[0071] Alternatively, with a strength of +3.5 - 7 = -3.5D at 90 degrees and zero strength at 0 degrees, this would be 0 - 3.5 × 0 (S = 0D; C = -3.5D; A = 0°, meaning 0D strength at 0 degrees and 0 - 3.5 = -3.5D strength at 90 degrees). Rotating this by 90 degrees results in 0 - 3.5 × 90. Adding to this, instead of removing, results in 0 + 3.5 × 90 (S = 0D; C = +3.5D; A = 90°, meaning 0D strength at 90 degrees and 0 + 3.5 = +3.5D strength at 0 degrees). Therefore, this combination results in +3.5D + 0D = +3.5D strength at 0 degrees and 0 - 3.5 = -3.5D strength at 90 degrees, as desired. +3.5-7x0.

[0072] This example for +3.5-7.0Dx0 can be summarized as follows: 1) The system can either perform a 0+3.5Dx90 rotation by 90 degrees, 2) or a 0-3.5Dx0 to rotate 90 degrees, 3) The +3.5-7.0Dx0 in 7mm (millimeters) has a central diameter of 65µm (micrometers), a maximum depth of 135µm, and a volume of 3700nl ​​(nanoliters). 1) The 0+3.5Dx90 in 7mm takes up 0µm centrally (-100%), 65µm maximum depth (-50%), and 1400nl volume (-60%) 2) The 0-3.5Dx0 in 7mm occupies 65µm centrally (-0%), 65µm maximum depth (-50%), and 2300nl volume (-40%) 3) No tissue is extracted

[0073] In another example with a refractive power of +2.0 - 6.0 Dx0, the following can be done analogously: 1) the system either performs a 0+3.0D×90 rotation by 90 degrees, 2) or rotate a 0-3,0D×0 by 90 degrees, 3) plus a -1.00 sphere to be extracted, 4) The +3.0-6.0D×0 in 7mm occupies 55µm centrally, 115µm maximum depth, and 3100nl volume 1) The 0+3.0D×90 in 7mm has a central thickness of 0µm, a maximum depth of 55µm, and a volume of 1200nl. 2) The 0-3.0D×0 in 7mm occupies 55µm centrally, 55µm maximum depth, and 1900nl volume. 3) The -1.00 in 7mm occupies 15µm centrally (-70%), 15µm maximum depth (-85%), and 350nl volume (-85%). Only this can then be extracted.

[0074] In another example of the treatment of keratoconus (compare, for example, Fig. 3) The system, in particular the treatment device 10, can preferably be controlled such that it performs a treatment on, for example, half of the coma, which is to be rotated by, for example, 180 degrees. Preferably, the system, in particular the treatment device 10, can apply markings 54 to the lenticule 12 and / or to, for example, the epithelia, which are, for example, 180 degrees opposite each other.

[0075] According to a further embodiment, control data for the generic treatment of keratoconus can be provided. The system, in particular the treatment device 10, can be controlled such that it performs treatment on half of the coma, which, for example, is to be rotated by 180 degrees. Markers 54 can be placed, for example, 180 degrees apart or opposite each other, preferably on the lenticule 12 and in the epithelium. In addition, a myopic sphere can be extracted, preferably a small myopic sphere.

[0076] According to a further embodiment, the treatment device 10 can be used to treat a cloverleaf-shaped corneal abrasion 17 through the eyelid ("trefoil"). The system, in particular the treatment device 10, can be controlled such that it treats either half of the "cloverleaf" (i.e., areas to be corrected that are at an angle of approximately 120 degrees to each other) while rotating by 60 degrees. Additionally, markings 54 can be applied at an angle of 60 degrees to each other in the lenticule 12 and epithelia.

[0077] According to a further embodiment, a generic treatment of such a cloverleaf structure can be carried out. The system, in particular the treatment device 10, can, for example, process half of the "cloverleaf," which is preferably to be rotated by 60 degrees. Markings 54, positioned at an angle of 60 degrees to each other, can be applied to the lenticel 12 and epithelium. Preferably, a sphere can also be extracted, i.e., a lenticel region, in particular a small lenticel region.

