Control unit and console for an ophthalmic surgical system and ophthalmic surgical system

Abstract

Control device (102) for an ophthalmic surgical system (100), in which an ophthalmic surgical cassette (4) can be inserted into a cassette receptacle (101) of a console (1) of the ophthalmic surgical system (100), wherein the cassette (4) has at least one fluid pump (10, 20, 30, 40) for conveying a treatment fluid (3) through the cassette (4), for which purpose the at least one fluid pump (10, 20, 30, 40) has a pump chamber (11, 21, 31, 41) for the treatment fluid (3) and a drive chamber (13, 23, 33, 43) for a drive fluid, wherein the pump chamber (11, 21, 31, 41) and the drive chamber (13, 23, 33, 43) are separated by an elastic separating element (12, 22, 32, 42) are fluidically separated from each other, which is designed to be moved between two end positions of the separating element (12, 22, 32, 42) for a pumping stroke of the fluid pump (10, 20, 30, 40), wherein the drive chamber (13, 23, 33,43) with the insertion of the cassette (4) into the cassette receptacle can be fluidically coupled to a drive fluid source (17, 27, 37, 47) of the console (1), wherein the drive fluid source (17, 27, 37, 47) is designed to provide the drive fluid depending on a drive pressure control signal of the control device (102) with a predeterminable drive pressure, which can be detected by means of a drive pressure sensor (18, 28, 38, 48) of the console (1), wherein with the insertion of the cassette (4) into the cassette receptacle (101), a first surface of a detection membrane (50) of the cassette (4) can be mechanically contacted by a force sensor (51) of the console (1), wherein a second surface of the detection membrane (50) contacts the treatment fluid (3) contained in the cassette (4), wherein the control device (102) is designed to receive signals from at least the drive pressure sensor (18, 28, 38, 48), the force sensor (51) and a displacement sensor (19, 29, 39,49) of the console (1) for detecting a position of the separating element (12, 22, 32, 42) in the fluid pump (10, 20, 30, 40) and to provide the drive pressure control signal at least partially depending on the received signals, characterized in that the control device (102) is designed to provide a first drive pressure control signal for calibrating the force sensor (51) when the cassette (4) is inserted into the cassette holder (101) depending on the detection of one of the two end positions of the separating element (12, 22, 32, 42), so that the drive fluid source (17, 27, 37, 47) provides the drive fluid with a constant first drive pressure so that the separating element (12, 22, 32, 42) is moved from a first of the end positions to a second of the end positions, a temporal profile of a sensor signal, preferably at least one force signal of the force sensor (51) or one displacement signal of the displacement sensor (19, 29, 39, 49),to detect and evaluate during movement from the first of the end positions to the second of the end positions in order to determine a reference position of the separating element (12, 22, 32, 42) in the fluid pump (10, 20, 30, 40) in which the drive pressure corresponds to the fluid pressure of the treatment fluid, to determine a displacement signal of the displacement sensor (19, 29, 39, 49) corresponding to the reference position as a reference displacement signal, to detect a first force signal of the force sensor (51) in the reference position, and to calibrate the force sensor (51) depending on the first force signal and the first drive pressure.

Description

The invention relates to a control device according to the preamble of claim 1. Furthermore, the invention relates to a console for an ophthalmic surgical system for operating an ophthalmic surgical handpiece according to the preamble of claim 10.Ophthalmic surgical systems, consoles for this purpose and control devices, in particular for their operation for this purpose, are known in the prior art, so that in this regard a separate publication proof is fundamentally not required. For the treatment of eye lens opacification, in which medicine is also referred to as cataract or gray star, different surgical techniques are known. The most common is phacoemulsification, in which, for example, a thin hollow needle is introduced into a capsular bag in which an eye lens is arranged and excited to ultrasonic oscillations. The eye lens can be emulsified by means of the vibrating hollow needle, wherein lens particles released in this case can be suctioned off via an aspiration line by means of a pump. In this case, a flushing fluid or treatment fluid, also called irrigation fluid, is supplied. The lens particles are suctioned off together with the treatment fluid as aspiration fluid. Usually, the treatment fluid is a liquid such as a BSS solution or the like. Once the lens is completely emulsified and removed, a new artificial lens can be inserted into the then emptied capsular bag of the eye. This again allows a good vision to be achieved for the treated patient.A known ophthalmic surgical system for phacoemulsification is disclosed, for example, in DE 10 2016 201 297 B3. In this system, two fluid pumps connected in parallel in terms of flow are used for irrigation and also for aspiration. Each of the fluid pumps has a pump chamber and a drive chamber separated from the pump chamber by means of an elastic separating element. For the intended operation of the fluid pump, the drive chamber is charged with a drive fluid, the drive pressure of which is varied in order to carry out a respective pump stroke. As a result, a position of the elastic separating element changes depending thereon, which has a corresponding effect on the pump chamber. The pump chamber is charged with the respective treatment fluid, for example the irrigation fluid, the aspiration fluid or the like. By suitably controlling an inlet and an outlet valve of the respective fluid pump, the delivery effect can then be achieved.A position or a position of the respective elastic separating element in the fluid pump is detected by means of a displacement sensor assigned to the respective fluid pump. A control device of the ophthalmic surgical system controls, among other things, the function of the fluid pump at least as a function of a sensor signal of the displacement sensor and a drive pressure sensor signal provided by means of a drive pressure sensor. Preferably, the control means may control the intake and exhaust valves accordingly. The console can have the control device at least partially or completely, for example.By alternating actuation of the two parallel-connected fluid pumps, a volume flow with very small fluctuations can be achieved during an operation. As a result, a virtually constant intraocular pressure can be established in the capsular bag. As long as sufficient irrigation fluid can be supplied, the system can be operated almost without interrupting the irrigation fluid flow even during a very long-lasting operation.The elastic separating element of a respective one of the fluid pumps is thus not actuated by a piston or a rod, but rather by the drive fluid. The drive fluid can be, for example, a liquid such as water, oil or the like or else a gas, for example air, nitrogen, a gas mixture or the like. As a result, an almost jerk-free and at the same time very rapid actuation can be achieved. In addition, the fluid pump realized in this way has a very low maintenance and is reliable. The ophthalmic surgical system disclosed in DE 10 2016 201 297 B3 is therefore also particularly suitable for a method procedure which requires a reaction in the event of a needle tip of the hollow needle or an extraction opening being blocked. Such a state is also referred to as occlusion. With the ophthalmic surgical system presented in DE 10 2016 201 297 B3, this situation can also be handled very well, so that an intraocular pressure can be kept almost constant even in the case of such disturbances during operation.For the intended operation of the ophthalmic surgical system, it is desirable to keep the intraocular pressure, in particular in the capsular bag, as constant as possible by regulating the fluid pressure of the irrigation fluid and the vacuum of the aspiration fluid. For this purpose, it is desirable to know the fluid pressure of the treatment fluid as accurately as possible so that a correspondingly accurate control of this fluid pressure can be achieved. In the above-described fluid pump, the fluid pressure of the treatment fluid depends on the driving pressure of the driving fluid. In addition, there is also a dependence on properties of the separating element. Due to component variations and tolerances as well as aging effects due to mounting or the like, deviations of the properties occur between different separating elements. These deviations can relate, for example, to a dependence of a pressure difference caused by the separating