Patent ID: 12220519

The depictions in the figures are for illustration purposes only and, unless explicitly stated otherwise, are not to be regarded as true to scale. Identical or functionally similar features shall, as far as practicable, be consistently marked with the same reference numerals and, where appropriate, distinguished by a letter as an index. The diagrams show the basic technical structure, which can be supplemented or modified by a person skilled in the art according to general principles.

FIG.1shows a possible example of a block diagram of an embodiment of an ophthalmological cassette1according to the invention with at least one active infusion according to the invention. In this example, it can be specifically an infusion device in an interchangeable cassette1of an ophthalmological device99, with which suction flushing can be carried out. In the left half of the figure an active infusion device is shown, in the right half an aspiration device.

A container30, e.g. an infusion bottle or an infusion bag, provides an infusion liquid, e.g. a BSS (Balanced Salt Solution) or another infusion liquid. This infusion liquid supply can, for example, be equipped with a device for checking the filling level. For example, the container30, a drip chamber31, a connection tube and or a cassette-internal liquid channel with a wired or wireless sensor can be monitored for emptying. When cassette1is inserted, connection33can be arranged on cassette1so that it can be accessed from the outside and connected to the infusion container30or the interposed drip chamber via a tube, for example.

As known from the prior art, the infusion liquid pressure at the bottle connection33of cassette1(or in the entire infusion system) can optionally be changed by varying the height of the container suspension by means of a height adjustment of the suspension of container30, preferably motorized and automatic, which is symbolized here by the drive32. However, with the active infusion according to the invention, this height adjustment is not absolutely necessary but can be provided as a switchable option and/or as additional safety or redundancy on the device according to the invention.

In the case of another embodiment of a cassette1according to the invention, an active infusion can, according to the invention, be carried out exclusively by means of an active liquid conveyor device36. A pumping device, such as a peristaltic pump or another liquid delivery device in the infusion system, is designed for this purpose. With such an embodiment, an infusion valve35and/or a height adjustment of the infusion container30can optionally be dispensed with. The infusion pressure and/or the delivery volume of the infusion can be varied, in particular controlled or regulated, by appropriate control of the conveyor device36.

Another preferred embodiment of a cassette1according to the invention can also have—as shown in the figure-both an infusion container height adjustment32and an infusion liquid conveyor device36. Cassette1according to the invention can be designed in such a way that the infusion pressure can additionally be adjusted or regulated as described here by changing the height difference between the container30of the infusion site. In particular, a valve35can be designed as a bypass to the conveyor device36. Thus, with the same cassette1, either an active infusion pressure variation (i.e. actively initiated by the conveyor device36) or a hydrostatic infusion pressure variation (i.e. caused by a difference in height) can be provided. In particular, if required, it is possible to switch seamlessly between these two principles—e.g. also during operation—for example according to the current requirements of the operation being performed or according to the surgeon's preferences. Special applications in which two different and independent infusion pressures are required at the same time can also be carried out with such an embodiment according to the invention by applying a first pressure-adjustable infusion by means of the hydrostatic height adjustment via a first line to the eye and a second pressure-adjustable infusion with the active infusion by means of the infusion conveyor device in the cassette via a second line to the eye.

The infusion system according to the invention can also have an infusion pressure measuring device37, by means of which a pressure in the infusion system can be determined, monitored and/or regulated. Preferably, this infusion pressure measuring device37is arranged after the infusion valve35and/or the pumping device36, so that their determined pressure corresponds to that which is supplied to the eye. Since the infusion system can (or at least should) only have overpressure in relation to the atmosphere, this infusion pressure measuring device can be designed in such a way that only overpressure can be determined with it, and not necessarily underpressure (although such a variant would also be applicable). One of many possible examples of a concrete embodiment can be formed, for example, with a part of the infusion liquid channel that has been extended to form a pressure chamber and has a flexible membrane on the outside. When cassette1is inserted, this membrane is in contact with a sensitivity surface of a force or pressure sensor in the device99. The force exerted on the membrane by an overpressure in the liquid channel relative to the atmosphere can thus be determined as a measured value for the overpressure in the liquid channel.

