FLUID MANAGEMENT IN AN OPHTHALMOLOGICAL APPARATUS

Description

[0001] The invention relates to an ophthalmological device according to the preamble of claim 1 and to a replacement part for an ophthalmological device according to the preamble of claim 10 as well as to an associated method.

[0002] The invention relates to ophthalmic surgical devices. During interventions inside the eye, aspiration is often carried out, i.e. the suctioning away of eye fluid or particles removed during the operation. For example, during cataract surgery, the clouded lens is removed from the eye and replaced with an intraocular lens (IOL). For example, phacoemulsification (liquefaction of the lens nucleus) is performed, in which surgical instruments are inserted into the eye through an incision a few millimeters long in the area where the cornea and sclera transition. A piece of the capsule is removed, and then the lens contents are comminuted and removed, e.g., using an ultrasound device or laser. The lens particles are removed using a suction irrigation system connected to the surgical instrument, which represents a key aspect of the present invention.

[0003] This suction irrigation aspirates the shattered lens nucleus particles and replaces the aspirated material with a fluid infusion, for example, a balanced salt solution (BSS). After removing the old lens nucleus, a folded, elastic replacement lens is inserted into the capsular bag through the opening. The suction irrigation is provided by an ophthalmic device, i.e., a surgical device located in the operating room that is operated by the doctor and / or nurse - usually in conjunction with other functions required for the operation. In addition to the phacoemulsification described above, the same medical devices with suction irrigation functions that this invention treats (or rather,specific embodiments of such devices) are also used in other ophthalmological procedures in which an interocular infusion is often (but not necessarily) carried out together with aspiration, for example in vitrectomy, diathermy, capsulotomy, glaucoma surgery, refractive surgery, femto laser, etc. The documents DE 696 21 562, US 2016 / 045367, WO 02 / 056850, US 2012 / 0215160, US 2014 / 0328697, US 2011 / 0054385, US 2014 / 0323953, US 2014 / 016345, US 6,283,937, US 2011 / 0106004 describe exemplary embodiments of such medical Equipment.

[0004] US 2012 / 215160 discloses an ophthalmic system for interocular pressure stabilization with a pressure sensor located directly in the handpiece near the patient's eye. This pressure, measured directly in the eye, is stabilized by controlling a specially designed actuator in the device.

[0005] US 2014 / 328697 discloses a multi-segment peristaltic pump in a medical cassette, the segments of which are arranged out of phase for ripple compensation.

[0006] US 2011 / 054385 discloses an ophthalmological system with a first irrigation fluid source and a second irrigation fluid source, which second source can be switched on as needed.

[0007] US 2014 / 323953 discloses an ophthalmic surgical system in which a device is provided for at least partially releasing the vacuum pressure.

[0008] US 2014 / 163455 discloses a handpiece for phacoemulsification in which a pump for the irrigation fluid is arranged directly in the housing of the handpiece.

[0009] To ensure sterility, intraocular infections or transmission from patient to patient must be reliably prevented – particularly with regard to the aspirated fluid, which is potentially contaminated. This can be achieved, for example, by replacing an interchangeable insert, usually referred to as a cassette. These cassettes can be disposable, daily, and / or reusable. The cassette contains, in particular, those parts of the suction irrigation system that come into contact with potentially contaminated patient fluid. These parts can specifically include pumps or suction devices, valves, and / or sensors for pressure and negative pressure, air bubbles, flow, etc. Connections to lines to and / or from the patient, as well as connections for waste and / or infusion containers, etc., are also required – preferably mechanically coded to prevent mismatching.are usually part of such an exchangeable cassette, which is at least partially attached to or in the medical device in an exchangeable manner. Documents DE 693 09 757, DE 693 21 264, DE 696 15 507, DE 696 15 633, DE 697 09 192, US 5,163,900, US 5,282,787, US 5,582,601, US 5,800,396, US 5,897,524, US 5,899,674, WO 1987 / 001943, WO 2004 / 108189, or WO 2004 / 110524 show related cassettes.

[0010] Sensors, actuators, electronics, and / or mechanics are preferably housed in the medical device rather than in the replaceable cassette. The cassette therefore only contains those parts of the sensors and actuators that come into contact with potentially contaminated fluid, such as the measuring chamber, membrane, pump or suction devices, pinch points of valves, etc. – i.e., primarily passive parts. The active parts of the sensors and actuators, especially if they represent a significant cost factor, are preferably housed in the medical device.

[0011] For the suction-irrigation function, i.e. for infusion and / or aspiration – or in other words for the supply and removal of fluids in the eye, the surgical device or handpiece used to intervene in the eye is equipped with an aspiration line for suction and an infusion line to replace the fluid that has been suctioned out and / or leaked through the insertion opening. In particular, the eye pressure (IOP = Interocular Pressure) must be kept at least approximately constant during the operation. The eye, or a part of the eye such as the anterior chamber, should neither collapse nor become distended during the procedure. Accordingly, an infusion, i.e., the supply of fluid, takes place parallel to the suction through aspiration.

[0012] In the current state of the art, the physician usually sets the desired infusion pressure during the infusion. This is done using a fixed or motor-adjustable stand for the infusion bottle or infusion bag. Depending on the height difference between the patient and the bottle, a hydrostatic pressure results, which, for example, can be on the order of approximately 30 mbar above atmospheric pressure in the eye during such procedures.

[0013] While such an infusion is easy to implement, it does have its drawbacks. For example, setting the desired infusion pressure is rather static and can only be changed with very limited dynamics. The response to the infusion pressure change is slow. For example, the infusion system can react little or not at all to irregularities during a surgery.

[0014] There are known systems in which compressed air can be injected into the infusion container to set the infusion pressure. However, these are complicated to use, require more complex connection, and carry the risk of loss of sterility. Furthermore, changes in infusion pressure can only be implemented slowly. Pressure reductions require specially long cannulas that extend above the fluid level in the bottle. This solution also allows the use of special bottles that are geometrically compatible with the used cannula length.

[0015] It is an object of the present invention to improve an ophthalmological apparatus or to provide an improved interchangeable cassette for such an apparatus.

[0016] One task is to improve and simplify the infusion into the eye, which takes place, for example, as part of a suction rinse during phacoemulsification.

[0017] A particular objective is to ensure simple, safe, and reliable maintenance of a desired intraocular pressure during a procedure, especially in the event of unplanned incidents. The aim is not to complicate the device's operation and handling, but rather to simplify it. It is also important to reduce potential sources of error during handling and the actual use of the ophthalmic device and / or cassette. Another objective may be to reduce or compensate for adverse parasitic effects in the current state of the art, such as pressure drops in the tubes, pressure reduction caused by air filters in the drip chamber, etc.

[0018] According to the invention, these objects are achieved by the features of the independent claims and / or by features of the dependent claims or these solutions are further developed.

