Implantable ocular drainage device for controlling intraocular pressure

Abstract

The present invention relates to an implantable ocular drainage device for controlling intraocular pressure (IOP), comprising at least one drainage channel and at least one magnetic control mechanism, the at least one magnetic control mechanism being a magnetic valve mechanism configured to regulate flow in the at least one drainage channel.

Description

Technical Field

[0001] The present invention relates to an implantable eye drainage device for controlling intraocular pressure, comprising at least one drainage channel and at least one magnetic control mechanism.

Background Art

[0002] Glaucoma is an eye disease and a major cause of preventable blindness worldwide. An increase in intraocular pressure (IOP) is considered a major risk factor for glaucoma and is associated with an imbalance between the production and drainage of aqueous humor due to an abnormal increase in the resistance to the outflow of aqueous humor. Glaucoma drainage devices (typically hollow tube-shaped shunts surgically implanted into the eye) provide an alternative pathway for effectively draining aqueous humor and reducing intraocular IOP. However, the postoperative IOP is unpredictable, and often conventional shunts cannot maintain the IOP at an optimal level. The reason behind this is that the drainage of aqueous humor depends on the fixed hydrodynamic resistance of the shunt. However, often when the postoperative IOP changes, the fixed hydrodynamic resistance of the shunt becomes inappropriate, and if the resistance is too high, it can lead to too high intraocular IOP, and if the resistance is too low, it may lead to undesirable over-drainage.

Summary of the Invention

Problems to be Solved by the Invention

[0003] A magnetic drive control mechanism for a known ocular drainage device is disclosed, for example, in WO2019 / 051475. This known device comprises a mobile magnetic element, which can be driven by the application of an external magnetic force from a first position in which the element allows free flow through a drainage tube to a second position in which the mobile element slows or blocks the flow through the drainage tube. This known device provides a magnetic drive control mechanism configured to regulate IOP after the ocular drainage device has been implanted. However, a drawback of the known ocular drainage device is that it requires at least two stationary magnets and separate moving space for the mobile element within the housing.

[0004] The object of the present invention is to provide an implantable ocular drainage device for controlling improved intraocular pressure, comprising a magnetic control mechanism, and / or a simpler and more compact implantable ocular drainage device. [Means for solving the problem]

[0005] This objective is achieved by an implantable ocular drainage device as defined in claim 1.

[0006] An implantable ocular drainage device for controlling intraocular pressure comprises at least one drainage channel and at least one magnetic control mechanism. The at least one magnetic control mechanism is a magnetic valve mechanism configured to restrict flow in at least one drainage channel. The magnetic valve mechanism comprises at least a partially movable magnetic valve element provided in at least one drainage channel and a magnet outside the at least one drainage channel for providing magnetic attraction to the at least partially movable magnetic valve element to control flow in the drainage channel.

[0007] The magnets of the magnetic microvalve mechanism may be located near or positioned close to the drainage channel into which the magnetic valve element of the magnetic microvalve mechanism is integrated. At least one magnetic control mechanism requires only one magnet to control the flow through at least one drainage channel. This allows for the provision of an improved implantable ocular drainage device that can be made relatively compact. In addition, the number of components of the implantable ocular drainage device is relatively small, making it possible to provide a simpler device. Furthermore, by using a magnetic valve mechanism, at least a partially movable magnetic valve element is provided in at least one drainage channel, so little or no additional space is required in the device for the magnetic valve element. The magnets provide an attractive force acting on the magnetic valve element. Under the influence of this magnetic attraction, the at least partially movable magnetic valve element can be driven to control the flow in the drainage channel. Thus, the magnetic microvalve mechanism helps prevent or overcome hypointraocular pressure (low IOP) by, for example, allowing for the restriction or blockage of aqueous humor flow through the ocular drainage device. Low intraocular pressure is not uncommon, for example, in the initial postoperative period. If intraocular pressure rises again after this initial period of low intraocular pressure, the magnetic valve mechanism is configured to facilitate flow by driving the magnetic valve element, at least partially, to an at least more open position under the influence of the magnetic attraction of the magnet, in order to allow or increase flow through the drainage channel and maintain intraocular pressure at a healthy level.

