Adjustable Flow Glaucoma Shunt and Related Systems and Methods

Abstract

The present technology is directed to adjustable shunts for treating glaucoma. In particular, some embodiments provide shunts having multiple individually actuatable flow control elements that can control the flow of fluid through associated ports and / or flow lumens. For example, each individually actuatable flow control element can be actuated to block and / or unblock a corresponding port and / or flow lumen. Thus, the shunts described herein can be manipulated into various configurations that provide different drainage rates based on whether a port and / or flow lumen is blocked or unblocked, thus providing a titratable glaucoma treatment for draining aqueous from the anterior chamber of the eye.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 965,117, filed on January 23, 2020, the content of which is hereby incorporated by reference in its entirety.

[0002] The present technology generally relates to implantable medical devices, particularly intraocular shunt systems, and related methods for selectively controlling the flow of fluid between different parts of a patient's eye.

Background Art

[0003] Glaucoma is a degenerative eye condition involving damage to the optic nerve that can cause progressive and irreversible vision loss. Glaucoma is often associated with elevated intraocular pressure, an increase in the pressure within the eye, and can result from an increase in the production of aqueous humor (the "water") within the eye and / or a decrease in the rate of outflow of the water from the eye into the bloodstream. The water is produced within the ciliary body, which is at the boundary between the posterior and anterior chambers of the eye. This flows into the anterior chamber and ultimately into the venous blood vessels of the eye. Glaucoma is typically caused by a disorder within the mechanism that transports water from the eye into the bloodstream.

Summary of the Invention

Means for Solving the Problems

[0004] The present technology is directed to systems, devices, and methods for treating glaucoma. In particular, some embodiments provide a shunt having a plurality of individually actuatable flow control elements capable of controlling the flow of fluid through associated ports and / or channels within the shunt. For example, each individually actuatable flow control element can be actuated to substantially block and / or substantially unblock a corresponding port and / or channel, thereby suppressing or permitting flow through the port and / or channel. Accordingly, the shunts described herein can be operated in various configurations to provide different drainage rates based on whether a port and / or channel is blocked or unblocked, and thus provide a titratable glaucoma treatment for draining aqueous humor from the anterior chamber of the eye. In an embodiment, after the shunt is implanted in the eye, the flow control elements can be adjusted non-invasively to allow for post-implantation adjustment.

[0005] In many of the embodiments described herein, the shunt system includes ports and / or drainage channels configured to provide different treatment levels to other ports and / or drainage channels of the system. For example, a first port and / or channel can be associated with a first drainage rate and / or a first fluid resistance, a second port and / or channel can be associated with a second drainage rate and / or a second fluid resistance, and a third port and / or channel can be associated with a third drainage rate and / or a third fluid resistance. As will be explained below, this can be achieved by having ports and / or drainage channels with different dimensions (e.g., diameter, cross-sectional area, length, etc.). In some embodiments, the ports and channels are arranged as fluid resistances parallel to the primary drainage lumen. In other embodiments, the inflow ports and channels are arranged as series fluid resistances with respect to the primary drainage lumen.

[0006] In embodiments where the inlet port and channel are arranged as parallel fluid resistances to the primary drain lumen, each individual port can be associated with a distinct different relative resistance and / or flow. For example, the first port can allow for a flow of 1X, the second port can allow for a flow of 2X, and the third port can allow for a flow of 3X. Further, since the ports are arranged as parallel fluid resistances, any combination of ports can be opened (e.g., unblocked) or closed (e.g., blocked, interfered with, etc.) to provide additional individual relative resistances and / or drain rates that are different from the individual relative resistances and flows associated with each individual port. In the foregoing example, both the second and third ports can be opened to provide a flow of 5X. In some embodiments, the relative dimensions of the ports and / or channels can be selected to specifically provide a maximum number of individual treatment levels. For example, in some embodiments, the ratio between a first drain rate, a second drain rate, and a third drain rate can be about 1:2:4. Similarly, the ratio between a first resistance, a second resistance, and a third resistance can be about 4:2:1. Without being bound by theory, it is expected that this will increase the number of individual treatment levels that the system can provide, and similarly, it is expected that this will enable a medical institution to specifically match the treatment level to the needs of a particular patient.

[0007] In embodiments where the inlet port and channel are arranged as series fluid resistances to the main drain lumen, each individual inlet port can still be associated with an individual resistance and / or drain rate. However, unlike embodiments where the ports are arranged as parallel fluid resistances, the system cannot be operated to achieve multiple combined resistances and / or flow rates that are different from the individual resistances and / or drain rates provided for each individual port. The present invention provides, for example, the following items. (Item 1) A system for draining a fluid, a drainage element having a first end region positionable within a first body region and a second end region positionable within a second body region, the first end region including a first port, a second port, and a third port, the drainage element; a flow control mechanism for controlling the flow of fluid through the drainage element, a first flow control element movable between a first open position that allows fluid to flow into the drainage element through the first port and a first closed position that substantially prevents fluid from flowing into the drainage element through the first port; a second flow control element movable between a second open position that allows fluid to flow into the drainage element through the second port and a second closed position that substantially prevents fluid from flowing into the drainage element through the second port; a third flow control element movable between a third open position that allows fluid to flow into the drainage element through the third port and a third closed position that substantially prevents fluid from flowing into the drainage element through the third port, wherein the first flow control element, the second flow control element, and the third flow control element are each independently movable between their respective open and closed positions, the flow control mechanism; a system comprising. (Item 2) When the first flow control element is in the first open position, the second flow control element is in the second closed position, and the third flow control element is in the third closed position, the system is configured to provide a first relative resistance to fluid flow, When the second flow control element is in the second open position, the first flow control element is in the first closed position, and the third flow control element is in the third closed position, the system is configured to provide a second relative resistance, When the third flow control element is in the third open position, the first flow control element is in the first closed position, and the second flow control element is in the second closed position, the system is configured to provide a third relative resistance, the system according to Item 1. (Item 3) The system according to item 2, wherein the second relative resistance is less than the first relative resistance, and the third relative resistance is less than the first relative resistance. (Item 4) The system according to item 3, wherein the ratio among the first relative resistance, the second relative resistance, and the third relative resistance is about 4:2:1. (Item 5) The system according to item 3, wherein the ratio among the first relative resistance, the second relative resistance, and the third relative resistance is about 3:2:1. (Item 6) The system according to item 2, wherein the ratio among the first relative resistance, the second relative resistance, and the third relative resistance is about 1:1:1. (Item 7) When the first flow control element is within the first open position, the second flow control element is within the second closed position, and the third flow control element is within the third closed position, the system is configured to provide a first relative drainage rate. When the second flow control element is within the second open position, the first flow control element is within the first closed position, and the third flow control element is within the third closed position, the system is configured to provide a second relative drainage rate. The system according to item 1, wherein when the third flow control element is within the third open position, the first flow control element is within the first closed position, and the second flow control element is within the second closed position, the system is configured to provide a third relative drainage rate. (Item 8) The system according to item 7, wherein the second relative drainage rate is greater than the first relative drainage rate, and the third relative drainage rate is greater than the second relative drainage rate. (Item 9) The system according to item 8, wherein the ratio among the first relative drainage rate, the second relative drainage rate, and the third relative drainage rate is about 1:2:4. (Item 10) The system according to item 8, wherein the ratio among the first relative drainage rate, the second relative drainage rate, and the third relative drainage rate is about 1:2:3. (Item 11) The system according to item 7, wherein the ratio among the first relative drainage rate, the second relative drainage rate, and the third relative drainage rate is about 1:1:1. (Item 12) The system according to item 1, wherein the drainage element has a first channel fluidly coupled to the first port, a second channel fluidly coupled to the second port, and a third channel fluidly coupled to the third port. (Item 13) The system according to item 12, wherein the first channel is configured to provide a relative resistance greater than that of the second channel, and the second channel is configured to provide a relative resistance greater than that of the third channel. (Item 14) The system according to item 13, wherein the first channel has a first cross-sectional area, the second channel has a second cross-sectional area greater than the first cross-sectional area, and the third channel has a third cross-sectional area greater than the second cross-sectional area. (Item 15) The system according to item 1, wherein the first port has a first area, the second port has a second area greater than the first area, and the third port has a third area greater than the second area. (Item 16) The system according to item 1, wherein the first port includes a single opening, the second port includes two openings, and the third port includes three or more openings. (Item 17) The system according to item 1, wherein the first port is a first inlet port, the second port is a second inlet port, and the third port is a third inlet port. (Item 18) The system according to item 1, wherein the first body region is the anterior chamber and the fluid is water. (Item 19) A system for draining fluid, a drainage element having a first end region positionable within a first body region and a second end region positionable within a second body region, the first end region including a first inlet port and a second inlet port, wherein the system is configured to provide a first relative drainage rate through the drainage element when the first inlet port is unblocked and the second inlet port is blocked, and a drainage element, wherein when the second inlet port is unblocked and the first inlet port is blocked, the system is configured to provide a second relative drainage rate through the drainage element that is greater than the first relative drainage rate, a flow control mechanism, a first flow control element configured to selectively control the flow of fluid through the first inlet port, and a second flow control element configured to selectively control the flow of fluid through the second inlet port, a flow control mechanism, wherein the first flow control element and the second flow control element are operable independently; a system comprising the same. (Item 20) The system according to item 19, wherein the ratio between the first relative drainage rate and the second relative drainage rate is 1:2. (Item 21) The system according to item 20, wherein when both the first inlet port and the second inlet port are unblocked, the system is configured to provide a third relative drainage rate through the drainage element that is greater than the first relative drainage rate and the second relative drainage rate. (Item 22) The system according to item 21, wherein the ratio between the first, second, and third relative drainage rates is 1:2:3. (Item 23) The system according to item 19, wherein the first inlet port includes a single opening, and the second inlet port includes a plurality of openings. (Item 24) The system according to item 19, wherein the first inlet port has a first area, and the second inlet port has a second area that is larger than the first area. (Item 25) The system according to item 19, wherein the drainage element includes (i) a first lumen extending between the first inlet port and the second end region, and (ii) a second lumen extending between the second inlet port and the second end region, and the first lumen is configured to provide a resistance to the flow of a fluid different from that of the second lumen. (Item 26) The system according to item 19, wherein the drainage element further includes a third inlet port, and when the third inlet port is unblocked and the first and second inlet ports are blocked, the system is configured to provide a third relative drainage rate through the drainage element. (Item 27) The system according to item 26, wherein the ratio between the first relative drainage rate, the second relative drainage rate, and the third relative drainage rate is approximately 1:2:3. (Item 28) The system according to item 26, wherein the ratio between the first relative drainage rate, the second relative drainage rate, and the third relative drainage rate is approximately 1:2:4. (Item 29) The drainage element further comprises a fourth inflow port, and when the fourth inflow port is unblocked and the first, second, and third inflow ports are blocked, the system is configured to provide a fourth relative drainage rate that passes through the drainage rate, and the ratio of the first, second, third, and fourth relative drainage rates is about 1:2:4:8. The system according to item 25. (Item 30) The system according to item 19, wherein the first body region is the anterior chamber of the eye and the fluid is water. (Item 31) The system according to item 19, wherein the drainage element includes a plate extending from a first end portion, and the plate includes the first and second inflow ports. (Item 32) An adjustable shunt, A drainage element having a first end portion positionable within the anterior chamber of a patient's eye and a second end portion positionable within a target outflow location of the patient, The first end portion includes at least three inflow ports, the first inflow port being configured to provide a first drainage rate when only the first inflow port is open, the second inflow port being configured to provide a second drainage rate greater than the first drainage rate when only the second inflow port is open, and the third inflow port being configured to provide a third drainage rate greater than the second drainage rate when only the third inflow port is open. The second end portion includes at least one outflow port, A drainage element having a lumen extending through the drainage element from the first end portion to the second end portion to fluidly connect the at least three inflow ports and the at least one outflow port, A flow control mechanism having at least three individually operable flow control elements, wherein the first flow control element is selectively operable to block and unblock the first inflow port, the second flow control element is selectively operable to block and unblock the second inflow port, and the third flow control element is selectively operable to block and unblock the third inflow port. An adjustable shunt comprising a flow control mechanism. (Item 33) The first drainage rate, the second drainage rate, and the third drainage rate are predetermined relative drainage rates, the first drainage rate is about X, the second drainage rate is about 2X, and the third drainage rate is about 3X, the adjustable shunt according to item 32. (Item 34) The first drainage rate, the second drainage rate, and the third drainage rate are predetermined relative drainage rates, the first drainage rate is about X, the second drainage rate is about 2X, and the third drainage rate is about 4X, the adjustable shunt according to item 32. (Item 35) When two or more inflow ports are open, the shunt is configured to provide a fourth relative drainage rate different from the first drainage rate, the second drainage rate, and the third drainage rate, the adjustable shunt according to item 34. (Item 36) The shunt is when only the first inflow port and the second inflow port are open, a fourth drainage rate of about 3X, when only the first inflow port and the third inflow port are open, a fifth drainage rate of about 5X, when only the second inflow port and the third inflow port are open, a sixth drainage rate of about 6X, and when the first inflow port, the second inflow port, and the third inflow port are open, configured to provide an additional predetermined relative drainage rate including a seventh drainage rate of about 7X, the adjustable shunt according to item 34. (Item 37) The flow control element is selectively operable to achieve any of the predetermined relative drainage rates, the adjustable shunt according to item 36. (Item 38) A method for treating glaucoma, discharging water from the anterior chamber of the eye to a target outflow location using an adjustable shunt, the adjustable shunt comprising a first inflow port fluidly coupled to the interior of the shunt, a second inflow port fluidly coupled to the interior of the shunt, a first flow control element movable between a first open position that allows fluid to flow into the shunt through the first inflow port and a first closed position that substantially prevents fluid from flowing into the shunt through the first inflow port, A second flow control element movable between a second open position that enables fluid to flow into the shunt through the first inlet port and a second closed position that substantially prevents fluid from flowing into the shunt through the first inlet port, and draining. A method comprising selectively adjusting the drainage rate of the water by actuating the first flow control element and / or the second flow control element between their respective open and closed positions. (Item 39) The method according to item 38, wherein the first inlet port provides a first drainage rate when only the first inlet port is unblocked, and the second inlet port provides a second drainage rate greater than the first drainage rate when only the second inlet port is unblocked. (Item 40) The method according to item 38, wherein actuating at least one of the individually actuable flow control elements includes applying energy to at least one of the individually actuable flow control elements. (Item 41) The method according to item 40, wherein the energy is non-invasive energy.

