Method for providing control data for an ophthalmic laser of a treatment device

Abstract

Method for providing control data for an ophthalmic laser (12) of a treatment device (10) for treating a cornea (16) of an eye, the method comprising the following steps carried out by means of a control device (18): - determining (S10) eye parameters from predetermined examination data; - determining (S12) a respective diameter for respective optical zones (OZ) as a function of the determined eye parameters by the control device (18), wherein a diameter for treating the cornea (16) is selected from the determined diameters of the optical zones (OZ); - Providing (S14) control data comprising the selected diameter of the optical zone (OZ) - wherein three diameter ranges are specified, wherein a first diameter range with diameters greater than a first diameter value, a second diameter range with diameters in the range from the first diameter value to a second diameter value, wherein the first diameter value is greater than the second diameter value, and a third diameter range with diameters smaller than the second diameter value are provided, wherein one of the three diameter ranges with the associated diameters is determined depending on the eye parameters; wherein the first diameter range is provided if one or more of the following conditions apply: - an astigmatism above a given astigmatism value; - a second treatment for myopia correction after myopia correction has been performed as the first treatment; - a second treatment for hyperopia correction after hyperopia correction has been performed as the first treatment; - myopia with a spherical aberration of more than 0.25 diopters; - hyperopia with a spherical aberration below 0 diopters; the second diameter range is provided if one or more of the following conditions apply: - an initial treatment for myopia correction; - an initial treatment for hyperopia correction; - a second treatment for myopia correction after hyperopia correction has been performed as the first treatment; - myopia with a spherical aberration of less than 0.25 diopters; - a hyperopia with a spherical aberration in a range of 0 diopters to 0.25 diopters; the third diameter range is provided if one or more of the following conditions apply: - a second treatment for hyperopia correction after myopia correction has been performed as the first treatment; - hyperopia with a spherical aberration of more than 0.25 diopters.

Description

The invention relates to a method for providing control data for an ophthalmological laser of a treatment device for treating a cornea of an eye. Furthermore, the invention relates to a control device which is configured to carry out the method, to a treatment apparatus having such a control device, to a computer program comprising instructions which cause the treatment apparatus to execute the method, and to a computer-readable medium on which the computer program is stored.Treatment devices and methods for controlling ophthalmological lasers for correcting an optical defect vision and / or pathologically or unnaturally modified regions of the cornea (cornea) are known in the prior art. In this case, for example, pulsed lasers and a beam focusing device can be designed such that laser pulses cause photodisruption and / or ablation in a focus located within the organic tissue in order to remove a tissue, in particular a tissue lenticle, from the cornea.In such a treatment, an optical zone and a transition zone adjoining it are usually defined as the treatment region. The optical zone provides the planned diameter for the treatment in which the optically effective zone for changing the optical properties of the cornea is to be carried out. The transition zone adjoining it is provided to provide a gentle transition from the separated tissue of the optical zone to the remaining corneal tissue. The selection of the diameter of the optical zone is usually freely selectable in treatment apparatuses and is established according to experience. However, these do not have to fit optimal diameters for optical zones, since in particular several factors have to be taken into account in defining an optimized diameter for the optical zone.From DE 10 2021 101 119 A1 a method for controlling an eye surgery laser for separating a volume body having a predefined posterior interface and a predefined anterior interface from a human or animal cornea is known, comprising controlling the laser by means of a control device in such a way that it emits pulsed laser pulses into the cornea in a shot sequence, wherein the interfaces are generated by means of an interaction of the individual laser pulses with the cornea by the generation of a plurality of cavitation bubbles generated by photodisruption, wherein a minimum diameter of the volume body is determined orthogonally to an optical axis of the volume body as a function of at least one diopter value for the volume body and as viewed from a predefined thickness of the volume body in a direction of the optical axis.DE 10 2005 013 558 A1 discloses a method and a device for changing the properties of an optical system by means of a continuous multifocal profile, wherein the profile comprises a component for increasing the depth of focus of the optical system and the component for increasing the depth of focus is calculated at least from a Zernike polynomial of fourth order, a change in the basic refraction of the eye is prevented by the component for increasing the depth of focus additionally being calculated from a Zernike polynomial of second order.WO 2018 / 156769 A1 discloses a method for reproducing