The infusion liquid is provided by means of the cassette1according to the invention with active infusion according to the invention with adjustable pressure and/or delivery volume at an external infusion connection38of the cassette1, which can be connected to a line or a tube to the surgical intervention tool, e.g. the surgical handpiece29, so that the infusion into the eye can be provided with adjustable and/or regulatable pressure and/or volume. In order to guarantee safety, the actual prevailing pressure of the infusion to the patient can be monitored with a corresponding pressure sensor37. If necessary, pressure losses in the line system to the patient can also be taken into account-especially pressure losses due to dynamics, since the delivery volume and thus also the flow rate of the infusion are known according to the invention by the conveyor device36.

In particular, the infusion liquid, for example, can be provided by means of the cassette1according to the invention with active infusion according to the invention with adjustable delivery volume via a volume conveyor device with a defined, known delivery volume at an external infusion connection38of the cassette1, which connection can be connected with a line or a tube to the surgical intervention tool. In order to provide the infusion into the eye with adjustable pressure, the actual prevailing pressure of the infusion towards the patient is monitored with a corresponding pressure sensor37in the device. According to the invention, pressure losses in the line system to the patient can also be taken into account, especially pressure losses due to dynamics, since, according to the invention, the delivery volume and thus also the flow rate of the infusion in the line is known through the conveyor device, on which flow rate a difference between the pressure value at different ends of the line depends in a known way. Especially if a tube diameter, a tube cross-section and/or a tube length of the line are known—which is usually the case with such interchangeable cassettes or sets—a resulting pressure on the eye can be well regulated under consideration of the delivery volume. In particular, with such a direct control of the delivery volume, taking into account the pressure losses in the line, a direct and thus very fast pressure control can be achieved, which has advantageous dynamic characteristic values for this application.

According to a partial aspect of the invention, the arrangement and formation of the liquid channels within cassette1is preferably such that when the liquid channels are filled with liquid, this filling always takes place (at least substantially) from bottom to top—with which any air bubbles (corresponding to the medium density ratio) are displaced upwards and discharged away from the patient and an accumulation of air bubbles is avoided. Such a filling of the liquid channels of cassette1takes place especially after the insertion of cassette1when it is put into operation. 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 bag55—aspiration-A from patient12a,50—optional aspiration-B12b—infusion to patient38—infusion bottle33.

The cassette1according to the invention can have at least one air bubble sensor34in the infusion system, with which a correct function can be monitored and an infusion of air can be avoided. The air bubble detector34can work in particular optically—for example due to 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 active principle, such as a capacitive one, can be used. One example of a concrete embodiment can be formed with a viewing window into the liquid channel that is optically transparent at least in the wavelength used, which can be implemented in an outer shell41,42of cassette1. In one embodiment, for example, the outer shell can be made of transparent material.

Also shown here is an optional path according to the invention from the infusion system to the aspiration system of cassette1, which can be released with a venting valve39. This can be used, for example, to fill the aspiration system with liquid, especially when cassette1is put into operation, and/or to backflush infusion liquid through the aspiration system, for example to loosen occlusions (reflux) or generally to reduce the negative pressure in the aspiration path, e.g. if the physician wishes to reduce the desired negative pressure via the foot switch. For these functionalities, further valves may be available in the cassette for the corresponding switching of the liquid flows.

The aspiration system of the cassette1according to the invention is connected to the surgical intervention tool29via an aspiration connection50with a pipe or tube. Again, at least one air bubble sensor34bcan be present in the aspiration system. The figure also shows an aspiration valve51. In the aspiration system, a pressure measurement can also be carried out with a pressure measuring device10, which can, however, measure both negative and positive pressures with respect to the atmosphere. In order to detect forces in both positive and negative directions accordingly, the pressure measuring membrane of the cassette must be connected to the corresponding pressure measuring sensor in the device to transmit both positive and negative values. Examples of such known pressure detection devices can be found, for example, in patent application EP 16197018 filed on the same day by the same applicant, which is hereby included by reference, or possibly also in the references cited therein.

To achieve the aspiration effect, the figure shows two variants, i.e. on the one hand a peristaltic aspiration and on the other hand a Venturi aspiration. An embodiment of a cassette1according to the invention may either exhibit only peristaltic aspiration, or another embodiment of cassette1according to the invention may comprise only Venturi aspiration, or another embodiment according to the invention may comprise both peristaltic aspiration and Venturi aspiration.

