Method for operating a fluid pump and ophthalmic surgical system therewith

Abstract

Method for operating a fluid pump (10, 20, 30, 40) of an ophthalmic surgical system (100) designed to convey a treatment fluid (3), by means of which the treatment fluid (3) is conveyed during operation of the system (100), wherein the fluid pump (10, 20, 30, 40) has a pump chamber (11, 21, 31, 41) and a drive chamber (13, 23, 33, 43) separated from the pump chamber (11, 21, 31, 41) by means of an elastic separating element (12, 22, 32, 42), wherein the drive chamber (13, 23, 33, 43) is supplied with a drive fluid (17, 27, 37, 47) and a position of the elastic separating element (12, 22, 32, 42) is detected by means of a position sensor (19, 29, 39, 49), characterized in that - the drive fluid (17, 27, 37, 47) is subjected to a first drive pressure, at which the elastic separating element (12, 22, 32, 42) assumes a first position (61), - a pressure of the treatment fluid (3) present in the first position of the separating element (12, 22, 32, 42) is detected (62) by means of a detection sensor (52) of the ophthalmic surgical system (100), - the drive fluid (17, 27, 37, 47) is subjected to at least one further drive pressure (17, 27, 37, 47) different from the first drive pressure, at which the separating element (12, 22, 32, 42) assumes a further position (63) different from the first position, - the at least one further position of the separating element (12, 22, 32, 42) caused by the at least one further drive pressure and a further pressure of the treatment fluid (3) present in this further position are detected (64), and - the pressures of the treatment fluid (3) present at the respective positions and the drive pressures present at the respective positions are taken into account when operating the fluid pump (10, 20, 30, 40) (65).

Description

[0001] The invention relates to a method for operating a fluid pump of an ophthalmic surgical system designed to convey a treatment fluid, by means of which the treatment fluid is conveyed during operation of the system, wherein the fluid pump has a pump chamber and a drive chamber separated from the pump chamber by means of an elastic separating element, wherein the drive chamber is acted upon by a drive fluid and a position of the elastic separating element is detected by means of a position sensor.The invention further comprises a method for operating an ophthalmic surgical system for treating an eye, wherein the ophthalmic surgical system has a console for receiving a treatment fluid, a cassette insertable into the console for conveying the treatment fluid to a surgical instrument for treating the eye, and at least one fluid pump for conveying the treatment fluid during operation of the system. The fluid pump has a pump chamber and a drive chamber separated from the pump chamber by an elastic separating element. The drive chamber is supplied with a drive fluid, and a position of the elastic separating element is detected by a position sensor. The console has the drive chamber and the cassette has the pump chamber with the separating element. Finally, the invention also relates to an ophthalmic surgical system for treating an eye.

[0002] Ophthalmic surgical systems, methods for their operation, and methods for operating fluid pumps are known in the prior art, so that separate written evidence is fundamentally unnecessary in this regard. Various surgical techniques are known for the treatment of opacities of the lens of the eye, also known in medicine as cataracts. The most common is phacoemulsification, in which a thin hollow needle is inserted into the capsular bag containing the lens and stimulated to produce ultrasonic vibrations. The vibrating hollow needle can be used to emulsify the lens, with any released lens particles being suctioned away via an aspiration line using a pump. A rinsing fluid, also called irrigation fluid, is supplied. The lens particles are suctioned away together with the fluid as the aspiration fluid.Once the lens is completely emulsified and removed, a new artificial lens can be inserted into the emptied capsular bag. This allows the patient to regain good vision.

[0003] An advanced ophthalmic surgical system that has proven particularly suitable for phacoemulsification is disclosed, for example, in DE 10 2016 201 297 B3. This system utilizes two fluid pumps connected in parallel for irrigation and aspiration. Each fluid pump has a pump chamber and a drive chamber separated from the pump chamber by an elastic separating element. For the fluid pump's intended operation, the drive chamber is supplied with a drive fluid, the drive pressure of which is varied to execute each pump stroke. As a result, the position of the elastic separating element changes depending on this, which has a corresponding effect on the pump chamber. The pump chamber is supplied with the respective treatment fluid, for example, the irrigation fluid, the aspiration fluid, or the like.The conveying effect can then be achieved by appropriately controlling an inlet and an outlet valve of the fluid pump.

[0004] The position of the elastic separating element is detected by a position sensor assigned to the respective fluid pump. A control device of the ophthalmic surgical system controls the function of the fluid pump depending at least on a sensor signal from the position sensor and a drive pressure signal provided by a drive pressure sensor. The control device can additionally control the inlet and outlet valves accordingly, for example.

[0005] By alternately operating the two fluid pumps connected in parallel, a flow rate with very low fluctuations can be achieved during surgery. This allows for a nearly constant intraocular pressure in the capsular bag. As long as sufficient irrigation fluid can be supplied, the system can be operated with virtually no interruption in the irrigation fluid flow, even during a very long operation.

[0006] The elastic separating element of each of the fluid pumps is thus not actuated by a plunger or rod, but rather by the drive fluid. This allows for virtually jerk-free and very fast actuation. At the same time, the fluid pump implemented in this way proves to be very low-maintenance and reliable. The ophthalmic surgical system disclosed in DE 10 2016 201 297 B3 is therefore particularly suitable for procedures that require a reaction in the event of a blockage of the needle tip of the hollow needle or the suction opening. Such a condition 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 intraocular pressure can be kept almost constant even in the event of such disruptions during operation.