a cornea of an eye, which method comprises applying ablation energy to the cornea of the eye and controlling the distribution of the ablation energy on the cornea of the eye. The distribution of ablation energy is controlled by causing the ablation energy to create an ablation zone having an optical zone in a central portion of the anterior surface of the cornea and a transition zone peripheral to the optical zone, and determining a shape of the transition zone by selecting between a cubic spline function and a complementary error function.DE 694 09 285 T2 discloses a system for laser treatment of refractive errors of the eye.From WO 00 / 27 324 A1 an apparatus and a method for performing a presbyopia correction operation are known.It is therefore an object of the invention to simplify and / or improve the planning for the treatment of a cornea of an eye, in particular the determination of a diameter of an optical zone.This object is achieved by the independent patent claims. Advantageous refinements of the invention are disclosed in the dependent patent claims, the following description and the figures.The invention is based on the idea that depending on the treatment to be performed, which can be determined from predetermined eye parameters, diameters for optical zones that are optimized for the treatment are automatically provided. For example, at least one diameter can be determined for the optical zone and / or diameter ranges can be provided, i.e. a range of diameters which are between two diameter values and which are optimized for the planned treatment.One aspect of the invention relates to a method for providing control data for an ophthalmological laser of a treatment apparatus for treatment of a cornea of an eye, wherein the method has the following steps carried out by means of a control device. A control device can be understood to mean a device or a device component, in particular a computer or a processor, which can automatically perform the following steps according to predetermined parameters and / or in which individual steps can be performed according to user inputs.In the method, eye parameters are ascertained from predetermined examination data, a respective diameter for respective optical zones is ascertained as a function of the ascertained eye parameters by the control device, wherein a diameter for treatment of the cornea is selected from the ascertained diameters of the optical zones, and control data is provided which comprise the selected diameter of the optical zone.In other words, predetermined examination data can first be provided to the control device, for example by transmitting the examination data from an examination apparatus to the control device via a wireless and / or wired connection. Alternatively or additionally, the examination data can also be input manually into the control device via a user interface. The control device can determine eye parameters from this, such as, for example, refractive error data, in particular, myopie values, hyperopia values, astigmatism values and / or values for a spherical aberration. Furthermore, values for a pupil size, in particular in scotopic conditions or a maximized pupil, can also be provided for example to the eye parameters. Preferably, information about pretreatments of the eye and / or a currently planned treatment can also be provided in the eye parameters.From these eye parameters, the control device can preferably automatically determine at least one diameter for an optical zone that is optimized with the previously determined eye parameters. This can be carried out, for example, by means of look-up tables and / or predefined calculation formulae and / or decision trees. Preferably, a plurality of diameters may be provided, each diameter defining a further optical zone, all of which may be optimized for the determined eye parameters. This means that there may be several diameters possible for a treatment, which can then be provided to a user for selection. A user can then, for example via a user interface, select one of the provided diameters for treatment of the cornea. If, for example, only one diameter for the optical zone is determined by the control device, this can preferably be selected automatically by the control device.The selected diameter of the optical zone can then be provided in the form of control data to the treatment device which, when the control data are executed, effects treatment of the cornea of the eye with the selected diameter of the optical zone.Preferably, diameters for the optical zone can be provided by the control device which provide a change in a corneal curvature by reducing regression and / or regrowth of an epithelial layer of the cornea and which are smaller than the diameter of the cornea.The invention provides the advantage that planning a corneal treatment for a user is facilitated because the optimized diameters are automatically determined depending on the eye parameters and therefore no further considerations and / or calculations are necessary for the user. Furthermore, the treatment results can thus be improved, since the optimized diameters can always be used for the optical zones.Furthermore, according to the invention, it is provided that three diameter ranges are specified, wherein a first diameter range with diameters greater than a first diameter value, a second diameter range with diameters in the range from the first diameter value to a second diameter value, wherein the first diameter value is greater than the second diameter value, and a third diameter range with diameters less than the second diameter value are