Method for predicting the future position of an eye target point to compensate for image evaluation delays; control device and treatment device

Abstract

The invention relates to a method for determining the position of a target point in a human or animal eye (16), in particular the position of a target point in the cornea (16) of the eye, during a medical treatment of the eye (16), comprising the following steps allowing an improved targeting accuracy of triggering a laser pulse to the respective target point: capturing (S1) respective images of the eye (16) at least at a first time point and at a later second time point, determining (S2) motion information about the movement of the eye (16) and / or the target point based on the respective images, and determining (S3) prediction data based on the motion information, the prediction data comprising a prediction of the future position and / or orientation of the target point at a later time point, wherein the later time point is temporally separated from the second time point by a period of time, the duration of which is at least derived from a delay of the image evaluation, in particular steps S1 and / or S2 and / or S3.

Description

Technical Field

[0001] The invention relates to a method for determining the position of a target point of a human or animal eye, in particular of the cornea of ​​the eye, during medical treatment of the eye. A second aspect of the invention relates to a method for controlling an ophthalmic surgical laser of a treatment device during treatment of the cornea of ​​a human or animal eye, depending on the position and / or orientation of the target point of the eye. A third aspect of the invention relates to a control device. Another aspect of the invention relates to a treatment device. Furthermore, the invention relates to a computer program and a computer-readable medium. Background Art

[0002] Therapeutic devices and methods for controlling ophthalmic surgical lasers for correcting optical visual disturbances and / or pathological or unnaturally altered areas of a patient's cornea are known in the prior art. In this case, for example, pulsed lasers and beam arrangements can be formed such that the laser pulses cause photodisruption and / or photoablation in a focal point located within the organic tissue in order to remove tissue, in particular tissue lenticules, from the cornea.

[0003] In order to achieve the best treatment result, it is required that the laser pulse enters the target point of the eye, in particular the target point of the cornea of ​​the eye, with the highest possible accuracy. In this regard, for the highest possible accuracy, it is advantageous if the eye is captured particularly continuously by the capture device. This can also be referred to as tracking. In other words, the movement of the eye can be tracked. The movement of the eye can then be used to determine the corresponding target point of the laser pulse.

[0004] From EP 1 923 026 B1 a system for ablating the cornea of ​​an eye is known, in which a nominal target is determined for each laser pulse before ablating the cornea of ​​the eye. From the time delay signal received by the eye tracker, the distribution of the laser pulse to the actual target position is calculated. In order to correct errors, more laser pulses with associated nominal target positions can be defined. SUMMARY OF THE INVENTION

[0005] It is an object of the present invention to allow an improved targeting accuracy for triggering laser pulses onto corresponding target points.

[0006] According to the invention, this object is achieved by the subject matter of the independent claim. Advantageous embodiments with expedient refinements are the subject matter of the dependent claims.

[0007] A first aspect of the invention is based on a method for determining the position of a target point of a human or animal eye, in particular of the cornea of ​​the eye, during a medical treatment of the eye. According to the invention, the method comprises the following steps:

[0008] - capturing respective pictures of said eye at least at a first point in time and at a later second point in time,

[0009] - determining movement information about the movement of the eye and / or the target point based on the corresponding pictures, and

[0010] - based on the motion information, determining prediction data, the prediction data comprising a prediction of a future position and / or orientation of a target point at a later point in time, wherein the later point in time is separated from the second point in time by a period of time, the duration of which is at least derived from a delay of the image evaluation.

[0011] Each picture of the eye can be a picture generated by any preferred imaging capture method. For example, the capture method can be thermal imaging, ultrasonic sensor technology or any other imaging method. Preferably, the picture of the eye is a corresponding camera image. In other words, the individual camera images of the eye can be captured at least at a first point in time and a later second point in time. For example, this can be achieved by a camera. In particular, the pictures or camera images are different frames of a motion image or video signal, respectively. In particular, the pictures are each digital pictures, thus, for example, image files or video files. In particular, a continuous video signal can be captured by a camera, wherein the individual pictures can be parts of the video signal, in particular single images or frames of the video signal.

[0012] The picture captured at the first time point may represent or image the eye at or at the first time point, respectively. The picture captured at the first time point is also referred to as the first picture below. The picture of the eye captured at the second time point may represent or image the eye at or at the second time point. The picture captured at the second time point is also referred to as the second picture below. Wherein, the second time point is after the first time point in time. In other words, the second picture represents the eye at a time point later than the first picture. In other words, the second picture can image the eye at a time point later than the first picture. Wherein, the present disclosure with two pictures at two different time points will be understood purely by way of example. Of course, corresponding pictures can also be captured at more than two time points, so in particular at two, three, four, five, six, seven, eight, etc. time points. Similarly, more than one picture can be captured at each time point or at each time point. Therefore, for example, more than one picture capturing the eye at the first time point can be provided.