[0008] In one embodiment, a magnetic valve mechanism is configured to self-regulate flow in at least one drainage channel. The magnetic valve element is automatically driven in at least one drainage channel to control flow in the drainage channel in response to intraocular pressure. The magnetic attraction of the magnet on the magnetic valve element allows the magnetic valve element, and thus the magnetic valve mechanism, to be open or partially open when the pressure is above a certain pressure threshold, and to remain closed when the pressure is below this threshold. In other words, a self-regulating, passive, implantable ocular drainage device is proposed. Such a device uses a magnetic microvalve mechanism that self-regulates the flow of aqueous humor through the implant in response to intraocular pressure. This magnetic valve mechanism does not rely on an external signal for pressure control; that is, the pressure in the drainage channel itself is used as the driving signal for the magnetic valve element to open and close the drainage channel. In addition, this implantable ocular drainage device also includes minimal components and / or components that require relatively small volumes in the device, so that the self-regulating device is relatively compact and / or relatively easy to manufacture. In addition, in contrast to WO2019 / 051475, in which the magnetic element can only be driven between the "on" or "off" position by the use of an external magnetic force (more specifically, the movement of a mobile element in moving space toward one of two predetermined positions near a stationary magnet), the magnetic valve element of a self-regulating magnetic valve mechanism can take on more than two positions. At least one magnetic valve element of a self-regulating passive implantable ocular drainage device can be displaced by intraocular pressure to the maximum open position, the maximum closed position, and positions in between. Thus, the self-regulating passive implantable ocular drainage device can respond immediately to changes in intraocular pressure, so that the intraocular pressure can be continuously maintained at a healthy value.

[0009] In a further embodiment, the magnet is adapted to displace between predetermined positions relative to the magnetic valve element in response to fluctuations in the magnetic attraction on the magnetic valve element. This offers the advantage of being able to adapt the device to the patient's condition by moving the magnet relative to the magnetic valve element in the device before implantation. After implantation, the magnet is provided in the implantable ocular drainage device to provide a constant magnetic attraction on the magnetic valve element. However, if, for example, the intraocular conditions change after implantation and adjustment of the magnetic attraction on the magnetic valve element becomes necessary, the device can also be adapted to move the magnetic valve element to a different predetermined position to change the device's hydrodynamic resistance after implantation. After adjustment by moving the magnet relative to the magnetic valve element, the magnetic attraction on the magnetic valve element becomes constant again. The device may also be equipped with a stationary magnet that cannot be displaced so that the magnetic attraction on the magnetic valve element remains constant and is not affected by the displacement of the magnet relative to the magnetic valve element. [Brief explanation of the drawing]

[0010] The present invention will be described in more detail below with reference to the attached figures illustrating exemplary embodiments.

[0011] Figures 1A and 1B schematically show a first embodiment of an implantable ocular drainage device.

[0012] Figures 2A-C schematically show a second embodiment of an implantable ocular drainage device in cross-sectional view.

[0013] Figures 3A and 3B schematically show a third embodiment of an implantable ocular drainage device in a top view.

[0014] Figures 4A-C schematically show a fourth embodiment of an implantable ocular drainage device.

[0015] Figures 5A-D schematically show a fifth embodiment of an implantable ocular drainage device. [Modes for carrying out the invention]

[0016] In the following description, the same or corresponding parts have the same or corresponding reference numbers. Each feature disclosed with reference to a specific drawing may be combined with other features disclosed in this disclosure unless it is obvious to a person skilled in the art that these features are incompatible.

[0017] Figures 1A-3B show an implantable ocular drainage device 1;101;201;301;401 for controlling intraocular pressure. Device 1;101;201;301;401 comprises drainage channels 3;103;203;303;403 and a magnetic control mechanism. The magnetic control mechanism is a magnetic valve mechanism 4;104;204;304;404 configured to restrict flow in the drainage channels 3;103;203;303;403. The magnetic valve mechanism 4;104;204;304;404 comprises a magnetic valve element 5;105;205;305;405 provided in the drainage channel 3;103;203;303;403 that is at least partially movable, and a magnet 7;107;207;307;407 provided outside the drainage channel 3;103;203;303;403 to provide magnetic attraction to the magnetic valve element 5;105;205;305;405 that is at least partially movable, in order to control the flow in the drainage channel 3;103;203;303;403.

