Methods for providing control data for an ophthalmic surgical laser and methods for controlling a treatment device

Abstract

Method for providing control data for an ophthalmic surgical laser (18), wherein the method comprises the following steps performed by a control device (20): - Determining refractive error data for at least one eye-specific parameter describing a refractive error and / or a geometry causing the refractive error of a human or animal eye (36) (S1), - based on the determined refractive error data: Determining a lenticule geometry that describes the dimensions of a lenticule (12) and its position (S2), - Defining a posterior interface (14) of the lenticel (12) and an anterior interface (16) of the lenticel (12) as intersection surfaces to form the lenticel (12, S3), - Defining at least two differently positioned incision paths (46, 48), each extending from a predetermined incision site on an outer surface of the cornea (17) to one of the defined interfaces (14, 16) (S4); wherein the predetermined incision sites are at a predetermined angle to each other about a predetermined reference point, and wherein only one of the incision paths (46, 48) extends only to the defined anterior interface (16) within a lenticule rim (40) where the defined anterior (16) and the defined posterior interface (14) meet; wherein the further incision path (48) lies outside the lenticule rim (40) and within the larger of the two interfaces (14, 16), and - Providing control data for controlling the ophthalmic surgical laser (18) which describe the at least two specified incision paths (46, 48) and the specified interfaces (14, 16) (S7).

Description

[0001] The present invention relates to a method for providing control data for an ophthalmic surgical laser. The ophthalmic surgical laser can be controlled to detach a corneal volume with predefined interfaces, this corneal volume being hereinafter referred to as a lenticule. The invention further relates to a method for controlling a treatment device with an ophthalmic surgical laser, a control device for carrying out the respective method, 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. Small-incision lenticular extraction (SMILE), a method of refractory surgery in which a corneal lenticule is removed through a peripheral incision, can be performed as a laser for laser-assisted in situ keratomileusis (LASIK). 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. Femtosecond systems are used in corneal surgery to perform, for example, deep anterior lamellar keratoplasty (DALK) and / or penetrating keratoplasty (PKP).

[0003] Lenticel extraction is performed through an incision, preferably a small one. This ensures that both interfaces, i.e., both cutting planes, are accessed.

[0004] Currently, it is difficult to locate these interfaces, or, once located, to determine whether the dissection or sectioning should take place at the anterior or posterior end, i.e., at an anterior or posterior interface of the lenticule—that is, at the upper or lower incision. The current technique involves making a single incision where the upper and lower incision planes meet, i.e., where the anterior and posterior interfaces meet, in order to then section the interfaces and extract the lenticule. This entails repeatedly searching for and inserting an instrument into the same incision, which can cause corneal swelling.

[0005] US 2015 / 0057644 A1 relates to a method for refractive correction comprising controlling a focus of pulsed laser radiation with ultrashort pulses by one or more laser components.

[0006] One of the problems underlying the invention is to shorten the operative manipulation for cutting the interfaces and / or extracting the lenticel.

[0007] The problem is solved by the inventive method and the inventive devices according to the dependent claims. Advantageous embodiments are given by the sub-claims.

[0008] Instead of performing only a single incision and reusing it multiple times, as is done in the prior art, the invention is based on the idea of ​​providing at least two different incision paths, so that differently positioned incisions are used when multiple incisions are made. Each of the incision paths, i.e., each of the predetermined incision routes along which the incision is made to a designated interface, extends from a predetermined incision point on an outer surface of the cornea to one of the defined interfaces. The predetermined incision points (and thus the incision paths) are therefore at a predetermined angle to each other about a predetermined reference point. Only one of the incision paths leads to a defined anterior interface.

[0009] This allows for more precise guidance when cutting the interfaces. Surgical manipulation is significantly shortened and is less invasive than prior art methods. For example, the invention can reduce surgical manipulation to only six to seven seconds.

[0010] 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.

[0011] The control unit determines refractive error data for at least one eye-specific parameter, describing a refractive error and / or the geometry of a human or animal eye that causes the refractive error. This refractive error data can, for example, describe ametropia, i.e., a deviation of the refractive power of an eyeball from the ideal value, such as myopia, hyperopia, or astigmatism. The refractive error data can, for example, describe a refractive power value, i.e., a value in diopters, or, for example, a deviation of astigmatism 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.