In Venturi aspiration, the aspiration effect is caused by an air vacuum, which is usually generated by a name-giving Venturi nozzle or a vacuum pump. These variants are symbolized here by the Venturi valve57and the vacuum system58. In particular, a so-called “Clean Venturi” system can also be applied, which is described in the international application EP 16196998 filed on the same day by the same applicant and is hereby included by reference. In the case of Venturi aspiration, a measured value of the aspiration vacuum in particular can be used as the basis for controlling the active infusion conveyor device36, e.g. as described below. In particular, the active infusion conveyor device36according to the invention can be controlled and/or regulated on the basis of currently prevailing infusion pressure and currently prevailing aspiration vacuum by a control unit provided for this purpose. Optionally or alternatively, the control unit can also include values of a current delivery rate of the infusion and/or aspiration.

In peristaltic aspiration, a liquid conveyor device52is used to generate the aspiration effect. The delivery device52can in particular be a peristaltic pump, but optionally a membrane pump or other liquid delivery devices can also be used. The aspirated liquid is preferably pumped into an appropriate waste container56, which is preferably connected to an appropriate waste connection55outside cassette1. Again, a pressure sensor37c, especially for overpressure, can be used to detect a pressure increase with a full waste bag.

Cassette1, in accordance with the invention, may also have a coding70, in particular mechanical and/or optical, which can be recorded and evaluated by a corresponding reading unit71of the device99. This coding can be used to prevent multiple or non-sterile use, for example with disposable cassettes, and a specific embodiment of the inserted cassette and its optional functionalities etc. can be detected by the device99.

In special vitrectomy procedures, when the vitreous body is removed, a gas, usually room air cleaned with a bacteria filter from the OR, is first pumped into the eye, usually with an overpressure of approximately 20 to 120 mmHg. As a result, this pumped-in air is then replaced by a silicone oil, which presses the detached retina back onto the choroid so that it can grow back again. In the prior art, an air pump specially designed for this purpose is required in the device for this purpose, which, however, is very rarely actually used. If a peristaltic pump is used specifically for infusion as the active conveyor device36in accordance with the invention, this pump can also be used for conveying gases instead of infusion liquid. This not only results in a simpler device design by dispensing with the special air pumping device but also has advantages in terms of hygiene and sterility, as the interchangeable cassette1is sterilized and is also regularly replaced. As an optional accessory, a preferably sterile and/or single-use bacteria filter can, for example, be attached to the bottle connection of interchangeable cassette1, which filters the infusion air sucked in in this case.

FIG.2shows another exemplary embodiment of a cassette1according to the invention in a block diagram. The features functionally identical or equivalent toFIG.1are provided with the same reference numerals and reference is made to their description above.

The main differences between this embodiment according to the invention andFIG.1are, according to the invention, that in the infusion area only one active infusion is carried out by means of a conveyor device36. The infusion valve35is here only optionally designed as an additional shut-off against the patient—but can also be omitted, especially if the liquid conveyor device36already has a sealing effect. The infusion path additionally shows an optional passive or active ripple compensation element59for a peristaltic pump36, which is not absolutely necessary according to the invention. A passive compensation can, for example, be formed with a flexible area of the liquid channel which has the effect of a balancing bellows which cushions the pressure or flow rate ripple by deforming according to the ripple. Alternatively or additionally, active ripple compensation can be applied, in which an actuator on the device side deforms a flexible area of an infusion liquid channel and thereby compensates for pressure or flow rate ripple effects. The actuator can be controlled, for example, on the basis of values from the pressure sensor37and/or information about the rotary position of the peristaltic pump36. According to the invention, a dynamic variation of the rotational speed of the peristaltic pump can also take place in such a way that the ripple effect of the conveyor device is minimized. In contrast to a normal, uniform rotational movement (with an optionally accelerated or decelerated phase in the case of changes in flow rate) as applied in the prior art, no strictly uniform rotational movement of the roller head takes place during conveying, but the rotational speed is modulated with the period duration of the roller interventions in such a way that the flow rate ripples occurring with this period duration are compensated as far as possible. Thus, a temporary acceleration or deceleration of the roller head movement occurs when a roller enters the area of the inlet or outlet of the squeezing channel (inlet or outlet, depending on which side of the ripple is to be compensated, i.e. when feeding or suctioning).