[0019] The present invention relates to an ophthalmological device that provides suction irrigation with an aspiration function and an infusion function. It comprises an aspiration conveying device for the motor-driven removal of fluid from a surgical instrument into a waste container. Thus, active aspiration of fluid from a patient to the waste container is provided by means of a surgical interventional tool, which is not part of this invention. This conveying device can be designed, in particular, in the form of a peristaltic pump or a Venturi aspiration with vacuum suction.

[0020] According to the invention, the device further comprises an infusion conveying device for the motor-driven supply of an infusion medium from an infusion container via an infusion connector and a line to the surgical instrument. Thus, an active infusion is provided with a forced conveyance of the infusion medium from the infusion medium reservoir to a surgical instrument in use on the patient. The infusion medium can, in particular, be an infusion fluid, for example a BSS. For the sake of clarity, the following description generally refers to infusion fluid as the infusion medium, but this is not necessarily restrictive. Alternatively, in a special embodiment, a gas can also serve as the infusion medium.In addition to a gas container, the operating room can also function as an infusion container, especially when air is used as the infusion medium.

[0021] Specifically, the device comprises a control module designed to provide an active infusion controlled with respect to an infusion pressure and / or an infusion volume.

[0022] According to the invention, the infusion conveying device is designed as a peristaltic pump for the active volume conveyance of the infusion medium with a known delivery volume.

[0023] In this case, the fluid-contacting areas of the infusion delivery device and the aspiration delivery device can be configured in a common interchangeable cassette for the device. The device can each have a dedicated infusion drive for the infusion delivery device and, in particular separately, a dedicated aspiration drive for the aspiration delivery device.

[0024] The aspiration conveying device and the infusion conveying device can be of similar design and dimensions—especially identical. This can be particularly advantageous because identical control of both conveying devices also results in similar volume delivery.

[0025] A pressure measuring device with a pressure or force sensor is integrated into the device between the infusion delivery device and the surgical instrument, with which the infusion pressure of the infusion medium in the device can be determined. The pressure measuring device can, for example, be designed with a flexible membrane in the interchangeable cassette and an associated pressure or force sensor in the device. When the cassette is inserted, these two sensors form an operative connection, by means of which the pressure value of the infusion medium in the cassette can be determined. Specifically, the determined infusion pressure can be regulated to a target value with automatic control of the infusion delivery device—for example, using a specially designed control unit in the device.

[0026] Furthermore, a ripple compensation system can be implemented between the infusion delivery device and the surgical instrument. This can be implemented, in particular, as a passive ripple compensation system in the form of a flexible line section in the interchangeable cassette, which compensates for fluctuations in the delivery volume and / or delivery pressure of the infusion delivery device by elastically deforming the flexible line section.

[0027] The ophthalmic device can also be equipped with a motorized height adjustment of the infusion container and a bypass valve for optionally bypassing the infusion delivery system. The bypass valve in the exchangeable cassette can be passive, e.g., designed as a fluid channel squeeze area, and can be mechanically actuated by a valve drive in the device.

[0028] An air bubble sensor can also be installed along a path of the removable cassette through which the infusion fluid is supplied. This can, for example, be implemented with a viewing window in the removable cassette and an optical monitoring system in the device.

[0029] This can prevent a falsified infusion pressure reading, a reduction in dynamic response during a change in infusion pressure due to elastic air bubbles in the infusion system, and / or the infusion of air into the eye. Furthermore, when filling the tubing system, it can detect when the water column reaches the cassette, which can, for example, shorten the filling cycle. This sensor can also detect when only air is coming out of the infusion bottle instead of BSS. An error message can then warn the operating room staff and prompt them to connect a new BSS bottle before the eye collapses.

[0030] The infusion delivery device can be configured with at least one, at least approximately circularly arcuate squeeze channel made of an elastic material in the interchangeable cassette, the squeeze channel cross-section of which can be sealingly squeezed at at least one point by actuators on the device using rollers, and this point can be movable along the squeeze channel (94). In particular, a squeeze channel cross-sectional area can be configured to vary along the uncrushed squeeze channel. Specifically, multiple squeeze channels can optionally be hydraulically arranged in parallel and controlled out of phase by a single infusion delivery device to avoid ripple effects of the peristaltic pump.

[0031] An interchangeable cassette according to the invention for an ophthalmological device can thus be designed with at least one rigid hard part as the housing of the interchangeable cassette and at least one elastic soft part. The hard part can be made in particular from a hard plastic, specifically a thermoplastic such as polypropylene (PP) or polyethylene (PE). The soft part can be made in particular from an elastomer or a thermoplastic elastomer. At least one of the hard parts can be designed with at least one soft part as a one-piece, multi-component injection-molded part. The hard part and the soft part form internal fluid channels of the interchangeable cassette, with the soft part being at least partially accessible from the outside. In this case, regions of the soft part are also specifically designed as cassette-side peristaltic pump squeeze channels for conveying infusion fluid in at least one of the fluid channels.

[0032] The soft tissue can form a variety of functional elements of the interchangeable cassette. For example, at least one of: a squeeze pump region for air or liquid in the liquid channels for volume delivery in the form of a peristaltic pump, a valve device region for changing a flow cross-section in at least one of the liquid channels, a pressure sensor region for determining an air or liquid pressure in at least one of the liquid channels, and / or a ripple compensation region for compensating pressure and / or volume fluctuations in a liquid delivery by means of an elastic liquid channel region.

[0033] The removable cassette can also be equipped with at least: a bottle connection for connecting a container for providing infusion fluid, an infusion connection for supplying the infusion fluid to the ophthalmic surgical instrument, an aspiration connection (50) for connecting at least one of the fluid channels to an ophthalmic surgical instrument, and a waste connection (55) for discharging fluid into a waste container (56), and / or an aspiration valve.

[0034] The invention also relates to a method for automatic infusion pressure control in an ophthalmic device, which can be performed specifically during suction irrigation. This involves an active and specifically motor-controlled aspiration volume delivery of an aspiration fluid from an aspiration port to a waste container, and an active and specifically motor-controlled infusion volume delivery of an infusion fluid from an infusion container to an infusion port. The infusion volume delivery and the aspiration volume delivery are each performed by means of a peristaltic pump. Instead of the infusion fluid, for special applications in vitrectomy, the infusion delivery device according to the invention can also be used to deliver air instead of liquid—that is, to provide a controlled infusion of air or another gas. This is described in detail below.

[0035] This can involve measuring the infusion pressure of the infusion fluid (or alternatively, in special cases, the infusion air) and regulating the delivery volume of the infusion volume delivery based on the infusion pressure. Specifically, this control can take place taking into account a pressure drop in a line leading to the eye, which is at least partially compensated by an increase in pressure during the infusion volume delivery, so that the desired pressure in the eye actually prevails. According to the invention, this pressure drop can be determined, in particular, taking into account the flow rate of the infusion fluid, since the flow rate can be determined based on the current delivery volume of the infusion volume delivery.