[0012] Based on the determined refractive error data, the control unit calculates a lenticule geometry, which describes the dimensions of a lenticule and its position in the cornea. In other words, the calculated lenticule geometry describes the desired shape of the lenticule and its position in the cornea. The lenticule could then, for example, be one that is to be extracted after cutting.

[0013] The control mechanism defines a posterior and anterior interface of the lenticule as the surfaces used to form or shape the lenticule. A lenticule is understood to be a solid body of the cornea, for example, a disc-shaped disk. The interfaces can form, for example, a biconvex, biconcave, plano-convex, or plano-concave solid body. The lenticule or solid body can optionally be lens-shaped or, alternatively, bean-shaped. The lenticule can be symmetrical or asymmetrical.

[0014] The control unit defines at least two differently positioned incision paths, each extending from a predetermined incision point on the outer surface of the cornea to one of the defined interfaces. The predetermined incision points are positioned at a predetermined angle to each other around a predetermined reference point, with only the first of the incision paths extending to the defined anterior interface within a lenticule rim. The lenticule rim is the area of ​​the lenticule where the defined anterior and posterior interfaces meet. Thus, the defined incision paths determine the trajectory of a cut that the ophthalmic surgical laser is to perform.

[0015] The incision continues outside the lenticule margin and within the larger of the two interfaces. The advantage of this approach is that only one area is stressed, allowing it to be "covered" by the eyelid, for example, thus minimizing visual disturbances. The stressed area can then be positioned "superior," meaning it extends 90° upwards from the optical axis.

[0016] The control unit provides control data for the ophthalmic surgical laser, describing at least two defined incision paths and defined interfaces. The control unit can generate this control data, for example. This data can describe, for instance, the coordinates of the interfaces and the incision paths, and / or vectors along which the laser is to cut the interfaces and / or the incision.

[0017] The aforementioned advantages result.

[0018] Preferably, the first incision extends towards an optical zone region of the defined anterior interface, i.e., the region adjacent to a transition zone located between the optical zone region and the lenticule margin. The optical zone is the region where the correction is to be performed. The transition zone is therefore the region between the optical zone region and the lenticule margin. The transition zone is a progressive transition where the correction can be performed. The transition zone is a progressive transition where the correction approaches zero. An incision towards the transition zone provides excellent access to the lenticule.

[0019] Alternatively, the first incision line can extend to the transition area of ​​the defined anterior interface, which lies between the optical zone of the lenticule and the lenticule margin.

[0020] According to a further embodiment of the method according to the invention, the incision path extending only towards the defined anterior interface (i.e., the first incision path) can run straight between its incision point and the defined anterior interface. Alternatively, the incision path can be curved.

[0021] In another example, the first incision path can run within the largest of the two interfaces, and the subsequent incision path can meet the posterior interface in the optical zone region.

[0022] One embodiment of the method according to the invention provides that the first incision path and the subsequent incision path, in particular a further incision path, run in the same axial orientation relative to each other, preferably wherein the incision point of the first incision path has a different distance to the optical axis than the incision point of the subsequent incision path. Here, too, the advantage arises that only one point is stressed (typically superior, i.e., preferably 90° upwards), so that, for example, it is "covered" by the eyelid and few visual problems could arise.

[0023] Optionally, the incision point of the first incision line, extending towards the anterior interface, can be located closer to the optical axis than the incision point of the subsequent incision line. In an advantageous embodiment, the first incision line can extend towards the transition zone of the defined anterior interface.

[0024] According to a further embodiment of the method according to the invention, the control unit can define a number of incision paths based on the determined refractive error data. According to a further development, the control unit can define three or more differently positioned incision paths. This allows for individualized treatment of any detected corneal pathology.

[0025] This advantage also arises if the control device specifies the incision points by setting the angle based on the determined refractive error data, whereby the specified angle can preferably be 0°, 60°, 90°, 120° or 180°. Ideally, the incision lines can be at an angle of 0°, 60°, 90°, 120° or 180° to each other.