In the aspiration area, the waste bag56can be attached directly to cassette1in accordance with the invention. In addition to the aspiration connection50a, a second, optional aspiration connection50bwith corresponding aspiration valves51band50bis also shown for selection. In a Venturi system, the optional pressure sensor10bcan additionally monitor the pressure in the suction chamber of said system.

According to the invention, the infusion pressure can also be adjusted much more quickly than is possible with prior art technology. This can be done in particular depending on the surgical step or special circumstances that occur during the operation.

With the data known according to the invention which relate to the flow rate of the active infusion as well as 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.

The embodiments of an active infusion according to the invention described here offer a number of advantages over a known infusion system, such as a gravity infusion or an infusion by pumping air into the infusion surface. In particular, an active infusion according to the invention, especially with a peristaltic pump, offers advantages such as:Simplification of the setup of the operation and the commissioning of the device—and thus time saving, especially since an initial filling of the infusion system is designed significantly easier and faster.Reduced risk of sterility errors, especially when setting up the device.Faster pressure changes during the intervention than in the prior art can be carried out, which offers many application possibilities not known until then.Independence from a special supply of the infusion liquid, especially with regard to bottle size and bottle type, as this has no effect on the active infusion according to the invention.Additional monitoring functionalities, parameter evaluations, safety and comfort functions, etc. can be implemented.There is less waste because air filters, long needles for the infusion set, tubes, packaging etc. can be saved. Only the interchangeable cassette, which is required for aspiration anyway, is required, which can optionally be designed to be sterilizable several times. The costs of consumables will also be reduced.

FIG.3aandFIG.3bshow a further embodiment of a cassette1according to the invention, each in a view from the right and left front. In the figures, the functional elements already described in the block diagram are shown and marked again. In this example, cassette1is shown as a basic cassette1a, at least approximately cuboid in shape in its outer contours, with a projecting plate as the front section1b. On the front section1bthere are connections for tube systems, in particular those to the surgical handpiece, to the infusion liquid reservoir30, and to a waste bag56. Preferably these connections33,38,50,55are mechanically and/or geometrically coded as shown in order to exclude the danger of incorrect connection and confusion.

In the example of an embodiment shown here, the functional elements of cassette1are divided between both of the shown outer shell halves41and42of cassette1, thus enabling a compact structure to be achieved. The squeeze pump sections36and52are especially arranged on one cassette side42, and the valves and pressure sensors are arranged on the opposite cassette side41. Such a division of the functional elements is not mandatory, but can be advantageous with regard to gripping or clamping cassette1in device99, in which clamping, fixing and/or fine positioning of cassette1in device99can take place simultaneously with pressing of the roller head(s) of the peristaltic pump. The movement required to clamp the cassette in the device99can only be carried out from one side, preferably from the side of the peristaltic rolls. The following figures illustrate in detail another exemplary design of a peristaltic pump according to the invention of a cassette1according to the invention.

FIG.4shows an exemplary embodiment of a cassette1according to the invention in its end position in a cassette slot of a device99. Cassette1was inserted by pushing it into the cassette slot in insertion direction91and can be done manually or at least partially automated or motorized. A part of the cassette slot is shown as a section, but cassette1is shown in a non-sectional manner. In the illustrated position of cassette1in device99, rollers can press against the squeezing areas of peristaltic pumps36and/or52, essentially orthogonal to the shown side of cassette1in direction27, so that cassette1can be positioned and fixed according to the invention in device99at the same time. In this inserted state, the sensors and actuators on the device side are in a position with respect to the cassette in which they can interact with their respective associated functional elements of cassette1for the intended purpose.

FIG.5schematically shows such a clamping and fixing of the inserted cassette1in the device99in a side elevation view, with viewing direction at the peristaltic pumps of cassette1(direction27inFIG.4). A roller head72on the device side with rollers73is shown, which rollers73roll on the bulging squeezing area94of the outer shell42, which is formed of elastic soft plastic44. With this unrolling, the squeezing area94is pressed by the rollers73sealingly onto the core part43of cassette1and, with a rotation of the roller head72around the rotation center75, a volume in the squeezing area94between the rollers73is conveyed. For the rotation of the roller heads72, the device99has a respective infusion drive76for the infusion conveyor device36and an aspiration drive77for the aspiration conveyor device52.

