Method for controlling a treatment device, treatment device, computer program and computer-readable medium

Abstract

The invention relates to a method for controlling a treatment device (10) with an ophthalmic laser (12) for treating a human or animal eye (16), a control device (18) and a fixation device (30) for fixing the eye (16) for treatment by means of negative pressure, wherein during the treatment a course of a negative pressure signal is determined by the control device (18), wherein the control device (18) checks whether a predetermined fixation instability criterion is met for the negative pressure signal, and wherein if the fixation instability criterion is present, the control device (18) sends a first control signal to the treatment device (10) to rebuild negative pressure, and if a further check of the negative pressure signal shows that the fixation instability criterion is no longer met, a second control signal is sent to the treatment device (10).

Description

[0001] The invention relates to a method for controlling a treatment device, a treatment device, a computer program and a computer-readable medium.

[0002] Treatment devices using an ophthalmic (eye surgery) laser for treating refractive errors in a human or animal eye are known in the prior art. When treating the eye with the treatment device, it is important that the eye is not moved during treatment so that the planned incisions and / or changes in the eye are made at the predetermined positions. To achieve this, fixation devices are known that hold the eye in position during treatment. For example, there are mechanical fixation devices, in particular contact elements that are pressed onto the eye, or suction devices, such as suction rings, that fix the eye using negative pressure. However, it can happen that fixation is lost during treatment.If loss of fixation occurs, there is a risk for the patient that partially advanced treatment may or may not be discontinued, and a salvage technique may be required (see, for example, Chung B., Kang DSY, Kim JH, Arba-Mosquera S., Jean SK, Jun I., Kim EK, Seo KY, Kim KY, Kim TI, “Clinical outcomes of immediate transepithelial photorefractive keratectomy after suction loss during small-incision lenticule extraction”. J. Cataract Refract Surg. 2020 May; 46(5):756-761).

[0003] The object of the present invention is therefore to improve a fixation process for a treatment of an eye and to avoid a loss of fixation of the eye during the treatment.

[0004] This object is achieved by the method according to the invention, the devices according to the invention, the computer program according to the invention, and the computer-readable medium according to the invention. Advantageous developments of the invention are disclosed in the dependent patent claims, in the following description, and in the accompanying drawings, wherein advantageous embodiments of the method are to be regarded as advantageous embodiments of the treatment device, the control device, the computer program, and the computer-readable medium, and vice versa.

[0005] The invention is based on the idea that a pressure curve in the fixation device can be monitored, which reflects the pressure curve in a volume between the fixation device and the eye, by which the eye is held against the fixation device. If the negative pressure cannot be maintained and the pressure curve exceeds a first threshold, this may be an indication that the fixation is insufficient. In this case, an attempt can be made to improve the fixation or to interrupt the treatment and resume it when the negative pressure is sufficient.

[0006] In a first embodiment, the invention comprises a method for controlling a treatment device with an ophthalmic laser for treating a human or animal eye, a control device and a fixation device for fixating the eye for the treatment by means of negative pressure, wherein during the treatment a profile of a negative pressure signal is determined by the control device, the control device checks whether a predetermined fixation instability criterion is met for the negative pressure signal, and if the fixation instability criterion is met, the control device sends a first control signal to the treatment device in order to build up a negative pressure again and, if a further check of the negative pressure signal shows that the fixation instability criterion is no longer met, a second control signal is sent to the treatment device.

[0007] It should be noted that the pressure in the fixing device is lower than an ambient pressure P Umg (for example, 1013.25 hectopascals) and is provided by a pump located in the treatment device or externally. The pressure in the fixation device can be referred to as positive pressure P Fix which is smaller than the ambient pressure P Umg or it can be described as negative pressure P UD which is a differential pressure obtained by subtracting the pressure in the fixing device P Fix from the ambient pressure P Umg can be specified: P UD = P Umg - P Fix However, for the purposes of the application, the negative pressure should be given as an absolute value, ie P UD = | P Umg - P Fix |, so that an increase in the negative pressure P UD fixation of the eye is improved.