[0026] In advanced training, the control unit can specify three incision sites, each with a 60° angle between them. Alternatively, the control unit can specify two incision sites and a 180° angle if the refractive error data describes astigmatism with a refractive error of at least two diopters. This is a particularly individualized and precise setting for treating astigmatism with a refractive error of at least two diopters.

[0027] According to a further embodiment of the method according to the invention, the determined at least one eye-specific parameter can be a parameter of an actual corneal geometry, in particular a thickness of a portion of the cornea (i.e., a corneal thickness), and / or a corneal curvature. The method can include defining a target corneal geometry by the control device, and the lenticule geometry can be determined based on the defined target geometry.

[0028] Ideally, the provided control data can also describe the defined boundary surfaces.

[0029] 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 a femtosecond laser is particularly well suited for the production of volume structures 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. This range is referred to in laser technology as "deep ultraviolet".This advantageously prevents unintentional damage to the cornea caused by these very short-wavelength and 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 generation of the interfaces. The wavelength range between 700 nm and 780 nm can also be selected.

[0030] 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 result.

[0031] 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 carrying out 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 one or both of the methods of the invention described above.

[0032] 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 device 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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 representation of an eye in a coordinate system for a further embodiment of the method according to the invention; and Fig. 4 a schematic representation of an eye in a coordinate system for a further embodiment of the method according to the invention.

[0039] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0040] 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 17 of a human or animal eye 36, i.e., a lenticel 12, 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 alongside 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.

[0041] The identified interfaces 14, 16 form a lenticel 12 in the illustrated embodiment, the position of which is chosen such that it can, for example, lie within a stroma 32 of the cornea 17. Furthermore, it is Fig. 1. It can be seen that the so-called Bowman membrane 34 may be formed between the stroma 32 and an epithelium 28.

[0042] 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 incisions or cuts 30, along predetermined incision paths 46, 48.

[0043] 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 based on a previously measured topography and / or pachymetry and / or the morphology of the cornea or the optical refractive error correction to be produced, for example within the stroma 32 of the eye 36, preferably based on a determined actual geometry of the cornea 17 and based on an analysis of how the lenticule 12 should be designed to correct the refractive error.

[0044] The Fig. Figure 2 shows a schematic diagram of the generation of the lenticel 12 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 lenticel 12. Furthermore, in the illustrated embodiment, the laser 18 generates additional cuts 30, each along an incision path 46, 48, which intersects the lenticel 12 at a predefined angle and with a predefined geometry, extending to the surface 26 of the cornea 17. The lenticel 12, defined by the interfaces 14, 16, can then be extracted from the cornea 17 via the respective cut 30.

[0045] 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 refractive error, the control unit 20 can, for example, receive the corresponding data from a data server, or the refractive error data can be determined as data input. Optionally, the actual geometry of an area to be corrected, i.e., the geometry of the area before an intervention that causes the refractive error, can be determined, for example, by measuring the area to be corrected using methods known to a person skilled in the art. Optionally, the determined refractive error data can already describe the actual geometry. The actual geometry can, for example, be the thickness of a portion of the cornea 17, and / or the curvature of the cornea 17.

[0046] Optionally, a three-dimensional, preferably digital, model of cornea 17 and / or the area to be corrected can be generated based on the determined refractive error data and / or the optionally determined current geometry. For example, a target geometry of the area to be corrected can be determined using such a model. The target geometry can optionally fulfill a predefined refractive error reduction criterion, i.e., the requirement that the determined refractive error is reduced or even completely eliminated by the target geometry. Optionally, the refractive error reduction criterion can, for example, specify a minimum value for such a reduction or a minimum probability with which the refractive error will be reduced. The refractive error reduction criterion can, for example, be stored in the memory device.

[0047] For example, if there is a refractive error of five diopters, a correction can be provided by, for example, the removal of a lenticule 12 at a depth of six millimeters in the optical zone 42.

[0048] A first incision path 46 can generally intersect the anterior interface 16 anywhere along it and then proceed directly, or in a broken or curved manner, outwards to the surface 26 of the cornea 17. This can then serve to separate the section along the anterior interface 16. A further incision path 48 can preferably only run outside the transition region 38 and outside the lenticule margin 40, and can then intersect the posterior interface 14 directly or in a curved (or broken, but not interrupted) manner at the end of the transition region 38. This can then serve to separate the section along the transition region 38 and / or the lenticule margin 40. However, both incision paths 46, 48 do not act at the same location, i.e., they do not overlap, because otherwise they would effectively be only one incision path 44.