[0036] According to the invention, the delivery volume of the active infusion can also be adjusted to a characteristic value of the active aspiration. Specifically, a dependency of the movement of an infusion peristaltic pump on the movement of an aspiration peristaltic pump can be implemented. In particular, a negative aspiration pressure can be determined during the aspiration volume delivery, and if the negative aspiration pressure increases, the infusion pressure can be temporarily increased, for example, in the case of aspiration occlusions. This temporary increase in the infusion pressure can counteract an undesirable pressure reduction in the eye during the release of the aspiration occlusion.

[0037] According to the invention, a method for controlling an active infusion in an ophthalmic device for suction irrigation is carried out by a control unit, with the control unit determining an aspiration flow rate of an aspiration of the suction irrigation and pre-controlling an infusion flow rate of the active infusion to compensate for the aspiration flow rate. In addition, an infusion pressure of the active infusion is determined and the pre-controlled infusion flow rate is adjusted to achieve a desired infusion pressure.

[0038] Some methods described here are preferably provided at least partially as programmed sequences. The invention therefore also relates to computer program products with program code stored on a machine-readable medium or provided as a computer data signal embodied by an electromagnetic wave (e.g., as a radio signal) for carrying out the above method. The program code can specifically execute, or be configured to execute, the control and / or regulation tasks mentioned here, as well as process sequences in an ophthalmological device automatically.

[0039] The method and device according to the invention are described in more detail below using specific embodiments schematically illustrated in the drawings, purely by way of example, and further advantages of the invention are also discussed. In detail: Fig. 1 a first block diagram of a first embodiment of an ophthalmological device according to the invention; Fig. 2 a second block diagram of a second embodiment of an ophthalmological device according to the invention; Fig. 3a und Fig. 3b a first embodiment of an example of an interchangeable part according to the invention in the form of an exchangeable cassette for an ophthalmological device in 3D views from the left and right; Fig. 4 a representation of an exemplary embodiment of an interchangeable part according to the invention, which is inserted into a corresponding example of an ophthalmological device according to the invention; Fig. 5 a plan view of an embodiment of an infusion fluid conveyor according to the invention; Fig. 6a und Fig. 6b Embodiments of examples of an interchangeable part according to the invention when inserted into the device in a sectional view; Fig. 7a und Fig. 7b Embodiments of an example of an interchangeable part according to the invention with an embodiment of an optional ripple reduction; Fig. 8a und Fig. 8b a representation of an exemplary embodiment of an interchangeable part according to the invention with an active infusion conveying device according to the invention; Fig. 9 a first example of an embodiment of an active infusion according to the invention in use; Fig. 10 a second example of an embodiment of an active infusion according to the invention in use.

[0040] The representations in the figures are for illustrative purposes only and, unless explicitly stated, are not to be considered to scale. Identical or functionally similar features are, where practical, provided with the same reference numerals throughout and, where appropriate, differentiated by a letter as an index. The diagrams shown each show the basic technical structure, which can be supplemented or modified by a person skilled in the art according to general principles.

[0041] Fig. 1 shows a possible example of a block diagram of an embodiment of an ophthalmic cassette 1 according to the invention with at least one active infusion device according to the invention. In this example, it can specifically be an infusion device in an exchangeable cassette 1 of an ophthalmic device 99, with which a suction rinse can be performed. The left half of the figure shows an active infusion device, and the right half shows an aspiration device.

[0042] A container 30, for example an infusion bottle or an infusion bag, provides an infusion fluid, e.g. a BSS (balanced salt solution) or another infusion fluid. This infusion fluid supply can be equipped, for example, with a device for monitoring the fill level. For this purpose, the container 30, a drip chamber 31, a connecting tube and / or a cassette-internal fluid channel can be monitored for emptying with a wired or wireless sensor. The connection 33 can be arranged on the cassette 1 - accessible from the outside when the cassette 1 is inserted - and can be connected, for example, via a tube to the infusion container 30 or to the drip chamber located therebetween.

[0043] As is known in the prior art, the infusion fluid pressure at the bottle connection 33 of the cassette 1 (or in the entire infusion system) can optionally be changed by varying the height of the container suspension, preferably by a motorized and automatic height adjustment of the container 30 suspension, symbolized here by the drive 32. However, with the active infusion system according to the invention, this height adjustment is not absolutely necessary, but can be implemented as a switchable option and / or as additional safety or redundancy on the device according to the invention.

[0044] In another embodiment of a cassette 1 according to the invention, an active infusion can be carried out exclusively by means of an active fluid delivery device 36. For this purpose, a pumping device, such as a peristaltic pump or another fluid delivery device, is configured in the infusion system. In such an embodiment, an infusion valve 35 and / or a height adjustment of the infusion container 30 can optionally be omitted. By appropriately controlling the delivery device 36, the infusion pressure and / or the delivery volume of the infusion can be varied, in particular controlled or regulated.

[0045] A further preferred embodiment of a cassette 1 according to the invention can also - as shown in the figure - have both an infusion container height adjustment 32 and an infusion fluid conveying device 36. In such an embodiment, the cassette 1 according to the invention can additionally be provided with a setting or regulation of the infusion pressure as described here by changing the height difference between the container 30 and the infusion site. In particular, a valve 35 can be designed as a bypass to the conveying device 36. Thus, with the same cassette 1, either an active (i.e. actively initiated by the conveying device 36) or a hydrostatic (i.e. caused by a height difference) infusion pressure variation can be provided. In particular, a seamless transition can be made between these two principles, if required - for exampleThe pressure can be switched between the two pressures simultaneously, even during operation, for example, according to the current requirements of the operation being performed or the surgeon's preferences. Special applications requiring two different and independent infusion pressures simultaneously can also be implemented with such an embodiment of the invention, by applying a first pressure-regulated infusion to the eye via a first line using the hydrostatic height adjustment, and a second pressure-regulated infusion with the active infusion using the infusion delivery device in the cassette via a second line to the eye.

[0046] The infusion system according to the invention also has an infusion pressure measuring device 37, by means of which a pressure in the infusion system can be determined, monitored, and / or regulated. This infusion pressure measuring device 37 is preferably arranged downstream of the infusion valve 35 and / or the pump device 36, so that the pressure determined corresponds to the pressure supplied to the eye. Since only overpressure can (or at least should) prevail in the infusion system compared to the atmosphere, this infusion pressure measuring device 37 can be designed such that it can only determine overpressure, and not necessarily also underpressure (although such a variant would also be applicable). One of many possible examples of a specific embodiment can be formed, for example, with a part of the infusion fluid channel expanded to form a pressure chamber, which has a flexible membrane on the outside.When cassette 1 is inserted, this membrane rests against a sensitivity surface of a force or pressure sensor in device 99. The force exerted on the membrane by an overpressure in the fluid channel relative to the atmosphere can thus be determined as a measured value for the overpressure in the fluid channel.