[0013] From each picture, in particular the first picture and the second picture, motion information about the movement of the eye and / or the target point can be determined. As mentioned above, if more eye pictures are captured, rather than just the first picture and the second picture, they can of course also be used to determine the motion information. For example, the relative movement of the eye and / or the target point between the first picture and the second picture can be determined as motion information. In the case of multiple pictures, the corresponding relative movement between the pictures can be determined as part of the motion information. For example, the corresponding relative movement between two images captured at adjacent time points can be captured or determined. Motion information or relative movement can be determined and indicated in the form of corresponding vectors (in the case of translational motion) and / or angles (in the case of rotational motion), for example. Among them, motion information of different degrees of freedom, such as three independent translational degrees of freedom and / or three independent rotational degrees of freedom, can be determined together and / or independently of each other. Acceleration and / or velocity or corresponding values ​​of acceleration and / or corresponding values ​​of velocity can constitute motion information or be part of motion information.

[0014] Based on the motion information, a prediction of the future position and / or orientation of the target point at a later time point can then be determined. The prediction can be determined as part of the prediction data. Wherein, the later time point is separated from the second time point in time by a period of time, the duration of which is at least derived from the delay of the image evaluation. In other words, the position and / or orientation of the target point at such a later time point can be determined by prediction, at which the determination of the prediction data is completed and / or the prediction data is output. Therefore, the present invention is based on the following idea: in the conventional determination of the position and / or orientation of the target point based on the corresponding picture or based on the second picture at the second time point, the position and / or orientation will be determined, which has been completed at a certain time point in the past, at which time point, the determination is completed because the image evaluation is affected by the delay. Therefore, the idea of ​​the present invention is based on the fact of considering the delay, because the position and / or orientation of the eye is predicted for a later time point. In this way, the prediction data contains the predicted future position and / or orientation of the target point at a later time point, at which the image evaluation, such as the capture of the corresponding picture, the determination of the motion information and / or the determination of the prediction data, has been completed. Therefore, the time delay of the image evaluation can be compensated by the prediction. Of course, in individual cases, it may be reasonable to consider only the delay of selected method steps or only some of the method steps. In this case, it may be, for example, that the later time point is closer to the second time point than in an embodiment in which all steps are considered. Alternatively or additionally, it may certainly be advantageous to consider other and / or additional method steps or other events when determining a time period, by which the later time point starts from the second time point in the future. For example, method steps affected by the delay may be considered after determining the position and / or orientation of the target point. This will be explained in more detail later.

[0015] According to a further development, when determining the prediction data, the later time point is at most temporally separated from the first time point. In other words, while carrying out the step of determining the prediction data, the later time point can be at most at the same time period in the future as the first time point is in the past. In this way, it can be ensured that the prediction does not point too far into the future. In particular, this can be problematic in the case of movements of the human or animal eye, since the homogeneity of the movement thereof is insufficient.

[0016] According to an improved provision, the acceleration and / or speed along multiple degrees of freedom are captured independently of each other and / or evaluated independently of each other when determining the prediction data. In other words, it can be provided that the acceleration of the eye and / or the target point along multiple degrees of freedom is captured independently of each other. For example, the corresponding value of the acceleration along each of the multiple degrees of freedom is determined independently. It can be provided that the speed along multiple degrees of freedom is captured independently of each other. For example, the corresponding value of the speed along each of the multiple degrees of freedom can be determined independently of the remaining degrees of freedom. Alternatively or additionally, it can be provided that the acceleration and / or speed along multiple degrees of freedom are evaluated independently of each other when determining the prediction data. For example, it can be provided that the corresponding values ​​of the acceleration and / or speed along each degree of freedom are evaluated independently of each other for determining the prediction data or prediction. Among them, the corresponding partial prediction of the movement along each of the multiple degrees or degrees of freedom can be determined or created. Then, the prediction or prediction data can be composed of partial predictions, for example, by linear combination or addition of vectors.

[0017] A second aspect of the present invention relates to a method for controlling an ophthalmic surgical laser of a treatment device during corneal treatment of a human or animal eye according to the position and / or orientation of a target point of the eye. The method according to the second aspect of the present invention is based on the method according to the first aspect of the present invention. The method according to the second aspect further comprises the following method steps:

[0018] - determining a position specification of the laser pulse at least based on the predicted data, and

[0019] - Adjust the laser according to the position specifications.

[0020] Therefore, the method according to the second aspect of the present invention may generally include the following method steps:

[0021] - capturing corresponding pictures of the eye at least at a first time point and at a later second time point,

[0022] - determining movement information about the movement of the eye and / or the target point based on the corresponding pictures,

[0023] - determining prediction data based on the motion information, the prediction data comprising a prediction of a future position and / or orientation of the target point at a later point in time, wherein the later point in time is separated in time from the second point in time by a period of time, the duration of which is derived at least from a delay of the image evaluation, in particular steps S1 and / or S2 and / or S3,

[0024] - determining a position specification of the laser pulse at least based on the predicted data, and

[0025] - Adjust the laser according to the position specifications.