[0007] For the intended operation of the ophthalmic surgical system, it is desirable to keep the intraocular pressure, particularly in the capsular bag, as constant as possible by regulating the pressure of the irrigation fluid and the vacuum of the aspiration fluid. To achieve this, it is desirable to know the pressure of the treatment fluid as precisely as possible so that this pressure can be regulated accordingly. In the fluid pump described above, the pressure of the treatment fluid depends on the drive pressure of the drive fluid. Furthermore, there is also a dependence on the properties of the separating element. Due to component variations and tolerances, as well as aging effects due to storage or the like, deviations in the properties occur between different separating elements. These deviations can, for example, relate to a dependence of a pressure difference caused by the separating element on a respective position of the separating element.Such a deviation may be above a desired accuracy range that is appropriate for controlling intraocular pressure.

[0008] It is therefore the object of the invention to improve the operation of an ophthalmic surgical system and an ophthalmic surgical system in such a way that a control with respect to the treatment fluid can be realized more precisely.

[0009] As a solution, the invention proposes a method for operating a fluid pump of an ophthalmic surgical system designed to convey the treatment fluid, a method for operating an ophthalmic surgical system for treating an eye, and an ophthalmic surgical system for treating an eye according to the independent claims.

[0010] Advantageous further training results from features of the dependent claims.

[0011] With regard to a generic method for operating a fluid pump of an ophthalmic surgical system designed to convey a treatment fluid, the invention proposes in particular that the drive fluid is subjected to a first drive pressure, at which the elastic separating element assumes a first position, a pressure of the treatment fluid present in the first position of the separating element is detected by means of a detection sensor of the ophthalmic surgical system, the drive fluid is subjected to at least one further drive pressure different from the first drive pressure, at which the separating element assumes a further position different from the first position, the at least one further position of the separating element caused by the at least one further drive pressure and a further pressure of the treatment fluid present in this further position are detected,and the pressures of the treatment fluid at the respective positions and the drive pressures at the respective positions are taken into account when operating the fluid pump.

[0012] With regard to a generic method for operating an ophthalmic surgical system for treating an eye, the invention proposes in particular that the method of the invention is started after the cassette has been inserted into the console.

[0013] With regard to a generic ophthalmic surgical system for treating an eye, the invention proposes in particular that the system comprises at least: - a console for receiving a treatment fluid container for receiving a treatment fluid, - a cassette that can be inserted into the console to control the treatment fluid to a surgical instrument for treating the eye - at least one fluid pump for conveying the treatment fluid during operation of the system, wherein the fluid pump has a pump chamber and a drive chamber separated from the pump chamber by means of an elastic separating element, wherein the drive chamber can be supplied with a drive fluid and a position of the elastic separating element can be detected by means of a position sensor of the ophthalmic surgical system, wherein the ophthalmic surgical system is designed, - to apply a first drive pressure to the drive fluid, at which the elastic separating element assumes a first position, - to detect the pressure of the treatment fluid present in the first position of the separating element by means of a detection sensor of the ophthalmic surgical system, - to apply at least one further drive pressure to the drive fluid which is different from the first drive pressure and at which the separating element assumes a further position which is different from the first position, - to detect the at least one further position of the separating element caused by the at least one further drive pressure and a further pressure of the treatment fluid present in this further position, and - the pressures of the treatment fluid at the respective positions and the drive pressures at the respective positions must be taken into account when operating the fluid pump.

[0014] In particular, the ophthalmic surgical system according to the invention is suitable for carrying out the methods according to the invention.

[0015] The invention is based, among other things, on the idea that the function of the control system for the treatment fluid can be improved if the properties of the fluid pump are better and more precisely known. This applies in particular to the properties of the separating element. Since fluid pumps are generally used to pump a medical treatment fluid, pressure sensors for the treatment fluid are often not provided for reasons of hygiene and sustainability. A statement about the pressure of the treatment fluid can therefore only be made indirectly, i.e., depending on the drive pressure of the drive fluid. The actual pressure of the treatment fluid is not measured. It is therefore desirable to be able to take the specific properties of the separating element into account. The method according to the invention makes it possible to implement the control function more precisely and thus more purposefully.

[0016] For this purpose, at least two different positions are assumed by setting at least two different drive pressures of the drive fluid. These positions can be detected by the position sensor. A detection sensor of the ophthalmic surgical system can be used to detect a pressure of the treatment fluid for each of these at least two drive pressures. The data obtained in this way can be evaluated, in particular, by the control device, so that a behavior of the separating element can be determined depending on a respective position. Preferably, the behavior relates to the separating element being able to result in a pressure in the treatment fluid that is lower in magnitude than the respective drive pressure, depending on its respective position.

[0017] Knowledge of this dependency allows for improved control of the treatment fluid, for example, the irrigation fluid or the aspiration fluid. Implementing the invention does not require any expensive additional measures. For example, the detection sensor can be provided by an element required for redundancy reasons, as will be explained below. The invention thus makes it possible to perform the method individually for each fluid pump, even when multiple fluid pumps are connected in parallel, so that the method implementations according to the invention and also the ophthalmic surgical system according to the invention enable improved operation.

[0018] The separating element, which separates the pump chamber from the drive chamber, can be designed in the form of an elastic membrane, a film, or the like. Preferably, a peripheral edge of the separating element can be firmly arranged or fixed in the fluid pump. This allows the separating element to fluidically separate the pump chamber from the drive chamber, in particular in such a way that the sterility of the treatment fluid is not compromised.

[0019] For example, it is possible for the fluid pump to be at least partially enclosed by the cassette and at least partially enclosed by the console. This allows the cassette to be detachably connected to the console, with the fluid pump being completed in the connected state. The cassette can thus be used to provide a replacement part which can be used to ensure the sterility of the ophthalmic surgical system for a particular operation on the eye, in particular with regard to the treatment fluid. This makes it possible to only pass the treatment fluid through the cassette, meaning that the treatment fluid does not need to flow through the console. This means that after each use of the ophthalmic surgical system, the sterility of the ophthalmic surgical system can be easily restored at any time by replacing the cassette.Of course, it is preferably provided that the cassette, when connected to the console, is connected to the console in a fluid-tight manner, so that the respective drive chamber of the respective fluid pump is fluid-tightly adjacent to the separating element in order to enable the fluid pump to operate as intended. For example, it can thus be provided that the cassette, in particular also the fluid pump or the cassette-side elements of the fluid pump, in particular the respective separating element, can be made of a suitable plastic or comparable material.