[0047] The infusion fluid is provided by means of the cassette 1 according to the invention with active infusion according to the invention with adjustable pressure and / or flow volume at an external infusion connection 38 of the cassette 1, which can be connected to a line or tube leading to the surgical interventional tool, e.g. the surgical handpiece 29, so that the infusion into the eye can be provided with adjustable and / or controllable pressure and / or volume. To ensure safety, the actual prevailing pressure of the infusion to the patient can be monitored with a corresponding pressure sensor 37. If necessary, pressure losses in the line system to the patient can also be taken into account - especially dynamic pressure losses, since according to the invention the flow volume and thus also the flow rate of the infusion are known via the delivery device 36.

[0048] Preferably, according to one aspect of the invention, the arrangement and design of the fluid channels within the cassette 1 is such that when the fluid channels are filled with fluid, this filling always occurs (at least substantially) from bottom to top - whereby any air bubbles (corresponding to the medium density ratio) are displaced upwards and carried away from the patient, and an accumulation of air bubbles is avoided. Such filling of the fluid channels of the cassette 1 occurs in particular after the cassette 1 is inserted during its commissioning. In this case, for example, according to this aspect of the invention, the arrangement of the connections can be designed from bottom to top in the following order: waste bag 55 - aspiration A from the patient 12a, 50 - possibly aspiration B 12b - infusion to the patient 38 - infusion bottle 33.

[0049] The cassette 1 according to the invention can have at least one air bubble sensor 34 in the infusion system, with which correct function can be monitored and the infusion of air can be prevented. The air bubble detector 34 can operate in particular optically—for example, based on different light refraction properties of air and liquid—or also on other principles with which a distinction can be made between the presence of gas or liquid in the infusion system. For example, the principle of different angles of total reflection of liquid compared to air, different light conduction properties of liquid and air, or another operating principle, such as a capacitive one, can be used.An example of a specific embodiment can be formed with a viewing window in the fluid channel that is optically transparent at least at the wavelength used, which can be implemented in an outer shell 41, 42 of the cassette 1. In one embodiment, the outer shell can be made of transparent material, for example.

[0050] Also shown here is an optional path according to the invention from the infusion system to the aspiration system of the cassette 1, which can be opened using a venting valve 39. This can be used, for example, particularly when the cassette 1 is put into operation, to fill the aspiration system with fluid and / or to backflush infusion fluid through the aspiration system, for example to release occlusions (reflux) or generally to reduce negative pressure in the aspiration path, e.g., if the physician wishes to reduce the desired negative pressure via a foot switch. For these functions, additional valves may be present in the cassette to switch the fluid flows accordingly.

[0051] The aspiration system of the cassette 1 according to the invention is connected to a line or hose via an aspiration connection 50, also leading to the surgical intervention tool 29. Here, too, at least one air bubble sensor 34b can be present in the aspiration system. An aspiration valve 51 is also shown in the figure. Pressure measurement can also be performed in the aspiration system using a pressure measuring device 10, which can, however, detect both negative and positive pressures relative to the atmosphere. In order to be able to detect forces in both positive and negative directions, the pressure measuring membrane of the cassette must be connected to the associated pressure measuring sensor in the device for transmitting both positive and negative values.Examples of such known pressure detection devices can be found in patent application EP 16197018, filed on the same day by the same applicant, which is hereby incorporated by reference, or possibly also in the references cited therein.

[0052] To achieve the aspiration effect, the figure shows two variants: one is peristaltic aspiration and the other is Venturi aspiration. One embodiment of a cassette 1 according to the invention can either feature only peristaltic aspiration, another embodiment of a cassette 1 according to the invention can feature only Venturi aspiration, or another embodiment of the invention can feature both peristaltic aspiration and Venturi aspiration.

[0053] In Venturi aspiration, the aspiration effect is achieved by negative air pressure, which is usually generated with a Venturi nozzle or a vacuum pump. These variants are symbolized here by the Venturi valve 57 and the negative pressure system 58. Specifically, a so-called "Clean Venturi" system can also be used, which is described in international application EP 16196998, filed on the same day by the same applicant and is hereby incorporated by reference. In Venturi aspiration, a measured value of the aspiration negative pressure can, in particular, be used as the basis for controlling the active infusion delivery device 36, e.g., as described further below. Specifically, the active infusion delivery device 36 according to the invention can be controlled and / or regulated based on the currently prevailing infusion pressure and the currently prevailing aspiration negative pressure by a control unit provided for this purpose.Optionally or alternatively, the control unit can also include values ​​of the current flow rate of the infusion and / or aspiration.

[0054] During peristaltic aspiration, a fluid conveying device 52 is used to generate the aspiration effect. The conveying device 52 can, in particular, be a peristaltic pump, but optionally, a diaphragm pump or other fluid conveying device can also be used. The aspirated fluid is preferably conveyed into a corresponding waste container 56, which is preferably connected to a corresponding waste port 55 outside the cassette 1. A pressure sensor 37c, in particular for overpressure, can be used to detect a pressure increase when the waste bag is full.

[0055] The cassette 1 according to the invention can also have a coding 70, in particular a mechanical and / or optical one, which can be detected and evaluated by a corresponding reading unit 71 of the device 99. This coding can be used to prevent multiple or non-sterile use—for example, in the case of disposable cassettes—and to recognize a specific embodiment of the inserted cassette and its optional functionalities, etc., by the device 99.

[0056] In special vitrectomy procedures, when the vitreous body is removed, a gas, usually ambient air from the operating room purified with a bacterial filter, is first pumped into the eye, usually at an overpressure of approximately 20 to 120 mmHg. This pumped-in air is then replaced with silicone oil, which presses the detached retina back against the choroid, allowing it to reattach. In the prior art, a specially designed air pump is required in the device for this purpose, but this is rarely actually used. If a peristaltic pump is specifically used as the active delivery device 36 for the infusion according to the invention, this can also be used to deliver gases instead of infusion fluid.This not only results in a simpler device design by eliminating the need for a special air pump, but also offers significant advantages in terms of hygiene and sterility, as the interchangeable cassette 1 is sterilized and regularly replaced. As an optional accessory, a preferably sterile and / or disposable bacterial filter can be attached to the bottle connection of the interchangeable cassette 1, which filters the infusion air drawn in.

[0057] Fig. 2 shows a further exemplary embodiment of a cassette 1 according to the invention in a block diagram. Fig. 1 Functionally identical or equivalent features are provided with the same reference symbols and reference is made to their description above.