element on a respective position or position of the separating element. Such a deviation may be over a desired range of accuracy which is useful for controlling intraocular pressure.In this connection, it should be noted that the ophthalmic surgical system is often designed in such a way that the console has a cassette receiving region in which a cassette can be arranged, preferably in a detachable manner. The cassette can therefore be designed as an exchangeable component. This makes it possible to realize the cartridge as a disposable cartridge which is intended for a single application or a limited number of successive applications. Following application, the cassette may be removed and replaced with another cassette for further use of the ophthalmic surgical system. The used cassette can then be disposed of or recycled.This makes it possible to arrange all regions which are exposed to the treatment fluid during the intended use on the cassette side. Other units and devices required for the intended use, such as the sensors, the drive fluid source and / or the like, can, on the other hand, be arranged on the console side. As a result, expensive sensors and drives can be arranged in the console and do not need to be arranged in the cassette. This cost-effective construction of the cassette can, however, generally lead at least to relevant deviations of the properties of the at least one separating element from different cassettes. This requires that the ophthalmic surgical system, when the cassette is located in the cassette holder of the console, be calibrated at the beginning of the intended use. This relates in particular to the force sensor and the at least one separating element and optionally also the at least one travel sensor.It is the object of the invention to improve an operation of an ophthalmic surgical system to the effect that, in particular, a regulation with respect to the conveying of the treatment fluid can be realized more accurately in the case of different cassettes.As a solution, the invention proposes a control device for an ophthalmic surgical system, a console for an ophthalmic surgical system and an ophthalmic surgical system according to the independent claims.Advantageous further developments are obtained by features of the dependent claims.With respect to a generic control device for an ophthalmic surgical system, in which an ophthalmic surgical cassette can be inserted into a cassette receptacle of a console of the ophthalmic surgical system, wherein the cassette has at least one fluid pump for conveying a treatment fluid through the cassette, for which purpose the at least one fluid pump has a pump chamber for the treatment fluid and a drive chamber for a drive fluid, wherein the pump chamber and the drive chamber are fluidically separated from one another by a, preferably elastic, separating element, wherein the separating element is in particular designed to be moved between two end positions of the separating element for a pump stroke of the fluid pump, wherein the drive chamber can preferably be fluidically coupled to a drive fluid source of the console when the cassette is inserted into the cassette receptacle, wherein the drive fluid source is preferably designed to be fluid-coupled to a drive fluid source of the console, providing the drive fluid with a prescribable drive pressure depending on a drive pressure control signal of the control device, which drive pressure is preferably detectable by means of a drive pressure sensor of the console, wherein, when the cassette is inserted into the cassette holder, a first surface of a detection membrane of the cassette is mechanically contactable by a force sensor, preferably a force sensor of the console, wherein a second surface of the detection membrane contacts the treatment fluid contained in the cassette, wherein the control device is preferably designed to receive and evaluate signals from at least the drive pressure sensor, the force sensor and a travel sensor of the console for detecting a position of the separating element in the fluid pump and to provide the drive pressure control signal at least partially depending on the received signals, it is proposed in particular that the control device is designed, in the case of the cassette inserted into the cassette holder for calibrating the force sensor, a first drive pressure control signal is provided as a function of the detection of one of the two end positions of the separating element, such that the drive fluid source provides the drive fluid at a substantially constant first drive pressure, in order that the separating element is preferably moved from a first of the end positions into a second of the end positions, to detect and evaluate a temporal profile of a sensor signal, preferably at least one force signal of the force sensor or a displacement signal of the displacement sensor, during the movement from the first of the end positions into the second of the end positions, in order in particular to determine a reference position of the separating element in the fluid pump, in which the drive pressure corresponds to the fluid pressure of the treatment fluid, to determine a displacement signal of the displacement sensor corresponding to the reference position as a reference displacement signal, in the reference position, a first force signal of the force sensor is detected, and the force sensor is calibrated as a function of the first force signal and the first drive pressure.With respect to a console of the generic type for an ophthalmic surgical system for operating an ophthalmic surgical handpiece, which can be connected to the console, it is proposed in particular that the console has at least one cassette receptacle for arranging an ophthalmic surgical cassette, wherein the cassette has at least one fluid pump for conveying a treatment fluid through the cassette, for which purpose the at least one fluid pump has a pump chamber for the treatment fluid and a drive chamber for a drive fluid, wherein the pump chamber and the drive chamber are separated from one another in terms of fluid technology by an, in particular elastic, separating element, wherein the console preferably has at least one drive fluid source, preferably at least one drive pressure sensor, which can be coupled in terms of fluid technology to the drive chamber of the cassette, for detecting a drive pressure of the drive fluid source, Preferably at least one displacement sensor for detecting a position of the separating element in the fluid pump, preferably at least one force sensor for mechanically contacting a detection membrane of the cassette, wherein the detection membrane contacts the treatment fluid contained in the cassette, and preferably has a control device at least for controlling the drive fluid source, wherein the control device is designed to receive and evaluate at least signals of the at least one drive pressure sensor, the at least one displacement sensor and the at least one force sensor and, depending on the evaluation, to provide a drive pressure control signal for controlling the drive pressure to be provided by the drive fluid source, wherein the control device is designed according to the invention.With respect to a generic ophthalmic surgical system, the invention proposes in particular that it comprises: an ophthalmic surgical handpiece, an ophthalmic surgical cassette, wherein the cassette comprises at least one fluid pump for conveying a treatment fluid through the cassette, for which purpose the at least one fluid pump comprises a pump chamber for the treatment fluid and a drive chamber for a drive fluid, which can be fluidically coupled to a drive fluid source, preferably to a drive fluid source of a console, wherein the pump chamber and the drive chamber are fluidically separated from one another by a, preferably elastic, separating element, and wherein the cassette comprises a detection membrane, which contacts the treatment fluid contained in the cassette and can preferably be mechanically contacted by a force sensor, preferably a force sensor of the console, a console having a cassette holder for mounting the ophthalmic surgical cassette, the console being constructed in accordance with the invention.The invention is based, inter alia, on the idea that, before an intended use of the ophthalmic surgical system is recorded, at least the force sensor and the at least one separating element and, if appropriate, also the at least one travel sensor are calibrated, so that the control device can provide the desired intended operation-as explained above. In this context, it is advantageous to provide a calibration of the force sensor first. As soon as the force sensor is calibrated, it can be used to calibrate the at least one displacement sensor as well, if necessary, and to generate a characteristic curve for the at least one separating element, which characteristic curve indicates, for example, a