provided, wherein one of the three diameter ranges with the associated diameters is defined as a function of the eye parameters. This means that the diameters present in the provided diameter range can subsequently be offered for selection. In other words, the control device can provide diameters which are divided within three predetermined diameter ranges. A first or upper diameter range comprises diameters above a first diameter value and a third or lower diameter range comprises diameters below a second diameter value. In a second or middle diameter range, diameters are provided which lie within the range of the first and second diameter values. Thus, the control device can define that diameter range with the diameters located therein which best matches the present eye parameters.It is contemplated that the first diameter range will be provided if one or more of the following conditions apply:an astigmatism is above a predetermined astigmatism value, in particular greater than or equal to 2.5 diopters;a second treatment for a myopia correction is present after a myopia correction has been carried out as the first treatment;a second treatment for hyperopia correction is present after a hyperopia correction has been carried out as the first treatment;a myopia having a spherical aberration above 0.25 diopters;Hyperopia with spherical aberration below 0 diopters.The second diameter range may be provided if one or more of the following conditions apply:performing a first treatment for a correction of myopia;performing a first treatment for hyperopia correction;a second treatment for a myocardial correction is present after a hyperopia correction has been carried out as the first treatment;a myopia having a spherical aberration below 0.25 diopters;a hyperopia having a spherical aberration in a range from 0 diopters to 0.25 diopters.The third diameter range may be provided if one or more of the following conditions apply:a second treatment for hyperopia correction is performed after a myopia correction is performed as the first treatment;Hyperopia with spherical aberration above 0.25 diopters.Thus, the controller may determine which of the three diameter ranges is determined in the form of a look-up table or decision tree to select the diameters therein for the optical zone.The invention also comprises developments, by means of which additional advantages result.A development provides that the eye parameters comprise at least one pupil diameter, in particular a pupil diameter of a scotopic pupil, wherein diameters which are greater than the pupil diameter are provided for the optical zone. This means that the diameters of the provided optical zones cover at least the region of the pupil, in particular of a pupil with a maximized diameter. Preferably, the diameters of the optical zones can be limited downward by the determined pupil diameter and upward by the diameter of the cornea, and alternatively or additionally, the diameters of the optical zones can be limited upward as a function of further parameters, which can preferably be determined from the eye parameters. This development has the advantage that, in particular in the case of weak lighting conditions, such as darkness, no adverse effects occur after the treatment.A further development provides that a correction type is determined from the eye parameters, in particular a myopie correction or a hyperopia correction, wherein larger diameters of the optical zone are provided for correction types in which a major portion of an ablation takes place at a peripheral position of the cornea than for correction types in which the major portion of the ablation takes place at a central position of the cornea. A central position of the cornea can be defined, for example, by a pupil center point and / or a cornea vertex point, and a peripheral position radially spaced apart from this center. If, for example, a hyperopia correction is planned, a major portion or a center of gravity of the ablation can take place at a peripheral position of the cornea, since a lentivirus in the form of a diverging lens is removed from the cornea in order to compensate for the hyperopic portion. In such hyperopia correction, larger diameters can be provided for the optical zone than, for example, for a myopia correction, in which more tissue is removed centrally than peripherally. By a major proportion of ablation is meant that at least 60%, preferably more than 80%, of the tissue to be removed is at peripheral positions. Preferably, transepithelial ablations can provide diameters for the optical zone that provide for treatment of stroma. This development results in the advantage that the diameters for the optical zone can be optimized as a function of the planned correction.Preferably, for the diameter ranges, the first diameter value may be 7 mm and the second diameter value may be 6.5 mm. This means that the first diameter range comprises diameters with greater than 7 mm, the second diameter range comprises diameters of 6.5 mm to 7 mm and the third diameter range comprises diameters of less than 6.5 mm. These diameter values represent statistically determined limit values, which have been found to be particularly advantageous for the treatment of respective conditions described below.A further development provides that the following calculations are carried out for determining the diameters of the optical zone:- OZ 1= 7,6 + 0,15 * min(Sph; Sph+Cyl; 0);- OZ 2= 7,8 - 0,3 * max(Sph; Sph+Cyl; 0);- OZ 3= 7,5 - 0,25 * abs(Cyl); where OZ 1, OZ 2 and OZ 3 are respective diameter values for the optical zone, Sph is a spherical refraction value and