[0008] In other words, the invention comprises a method for controlling an ophthalmic surgical treatment device with an ophthalmic surgical laser, wherein the laser is used to treat the human or animal eye. The treatment device further comprises a control device and a fixation device. The eye can be fixed for treatment by means of the fixation device. A negative pressure is applied to fix the eye to the fixation device. This can reduce eye movement, and a distance of the eye from the treatment device can be set to a predetermined value. The negative pressure can be supplied to the fixation device by a pump device integrated into the treatment device or external to it, i.e., a gas present between the eye and the fixation device can be pumped out towards the pump.In this case, the course of a negative pressure signal, i.e. a temporal course of a negative pressure, can be determined or measured, and the control device can evaluate the measured signal or the course of the negative pressure signal. In this case, the control device can check whether a predetermined fixation instability criterion is met, i.e. the control device checks whether the criterion is met and can use the criterion to estimate whether the fixation is or is becoming unstable. If it is determined that the fixation instability criterion is met or exists, the control device can send a first control signal to the treatment device, for example to build up a negative pressure again. If it is determined that the fixation instability criterion no longer exists, a second control signal can be sent to the treatment device.

[0009] The method can be carried out by a control device included in the treatment device or, for example, by an external control device. The treatment device can comprise the control device and the fixing device, or the control device and the fixing device can be provided separately from the treatment device.

[0010] As described above, the negative pressure signal is a time-dependent process. Monitoring of the negative pressure signal can begin before treatment and can continue even during an interruption of laser treatment.

[0011] The fixation instability criterion also allows for an assessment of the quality of fixation during treatment. The criterion should be selected so that it is met if the fixation becomes or is unstable.

[0012] The first control signal enables the treatment device, for example, to initiate further pumping by increasing the pump power, opening or partially opening a throttle valve, and / or switching on a second pump to increase the negative pressure. Furthermore, based on the first control signal, for example, laser irradiation can be interrupted, a warning message regarding a pressure can be issued, and / or a user can be prompted to provide confirmation. The second control signal makes it possible, for example, to reduce the pump power, close or partially close a throttle valve to reduce the negative pressure, switch off the second pump, continue the treatment, and / or delete a warning to the user.

[0013] By means of the invention, it can be achieved that laser irradiation is not performed by the treatment device if the fixation instability criterion is met. This means that laser irradiation is only performed if the stability of the fixation is sufficient for safe irradiation, or is estimated to be sufficient and the fixation instability criterion is not met.

[0014] The invention includes further embodiments or further developments and modifications which result in additional advantages.

[0015] According to a further development, the method can provide that the treatment of the eye comprises the treatment of a visual impairment of the eye. For example, a visual impairment can be treated by superficially ablating an epithelial layer and / or a cornea of ​​the eye, or, for example, a piece of tissue (lenticule) within the stroma of the eye can be excised, which can subsequently be manually removed by a user of the treatment device. Furthermore, further methods for cauterizing or for removing irregularities of the eye are included. The invention enables the respective treatments to be carried out safely and prevents the treatment from being carried out in the event of loss or imminent loss of fixation. This improves the safety of the treatment.

[0016] According to a further development, the method can provide that the first control signal serves to interrupt the irradiation with the laser, and the second control signal can serve to continue the irradiation with the laser.

[0017] In other words, the treatment device can interrupt the laser irradiation if the fixation instability criterion is met and the treatment device receives the first control signal from the control device. Furthermore, the treatment device can automatically continue the treatment if the fixation instability criterion is no longer met and the treatment device receives the second control signal. This has the advantage that the treatment device can respond automatically and flexibly to a negative pressure curve from which it can be estimated that the fixation is inadequate.

[0018] According to a further development, the method can provide that the renewed build-up of the negative pressure is only continued after an optical check of an alignment of the eye or after a realignment of the eye with respect to the fixation device.

[0019] In other words, the method can provide that irradiation or laser treatment of the eye is only continued after a user of the treatment device has checked the eye or realigned the eye in the fixation device. This allows irradiation to be stopped or not continued with a poorly or insufficiently fixated eye.

[0020] According to a further development, the method can provide that the fixation instability criterion is met if the negative pressure signal during the treatment exceeds or falls below a predetermined limit value for at least a predetermined time period t1, if a change in the negative pressure signal exceeds or falls below a predetermined second limit value for at least a predetermined time period t1, or if a change in the negative pressure signal has a predetermined sign for at least a predetermined time period t1.