dependence of a force effect of the at least one separating element on a position in the pump, as far as this proves to be necessary. With regard to calibrating the force sensor, it should be noted that it may have a sensor surface which mechanically contacts the first surface of the sensing membrane. The first surface is in particular an outer surface of the detection membrane, which is at the same time also a part of an outer surface of the cassette. The second surface of the detection membrane is in particular an inner surface of the cassette which is in fluidic connection, preferably directly, with a flow path for the treatment fluid. The cassette is preferably configured such that the second surface can contact the treatment fluid. The fluid pressure of the treatment fluid can therefore act on the sensing membrane. The treatment fluid contacting the second surface is intended to be in fluidic communication with the pump chamber of the at least one pump. That is, for detecting the force by means of the force sensor, it is preferable to have a state in which the fluid pressure of the treatment fluid in the pump chamber substantially corresponds to the fluid pressure of the treatment fluid in the region of the detection diaphragm. This can be achieved, for example, by actuating suitable valves of the cassette, which can be actuated, for example, by means of valve drives of the console. The valve drives can be controlled with valve control signals of the control device. It is therefore of course also possible for the force sensor to be designed, for example, to detect a force in a contactless manner, for example optically, capacitively or the like. However, the calibration process is just as necessary here as for the contact-requiring force sensor explained above. The invention can also be applied equally in the case of a force sensor which detects the force in a contactless manner.The first and the second end position can preferably be positions of the separating element at which the separating element in the fluid pump can be maximally deflected in the respective direction starting from a relaxed position of the separating element. However, the first and the second end position can also be predetermined or predeterminable positions which have proven to be suitable end positions for the invention from experience, because it has been shown, for example, that the relaxed position of the separating element is generally always between these two end positions.The sensor signal may be the sensor signal of a suitable sensor that detects a characteristic of a behavior of the separator element. The sensor signal need not be calibrated. Both when the sensor signal is the force signal, for example, and when the sensor signal is the travel signal, for example, it is preferably sufficient to determine a relative signal profile of the sensor signal at least partially. The signal profile can be determined continuously or discretely. By the evaluation, for example, a characteristic with respect to the relaxed position of the separating element in the signal profile is determined. As a rule, a specific behavior of the sensor signal can be determined at least in the region of the relaxed position of the separating element. This may allow the relaxed position of the separator to be determined.Moreover, it should be borne in mind that the elastic separating element of a respective pump chamber initially has unknown properties and the fluid pressure of the treatment fluid in the pump chamber can deviate in some cases considerably from the drive pressure of the drive fluid in the drive chamber depending on a respective position of the separating element in the pump chamber. The drive pressure of the drive fluid can be detected by means of a drive fluid pressure sensor arranged in the console. The drive fluid pressure sensor can provide a corresponding sensor signal to the control device. The possible positions of the separating element in the pump are mechanically limited by the two end positions which are different from one another and which the separating element can assume during normal operation at a respective maximum deflection. The pump stroke can therefore preferably be determined by a movement or displacement of the separating element from one of the end positions into the second of the end positions, as a result of which a maximum possible displacement stroke can be determined. The first end position can be, for example, a state of the fluid pump in which the pump chamber of the fluid pump is maximally filled with the treatment fluid. Accordingly, the drive chamber is minimally filled with the drive fluid. In the second end position, there may be an opposite state in which the drive chamber is filled to a maximum extent with the drive fluid, whereas the pump chamber is filled to a minimum extent with the treatment fluid.At the beginning of the calibration process, however, the respective properties are not yet known. However, it has been found that when the separating element is moved from one of the end positions into the second of the end positions at a substantially constant drive pressure of the working fluid, in an intermediate position between the two end positions the separating element assumes the relaxed position in which, owing to its elasticity and arrangement in the pump, the separating element exerts substantially no force on the drive fluid in the drive chamber and the treatment fluid in the pump chamber. This position is also referred to below as a reference position. In the reference position, the drive pressure may substantially correspond to the fluid pressure of the treatment fluid. For carrying out the calibration process, it can be provided, for example, that a fluid outlet of the cassette is open for the treatment fluid. However, it can also be provided, for example, that the fluid outlet for the treatment fluid is connected to an inlet of the cassette for an aspiration fluid. The control device can enable a flow of the treatment fluid by suitable actuation of valves of the cassette. This makes it possible to calibrate the force sensor.The concrete values of parameters and details regarding ratios of parameters or parameter values for defining exemplary embodiments of the device specified in the documents are also to be considered included within the scope of the invention within the scope of deviations, for example due to measurement errors, system errors, DIN tolerances and / or the like, as a result of which explanations relating to substantially corresponding values and details are also to be understood as included. The same applies to features such as "constant" or "equal".The control device is preferably designed to subsequently provide a second drive pressure control signal, so that the drive fluid source provides the drive fluid at a constant second drive pressure, to detect a second force signal of the force sensor at the reference position of the separating element and to calibrate the force sensor as a function of the first and the second force signal and the first and the second drive pressure. In addition, when the separating element is moved between the two end positions, it is found that a relative temporal profile of a respective value of at least the sensor signal of the displacement sensor or the sensor signal of the force sensor has a characteristic temporal profile. From the respective characteristic time profile, the control device can determine the reference position as part of the evaluation of the respective sensor signal. If the reference position is determined, at least one second fluid pressure can be provided in the treatment fluid as a function thereof by changing the drive pressure to the second drive pressure and moving the separating element into the reference position. For this purpose, a second force signal can be provided by means of the force sensor. In this way, at least two value pairs can be determined, on the basis of which the control device can calibrate the force sensor in cooperation with the detection membrane. There is therefore the possibility of creating at least partially a characteristic curve for the force sensor in conjunction with the sensing membrane. It can be provided that only the displacement signal or the force signal is evaluated for determining the reference position. However, it can also be provided that the characteristic time curves of the two sensor signals are evaluated. If the force sensor is calibrated, further calibrations can be carried out or further properties of the cassette can be determined, for example a characteristic curve for the separating element.The invention is accordingly applied to an ophthalmic surgical system in which an ophthalmic surgical cassette can be inserted into a cassette receptacle of a console of the ophthalmic surgical system. At least one fluid pump is provided on the cassette side for conveying the treatment fluid through the cassette. For