[0026] Therefore, the prediction of the future position and / or orientation of the target point is used to determine the position specification of the laser pulse. For example, the position specification of the laser pulse can be fixed in a coordinate system aligned with the eye or the cornea. In this embodiment, the movement of the eye can be relatively moved between the coordinate system aligned with the eye and the world coordinate system or the coordinate system aligned with the treatment device for performing the treatment. Therefore, the position specification of the laser pulse can be determined, for example, taking into account the predicted data, in particular the future position of the eye and / or the target point in the world coordinate system or the coordinate system aligned with the treatment device. Subsequently, the laser, in particular the ophthalmic surgery laser, can be adjusted and / or oriented corresponding to the position specification. The adjustment or orientation of the ophthalmic surgery laser can, for example, include orienting or adjusting a beam device for beam guidance and / or beam shaping and / or beam deflection and / or beam focusing of the laser beam of the laser. For example, by actuating the beam device accordingly according to the position specification, the future laser pulse can be directed to the target point.

[0027] According to a further development, the later time point is temporally separated from the second time point by a total time period, wherein the duration of the total time period is derived at least from the delay of the image evaluation and the delay of the adjustment of the laser. In other words, in the control method for an ophthalmic surgical laser, it is provided that within the total time period temporally separated from the second time point by the later time point, the delay of the adjustment of the laser is taken into account in addition to the delay of the image evaluation. The laser can thus be adjusted to a position specification that takes into account the future position of the target point corresponding to the prediction. In this way, the eye movement predicted within the total time period can already be taken into account when adjusting the laser. This allows a more accurate adjustment of the laser.

[0028] According to a refinement, a third image of the eye is captured at a third point in time, wherein the third point in time is temporally after the second point in time but before the later point in time, wherein in particular the prediction as part of the prediction data is checked at least on the basis of the third picture. In other words, it can be provided that a third picture of the eye is captured at a third point in time. Therein, the third point in time is temporally between the second point in time and the later point in time. Advantageously, the prediction as part of the prediction data is checked at least on the basis of the third picture. It should be explicitly pointed out here that the designation "third picture" does not mean that the prediction data is based only on the first picture and the second picture. Of course, within the scope of this refinement, the motion information can also be determined based on a plurality of images at more than two points in time, and / or the prediction or prediction data are correspondingly based on corresponding pictures at more than two points in time. Therefore, based on the third picture, the validity and quality of the prediction as part of the prediction data can be checked respectively. The refinement is based on the idea that at the third point in time when the third picture is captured, due to the delay in adjusting the laser, it can no longer be oriented or adjusted based on the position and / or orientation of the target point derived from the third picture. Thus, despite the presence of a newer picture, i.e. the third picture, the laser is adjusted to the position specification derived therefrom according to the prediction or prediction data as described above. The third point in time is in particular between the second point in time and the later point in time, so that the image evaluation of the third picture is present or determined before the triggering of the laser pulse. Thus, the laser, which was previously adjusted or directed based on the prediction derived from the second picture at the second point in time, etc., can no longer be adjusted relative to the position specification, but it is possible to enable or disable the laser pulse, depending on how good the prediction proved to be within the inspection range based on the third picture.

[0029] According to an improved provision, further motion information is determined at least based on the third picture, and further prediction data including a further prediction of the future position and / or orientation of the target point at a later time point is determined based on the further motion information. The prediction or prediction data can be based on the second picture as the latest picture at the corresponding prediction time point. The further prediction data or further prediction can be based on the latest picture at the third time point, i.e. the third picture. Therefore, the further prediction data can more accurately predict the position and / or orientation of the target point at a later time point, because the prediction spans a shorter time period than the prediction data based on the second picture at the second time point. The prediction or prediction data can be checked based on the further prediction data or further prediction. For example, it can be determined in the check to what extent the prediction and the further prediction are consistent or deviate from each other. Here, it needs to be explained again that the second picture can be the latest picture for adjusting the laser for the laser pulse, which will take effect at a later time point, because there is a delay in the laser and in performing the image evaluation. Based on the further prediction data or further prediction, it is no longer possible to adjust the laser for the laser pulse that will occur at a later time point due to the total delay. However, since only the delay of the image evaluation is significant for a predictive inspection based on a further prediction, the inspection may still be carried out before a later point in time at which the laser will be triggered.

[0030] According to an improved provision, as a function of the result of the check prediction, in particular as a function of further prediction data, a laser pulse for a position specification previously adjusted based on the prediction data is enabled, or a command is given to newly adjust the laser to an updated position specification. Specifically, for example, if the deviation between the prediction and the further prediction or between the prediction data and the further prediction data is less than a predetermined threshold, the laser pulse can be enabled, for example, accurately. Similarly, if the aforementioned deviation is greater than a predetermined threshold, the laser can be commanded to newly adjust to an updated position specification. As already described above, the position specification is derived from a prediction of the position and / or orientation of the target point at a later point in time. If the above-mentioned deviation exceeds a threshold, an updated position specification can be determined. Furthermore, the laser can be adjusted or oriented according to the updated position specification.