[0021] In other words, based on the profile of the negative pressure signal, the control device can estimate or determine that the fixation instability criterion is met if the negative pressure between the eye and the fixation device is less than or greater than a predetermined limit, i.e., the negative pressure is insufficient, and this condition persists for a predetermined period of time t1 or longer. Furthermore, it is possible for a change in the negative pressure signal to be less than or greater than a predetermined second limit for at least a predetermined period of time t1, and the control device determines, based thereon, that the fixation instability criterion is met.Furthermore, if a change in the negative pressure signal for a predetermined time period t1 has a predetermined sign, this may be an indication that, for example, an increasing amount of air is flowing in between the eye and the fixation device and thus fixation is insufficient, or that, for example, a suction channel of the fixation device is blocked, a negative pressure increases sharply and yet fixation is insufficient.

[0022] The specified limit is a value that the negative pressure must not exceed or fall below, i.e., a maximum or minimum tolerable pressure. Furthermore, the limit can restrict the amount of change that must not be exceeded or undercut. Furthermore, the criterion can specify that a change does not occur continuously in a specific direction, i.e., in the direction of increasing or decreasing pressure. This has the advantage that the treatment device can react automatically and flexibly to a negative pressure curve, from which it can be assessed whether the fixation is inadequate.

[0023] According to a further development, the method can provide that the fixation device comprises a plurality of suction channels that provide respective negative pressure signals, wherein the fixation instability criterion is met if at least one of the negative pressure signals exceeds or falls below a predetermined limit value for at least a predetermined time period t1. In other words, the fixation device can have a plurality of suction channels through which a gas present between the fixation device and the eye can be pumped out, and these or some of these suction channels can provide negative pressure signals, and the control device can be configured to determine that the fixation instability criterion is met if at least one of the negative pressure signals exceeds or falls below the predetermined limit value for at least the predetermined time period t1. These suction channels can be distributed around the eye, and the eye is suctioned and fixated via the suction channels.This has the advantage that a blockage of an intake channel does not jeopardize the fixation by the fixation device. Furthermore, redundant provision of vacuum signals allows for a better assessment of the fixation.

[0024] According to a further development, the method can provide that the vacuum signal comprises vacuum values ​​of a vacuum in a vacuum line through which the vacuum is supplied to the fixation device. In other words, a plurality of signal transmitters can be attached to a vacuum line from the pump to the fixation device, which signal transmitters detect a vacuum signal or a curve of the vacuum signal, wherein the vacuum is supplied to the fixation device through the vacuum line. It is obvious that the closer a signal transmitter is attached to the fixation device, the more closely the detected vacuum corresponds to the vacuum between the eye and the fixation device. By means of the plurality of signal transmitters, it is possible, for example, to detect or determine a gas flow that flows between the fixation device and the pump.This allows for even better detection of negative pressure and thus an even better determination of whether fixation of the eye to the fixation device is sufficient for laser irradiation or not.

[0025] According to a further development, the method can provide that the treatment device and / or the fixation device comprises an image recording device or a camera, wherein the fixation instability criterion is checked using the image recording device. In other words, a camera can be provided that can capture the fixation device and the eye, and the fixation instability criterion can be checked using the images captured by the image recording device. This has the advantage that optical detection of the fixation instability criterion can be provided.

[0026] According to a further development, the method can provide that the fixation instability criterion is met if it is determined by the image recording device that a movement of the eye during the treatment exceeds a predetermined limit. In other words, if it is determined by the camera that an eye movement becomes greater or stronger than a limit, in particular during a predetermined time t1 or longer, the control device can determine that the fixation instability criterion is met. For example, a time course can be recorded using a feature of the eye, for example the pupil, a limbus, a vertex, features of an iris of the eye, etc., and a measure of an eye movement can be derived from a movement of such a feature over time. In the case of insufficient fixation, an eye movement can exceed a predetermined limit.Furthermore, the control device can also be configured to determine that the fixation instability criterion is met if the eye continuously moves in one direction, if the eye moves faster than a certain distance per time interval during a time interval, or if a position of the feature along the laser beam direction moves away from or toward the fixation device. In this case, the control device can determine that the fixation instability criterion is met.