this purpose, the at least one fluid pump has a pump chamber for the treatment fluid and a drive chamber for the drive fluid. The pump chamber and the drive chamber are fluidically separated from one another by the elastic separating element. As the cartridge is inserted into the cartridge receptacle, the console drive fluid source is fluidly coupled to the cartridge drive chamber. Thus, by appropriately providing the drive fluid, the actuation of the fluid pump for pumping the treatment fluid can be achieved. The intended use after carrying out the calibration is known from the aforementioned prior art, for which reason reference is made in this respect to the corresponding disclosures.By using the force sensor, it can be achieved that a pressure sensor for detecting the fluid pressure of the treatment fluid can be avoided. This makes it possible to provide the cassette as a sterile disposable component which is generally provided for use or a limited number of intended uses of the ophthalmic surgical system. A statement about the fluid pressure of the treatment fluid can therefore be achieved in the intended operation only by means of the force sensor, for which purpose the cassette-specific calibration of the force sensor is provided. The travel sensor or position sensor can be, for example, a capacitive, inductive, resistive or similar travel sensor. The position of the separating element can be detected, for example, as explained in DE 10 2021 124 415 A1.The control device is preferably designed as an electronic control device, which can have, for example, an electronic hardware circuit and / or a program-controlled computer unit, in order to be able to realize the desired intended function. The console can have the control device at least partially. However, it can also be provided that the console has the control device completely, for example is a device of the console. In addition, it is possible for the control device to be a separate module which is formed separately from the console and is in communication connection with the console, in particular the corresponding sensors and drives. The control device can also be formed at least partially with respect to the ophthalmic surgical system by an external unit which is in communication with the ophthalmic surgical system, in particular the console. The control device provides a method control with which at least the force sensor can be calibrated.Preferably, the sensor signals and / or the control signals are analog or digital signals. A combination thereof can also be provided, wherein only a part of the signals is formed by digital signals and a part of the signals is formed by analog signals. The control device is designed to process or provide the signals accordingly.It is further proposed that the control device is designed to determine a relative maximum value of the force signal when evaluating the time profile of the force signal and to define the value of the travel signal present at the time of the relative maximum value of the force signal as the reference travel signal corresponding to the reference position of the separating element. This reference position can be detected by means of the displacement sensor. However, at least one further, second, deviating measurement is required for calibrating the force sensor. This is achieved by changing the drive pressure of the drive fluid to the second drive pressure, for example by increasing it. For this purpose, the control device can provide a corresponding second drive pressure control signal for the drive fluid source. For this reason, a further force could now already be detected with the force sensor at this position or in this position. However, it should be borne in mind that the separating element is no longer in the reference position, that is to say that the properties of the reference element have an effect on the force detection by means of the force sensor. Therefore, the invention further provides that the drive pressure source is controlled by means of the control device, taking into account the sensor signal of the displacement sensor, in such a way that the reference position is reached again. In the reference position, it is already known that the effect of the separating element can be neglected. Therefore, in this position, the corresponding force can now be determined again by means of the force sensor. Since the corresponding drive pressures are known, it is thus possible for the control device to determine the calibration of the force sensor from the determined or determined values. The calibration of the force sensor determined in this way can then be used as a basis for the intended use of the ophthalmic surgical system.In addition, it is proposed that the control device is designed to determine an inflection point when evaluating the temporal profile of the path signal and to define the value of the path signal present at the time of the inflection point as the reference path signal corresponding to the reference position of the separating element. It has been shown that the time profile of the path signal has an inflection point in the region of the reference position. By signal-technical processing of the time profile of the path signal, the control device can determine this inflection point, for example using mathematical derivatives, in particular a second derivative. The time profile of the path signal can be digitized for this purpose, for example. A corresponding signal processing can be carried out, for example, by means of a program-controlled computer unit of the control device. The reference path signal can be determined numerically, for example.In addition, it is proposed that the control device is designed to determine correction data, at least with respect to a dependence of the respective fluid pressure on the respective drive pressure, by means of a regression method, taking into account the properties of the separating element. By using the regression method, it can be achieved that the correction data becomes more accurate, so that more precise control of the ophthalmic surgical system can be achieved during the intended use. In addition, it is of course also possible to be able to achieve a high accuracy for the correction data with already a few measurement points, so that the effort for determining the correction data can be reduced overall.According to a further development, it is proposed that the control device is designed to detect the insertion of the cassette into the console and to calibrate at least the force sensor depending on the detection of the insertion. In this way, it is possible to start and carry out the calibration process automatically at least in part, so that separate actions or settings need not be carried out in this regard. For this purpose, it can be provided that a corresponding sensor is arranged in the console, in particular in the region of the cassette holder, which sensor is capable of detecting the arrangement of the cassette in the cassette holder. This sensor is preferably in communication with the control device by signal technology, so that the control device is informed of the insertion of the cassette into the cassette holder. The control device can then, for example, start the calibration process at least for the force sensor depending on the corresponding sensor signal.It is furthermore proposed that the control device is designed to repeat at least the calibration of the force sensor or the calibration of the displacement sensor at at least one predefined time or in the case of at least one predefined event. This further development makes it possible to take account of changes in the cassette occurring during the intended use by recalibration. For this purpose, it can be provided that the control device emits a corresponding calibration signal, so that a user of the ophthalmic surgical system can interrupt the use, whereupon the control device then repeats the calibration process accordingly. The calibration signal can be, for example, an optical and / or acoustic signal that can be perceived by the user of the ophthalmic surgical system. For example, this can take place after a predefined time period from the beginning of the intended use, for example after half an hour, after an hour or the like. However, it can also be provided that a force acting from the outside on the cassette in an undesired manner changes the position of the cassette in the cassette holder, whereupon under certain circumstances properties of the force sensor and of the displacement sensor can also be affected. If such a force effect is detected with a corresponding sensor, a corresponding repetition of the calibration can also be provided in this case.It is furthermore proposed that the control device is designed to carry out at least the calibration of the force sensor or the calibration of the at least one separating element during an initialization of the ophthalmic