[0031] The updated position specification can be implemented, for example, based on the prediction of the future position and / or orientation of the target point at a later time point, which is after the later time point in time. This prediction of the position and / or orientation of the target point at a later time point can be implemented similarly to the prediction of the future position and / or orientation of the target point at a later time point. In this case, similar motion information about the movement of the eye and / or the target point can be determined at least based on the second picture and the third picture. The prediction of the later time point can then be determined based on the motion information determined from the second picture and the third picture. However, since it is similar to the prediction for determining the future position and / or orientation of the target point at a later time point, it will not be repeated here.

[0032] According to an improved regulation

[0033] - at least a fourth photograph of the eye captured at approximately a later point in time,

[0034] - determining the actual position and / or orientation of the target point at a later point in time based on the fourth picture,

[0035] - comparing the actual position of the eye at the later point in time with the prediction as part of the prediction data and / or with the further prediction as part of the further prediction data, and

[0036] - depending on the result of the respective comparison, changing the first algorithm for determining the prediction data and / or the second algorithm for determining the further prediction data.

[0037] If the individual pictures, thus for example the first picture, the second picture, the third picture and / or the fourth picture, are part of a video signal, then exactly that frame of the video signal can be selected as the fourth picture, the capture time of the fourth picture being closest to the later time point. Therefore, the fourth picture is related to the eye approximately at the later time point. In other words, the fourth picture images the eye approximately at the later time point. Therefore, the position and / or orientation that the target point actually has at the later time point can be determined based on the fourth picture. By comparing the actual position of the eye at the later time point with the prediction of the position of the eye at the later time point (which is part of the prediction data), it can be determined or confirmed how good the prediction is. For example, the quality of the prediction can be evaluated and quantified by a value, which indicates the deviation between the actual position and the predicted position. By comparing the actual position of the eye at the third time point with the further prediction of the position of the eye at the later time point (which is part of the further prediction data), it can be determined or confirmed how good the further prediction is. For example, the quality of the further prediction can be evaluated and quantified by a value, which indicates the deviation between the actual position and the predicted position.

[0038] Depending on the deviation between the actual position of the eye and the prediction, the first algorithm for determining the prediction or the prediction data can be changed, i.e. trained, refined or adapted. In this way, the quality of the first algorithm is refined or improved for future predictions. Depending on the deviation between the actual position of the eye and the further prediction, the second algorithm for determining the further prediction or the further prediction data can be changed, i.e. trained, refined or adapted. In this way, the quality of the second algorithm is refined or improved for future further predictions.

[0039] A third aspect of the present invention relates to a control device, which is configured to perform one of the above methods. The above advantages are generated. For example, the control device can be configured as a control chip, a control device or an application program ("application"). Preferably, the control device may include a processor device and / or a data memory. The processor device understands an apparatus or an apparatus component for electronic data processing. For example, the processor device may include at least one microcontroller and / or at least one microprocessor. Preferably, the program code for performing the method according to the present invention can be stored on an optional data memory. Then, the program code can be suitable for causing the control device to perform one of the above embodiments of one or both methods according to the present invention when executed by the processor device.

[0040] A fourth aspect of the invention relates to a therapeutic device having at least one ophthalmic surgical laser for separating tissue predefined by control data, in particular a corneal volume with a predetermined interface of a human or animal eye, by photodisruption and / or photoablation, and at least one control device for the laser or lasers, which is formed to carry out the steps of the method according to the first and / or second aspect of the invention. The therapeutic device according to the invention allows to reliably reduce or even avoid the disadvantages that occur when using conventional ablative and / or photodisruptive therapeutic devices.

[0041] In another advantageous configuration 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 corresponding pulse duration between 1 fs and 1 ns, preferably between 10 fs and 10 ps, ​​with a repetition frequency greater than 10 kilohertz (kHz), preferably between 100 kHz and 100 megahertz (MHz). Such femtosecond lasers are particularly suitable for removing tissue within the cornea. The use of photodisruption and / or photoablation lasers in the method according to the invention also has the advantage that no irradiation of the cornea is necessary in the wavelength range below 300 nm. In laser technology, this range is referred to as "deep ultraviolet". As a result, unintentional damage to the cornea caused by these very short wavelength and high-energy beams is advantageously avoided. Photodisruption lasers of the type used here typically input 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 individual laser pulses required for optical penetration can be narrowly limited spatially, thereby allowing a high cutting accuracy in the interface generation. In particular, the range between 700 nm and 780 nm may also be selected as the wavelength range.

[0042] In another advantageous embodiment of the treatment device according to the invention, the control device can include at least one storage device for at least temporarily storing at least one control data set, wherein one or more data sets include control data for positioning and / or focusing individual laser pulses in the cornea and can include at least one beam device for beam guiding and / or beam shaping and / or beam deflection and / or beam focusing of the laser beam of the laser. The control data set includes control data determined in the method for removing tissue.