[0020] The drive fluid, which serves to pressurize the drive chamber in order to be able to drive the fluid pump, can be, for example, a liquid such as water, oil, mixtures of liquids and / or the like, as well as a gas, for example air, nitrogen, a noble gas, mixtures of gases and / or the like, as well as a combination thereof.

[0021] The drive fluid can preferably be provided exclusively via the console. For this purpose, a drive pressure sensor can be provided in the console, for example, by means of which the drive pressure of the drive fluid can be detected. Because the drive pressure sensor can be located on the console side, it does not need to meet any special sterility requirements because it does not need to come into contact with the treatment fluid. This allows the drive pressure sensor to be selected with optimized detection functionality.

[0022] Furthermore, a position sensor is preferably provided, which serves to detect the position of the elastic separating element. The position sensor can be provided either in the console or in the cassette. The position sensor can detect the position of the separating element preferably without contact. For this purpose, it can have, for example, an inductive, capacitive, or optical sensor element. The position sensor can communicate with the control device of the ophthalmic surgical system wirelessly, for example via radio or via a communication line. The position sensor can be designed, for example, as a transponder, in particular as a passive transponder, whereby a cassette-side power supply can be saved or reduced if the position sensor is provided in the console.

[0023] Within the scope of the method, it is provided that the drive fluid is subjected to a first drive pressure, at which the elastic separating element assumes a first position. This position is preferably a position of the separating element in which a pressure difference caused by the separating element is as small as possible. This means that in this first position, the drive pressure can be selected such that the separating element is essentially or almost in a relaxed or unstressed state. In this state of the separating element, a pressure difference between the drive chamber and the pump chamber can preferably be largely neglected. In this first position of the separating element, an existing pressure of the treatment fluid can be detected by means of a detection sensor of the ophthalmic surgical system.In principle, the detection sensor can of course be designed as a pressure sensor or the like, which allows the pressure of the treatment fluid to be reliably detected. For this purpose, the detection sensor can be arranged at least partially on the cassette side to allow access to the treatment fluid. The detection sensor can therefore be arranged at least partially on the cassette side. However, it can also be arranged at least partially on the console side, as will be explained below.

[0024] The drive fluid is then, preferably subsequently, subjected to at least one further drive pressure, different from the first, at which the separating element assumes a further position different from the first position. At this further or second drive pressure, different from the first drive pressure, the separating element assumes a further or second position. In this further or second position, an existing further pressure of the treatment fluid is detected by the detection sensor. Preferably, the respective positions of the separating element are also detected by the position sensor.

[0025] The pressures of the treatment fluid present at the respective positions and the drive pressures present at the respective positions are then taken into account when operating the fluid pump. Operating the fluid pump can comprise evaluating the detected pressures and positions, wherein specific dependencies of the aforementioned variables applicable to the respective fluid pump can then be determined. Preferably, during operation, a dependency can be determined in which a pressure difference caused by the separating element is represented by its respective position. This dependency can then be used to control the ophthalmic surgical system, in particular the at least one fluid pump. The evaluation can be carried out at least partially by means of the control device of the ophthalmic surgical system.

[0026] To reach the first position of the separating element, the separating element can preferably be brought into a rest position. The rest position can be the relaxed position of the separating element, in which it transmits essentially no force between the drive chamber and the pump chamber, i.e., between the drive fluid and the treatment fluid in the respective chamber of the fluid pump. Furthermore, it can be provided that to reach at least one further position of the separating element, the separating element is deflected to its maximum extent. This configuration makes it possible to record the behavior of the fluid pump during an entire pumping stroke.

[0027] Of course, the method according to the invention is not limited to using only two different drive pressures or positions of the separating element, for which corresponding pressures of the treatment fluid are recorded. Depending on the requirements and properties of the fluid pump, several different drive pressures or positions of the separating element can of course also be provided, for each of which a respective pressure of the treatment fluid is recorded. This can further improve the operation of the fluid pump. The selection of the different drive pressures or positions of the separating element does not have to be equidistant. Depending on requirements, the difference between two consecutive drive pressures or positions of the separating element can vary.

[0028] According to a further development, it is proposed that a controllable adjusting device be arranged in a flow path for the treatment fluid formed between the fluid pump and a surgical instrument, which, upon reaching one of the aforementioned positions, is switched by the separating element into a state that reduces or blocks the flow of the treatment fluid. The adjusting device can be an at least partially separate device or at least partially provided by the ophthalmic surgical system. Preferably, the adjusting device is controlled by means of the control device. The adjusting device makes it possible to control the flow of the treatment fluid. For example, it can be provided that the flow is throttled or blocked while the pressure of the treatment fluid is being detected.