surgical system. The initialization of the ophthalmic surgical system can in particular comprise a so-called priming (priming) of the system, in particular of the cassette. Preferably, priming is performed before performing the calibration of the ophthalmic surgical system or cassette. In this way, it is possible to integrate the calibration into the intended use or into the start of use without great additional effort.It is furthermore proposed that the control device is designed to provide a fluid control signal for a valve of the treatment fluid source or a second fluid pump. The second fluid pump may be, for example, a second fluid pump of the cartridge. The second fluid pump can be, for example, a fluid pump which serves for conveying an aspiration fluid. The valve, which can be controlled by means of the fluid control signal, can be designed, for example, in the manner of a directional valve, a proportional valve and / or the like. The treatment fluid source or cassette may include the valve. The control device can provide a control signal for the treatment fluid source. Depending on this control signal, the treatment fluid source can adjust the fluid pressure of the treatment fluid. Depending on this, it is thus possible to vary the fluid pressure of the treatment fluid, in particular for the method management for realizing the calibration of the force sensor, and optionally also of the at least one separating element.The advantages and effects indicated for the control device according to the invention naturally also apply correspondingly equally to the console at least partially equipped with the control device according to the invention and to the ophthalmic surgical system comprising the console according to the invention and vice versa.Further features of the invention are evident from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description, and the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, 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 of the invention are also to be considered as included and disclosed which are not explicitly shown and explained in the figures, but which emerge from the explained embodiments and can be generated by separate combinations of features. Embodiments and combinations of features are also to be considered as disclosed, which therefore do not have all features of an originally formulated independent claim. Furthermore, embodiments and combinations of features, in particular by the embodiments set forth above, are to be considered as disclosed which go beyond or deviate from the combinations of features set forth in the references of the claims.The figures show: FIG. 1 shows a schematic illustration of a first embodiment of an ophthalmic surgical system, FIG. 2 shows a schematic perspective illustration of a console of the system according to FIG. 1, FIG. 3 is a schematic top view of a connection side of a cassette for the system according to FIG. 1 , FIG. 4 shows a schematic representation of a flow chart for a method procedure carried out by a control device of the system according to FIG. 1 for calibrating a force sensor and displacement sensors of the ophthalmic surgical system according to FIG. 1, FIG. 5 shows a schematic sectional illustration of one of the fluid pumps according to FIG. 1, in which a separating element of the fluid pump is illustrated in a first position, FIG. 6 shows a schematic sectional illustration like FIG. 5, in which the separating element of the fluid pump is illustrated in a second position, FIG. 7 shows a schematic sectional illustration like FIG. 5, in which the separating element of the fluid pump is illustrated in a third position, and FIG. 8 shows a schematic diagram illustration, in which a first graph represents a temporal profile of a position of the separating element of one of the fluid pumps according to FIG. 1 from a first end position into a second end position, and a second graph represents a corresponding relative force signal of a force sensor according to FIG. 1.FIG. 1 shows a schematic illustration of a first embodiment of an ophthalmic surgical system 100. The system 100 has a console 1, to which an irrigation fluid container 2 with an irrigation fluid 3 contained therein as treatment fluid is coupled. Furthermore, the system 100 has a cassette 4, which can be inserted in a cassette receptacle 101 of the console 1 (FIG. 2 ). In addition to conveying the irrigation fluid 3 to a surgical instrument, not shown, which serves as a treatment for the phacoemulsification of a lens of an eye, the cassette 4 also serves for removing an aspiration fluid arising in this case from a treatment region of the eye. The surgical instrument is designed, for example, as a handpiece and serves for the phacoemulsification of the lens of the eye. FIG. 2 shows a schematic perspective illustration of the console 1 without the cassette 4.FIG. 3 shows a schematic top view of a connection side of the cassette 4 for connection to the console 1.The system 100 further includes an irrigation fluid flow path 8 extending from the irrigation fluid container 2 to the surgical instrument via the cassette 4. In addition, the system 100 has a first fluid pump 10 with a first pump chamber 11 and a first drive chamber 13, which is separated therefrom by a first elastic separating element 12 and is arranged in the cassette 4. The first elastic separating element 12 has an edge 14, by means of which it is arranged fixedly in the fluid pump 10. As can be seen from FIG. 1, the drive chamber 13 and the pump chamber 11 with the separating element 12 are arranged in the cassette 4.The irrigation fluid 3 can be supplied to the first pump chamber 11 via the irrigation fluid flow path 8 and a first inlet valve 15 depending on a valve state of the inlet valve 15 of the first pump chamber 11. Furthermore, it can be discharged again from the pump chamber 11 via an outlet valve 16, depending on its valve state. The first drive chamber 13 can be supplied with a first drive fluid, which can be supplied from a drive fluid source 17 by means of a proportional valve 18 arranged in the console 1. Furthermore, the console 1 has a first drive pressure sensor, not shown in the figures, which is designed to sense the drive pressure of the first drive fluid in the drive chamber 13. During the application of the first drive fluid to the first drive chamber 13, an elastic deformation or deflection of the first elastic separating element 12 occurs, wherein the irrigation fluid 3 is conveyed out of the first pump chamber 11 as treatment fluid. For this purpose, the inlet valve 15 is closed and the outlet valve 16 is open, so that the irrigation fluid 3 can flow out of the first pump chamber 11 into a sub-path 83 connected to the outlet valve.The position or the position of the first elastic separating element 12 can be detected by means of a first displacement sensor 19 which is arranged outside the first fluid pump 10, for example in the console 1. The first travel sensor 19 can be designed, for example, as an inductive or capacitive travel sensor.It can also be seen from FIG. 1 that a second fluid pump 20 is fluidically connected in parallel with the fluid pump 10. The fluid pump 20 is designed in the present case like the fluid pump 10. Therefore, the irrigation fluid flow path 8 in the cassette 4 is divided into a first sub-path 81 and a second sub-path 82. The first partial path 81 is connected to the first inlet valve 15 and the second partial path 82 is connected to a second inlet valve 25 of the second fluid pump 20.The second fluid pump 20 has a second pump chamber 21 and a second drive chamber 23 separated therefrom by means of a second elastic separating element 22. The separator 22 has a second rim 24 fixedly mounted in the second fluid pump 20. The second drive chamber 23 can be supplied with a second drive fluid from a drive fluid source 27 via a second proportional valve 28 arranged in the console 1. The console 1 further includes a second drive pressure sensor, not shown in the figures, for detecting the drive pressure of the second drive fluid in the second drive chamber 23. A position of the separating element 22 can be detected by means of a displacement sensor 29. Via a second outlet valve 26, the irrigation fluid 3 can leave the second pump chamber 21 again into the partial path 84. Via the partial paths 83, 84, which are connected to the respective first and second outlet valves 16, 26, the irrigation fluid 3 leaving the respective fluid pump 10, 20 can be fed back to the irrigation fluid flow path 8 in order to be supplied to the instrument.In a region of the fluidic connection of the sub-path 83 to the sub-path 84, i.e. for example in the subsequent irrigation fluid flow path 8, an elastic detection membrane 50 is formed. The sensing membrane 50 has a first surface and a second surface opposite the first surface. The second surface is fluidically connected to the irrigation