InFIG.6a, cassette1is inserted in insertion direction91, which in this figure runs orthogonally to the drawing plane, into device99up to its end position, but is not yet clamped. This concerns a sectional view of the right and left rotation centers75aand75bof the two separate peristaltic pumps36and52fromFIG.5. In the example shown, cassette1shown in the section is essentially made up of three parts, with a left outer shell41, a right outer shell42and a core part43. Preferably the outer shells41and42are designed to be snapable, compressible or squeezable against each other and/or against the core part43, e.g. with a hook system, a press-fit system or similar, which in particular cannot be designed to be detachable again. In this case, the outer shells41and42can in particular be designed as two-component injection-molded parts consisting of a rigid hard plastic component and an elastic soft plastic component. The elastic soft plastic part is then clamped and squeezed and/or positively engaged with the core part43so that the liquid channels or pipes are formed and sealed within cassette1. In the section shown, the elastic portion44forms beads along the liquid channels which, in the assembled state, engage in depression in the core part43—thereby effecting a liquid seal, in particular by squeezing the soft plastic44and/or forming a meander seal with at least one step. Partial areas of the soft plastic part44are accessible from the outside when cassette1is assembled and form the functional elements. The hard plastic part of the two-component injection-molded outer shells41and42has corresponding cut-outs for this which provide access to the soft plastic44. Optional sterilizability of the entire cassette, for example in the autocalve, etc., can also be taken into account when selecting the cassette materials if a reusable embodiment is desired.

In this example of an embodiment according to the invention, cassette1is clamped after insertion and the roller heads72of the peristaltic pump are pressed in direction83. As shown, the clamping force of the rollers73and/or the position alignment82can be determined by means of springs.

The actuators which are not visible here and which act on the valves35,39,51,51a,51band/or57are also arranged in device99in accordance with the invention and are designed, for example, as electromagnetically or electromotively or pneumatically actuated plungers in the device which act mechanically on the valve formations of cassette1. The pressure sensing device10, especially its coupling element, is also coupled in the inserted state of cassette1with the force sensor11on the device side, which is not shown here. As also the membrane on the cassette side of the pressure sensor37and/or37cis brought into a functional operative connection with a force or pressure sensor on the device side.

FIG.6bshows cassette1in clamped state in device99, in which all sensors and actuators of device99correspond with their counterparts of cassette1for interaction. In the example shown, this is done by clamping cassette1in device99by pressing roller heads72against cassette in direction83. Thus the cassette1is pressed in the drawing level to the left on corresponding mechanical stops. The rollers73squeeze the squeezing channels94—wherein in the upper pump (e.g. the infusion pump36) there is a section through the roller73with a squeezed squeeze cross-section94and in the lower pump (e.g. the aspiration pump52) there is a section next to a roller73and correspondingly an unsqueezed squeezing cross-section94. With the centering elements82, which in this example also form the rotation axis75of the roller head72, fine positioning of cassette1in device99is also achieved when cassette1is clamped.

FIG.7ashows an exemplary embodiment of a cassette1according to the invention in which a cassette-side pumping device36for the active infusion according to the invention and a further pumping device52are shown.

The illustration shows a first pumping device36for infusion and a second pumping device52for aspiration, separate from the first pumping device. These pumping devices are formed with the soft areas44of the outer shell42, which form outwardly curved squeezing channels94. As a result of the intervention of rollers73, these squeezing channels94are pressed locally sealingly onto the core part43. By moving the roller73along the squeezing channels94a volume can be conveyed in the squeezing channels94. This movement can be achieved by rotating a roller head72around the rotation axis75b, wherein the roller head72carries the rollers73aand73b. Especially shown are the rollers73cand73don the device side, which move on concentric circular paths and engage in the respectively assigned squeezing channels94cand94don the cassette side and form the pumping device52in cooperation with these. The same applies to the pumping device36, wherein for the sake of clarity the rollers assigned to the squeezing channels94aand94bare not shown here.