Brief Description of the Drawings

[0008] Many aspects of the present technology can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale. Instead, emphasis is placed on clearly illustrating the principles of the present technology. Further, components may be shown as transparent in certain figures only for clarity of explanation, and this does not indicate that the illustrated components are necessarily transparent. Also, components may be shown schematically.

[0009]

Figure 1A

Figure 1B

Figure 2A

Figure 2B

Figure 2C

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 4C

Figure 5A

Figure 5B

Figure 5C

Figure 6

Best Mode for Carrying Out the Invention

[0010] The technical terms used in the description presented below are intended to be interpreted in the broadest reasonable way, even when used in conjunction with a detailed description of specific particular embodiments of the present technology. Certain terms may even be emphasized below, however, any technical terms intended to be interpreted in any restricted way are clearly and specifically defined as such in this "Best Mode for Carrying Out the Invention" section. Additionally, the present technology can include other embodiments that are within the scope of the examples but are not described in detail with respect to FIGS. 1A - 6.

[0011] When referring to "one embodiment" or "an embodiment" in this specification, it means that the specific features, structures, or characteristics described in relation to that embodiment are included in at least one embodiment of the present technology. Thus, when the phrases "in one embodiment" or "in an embodiment" appear in various places throughout this specification, they do not necessarily all refer to the same embodiment. Furthermore, the specific features or characteristics can be combined in any suitable way in one or more embodiments.

[0012] Throughout this specification, when referring to relative terms such as "generally", "approximately", and "about", this specification is used to mean plus or minus 10% of the recited value. References to the term "resistance" throughout this specification refer to fluid resistance, unless the context clearly dictates otherwise. The terms "drainage rate" and "flow" are used interchangeably to describe the movement of fluid through a structure.

[0013] Certain embodiments of this specification are described with respect to shunting fluid from the anterior chamber of the eye, but those skilled in the art will understand that this technology can be readily adapted to shunt fluid from other parts of the eye and / or between other parts of the eye, and more generally, from a first body region and a second body region, and / or between a first body region and a second body region. Further, certain embodiments of this specification are described in the context of treating glaucoma, but any embodiment of this specification, including what is referred to as a "glaucoma shunt" or "glaucoma device", can nevertheless be used and / or modified to treat other diseases or conditions, including other diseases or conditions of the eye or other body regions. For example, the systems described herein can be used to treat diseases characterized by increased pressure and / or fluid accumulation, including but not limited to heart failure (e.g., heart failure maintaining ejection fraction, heart failure with reduced ejection fraction, etc.), lung failure, kidney failure, hydrocephalus, etc. Further, although generally described with respect to shunting water, the systems described herein can equally be applied to shunt other fluids such as blood or cerebrospinal fluid between a first body region and a second body region.

[0014] The headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed technology.

[0015] A. Intraocular shunt for glaucoma treatment Glaucoma refers to a group of eye diseases associated with damage to the optic nerve, which ultimately causes vision loss and blindness. As described above, glaucoma is a degenerative eye condition characterized by increased intraocular pressure resulting from an increase in the production of aqueous humor within the eye and / or a decrease in the rate of outflow of aqueous humor from the eye into the bloodstream. The increased pressure leads to damage to the optic nerve over time. Unfortunately, patients often do not experience symptoms of increased intraocular pressure until glaucoma develops. Therefore, patients typically must be closely monitored for increased pressure, even when asymptomatic. Since monitoring continues throughout the course of the disease, clinicians can intervene early to halt the progression of the disease. To monitor pressure, patients need to visit a clinic regularly, which is expensive, time-consuming, and inconvenient. The early stages of glaucoma are typically treated with medications (e.g., eye drops) and / or laser treatment. However, when medications / laser treatment is insufficient, a surgical approach can be used. Surgical or minimally invasive approaches attempt to increase the outflow of aqueous humor from the anterior chamber into the bloodstream, mainly by either creating an alternative fluid pathway or enhancing the natural pathway for aqueous humor outflow.

[0016] Figures 1A and 1B illustrate suitable locations within the human eye E where a shunt according to embodiments of the present technology can be implanted. More specifically, FIG. 1A is a simplified front view of the eye E with the shunt 100 implanted, and FIG. 1B is an isometric view of the eye E and the shunt 100 of FIG. 1A. Referring first to FIG. 1A, the eye E includes several muscles for controlling its movement, including the superior rectus muscle SR, the inferior rectus muscle IR, the lateral rectus muscle LR, the medial rectus muscle MR, the superior oblique muscle SO, and the inferior oblique muscle IO. The eye E also includes the iris, the pupil, and the limbus.