fluid flow path 8 so that it can contact the irrigation fluid 3. The detection membrane 50 is disposed on the cartridge 4. When the cassette 4 is inserted into the cassette holder 101, the first surface of the detection membrane 50 is mechanically contacted by a force sensor 51 which is in turn arranged in the console 1. The detection membrane 50 forms a detection sensor 52 in conjunction with the force sensor 51. The force sensor 51 may also include, for example, a strain gauge for detecting the force.During the comminution of the eye lens, small lens particles are released, which can be sucked off together with the introduced irrigation fluid 3. The irrigation fluid 3 contaminated with lens particles is then referred to as aspiration fluid and conveyed via an aspiration fluid flow path 9 to an aspiration fluid collection container 53. For this purpose, the cassette has two further parallel-connected fluid pumps 30, 40, which are basically designed to be comparable to the fluid pumps 10, 20 for the irrigation fluid. For this purpose, it is provided within the cassette 4 that the aspiration flow path 9 likewise divides into two partial paths 91, 92, which are connected via respective inlet valves 35, 45 to the respective fluid pumps 30, 40, namely respective pump chambers 31, 41 here as well. Here as well, the pump chambers 31, 41 are separated from respective drive chambers 33, 43 via respective elastic separating elements 32, 42. The separators 32, 42 have respective edges 34, 44 fixedly mounted in the respective fluid pump 30, 40. The aspiration fluid can then be discharged via the aspiration fluid flow path 9 via respective outlet valves 36, 46 and partial paths 93, 94 connected thereto.A third drive fluid of a drive fluid source 37 can be conducted to the third drive chamber 33 by means of a third proportional valve 38. The console 1 has a third drive pressure sensor, not shown in the figures, for detecting the drive pressure of the third drive fluid in the third drive chamber 33. Accordingly, a fourth drive fluid of a drive fluid source 47 can be conducted by means of a fourth proportional valve 48 to a fourth drive chamber 43. The console 1 has a fourth driving pressure sensor, not shown in the figures, for detecting the driving pressure of the fourth driving fluid in the fourth driving chamber 43. The proportional valves 38, 48 are arranged in the console 1. The positions of the separating elements 32, 42 can be detected by means of respective displacement sensors 39, 49 of the console 1. The two fluid pumps 30, 40 are in the present case likewise operated alternately like the fluid pumps 10, 20.The console has a control device 102 which is connected, inter alia, to the sensors by signal technology. In particular, the control device 102 is connected by signal technology to the travel sensors 19, 29, 39, 49 and the force sensor 51. Furthermore, the control device 102 is connected to the proportional valves 18, 28, 38, 48 and valve drives of the console 1 for the valves 15, 16, 25, 26, 35, 36, 45, 46 so that it can control these by means of corresponding control signals. At the same time, drive pressure signals of the proportional valves 18, 28, 38, 48 can be received.Each of the fluid pumps 10 to 40 serves to convey the respective treatment fluid, which in the present case is the irrigation fluid 3 or the aspiration fluid. It has been found that the properties of the fluid pump 10 to 40 are dependent, inter alia, on the respective separating elements 12 to 42, the mechanical behavior of which can vary greatly from fluid pump to fluid pump. However, knowing the properties of the fluid pumps 10 to 40, in particular of the separating elements 12, 22, 32, 42, is necessary for as precise as possible a regulation of the supply of the irrigation fluid 3 to the instrument or the as precise as possible discharge of the aspiration fluid. An exact regulation is intended to serve, among other things, for the purpose that an intraocular pressure, in particular in a capsular bag, is as constant as possible during the treatment, so that the capsular bag which accommodates the eye lens to be removed is as little stress as possible. This can be achieved by calibration.A calibration process for calibrating the force sensor 51 will be explained below.FIGS. 5 to 7 each show, by way of example, a schematic sectional view of the fluid pump 10 of the cassette 4 according to FIG. 1, FIG. 5 shows that the pump chamber 11 is filled to the maximum with the treatment fluid 3, and the separating element 12 is thus positioned in the direction of the drive chamber 13. FIG. 5 shows a first of the two end positions of the separating element 12; FIG. 6 shows, in a schematic sectional view like FIG. 5, an intermediate state in which a part of the treatment fluid 3 has been discharged from the pump chamber 11 by drive fluid having been supplied to the drive chamber 13. FIG. 7 shows the further supply of drive fluid into the drive chamber 13, so that the separating element 12 has conveyed the treatment fluid 3 out of the pump chamber 11 almost completely. FIG. 7 shows a second of the two end positions of the separating element 12, and FIGS. 5 to 7 thus show an almost complete displacement stroke of the separating element 12 in the fluid pump 10, which in the present case corresponds to a pump stroke. The process shown here is, of course, reversible. It is not shown, moreover, that the position of the separating element 12 can be detected by means of the displacement sensor 19. The calibration of the displacement sensor 19 can be realized, for example, inter alia by detecting a value of the sensor signal of the displacement sensor 19 in the two end positions of the separating element 12 according to FIGS. 5 and 7. This also applies in the present case to the further fluid pumps 20, 30, 40.For the purpose of carrying out the method, it is provided in the present case that during the calibration, the irrigation fluid flow path 8 is fluidically short-circuited to the aspiration fluid flow path 9. Accordingly, for calibrating the force sensor 51, it is provided that corresponding valves are in the open state in the aspiration path. Basically, however, it is also possible to leave the irrigation fluid flow path 8 open, so that the irrigation fluid 3 can flow out as required during the calibration process. The return via the aspiration fluid flow path 9, on the other hand, has the advantage that the fluid can be guided to the aspiration fluid collecting container 53 and collected. The fluidic short circuit is produced by a fluidic connecting element 72 and can be opened after the calibration process in order to connect a handpiece serving as an instrument for recording the intended use of the ophthalmic surgical system.For calibration purposes, a method procedure as is provided with reference to the schematic flow diagram 60 according to FIG. 4 is provided in the present case. The method is based on the realization that the force sensor 51 provides a not yet calibrated relative time profile of a force signal for the control device 102 when the separating element 12 is moved from the first end position into the second end position in the fluid pump 10 that differs from the first end position. The time profile of the force signal shows a relative maximum value at a specific time t 1. This situation is explained with reference to FIG. 8 in a schematic diagram representation.In FIG. 8, an abscissa is assigned to time. A left ordinate is associated with a signal value of the force sensor 51 and indicates a force in N. A right ordinate is assigned to a signal value of the displacement sensor 19, which emits a voltage signal in V depending on a detected position of the separating element 12 in the fluid pump 10. A graph 70 shows a time profile of the sensor signal of the displacement sensor 19 during a movement of the separating element 12 over time, as explained with reference to FIGS. 5 to 7. A graph 71 shows a temporal profile of the sensor signal provided by the force sensor 51 for the same period of time. It can be seen that at a time t 1 the value of the sensor signal provided by the force sensor 51 has an, in particular local, maximum. It has been shown that this maximum is an indicator that the separating element 12 is in a position in which there is substantially approximately equal pressure between the drive chamber 13 and the pump chamber 11. In this position, the effect of the separating element 12 on the pressure conditions in the fluid pump 10 can thus be neglected. This position of the separating element 12 is also referred to below as a reference position. When the separating element 12 is moved out of the reference position, a restoring force acts due to the elasticity of the separating element 12, which restoring force brings about a pressure difference between the drive chamber 13 and the pump chamber 14First, after the cassette 4 has been inserted into the cassette