[0018] Device 1;101;201;301;401 further comprises housing 9;109;209;409 (not shown in Figures 4A-C), where drainage channels 3;103;203;303;403 extend between the inlet side 11;111;211 of housing 9,109,209;409 and the outlet side of housing 9;109;209. The inlet and outlet sides may be on the same side of the housing (not shown). In the shown embodiment, at least one drainage channel 3;103;203;303;403 is connectable to or connected to a drainage tube 21 that collects aqueous humor from the anterior chamber (not shown) during use. In addition, the schematically illustrated housings 9,109,209;409 may actually have different arrangements (e.g., an arrangement adapted to the eye or an efficient implant procedure (e.g., round)). The magnetic valve elements 5;105;205;305 are located within chambers 25;125;225;325;425, which have a larger cross-sectional area than the drainage channels 3;103;203;303;403, and the chambers 25;125;225;325;425 are integrated within the drainage channels 3;103;203;303;403.

[0019] The magnetic valve mechanism 4;104 shown in Figure 1A-2C is configured to self-regulate flow in at least one drainage channel 3;103. Here, the magnetic valve element 5;105 is automatically driven in a chamber 25;125 that forms part of the drainage channel 3;103 to control flow in the drainage channel in response to intraocular pressure. The magnetic attraction of the magnet 7;107 on the magnetic valve element 5;105 allows the magnetic valve element 5;105 to be open or partially open when the pressure is above a certain pressure threshold, and to remain closed when the pressure is below this threshold. Device 1;101 uses a magnetic microvalve mechanism that self-regulates the flow of aqueous humor through the implant in response to intraocular pressure. The magnetic valve element 5;105 can be displaced by intraocular pressure to the maximum open position (high IOP), the maximum closed position (low IOP), and positions in between (moderate IOP) to advantageously maintain the intraocular pressure at a healthy value. A magnetic valve mechanism 4;104 is provided within the chamber 25;125. That is, the chamber 25;125, including a magnet 7;107 and a magnetic valve element 5;105, is located within the housing 9;109. The magnetic valve element 5;105 is a partially movable flap located within the chamber 25;125, forming part of a drainage channel 3;103. The flap is adapted to provide more / less flow through the drainage channel as intraocular pressure rises / falls. One side 5a;105a of the flap is fixed immovably, while the opposite side 5b;105b of the flap can be driven to open and close the drainage channel 3;103 to restrict flow. One side 5a of the flap, as shown in Figures 1A,B, is connected to the chamber 25 in a swivel manner so that the opposite side 5b can move to a closed position (Figure 1B) or an open position (Figure 1A) in response to intraocular pressure. One side 105a of the flap shown in Figures 2A and 2B is fixed immovably to the wall of the chamber 25 so that the opposite side 5b can move by bending to a closed position (Figure 2A) or an open position (Figure 2B) in response to intraocular pressure.Due to the limitations of the illustration in Figures 1A-2C, it is difficult to observe that the valve elements 5;105 can also be positioned between the closed and open chambers 5, 25. However, these devices 1, 101 can handle moderate pressures (i.e., moderate IOPs) by, for example, partially closing the chamber outlet 126 (Figure 2B) with the valve element 105, or by using multiple chamber outlets (not shown) that can be opened and closed independently by the valve elements. Figure 2C shows a cross-section of device 101 from a different side than Figures 2A and 2B. Here, the valve element 105 is shown near the closed position of the valve element 105 shown in Figure 2A. In the incompletely closed position of the valve element 105 in Figure 2C, flow occurs through the drainage channel 103 between the inlet side 111 and the outlet side 113 of the housing 109. However, this flow is a weakened flow through the drainage channel 103 compared to the flow through the valve element 105 in a more open position, as shown in Figure 2B, for example.

[0020] The permanent magnet 7 of device 1 (Figures 1A, B) can be displaced between predetermined positions (not shown) relative to the magnetic valve element 5 in response to fluctuations in the magnetic attraction force on the magnetic valve element 5 (indicated by arrow P1). The magnet 7 can be displaced to adapt or adjust the magnetic attraction force on the magnetic valve element 5 according to the specific patient's condition. After implantation of device 1 into the patient, the magnet 7 is provided in device 1 to provide a constant magnetic attraction force on the magnetic valve element 5. However, it is also possible to reconfigure device 1 after implantation by moving the permanent magnet 7 to other predetermined positions to change the hydrodynamic resistance of device 1. For example, the permanent magnet 7 can be displaced non-invasively within the housing 9 by using an externally provided magnetic field (not shown), as indicated by arrow P1. After this reconfiguration, the magnetic attraction force on the magnetic valve element becomes constant again. Device 101 (Figures 2A-C) includes a stationary permanent magnet 107 that cannot be displaced so that the magnetic attraction force on the magnetic valve element 105 remains constant. In addition to or instead of changing the distance between the magnetic valve element 5;105 and the magnet 7;107, it is also possible to adapt the dimensions of the magnetic valve element 5;105 to obtain a desired pressure threshold for the magnetic valve element 5;105 that is adapted to an individual patient.