[0058] The essential differences between this embodiment of the invention and Fig. 1 According to the invention, only active infusion takes place in the infusion area by means of a delivery device 36. The infusion valve 35 is only optionally designed here as an additional barrier against the patient - but can also be omitted, particularly if the fluid delivery device 36 already has a sealing effect. A passive or active ripple compensation element 59 for a peristaltic pump 36 is also shown in the infusion path. Passive compensation can, for example, be designed with a flexible region of the fluid channel which has the effect of a compensating bellows, which cushions pressure or delivery rate ripple by deforming according to the ripple. Alternatively or additionally, active ripple compensation can also be used, in which an actuator on the device deforms a flexible region of an infusion fluid channel and in the process compensates for pressure or delivery rate ripple effects.The actuator can be controlled, for example, based on values ​​from pressure sensor 37 and / or based on information about the rotational position of peristaltic pump 36. According to the invention, the rotational speed of the peristaltic pump can also be dynamically varied in such a way that the ripple effect of the conveying device is minimized. In contrast to a conventional, uniform rotary movement (with at most an accelerated or decelerated phase when the delivery rate changes), as used in the prior art, there is no strictly uniform rotary movement of the roller head during conveying; instead, the rotational speed is modulated with the period of the roller engagement in such a way that the delivery rate ripple occurring with this period is compensated as much as possible.There is therefore a temporary acceleration or deceleration of the roller head movement when a roller enters the area of ​​the inlet or outlet of the squeeze channel (inlet or outlet, depending on which side the ripple is to be compensated, i.e. during supply or extraction).

[0059] In the aspiration area, according to the invention, the waste bag 56 can be attached directly to the cassette 1. In addition to the aspiration port 50a, a second, optional aspiration port 50b with corresponding aspiration valves 51b and 50b is also shown for selection. The optional pressure sensor 10b can additionally monitor the pressure in the suction chamber of a Venturi system.

[0060] According to the invention, the infusion pressure can also be adjusted significantly more quickly than is possible with the prior art. This can be achieved, in particular, depending on the surgical step or specific circumstances that arise during the operation.

[0061] With the data known according to the invention regarding the flow rate of the active infusion and the aspiration, the tightness of the incisions (=opening in the eye) can also be determined and this information can be made available for display or further processing.

[0062] The embodiments of an active infusion system according to the invention described here offer a number of advantages over known infusion systems, such as gravity infusion or infusion by pumping air into the infusion area. Specifically, an active infusion system according to the invention, particularly with a peristaltic pump, offers advantages such as:Simplification of surgical setup and device commissioning – thus saving time, especially since initial filling of the infusion system is significantly easier and faster. Reduced risks of sterility errors, especially during device setup. Faster pressure changes during the procedure than with the state of the art can be performed, opening up many previously unknown application possibilities. Independence from a specific infusion fluid supply, particularly regarding bottle size and type, as this has no impact on the active infusion according to the invention. Additional monitoring functionalities, parameter evaluations, safety and comfort features, etc., can be implemented. Less waste is generated, as air filters, long needles for the infusion set, tubing, packaging, etc., can be eliminated.Only the interchangeable cassette required for aspiration is required – which can optionally be designed to be sterilized multiple times. Consumable costs are also reduced.

[0063] In Fig. 3a und Fig. 3b A further embodiment of a cassette 1 according to the invention is shown, each viewed from the front right and left. The functional elements previously described in the block diagram are also shown and labeled in the figures. In this example, the cassette 1 is shown as a base cassette 1a whose outer contours are at least approximately cuboidal, with a projecting plate as the front section 1b. Connections for hose systems can be found on the front section 1b, in particular those for the surgical handpiece, for the infusion fluid reservoir 30, and for a waste bag 56. These connections 33, 38, 50, 55 are preferably mechanically and / or geometrically coded, as shown, to prevent the risk of incorrect connection and confusion.

[0064] In the illustrated example of an embodiment, the functional elements of the cassette 1 are each divided between both of the outer shell halves 41 and 42 of the cassette 1, thus achieving a compact structure. Specifically, the squeeze pump sections 36 and 52 are arranged on one cassette side 42, and the valves and pressure sensors are arranged on the opposite cassette side 41. Such a division of the functional elements is not mandatory, but can be advantageous with regard to clamping or securing the cassette 1 in the device 99, in which the pressing of the roller head(s) of the peristaltic pump can simultaneously clamp, fix, and / or finely position the cassette 1 in the device 99. The movement required to clamp the cassette in the device 99 can occur from only one side, preferably from the side of the peristaltic rollers.The following figures illustrate in detail a further exemplary embodiment of a peristaltic pump according to the invention of a cassette 1 according to the invention.

[0065] Fig. 4 shows an exemplary embodiment of a cassette 1 according to the invention in its final position in a cassette slot of a device 99. Insertion is achieved by pushing the cassette 1 into the cassette slot in the insertion direction 91 and can be manual or at least partially automated or motorized. A portion of the cassette slot is shown in section, but the cassette 1 is uncut. In the position shown of the cassette 1 in the device 99, rollers can be pressed onto the squeeze areas of the peristaltic pumps 36 and / or 52 essentially orthogonal to the side of the cassette 1 shown in the direction 27, whereby the cassette 1 can be simultaneously positioned and fixed in the device 99 according to the invention. In this inserted state, the device-side sensors and actuators are in a position with respect to the cassette in which they can interact specifically with their respective associated functional elements of the cassette 1.

[0066] Fig. 5 shows schematically such a clamping and fixing of the inserted cassette 1 in the device 99 in a side view, looking towards the peristaltic pumps of the cassette 1 (direction 27 in Fig. 4 ). A device-side roller head 72 with rollers 73 is shown, which rollers 73 roll on the bead-shaped, curved squeeze area 94 of the outer shell 42, which is made of elastic, soft plastic 44. During this rolling, the squeeze area 94 is pressed by the rollers 73 in a sealing manner onto the core part 43 of the cassette 1, and upon rotation of the roller head 72 about the rotation center 75, a volume is conveyed in the squeeze area 94 between the rollers 73. For rotating the roller heads 72, the device 99 has an infusion drive 76 for the infusion conveying device 36 and an aspiration drive 77 for the aspiration conveying device 52.