[0029] This configuration makes it possible to improve the detection of the pressure of the treatment fluid. In particular, it can be provided that, upon a transition from the first drive pressure to the further drive pressure, the adjusting device is switched to an at least partially, preferably fully, open state, so that a corresponding change in the position of the separating element can be enabled, and upon reaching the further drive pressure, the adjusting device is switched to the state that reduces or throttles the flow of the treatment fluid, or blocks or obstructs it, so that the corresponding pressure of the treatment fluid can be reliably detected by the detection sensor. For this purpose, the adjusting device can, for example, have a valve that is adjustable by means of a suitable drive. For example, the valve can be actuated by means of an electric solenoid or the like.However, it can also be provided that the adjustment device can be driven pneumatically or hydraulically. The adjustment device can also be included in the cassette. If, for example, a fluid pump for conveying the irrigation fluid and another fluid pump for conveying the aspiration fluid are provided in the cassette, the instrument-side flow paths of the two fluid pumps can be fluidically connected to one another, so that to operate one of the fluid pumps, the other of the fluid pumps, in particular its inlet or outlet valve, can serve as an adjustment device. For this purpose, corresponding valves of the fluid pumps can be actuated, for example. The elements can be controlled at least partially by means of the control device.

[0030] The surgical instrument can be used to treat the eye. It can, for example, be a handpiece for performing phacoemusification. The surgical instrument can, for example, be connected to the ophthalmic surgical system as a separate part or be a component of the ophthalmic surgical system. Preferably, the surgical instrument can be supplied with the treatment fluid via the cassette. For this purpose, the surgical instrument can, for example, be connected directly to the cassette. It can be provided that an irrigation fluid is supplied to the surgical instrument as the treatment fluid and / or that an aspiration fluid is removed from the surgical instrument.

[0031] Furthermore, it is proposed that, for a given position, a respective pressure difference between the respective drive pressure and the correspondingly detected treatment fluid pressure be determined in order to determine the position dependency of a pressure difference caused by the elastic separating element between the respective drive pressure and the respective treatment fluid pressure. This allows a particularly relevant dependency for the control during the calibration of the fluid pump to be determined. The method described above can be used for this purpose.

[0032] It is further proposed that an elastic membrane contacting the treatment fluid be arranged in a flow path formed between the fluid pump and the surgical instrument of the ophthalmic surgical system. Depending on the pressure of the treatment fluid, the elastic membrane exerts a force on a force sensor associated with the membrane to form the detection sensor by means of which the pressure of the treatment fluid is detected. In this way, the pressure of the treatment fluid can be detected without the use of a pressure sensor. Furthermore, this design of the detection sensor allows the force sensor to be arranged on the console side and the membrane on the cassette side, so that the force sensor does not need to come into contact with the treatment fluid. Furthermore, this allows the cassette to be designed very simply to be able to detect the pressure of the treatment fluid.The membrane can, for example, be arranged on a fluid line for the treatment fluid, to which the surgical instrument can also be connected. This puts the membrane in contact with the treatment fluid, so that any deflection of the membrane depends on the pressure of the treatment fluid. This deflection can be detected by the force sensor, which, for example, contacts the membrane, so that the pressure of the treatment fluid can be determined by evaluating the detected force. This design also proves advantageous because the cassette is generally intended as a disposable part for one-time use, thus saving resources, particularly with regard to the force sensor.

[0033] It is further proposed that, at a predetermined drive pressure, a first force is detected by means of the force sensor, the predetermined drive pressure is changed by a predetermined pressure change value, and a second force is detected by means of the force sensor, wherein the predetermined pressure change value is less than approximately 50%, preferably less than approximately 20%, of the predetermined drive pressure. This further development makes it possible to use the detection sensor, which here is formed by the membrane and the force sensor, with high precision, so that it can then be used again to operate the fluid pump. Preferably, too, the separating element is in the region of the relaxed state. This can be achieved, for example, by a fluid line to which the surgical instrument can be connected being open towards its end.However, it can also be provided that the corresponding fluid line can be closed by means of the force sensor.

[0034] Based on the specified drive pressure, the drive pressure can be adjusted by the specified pressure change value, with the force sensor then detecting the force that changes as a function of this change. The function of the force sensor can then be determined from the data obtained in this way. This process can also preferably be carried out at least partially by means of the control device. Even if this process is particularly suitable for use in the relaxed state of the separating element, it is not limited to this. In principle, this process can of course also be carried out with non-relaxed separating elements. However, this has an impact on determining the function of the detection sensor comprising the force sensor and the membrane.The predetermined pressure change value is preferably less than approximately 50%, preferably less than approximately 20%, of the specified drive pressure. This allows the function of the detection sensor to be determined with minor changes in the drive pressure. In particular, it can be achieved that the separating element does not need to leave the relaxed state during this process. The force sensor can be used to implement redundancy with respect to the treatment fluid.

[0035] It is particularly advantageous if the pressure of the treatment fluid can be determined using the force sensor for operational purposes. Because the force sensor does not need to be located in the cassette, the force sensor can be optimized with regard to its force detection functionality. Therefore, it does not need to meet any sterility requirements. By providing the membrane on the cassette, however, sterility with respect to the treatment fluid can be ensured. This allows the pressure of the treatment fluid to be measured in a sterile yet reliable manner.

[0036] It is further proposed that the method according to the invention be carried out during an operation of the fluid pump that differs from its intended operation. Operation can be carried out, for example, when the fluid pump is not in use during the treatment of an eye. For example, the method can be carried out before the start of its intended use, in particular an operation on the eye. However, the method can also be carried out during interruptions in treatment or the like. Furthermore, it can be provided that the calibration is repeated at predetermined time intervals or during predetermined events. Such an event can be, for example, a change of the surgical instrument or the like.

[0037] With regard to a method for operating an ophthalmic surgical system for treating an eye, it is further proposed that the method of the invention for operating the fluid pump be started after the cassette has been inserted into the console. Starting can, for example, occur automatically with the insertion of the cassette. Furthermore, it can also be provided that the method is started by manual actuation by the user of the ophthalmic surgical system. Of course, combinations of these can also be provided.