Cyl is a cylindrical refraction value, wherein a minimum value is selected from OZ 1, OZ 2 and OZ 3 or a maximum value from OZ 1, OZ 2 and OZ 3 or a mean value from OZ 1, OZ2and OZ3as diameter. The decision as to whether the minimum value, maximum value or mean value is selected can be carried out, for example, as a function of the planned treatment, in particular whether corneal volume is to be saved, a treatment result is to be maximized or a compromise between the aforementioned is to be provided.A further aspect of the invention relates to a method for controlling a treatment device. The method comprises the method steps of at least one embodiment of a method as described above. Furthermore, the method for controlling the treatment device also comprises the step of transmitting the provided control data to at least one ophthalmological laser of the treatment device and controlling the treatment device and / or the laser with the control data.The respective method can comprise at least one additional step which is executed exactly when a use case or an application situation occurs which has not been explicitly described here. The step may comprise, for example, outputting an error message and / or outputting a request to input a user feedback. Additionally or alternatively, it can be provided that a default setting and / or a predetermined initial state is set.A further aspect of the invention relates to a control device which is designed to carry out the steps of at least one embodiment of one or both of the methods described above. For this purpose, the control device can have a computing unit for electronic data processing, such as a processor. The computing unit can comprise at least one microcontroller and / or at least one microprocessor. The computing unit can be designed as an integrated circuit and / or microchip. Furthermore, the control device can comprise an (electronic) data memory or a storage unit. The data memory can store program code by which the steps of the respective embodiment of the respective method are encoded. The program code can comprise the control data for the respective laser. The program code can be executed by means of the arithmetic unit, as a result of which the control device is caused to execute the respective embodiment. The control device can be designed as a control chip or control device. The control device can be comprised, for example, by a computer or computer group.A further aspect of the invention relates to a treatment apparatus having at least one ophthalmic surgical or ophthalmic laser and a control device which is designed to carry out the steps of at least one embodiment of one or both of the methods described above. The respective laser can be designed to at least partially separate a predefined corneal volume with predefined boundary surfaces of a human or animal eye by means of optical breakthrough, in particular to at least partially separate it by means of photodisruption and / or to ablate corneal layers by means of (photo)ablation and / or to bring about a laser-induced refractive index change in the cornea and / or the eye lens and / or to increase a cross-linking (cross-linking) of the cornea.In a further advantageous development 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 900 nm and 1200 nm, at a respective pulse duration between 1 fs and 1 ns, preferably between 10 fs and 10 ps, and at a repetition frequency greater than 10 kilohertz (kHz), preferably between 100 kHz and 100 megahertz (MHz). The use of such 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 region is subsumed in laser technology under the term "deep ultraviolet". This advantageously prevents unintentional damage to the cornea from occurring due to these very short-wave and high-energy beams. Photodisruptive and / or ablative lasers of the type used here usually introduce pulsed laser radiation with a pulse duration between 1 fs and 1 ns into the corneal tissue. As a result, the power density of the respective laser pulse required for the optical breakdown can be spatially narrowly limited, so that a high cutting accuracy is made possible during the generation of the boundary surfaces. The wavelength range selected can also be, in particular, the range between 700 nm and 780 nm.In a further advantageous development of the treatment apparatus according to the invention, the control device can have at least one storage device for at least temporarily storing at least one control data set, wherein the control data set or sets comprise control data for positioning and / or for focusing individual laser pulses in the cornea / cornea; and can have at least one beam device for beam guidance and / or beam shaping and / or beam deflection and / or beam focusing of a laser beam of the laser.A further aspect of the invention relates to a computer program. The computer program comprises instructions which form, for example, a program code. The program code can comprise at least one control data set with the respective control data for the respective laser. When the program code is executed by means of a computer or a computer group, it is caused to execute the method described above or at least one embodiment thereof.A further aspect of the invention relates to a computer-readable medium (storage medium) on which the aforementioned computer program or the instructions thereof are stored. For executing the computer program, a computer or a computer cluster can access the computer-readable medium and read its content. The storage medium is embodied, for example, as a data memory, in particular at least partially as a volatile or