[0021] In device 1;201, the drainage channel 3;203 is subdivided into a main channel 3a;203a and a sub-channel 3b;203b within the housing 9;109. Here, the main channel 3a;203a and the sub-channel 3b;203b define the flow path of the drainage channel 3;203 within the housing 9;109. A magnetic valve element 5;205 is provided in at least one of the main channel 3a;203a and the sub-channel 3b;203b. In device 1;201, the magnetic valve element 5;205 is provided in a chamber 25;225 that forms part of the main channel 3a;203a. The sub-channel 3b;203b, which does not have a magnetic valve element, is permanently open. Preferably, the sub-channel 3b;203b has a smaller cross-sectional area (not shown) than the main channel 3a;203a where the magnetic valve element 5;205 is provided. Sub-outlet channels 3b;203b, having a smaller cross-sectional area than the main outlet channels 3a;203a, remain open in both the "low flow" and "high flow" modes of device 1;201. The dimensions of the sub-outlet channels 3b;203b are predetermined to achieve the desired minimum drainage (i.e., to ensure device 1;201 is in "low flow" mode). A magnetic valve element (not shown) may also be included in the sub-outlet channel, which may be configured to remain open longer than the magnetic valve element in the main outlet channel.

[0022] The presence of multiple magnetic valve mechanisms in devices 1;101;201 is possible, though not shown. Multiple magnetic valve mechanisms in multiple drainage channels in an implantable ocular drainage device allow for a wider range of pressure control, for example, by allowing multiple drainage channels to open simultaneously to allow more aqueous humor to drain from the anterior chamber, thereby significantly reducing relatively high intraocular pressure. Furthermore, when multiple self-regulating magnetic valve mechanisms (not shown) are applied in a device, different magnetic attractive forces can be used on the first and second magnetic valve elements so that the first and second magnetic valve elements open and close at different pressure thresholds. Moreover, it is also possible for multiple valves (not shown) in a single implantable ocular drainage device to operate independently in different magnetic field directions. In devices that provide more than two valves, many combinations of valves (open or closed positions) are possible to control the flow in the drainage channels (or channels). In addition, instead of using an uncompartmental drainage channel 103 as shown in Figures 2A-C, it is also possible to subdivide the drainage channel 103 into a main channel and a sub-channel within the housing of the device 101.

[0023] In the device 201 shown in Figures 3A and 3B, the magnetic valve element 205 of the magnetic valve mechanism 204 is a magnetic valve block. This magnetic valve block is fully movable by positioning or activating a magnet 207 on the left or right side of the housing 209. The magnet 207 and its magnetic field move the magnetic valve block from the open position shown in Figure 3A to the closed position shown in Figure 3B, for example, as indicated by arrow P2 in Figure 3B. The open position allows flow through the main channel 203a of the drainage channel 203, and the closed position blocks flow through the main channel 203a of the drainage channel 203.

[0024] In this book, two different valve mechanisms (active type 204; 304; 404 and passive type 4; 104) are disclosed for an implantable eye drainage device. The active type magnetic adjustable devices 201; 301; 401 are composed of a drainage channel 203 including a magnetic microvalve and a housing 209; 409. After implantation of the device 201, the aqueous humor enters the drainage channel 203 and is further subdivided into main 203a and secondary 203b outlet channels. In the main channel 203a, a drive chamber 225 having a microvalve magnetic element 205 in the form of a rectangular valve block is provided. The magnetic valve element 205 and the chamber 225 are not limited to a rectangular shape and can have any shape as long as the main channel 203a can be opened and closed by the magnetic valve element. An external magnet 207 may be used to move this magnetic valve element 205 to the "closed" or "open" position. (i) In the closed position, the device 201 is in a "low flow" mode with maximum hydrodynamic resistance, and (ii) in the open position, the device 201 is in a "high flow" mode with minimum hydrodynamic resistance. In the case of the active device 201, the magnetic valve element 205 should usually be switched and maintained in the closed state ("low flow" mode) to prevent low intraocular pressure in the early postoperative period. And when this initial important period ends and the doctor recognizes a re - rise in pressure, the magnetic valve element 205 is switched to the open position by using the magnet 207 (arranged on the opposite side of the device 201 from Figure 3B) to increase the flow and maintain the IOP at a healthy value. Thus, the flow of fluid through the device 201 can be easily changed by an ophthalmologist by simply moving the external magnet 207 close to the eye according to whether the valve should be opened or closed. The external magnet 207 may be a specially designed instrument capable of generating a specific magnetic field (e.g., one generated by an electromagnet).