[0038] The ophthalmic surgical system for treating an eye comprises at least one console for receiving a treatment fluid container for containing a treatment fluid. The treatment fluid container can, for example, be an irrigation fluid container with a sufficiently large capacity for an irrigation fluid so that even a longer operation can be performed without changing the treatment fluid container. The same principle can also be applied to a treatment fluid container used to hold the aspiration fluid. The ophthalmic surgical system further comprises a cassette insertable into the console for directing the treatment fluid to the surgical instrument for treating the eye. The cassette is preferably designed such that the treatment fluid does not come into contact with the console.The cassette can be designed as a disposable component so that after use in an operation on one eye, it can be replaced for a subsequent operation. This makes it easy to ensure sterility. The ophthalmic surgical system further comprises at least one fluid pump for conveying the treatment fluid during normal operation of the system. Preferably, at least one fluid pump is provided for conveying the irrigation fluid and at least one pump is provided for conveying the aspiration fluid. Each fluid pump has a pump chamber and a drive chamber separated from the pump chamber by the elastic separating element. The drive chamber can be pressurized with the drive fluid, which can be supplied to the drive chamber on the console side. For this purpose, a drive fluid source can be provided which is adjustable with regard to the drive pressure.The drive pressure can be measured using a drive pressure sensor, which can also be located on the console side. This fluid pump design allows the treatment fluid in the cassette to be routed essentially separately from the console. Only connections for supplying the treatment fluid to the fluid pump and for discharging the treatment fluid from the fluid pump need to be provided on the cassette.

[0039] The ophthalmic surgical system further comprises a position sensor for detecting the position of the elastic separating element. The position sensor is preferably arranged on the cassette side, so that the pump chamber, the elastic separating element, and the position sensor can form a unit in the cassette. The position sensor can preferably be wirelessly coupled to the console, in particular to the control device of the ophthalmic surgical system, which is preferably arranged in the console.

[0040] The console can also include the control device, which can implement the necessary functions for proper operation and, in particular, for the process control according to the invention. For this purpose, the control device can be connected to the corresponding sensors and drive or control elements.

[0041] The advantages and effects stated for the method according to the invention naturally also apply equally to the ophthalmic surgical system according to the invention and the method for its operation, and vice versa. In principle, device features can therefore also be formulated as method features, or vice versa.

[0042] Further features of the invention emerge from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as 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 respective combination specified, but also in other combinations without departing from the scope of the invention. Thus, embodiments are also to be considered encompassed and disclosed by the invention that are not explicitly shown and explained in the figures, but which emerge and can be produced through separate combinations of features from the explained embodiments.

[0043] The figures show: Fig. 1 A schematic representation of a first embodiment of the ophthalmic surgical system according to the invention, Fig. 2 a schematic perspective view of a console of the system according to Fig. 1, Fig. 3 a schematic plan view of a connection side of a cassette for the system according to Fig. 1, Fig. 4 a schematic representation of a second embodiment of the system according to the invention, Fig. 5 a schematic representation of a flow diagram for a process according to the invention, Fig. 6 a schematic diagram of a fluid pump calibration according to Fig. 4 determined dependence of a pressure difference at a separating element on a position of the separating element, and Fig. 7 a schematic representation of a first fluid pump with a first detection sensor according to the first embodiment of the ophthalmic surgical system according to the invention.

[0044] Fig. 1 shows a schematic representation of a first embodiment of an ophthalmic surgical system 100 according to the invention. The system 100 has a console 1, to which an irrigation fluid container 2 containing an irrigation fluid 3 is coupled. Furthermore, the system 100 has a cassette 4, which can be inserted into the console 1. In addition to conveying the irrigation fluid 3 to a surgical instrument 5, which is used for the phacoemulsification of a lens 7 of an eye 6 as a treatment, the cassette 4 also serves to drain any aspiration fluid generated during this treatment from a treatment area of ​​the eye 6. The surgical instrument 5 is designed as a handpiece and is used for the phacoemulsification of the lens 7 of the eye 6. Fig. 2 shows a schematic perspective view of the console 1 without the cassette 4. Fig. 3 shows a schematic plan view of a connection side of the cassette 4 for connecting to the console 1.

[0045] The system 100 further comprises an irrigation fluid flow path 8 extending from the irrigation fluid container 2 via the cassette 4 to the surgical instrument 5. Furthermore, the system 100 comprises a first fluid pump 10 with a first pump chamber 11 and a first drive chamber 13 separated therefrom by a first elastic separating element 12. The first elastic separating element 12 has an edge 14 by means of which it is fixedly arranged in the fluid pump 10.

[0046] 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 the valve state of the inlet valve 15. Furthermore, it can be discharged from the pump chamber 11 again via an outlet valve 16, depending on the valve state of the outlet valve. The first drive chamber 13 can be supplied with a first drive fluid 17, which can be supplied via a proportional valve 18 arranged in the console 1. Depending on a differential pressure between the first drive fluid 17 in the first drive chamber 13 and the irrigation fluid 3 as treatment fluid in the first pump chamber 11, an elastic deformation or deflection of the first elastic separating element 12 occurs. The pressure in the first drive chamber 13 is greater than the pressure in the first pump chamber 11.When the inlet valve 15 is closed and the outlet valve 16 is open, the irrigation fluid 3 can flow out of the first pump chamber 11 into a partial path 83 connected to the outlet valve.

[0047] The position of the first elastic separating element 12 can be detected by a first position sensor 19, which is arranged outside the first fluid pump 10, for example, in the console 1. The first position sensor 19 can be designed, for example, as an inductive or capacitive displacement sensor.

[0048] As from Fig. As can be seen in Figure 1, the drive chamber 13 is arranged in the console 1, and the pump chamber 11 with the separating element 12 is arranged in the cassette 4. Thus, by arranging the cassette 4 in the console 1, the fluid pump 10 is completed.