[0027] According to a further development, the method provides that the fixation device has a suction device, in particular a suction ring or suction-capable ring segments, by means of which the eye is fixed by means of the negative pressure, and the fixation instability criterion is met if a detachment of the fixation device from the eye is detected.

[0028] In other words, a suction device can be provided that generates a negative pressure by means of a pump, wherein the negative pressure sucks a surface of the eye via the suction ring or via suction-capable ring segments. Thus, the eye is fixed at the contact points of the suction ring or the absorbent ring segments. Detachment of the fixation device from the eye can be detected, for example, by a change in the eye's focus, the ingress of air, detachment of the eye surface from the fixation device, and / or significant movement of the eye. This development has the advantage that detection of a loss of fixation of the eye is possible more flexibly.

[0029] According to a further development, the method can provide that the image recording device additionally detects the transition from the suction device to the eye, and the fixation instability criterion is met if it is determined by means of the image recording device that bubble formation occurs at the transition during the treatment. In other words, the control device can determine that the fixation instability criterion is met if, for example, bubble formation occurs at the transition from the suction device to the eye, which indicates the penetration of air through the gap between the eye and the fixation device. Bubble formation here means the "bubbling" of a separating film (between the eye and the fixation device) in the vicinity of the suction elements. This means that the separating film is being sucked in, and penetrating air bubbles will generate.This may indicate a detachment of the fixation device from the eye, so that when this feature occurs, the control device can determine that the fixation instability criterion is met. It should be noted that this blistering must be distinguished from the formation of microbubbles due to photodisruption or photoablation, for example, when creating cut surfaces in the cornea.

[0030] According to a further development, the method can provide that the image recording device additionally detects the transition from the suction device to the eye, and the fixation instability criterion is met if the image recording device determines that parts of the conjunctiva of the eye become visible within the fixation device during the treatment. In other words, the appearance of a conjunctiva of the eye within the fixation device can indicate a detachment of the fixation device from the eye, and the control device can determine that the fixation instability criterion is met if parts of the conjunctiva of the eye are detected within the fixation device when detected by the image recording device. A conjunctiva, for example, can be easily identified based on its different color. This enables an even more reliable determination of whether the fixation is sufficient.

[0031] According to a further development, the method can provide that, if the fixation instability criterion is met, a warning message is issued to a user of the treatment device. In other words, the treatment device can, for example, issue a warning message on a screen of the treatment device based on the first control signal from the control unit, or can, for example, emit a warning tone indicating that the fixation instability criterion is met. This allows the user to assess the fixation and take appropriate countermeasures. Optionally, a fixation can be aborted, a fixation can be restarted, the treatment can be interrupted, or the application of negative pressure can be stopped.

[0032] The respective method may include at least one additional step that is executed precisely when a use case or application situation occurs that has not been explicitly described here. This step may, for example, include outputting an error message and / or a request for user feedback. Additionally or alternatively, it may be provided that a default setting and / or a predetermined initial state is set.

[0033] 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 embodied as an integrated circuit and / or microchip. Furthermore, the control device can comprise an (electronic) data memory or a memory unit. Program code which encodes the steps of the respective embodiment of the respective method can be stored on the data memory. The program code can comprise the control data for the respective laser.The program code can be executed by the computing unit, causing the control device to execute the respective embodiment. The control device can be embodied as a control chip or control unit. The control device can be comprised, for example, of a computer or computer network.

[0034] A further aspect of the invention relates to a treatment device comprising at least one ophthalmic or ophthalmic laser and a control device configured to perform the steps of at least one embodiment of one or both of the previously described methods. The respective laser can be configured to at least partially separate a predefined corneal volume with predefined interfaces of a human or animal eye by means of optical disruption, 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 cause a laser-induced refractive index change in the cornea and / or the lens of the eye.

[0035] A further aspect of the invention relates to a computer program. The computer program comprises instructions that, for example, form 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 a computer or a computer network, it is caused to execute the previously described method or at least one embodiment thereof.

[0036] A further aspect of the invention relates to a computer-readable medium (storage medium) on which the aforementioned computer program or its instructions are stored. To execute the computer program on a control device or computing apparatus, a computer or a computer network can access the computer-readable medium and read its contents. The storage medium is designed, for example, as a data memory, in particular at least partially as a volatile or non-volatile 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 can be present, for example, as source code of a programming language and / or as assembler and / or as binary code.