[0043] Further features and advantages thereof can be derived from the description of the first inventive aspect, wherein advantageous configurations of each inventive aspect should be considered as advantageous configurations of the other inventive aspect, respectively.

[0044] A fifth aspect of the invention relates to a computer program comprising instructions for causing a therapeutic apparatus according to the fourth aspect of the invention to perform method steps according to the first aspect of the invention and / or method steps according to the second aspect of the invention.

[0045] A sixth aspect of the present invention relates to a computer readable medium on which a computer program according to the fifth inventive aspect is stored. Other features and advantages thereof can be derived from the description of the first to fifth inventive aspects, wherein an advantageous construction of each inventive aspect should be considered as an advantageous construction of another inventive aspect, respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Further features are evident from the claims, the drawings and the description of the drawings. The features and feature combinations mentioned above in the description of the drawings and the features and / or feature combinations mentioned below in the description of the drawings and / or the features and feature combinations shown only in the drawings can be used not only in the respectively specified combination but also in other combinations without departing from the scope of the invention. Therefore, embodiments which are not explicitly shown and described in the drawings are also to be considered to be encompassed and disclosed by the present invention, but are produced and generated by feature combinations separate from the described embodiments. Embodiments and feature combinations are also to be considered to be disclosed and therefore do not include all features of the originally formulated independent claims. Furthermore, embodiments and feature combinations which go beyond or deviate from the feature combinations set out in relation to the claims are to be considered to be disclosed, in particular by the embodiments set out above. It is shown:

[0047] Figure 1 is a schematic diagram of a therapeutic apparatus according to the present invention according to an exemplary embodiment;

[0048] Figure 2 is a flow chart of a method according to the present invention according to an exemplary embodiment; and

[0049] Figure 3 is a flow chart of further steps of the method according to the invention according to an exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0050] Figure 1 A schematic diagram of a treatment device 10 with an ophthalmic surgical laser 12 for removing tissue 14 of a human or animal eye 16 by photodisruption and / or photoablation is shown. For example, the tissue 14 may represent a lenticule or also a volumetric body, which may be separated from the cornea 16 of the eye by the ophthalmic surgical laser 12 to correct a visual disorder. The geometry of the tissue 14 to be removed, and thus the tissue removal geometry 14, may be provided by a control device 18, in particular in the form of control data, so that the laser 12 emits pulsed laser pulses into the cornea 16 of the eye in a pattern predefined by the control data to remove the tissue 14. Alternatively, the control device 18 may be a control device 18 external to the treatment device 10.

[0051] also, Figure 1 It is shown that the laser beam 19 generated by the laser 12 can be deflected by a beam deflection device 22, ie a beam deflection apparatus, such as a rotary scanner, towards the eye 16 to remove tissue 14. The beam deflection apparatus 22 can also be controlled by the control device 18 to remove tissue 14.

[0052] Preferably, the illustrated laser 12 may be a photodestructive and / or photoablative laser, which is configured to emit laser pulses in a wavelength range between 300 nm and 1400 nm, preferably between 700 nm and 1200 nm, with a corresponding pulse duration between 1 femtosecond and 1 nanosecond, preferably between 10 femtoseconds and 10 picoseconds, and a repetition frequency greater than 10 kHz, preferably between 100 kHz and 100 MHz. Optionally, the control device 18 further comprises a storage device (not shown) for at least temporarily storing at least one control data set, wherein one or more control data sets include control data for positioning and / or focusing individual laser pulses in the cornea. The position data of the individual laser pulses are determined based at least on the following method.

[0053] Figure 2 A flow chart of an exemplary embodiment of a method for controlling an ophthalmic surgical laser 12 of a treatment device 10 according to the position and / or orientation of a target during treatment of a cornea of ​​a human or animal eye 16 is shown. Therein, the laser beam of the laser 12 or the laser pulses of the laser 12 meet the target point of the eye 16 as accurately as possible. Since the eye 16 is often in motion and cannot be completely "fixed", the movement of the eye 16 is captured and taken into account, so that the beam guidance of the laser beam 19 of the laser 12 or the laser pulses of the laser 12 is compensated. Therefore, the method is used to adjust the predetermined laser pulses relative to their respective position or orientation, thereby compensating for the movement of the eye 16.

[0054] In order to determine the movement or "tracking" of the eye 16 and / or the target point, the treatment device 10 comprises at least one camera 20. The control device 18 is formed to evaluate images of the eye 16. The camera 20 can be formed to capture these images of the eye 16 and transmit them to the control device 18. The control device 18 can be formed to receive images of the eye 16 from the camera 20. In particular, the image from the camera 20 is a video signal, consisting of a plurality of consecutive frames. Depending on the image capture rate of the camera 20, for example 1200 Hz or 1200 fps (frames per second), the latency of the camera 20 can be slightly less than one millisecond.