[0049] Out of Fig. 1 further shows that a second fluid pump 20 is connected in parallel to the fluid pump 10. The fluid pump 20 is configured in the same way as 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 sub-path 81 is connected to the first inlet valve 15, and the second sub-path 82 is connected to a second inlet valve 25 of the second fluid pump 20.

[0050] The second fluid pump 20 has a second pump chamber 21 and a second drive chamber 23 separated therefrom by a second elastic separating element 22. The separating element 22 has a second edge 24 that is fixedly mounted in the second fluid pump 20. The second drive chamber 23 can be supplied with a second drive fluid 27 via a second proportional valve 28 arranged in the console 1. The position of the separating element 22 can be detected by a position sensor 29. The irrigation fluid 3 can leave the second pump chamber 21 again into the partial path 84 via a second outlet valve 26. 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 fed to the instrument 5.

[0051] In an area of ​​the fluid connection between sub-path 83 and sub-path 84, for example, in the subsequent irrigation fluid flow path 8, an elastic membrane 50 is formed, which can contact the irrigation fluid 3. The membrane 50 is arranged on the cassette 4. The membrane 50 is contacted by a force sensor 51, which in turn is arranged in the console 1. The membrane 50, in conjunction with the force sensor 51, forms a detection sensor 52.

[0052] During the crushing of the eye lens 7, small lens particles are released, which can be suctioned away together with the supplied 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, two additional fluid pumps 30, 40 connected in parallel can be provided, which are essentially designed in a similar way 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 is also divided into two partial paths 91, 92, which are connected via respective inlet valves 35, 45 to the respective fluid pumps 30, 40, specifically here to the respective pump chambers 31, 41. Here, too, the pump chambers 31, 41 are separated from the respective drive chambers 33, 43 via respective elastic separating elements 32, 42.The separating elements 32, 42 have respective edges 34, 44, which are 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 connected partial paths 93, 94. A third drive fluid 37 can be guided to the third drive chamber 33 by means of a third proportional valve 38. Correspondingly, a fourth drive fluid 47 can be guided to a fourth drive chamber 43 by means of a fourth proportional valve 48. 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 position sensors 39, 49. The two fluid pumps 30, 40 are also operated alternately in the present case, like the fluid pumps 10, 20.

[0053] Fig. 4 shows a schematic representation of a single fluid pump 10 of a further embodiment, which basically has the structure of the fluid pump 10 according to Fig. 1, as already explained for the first embodiment, which is why reference is made to the relevant explanations. In contrast to the first embodiment, the detection sensor 52 in this embodiment is connected to an adjustment device 54, which in this case is formed by an electrically actuated shut-off valve. The adjustment device 54 is arranged downstream of the surgical instrument 5.

[0054] Based on Fig. 4, the calibration of the fluid pump 10 will be explained below, which also applies to the fluid pumps 10 to 40 of the first embodiment according to Fig. 1 apply.

[0055] Each of the fluid pumps 10 to 40 serves to pump the respective treatment fluid, which in this case is the irrigation fluid 3 or the aspiration fluid. It has been shown that the properties of the fluid pumps 10 to 40 depend, among other things, on the respective separating elements 12 to 42, whose mechanical behavior can vary greatly from fluid pump to fluid pump. However, knowledge of the properties of the fluid pumps 10 to 40 is necessary for the most precise control of the supply of irrigation fluid to the instrument 5 and the most precise removal of aspiration fluid. Precise control should, among other things, ensure that the intraocular pressure, particularly in a capsular bag, remains as constant as possible during treatment so that the capsular bag, which holds the lens to be removed, is subjected to as little stress as possible. This can be achieved by operating the respective fluid pumps 10 to 40.

[0056] To operate the fluid pump 10 according to Fig. 4, the process is carried out as shown in the schematic flow diagram 60 according to Fig. 5 is provided. In a first step 61, the drive fluid 17 is adjusted by means of the proportional valve 18 within the drive chamber 13 to a predetermined first drive pressure, at which the elastic separating element 12 assumes a first position. The first position is detected by the position sensor 19. A pressure of the treatment fluid, here the irrigation fluid 3, present in the first position of the separating element 12 is detected in a second step 62 by means of a detection sensor 52 of the ophthalmic surgical system 100. Subsequently, in a third step 63, the drive fluid 17 is subjected to a further drive pressure different from the first drive pressure via the proportional valve 18, at which further position the separating element 12 assumes a different position from the first position, which is also detected by the detection sensor 52.The further position of the separating element 12 caused by the further drive pressure and a further pressure of the treatment fluid present in this further position are recorded in a third step 64. The data recorded here are transmitted to a control device (not shown) of the ophthalmic surgical system 100, which takes into account the pressures of the treatment fluid present in the respective positions and the drive pressures present in the respective positions when operating the fluid pump 10 in a fifth step 65.

[0057] Depending on requirements, a plurality of different drive pressures can be set to detect respective positions of the separating element 12 and respective pressures of the treatment fluid. Preferably, one position of the separating element 12 is a rest position. Another position of the separating element 12 can be a position in which the separating element 12 is maximally deflected. This allows for complete calibration of the fluid pump 10 across the entire stroke range.

[0058] With the adjustment device 54, the flow of the treatment fluid can be blocked when the separating element 12 reaches a respective aforementioned position. Blocking the flow can be provided, for example, for a predetermined short period of time, for example, less than approximately 1.5 seconds, preferably less than approximately 0.9 seconds, so that the respective sensor values ​​can be reliably recorded.