nonvolatile data memory. A non-volatile data memory can be a flash memory and / or an SSD (solid state drive) and / or a hard disk. A volatile data memory can be a RAM (random access memory). The instructions may be present, for example, as source code of a programming language and / or as assembler and / or as binary code.Further features and advantages of one of the described aspects of the invention can be derived from the developments of another of the aspects of the invention. The features of the embodiments of the invention can thus be present in any combination with one another, provided they have not been explicitly described as mutually exclusive.In addition to the diameter of the optical zone, the control data can comprise a respective data record for positioning and / or focusing individual laser pulses in the cornea. Additionally or alternatively, a respective data set for setting at least one beam device for beam guidance and / or beam shaping and / or beam deflection and / or beam focusing of a laser beam of the respective laser can be included in the control data.Additional features and advantages of the invention are described below with reference to the figure(s) in the form of advantageous exemplary embodiments. The features or combinations of features of the exemplary embodiments described below can be present in any combination with one another and / or the features of the embodiments. That is, the features of the embodiments may supplement and / or replace the features of the embodiments, and vice versa. Embodiments are therefore also to be considered as included and disclosed by the invention, which are not explicitly shown or explained in the figures, but which emerge from the exemplary embodiments and / or embodiments and can be generated by separate combinations of features. Embodiments are therefore also to be regarded as disclosed which do not have all features of an originally formulated claim or go beyond or deviate from the combinations of features set forth in the references back of the claims. The following shows the exemplary embodiments: FIG. 1 shows a schematic illustration of a treatment apparatus according to an exemplary embodiment; FIG. 2 shows a schematic method diagram for providing control data according to an exemplary embodiment.In the figures, identical or functionally identical elements are provided with the same reference numerals.FIG. 1 shows a schematic representation of a treatment device 10 with an ophthalmological laser 12 for the removal of a volume body 14 from a human or animal cornea (cornea) 16 by means of photodisruption and / or ablation. The volume body 14 can be, for example, a lentivirus which can be separated from the cornea 16 by the eye surgical laser 12 for correction of a defective vision. A correction profile or a geometry of the volume body 14 to be removed, which in particular comprises a diameter of an optical zone OZ in which the optically effective change for correction of defective vision takes place, can be provided or determined by a control device 18, in particular in the form of control data, so that the laser 12 emits pulsed laser pulses in a pattern predefined by the control data into the cornea 16 of the eye in order to remove the volume body 14. Alternatively, the control device 18 can be a control device 18 external with respect to the treatment apparatus 10.Furthermore, FIG. 1 shows that the laser beam 20 generated by the laser 12 can be deflected in the direction of the cornea 16 by means of a beam deflection device 22, such as a rotation scanner, for example, in order to remove the volume body 14. The beam deflection device 22 can likewise be controlled by the control device 18 in order to remove the volume body 14.The laser 12 illustrated can preferably be a photodisruptive and / or photoablative laser which is designed to emit laser pulses in a wavelength range between 300 nanometers and 1400 nanometers, preferably between 700 nanometers and 1200 nanometers, with a respective pulse duration between 1 femtosecond and 1 nanosecond, preferably between 10 femtoseconds and 10 picoseconds, and with a repetition frequency greater than 10 kilohertz, preferably between 100 kilohertz and 100 megahertz. The control device 18 optionally also has a storage device (not shown) for at least temporarily storing at least one control data set, wherein the control data set or sets comprise control data for positioning and / or focusing individual laser pulses in the cornea.When removing the volume body 14 from the cornea 16, the selection of the diameter of the optical zone OZ plays a major role in the success of the treatment. The size of the optical zone OZ can be freely selected first, wherein it has been established that optimized diameters for the optical zone OZ can be selected depending on eye parameters, for example a type of refraction correction and / or pretreatments of the cornea 16, but these are not immediately apparent. In order to assist a user in defining the diameter of the optical zone and thus to improve the treatment, the method shown in FIG. 2 can be carried out by the control device 18 and / or by a control device external to the treatment apparatus 10, which control device belongs to a planning device, for example.FIG. 2 shows a schematic method diagram for providing control data for an ophthalmological laser 12 of a treatment apparatus 10 for treatment of a cornea 16 of an eye.In a step S 10, eye parameters can be determined from predetermined examination data, wherein the examination data can be provided from previously performed diagnostic measurements. The eye parameters