[0055] The control device 18 may include an image processing unit 22. The image of the eye 16 may be processed and / or evaluated by the image processing unit 22, respectively. In particular, the position of the eye 16 and / or the target point may be determined by the image processing unit 22, respectively. The image processing unit 22 may include, for example, a microprocessor, a digital signal processor, an FPGA, etc. In this case, a delay of about 1 ms, for example a delay of 0.9 ms, may occur. The processed image may further be output to an output unit 32, for example a screen.

[0056] By means of the main control unit 24 of the control device 18, the result of capturing the position and / or movement of the eye 16 can be associated with a predetermined laser pulse from the pulse list 26. Here, it can be determined, corresponding to which position specification the laser 12 or the beam device 17 must be adjusted to direct the laser pulse assigned by the pulse list 26 to the target position. The coordinates of the position specification for the laser 12 can consist of the coordinates of the corresponding laser pulse and an offset, wherein the coordinates can be assigned by the pulse list 26 and / or the offset comes from the position and / or movement of the eye 16 or the target point. Therein, the offset is used to compensate for the movement of the eye. Here, the delay is, for example, about 90 μs. Corresponding to the position specification, the laser 12 or the beam device 17 can then be adjusted or directed. This can be achieved by the actuation unit 28. The actuation delay of the actuation unit 28 is exemplarily about 100 ns. For example, the actuation unit 28 can be provided by an amplifier for actuating the beam device 17. The actuation unit 28 can, for example, actuate the adjustment unit 30 or provide a signal, current or voltage to the adjustment unit 30. The adjustment unit 30 is particularly formed for mechanically orienting the light beam device 17 in response to an actuation of the actuation unit 28. The delay for adjusting or orienting the light beam device 17 may be, for example, up to 1 ms, for example, depending on the adjustment path in the orientation. The main control unit 24 may, for example, comprise a microprocessor, a digital signal processor, an FPGA or the like.

[0057] The above delay is compensated by the following steps of the implementation scheme of the method:

[0058] In step S1, respective pictures of the eye are captured at least at a first point in time and at a later second point in time. This can be achieved by the camera 20 as described above. Alternatively or additionally, capturing the images can be performed by the control unit 18, as it receives the images from the camera 20. For example, the camera 20 captures at least a first picture at a first point in time and a second picture at a later second point in time. Of course, it is also possible to capture multiple frames of the video signal captured one after another and use them for further methods.

[0059] In step S2, motion information about the movement of the eye and / or target point is determined based on the corresponding picture. Specifically, this can be performed by the control unit 18. Specifically, the motion information is determined by the image processing unit 22. At this point, the image processing unit 22 can specifically evaluate the first picture and the second picture. For example, the relative movement of the eye and / or target point between the first picture and the second picture can be determined as motion information. In the case of multiple pictures, the corresponding relative movement between the pictures can be determined as part of the motion information. For example, the corresponding relative movement between two images captured at adjacent time points can be captured or determined. The motion information or relative movement can be determined and indicated in the form of corresponding vectors (in the case of translational movement) and / or angles (in the case of rotational movement), respectively, for example. Among them, the motion information of different degrees of freedom can be determined jointly and / or independently of each other, such as three independent translational degrees of freedom and / or three independent rotational degrees of freedom.

[0060] In step S3, prediction data is determined, which includes a prediction of the future position and / or orientation of the target point at a later point in time. The prediction data is determined based on the motion information. Therein, the later point in time is preferably separated in time from the second point in time by a period of time, the duration of which is derived at least from the total delay of the image evaluation and the adjustment of the laser 12 or the light beam device 17. Therefore, based on the motion information, a prediction of the future position and / or orientation of the target point at a later point in time can be determined. The prediction can be determined as part of the prediction data. Therein, the later point in time is separated in time from the second point in time by a period of time, the duration of which is derived at least from the total delay of the image evaluation and the adjustment of the laser 12 or the light beam device 17. For example, the total delay is obtained by the added delay of steps S1, S2, S3, S4 and S5. Therefore, the total delay can be obtained by adding the corresponding delays of the camera 20 (about 1 ms), the image processing unit 22 (about 0.9 ms), the main control unit 24 (about 90 μs), the actuation unit 28 (about 100 ns) and the orientation of the beam device 17 (about 1 ms). The total delay can be preset by a preset average value. Alternatively, the corresponding delays can be preset by the corresponding average values. Step S3 can be performed, for example, by the image processing unit 22.

[0061] In step S4, the position specification of the laser pulse is determined at least based on the prediction data. Thus, the prediction of the future position and / or orientation of the target point is used to determine the position specification of the laser pulse. For example, the position specification of the laser pulse can be fixed in a coordinate system aligned with the eye 16 or the cornea 14 by the pulse list 26. In this embodiment, the movement of the eye 16 can be a relative movement between the coordinate system aligned with the eye 16 and the world coordinate system or the coordinate system aligned with the treatment device 10. Thus, the position specification of the laser pulse can be determined, for example, taking into account the prediction data, in particular the future position of the eye 16 and / or the target point, in the world coordinate system or the coordinate system aligned with the treatment device.