holder 101, the force sensor 51 is calibrated. For this purpose, the irrigation fluid flow path 8 is fluidically connected to the aspiration fluid flow path 9 via the fluidic connection element 72. Alternatively, the irrigation fluid flow path 8 could also remain simply open without termination, so that the irrigation fluid 3 can flow out during calibration.Then, in a step 61, the controller 102 provides a driving pressure control signal to the first driving fluid source 17 so that the partition member 12 reaches the position shown in FIG. 5. During step 61, valve 15 is open, whereas valve 16 is closed.The control device 102 then provides a first drive pressure control signal to the drive fluid source 17 in a step 62 in order for the drive fluid source 17 to provide a first drive pressure. During step 62, valve 15 is closed, whereas valve 16 is open. The separating element 12 is moved from the first end position into the second end position in the fluid pump 10. During the movement of the partition member 12, the force sensor 51 detects a force and provides the force signal as a sensor signal depending on the detected force. The control device 102 receives the force signal and determines the time profile of the force signal. This results in a time profile of the force signal, as is illustrated by means of the graph 71 in FIG. 8.In a step 63, the control device 102 evaluates the time profile of the force signal and determines the relative maximum value of the force signal. It can be seen from FIG. 8 that this relative maximum value of the force signal occurs at a time t 1. This value of the force signal is stored as a first force signal. At the same time, the control device 102 receives a sensor signal of the displacement sensor 19 as the displacement signal.Then, in a step 64, the drive fluid source 17 is controlled by the control device 102 with a second drive pressure control signal in such a way that the drive fluid source 17 provides a constant second drive fluid pressure. The partition member 12 moves again. By controlling the valves 15, 16, irrigation fluid is fed into the pump chamber 14 to move the separating element 12 back into the reference position. The reaching of the reference position can be determined by means of the displacement sensor 19.As soon as the separating element 12 again assumes the reference position, a second force signal of the force sensor 51 is received by the control device 102 in a step 65. This force signal is stored as a second force signal.In a step 66, the control device 102 evaluates the first and the second force signal and the first and the second drive pressure and calibrates the force sensor 51 depending on the evaluation.Alternatively or additionally, the control device 102 can be designed to determine an inflection point in the time profile of the path signal with the evaluation with respect to the time profile of the path signal. The inflection point is present at time t 1. The value of the path signal at the inflection point may be set as the reference path signal corresponding to the reference position of the separator 12, 22, 32, 42. For this purpose, the control device 102 can digitize the ascertained temporal profile of the path signal and process it numerically within the scope of the evaluation in order to determine the inflection point. This can be seen on the basis of the graph 70 in FIG. 8. This embodiment uses the realization that the time profile of the path signal has an inflection point at the reference position. When the partition member 12, 22, 32, 42 is moved through the reference position, the restoring force caused by the partition member 12, 22, 32, 42 changes direction.The reference position of the separator element can therefore basically be determined in two different ways. Of course, a combination can also be provided, for example in order to improve an accuracy in the determination of the reference position. A further improvement enables supplementary use of static mathematical methods, such as regression methods or the like.The ascertainment of a characteristic curve of the separating element 12 is now explained by way of example below. It can be taken into account here that a characteristic of the separating element 12 is nonlinear. For this reason, it is appropriate to use a plurality of positions of the partition member 12. One or more predetermined positions of the separator 12 may be achieved by adjusting a corresponding drive pressure. For this purpose, the pump chamber 11 of the fluid pump 10 is in fluidic connection with the sensing membrane 50, so that at least during the sensing of the force by means of the force sensor 51 in the region of the sensing membrane 50 substantially the same fluid pressure as in the pump chamber 11 is present. In this way, a plurality of operating points can be set discretely or continuously, and the characteristic curve can be determined by means of the control device 102 as a function of the data acquired in this case for the separating element 12, which characteristic curve can be used as a basis for the further intended use of the ophthalmic surgical system 100. For respective positions of the separating element 12, in this way, inter alia, respective pressure differences between the drive fluid in the drive chamber 13 and the treatment fluid in the pump chamber 11 can be determined. In this way, a characteristic curve in the manner of a correction curve can be determined.The evaluation of the data by the control device 102 can comprise the determination of a respective pressure difference between the respective drive pressure and the fluid pressure of the treatment fluid 3 respectively detected for this purpose with respect to a respective position of the separating element 12 in order to determine a dependence of a pressure difference caused by the elastic separating element 12 on the drive pressure and the respective fluid pressure of the treatment fluid 3 on the respective position. For this purpose, it can additionally be provided that the control device 102 takes into account mathematical methods, in particular regression methods or other statistical methods, in order to be able to determine the dependence as reliably and accurately as possible.On the basis of the dependence determined in this way, the control of the ophthalmic surgical system 100 can then take place in the intended operation. The calibration data for the force sensor 51 determined in this way and the characteristic curves for the separating elements 12, 22, 32, 42 can be stored in the control device 102 so that they are available for the intended operation of the ophthalmic surgical system 100. The invention can achieve, overall, that an improved, more precise control for the conveying of the treatment fluid 3 can be realized.The exemplary embodiments serve exclusively to explain the invention and are not intended to limit it.List of reference characters1 Console 2 Treatment fluid source 3 Treatment fluid 4 Cassette 8 Irrigation fluid flow path 9 Aspiration fluid flow path 10 Fluid pump 11 Pump chamber 12 Separating element 13 Drive chamber 14 Edge 15 Inlet valve 16 Outlet valve 17 Drive fluid source 18 Proportional valve 19 Displacement sensor 20 Fluid pump 21 Pump chamber 22 Separating element 23 Drive chamber 24 Edge 25 Inlet valve 26 Outlet valve 27 Drive fluid source 28 Proportional valve 29 Displacement sensor 30 Fluid pump 31 Pump chamber 32 Separating element 33 Drive chamber 34 Edge 35 Inlet valve 36 Outlet valve 37 Drive fluid source 38 Proportional valve 39 Displacement sensor 40 Fluid pump 41 Pump chamber 42 Separating element 43 Drive chamber 47 Drive fluid source 48 Proportional valve 50 Detection membrane 51 Force sensor 52 Detection sensor 53 Aspiration fluid collection container 60 Flow chart 61 Step 62 Step 63 Step 64 Step 65 Step 66 Step 70, 71 Graph 72 Fluidic connection element 81 Partial path 82 Partial path 83 Partial path 84 Partial path 91 Partial path 93 Partial path 100 System 101 Cassette holder 102 Control deviceReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2016 201 297 B3 [0003, 0006]DE 10 2021 124 415 A1

[0024]

Claims