[0037] Further features and advantages of one of the described aspects of the invention may arise from the further development of another aspect of the invention. The features of the embodiments of the invention may thus be present in any combination with one another, unless explicitly described as mutually exclusive.

[0038] Additional features and advantages of the invention are described below with reference to the figures 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 with the features of the embodiments. This means that the features of the exemplary embodiments can supplement and / or replace the features of the embodiments, and vice versa. Thus, the invention also encompasses and discloses configurations that are not explicitly shown or explained in the figures, but which emerge and can be produced through separate combinations of features from the exemplary embodiments and / or embodiments.Thus, embodiments are also to be regarded as disclosed which do not have all the features of an originally formulated claim or which go beyond or deviate from the combinations of features set out in the references to the claims.

[0039] In the figures, identical or functionally equivalent elements are provided with the same reference numerals. The figures show: Fig. 1 a schematic representation of a treatment device; Fig. 2 schematically shows a time course of a negative pressure signal; Fig. 3 schematically shows a time course of a negative pressure signal; Fig. 4 a schematic plan view of an eye; Fig. 5 a schematic representation of a movement of a characteristic point of the eye; and Fig. 6 a schematic flow diagram.

[0040] Fig. 1 shows a schematic representation of a treatment device 10 with an ophthalmic laser 12 for treating a cornea 14 of an eye 16, in particular a cornea 14 (cornea) of the eye 16 by means of photodisruption and / or ablation and / or laser-induced refractive index change (LIRC).

[0041] In addition to the laser 12, the treatment device 10 can have a control device 18, which can be designed to control the laser 12 via control data, so that, for example, it can emit laser pulses in a predefined pattern for treating the eye 16 or the cornea 14 of the eye 16.

[0042] Furthermore, Fig. 1 that the laser beam 20 generated by the laser 12 can be deflected toward the eye 16 by means of a beam deflection device 22, such as a rotary scanner. The beam deflection device can also be controlled by the control device 18 to direct the laser beam 20 to predetermined positions in the eye 16, in particular in the cornea 14 of the eye 16.

[0043] The laser 12 can preferably be a photodisruptive and / or ablative laser configured to emit laser pulses in a wavelength range between 300 nm and 1400 nm, preferably between 700 nm and 1200 nm, with a respective pulse duration between 1 fs and 1 ns, preferably between 10 fs and 10 ps, ​​and a repetition frequency greater than 10 kHz, preferably between 100 kHz and 100 MHz. The control device 18 optionally also comprises a memory device (not shown) for at least temporarily storing at least one control data set, wherein the control data set(s) comprise control data for positioning and / or focusing individual laser pulses.

[0044] Furthermore, the treatment device 10 can have a fixation device 30 designed to fix the eye 16 to be treated at a predetermined position relative to the treatment device 10 for irradiation with the laser 12. The fixation device 30 can, for example, have a suction device 32, which can have a vacuum pump that can generate a vacuum on a suction ring or on suction-capable ring segments on one side of the fixation device 30, wherein the side is oriented towards the eye 16. In other words, the suction ring can be placed on the eye 16, and the suction device 32 can hold the eye 16 in a fixed position relative to the treatment device 10 by generating a negative pressure.The suction device 32 can be connected to the fixing device 30 by means of a vacuum line 34, and one or more signal transmitters 36 can be arranged on the fixing device 30, the vacuum line 34 or the suction device 32 in order to generate a vacuum signal in each case.

[0045] In order to align the eye 16 for the fixation device 30 and the beam path of the laser 12, and to fix it in the predetermined position, an image recording device 38 can be arranged in the treatment device 10, which preferably has at least one camera that can be arranged such that it can record or determine an alignment of the eye 16 below the fixation device 30. In particular, this image recording device 38 can be used to check whether a suction ring or a suction-capable ring segment is detaching from the eye 16, whether blistering is occurring between the fixation device 30 and the eye 16, and / or whether a conjunctiva of the eye 16 appears or becomes visible below the fixation device 30 or whether the conjunctiva is shifting.