[0049] The Fig. 3 and the Fig. Figure 4 each shows a coordinate system in which a cross-sectional cross-section of an eye is schematically drawn. The abscissa x shows a radial distance in mm, and the ordinate y shows the so-called "z value", i.e., the depth in the eye tissue, in micrometers.

[0050] For the sake of clarity, eye 36 is shown schematically without a lens, so that the Fig. 3 and the Fig. 4. Highlight the eye coordinates of cornea 17.

[0051] In process step S2, the control unit 20 determines a lenticule geometry, i.e., the dimensions of the lenticule 12 to be extracted, for example, and preferably also its position. This also defines the posterior interface 14 and the anterior interface 16 of the lenticule 12 (S3), i.e., the cross-sectional surfaces for forming the lenticule 12. Section depths at different positions can also be determined, for example.

[0052] The Fig. Figure 3 illustrates the location of the transition zone 38, which lies between a lenticule edge 40, where the two interfaces 14 and 16 meet, and an optical zone 42. The optical zone 42 can also be referred to as the optical zone region. Fig. Figure 3 shows, to better illustrate the difference between the invention and the prior art, an incision path 44 which would be the only incision path 44 that would be performed according to the prior art. In other words, the only incision path 44 shows where, according to the prior art, a cut 30 would be made to form and extract the lenticule 12. In the example of the Fig. 3. Instead of a single cut along incision path 44, the control device 20 would define, for example, a first incision path 46 (S4) and a second incision path 48. In other words, incision paths 46 and 48 replace the previously used incision path 44. The respective incision paths 46, 48 begin at a corresponding incision site on the surface 26 of the cornea 17.

[0053] In the example of the Fig. 3. The first incision path 46, i.e., the one extending solely towards the anterior interface 16, extends towards the anterior interface 16 such that the incision path 46 meets the anterior interface 16 in the transition region 38. The second incision path 48 can preferably be, as shown in the Fig. Figure 3 shows the incision extending outside the lenticule margin 40 and meeting the posterior interface 14 at the lenticule margin 40. The length of an incision 46, 48 can be, for example, two millimeters, or in a length range between 1.5 and 2.5 mm.

[0054] In the example of the Fig. 3. The first incision line 46 can initially be straight and then curved. Alternatively, the first incision line 46 can be completely straight. The Fig. Figure 4 shows an example where the first incision line 46 meets the anterior interface 16 in the transition region 38 and can, for example, run straight. The first incision line 46 can, for example, meet the anterior interface 16 at a boundary between the transition region 38 and the optical zone 42. The subsequent incision line 48 can preferably meet the posterior interface 14 at the lenticule margin 40, i.e., at the outer end of the transition region 38.

[0055] Depending on the geometry, the control unit 20 can specify the number of incision paths 46, 48 (S5), for example two, as in the examples of the Fig. 3 and the Fig. 4, or more, for example, three. Optionally, the control unit 20 can also define and thus specify the angle (S6) by determining the relative positions of the incision points and / or the incision paths 46, 48. If, for example, the refractive error data describes a refractive error of three diopters, two incision paths 46, 48 can be defined (S5) that are at an angle of 180° to each other, or whose incision points are offset by 180° around a reference point, for example, an intersection of the optical axis of the eye 36 with the surface 26 of the cornea 17.

[0056] For example, two incision paths 46, 48 can be defined (S4, S5) so that two cuts 30 are made during the actual treatment, each of the incision paths 46, 48 being assigned to one of the cut surfaces, i.e., interfaces 14, 16. The first incision path 46—and thus a first cut 30—can extend to the lenticule margin 40, but preferably to the transition region 38 of the lenticule, and provide access to the upper cut surface, i.e., to the anterior interface 16. Preferably, if a transition region 38 is present or provided, this incision path 46 can extend within the transition region 38, i.e., within the lenticule 12, but outside the optical zone 42.The second incision path 48 for a second cut 30 can run along the lenticule edge 40 of the lenticule 12, preferably run outside the lenticule edge 40 and meet it from outside the lenticule edge 40, and provide access to the lower cut surface, i.e. to the posterior interface 14.