A partial aspect that can be carried out according to the invention in this specially further developed embodiment for the reduction of ripple effects is the dual pump design with at least two adjacent squeezing areas94cand94d. These are designed and arranged in such a way that the ripple of the two adjacent squeezing channels94cand94doccurring due to the squeezing pumping effect is compensated as much as possible and thus the overall ripple of the pump is reduced. As shown, this can be achieved, for example, by mutually offset squeezing rollers73cand73d, which cause a phase shift of the pressure or flow rate ripple generated by the two squeezing channels94cand94d. The two inlets and the two outlets of the squeezing channels94cand94dare hydraulically connected to each other. In particular, a phase shift of the ripple curves by approx. 180 degrees for two channels can result in an advantageous reduction. With a different number of squeezing channels94, the phase shift must be selected accordingly in a different manner. Alternatively or additionally, the position and/or shape of the inlets and/or outlets of the two squeezing areas94can be designed differently in order to effect said phase offset and/or a further ripple reduction. Thus, a ripple reduction can be achieved in relation to a single squeezing area according to such a further developed embodiment with a corresponding design.

In the case of an at least near concentric arrangement of two interconnected squeezing channels94cand94dwhich are shown here, it can also be considered that with their different arc radii also different arc lengths occur. For ripple compensation, the liquid channel cross-sectional dimensions, cross-sectional shapes and/or cross-sectional progressions of the outer arc94ccan therefore be designed in accordance with the invention so differently from the inner arc94dthat the volume conveyed per movement unit of the rollers73always remains at least approximately the same—or the volumes always balance each other out as far as possible and together result in the smallest possible ripple of the total volume conveyed, e.g. in such a way that over a complete revolution of the roller head carrying the rollers73, the outer and the inner squeezing paths94cand94dconvey at least approximately the same volume or have as far as possible a diametrically opposed volume ripple. Due to optionally different diameters of the engaging rollers73cand73d, different squeezing radii can also be taken into account in these considerations.

FIG.7bshows the embodiment ofFIG.7aagain in a sectional view through cassette1. The liquid channels in the area of the peristaltic pump are formed in the interior of cassette1by the hard plastic core part43, over which an elastomer part44aof the outer shell42curved towards the exterior of cassette1forms a partial area of the liquid channel. This partial area, which is also referred to as squeezing area94of the pump, can be squeezed by engaging rollers73on the device side in the mode of action of a peristaltic pump so that the liquid or air in the liquid channel can be pumped when the roller73is moving. In particular, according to the invention, the cross-sectional area of the squeezing area94formed in this case can vary over its length. As shown in this example of an embodiment according to the invention, a taper of the cross-section towards the outlet of the pump and/or an enlargement or reduction of the (unsqueezed) cross-section at the inlet of the pump may be possible. In particular, an optimization of this change in cross-section can minimize pressure and/or flow rate fluctuations (also known as ripple) during conveying. An advantageous cross-sectional profile along the squeezing area94can also be determined, for example, by means of simulation and/or test series.

FIG.8ashows cassette1with exemplary roller heads72in engagement. For the sake of clarity, only the lower rotatable roller head72b, to which the rollers73bare attached, is indicated in the figure—in the case of the upper pumping device, only the rollers73abut not the associated roller head72aare shown. In the example shown here, a first roller head72aand a second roller head72bof the respective separate infusion and aspiration pumps intervene on the same side of cassette1. In another embodiment, the first and second roller heads72aand72bcan also engage on opposite sides of cassette1. In particular, but not necessarily, the rotary axes of the roller heads can be arranged opposite each other and form an at least approximately common rotary axis, which can bring advantages with regard to force distribution on cassette1.

In this embodiment according to the invention, the squeezing areas are each only single, i.e. formed without a hydraulically parallel second squeezing channel as in the previous embodiment fromFIGS.7aand7b.

In the example of the embodiment according to the invention shown here the two pumps36and52describe in each case at least approximately a semicircle on cassette1. This results in an advantageous use of space on cassette1shown here by way of example, especially with simple handling and producibility. A concentric arrangement of the two pumps36and52, which can also be implemented, would also be possible but would be comparatively more complex in terms of design. Alternatively, the beaded squeezing area94of the pump36and/or52can also be designed in a different embodiment with a different, in particular shorter arc length, wherein, however, an appropriate arrangement and number of rollers73aor73bmust always be selected so that sufficient pumping behavior can be ensured, i.e. in particular in each squeezing area94, at least one, preferably more than one, roller73ais always engaged.