relate here to properties of the eye to be treated and / or of the cornea 16, such as, for example, a pupil diameter, preferably in the case of a scotopic pupil, refractive error data of the eye, in particular myopia, hyperopia and astigmatism values with respective spherical aberrations and / or which treatment is to be carried out and which treatments have already been carried out.In a step S 12, at least one diameter of the optical zone OZ can be determined by the control device, which is optimized for the determined eye parameters. In particular, it can be provided that a plurality of diameters are determined, wherein a respective diameter provides a further optical zone OZ for the treatment.In order to determine the optimized diameter of the optical zone OZ, the control device can take into account various eye parameters. For example, a minimum diameter of the optical zone OZ can be defined on the basis of the pupil diameter, in particular the scotopic pupil. As a further criterion, for example, the correction type which is to be carried out for the cornea 16 can be determined, wherein, in particular for a hyperopia correction, in which a major portion of the ablation takes place at a peripheral position of the cornea, a larger diameter is provided for the optical zone OZ than for a myopie correction.Particularly preferably, at least three diameter ranges with diameters smaller than 6.5 mm, with diameters larger than 7 mm and diameters between 6.5 mm and 7 mm can be stored in the control device 18. Depending on the eye parameters present, it can then be decided by the control device 18 which diameter range is offered for selection, wherein, for example, in one or more of the following conditions, a diameter range with diameter values greater than 7 mm is provided:an astigmatism is above a predetermined astigmatism value, in particular greater than or equal to 2.5 diopters;a second treatment for a myopia correction is present after a myopia correction has been carried out as the first treatment;a second treatment for hyperopia correction is present after a hyperopia correction has been carried out as the first treatment;a myopia having a spherical aberration above 0.25 diopters;Hyperopia with spherical aberration below 0 diopters.If one or more of the following conditions are present, a diameter range with values between 6.5 mm and 7 mm can be provided by the control device 18.performing a first treatment for a correction of myopia;performing a first treatment for hyperopia correction;a second treatment for a myocardial correction is present after a hyperopia correction has been carried out as the first treatment;a myopia having a spherical aberration below 0.25 diopters;a hyperopia having a spherical aberration in a range from 0 diopters to 0.25 diopters.The diameter range with diameters below 6.5 mm can be provided for selection if one of the following conditions is present:a second treatment for hyperopia correction is performed after a myopia correction is performed as the first treatment;Hyperopia with spherical aberration above 0.25 diopters.Alternatively or additionally, the following calculation formulae can also be stored in the control device 18, by means of which the optimized diameter for a respective treatment can be determined:- OZ 1= 7,6 + 0,15 * min(Sph; Sph+Cyl; 0);- OZ 2= 7,8 - 0,3 * max(Sph; Sph+Cyl; 0);- OZ 3= 7,5 - 0,25 * abs(Cyl), where OZ 1, OZ 2 and OZ 3 are respective diameter values for the optical zone, Sph is a spherical refraction value and Cyl is a cylindrical refraction value. The numerical values can in this case originate from statistics that have been applied to previous patient data, in particular from fit values. After OZ 1, OZ 2 and OZ 3 are determined, for example, a minimum value, a maximum value or an average value may be determined from these values to provide the diameter for the optical zone OZ.Preferably, a minimum value can be used when a volume saving is desired, a maximum value at a maximized correction result and the average value at a compromise between volume saving and maximizing the treatment result. In particular, a nomogram can thus be calculated, in which an optimized diameter for the optical zone OZ can be read from a desired refractive power correction. For example, the following value pairs of refractive power correction to diameter of the optical zone can be obtained in this way:(-18 D; 5.5 mm), (- 15 D; 5.9 mm), (- 12 D; 6.2 mm), (- 9 D; 6.6 mm), (- 6 D; 7.0 mm), (- 3 D; 7.4 mm), (2 D; 7.5 mm), (4 D; 6.9 mm), (6 D; 6.3 mm), (8 D; 5.7 mm).Particularly preferably, in the case of transepithelial ablations, the meridional refractive power can also be related to the uncertainty of the epithelial thickness in order to ensure that a relevant part of the correction is generated in the stroma. This means that larger diameters can be scheduled for this purpose by the control device 18, such as the following value pairs:(-15 D; 6.3 mm), (-10 D; 6.5 mm), (-4 D; 6.8 mm), (-2 D; 7.0 mm), (-1 D; 7.5 mm), (1 D; 8.0 mm), (2 D; 7.5 mm), (3 D; 7.2 mm), (4 D; 7.0 mm).After the diameters for the optical zone OZ have been determined, these can be provided to a user who can select a diameter for treatment of the cornea 16.Finally, in a step S 14, control data can be provided, by means of which the laser 12 and / or the beam deflection device 22 can be controlled in order to remove the volume body 14 from the cornea 16, wherein the volume body 14 comprises the selected diameter of the optical zone OZ.Overall, the examples show how a diameter for an optical zone OZ can be determined in an improved manner by the invention.