[0017] Referring to both FIGS. 1A and 1B, shunt 100 can have a drainage element 105 (e.g., a drainage tube) positioned such that the inflow portion 101 is positioned within the anterior chamber of the eye E and the outflow portion 102 is positioned at a different location within the eye E, such as a bleb space. The shunt 100 can be implanted in various orientations. For example, when implanted, the drainage element 105 can extend upward, downward, inward, and / or outward from the anterior chamber. Depending on the design of the shunt 100, the outflow portion 102 can be placed at several different suitable outflow locations (e.g., between the choroid and the sclera, between the conjunctiva and the sclera, etc.).

[0018] Outflow resistance can change over time, for example, when the outflow location undergoes the healing process after surgical implantation of a shunt (e.g., shunt 100, etc.), or due to various reasons such as further obstruction within the drainage network that passes from the anterior chamber through the trabecular meshwork, Schlemm's canal, collector channels, and ultimately into the veins and the body's circulatory system. Thus, a clinician may desire to modify the shunt after implantation to either increase or decrease the outflow resistance in response to such changes or other clinical reasons. For example, in many procedures, the shunt is modified at the time of implantation to temporarily increase the outflow resistance. After a period of time determined to be sufficient to allow tissue healing and stabilization of the outflow resistance, the modification to the shunt is reversed, thereby decreasing the outflow resistance. In another example, a clinician may implant the shunt and then, after monitoring the intraocular pressure, determine whether a modification to the drainage rate through the shunt is desired. Such modifications can be invasive, time-consuming, and / or expensive for the patient. However, failure to follow such procedures increases the likelihood of creating hypotony (excessively low intraocular pressure), which can lead to further complications, including damage to the optic nerve. In contrast, an intraocular shunt system configured in accordance with embodiments of the present technology allows a clinician to selectively adjust the flow of fluid through the shunt after implantation without additional invasive surgical procedures.

[0019] The shunts described herein are implanted with a first drainage rate and can then be remotely adjusted to achieve a second, different drainage rate. The adjustment can be based on the needs of the individual patient. For example, the shunt can be implanted at a first, lower flow rate and then adjusted to a second, higher flow rate if clinically necessary. The shunts described herein can be delivered using either ab interno or ab externo implantation techniques and can be delivered via a needle. The needle can have various shapes and configurations to accommodate the various shapes of the shunts described herein. Details of the implantation technique, implantation device, and bleb formation are described in detail in International Patent Application No. PCT / US20 / 41152, filed July 8, 2020, entitled "MINIMALLY INVASIVE BLEB FORMATION DEVICES AND METHODS FOR USING SUCH DEVICES," the disclosure of which is incorporated herein by reference for all purposes.

[0020] In many of the embodiments described herein, the flow control assembly is configured to introduce features that selectively impede or attenuate the flow of fluid through the shunt during operation. In this way, the flow control assembly can change the flow resistance through the shunt in a stepwise or continuous manner to selectively regulate pressure and / or flow. Thus, a flow control assembly configured in accordance with the present technology can adjust the level of interference or compression between several different locations and accommodate many variables (e.g., IOP, aqueous production rate, native aqueous outflow resistance, and / or native aqueous outflow rate) to accurately regulate the flow rate through the shunt.

[0021] The disclosed flow control assembly can operate using energy. This feature enables such a device to be implanted within a patient and modified / adjusted over time without performing additional invasive surgeries or procedures on the patient. Further, since the devices disclosed herein can be actuated via energy from an external energy source (e.g., a laser), such devices do not require any additional power to maintain a desired orientation or position. Rather, the actuators / fluid resistors disclosed herein can maintain a desired position / orientation without power. This can significantly increase the useful life of such devices and enable such devices to remain effective long after an initial implantation procedure.

[0022] B. Adjustable Glaucoma Shunt Figures 2A-2C illustrate an adjustable shunt 200 (the "shunt 200") configured in accordance with an embodiment of the present technology. Referring first to Figure 2A, the shunt 200 includes a drainage element or tube 202 having a first end portion 204 and a second end portion 206 opposite the first end portion 204. The drainage element 202 can have a plurality of inflow ports or openings (referred to herein as port 208 shown in Figure 2B) at or adjacent to the first end portion 204 and an outflow opening 207 at or adjacent to the second end portion 206. The port 208 can be arranged and / or configured to provide something equivalent to a set of parallel fluid resistors accessing a primary lumen of the device. The primary lumen can extend through the drainage element 202 to fluidly communicate the plurality of ports 208 and the outflow opening 207. Thus, the shunt 200 can also be referred to as a parallel resistor.

[0023] In some embodiments, the drainage element 202 can be relatively flat such that its height is less than its width (e.g., the drainage element 202 has an elliptical, rectangular, or "D-shaped" cross-sectional shape). In such embodiments, the drainage element 202 can have an outer diameter (e.g., height) of about 1000 micrometers (μm) or less, about 400 μm or less, or about 300 μm or less. The drainage element 202 can have an outer diameter value that is between any of the aforementioned outer diameter values. In some embodiments, the drainage element can have an inner diameter of about 800 μm or less, about 300 μm or less, or about 200 μm or less. The drainage element 202 can have an inner diameter value that is between any of the aforementioned inner diameter values. In some embodiments, the drainage element 202 can have a length of about 2 mm, about 2.5 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 15 mm, or about 20 mm. The drainage element 202 can have a length that is between any of the aforementioned length values. In other embodiments, the drainage element 202 can be substantially cylindrical. Without wishing to be bound by theory, having a relatively flat profile is expected to advantageously reduce interference with natural tissue while enhancing the stability of the shunt 200.

[0024] The shunt 200 can include a flow control mechanism 210 positioned at a first end portion 204 of the drainage element 202. When the shunt 200 is implanted into the eye, the first end portion 204 can be present within the anterior chamber, and the second end portion 206 can be present within a desired outflow location (e.g., a bleb space as described in International Patent Application No. PCT / US20 / 41152, which is hereby incorporated by reference in its entirety). In such an embodiment, the flow control mechanism 210 is positioned within the anterior chamber. In other embodiments, the first end portion 204 can be present within the desired outflow location and the second end portion 206 can be present within the anterior chamber (e.g., fluid flows from the outflow opening 207 to the port 208). In such an embodiment, the flow control mechanism 210 is positioned outside the anterior chamber (e.g., within the bleb space). Regardless of the orientation of the shunt 200, the shunt 200 is configured to drain water from the anterior chamber when the shunt 200 is implanted into the eye. The shunt 200 can optionally have additional features that help to fix the shunt 200 in a predetermined position when implanted into the eye. For example, the shunt 200 can include an arm, an anchor, a plate, or other suitable features (not shown) that can fix the shunt 200 to natural tissue. The shunt 200 can also include an outer membrane or cover (e.g., a transparent and / or biocompatible membrane) that surrounds some or all of the shunt 200.

[0025] Referring now to FIGS. 2B and 2C, the flow control mechanism 210 includes a plurality of flow control elements 211a-d disposed along the length of the drainage element 202. The individual flow control elements 211a-d can interface with corresponding individual ports 208, and each flow control element 211a-d can be individually actuable. Thus, as described below, the shunt 200 can be operated in any number of configurations where all of the ports 208 (FIG. 2C), some of the ports 208 are blocked or substantially blocked, or none of the ports 208 are blocked (FIG. 2B). The more ports 208 that are unblocked or otherwise accessible, the more fluid can be drained through the drainage element 202. As will be described in detail with respect to FIGS. 3A and 3B, the ports 208 can have the same or different dimensions. In some embodiments, the ports 208 are generally regularly spaced (e.g., spaced approximately 1 mm apart). In some embodiments, the ports 208 are spaced such that the distance between adjacent ports 208 varies. For example, at least two adjacent ports 208 can have a spacing distance different from the spacing distances between the other ports 208 of the plurality of ports 208.

[0026] Each of the flow control elements 211a-d includes a pair of anchors 212 spaced along the length of the drain element 202 (e.g., the first flow control element 211a includes a first anchor 212a and a second anchor 212b). In some embodiments, adjacent flow control elements 211a-d can share an anchor. For example, the second anchor 212b supports both the first flow control element 211a and the second flow control element 211b. The anchors 212 are fixed to the drain element 202 such that at least one of the ports 208 is generally positioned between each pair of anchors. The anchors 212 can be fixed to the drain element 202 or other structure so that the flow control elements 211a-d do not move when they are actuated. For example, the anchors 212 can be wrapped around the circumference of the drain element 202 and fixed thereto via a friction fit or other suitable attachment mechanism. In other embodiments, the anchors 212 do not wrap around the entire circumference of the drain element, but still fix the flow control mechanism 210 to the drain element 202 (e.g., via welding, adhesion, or other suitable bonding techniques).