[0046] Fig. Figure 2 shows a schematic diagram of a negative pressure signal over time. In the case of Fig. 2, it can be determined that the fixation instability criterion is present, in other words, that a negative pressure signal 56 deviates from a target value 50 and exceeds or falls below a limit value 52. At the time 54 in Fig. 2, for example, the negative pressure signal 56 increases to such an extent that it exceeds the predetermined limit value 52. This can be used, for example, to determine that the fixation instability criterion is present, i.e., that fixation of the eye 16 in the fixation device 30 is inadequate and safe irradiation with the laser 12 is not possible.

[0047] The limit value 52 can be configured as an upper and / or lower limit value 52, and the control device 18 can be configured to determine whether the limit value 52 has been exceeded or not reached by the negative pressure signal. For example, if air penetrates into the volume between the fixation device 30 and the eye 16, a negative pressure signal can drop, so that the limit value 52 is not reached. In this case, safe irradiation with the laser 12 can no longer be ensured, and the control device 18 can determine the presence of the fixation instability criterion. Furthermore, if an intake channel becomes blocked, a negative pressure signal can rise sharply, so that the limit value 52 is exceeded. In this case, too, safe irradiation with the laser 12 can no longer be ensured, and the control device 18 can determine the presence of the fixation instability criterion.

[0048] Fig. Figure 3 similarly schematically shows a time course of a negative pressure signal 56 in a similar case, in which at a time 58 a negative pressure signal 56 exceeds the limit value 52 and continues to exceed the limit value 52 for a period t1 or longer. If such a deviation occurs during treatment, it can be determined that the fixation instability criterion is present. As before, the limit value 52 can have an upper and a lower limit value 52.

[0049] Fig. 4 shows a schematic plan view of an eye 16, as it can be optically recorded, for example, by means of the image recording device 38. In Fig. 4, for example, a pupil 60 of an eye 16 can be recorded in order to identify a point 62, for example a center point of the eye 16, for example by means of the control device 18. A pupil 60 can be determined by the control device 18 using conventional methods, for example based on a difference in brightness in the recording, and thus it is possible to determine a characteristic point 62 of the eye 16. Alternatively or additionally, an iris 64 of the eye 16 can be detected, and by fitting a circle or ellipse 65 to it, a characteristic point or center point 62 can be determined. Furthermore, any other characteristic point of the eye 16 can be determined, for example, based on a difference in brightness.

[0050] A repeated recording by the image recording device 38 also makes it possible to determine a temporal course of an eye movement during the observation time interval and makes it possible to determine whether a movement of the characteristic point 62 exceeds a limit value 66 or not.

[0051] Fig. Figure 5 shows a schematic representation of a movement of the characteristic point 62 of the eye 16 during the observation time interval. In other words, Fig. 5 shows an example of a trajectory 68 of the characteristic point 62, ie a temporal progression of a position of the characteristic point 62 due to, for example, a Brownian motion or a tremor of the eye 16. In this example, a limit value 66 (here defined as the maximum deviation from a central point 63) is not exceeded, which indicates a maximum permissible movement of the characteristic point 62 and thus of the eye 16. It is also possible to specify a limit value 66, for example in the form of a polygonal limit value 66, which the trajectory 68 must not exceed. In the example of Fig. 5, the fixation instability criterion is not met, ie stability of the fixation of the eye is sufficient to safely carry out laser irradiation, since the trajectory 68 of the point 62 and thus an eye movement does not exceed the limit value 66.

[0052] Fig.6 shows a schematic flow diagram for a method for controlling a treatment device 10 with an ophthalmological laser 12 for treating a human or animal eye 16 and a fixation device 30 for fixing the eye 16 by means of negative pressure for the treatment or irradiation.

[0053] In a step S10, the treatment can be started by fixing the eye 16 using negative pressure by the fixation device 30, wherein a profile of a negative pressure signal 56 is determined during the treatment. Step S10 can include a waiting period until the negative pressure has sufficiently built up and the fixation is sufficiently stable. From step S10, the method proceeds to step S20.