[0067] In Fig. 6a The cassette 1 is inserted into the device 99 in the insertion direction 91, which in this figure runs orthogonally to the plane of the drawing, up to its end position, but not yet clamped. This is a sectional view through the right and left rotation centers 75a and 75b of the two separate peristaltic pumps 36 and 52 from Fig. 5 In the example shown, the cassette 1 shown in section is essentially constructed in three parts, with a left outer shell 41, a right outer shell 42 and a core part 43. The outer shells 41 and 42 are preferably designed so that they can be snapped, pressed or squeezed against one another and / or against the core part 43, for example with a hook system, a press-fit system or the like, which in particular can be designed so that they cannot be removed again. The outer shells 41 and 42 can in particular be designed as 2-component injection-molded parts made of a rigid hard plastic part and an elastic soft plastic part. The elastic soft plastic part is then clamped and squeezed and / or positively engaged with the core part 43, so that the fluid channels or lines within the cassette 1 are formed and sealed.In the section shown, the elastic portion 44 forms bulges along the fluid channels, which, when assembled, engage in the recess of the core portion 43—thus creating a fluid seal, particularly by squeezing the soft plastic 44 and / or forming a meander seal with at least one step. Partial areas of the soft plastic portion 44 are accessible from the outside when the cassette 1 is assembled and form the functional elements. The hard plastic portion of the 2K injection-molded outer shells 41 and 42 has corresponding cutouts for this purpose, which provide access to the soft plastic 44. The possible sterilizability of the entire cassette, for example, in an autoclave, etc., can also be taken into account when selecting the cassette material if a reusable design is desired.

[0068] In this example of an embodiment of the invention, after insertion, the cassette 1 is clamped together with the roller heads 72 of the peristaltic pump being pressed in direction 83. As shown, the clamping force of the rollers 73 and / or the position alignment 82 can be determined by means of springs.

[0069] Also arranged in accordance with the invention in the device 99 are the actuators (not visible here), which act on the valves 35, 39, 51, 51a, 51b and / or 57 and can be designed, for example, as electromagnetically or electromotively or pneumatically actuated tappets in the device, which mechanically act on the valve formations of the cassette 1. The pressure detection device 10, specifically its coupling element, is also coupled to the device-side force sensor 11 (not shown here) when the cassette 1 is inserted. In the same way, the cassette-side membrane of the pressure sensor 37 and / or 37c is brought into a functionally operative connection with a device-side force or pressure sensor.

[0070] Fig. 6b shows the cassette 1 in the clamped state in the device 99, in which all sensors and actuators of the device 99 correspond with their counterparts in the cassette 1 for interaction. In the example shown, this occurs by clamping the cassette 1 in the device 99, which is achieved by pressing the roller heads 72 against the cassette in the direction 83. The cassette 1 is thus pressed to the left in the plane of the drawing onto corresponding mechanical stops. The rollers 73 squeeze the squeeze channels 94 - whereby in the case of the upper pump (e.g. the infusion pump 36) a section through the roller 73 with a squeezed squeeze cross-section 94 and in the case of the lower pump (e.g. the aspiration pump 52) a section next to a roller 73 and correspondingly an uncrushed squeeze cross-section 94. With the centering elements 82, which in this example also form the rotation axis 75 of the roller head 72, a fine positioning of the cassette 1 in the device 99 is also effected when the cassette 1 is clamped.

[0071] Fig. 7a shows an exemplary embodiment of a cassette 1 according to the invention in which a cassette-side pumping device 36 for the active infusion according to the invention and a further pumping device 52 are shown.

[0072] Shown are a first pumping device 36 according to the invention for infusion and a separate, second pumping device 52 for aspiration. These pumping devices are formed with the soft regions 44 of the outer shell 42, which form outwardly curved pinch channels 94. Through the engagement of rollers 73, these pinch channels 94 are pressed onto the core part 43 in a locally sealing manner. By moving the rollers 73 along the pinch channels 94, a volume can be pumped into the pinch channels 94. This movement can be effected here by rotating a roller head 72 about the rotation axis 75b, with the roller head 72 carrying the rollers 73a and 73b. Specifically shown are some of the device-side rollers 73c and 73d, which move on concentric circular paths and engage in the respectively associated cassette-side squeeze channels 94c and 94d, respectively, and cooperate with these to form the pumping device 52.The same applies to the pumping device 36, although for the sake of clarity the rollers assigned to the squeeze channels 94a and 94b are not shown here.

[0073] One aspect of the invention for reducing ripple effects, shown in this specially developed embodiment, lies in the dual pump design with at least two adjacent squeeze regions 94c and 94d. These are designed and arranged in such a way that the ripple in the two adjacent squeeze channels 94c and 94d caused by the squeeze pumping effect balances each other out as much as possible, thus reducing the overall ripple of the pump. This can be achieved, for example, by offset squeeze rollers 73c and 73d, as shown, which cause a phase shift of the pressure or flow rate ripple generated by the two squeeze channels 94c and 94d. The two inlets and the two outlets of the squeeze channels 94c and 94d are each hydraulically connected to one another. In particular, a phase shift of the ripple curves by approximately 180 degrees for two channels can bring about an advantageous reduction.With a different number of pinch channels 94, the phase shift must be selected accordingly. Alternatively or additionally, the position and / or shape of the inlets and / or outlets of the two pinch regions 94 can also be designed differently to achieve the aforementioned phase shift and / or a further ripple reduction. Thus, with such a further developed embodiment and appropriate design, a ripple reduction can be achieved compared to a single pinch region.

[0074] In the at least approximately concentric arrangement of two interconnected squeeze channels 94c and 94d shown here, it can also be taken into account that different curve lengths also occur with their different curve radii. To compensate for ripple, according to the invention the liquid channel cross-sectional dimensions, cross-sectional shapes and / or cross-sectional profiles of the outer curve 94c can be designed differently from the inner curve 94d in such a way that the volume conveyed per unit of movement of the rollers 73 always remains at least approximately the same - or the volumes always balance each other out as much as possible and, in total, result in the smallest possible ripple of the total volume conveyed. For example, in such a way that over one entire revolution of the roller head carrying the rollers 73, the outer and inner squeeze tracks 94c and 94d each convey orhave a flow volume ripple that is as even as possible. Different squeeze radii caused by possibly different diameters of the engaging rollers 73c and 73d can also be taken into account in these considerations.

[0075] Fig. 7b shows the embodiment of Fig. 7a again in a sectional view through the cassette 1. The fluid channels in the area of ​​the peristaltic pump are formed inside the cassette 1 by the hard plastic core part 43, over which an elastomer part 44a of the outer shell 42, curved towards the outside of the cassette 1, forms a partial area of ​​the fluid channel. This partial area, which is also referred to as the squeeze area 94 of the pump, can be squeezed by engaging, device-side rollers 73 in the manner of a peristaltic pump, whereby the fluid or air located in the fluid channel can be conveyed when the rollers 73 move. In particular, according to the invention, the cross-sectional area of ​​the squeeze area 94 formed in this way can vary over its length.As shown in this example of an embodiment according to the invention, a tapering of the cross-section toward the pump outlet and / or an enlargement or reduction of the (unsqueezed) cross-section at the pump inlet can be achieved. In particular, by optimizing this cross-sectional change, pressure and / or flow rate fluctuations (also referred to as ripple) during pumping can be minimized. An advantageous cross-sectional profile along the squeezing area 94 can also be determined, for example, by means of simulation and / or test series.