[0027] Each individual flow control element 211a - d further includes a first actuation element (e.g., flow control element 211a includes a first actuation element 214a) that extends between a movable gate element (e.g., flow control element 211a includes a gate element 216a, flow control element 211b includes a gate element 216b, etc., collectively referred to herein as gate element 216) and a first anchor (e.g., first anchor 212a), and a second actuation element (e.g., flow control element 211b includes a second actuation element 214b) that extends between the gate element 216 corresponding to a second anchor (e.g., second anchor 212b). Each gate element 216a - d is configured to interface connect with a corresponding port 208 (e.g., at least partially block or otherwise form a substantial or complete fluid seal). The actuation element can be selectively actuated to selectively move the corresponding gate element 216 between one or more positions that block (or partially block) the corresponding port 208 and one or more positions that unblock (or partially unblock) the corresponding port 208.For example, (a) the gate element 216a of the first flow control element 211a can move between a first open position that allows fluid to flow into the drain element 202 through the corresponding port 208 and a first closed position that substantially prevents fluid from flowing into the drain element 202 through the corresponding port 208, (b) the gate element 216b of the second flow control element 211b can move between a second open position that allows fluid to flow into the drain element 202 through the corresponding port 208 and a second closed position that substantially prevents fluid from flowing into the drain element 202 through the corresponding port 208, (c) the gate element 216c of the third flow control element 211c can move between a third open position that allows fluid to flow into the drain element 202 through the corresponding port 208 and a third closed position that substantially prevents fluid from flowing into the drain element 202 through the corresponding port 208, and (d) the gate element 216d of the fourth flow control element 211d can move between a fourth open position that allows fluid to flow into the drain element 202 through the corresponding port 208 and a fourth closed position that substantially prevents fluid from flowing into the drain element 202 through the corresponding port 208. When in the closed and open positions, the inlet port is described as being "blocked" and "unblocked", but the gate element can also be described as not interfering with and / or not imparting a first fluid resistance through the outlet when in the open position, and interfering with and / or imparting a second fluid resistance greater than the first fluid resistance when in the closed position.

[0028] The gate element 216 can be moved by actuating the actuating element 214. For example, when the second actuating element 214a is actuated, the gate element 216a can be moved in a first direction, and when the first actuating element 114b is actuated, the gate element 216a can be moved in a second direction substantially opposite to the first direction. To facilitate the aforementioned movement of the gate element 216, the actuating element can be at least partially composed of a shape memory material (e.g., shape memory alloy) or other suitable material configured to change shape upon application of energy. For example, in some embodiments, the actuating element is composed of nitinol. In such embodiments, the actuating element (and / or a region thereof) can be transitionable between at least a first material phase or state (e.g., martensite state, R-phase, composite state between martensite and R-phase, etc.) and a second material phase or state (e.g., austenite state, R-phase state, composite state between austenite and R-phase, etc.). In the first material state, the actuating element or a selected region thereof can be deformable (e.g., plastic, malleable, compressible, expandable, etc.). In the second material state, the actuating element or a selected region thereof can have a preference for a particular preferred geometry (e.g., original geometry, manufactured or fabricated geometry, heat-set geometry, etc.). As described below, the actuating element can be transitioned individually and / or selectively between the first and second material states by applying energy (e.g., heat, light, etc.) to the actuating element to heat the actuating element above a transition temperature (e.g., phase transition temperature). When the actuating element is deformed relative to its preferred geometry, the transition from the first material state to the second material state can induce a dimensional change within the actuating element. In some embodiments, the dimensional change is an expansion. In some embodiments, the dimensional change is a contraction (e.g., compression). In some embodiments, the energy is applied from an energy source (e.g., a laser) positioned external to the eye, whereby the user can non-invasively adjust the shunt.

[0029] The flow control element 211a (e.g., the first actuating element 214a or the second actuating element 214b) can be actuated to move (e.g., translate) the gate element 216a along the axial length of the drain element 202 between the first anchor 212a and the second anchor 212b. This movement of the gate element 216a can block (e.g., partially or fully block) and / or unblock (e.g., partially or fully unblock) the associated port 208. For example, in an embodiment where the first actuating element 214a is compressed relative to its preferred geometry, heating the first actuating element 214a above its transition temperature can cause the first actuating element 214a to expand and / or cure (thereby expanding its length). Since the first anchor 212a and the second anchor 212b are fixed in place (e.g., they do not move relative to the drain element 202), the first actuating element 214a presses the gate element 216a away from the first anchor 212a as the gate element 216a expands (and moves towards the second anchor 212b). As illustrated in FIG. 2B, this can unblock the port 208 that was previously covered by the gate element 216a, thereby allowing fluid to flow into (or out of) the port 208. Similarly, heating the second actuating element 214b causes the second actuating element 214b to expand, which presses the gate element 216a away from the second anchor 212b and back towards the first anchor 212a. As illustrated in FIG. 2C, this causes the gate element 216a to block the port 208, thereby preventing fluid from flowing into (or out of) the port 208. Thus, the first actuating element 214a and / or the second actuating element 214b can be selectively targeted to block and / or unblock the port 208. In some embodiments, the first actuating element 214a and / or the second actuating element 214b can be actuated to partially block or partially unblock the port 208, rather than fully blocking and / or fully unblocking the port 208.

[0030] In some embodiments, the actuating elements are configured to retain or substantially retain their shape following the application of energy. For example, when energy is applied to the first actuating element 214a to transition the first flow control element 211a from the configuration shown in FIG. 2C to the configuration shown in FIG. 2B, the first flow control element 211a can maintain the configuration shown in FIG. 2B until additional energy is applied to the first flow control element 211a. Thus, when the first flow control element 211a is actuated to unblock the corresponding port 208, the corresponding port 208 remains unblocked until additional energy is applied to the first flow control element 211a (e.g., by application of energy to the second actuating element 214b). In other embodiments, the actuating elements may exhibit a (partial) reaction effect such that when the application of energy ends, the energized actuating element reacts towards its original shape.

[0031] The foregoing description is directed to the first flow control element 211a, but the components associated with the flow control elements 211b-d can be actuated in a similar manner. Further details regarding the operation of the shape memory actuators for glaucoma shunts are described in U.S. Patent Application Publication No. 2020 / 0229982, as well as International Patent Applications PCT / US20 / 55144 and PCT / US20 / 55141, the disclosures of which are hereby incorporated by reference in their entirety for all purposes.

[0032] The shunt 200 can be set such that at body temperature, all or some of the ports 208 are blocked by the corresponding gate elements 216, or none of the ports 208 are blocked by the corresponding gate elements 216. Thus, in some embodiments, the shunt 200 can have a basic configuration in which all or some of the ports 208 are blocked by the corresponding gate elements 216, or none of the ports 208 are blocked by the corresponding gate elements 216.

[0033] The drainage of water through the shunt 200 can be selectively controlled by selectively blocking and / or unblocking the ports 208 using the flow control elements 211a-d. For example, to provide a first level of therapy having a first drainage rate and a first flow resistance, one of the ports 208 can be accessible / unblocked while the remaining port 208 can be inaccessible / blocked. To provide a second level of therapy having a second drainage rate greater than the first drainage rate (e.g., a second flow resistance less than the first flow resistance), two of the ports 208 can be accessible / unblocked while the remaining port 208 is inaccessible / blocked. As one skilled in the art will appreciate, the flow control elements 211a-d can be actuated such that any combination of the ports 208 are blocked or unblocked to provide a plurality of different levels of therapy.

[0034] To increase the individual levels of therapy that can be provided by the shunt 200, each port 208 can be configured to provide a different level of therapy (e.g., resistance) relative to one another when the shunt 200 is exposed to a given pressure. For example, FIG. 3A illustrates an embodiment of a shunt 200 having four ports 208a-d (e.g., openings), with each port 208a-d having a different dimension. For example, each of the ports 208a-d can have a different diameter that corresponds to a different relative flow rate and / or resistance. In the illustrated embodiment, port 208a has a first diameter, port 208b has a second diameter that is greater than the first diameter, port 208c has a third diameter that is greater than the second diameter, and port 208d has a fourth diameter that is greater than the third diameter. In some embodiments, the diameter of ports 208a-d may range from about 4 micrometers to about 16 micrometers, from about 8 micrometers to about 22 micrometers, from about 15 micrometers to about 60 micrometers, or from about 25 micrometers to about 100 micrometers, while in other embodiments, the diameter of some or all of ports 208a-d may be outside of the aforementioned ranges.

[0035] Each of ports 208a - d can correspond to respective flow control elements 211a - d (omitted in FIG. 3A for clarity). Thus, each of ports 208a - d can be selectively blocked or unblocked by actuating the corresponding flow control elements 211a - d, as described above with respect to FIGS. 2A - 2C. For example, the flow control elements 211a - d can be actuated such that one or more of ports 208a - d has (i) a first fluid flow cross - section that provides a first level of treatment (e.g., when ports 208a - d are fully open and accessible) or (ii) a second fluid flow cross - section that provides a second level of treatment less than the first level of treatment (e.g., when ports 208a - d are at least partially covered by the corresponding flow control elements 211a - d). Further, as described above, any combination of ports 208a - d can be blocked, and any combination of ports 208a - d can be unblocked based on the positioning of the corresponding flow control elements 211a - d.

[0036] Each of ports 208a - d can be associated with a desired fluid flow and / or drainage rate relative to the other ports 208a - c (e.g., when operating under a given pressure). In some embodiments, the relative drainage rate provided through each individual port 208a - d increases by a common value from port 208a to port 208d under a given pressure. For example, port 208a can be associated with a relative drainage rate of about X, port 208b can be associated with a relative drainage rate of about 2X, port 208c can be associated with a relative drainage rate of about 3X, and port 208d can be associated with a relative drainage rate of about 4X. In such embodiments, the ratio of the relative flow rates for ports 208a - d is 1:2:3:4. In such embodiments, the flow control elements 211a - d can be operated to achieve any drainage rate from about X (where only port 208a is unblocked) to about 10X (where all ports 208a - d are unblocked). In embodiments having only three ports 208a - c, the corresponding flow control elements can be operated to achieve any drainage rate from about X (where only port 208a is unblocked) to about 6X (where all ports 208a - c are unblocked). Table 1 below reflects the relative drainage rates (flows) and associated resistance values for an embodiment where the ratio of the relative flow rates for ports 208a - d is 1:2:3:4.