[0054] In a step S20, a check is carried out to determine whether the fixation instability criterion is met. For example, the fixation instability criterion is met if the vacuum signal exceeds or falls below a predefined limit value 52 for at least a predefined period of time during the treatment, if a change in the vacuum signal exceeds or falls below a predefined limit value 52 for at least a predefined period of time, or if a change in the vacuum signal has a predefined sign for at least a predefined period of time. Furthermore, the fixation instability criterion can be met, for example, if at least one of vacuum signals from a plurality of intake channels exceeds or falls below a predefined limit value 52 for at least a predefined period of time. In addition, the fixation instability criterion can be measured using an image recording device 38 ora camera, for example by determining by means of the image recording device 38 that a movement of the eye 16, i.e. a trajectory 68 of a characteristic point 62 during the treatment, exceeds a predetermined limit value 52. Furthermore, the fixation instability criterion can be met, for example, if a detachment of the fixation device 30 from the eye 16 is determined by means of the image recording device 38, if it is determined by means of the image recording device 38 that blistering occurs at the transition during the treatment by means of the image recording device 38, or if it is determined by means of the image recording device 38 that parts of the conjunctiva of the eye 16 become visible within the fixation device 30 during the treatment.

[0055] If the fixation instability criterion is met in step S20 ("Y" in step S20), the method proceeds to step S30. Otherwise, or if the fixation instability criterion is not met ("N" in step S20), the method proceeds to step S60.

[0056] In step S30, the control device can send a first control signal to the treatment device 10. The first control signal can be used to interrupt the irradiation with the laser 12. The treatment device 10 can then, for example, interrupt the irradiation with the laser 12, initiate re-pumping of the vacuum, and / or open a throttle valve to rebuild a negative pressure, or take other measures to improve fixation. Furthermore, a warning message can be output to a user of the treatment device 10, for example. From step S30, the method proceeds to step S40.

[0057] In step S40, the control device can check again whether the fixation instability criterion is still met. If it is determined that the criterion is still met ("Y" in step S40), step S40 is repeated. It is also possible to wait a predetermined waiting time before the fixation instability criterion is checked again. Furthermore, the method can provide, for example, that an alignment of the eye 16 is checked, a new fixation is started, and / or that the fixation is checked again only after user confirmation. If the fixation instability criterion is not met ("N" in step S40), the method proceeds to step S50.

[0058] In step S50, the control device can send a second control signal to the treatment device 10, signaling that the fixation of the eye 16 is sufficient for continuing the treatment or irradiation with the laser 12. The second control signal can therefore serve to continue the irradiation with the laser 12. The treatment device 10 can then, for example, continue the irradiation with the laser 12, stop the re-pumping of the vacuum, reset a throttle valve to its original value, and / or take measures to continue the treatment. Furthermore, for example, a warning message to a user of the treatment device 10 can be deleted or removed. From step S50, the method returns to step S20. Optionally, the method can also proceed directly to step S60 (not shown).

[0059] In step S60, the control device can check whether the fixation, the irradiation, or the treatment has ended. For example, the fixation can be ended automatically after the irradiation has ended, or the user of the treatment device 10 can cause the fixation and thus the treatment to end. The fixation can be ended by stopping the supply of negative pressure to or the pumping out of the volume located between the fixation device 30 and the eye 16. Once the fixation or the treatment has ended, the method proceeds to step S70.

[0060] If the fixation or treatment has not yet ended ("N" in step S60), the method returns to step S20. After a possible additional waiting period, a further check for the presence of the fixation instability criterion can be performed.

[0061] The method is terminated in step S70. Alternatively or additionally, in step S70, the fixation by the fixation device 30 can be aborted, for example, by terminating the provision of a negative pressure through the negative pressure line 34, for example, by means of a controllable valve.

[0062] Overall, the examples show how a method for controlling a treatment device, a treatment device, a computer program and a computer-readable medium can be provided. List of reference symbols: 10 Treatment device 12 lasers 14 Cornea 16 Eye 18 Control device 20 laser beam 22 Beam deflection device 30 Fixing device 32 Suction device 34 Vacuum line 36 signal generators 38 Image recording device 50 target value 52 Limit 54 Time 56 Vacuum signal 58 Time 60 pupil 62 Center 63 points 64 Iris 65 Ellipse 66 Limit 68 Trajectory QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited non-patent literature