[0057] Both incision trajectories 46 and 48 can be positioned depending on the individual pathology. In one case, for example, a 180° rotation might induce astigmatism, i.e., corneal curvature and thus a refractive error. In another case, however, such an orientation can be used to correct astigmatism and exclude it from lenticule refraction. This depends on the individual corneal pathology.

[0058] To correct astigmatism, the incision lines 46, 48 can preferably induce a coma when offset by 90°, a cloverleaf structure when offset by 60°, and a four-leaf clover structure when offset by 45°. The 45° and 60° configurations can be considered the most refractively neutral.

[0059] In other words, a 180° offset can exacerbate curvature, while in other individual cases it may be suitable for correcting refractive errors. The angle therefore depends on the individual pathology. A 90° offset may be preferred.

[0060] The control data describing the coordinates of the defined interfaces 14, 16 and the at least two defined incision paths 46, 48 are provided by the control unit 20 (S7) and can optionally be transmitted to the ophthalmic surgical laser 18 of the treatment device 10 (S8).

[0061] Overall, the examples illustrate how a procedure can be made possible by multiple incisions.

[0062] Preferably, both incision paths 46, 48 can lie in the same axial position, but with different radii, preferably a narrower radius for the incision path 46 as access to the anterior interface 16, and a wider radius for the incision path 48 to the lenticule margin 40 and / or transition region 38. Preferably, both incision paths 46, 48 can have different angles.

[0063] According to another preferred example, the incision 46, providing access to the anterior interface 16, can have a narrower radius and may lie within the transition region 38 and / or the lenticule margin 40. The subsequent incision 48, providing access to the transition region 38, can then have a wider radius and lie outside the transition region 38 and / or the lenticule margin 40.

[0064] According to another preferred example, the first incision 46, providing access to the anterior interface 16, may have a narrower radius and lie within the perimeter of the transition region 38. The subsequent incision 48, providing access to the transition region 38, may have a wider radius and lie outside the perimeter of the transition region 38 and / or the lenticule margin 40.

[0065] According to another example, both incision paths 46, 48 can have the same axis orientation; for example, both can run horizontally at 0° or both diagonally at 30°. With the same axis orientation, the incision paths 46, 48 can then preferably have different distances from a center point.

[0066] According to another example, at the same distance from the center, both incision paths 46, 48 have different axes, meaning, for example, that both incision paths 46, 48 at, for example, 4 mm, can have one axes at, for example, 0° and the other at 90°.

[0067] The advantage of having the same axis but different radii is that only one point is stressed, typically superior, i.e., for example 90° upwards, so that it is covered by the eyelid and causes fewer visual problems.

[0068] With differing axis orientations, regardless of whether they have the same or different radii, the angle is not absolute with respect to a static reference axis, but rather "relative to each other" of the multiple incision paths 46, 48, i.e., a difference in the angle between the incision paths 46, 48. A difference of 0 therefore means that both incision paths 46, 48 lie on the same axis orientation. Differences of, for example, 60° or 120° can induce astigmatism, coma, or a three-leaf clover structure. A difference of 90°, if astigmatism is induced, can only induce coma and is therefore a preferred embodiment. A difference of 180° would only induce astigmatism, but not coma or a three-leaf clover structure.

[0069] According to a further preferred embodiment, one of the incision paths can meet the interfaces 14, 16 precisely at the lenticule edge 40. According to a further preferred embodiment, one of the incision paths 46, 48 can meet the respective interface 14, 16 at a boundary between the optical zone 42 and the transition zone, i.e., the transition region 38.