Table 1

[0037] As reflected in Table 1 above, the same relative flow value (Q) can be achieved through different combinations of open and closed ports 208a - d (e.g., flow values of 3, 4, 5, 6, and 7). Thus, in the illustrated embodiment, only 10 individual treatment levels are provided, despite having 15 potential combinations of open and closed ports (16 if all ports 208a - d are closed).

[0038] In other embodiments, the relative drainage rates through each of the ports 208a - d do not increase by a common value from port 208a to port 208d. Instead, they are selectively sized (e.g., to avoid value duplication) to achieve a greater number of individual possible drainage rates. For example, in an embodiment having only three ports 208a - c, port 208a can be associated with a relative drainage rate of about X, port 208b can be associated with a relative drainage rate of about 2X, and port 208c can be associated with a relative drainage rate of about 4X. In such an embodiment, the ratio of the relative flow rates for ports 208a - c is 1:2:4. Ports 208a - c can be selectively blocked and unblocked by corresponding flow control elements 311a - c to achieve various desired drainage rates. For example, when only port 208a is unblocked, the drainage rate is about X; when only port 208b is unblocked, the drainage rate is about 2X; when both ports 208a and 208b are unblocked, the drainage rate is about 3X; when only port 208c is unblocked, the drainage rate is about 4X; when ports 208a and 208c are unblocked, the drainage rate is about 5X; when ports 208b and 208c are unblocked, the drainage rate is about 6X; and when all of ports 208a, 208b, and 208c are unblocked, the drainage rate is about 7X. Unlike a shunt with three ports having a 1:2:3 relative drainage ratio that can provide six individual potential drainage rates as in the above example, a shunt with three ports having a 1:2:4 relative drainage ratio can provide at least seven different potential drainage rates. Thus, by varying the dimensions of the ports 208 as described above, a greater number of relative drainage rates can be obtained with a smaller number of ports 208. In an embodiment having four ports 208, port 208d can have a relative drainage rate of about 8X (e.g., the ratio of the relative flow rates for ports 208a - d is 1:2:4:8) to further increase the number of possible distinct drainage rates. Thus, the user can select which ports 208 are blocked and which are unblocked to achieve any of the desired drainage rates.The following Table 2 reflects the relative drainage rate (flow) and the associated resistance values for an embodiment in which the ratio of the relative flow rates for ports 208a - d is 1:2:4:8. [Table 2]

[0039] Naturally, the ratio of the relative flow rates for ports 208a - c can be a value other than 1:2:4:8 or 1:2:3:4. In some embodiments, for example, the ratio can be 1:1:1:1, 1:1:2:2, 1:1:1:2, etc. In other embodiments, the ratio can be random (e.g., 1:6:2:3, 4:2:5:1, etc.).

[0040] The aforementioned flow characteristics can also be explained from the perspective of the resistance provided by each of the individual ports 208a - d. For example, when unblocked or otherwise accessible, port 208a can have a first resistance, port 208b can have a second resistance less than the first resistance, port 208c can have a third resistance less than the second resistance, and port 208d can have a fourth resistance less than the third resistance. The resistances can have a predetermined ratio. In some embodiments, for example, the ratio of the resistances provided to port 208a, port 208b, port 208c, and port 208d can be 4:3:2:1, 8:4:2:1, 1:1:1:1, or other ratios. The following Table 3 reflects the relative resistances and the associated flow for an embodiment in which the ratio of the relative resistances of ports 208a - d is 4:3:2:1. The following Table 4 reflects the relative resistances and the associated flow for an embodiment in which the ratio of the relative resistances of ports 208a - d is 1:2:4:8. [Table 3] [Table 4]

[0041] As will be understood by those skilled in the art from the disclosure herein, the shunt 200 and other shunts described herein can each have 2, 3, 4, 5, 6, 7, 8, or more ports 208, each with a corresponding flow control element 211. Increasing the number of ports 208 generally increases the number of different drain rates that can be implemented, as the number of unique combinations of blocked and / or unblocked ports also increases as the number of ports 208 increases. As described above, the ports 208 can also be selectively sized to provide a maximum number of potential treatment levels. For example, in an embodiment having two ports, the ratio of the relative flow rates to the ports can be about 1:2, and / or the ratio of the relative resistances to the ports can be about 2:1 (e.g., generating a total of four individual treatment levels). In other embodiments having two ports, the ratio of the relative flow rates is about 1:1, and / or the ratio of the relative resistances is about 1:1. In an embodiment having three ports, the ratio of the relative flow rates to the ports can be about 1:2:4, and / or the ratio of the relative resistances to the ports can be about 4:2:1 (e.g., generating a total of eight individual treatment levels). In other embodiments having three ports, the ratio of the relative flow rates is about 1:1:1 or about 1:2:3, and / or the ratio of the relative resistances is about 1:1:1 or about 3:2:1. In an embodiment having four ports, the ratio of the relative flow rates to the ports can be about 1:2:4:8, and / or the ratio of the relative resistances to the ports can be about 8:4:2:1 (generating a total of sixteen individual treatment levels). In other embodiments having four ports, the ratio of the relative flow rates is about 1:1:1:1 or about 1:2:3:4, and / or the ratio of the relative resistances is about 1:1:1:1 or about 4:3:2:1. In an embodiment having five ports, the ratio of the relative flow rates to the ports can be about 1:2:4:8:16, and / or the ratio of the relative resistances to the ports can be about 16:8:4:2:1 (generating a total of thirty-two individual treatment levels).In other embodiments having five ports, the ratio of the relative flow rates is about 1:1:1:1:1 or about 1:2:3:4:5, and / or the ratio of the relative resistances is about 1:1:1:1:1 or about 5:4:3:2:1.

[0042] FIG. 3B illustrates another embodiment of the shunt 200 where the number of ports 208 (e.g., openings) corresponding to each of the flow control elements 211a-d varies, but the dimensions of each port 208 are the same or at least substantially the same. For example, the drain element 202 can have one port 208 corresponding to the first flow control element 211a, two ports 208 corresponding to the second flow control element 211b, four ports 208 corresponding to the third flow control element 211c, and eight ports 208 corresponding to the fourth flow control element 211d. Since the dimensions of the ports 208 are the same or at least substantially the same, the port 208 corresponding to the first flow control element 211a can provide a relative drain rate of X, the port 208 corresponding to the second flow control element 211b can provide a relative drain rate of about 2X, the port 208 corresponding to the third flow control element 211c can provide a relative drain rate of about 4X, and the port 208 corresponding to the flow control element 211d can provide a relative drain rate of about 8X (e.g., the ratio of the relative flow rates between the ports 208 remains 1:2:4:8). As described above, each of the flow control elements 211a-d can be individually actuated to block and / or unblock the corresponding port 208. Also, as described above, providing ports that promote the aforementioned drain rates increases the number of possible drain rates while reducing the number of flow control elements required. In other embodiments, the number of ports 208 corresponding to each of the flow control elements 211a-d increases by one. In yet other embodiments, the ports 208 do not have the same dimensions.

[0043] In some embodiments, shunt 200 may include a plurality of individual fluidically isolated lumens or channels associated with respective ports 208. In such embodiments, the treatment level (e.g., drainage rate, resistance, etc.) may be determined by the relative dimensions of the lumens rather than the number or size of ports 208. For example, each lumen may have a different dimension to impart a different flow resistance. In such embodiments, shunt 200 may still include ports 208 of different sizes (FIG. 3A) or a different number of ports 208 (FIG. 3B) to provide a visual cue to a healthcare provider reflecting the relative fluid resistance of the corresponding channels (e.g., one opening may mean that the corresponding lumen has a first resistance, two openings may mean that the corresponding lumen has a second resistance less than the first resistance, etc.).

[0044] The above description mainly explains the potential flow rates and resistances under a binary setting where ports 208a-d are either open or closed. However, in some embodiments, gate element 216 can be operated to occupy one or more positions between a fully open state and a fully closed state of ports 208a-d. This can further increase the number of individual treatment levels that shunt 200 can provide. In yet other embodiments, gate element 216 may allow some fluid to leak through ports 208a-d even in the closed position (e.g., gate element 216 does not form a perfect fluid seal with ports 208a-d when in the closed position).

[0045] The techniques and operating assemblies described above can also be used with other types of shunts and drainage elements. For example, FIGS. 4A and 4B illustrate selected features of a shunt 400 having a drainage plate 440 configured in accordance with a selected embodiment of the present technology. More specifically, FIG. 4A is a partial isometric view of the plate 440, and FIG. 4B is a partial schematic top-down view of the plate 440. The plate 440 includes a plurality of inlet ports 408 that allow fluid to flow into a plurality of corresponding channels 422. The channels 422 enter the lumen 405 and empty through a plurality of outlet ports 409. Accordingly, the plurality of inlet ports 408 and / or channels 422 are arranged as parallel fluid resistances and can thus exhibit flow characteristics similar to those described above with respect to the shunt 200 (FIGS. 2A-3B). The lumen 405 can direct fluid towards a desired outflow location (e.g., the bleb space) and / or an elongated drainage element (not shown).