[0059] The evaluation of the data can include determining a respective pressure difference between the respective drive pressure and the correspondingly detected pressure of the treatment fluid for a respective position of the separating element 12 in order to determine a dependency of a pressure difference caused by the elastic separating element 12 between the drive pressure and the respective pressure of the treatment fluid on the position. For this purpose, it can be provided that mathematical methods, in particular regression methods or statistical evaluation methods, are taken into account in order to be able to determine the dependency as reliably and accurately as possible. Based on the dependency determined in this way, the control can then take place during the intended operation of the ophthalmic surgical system 100. An example of such an evaluation is shown in Fig. 6 is shown in a schematic diagram. In Fig. 6, an abscissa is assigned to an electrical voltage that the position sensor 19 provides depending on the detected position of the separating element 12. An ordinate is assigned to the pressure difference at the separating element 12. A graph 56 shows the dependence of the pressure difference on the electrical voltage of the position sensor 19. Fig. 6 shows that the pressure difference is also comparatively small for small deflections or positions of the separating element 12. This corresponds to an electrical voltage of the position sensor 19 that is less than approximately 3 V. From an electrical voltage of approximately 3 V, however, the pressure difference increases significantly. The dependency determined during operation can now be used for precise control during the intended operation of the ophthalmic surgical system 100. The curve determined in this way can be stored in the control device so that it is available for implementing the control functionality. Overall, the invention can achieve the result that the method can be used to implement improved, more precise control for the delivery of the treatment fluid.

[0060] Fig. 7 shows a schematic representation of the position sensor 19 according to Fig. 1 or according to Fig. 4. The position sensor 19 is coupled to the separating element 12 via a coupling 55. The coupling 55 can be implemented, for example, using an electric or magnetic field. As a result, the position sensor 19 can provide an electrical voltage as a sensor signal depending on the respective position of the separating element 12, as already described with reference to Fig. 6. In principle, any method of position detection, preferably contactless, can of course be provided here.

[0061] In order to operate the fluid pumps 10, 20, 30, 40 without the adjusting device 54 in Fig. 4, it can be provided that instead of the surgical instrument 5, a fluidic short circuit is connected, which is removed again after the above-mentioned process steps. As a result, when operating the fluid pumps 10, 20, the inlet valves 35, 45 in the aspiration fluid flow path 9 can take over the function of the adjustment device 54. When operating the fluid pumps 30, 40, the outlet valves 16, 26 can take over the function of the adjustment device 54. As a result, even for a complex ophthalmic surgical system 100, as described with reference to Fig. As shown in Figure 1, the method according to the invention can be implemented for all fluid pumps. Due to the fluidic short circuit, a single detection sensor 52 is sufficient.

[0062] Furthermore, it can be provided that the detection sensor 52 is also calibrated. This is particularly advantageous in this case because the membrane 50 is also replaced when the cassette 4 is replaced. This means that the combination of membrane 50 and force sensor 51 forming the detection sensor 52 is also changed when the cassette 4 is replaced.

[0063] In order to be able to take the resulting changes into account, it can be provided that, at a predetermined drive pressure, a first force is detected by means of the force sensor 51, the predetermined drive pressure is changed by a predetermined pressure change value, and a second force is detected by means of the force sensor 51. The pressure change value is preferably selected to be less than 50%, preferably less than 20%, of the predetermined drive pressure. For the purpose of operation, the pressure of the treatment fluid is determined by means of the force sensor 51. For example, a compensation factor for the detection sensor 52 can be determined, by means of which a detected force of the force sensor 51 can be assigned to a drive pressure.

[0064] The embodiments serve solely to explain the invention and are not intended to limit it. List of reference symbols 1 console 2 irrigation fluid containers 3 Irrigation fluid 4 cassettes 5 surgical instrument 6 Eye 7 eye lens 8 Irrigation fluid flow path 9 Aspiration flow path 10 Fluid pump 11 Pump chamber 12 Separator 13 Drive chamber 14 edge 15 Inlet valve 16 Exhaust valve 17 Drive fluid 18 Proportional valve 19 Position sensor 20 Fluid pump 21 Pump chamber 22 Separator 23 Drive chamber 24 Rand 25 Inlet valve 26 Exhaust valve 27 Drive fluid 28 Proportional valve 29 Position sensor 30 Fluid pump 31 Pump chamber 32 Separator 33 Drive chamber 34 rand 35 Inlet valve 36 Exhaust valve 37 Drive fluid 38 proportional valves 39 Position sensor 41 Pump chamber 42 Separator 43 Drive chamber 44 rand 45 Inlet valve 46 Exhaust valve 47 Drive fluid 48 Proportional valve 49 Position sensor 50 membrane 51 force sensor 52 detection sensor 53 Aspiration fluid collection containers 54 Adjustment device 55 Coupling 56 Graph 60 Flowchart 61 to 65 steps 81, 82, 83, 84, 91, 92, 93, 94 partial path 100 ophthalmic surgical system