[0076] Fig. 8a shows the cassette 1 with exemplary roller heads 72 engaged. For the sake of clarity, only the lower rotatable roller head 72b, to which the rollers 73b are attached, is indicated in the figure - in the upper pump device, only the rollers 73a are shown, but not the associated roller head 72a. In the example shown here, a first roller head 72a and a second roller head 72b of the respective separate pumps for infusion and aspiration engage on the same side of the cassette 1. In another embodiment, the first and second roller heads 72a and 72b can also engage on opposite sides of the cassette 1. In particular, but not necessarily, the axes of rotation of the roller heads can be arranged opposite one another and form at least an approximately common axis of rotation, which can bring advantages with regard to the distribution of force on the cassette 1.

[0077] In this embodiment according to the invention, the squeezing areas are each only single, i.e. without a hydraulically parallel second squeezing channel as in the previous embodiment of Fig. 7a und 7b executed.

[0078] In the example of the embodiment according to the invention shown here, the two pumps 36 and 52 each describe at least approximately a semicircle on the cassette 1. This results in advantageous use of the space available on the cassette 1 shown as an example, especially with ease of handling and manufacture. A concentric arrangement of the two pumps 36 and 52 would also be possible, but would be comparatively more complex in terms of construction. Alternatively, the bead-shaped, curved squeeze area 94 of the pump 36 and / or 52 can, in another embodiment, also be designed with a different, in particular smaller, arc length, although a corresponding arrangement and number of rollers 73a and 73b must always be selected so that sufficient pumping behavior can be ensured - i.e., in particular, at least one, preferably more than one, roller 73a is always engaged in each squeeze area 94.

[0079] As in Fig. 8b As illustrated in Figure 1, this can be achieved according to the invention, for example, by arranging the roller axes 74 obliquely relative to their rolling planes on the squeeze channels 94, and preferably intersecting with this rolling plane at the rotation center 75 of the roller head 72 carrying the rollers 73. The frustoconical rollers 73 thus roll optimally on the soft plastic area 44b of the outer shell 42 forming the squeeze channels 94, and squeeze this against the core part 43. Alternatively, however, other geometries can also be used. The shaping and arrangement is preferably such that the circumference of the roller 73a or 73b at a particular point is proportional to the circumference of the circular path described by the roller at that point around the pivot point 75a of the center of the roller head 72a.

[0080] Fig. 9 shows an exemplary embodiment of an example of an inventive, interdependent control of the infusion conveying device and aspiration conveying device according to the invention. The "normal state" is shown at the beginning, in which the infusion pressure P-inf is at least approximately constant and the aspiration volume V-asp is also at least approximately constant - for example, an aspiration peristaltic pump rotates at an average constant speed. An occlusion of the aspiration tool is shown as a bar on the abscissa, which represents a time axis. For example, when a shattered lens particle blocks the suction needle tip, the aspiration negative pressure in the device increases, as shown by the corresponding curve. According to the specific partial aspect of the invention described here, in such a case, the rapid, dynamic control orThe infusion pressure can be regulated with the infusion delivery device according to the invention; starting at a certain aspiration negative pressure, the infusion pressure can be increased as a precaution, as shown by the corresponding curve. This can be done automatically by a control unit in the device 99, i.e., without any intervention by the physician. This occurs in preparation for the expected break in the occlusion, i.e., when the occlusion dissolves and the suction needle is released again - i.e., at the end of the occlusion bar shown. Then, due to the increased aspiration negative pressure, there is a brief increase in the amount of fluid aspirated - which could lead to (at least slight) collapse of the eye. However, this can be largely compensated for by the inventive partial aspect of the precautionary, temporary increase in infusion pressure, since during the (e.g.,In the event of an occlusion (as evidenced by the increase in aspiration pressure), more infusion fluid has already been pumped as a precautionary measure. This ensures that sufficient fluid is available in the eye when the occlusion is released, preventing or at least reducing collapse (collapse of the anterior chamber). After the occlusion is released and the negative aspiration pressure has returned to normal, the infusion pressure can also be normalized.

[0081] Fig. 10shows an exemplary embodiment of an example of a dynamic adjustment of the infusion pressure with the active infusion according to the invention as a partial aspect of the invention. Shown is a diagram in which, by way of example and simplified to the basic principle, the delivery volume F-asp of the aspiration delivery device and the delivery volume F-inf of the active infusion delivery device controlled according to the invention as a function of this are shown. This dependency is represented here by way of example in such a way that the infusion is controlled as a function of a predetermined aspiration - however, embodiments can also be implemented in the sense of the invention in which the desired infusion is predetermined and the aspiration is controlled as a function of this. In the diagram, the infusion volume is always somewhat larger than the aspiration volume, since leakage losses are compensated for when opening the eye.Preferably, the shown dependence of infusion and aspiration is used as a type of feedforward control, to which a control of the actually prevailing infusion pressure can be superimposed. The control is thus simplified and can be designed more dynamically, since the control deviation to be compensated is only small. In addition, with a significantly longer time constant, the feedforward control can also be slowly adjusted according to the actually occurring leakage loss, if necessary, and adapted to the losses actually occurring during the specific operation. For example, at the beginning of the procedure, the feedforward control can be carried out with a leak rate compensation of, for example, 7%, which is customary for this procedure. This percentage can then be used, for example,is adjusted to 5% if the superimposed control causes a continuous reduction in the infusion volume over a longer period of time - i.e. the intervention opening is tighter than usually assumed.

[0082] The upper part of the diagram also shows the infusion pressure P-sens at the pressure sensor in the cassette, which corresponds to the infusion flow rate F-inf and is adjusted according to the invention. The increase in the infusion pressure P-sens in the cassette, which according to this aspect of the invention is dependent on an increase in the flow rate F-inf, compensates for, in particular, an increased pressure drop in the line to the patient caused by the flow rate and results in a more balanced, constant infusion pressure P-inf in the eye than in the prior art. Parameters for this flow-rate-dependent target infusion pressure adjustment, for example the curve of the P-sens adjustment, can be determined, stored, and made available, for example, experimentally or mathematically, for a particular tubing set in use.

[0083] In the current state of the art, without active infusion, the above-mentioned advantageous developments cannot even be considered, as they cannot be implemented with the sluggishly reacting systems of the current state of the art. Furthermore, the problems that these advantageous developments solve are neither known nor of obvious relevance in the current state of the art.

[0084] Another problem with the current technology is that relatively thin tubes are often used for infusion, and therefore the pressure drop between the BSS bottle and the device cannot be ignored, especially with high infusion flow rates. It also frequently occurs that a negative pressure develops in the BSS bottle, which, in the current technology, has a negative impact on the infusion pressure. For example, a filter in the drip chamber, which causes too much pressure drop, also has a negative effect. With gravity infusion, in these cases, the pressure in the eye is simply reduced, resulting in less stability.