[0025] It is also possible to directly provide a microvalve element within at least one drainage channel without using the illustrated chamber.

[0026] In the device 301 shown in FIGS. 4A-C, the magnetic valve element 305 has a pencil-like design, i.e., a body portion 305a and a male end portion 305b. The male end portion 305b is a conical protrusion integrally formed with the body portion 305a. The device 301 includes a female or receiving portion 328 for receiving a part of the magnetic valve element 305. The receiving portion 328 is adapted to receive the male end portion 305b. In the embodiment shown in FIGS. 4A-C, the receiving portion 328 is adapted to receive the male end portion 305b and a part of the body portion 305a near the male end portion 305b. That is, the receiving portion 328 has a first receiving portion 328a and a second receiving portion 328b. The first receiving portion 328a has a shape and size complementary to a part of the body portion 305a near the male end portion 305b. The body portion 305a near the male end portion 305b may be, for example, cylindrical. The second receiving portion 328b has a shape and size complementary to the male end portion 305b. As shown, the receiving portion 328 is provided by a protrusion from the end wall of the chamber 325. Due to the pencil design, the magnetic valve element 305 can be driven relatively reliably and stably by an external magnet 307 between a closed position (FIG. 4c) and an open position (FIG. 4b) or a position between the open and closed positions (not shown).

[0027] FIGS. 5A-D show another embodiment of an implantable eye drainage device 401. The device 401 includes an active valve mechanism 404 (FIG. 5b), i.e., a rotatable magnetic valve element 405 and an external magnet 407.

[0028] The housing 409 is provided with a central notch 425 for receiving the rotatable magnetic valve element 405.

[0029] The magnetic valve element 405 has a mushroom shape, i.e., a head 405a and a stem 405b, as seen in Figures 5A and 5B. The head 405a and stem 405b are cylindrical, with the stem 405b having a smaller diameter than the head 405a. The head 405a and stem 405b are rotatably supported by the housing 409 (in particular, the head 405a is supported on the internal edge 406 of the housing 409). Such a mushroom design facilitates the precise, stable, and reliable rotational movement of the magnetic valve element 405 when using an external magnet 407. The head 405a (larger diameter), as will be discussed later, allows this portion of the element to partially rest on the top of the housing channel, stabilizing the position of the element 405 and blocking undesirable flow from the closed microfluidic housing channel.

[0030] The core of the magnetic valve element 405 is hollow and forms a channel chamber 420 from bottom to top. Fluid can flow between the channel chamber 420 and the internal channel 408 of the magnetic valve element 405. The centerline of the channel chamber 420 (which coincides with the centerline of device 401) coincides with the axis of rotation of the rotatable magnetic valve element 405. Viewed from this axis of rotation, the internal channel 408 extends radially outward from the channel chamber 420. The illustrated internal channel 408 has a wedge shape, where the cross-section of the internal channel 408 increases as it moves away from the channel chamber 420.

[0031] A portion of the housing 409 surrounding the notch 425 for receiving the magnetic valve element 405 includes a plurality of housing channels 414a-c having different dimensions, resulting in different outflow resistances. The housing 409 may further be provided with a disc-shaped cover (not shown) positioned on top of the magnetic valve element 405 and surrounding the housing portion shown in Figures 5A, B. The disc-shaped cover may be provided with a drainage hole providing the outlet side of the housing 409. A drainage channel 403 extends between this drainage hole and one of the outer ends (viewed radially with respect to the axis of rotation) of the housing channels 414a-c.