Claims

[1] Method for operating a fluid pump (10, 20, 30, 40) of an ophthalmic surgical system (100) designed to convey a treatment fluid (3), by means of which the treatment fluid (3) is conveyed during operation of the system (100), wherein the fluid pump (10, 20, 30, 40) has a pump chamber (11, 21, 31, 41) and a drive chamber (13, 23, 33, 43) separated from the pump chamber (11, 21, 31, 41) by means of an elastic separating element (12, 22, 32, 42), wherein the drive chamber (13, 23, 33, 43) is supplied with a drive fluid (17, 27, 37, 47) and a position of the elastic separating element (12, 22, 32, 42) is detected by means of a position sensor (19, 29, 39, 49), characterized by , that - the drive fluid (17, 27, 37, 47) is subjected to a first drive pressure, at which the elastic separating element (12, 22, 32, 42) assumes a first position (61), - a pressure of the treatment fluid (3) present in the first position of the separating element (12, 22, 32, 42) is detected (62) by means of a detection sensor (52) of the ophthalmic surgical system (100), - the drive fluid (17, 27, 37, 47) is subjected to at least one further drive pressure (17, 27, 37, 47) different from the first drive pressure, at which the separating element (12, 22, 32, 42) assumes a further position (63) different from the first position, - the at least one further position of the separating element (12, 22, 32, 42) caused by the at least one further drive pressure and a further pressure of the treatment fluid (3) present in this further position are detected (64), and - the pressures of the treatment fluid (3) present at the respective positions and the drive pressures present at the respective positions are taken into account when operating the fluid pump (10, 20, 30, 40) (65). [2] Method according to claim 1, characterized by in that in order to reach the first position of the separating element (12, 22, 32, 42) the separating element (12, 22, 32, 42) is brought into a rest position and / or in order to reach at least one further position of the separating element (12, 22, 32, 42) the separating element (12, 22, 32, 42) is deflected to its maximum. [3] Method according to one of the preceding claims, characterized by in that a controllable adjusting device (16, 26, 35, 45, 54) is arranged in a flow path (8, 9) for the treatment fluid (3) formed between the fluid pump (10, 20, 30, 40) and a surgical instrument (5), which is switched into a state reducing or blocking the flow of the treatment fluid (3) when one of the aforementioned positions is reached by the separating element (12, 22, 32, 42). [4] Method according to one of the preceding claims, characterized bythat for a respective position a respective pressure difference between the respective drive pressure and the pressure of the treatment fluid (3) detected for this purpose is determined in order to determine a dependency of a pressure difference caused by the elastic separating element (12, 22, 32, 42) between the respective drive pressure and the respective pressure of the treatment fluid (3) on the position. [5] Method according to one of the preceding claims, characterized by in that an elastic membrane (50) which contacts the treatment fluid (3) is arranged in a flow path (83, 84, 91, 92) formed between the fluid pump (10, 20, 30, 40) and the surgical instrument (5) of the ophthalmic surgical system (100), which elastic membrane (50) exerts a force on a force sensor (51) associated with the membrane (50) depending on a pressure of the treatment fluid (3) in order to form the detection sensor (52) by means of which the pressure of the treatment fluid (3) is detected. [6] Method according to claim 5, characterized by that at a predetermined drive pressure, a first force is detected by means of the force sensor (51), the predetermined drive pressure is changed by a predetermined pressure change value, and a second force is detected by means of the force sensor (51), wherein the predetermined pressure change value is less than 50%, preferably less than 20%, of the predetermined drive pressure. [7] Method according to claim 5 or 6, characterized by that for the purpose of operation the pressure of the treatment fluid (3) is determined by means of the force sensor (51). [8] Method according to one of the preceding claims, characterized by that the operation of the fluid pump (10, 20, 30, 40) is carried out in a manner different from the intended operation. [9] A method for operating an ophthalmic surgical system (100) for treating an eye (6), wherein the ophthalmic surgical system (100) comprises a console (1) for receiving a treatment fluid container (2) for receiving a treatment fluid (3), a cassette (4) insertable into the console (1) for conveying the treatment fluid (3) to a surgical instrument (5) for treating the eye (6), and at least one fluid pump (10, 20, 30, 40) for conveying the treatment fluid (3) during operation of the system (100), wherein the fluid pump (10, 20, 30, 40) comprises a pump chamber (11, 21, 31, 41) and a drive chamber separated from the pump chamber (11, 21, 31, 41) by means of an elastic separating element (12, 22, 32, 42). (13, 23, 33, 43), wherein the drive chamber (13, 23, 33, 43) is supplied with a drive fluid (17, 27, 37, 47) and a position of the elastic separating element (12, 22, 32, 42) is detected by means of a position sensor (19, 29, 39, 49),wherein the console (1) has the drive chamber (13, 23, 33, 43) and the cassette (4) has the pump chamber (11, 21, 31, 41) with the separating element (12, 22, 32, 42), , characterized by that after inserting the cassette (4) into the console (1), the method according to one of the preceding claims is started. [10] Ophthalmic surgical system (100) for treating an eye (6), comprising at least: - a console (1) for receiving a treatment fluid container (2) for receiving a treatment fluid (3), - a cassette (4) insertable into the console (1) for controlling the treatment fluid (3) to a surgical instrument (5) for treating the eye (5), - at least one fluid pump (10, 20, 30, 40) for conveying the treatment fluid (3) during operation of the system (100), wherein the fluid pump (10, 20, 30, 40) has a pump chamber (11, 21, 31, 41) and a drive chamber (13, 23, 33, 43) separated from the pump chamber (11, 21, 31, 41) by means of an elastic separating element (12, 22, 32, 42), wherein the drive chamber (13, 23, 33, 43) can be supplied with a drive fluid (17, 27, 37, 47) and a position of the elastic separating element (12, 22, 32, 42) can be determined by means of a position sensor (19, 29, 39, 49) of the ophthalmic surgical system (100), wherein the ophthalmic surgical system (100) is designed - to apply a first drive pressure to the drive fluid (17, 27, 37, 47) at which the elastic separating element assumes a first position, - detecting a pressure of the treatment fluid (3) present in the first position of the separating element (12, 22, 32, 42) by means of a detection sensor (52) of the ophthalmic surgical system (100), - to subject the drive fluid (17, 27, 37, 47) to at least one further drive pressure different from the first drive pressure, at which the separating element (12, 22, 32, 42) assumes a further position different from the first position, - to detect the at least one further position of the separating element (12, 22, 32, 42) caused by the at least one further drive pressure and a further pressure of the treatment fluid (3) present in this further position, and - the pressures of the treatment fluid (3) present at the respective positions and the drive pressures present at the respective positions when operating the fluid pump (10, 20, 30, 40) are to be taken into account.

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