[0046] The shunt 400 can include a flow control mechanism (not shown) operably coupled to the drain plate 440 to control the flow of fluid through the channel 422. In some embodiments, the flow control mechanism includes a plurality of individually operable flow control elements associated with the individual inlet ports 408 and channels 422. For example, in some embodiments, a flow control mechanism substantially similar to the flow control mechanism 210 described with respect to FIGS. 2A-2C can be disposed on the plate 440 such that the flow control elements 211a-d interface with the inlet ports 408. In some embodiments, aspects of the flow control mechanism 210 can be slightly modified to account for different structures of the shunt 400. For example, the fixed elements cannot extend around the entire shunt and can instead be fixed to the upper surface of the plate 440 (e.g., via welding, adhesion, or other suitable adhesives). Regardless of its configuration, the flow control mechanism can be positioned such that the individual flow control elements (e.g., the flow control elements 211a-d of FIGS. 2A-2C) are positioned to control the flow of fluid through the individual ports 408. For example, the flow control elements 211a-d (FIGS. 2B and 2C) can be selectively actuated independently to block and / or unblock the flow through the corresponding channels 422. In other embodiments, other suitable flow control elements configured to at least partially block and / or unblock the flow of fluid through the channel 422 can be used.

[0047] In some embodiments, channels 422 may each have the same or approximately the same flow resistance. In embodiments where channels 422 have the same or approximately the same flow resistance, opening additional channels 422 is expected to result in a step - increase in the drainage rate, and blocking additional channels 422 is expected to result in a step - decrease in the drainage rate. For example, moving from a single open channel 422 to two open channels 422 is generally expected to double the drainage rate, while moving from two open channels 422 to three open channels 422 is generally expected to increase the drainage rate by 50 percent. However, since the resistance and flow when only the first lumen is unblocked are the same as the resistance and flow when only the second lumen is unblocked, the total number of intrinsic resistances, i.e., the achievable flow rate, is not maximized.

[0048] In other embodiments, channels 422 may have different resistances and thus different relative drainage rates. For example, in some embodiments, each individual channel 422 may be associated with a desired drainage rate and / or resistance relative to the others. For example, the first channel may be associated with a drainage rate of about X, the second channel may be associated with a drainage rate of about 2X, the third channel may be associated with a drainage rate of about 4X, and so on. As explained above with respect to port 208, when each channel 422 is associated with a different drainage rate, more drainage rates can be achieved with fewer channels 422. The flow resistance through channels 422, and thus the drainage rate through channels 422, can vary based on, for example, the length and / or diameter of the channel. The length of the channel is generally proportional to the resistance of the channel, while the diameter of the channel is generally inversely proportional to the resistance of the channel. Thus, each individual channel 422 may have a unique length, diameter, or combination of length and diameter that gives a particular resistance. The individual channels 422 can then be selectively opened (or closed) to achieve the desired flow rate.

[0049] The flow characteristics through parallel fluid resistances such as shunt 400 (and shunt 200) can be similar to the current flowing through an electrical circuit having a plurality of resistances arranged in parallel. For example, FIG. 4C is a schematic diagram of an electrical circuit 650 having a plurality of resistances R 1~4 arranged in parallel. Each resistance R 1~4 is similar to an individual port or channel of a parallel resistance shunt (e.g., ports 208a-d of shunt 200, port 408 of shunt 400, or channel 422 of shunt 400). To control the current flow through the circuit, a plurality of switches S 1~4 can each complete or disconnect the circuit through an individual resistance R 1~4 . This is similar to each individual port being able to transition between an open (e.g., blocked) state and a closed (e.g., unblocked) state. Two or more switches S 1~4 closed to complete circuit 450 affect the current flow through circuit 450 in a manner similar to two or more ports being open within a parallel resistance shunt. The current is shown flowing through circuit 450 in a first direction, but the current can alternatively flow through circuit 450 in a second direction opposite the first direction in a manner similar to how the parallel resistance shunts described herein can operate with fluid flowing through the shunt in either direction.

[0050] The present technology also provides a shunt system having a plurality of inlet ports that operate as series fluid resistors. For example, FIGS. 5A and 5B illustrate the features of a shunt 500 having a drainage plate 540 configured to function as a series fluid resistor. More specifically, FIG. 5A is a top-down partial isometric view of the drainage plate 540, and FIG. 5B is a bottom-up partial isometric view of the drainage plate 540. Unlike the drainage plate 440 (FIG. 4A), the drainage plate 540 includes a single inlet port 508 that allows fluid to flow into the channel 522. The channel 522 includes a plurality of outlet ports 509 that allow fluid to flow from the channel 522 into a lumen (e.g., lumen 405 described with respect to FIGS. 4A and 4B) that directs the fluid towards a desired outflow location (e.g., a bleb space) and / or an elongated drainage element (not shown). The plurality of outlet ports 509 can be arranged in series along the length of the channel 522 and / or can be fluidly coupled to the channel 522 by a plurality of conduits extending from the channel 522. In other embodiments, the orientation of the drainage plate 540 can be reversed such that fluid flows in the opposite direction (e.g., from the plurality of outlet ports 509 to the single inlet port 508).

[0051] The shunt 500 can be operably coupled to a drainage plate 540 and include a flow control mechanism (not shown) for controlling the flow of fluid from the outflow port 509 into the lumen. The flow control mechanism can include a plurality of individually operable flow control elements associated with the individual outflow ports 509. For example, in some embodiments, a flow control mechanism substantially similar to the flow control mechanism 210 (Figs. 2A-2C) described herein can be disposed on the plate 540 such that the flow control elements 211a-d interface with the outflow ports 509. In such embodiments, the plate 540 can be at least partially transmissive (e.g., transparent) to at least some forms of energy, such as laser energy having a selected wavelength (e.g., from about 500 nm to about 600 nm, etc.). In other embodiments, other suitable flow control elements configured to at least partially block and / or unblock the flow of fluid through the outflow port 509 can be used.

[0052] The plate 540 is configured to function as a series resistance. For example, the resistance is provided by the channel 522 (rather than the inflow port 508 and / or the outflow port 509) and is based on the distance between the inflow port 508 and the closest open outflow port 509. For example, if the outflow port 509 that is farthest and spaced from the inflow port 508 is the only outflow port 509 that is open, the resistance to flow is greatest (e.g., because the fluid has to travel the maximum distance through the channel 522). If the outflow port 509 closest to the inflow port 508 is opened, then the resistance is least (e.g., because the fluid has to travel the shortest distance through the channel 522). In such embodiments, the channels / openings react as if they were in series, and thus, the number of individual resistances and the drainage rate are generally equal to the number of outflow openings 509.

[0053] The flow characteristics through a series fluid resistance such as the shunt 500 can be similar to the current flowing through an electrical circuit having a plurality of resistances arranged in series. For example, Fig. 6C shows four resistors R in series a~dIt is a schematic diagram of an electric circuit 550 having. Each resistor R a~d is similar to the individual ports of a series resistance shunt (e.g., port 509 of shunt 500). To control the current flow through the circuit, a plurality of switches S a~d can complete or disconnect the circuit. This is similar to each individual port being able to transition between an open (e.g., blocked) state and a closed (e.g., unblocked) state. Two or more switches S a~d that are closed to complete the circuit 550 affect the current flow through the circuit 550 in a manner similar to two or more ports being open in a series resistance shunt. The current is shown flowing through circuit 650 in a first direction, but the current can alternatively flow through circuit 650 in a second direction opposite the first direction in a manner similar to how the series resistance shunt described herein can operate with fluid flowing through the shunt in either direction.

[0054] FIG. 6 is an isometric view of a shunt 600 constructed in accordance with a selected embodiment of the present technology. The shunt 600 includes an elongate tube 602 having a first end portion 604 and a second end portion 606. The first end portion 604 is connected to a plate 640. The plate 640 can be substantially similar to the plates 440 and / or 540 described above with respect to FIGS. 4A and 4B, and FIGS. 5A and 5B, respectively. The first end portion 604 can be fluidly coupled within the interior of the plate 640 (e.g., lumen 405 - FIG. 4A) and configured to receive fluid therefrom. The second end portion 606 can include one or more ports (not shown). When the shunt 600 is implanted within the eye, the first end portion 604 and the plate 640 can be present within the anterior chamber, and the second end portion 606 can be present within a desired outflow location (e.g., bleb space). In other embodiments, the first end portion 604 and the plate 640 can be present within a desired outflow location, and the second end portion 606 can be present within the anterior chamber. Regardless of the orientation of the shunt 600, the shunt 600 is configured to drain water from the anterior chamber when the shunt 600 is implanted within the eye. In some embodiments, the plate 640 can at least partially fix the shunt 600 in a desired position. The shunt 600 can optionally have additional features that assist in fixing the shunt 600 in a predetermined position when implanted within the eye. For example, the shunt 600 can include arms, anchors, plates, or other suitable features for fixing the shunt 600 to natural tissue.

[0055] The present technology further includes, for example, a shunt system as described herein and a method of shunting fluid through the shunt (e.g., for draining aqueous humor from the anterior chamber to treat glaucoma). The method can incorporate any of the techniques described above, including, for example, selectively actuating one or more flow control elements to open and / or close one or more ports (e.g., an inflow port) on the shunt to achieve a target resistance and / or flow. The method can also include selectively actuating one or more flow control elements to open and / or close one or more ports until a target intraocular pressure is achieved.

[0056] In some embodiments, the ports can all be unblocked simultaneously to provide minimal resistance and maximum flow for a given pressure. This can be done in a healthcare provider's office to rapidly reduce intraocular pressure. Once the target intraocular pressure is achieved, some or all of the ports can be closed to provide a flow and resistance suitable for long-term treatment. Without intending to be bound by theory, the use of an adjustable shunt as provided herein may be able to safely provide higher flow rates and lower resistance than conventional static (e.g., non-adjustable) shunts. For example, conventional static shunts generally do not provide high flow rates or low resistance to avoid inducing hypotony. In contrast, the shunts of the present technology can provide high flow rates and low resistance (e.g., by opening all ports), which, if left unchanged for a long period, can lead to hypotony. However, before hypotony develops, a healthcare provider can adjust the shunt to reduce flow and increase resistance. One of the expected advantages of this is that the healthcare provider can more rapidly reduce the intraocular pressure within the patient.