[0062] In step S5, the laser 12 is adjusted according to the position specification. Thus, the laser 12 can be adjusted and / or oriented according to the position specification. The adjustment or orientation of the laser 12 is currently achieved by orienting or adjusting the beam device 17 for beam guidance and / or beam shaping and / or beam deflection and / or beam focusing of the laser beam 19 of the laser 12. For example, by actuating the beam device 17 accordingly according to the position specification, future laser pulses can be directed to the target point.

[0063] In step S6, further motion information is determined based on at least one third picture. To this end, in particular, a third picture of the eye 16 is captured at a third time point, wherein the third time point is temporally after the second time point, but before the later time point. The third picture can be a frame of the video signal of the camera 20 after the second picture. In step S6, the prediction as part of the prediction data is checked at least in particular based on the third picture. In other words, it can be provided that a third picture of the eye is captured at a third time point. Wherein the third time point is temporally between the second time point and the later time point. Therefore, based on the third picture, the validity and quality of the prediction as part of the prediction data can be checked respectively. This is based on the idea that at the third time point when the third picture is captured, due to the delay in adjusting the laser, it can no longer be oriented or adjusted based on the position and / or orientation of the target point derived from the third picture. Therefore, despite the presence of a newer picture, namely the third picture, the laser still corresponds to the prediction or the prediction data is adjusted to the position specification derived from it, as described above. Wherein the third time point is in particular between the second time point and the later time point, so that the image evaluation of the third picture exists or is determined before the triggering of the laser pulse. Therefore, a laser that was previously adjusted or directed based on a prediction derived from the second picture at the second point in time can no longer be adjusted relative to the position specification, but enabling or disabling laser pulses is possible depending on the fact how good the prediction was proven to be within the scope of the inspection based on the third picture.

[0064] As part of step S6, it is currently provided that further motion information is determined at least based on the third picture. In a following step S7, further prediction data are determined, at least based on the third picture or based on the further motion information, the further prediction data comprising a further prediction of the future position and / or orientation of the target point at a later time point. The prediction or prediction data may be based on the second picture which is the latest picture at the respective prediction time point. The further prediction data or further prediction may be based on the latest picture at the third time point, i.e. the third picture. Therefore, the further prediction data may more accurately predict the position and / or orientation of the target point at a later time point, because the time period to be spanned by the prediction is shorter than the prediction data based on the prediction data of the second picture at the second time point.

[0065] Depending on the result of the check prediction, based on the further prediction data, the laser pulses can be enabled for the position specification previously adjusted based on the prediction data (step 8.1), or the laser 12 can be commanded to be newly adjusted to the updated position specification (step 8.2). The check of the prediction or the prediction data can be realized based on the further prediction data or the further prediction. In the check, for example, it can be determined to what extent the prediction and the further prediction agree or deviate from each other. In particular, for example, if the deviation between the prediction and the further prediction or between the prediction data and the further prediction data is less than a predetermined threshold, the laser pulses can be enabled accurately, for example. Similarly, if the previously mentioned deviation is greater than a predetermined threshold, the laser 12 or the beam device 17 can be commanded to be newly adjusted to the updated position specification. As already described above, the position specification is derived from the prediction of the position and / or orientation of the target point at a later point in time. If the above-mentioned deviation exceeds the threshold, an updated position specification can be determined. In addition, the laser can be adjusted or oriented according to the updated position specification. Here, it is necessary to reiterate that the second picture can be the latest picture for adjusting the laser for a laser pulse, which adjustment of the laser for a laser pulse will be realized at a later point in time, because there is a delay both in adjusting the laser 12 and in performing the image evaluation. Based on further prediction data or a further prediction, it is no longer possible to adjust the laser 12 for the laser pulse that will occur at a later point in time due to the total delay. However, since only the delay of the image evaluation is important for checking the prediction based on the further prediction, a check can still be performed before the later point in time when the laser is triggered.

[0066] Figure 3 Optional method steps of the method are further shown in another flow chart. They can be Figure 2 The method is then executed.

[0067] Step S9 provides for capturing a fourth picture of the eye 16 at least approximately at the later time point. Step S10 provides for determining the actual position and / or orientation of the target point at the later time point based on the fourth picture. Step S11 provides for comparing the actual position of the eye 16 at the later time point with the prediction as part of the prediction data and / or the further prediction as part of the further prediction data. Step S12.1 provides for changing the first algorithm for determining the prediction data depending on the comparison result. Step S12.2 provides for changing the second algorithm for determining the further prediction data depending on the comparison result.

[0068] If the individual pictures, such as the first picture, the second picture, the third picture and / or the fourth picture, are part of a video signal, then exactly that frame of the video signal can be selected as the fourth picture, and the capture time of the fourth picture is closest to the later time point. Therefore, the fourth picture is related to the eye approximately at the later time point. In other words, the fourth picture images the eye approximately at the later time point. Therefore, the position and / or orientation that the target point actually has at the later time point can be determined based on the fourth picture. By comparing the actual position of the eye at the later time point with the prediction of the eye position at the later time point (which is part of the prediction data), it can be determined or confirmed how good the prediction is. For example, the quality of the prediction can be evaluated and quantified by a value, which indicates the deviation between the actual position and the predicted position. By comparing the actual position of the eye at the third time point with the further prediction of the eye position at the later time point (which is part of the further prediction data), it can be determined or confirmed how good the further prediction is. For example, the quality of the further prediction can be evaluated and quantified by a value, which indicates the deviation between the actual position and the predicted position.