Claims

[1] Method for providing control data for an ophthalmic surgical laser, the method comprising the following steps performed by a control device (20): - Determining refractive error data describing a degree of refractive error of a human or animal eye (40) (S1), - Determining an actual geometry of a correction area (32) of a cornea (17) of the eye (40), which describes three-dimensional dimensions of the correction area (32) of the cornea (17) (S2), - based on the determined refractive error data and the determined actual geometry: Determining a target geometry of the correction area (32) that describes a reduction component (44) of the correction area (32) with a corneal thickness reduced compared to the actual geometry, and / or a thickening component (42) with a corneal thickness increased compared to the actual geometry; wherein the determined target geometry fulfills a predefined refractive error reduction criterion that specifies suitability for reducing the degree of refractive error (S3), - Specifying the angle of rotation and the axis of rotation (31) depending on: a) a result of a comparison of the determined actual geometry with the determined target geometry, and / or b) the determined visual impairment data (S5), - based on the determined actual geometry: Determining interfaces (14, 16) of a lenticel (12) within the correction area (32), which extends at least partially over the correction area (32), wherein a portion of the lenticel (12) is designed such that, when the lenticel (12) is rotated (D) into the thickening portion (42) about the specified axis of rotation (31) passing through the cornea (17) and about the specified angle of rotation, it transforms the correction area (32) from the determined actual geometry into the determined target geometry (S4), - Defining at least one incision path as access for an instrument to rotate the lenticule (12), which extends from a predetermined incision site on an outer surface of the cornea (17) to one of the defined interfaces (14, 16) (S7), and - Providing control data that describe the determined interfaces (14, 16) for forming the lenticel (12), the at least one determined incision path, the specified axis of rotation (31) and a rotation of the lenticel (12) about the specified angle of rotation (S6). [2] Method according to any one of the preceding claims, characterized by , that the control device (20) determines a target end position of a predetermined lenticular area (52) of the rotated lenticular (12) (S9), and wherein: - the provided control data describe a marking of the determined target end position outside the lenticular (12); and / or wherein - the provided control data describe a marking of the specified lenticular area (52). [3] Method according to claim 2, characterized by , that the provided control data describes marking the lenticule area (52) at its coordinates by an eye laser. [4] Method according to any one of the preceding claims, characterized by , that the interfaces (14, 16) completely separate the lenticule (12) from the cornea (17). [5] Method according to any one of claims 1 to 3, characterized by , that the determined interfaces (14, 16) separate the lenticule (12) from the correction area (32) of the cornea (17) only outside a rotation area (46) of the lenticule (12) through which the specified axis of rotation passes, so that the lenticule (12) remains connected to the body of the cornea (17) connected to the dermis in the rotation area (46). [6] Method according to any one of the preceding claims, characterized by , that the control unit (20) performs: - Determining interfaces (14, 16) of a further lenticel (12) to be extracted or of a lenticel area (52) to be extracted of the lenticel (12) to be rotated based on a result of a comparison of the determined target geometry and the determined actual geometry, which is preferably only located in the reduction portion (44); wherein the provided control data describe the interfaces (14, 16) of the further lenticel (12) or of the lenticel area (52) to be extracted (S4). [7] Method according to any one of the preceding claims, characterized by , that the control device (20) is designed such that the laser (18) emits laser pulses in a wavelength range between 300 nm and 1400 nm, preferably between 700 nm and 1200 nm, with a respective pulse duration between 1 fs and 1 ns, preferably between 10 fs and 10 ps, ​​and a repetition frequency greater than 10 kHz, preferably between 100 kHz and 100 MHz. [8] Method for controlling a treatment device (10), wherein the method comprises: - the process steps of a process according to one of the preceding claims, and - Transferring the provided control data to an ophthalmic surgical laser (18) of the treatment device (10, S8). [9] Control device (20) configured to perform a procedure according to any of the preceding claims. [10] Treatment device (10) comprising at least one ophthalmic surgical laser (18) for the separation of a corneal volume with predefined interfaces (14, 16) of a human or animal eye (40) by means of photodisruption and at least one control device (20) according to claim 9. [11] Treatment device (10) according to claim 10, characterized by, that the laser (18) is suitable for emitting laser pulses in a wavelength range between 300 nm and 1400 nm, preferably between 700 nm and 1200 nm, with a respective pulse duration between 1 fs and 1 ns, preferably between 10 fs and 10 ps, ​​and a repetition frequency greater than 10 kHz, preferably between 100 kHz and 100 MHz. [12] Treatment device (10) according to claim 10 or 11, characterized by , that the control device (20): - has 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 - comprises at least one beam device (22) for beam guidance and / or beam shaping and / or beam deflection and / or beam focusing of a laser beam (24) of the laser (18). [13] Computer program comprising instructions that cause the treatment device (10) according to one of claims 10 to 12 to perform a method according to one of claims 1 to 7 and / or a method according to claim 8. [14] Computer-readable medium on which the computer program according to claim 13 is stored.

Images