Control device (102) for an ophthalmic surgical system (100), in which an ophthalmic surgical cassette (4) can be inserted into a cassette holder (101) of a console (1) of the ophthalmic surgical system (100), wherein the cassette (4) has at least one fluid pump (10, 20, 30, 40) for conveying a treatment fluid (3) through the cassette (4), for which purpose the at least one fluid pump (10, 20, 30, 40) has a pump chamber (11, 21, 31, 41) for the treatment fluid (3) and a drive chamber (13, 23, 33, 43) for a drive fluid, wherein the pump chamber (11, 21, 31, 41) and the drive chamber (13, 23, 33, 43) are fluidically separated from one another by an elastic separating element (12, 22, 32, 42) which is designed for a pump stroke of the fluid pump (10, 20, 30, 40) between two end positions of the separating element (12, 22, 32, 42), 32, 42), wherein the drive chamber (13, 23, 33, 43) can be fluidically coupled to a drive fluid source (17, 27, 37, 47) of the console (1) when the cassette (4) is inserted into the cassette holder, wherein the drive fluid source (17, 27, 37, 47) is designed to provide the drive fluid, as a function of a drive pressure control signal of the control device (102), at a predefinable drive pressure which can be detected by means of a drive pressure sensor (18, 28, 38, 48) of the console (1), wherein, when the cassette (4) is inserted into the cassette holder (101), a first surface of a detection membrane (50) of the cassette (4) can be mechanically contacted by a force sensor (51) of the console (1), wherein a second surface of the detection membrane (50) contacts the treatment fluid (3) contained in the cassette (4), wherein the control device (102) is designed to be actuated by a force sensor (51) of the console (1), Signals from at least the drive pressure sensor (18, 28, 38, 48), the force sensor (51) and a travel sensor (19, 29, 39, 49) of the console (1) for detecting a position of the separating element (12, 22, 32, 42) in the fluid pump (10, 20, 30, 40) and evaluating it and providing the drive pressure control signal at least partially as a function of the received signals, characterized in that the control device (102) is designed, in the case of the cassette (4) inserted into the cassette holder (101), to provide a first drive pressure control signal for calibrating the force sensor (51) as a function of detecting one of the two end positions of the separating element (12, 22, 32, 42), such that the drive fluid source (17, 27, 37, 47) provides the drive fluid at a constant first drive pressure, in order for the separating element (12, 22, 32, 42) to be moved from a first of the end positions into a second of the end positions, a temporal profile of a sensor signal, preferably at least one force signal of the force sensor (51) or of a path signal of the path sensor (19, 29, 39, 49) during the movement from the first of the end positions into the second of the end positions, to be detected and evaluated in order to determine a reference position of the separating element (12, 22, 32, 42) in the fluid pump (10, 20, 30, 40), in which the drive pressure corresponds to the fluid pressure of the treatment fluid, to determine a path signal of the path sensor (19, 29, 39, 49) corresponding to the reference position as a reference path signal, to detect a first force signal of the force sensor (51) in the reference position, and to calibrate the force sensor (51) as a function of the first force signal and the first drive pressure.Control device according to Claim 1, characterized in that the control device (102) is designed to subsequently provide a second drive pressure control signal, such that the drive fluid source (17, 27, 37, 47) provides the drive fluid at a constant second drive pressure, to record a second force signal of the force sensor (51) at the reference position of the separating element (12, 22, 32, 42) and to calibrate the force sensor (51) as a function of the first and of the second force signal and of the first and of the second drive pressure.Control device according to one of the preceding claims, characterized in that the control device (102) is designed to determine a relative maximum value of the force signal when evaluating the time profile of the force signal and to define the value of the path signal present at the time of the relative maximum value of the force signal as the reference path signal corresponding to the reference position of the separating element (12, 22, 32, 42).Control device according to one of the preceding claims, characterized in that the control device (102) is designed to determine an inflection point when evaluating the time profile of the path signal and to define the value of the path signal present at the time of the inflection point as the reference path signal corresponding to the reference position of the separating element (12, 22, 32, 42).Control device according to one of the preceding claims, characterized in that the control device (102) is designed to determine correction data at least with respect to a dependence of the respective fluid pressure on the respective drive pressure by means of a regression method, taking into account the properties of the separating element (12, 22, 32, 42).Control device according to one of the preceding claims, characterized in that the control device (102) is designed to detect the insertion of the cassette (4) into the console (1) and to calibrate at least the force sensor (51) as a function of the detection of the insertion.Control device according to one of the preceding claims, characterized in that the control device (102) is designed to repeat at least the calibration of the force sensor (51) or the calibration of the displacement sensor (19, 29, 39, 49) at at least one predefined point in time or in the case of at least one predefined event.Control device according to one of the preceding claims, characterized in that the control device (102) is designed to carry out at least the calibration of the force sensor (51) upon initialization of the ophthalmic surgical system (100).Control device according to one of the preceding claims, characterized in that the cassette (4) has a plurality of fluid pumps (10, 20, 30, 40) which are fluidically connected at least partially in parallel or are connected in series, wherein the console (1) has a corresponding displacement sensor (19, 29, 39, 49) in each case for each of the fluid pumps (10, 20, 30, 40), wherein the control device (102) is designed to carry out the calibration of the displacement sensors (19, 29, 39, 49) one after the other in a predeterminable sequence.Console (1) for an ophthalmic surgical system (100) for operating an ophthalmic surgical handpiece, which can be connected to the console (1), wherein the console (1) has at least one cassette holder (101) for arranging an ophthalmic surgical cassette (4), wherein the cassette (4) has at least one fluid pump (10, 20, 30, 40) for conveying a treatment fluid (3) through the cassette (4), for which purpose the at least one fluid pump (10, 20, 30, 40) has a pump chamber (11, 21, 31, 41) for the treatment fluid (3) and a drive chamber (13, 23, 33, 43) for a drive fluid, wherein the pump chamber (11, 21, 31, 41) and the drive chamber (13, 23, 33, 43) are fluidically separated from one another by an elastic separating element (12, 22, 32, 42), wherein the console (1) has at least one with the drive chamber (13, 23, 33, 43), 43) of the cassette (4) fluidically couplable drive fluid source (17, 27, 37, 47), at least one drive pressure sensor (18, 28, 38, 48) for detecting a drive pressure of the drive fluid source (17, 27, 37, 47), at least one travel sensor (19, 29, 39, 49) for detecting a position of the separating element (12, 22, 32, 42) in the fluid pump (10, 20, 30, 40), at least one force sensor (51) for mechanically contacting a detection membrane (50) of the cassette (4), wherein the detection membrane (50) contacts the treatment fluid (3) contained in the cassette (4), and a control device (102) at least for controlling the drive fluid source (17, 27, 37, 47), wherein the control device (102) is designed to at least signals of the at least one drive pressure sensor (18, 28, 38, 48) of the at least one travel sensor (19, 29, 39, 48), 49 ) and the at least one force sensor (51), and to evaluate them and, depending on the evaluation, to provide a drive pressure control signal for controlling the drive pressure to be provided by the drive fluid source (17, 27, 37, 47), characterized in that the control device (102) is designed according to one of the preceding claims.Ophthalmic surgical system (100), comprising at least: - an ophthalmic surgical handpiece, - an ophthalmic surgical cassette (4), wherein the cassette (4) comprises at least one fluid pump (10, 20, 30, 40) for conveying a treatment fluid (3) through the cassette (4), for which purpose the at least one fluid pump (10, 20, 30, 40) comprises a pump chamber (11, 21, 31, 41) for the treatment fluid (3) and a drive chamber (13, 23, 33, 43) for a drive fluid, which drive chamber can be fluidically coupled to a drive fluid source (17, 27, 37, 47) of a console (1), wherein the pump chamber (11, 21, 31, 41) and the drive chamber (13, 23, 33, 43) are fluidically separated from one another by an elastic separating element (12, 22, 32, 42), and wherein the cassette (4) has a detection membrane (50) which contacts the treatment fluid (3) contained in the cassette (4) and can be mechanically contacted by a force sensor (51) of the console (1), and - a console (1) having a cassette receptacle (101) for arranging the ophthalmic surgical cassette (4), characterized in that the console (1) is designed according to claim 10.

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