[0069] Depending on the deviation between the actual position of the eye and the prediction, the first algorithm for determining the prediction or the prediction data can be changed, i.e. trained, refined or adapted. In this way, the quality of the first algorithm is refined or improved for future predictions. Depending on the deviation between the actual position of the eye and the further prediction, the second algorithm for determining the further prediction or the further prediction data can be changed, i.e. trained, refined or adapted. In this way, the quality of the second algorithm is refined or improved for future further predictions.

[0070] Reference character list:

[0071] 10 Treatment Equipment

[0072] 12 Laser

[0073] 14 Organization

[0074] 16 Eyes

[0075] 17 Beam deflection device

[0076] 18 Control Devices

[0077] 19 Laser Beam

[0078] 20 Camera

[0079] 22 Image Processing Unit

[0080] 24 Main control unit

[0081] 26 Pulse List

[0082] 28 Actuation unit

[0083] 30 Adjustment unit

[0084] 32 output units

[0085] S1 to 8.2 Methods and Steps

[0086] S9 to S12.2 Method steps

Claims

1. A computer program product comprising instructions for controlling an ophthalmic surgical laser (12) of a treatment device (10) during corneal treatment of a human or animal eye (16) according to the position and / or orientation of a target point of the eye (16), wherein the computer program causes the treatment device (10) to perform the following steps: - capturing (S1) corresponding pictures of the eye (16) at least at a first point in time and at a later second point in time, - determining (S2) movement information about the movement of the eye (16) and / or the target point based on the corresponding pictures, and - determining (S3) prediction data based on the motion information, the prediction data comprising a prediction of a future position and / or orientation of the target point at a later point in time, wherein the later point in time is separated in time from the second point in time by a period of time, the duration of which is derived at least from a delay of the image evaluation, - determining (S4) a position specification of the laser pulse at least based on said prediction data, and - adjusting (S5) the laser according to the position specification; wherein a third picture of the eye (16) is captured at a third point in time, wherein the third point in time is temporally subsequent to the second point in time but prior to the later point in time, wherein a prediction as part of the prediction data is checked based on at least the third picture; Depending on the predicted check result, laser pulses for the position specification previously adjusted based on the predicted data are enabled (S8.1) or a new adjustment of the laser to an updated position specification is commanded (S8.2).

2. The computer program product according to claim 1, It is characterized in that During the determination (S3) of the prediction data, the later time point is separated in time by at most the first time point.

3. The computer program product according to claim 1, It is characterized in that The accelerations and / or velocities along a plurality of degrees of freedom are captured independently of one another and / or are evaluated independently of one another when determining ( S3 ) the prediction data.

4. The computer program product according to claim 1, It is characterized in that The later point in time is temporally separated from the second point in time by a total time period, wherein the duration of the total time period is derived at least from a delay of the image evaluation and a delay for adjusting the laser.

5. The computer program product according to claim 1, It is characterized in that - determining (S6) further motion information based on at least said third picture, and - based on said further motion information, determining (S7) further prediction data, said further prediction data comprising a further prediction of a future position and / or orientation of the target point at said later point in time.

6. The computer program product according to claim 5, It is characterized in that - capturing at least a fourth picture of said eye (16) at said later point in time, - determining the actual position and / or orientation of the target point at said later point in time based on said fourth picture, and - comparing the actual position of the eye (16) at the later point in time with the prediction as part of the prediction data and / or with the further prediction as part of the further prediction data, - depending on the result of the respective comparison, changing the first algorithm for determining the prediction data and / or the second algorithm for determining the further prediction data.

7. A control device (18) designed to cause a treatment device (10) to execute a computer program product according to claim 1.

8. Treatment device (10) having at least one ophthalmic surgical laser (12) for orthokeratology of the cornea by photodisruption and / or photoablation, and having a control device (18) according to claim 7.

9. The therapeutic device (10) according to claim 8, Features The laser (12) is designed to emit laser pulses in the wavelength range between 300 nm and 1400 nm with a respective pulse duration between 1 fs and 1 ns at a repetition rate greater than 10 kHz.

10. The therapeutic device (10) according to claim 8, It is characterized in that The control device (18) - comprising at least one storage device for at least temporarily storing at least one control data set, wherein one or more control data sets comprise control data for positioning and / or focusing a single laser pulse in the cornea; and - comprises at least one beam device (17) for beam guiding and / or beam shaping and / or beam deflecting and / or beam focusing a laser beam (19) of the laser.

11. Computer readable medium having stored thereon the computer program product according to claim 1.

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