[0032] When the magnetic valve element 405 rotates in one of the directions indicated by the bidirectional arrow P5, the internal channel 408 may be positioned toward one of the openings of the housing channels 414a-c in the open position (Figure 5A-C) or at least partially open position (not shown), or toward the inner wall 422 of the housing 409 in the closed position (Figure 5D). The primary function of the rotatable magnetic valve element 405 is to open the housing channels 414a-c to enable drainage, or to close them to restrict drainage from the implant. For example, when positioned toward one of the openings of the housing channels 414a-c, as shown in Figure 5A-C, the fluid flowing through this housing channel flows through the internal channel 408 and channel chamber 420 toward the top outlet and out of the implantable ophthalmic drainage device 401. A secondary function of the magnetic valve element 405 may be to select which of the housing channels 414a-c should be opened. For example, the flow between internal channel 408 and channel 414a (the dotted line in Figure 5C indicates internal channel 408) provides high drainage, the flow between internal channel 408 (see Figure 5C) and channel 414b provides moderate drainage, and / or the flow between internal channel 408 and channel 414c (the dotted line in Figure 5C indicates internal channel 408) provides low drainage. If internal channel 408 is positioned toward the inner wall 422 of housing 409 (Figure 5D), no drainage is provided as described above.

[0033] The outer ends of the housing channels 414a-c may be connected by tubing to a ring (not shown) surrounding the device 401. Here, aqueous humor from the anterior chamber is drained through the tubing into the ring and device 401.

[0034] In the illustrated embodiment of the implantable ocular drainage device 401, the device 401 comprises three housing channels 414a-c, but it is also possible to provide more or fewer housing channels. It is also possible to provide a single housing channel. In this case, flow can be controlled by the alignment of the internal channel 408 of the rotatable magnetic valve element 405 with respect to the opening of the single housing channel. In such an embodiment, a “full” alignment between the internal channel 408 and the opening of the single housing channel means maximum flow between the internal channel and the single housing channel, and a rotation to a position between a “half” alignment or a “full” alignment means reduced flow relative to the maximum flow between the internal channel and the single housing channel. Also, if the internal channel 408 is positioned toward the inner wall 422 of the housing 409, no drainage / flow is provided as described above.

Claims

1. It comprises at least one drainage channel and at least one magnetic control mechanism, The at least one magnetic control mechanism is a magnetic valve mechanism configured to restrict flow in the at least one drainage channel, The magnetic valve mechanism comprises a rotatable magnetic valve element provided for at least one drainage channel, and an external magnet located outside the at least one drainage channel, for providing a magnetic attraction to the rotatable magnetic valve element in order to control the flow in the drainage channel by rotating the rotatable magnetic valve element in one of two rotational directions. The rotatable magnetic valve element has a hollow core that forms a channel chamber from bottom to top, The channel chamber is capable of fluid flowing between it and the internal channel of the rotatable magnetic valve element. The internal channel extends radially outward from the channel chamber. An implantable ocular drainage device for controlling intraocular pressure, characterized by the following features.

2. The device according to claim 1, wherein the external magnet is adapted to be displaced between predetermined positions relative to the magnetic valve element in response to fluctuations in the magnetic attraction on the magnetic valve element.

3. The implantable ocular drainage device comprises a housing, The at least one drainage channel extends between the inlet side and the outlet side of the housing, The device according to claim 1.

4. The device according to claim 3, wherein, when the magnetic valve element rotates in one of the two rotational directions, the internal channel of the magnetic valve element rotates so as to be positioned toward an opening of one of the plurality of housing channels of the housing in an open or at least partially open position, or toward the inner wall of the housing in a closed position.

5. The device according to claim 3, wherein when the magnetic valve element rotates in one of the two rotational directions, the internal channel of the magnetic valve element can be rotated so as to be positioned toward the opening of a single housing channel of the housing in an open or at least partially open position, or toward the inner wall of the housing in a closed position.

6. The device according to claim 3, wherein the magnetic valve mechanism is provided within the housing.

7. The device according to claim 3, wherein the housing is provided with a central notch for receiving the rotatable magnetic valve element.

8. The magnetic valve element has a mushroom shape with a head and a stem, The head and stem are cylindrical. The aforementioned stem portion has a smaller diameter than the aforementioned head portion. The head and the stem are rotatably supported by the housing. The device according to claim 7.

9. The device according to claim 1, wherein the at least one drainage channel is connectable to or connected to a drainage tube that collects aqueous humor from the anterior chamber during use.

10. Within the housing, the at least one drainage channel is subdivided into a main channel and a sub-channel. The main channel and the sub-channel define the flow path of the at least one drainage channel within the housing. The device according to claim 3.

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