Claims

[1] Method for providing control data for an ophthalmic surgical laser (18) wherein the method comprises the following steps performed by a control device (20): - Determining refractive error data for at least one eye-specific parameter describing a refractive error and / or a geometry causing the refractive error of a human or animal eye (36) (S1), - based on the determined refractive error data: Determining a lenticule geometry that describes the dimensions of a lenticule (12) and its position (S2), - Defining a posterior interface (14) of the lenticel (12) and an anterior interface (16) of the lenticel (12) as intersection surfaces to form the lenticel (12, S3), - Defining at least two differently positioned incision paths (46, 48), each extending from a predetermined incision site on an outer surface of the cornea (17) to one of the defined interfaces (14, 16) (S4); wherein the predetermined incision sites are at a predetermined angle to each other about a predetermined reference point, and wherein only one of the incision paths (46, 48) extends only to the defined anterior interface (16) within a lenticule rim (40) where the defined anterior (16) and the defined posterior interface (14) meet; wherein the further incision path (48) lies outside the lenticule rim (40) and within the larger of the two interfaces (14, 16), and - Providing control data for controlling the ophthalmic surgical laser (18) which describe the at least two specified incision paths (46, 48) and the specified interfaces (14, 16) (S7). [2] Method according to claim 1, characterized by , that the first incision line (46) extends to an optical zone (42) of the defined anterior interface (16), which is adjacent to a transition area (38) that lies between the optical zone (42) and the lenticule margin (40). [3] Method according to claim 1, characterized by , that the first incision line (46) extends to the transition area (38) of the defined anterior boundary (16), which lies between an optical zone (42) of the lenticule (12) and the lenticule margin (40). [4] Method according to any one of the preceding claims, characterized by, that the incision line (46) extending only to the defined anterior boundary (16) runs straight between its incision point and the defined anterior boundary (16). [5] Method according to any one of the preceding claims, characterized by , that the first incision path (46) and the further incision path (48) run in the same axial position relative to each other; preferably wherein the incision point of the first incision path (46) has a different distance to the optical axis than the incision point of the further incision path (48). [6] Method according to any one of the preceding claims, characterized by , that the incision point of the first incision path (46), which extends to the anterior interface (16), is a shorter distance from the optical axis than the incision point of the further incision path (48). [7] Method according to claim 6, characterized by, that the first incision line (46) extends towards the transition area (38) of the defined anterior boundary surface (16). [8] Method according to any one of the preceding claims, characterized by , that the control unit (20) performs: Determining a number of incision trajectories (46, 48) based on the identified refractive error data (S5). [9] Method according to claim 8, characterized by , that the control device (20) specifies three or more differently positioned incision paths (46, 48) (S5). [10] Method according to any one of the preceding claims, characterized by , that the control unit (20) performs: Specifying the incision points by determining the angle based on the determined refractive error data (S6), preferably wherein the specified angle is an angle of 0°, 60°, 90°, 120° or 180°; in particular wherein the incision lines (46, 48) are at an angle of 0°, 60°, 90°, 120° or 180° to each other. [11] Method according to claim 10, characterized by , that the control device (20) specifies three incision points (S5) and sets an angle of 60° between the incision points (S6). [12] Method according to claim 10, characterized by , that the control device (20) specifies two incision sites (S5) and sets an angle of 180° (S6) if the refractive error data describe astigmatism with a refractive error of the eye (36) of at least two diopters. [13] Method according to any one of the preceding claims, characterized by, that the identified at least one eye-specific parameter is a parameter of an actual geometry of the cornea (17), in particular: - a thickness of a portion of the cornea (17), and / or - a curvature of the cornea (17); wherein the method comprises defining a target geometry of the cornea (17) by means of the control device (20), and wherein the lenticule geometry is determined based on the defined target geometry. [14] Method according to any one of the preceding claims, characterized by , that the provided control data additionally describe the defined boundary surfaces (14, 16). [15] 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. [16] 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). [17] Control device (20) configured to carry out a procedure according to any of the preceding claims. [18] Treatment device (10) with at least one ophthalmic surgical laser (18) for separating a corneal volume with predefined interfaces (14, 16) of a human or animal eye (36) by means of photodisruption and at least one control device (20) according to claim 17. [19] Treatment device (10) according to claim 18, 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. [20] Treatment device (10) according to claim 18 or 19, 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). [21] Computer program comprising commands that cause the treatment device (10) according to one of claims 18 to 20 to perform a method according to one of claims 1 to 15 and / or a method according to claim 16. [22] Computer-readable medium on which the computer program according to claim 21 is stored.

Images