As illustrated inFIG.8b, this can be achieved, for example, in accordance with the invention, by arranging the roller axes74at an angle to their unrolling planes on the squeezing channels94, and preferably intersecting with this unrolling plane in the center of rotation75of the roller head72carrying the rollers73. The frustoconical rollers73thus roll optimally onto the soft plastic area44bof the outer shell42, which forms the squeezing channels94, and squeeze this against the core part43. Alternatively, other geometries can also be used. The forming and arrangement are preferably carried out in such a way that the circumference of the roller73aor73bat one point is respectively proportional to the circumference of the circular path described by the roller at this point around the pivot75aof the center of the roller head72a.

FIG.9shows an exemplary embodiment of an example of an interdependent control according to the invention of the infusion conveyor device and aspiration conveyor device according to the invention. At the beginning the “normal state” is shown, where the infusion pressure P-inf is at least approximately constant and the aspiration volume V-asp is also at least approximately constant—e.g. an aspiration peristaltic pump rotates at an average constant speed. As a bar on the abscissa, which represents a time axis, an occlusion of the aspiration tool is shown, i.e. when a shattered lens particle clogs the tip of the suction needle, for example. This causes the aspiration negative pressure in the device to rise as shown on the corresponding curve. In accordance with the special partial aspect according to the invention described here, the infusion pressure can now be increased as a precaution in such a case with the rapid, dynamic controllability of the infusion pressure with the infusion conveyor device according to the invention from a certain aspiration vacuum, as shown in the corresponding curve. This can be carried out automatically by a control unit in device99, i.e. without the intervention of a doctor. This occurs in preparation for the expected fracture of the occlusion, i.e. when the occlusion dissolves and the suction needle becomes free again—i.e. at the end of the occlusion bar shown. Then, due to the increased aspiration negative pressure, the aspirated liquid quantity is briefly increased-which could lead to an (at least slight) collapse of the eye. However, this can be compensated to a large extent by the partial aspect according to the invention of the precautionary, temporary increase in infusion pressure, since more infusion liquid has already been pumped during the occlusion detected (e.g. in the aspiration pressure increase) as a precaution in this case. Thus, when the occlusion is released, there is sufficient liquid in the eye so that collapse (=collapse of the anterior chamber) can be prevented or at least reduced. After loosening the occlusion and returning to the normal state of the aspiration negative pressure, the infusion pressure can also be normalized again.

FIG.10shows an exemplary embodiment of an example of a dynamic adjustment of the infusion pressure with which the active infusion according to the invention as the partial aspect according to the invention can be carried out. A diagram is shown in which, by way of example and simplified to the basic principle, the delivery volume F-asp of the aspiration conveyor device and the delivery volume F-inf of the active infusion conveyor device, which is controlled dependent thereon according to the invention, are shown. This dependency is illustrated here in an exemplary manner in such a way that the infusion is controlled as a function of a predetermined aspiration—in the sense of the invention, however, it is also possible to implement embodiments in which the desired infusion is predetermined and the aspiration is controlled as a function of this. In the diagram, the infusion quantity is always slightly larger than the aspiration quantity, since leakage losses are compensated when the eye is opened. The shown dependence on infusion and aspiration is preferably used as a kind of pilot control, which can additionally be superimposed by a regulation of the actual infusion pressure.

The regulation is thus simplified and can be formed more dynamically, since the control deviation to be compensated is only small. In addition, with a significantly longer time constant, the pilot control can also be slowly adjusted according to the actual leakage loss if necessary and adapted to the actual losses occurring during the specific operation. For example, at the beginning of the intervention the pilot control can be carried out with a leakage rate compensation of 7%, for example, which is usual for this intervention according to experience, which percentage is then e.g. adjusted to 5%, if the superimposed regulation causes a continuous reduction of the infusion quantity over a longer period of time—the intervention opening is thus tighter than usually assumed.