[0000] Chung B., Kang D.S.Y., Kim J.H., Arba-Mosquera S., Jean S.K., Jun I., Kim E.K., Seo K.Y., Kim K.Y., Kim T.I., „Clinical outcomes of immediate transepithelial photorefractive keratectomy after suction loss during small-incision lenticule extraction“. J. Cataract Refract Surg. 2020 May; 46(5):756-761

[0002]

Claims

[1] Method for controlling a treatment device (10) with an ophthalmological laser (12) for treating a human or animal eye (16), a control device (18) and a fixing device (30) for fixing the eye (16) for the treatment by means of negative pressure, - wherein during the treatment a course of a negative pressure signal is determined by the control device (18), - wherein the control device (18) checks whether a predetermined fixation instability criterion is met for the negative pressure signal, and - wherein, if the fixation instability criterion is present, the control device (18) sends a first control signal to the treatment device (10) in order to build up a negative pressure again, and if a renewed check of the negative pressure signal shows that the fixation instability criterion is no longer met, a second control signal is sent to the treatment device (10). [2] The method of claim 1, wherein the treatment of the eye (16) comprises a treatment of a refractive error of the eye (16). [3] A method according to claim 1 or 2, wherein the first control signal serves to interrupt the irradiation with the laser (12) and the second control signal serves to continue the irradiation with the laser (12). [4] Method according to one of the preceding claims, wherein the renewed build-up of the negative pressure is continued only after an optical check of an alignment of the eye (16), in particular after a realignment of the eye (16) with respect to the fixing device (30). [5] Method according to one of the preceding claims, wherein the fixation instability criterion is met if the negative pressure signal during the treatment exceeds or falls below a predetermined limit value (52) for at least a predetermined time period t1, if a change in the negative pressure signal exceeds or falls below a predetermined second limit value (52) for at least a predetermined time period t1, or if a change in the negative pressure signal has a predetermined sign for at least a predetermined time period t1. [6] Method according to one of the preceding claims, wherein the fixing device (30) comprises a plurality of intake channels with respective negative pressure signals, wherein the fixing instability criterion is met if at least one of the negative pressure signals exceeds a predetermined limit value (52) for at least a predetermined time period t1. [7] Method according to one of the preceding claims, wherein the vacuum signal comprises vacuum values of a vacuum in a vacuum line (34) through which the vacuum is supplied to the fixing device (30). [8] Method according to one of the preceding claims, wherein the treatment device (10) and / or the fixing device (30) comprises an image recording device (38), wherein the fixation instability criterion is checked by means of the image recording device (38). [9] Method according to claim 8, wherein the fixation instability criterion is met if it is determined by means of the image recording device (38) that a movement of the eye (16) during the treatment exceeds a predetermined limit value (66). [10] Method according to claim 8 or 9, wherein the fixing device (30) comprises a suction device (32), in particular a suction ring or suction-capable ring segments, by means of which the eye (16) is fixed by means of the negative pressure, and the fixing instability criterion is met if a detachment of the fixing device (30) from the eye (16) is detected. [11] Method according to one of claims 8 to 10, wherein the image recording device (38) additionally detects the transition from the suction device (32) to the eye (16), and the fixation instability criterion is met if it is determined by means of the image recording device (38) that blistering occurs at the transition during the treatment by means of the image recording device (38). [12] Method according to one of claims 8 to 11, wherein the image recording device (38) additionally detects the transition from the suction device (32) to the eye (16), and the fixation instability criterion is met if it is determined by means of the image recording device (38) that parts of the conjunctiva of the eye (16) become visible within the fixation device (30) during the treatment. [13] Method according to one of the preceding claims, wherein, if the fixation instability criterion is present, a warning message is issued to a user of the treatment device (10). [14] Control device (18) which is designed to carry out a method according to one of the preceding claims. [15] Treatment device (10) with at least one ophthalmic surgical laser (12) for separating a corneal volume with predefined boundary surfaces of a human or animal eye (16) by means of optical disruption, in particular by means of photodisruption and / or photoablation, a fixation device (30) and at least one control device (18) according to claim 14. [16] A computer program comprising instructions causing the treatment device (10) according to claim 15 to carry out a method according to any one of claims 1 to 13. [17] A computer-readable medium on which a computer program according to claim 15 is stored.

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