[0057] Examples Some aspects of the present technology are described in the following examples: 1. A system for draining fluid, A drainage element having a first end region positionable within a first body region and a second end region positionable within a second body region, the first end region including a first port, a second port, and a third port, the drainage element, A flow control mechanism for controlling the flow of fluid through the drainage element, A first flow control element movable between a first open position that allows fluid to flow into the drainage element through the first port and a first closed position that substantially prevents fluid from flowing into the drainage element through the first port, A second flow control element movable between a second open position that allows fluid to flow into the drainage element through the second port and a second closed position that substantially prevents fluid from flowing into the drainage element through the second port, A third flow control element movable between a third open position that allows fluid to flow into the drainage element through the third port and a third closed position that substantially prevents fluid from flowing into the drainage element through the third port, and A flow control mechanism in which the first flow control element, the second flow control element, and the third flow control element are movable independently between their respective open and closed positions, the system comprising. 2. When the first flow control element is in the first open position, the second flow control element is in the second closed position, and the third flow control element is in the third closed position, the system is configured to provide a first relative resistance to fluid flow, When the second flow control element is in the second open position, the first flow control element is in the first closed position, and the third flow control element is in the third closed position, the system is configured to provide a second relative resistance, The system according to Example 1, wherein when the third flow control element is in the third open position, the first flow control element is in the first closed position, and the second flow control element is in the second closed position, the system is configured to provide a third relative resistance. 3. The system according to Example 2, wherein the second relative resistance is less than the first relative resistance and the third relative resistance is less than the first relative resistance. 4. The system according to Example 3, wherein the ratio among the first relative resistance, the second relative resistance, and the third relative resistance is about 4:2:1. 5. The system according to Example 3, wherein the ratio among the first relative resistance, the second relative resistance, and the third relative resistance is about 3:2:1. 6. The system according to Example 2, wherein the ratio among the first relative resistance, the second relative resistance, and the third relative resistance is about 1:1:1. 7. When the first flow control element is in the first open position, the second flow control element is in the second closed position, and the third flow control element is in the third closed position, the system is configured to provide a first relative drainage rate. When the second flow control element is in the second open position, the first flow control element is in the first closed position, and the third flow control element is in the third closed position, the system is configured to provide a second relative drainage rate. The system according to Example 1, wherein when the third flow control element is in the third open position, the first flow control element is in the first closed position, and the second flow control element is in the second closed position, the system is configured to provide a third relative drainage rate. 8. The system according to Example 7, wherein the second relative drainage rate is greater than the first relative drainage rate, and the third relative drainage rate is greater than the second relative drainage rate. 9. The system according to Example 8, wherein the ratio among the first relative drainage rate, the second relative drainage rate, and the third relative drainage rate is about 1:2:4. 10. The system according to Example 8, wherein the ratio among the first relative drainage rate, the second relative drainage rate, and the third relative drainage rate is about 1:2:3. 11. The system according to Example 7, wherein the ratio among the first relative drainage rate, the second relative drainage rate, and the third relative drainage rate is about 1:1:1. 12. The system according to any one of Examples 1 to 11, wherein the drainage element has a first channel fluidly coupled to the first port, a second channel fluidly coupled to the second port, and a third channel fluidly coupled to the third port. 13. The system according to embodiment 12, wherein the first channel is configured to provide a relative resistance greater than that of the second channel, and the second channel is configured to provide a relative resistance greater than that of the third channel. 14. The system according to embodiment 13, wherein the first channel has a first cross-sectional area, the second channel has a second cross-sectional area greater than the first cross-sectional area, and the third channel has a third cross-sectional area greater than the second cross-sectional area. 15. The system according to any one of embodiments 1 to 14, wherein the first port has a first area, the second port has a second area greater than the first area, and the third port has a third area greater than the second area. 16. The system according to any one of embodiments 1 to 15, wherein the first port includes a single opening, the second port includes two openings, and the third port includes three or more openings. 17. The system according to any one of embodiments 1 to 16, wherein the first port is a first inlet port, the second port is a second inlet port, and the third port is a third inlet port. 18. The system according to any one of embodiments 1 to 17, wherein the first body region is the anterior chamber and the fluid is water. 19. A system for draining fluid, a drainage element having a first end region positionable within a first body region and a second end region positionable within a second body region, the first end region including a first inlet port and a second inlet port, wherein the system is configured to provide a first relative drainage rate through the drainage element when the first inlet port is unblocked and the second inlet port is blocked; a drainage element, wherein the system is configured to provide a second relative drainage rate through the drainage element greater than the first relative drainage rate when the second inlet port is unblocked and the first inlet port is blocked; a flow control mechanism, a first flow control element configured to selectively control the flow of fluid through a first inlet port, and a second flow control element configured to selectively control the flow of fluid through a second inlet port, a flow control mechanism, wherein the first flow control element and the second flow control element are operable independently. 20. The system according to embodiment 19, wherein the ratio between the first relative drainage rate and the second relative drainage rate is 1:2. 21. The system according to embodiment 20, wherein when both the first inlet port and the second inlet port are unblocked, the system is configured to provide a third relative drainage rate through a drainage element that is greater than the first relative drainage rate and the second relative drainage rate. 22. The system according to embodiment 21, wherein the ratio among the first, second, and third relative drainage rates is 1:2:3. 23. The system according to any one of embodiments 19 to 22, wherein the first inlet port includes a single opening and the second inlet port includes a plurality of openings. 24. The system according to any one of embodiments 19 to 23, wherein the first inlet port has a first area and the second inlet port has a second area that is larger than the first area. 25. The system according to any one of embodiments 19 to 24, wherein the drainage element includes (i) a first lumen extending between the first inlet port and a second end region, and (ii) a second lumen extending between the second inlet port and the second end region, and the first lumen is configured to provide a resistance to the flow of a fluid different from that of the second lumen. 26. The system according to any one of embodiments 19 to 25, wherein the drainage element further includes a third inlet port, and when the third inlet port is unblocked and the first and second inlet ports are blocked, the system is configured to provide a third relative drainage rate through the drainage element. 27. The system according to embodiment 26, wherein the ratio among the first relative drainage rate, the second relative drainage rate, and the third relative drainage rate is about 1:2:3. 28. The system according to Example 26, wherein the ratio among the first relative drainage rate, the second relative drainage rate, and the third relative drainage rate is about 1:2:4. 29. The system according to Example 25, wherein the drainage element further comprises a fourth inflow port, and when the fourth inflow port is unblocked and the first, second, and third inflow ports are blocked, the system is configured to provide a fourth relative drainage rate through the drainage rate, and the ratio of the first, second, third, and fourth relative drainage rates is about 1:2:4:8. 30. The system according to any one of Examples 19 to 29, wherein the first body region is the anterior chamber of the eye and the fluid is water. 31. The system according to any one of Examples 19 to 30, wherein the drainage element includes a plate extending from the first end portion, and the plate includes the first and second inflow ports. 32. An adjustable shunt, comprising a drainage element having a first end portion positionable within the anterior chamber of the patient's eye and a second end portion positionable within a target outflow location of the patient, wherein the first end portion includes at least three inflow ports, the first inflow port is configured to provide a first drainage rate when only the first inflow port is open, the second inflow port is configured to provide a second drainage rate greater than the first drainage rate when only the second inflow port is open, and the third inflow port is configured to provide a third drainage rate greater than the second drainage rate when only the third inflow port is open, the second end portion includes at least one outflow port, a lumen extending through the drainage element from the first end portion to the second end portion to fluidly connect at least three inflow ports and at least one outflow port, and the drainage element; A flow control mechanism having at least three individually operable flow control elements, wherein a first flow control element is selectively operable to block and unblock a first inlet port, a second flow control element is selectively operable to block and unblock a second inlet port, and a third flow control element is selectively operable to block and unblock a third inlet port, and an adjustable shunt comprising the flow control mechanism. 33. The adjustable shunt according to embodiment 32, wherein the first drainage rate, the second drainage rate, and the third drainage rate are predetermined relative drainage rates, the first drainage rate is about X, the second drainage rate is about 2X, and the third drainage rate is about 3X. 34. The adjustable shunt according to embodiment 32, wherein the first drainage rate, the second drainage rate, and the third drainage rate are predetermined relative drainage rates, the first drainage rate is about X, the second drainage rate is about 2X, and the third drainage rate is about 4X. 35. The adjustable shunt according to embodiment 34, configured to provide a fourth relative drainage rate different from the first drainage rate, the second drainage rate, and the third drainage rate when two or more inlet ports are open. 36. The shunt is when only the first inlet port and the second inlet port are open, a fourth drainage rate of about 3X, when only the first inlet port and the third inlet port are open, a fifth drainage rate of about 5X, when only the second inlet port and the third inlet port are open, a sixth drainage rate of about 6X, and when the first inlet port, the second inlet port, and the third inlet port are open, an adjustable shunt according to embodiment 34 configured to provide an additional predetermined relative drainage rate including a seventh drainage rate of about 7X. 37. The adjustable shunt according to embodiment 36, wherein the flow control element is selectively operable to achieve any of the predetermined relative drainage rates. 38. A method of treating glaucoma, comprising Draining water from the anterior chamber of the eye to a target drainage location using an adjustable shunt, wherein the adjustable shunt a first inlet port fluidly coupled within the shunt, a second inlet port fluidly coupled within the shunt, a first flow control element movable between a first open position that allows fluid to flow into the shunt through the first inlet port and a first closed position that substantially prevents fluid from flowing into the shunt through the first inlet port, a second flow control element movable between a second open position that allows fluid to flow into the shunt through the first inlet port and a second closed position that substantially prevents fluid from flowing into the shunt through the first inlet port, and draining, selectively adjusting the drainage rate of the water by actuating the first flow control element and / or the second flow control element between their respective open and closed positions. 39. The method of embodiment 38, wherein the first inlet port provides a first drainage rate when only the first inlet port is unblocked, and the second inlet port provides a second drainage rate greater than the first drainage rate when only the second inlet port is unblocked. 40. The method of embodiment 38 or 39, wherein actuating at least one of the individually actuable flow control elements includes applying energy to at least one of the individually actuable flow control elements. 41. The method of embodiment 40, wherein the energy is non-invasive energy. 42. An adjustable shunt comprising a drainage element having a first end portion positionable within the anterior chamber of a patient's eye and a second end portion positionable within a target drainage location of the patient, wherein the first end portion includes a plurality of inlet ports, the plurality of inlet ports including at least a first inlet port and a second inlet port, and the second end portion includes at least one outlet port. The lumen extends from a first end portion to a second end portion through a drainage element, fluidly connecting a plurality of inflow ports and at least one outflow port, the drainage element; A flow control mechanism configured to control the flow of fluid through the plurality of inflow ports, the flow control mechanism comprising: A first flow control element configured to control the flow of fluid through a first inflow port, and A second flow control element configured to control the flow of fluid through a second inflow port, The first flow control element and the second flow control element are independently operable, such that the first flow control element moves independently of the second flow control element to selectively block and / or unblock the first inflow port, and the second flow control element moves independently of the first flow control element to selectively block and / or unblock the second inflow port. A flow control mechanism, and an adjustable shunt comprising the same. 43. The adjustable shunt of embodiment 42, wherein the first inflow port and the second inflow port have different diameters. 44. The adjustable shunt of embodiment 42, wherein the first inflow port comprises a single inflow opening and the second inflow port comprises at least two inflow openings. 45. The first inflow port is configured to provide a first drainage rate through the shunt when only the first inflow port is unblocked, and the second inflow port is configured to provide a second drainage rate through the shunt that is greater than the first drainage rate when only the second inflow port is unblocked. The adjustable shunt according to any one of embodiments 42 to 44. 46. The drainage element includes a plate extending from the first end portion, the plate including a plurality of inflow ports. The adjustable shunt according to any one of embodiments 42 to 45. 47. The plate A first channel fluidly connecting the first inflow port and the lumen, and A second channel fluidly connecting the second inflow port and the lumen, The adjustable shunt described in Example 46, in which the first channel is separated from the second channel. 48. The adjustable shunt described in Example 47, in which the first flow control element is positioned between the first channel and the lumen, and the second flow control element is positioned between the second channel and the lumen. 49. The adjustable shunt described in Example 47, in which the first channel extends between the first flow control element and the lumen, and the second channel extends between the second flow control element and the lumen.