Claims

Method for providing control data for an ophthalmological laser (12) of a treatment apparatus (10) for treating a cornea (16) of an eye, wherein the method has the following steps carried out by means of a control device (18): - ascertaining (S10) eye parameters from predetermined examination data; - ascertaining (S12), by the control device (18), a respective diameter for respective optical zones (OZ) as a function of the ascertained eye parameters, wherein a diameter for treating the cornea (16) is selected from the ascertained diameters of the optical zones (OZ); providing (S14) control data comprising the selected diameter of the optical zone (OZ), - wherein three diameter ranges are provided, wherein a first diameter range with diameters greater than a first diameter value, a second diameter range with diameters in the range from the first diameter value to a second diameter value, wherein the first diameter value is greater than the second diameter value, and a third diameter range with diameters smaller than the second diameter value are provided, wherein one of the three diameter ranges with the associated diameters is defined depending on the eye parameters; wherein the first diameter range is provided if one or more of the following conditions apply: - an astigmatism above a predetermined astigmatism value; - a second treatment for a myopie correction after a myopie correction has been carried out as the first treatment; a second treatment for hyperopia correction after a hyperopia correction has been carried out as the first treatment; a myopie having a spherical aberration above 0.25 diopters; a hyperopia having a spherical aberration below 0 diopters; wherein the second diameter range is provided if one or more of the following conditions apply: a first treatment for a myopie correction; a first treatment for a hyperopia correction; a second treatment for a myopie correction after a hyperopia correction has been carried out as the first treatment; a myopie having a spherical aberration below 0.25 diopters; a hyperopia having a spherical aberration in a range from 0 diopters to 0.25 diopters; wherein the third diameter range is provided if one or more of the following conditions apply: - a second treatment for hyperopia correction after a myopia correction has been carried out as the first treatment; - a hyperopia with a spherical aberration above 0.25 diopters.Method according to claim 1, wherein the eye parameters comprise at least one pupil diameter, in particular a pupil diameter of a scotopic pupil, wherein diameters are provided for the optical zone that are larger than the pupil diameter.Method according to one of the preceding claims, wherein a correction type is determined from the eye parameters, in particular a myopie correction or a hyperopia correction, wherein larger diameters of the optical zone (OZ) are provided for correction types in which a major proportion of ablation takes place at a peripheral position of the cornea (16) than for correction types in which the major proportion of ablation takes place at a central position of the cornea (16).The method according to any of the preceding claims, wherein the first diameter value is 7 mm and the second diameter value is 6.5 mm.Method according to one of the preceding claims, wherein the following calculations are carried out for determining the diameters of the optical zone (OZ): - OZ 1= 7,6 + 0,15 * min(Sph; Sph + Cyl; 0); - OZ 2= 7,8 - 0,3 * max(Sph; Sph + Cyl; 0); - OZ 3= 7,5 - 0,25 * abs(Cyl); where OZ 1, OZ 2, and OZ 3 are respective diameter values for the optical zone (OZ), Sph is a spherical refraction value and Cyl is a cylindrical refraction value, wherein - a minimum value is selected from OZ 1, OZ 2 and OZ 3 or - a maximum value is selected from OZ 1, OZ 2 and OZ 3 or - an average value is selected from OZ 1, OZ2 and OZ3 as diameter.Method for controlling a treatment device (10), wherein the method comprises the following steps: - the method steps of a method according to one of the preceding claims, and - transmitting the provided control data to a respective ophthalmological laser (12) of the treatment device (10); and - controlling the laser (12) with the control data.Control device (18) which is configured to carry out a respective method according to one of the preceding claims.Treatment device (10) having at least one ophthalmological laser (12) for separating a corneal volume (14) of a human or animal eye by means of optical breakthrough, in particular by means of photodisruption and / or photoablation, and at least one control device (18) according to Claim 7.A computer program comprising instructions for causing the treatment apparatus (10) according to claim 8 to execute a method according to any one of claims 1 to 5 and / or a method according to claim 6.A computer readable medium having stored thereon a computer program according to claim 9.

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