In the upper part of the diagram, the infusion pressure P-sens at the pressure sensor in the cassette, corresponding to the infusion flow rates F-inf and adapted according to the invention, is also shown. The shown increase of the infusion pressure P-sens in the cassette, which is carried out according to this aspect of the invention depending on an increase of the flow rate F-inf, in particular an increased pressure drop in the line to the patient due to flow velocity is compensated for and results in a more balanced, more constant infusion pressure P-inf in the eye than in the prior art. Parameters for this flow rate-dependent target infusion pressure adjustment, e.g. the curve of the adjustment P-sens, can be determined, stored and provided experimentally or computationally for a tube set used in each case.

In the prior art, without active infusion, the above-mentioned advantageous further developments cannot even be taken into consideration, since such prior art systems reacting with inertia cannot be implemented. In addition, the problems which these advantageous further developments solve are not even known in the prior art or are of obvious relevance.

Another prior art problem is that relatively thin tubes are often used for the infusion, and therefore the pressure drop between the BSS bottle and the device cannot be neglected, especially with high infusion flow rates. It also happens frequently that a negative pressure forms in the BSS bottle, which has a negative effect on the infusion pressure in the prior art. A filter in the drip chamber, for example, which causes too much pressure drop, also has a negative effect. In these cases, gravity infusion results in less pressure in the eye and thus less stability.

With the active infusion according to the invention all this does not play a role, since the above problems do not, or at least hardly, affect the infusion pressure in the eye, or are actively compensated by the active infusion.

In particular, pressure measurement on the patient side of the liquid delivery device together with pressure regulation via a peristaltic pump can compensate for the pressure losses mentioned above. In addition, the peristaltic pump can also have a suction effect from the direction of the BSS bottle, which means that the flow rate can be compensated even with high pressure drops in the line, drip chamber, infusion bottle, etc. According to the invention-if necessary-higher flow rates from the BSS bottle can also be achieved than with just a gravity infusion, which can be very helpful in some surgical situations. In particular, it is possible to react quickly and dynamically to any changes, which makes the operation safer. In particular, according to the invention, such a fast and dynamic reaction to possible disturbances can be carried out automatically by the device, i.e. without or with only minor intervention by the personnel, especially via a controller module for the control of the infusion liquid delivery device, which automatically maintains or runs down predetermined target values and/or target value profiles of the infusion pressure on the basis of the sensor technology of the interchangeable cassette.

According to the invention, the infusion pressure measurement is thus arranged in the device, especially in the interchangeable cassette, especially in the flow direction of the infusion after the infusion conveyor device and before the infusion connection of the interchangeable cassette. In accordance with the invention, the control of the infusion—or the regulation of the infusion pressure at the remote surgical instrument connected via the line—is carried out exclusively via the control of a motor drive of the infusion conveyor device, which provides a volume conveying with a defined, known delivery volume. According to the invention, only one pressure sensor in the change cassette is required, since pressure drops are compensated via the line on the basis of the known delivery volume and the resulting flow rate or the flow velocity of the infusion medium through the line. Therefore, no special handpiece or surgical instrument is required for the infusion according to the invention, and in particular only a fluidic and no electrical connection. In addition, according to the invention, for example when an occlusion in the aspiration path is detected by an aspiration pressure sensor attached to the aspiration path, a pressure change in the infusion can occur which is especially dependent on the aspiration and which is especially also preventive. According to the invention, a leak rate compensation of the known infusion volume in comparison to a known aspiration volume can also be formed, for example by controlling the infusion conveyor device with a defined higher known delivery volume than that of an aspiration conveyor device and/or always providing a defined minimum delivery volume of the infusion.

In other words, one embodiment of the invention relates to a method with remote sensing pressure regulation at an infusion point connected to a conveyor device via a line, in which a pressure drop in the line is determined depending on a delivery volume of the infusion medium and a target value for a pressure of the infusion medium at the conveyor device is adjusted accordingly. In particular, this can be carried out, for example, by detecting a pressure of the infusion medium by means of a pressure sensor in the device arranged between the peristaltic pump and a connection to the line, and increasing a target value of the pressure as a function of the delivery volume to compensate for a pressure drop in the line, especially when these methods are provided in an ophthalmological device.

In other words, in an ophthalmological device an infusion pressure at the end of an infusion tube—i.e. the eye—can be determined according to the invention by knowing a pressure in the device and a flow volume for a known infusion tube. In comparison with pressure measurement directly on the eye for example, this is not only easier to install and less prone to errors but also results in an advantageous pressure regulation behavior for this specific application.