[0085] With the active infusion according to the invention, none of this is a problem, as the above-mentioned problems have no, or at least hardly any, impact on the infusion pressure in the eye, or are actively compensated for by the active infusion. In particular, pressure measurement on the patient side of the fluid delivery device, together with pressure regulation via a peristaltic pump, can compensate for the aforementioned pressure losses. Furthermore, the peristaltic pump can also act as a suction force from the direction of the BSS bottle, which allows the flow rate to be compensated even in the event of a high pressure drop in the line, drip chamber, infusion bottle, etc. According to the invention, higher flow rates from the BSS bottle can therefore be achieved - if necessary - than with gravity infusion alone, which can be very helpful in some surgical situations. In particular, it allows for quick and dynamic responses to any changes, making the operation safer.In particular, according to the invention, such a rapid and dynamic response to any malfunctions can also be implemented automatically by the device, i.e., without or with minimal intervention by personnel. Specifically, this can be achieved via a controller module for controlling the infusion fluid delivery system, which automatically maintains or follows predefined setpoints and / or setpoint profiles of the infusion pressure based on the sensors of the interchangeable cassette.

Claims

1. Ophthalmological device (99) which provides suction flushing with an aspiration function and an infusion function, comprising • an aspiration conveyor device (52) for the motor-driven discharge of liquid from a surgical instrument (29) into a waste container (56), in particular in the form of a peristaltic pump or a Venturi aspiration with vacuum suction, • an infusion conveyor device (36) for the motor-driven feeding of an infusion medium from an infusion container (30) via an infusion connection (38) and a line to the surgical instrument (29), characterized in that the infusion conveyor device (36) is designed as a peristaltic pump for the active volume delivery of the infusion medium with a known delivery volume, and a pressure measuring device (37) with a pressure or force sensor in the device is formed between the infusion conveyor device (36) and the surgical instrument (29), by means of which an infusion pressure of the infusion medium in the device can be determined.

2. Ophthalmological device (99) according to claim 1, characterized in that a control module in the device (99) is designed such that the delivery volume of the infusion volume delivery is regulated on the basis of the infusion pressure.

3. Ophthalmological device (99) according to claim 2, characterized in that the control module in the device (99) is designed such that the regulation is carried out under consideration of a pressure drop in the line towards the surgical instrument (29), wherein the pressure drop is at least partially compensated with a pressure increase in the infusion volume delivery.

4. Ophthalmological device (99) according to claim 3, characterized in that the control module in the device (99) is designed such that the pressure drop is determined by taking into account a flow velocity of the infusion medium, which flow velocity is determined on the basis of the current delivery volume of the infusion volume delivery.

5. Ophthalmological device (99) according to one of claims 1 to 4, characterized in that regions of the infusion conveyor device (36) that come into contact with the infusion medium together with regions of the aspiration conveyor device (52) that come into contact with the liquid are formed in a common interchangeable cassette (1) for the device (99), and the device (99) comprises an infusion drive (76) for the infusion conveyor device (36) and an aspiration drive (77) separate therefrom for the aspiration conveyor device (52).

6. Ophthalmological device (99) according to one of claims 1 to 5, characterized in that the pressure measuring device (37) is designed with a flexible membrane (37) in the cassette (1) and the pressure or force sensor in the device (99).

7. Ophthalmologic device (99) according to one of claims 1 to 6, characterized in that a control unit in the device is designed such that the determined infusion pressure of the infusion conveyor device (36) can be adjusted to a target value by means of an automatic control, wherein an adjustment of the target infusion pressure which is dependent on the delivery rate is carried out in such a way in particular that an increased pressure drop caused by the flow velocity in the line to the surgical instrument (29) is compensated.

8. Ophthalmological device (99) according to one of claims 1 to 7, characterized in that said device is formed with a motor-driven height adjustment (32) of the infusion container (30), and switchability for optionally bypassing the infusion conveyor device (36) is provided by a bypass valve device (35).

9. Ophthalmological device (99) according to one of claims 1 to 8, characterized in that the aspiration conveyor device (52) and the infusion conveyor device (36) are constructed in a similar - in particular identical - manner in their design and dimensioning.

10. Interchangeable cassette (1) for an ophthalmological device (99) according to claim 5, comprising: • at least one rigid hard part (41,42,43) as the housing of the interchangeable cassette (1), • at least one elastic soft part (44), wherein the hard part (41, 42, 43) and the soft part (44) form internal liquid channels of the interchangeable cartridge (1) and the soft part (44) is partially accessible from the exterior of the interchangeable cassette (1), and wherein regions of the soft part (44) form peristaltic pump squeezing channels (94) on the cassette side for conveying an infusion medium in at least one of the liquid channels, and wherein regions of the soft part (44) form at least one pressure sensor region (37) on the cassette side for determining a liquid pressure for the infusion medium in at least one of the liquid channels.

11. System consisting of an ophthalmologic device (99) according to one of claims 1 to 9 and an interchangeable cassette (1) according to claim 10.

12. Method for the automatic infusion pressure regulation in an ophthalmological device (99) according to claim 1 for suction flushing, comprising an active aspiration delivery of an aspiration liquid from a surgical instrument (29) to a waste container (56), and an active infusion volume delivery of an infusion medium from an infusion container (30) to an infusion connection (38), comprising a measurement of an infusion pressure of the infusion medium in the device (99), and a regulation of a delivery volume of the infusion volume delivery by means of the infusion pressure, wherein infusion volume delivery and aspiration delivery are each carried out by means of a peristaltic pump.

13. Method according to claim 12, characterized in that the regulation is carried out with compensation of a pressure drop in a line connected to the infusion connection towards the eye, wherein this pressure drop is determined on the basis of a flow velocity of the infusion medium which is determined from the delivery volume.

14. Method according to one of claims 12 to 13, characterized by tuning the delivery volume and a delivery pressure of the active infusion to a characteristic value of the active aspiration with a dependence of a movement of an infusion peristaltic pump on an aspiration delivery volume and on an aspiration delivery pressure of the active aspiration, in particular wherein an aspiration vacuum is determined and a temporary increase in the infusion pressure takes place when the aspiration vacuum increases.

15. Method for the automatic control of an active infusion in an ophthalmological device (99) according to claim 1 for suction flushing by a control unit, comprising: a determination of an aspiration delivery rate of an aspiration of the suction flushing, a pilot control of an infusion delivery rate of the active infusion to compensate for the aspiration delivery rate, a determination of an infusion pressure of the active infusion in the device (99), and a readjustment of the pilot-controlled infusion delivery rate to achieve a desired infusion pressure, which readjustment takes place as a function of the infusion delivery rate, in particular to compensate a pressure drop in a line to a surgical instrument.