[0058] Conclusion The above detailed description of embodiments of the present technology is not intended to be exhaustive or to limit the present technology to the detailed forms disclosed above. Specific embodiments of the technology and examples of the technology have been described above for illustrative purposes, but as will be recognized by those skilled in the art, various equivalent modifications are possible within the scope of the technology. For example, any of the features of the intraocular shunts described herein can be combined with any of the features of the other intraocular shunts described herein, and vice versa. Further, although steps are presented in a given order, in alternative embodiments the steps may be performed in a different order. The various embodiments described herein may also be combined to provide further embodiments.

[0059] From the above, although specific embodiments of the present technology have been described herein for illustrative purposes, well-known structures and functions associated with intraocular shunts have not been shown or described in detail so as not to unnecessarily obscure the description of embodiments of the present technology. Where the context permits, singular or plural terms may also include plural or singular terms, respectively.

[0060] Unless the context clearly requires otherwise, throughout the description and the examples, words such as "comprise", "comprising", etc. should be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, they should be interpreted as "including, but not limited to". As used herein, the terms "connected", "coupled", or any variation thereof, mean any direct or indirect connection or coupling between two or more elements, and the connection or coupling between elements can be physical, logical, or a combination thereof. Also, as used herein, the words "herein", "above", "below", and words of similar import refer to the entire present application and not to a particular part of the present application. Wherever possible in the context, the words in the above detailed description using the singular or plural number may also include the plural or singular number respectively. As used herein, a phrase such as "and / or" within "A and / or B" refers to A only, B only, and both A and B. Additionally, the term "comprising" is used throughout to mean including at least the recited features so that any greater number of the same features and / or additional types of other features are not excluded. While specific embodiments have been described herein for purposes of illustration, it will be understood that various modifications can be made without departing from the technology. Further, while the advantages associated with some embodiments of the technology are described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments necessarily exhibit such advantages in order to fall within the scope of the technology. Accordingly, the present disclosure and related technologies can encompass other embodiments not expressly shown or described herein.

Claims

Claim 1 A system for draining a fluid, comprising: a drainage element having a first end region positionable within a first body region and a second end region positionable within a second body region, the first end region including a first port, a second port, and a third port; a flow control mechanism for controlling the flow of fluid through the drainage element; a first flow control element movable between a first open position that permits fluid to flow into the drainage element via the first port and a first closed position that substantially prevents fluid from flowing into the drainage element via the first port; a second flow control element movable between a second open position that permits fluid to flow into the drainage element via the second port and a second closed position that substantially prevents fluid from flowing into the drainage element via the second port; a third flow control element movable between a third open position that permits fluid to flow into the drainage element via the third port and a third closed position that substantially prevents fluid from flowing into the drainage element via the third port; wherein the first flow control element, the second flow control element, and the third flow control element are each independently movable between their respective open and closed positions; a flow control mechanism; A system comprising the above. Claim 2 When the first flow control element is in the first open position, the second flow control element is in the second closed position, and the third flow control element is in the third closed position, the system is configured to provide a first relative resistance to fluid flow; When the second flow control element is in the second open position, the first flow control element is in the first closed position, and the third flow control element is in the third closed position, the system is configured to provide a second relative resistance to fluid flow; The system according to claim 1, wherein when the third flow control element is in the third open position, the first flow control element is in the first closed position, and the second flow control element is in the second closed position, the system is configured to provide a third relative resistance to fluid flow. Claim 3 The system according to claim 2, wherein the second relative resistance is less than the first relative resistance, and the third relative resistance is less than the first relative resistance.

4. The system according to claim 3, wherein the ratio among the first relative resistance, the second relative resistance, and the third relative resistance is about 4:2:

1.

5. The system according to claim 3, wherein the ratio among the first relative resistance, the second relative resistance, and the third relative resistance is about 3:2:

1.

6. The system according to claim 2, wherein the ratio among the first relative resistance, the second relative resistance, and the third relative resistance is about 1:1:

1.

7. When the first flow control element is within the first open position, the second flow control element is within the second closed position, and the third flow control element is within the third closed position, the system is configured to provide a first relative drainage rate. When the second flow control element is within the second open position, the first flow control element is within the first closed position, and the third flow control element is within the third closed position, the system is configured to provide a second relative drainage rate. The system according to claim 1, wherein when the third flow control element is within the third open position, the first flow control element is within the first closed position, and the second flow control element is within the second closed position, the system is configured to provide a third relative drainage rate.

8. The system according to claim 7, wherein the second relative drainage rate is greater than the first relative drainage rate, and the third relative drainage rate is greater than the second relative drainage rate.

9. The system according to claim 8, wherein the ratio among the first relative drainage rate, the second relative drainage rate, and the third relative drainage rate is about 1:2:

4.

10. The system according to claim 8, wherein the ratio among the first relative drainage rate, the second relative drainage rate, and the third relative drainage rate is about 1:2:

3.

11. The system according to claim 7, wherein the ratio among the first relative drainage rate, the second relative drainage rate, and the third relative drainage rate is about 1:1:

1.

12. The system according to claim 1, wherein the drainage element has a first channel fluidly coupled to the first port, a second channel fluidly coupled to the second port, and a third channel fluidly coupled to the third port.

13. The system according to claim 12, wherein the first channel is configured to provide a relative resistance greater than that of the second channel, and the second channel is configured to provide a relative resistance greater than that of the third channel.

14. The system according to claim 13, wherein the first channel has a first cross-sectional area, the second channel has a second cross-sectional area greater than the first cross-sectional area, and the third channel has a third cross-sectional area greater than the second cross-sectional area.

15. The system according to claim 1, wherein the first port has a first area, the second port has a second area greater than the first area, and the third port has a third area greater than the second area.

16. The system according to claim 1, wherein the first port includes a single opening, the second port includes two openings, and the third port includes three or more openings.

17. The system according to claim 1, wherein the first port is a first inflow port, the second port is a second inflow port, and the third port is a third inflow port.

18. The system according to claim 1, wherein the first body region is the anterior chamber and the fluid is water.

19. A system for draining fluid, a drainage element having a first end region positionable within a first body region and a second end region positionable within a second body region, the first end region including a first inflow port and a second inflow port, wherein the system is configured to provide a first relative drainage rate through the drainage element when the first inflow port is unblocked and the second inflow port is blocked, a drainage element configured such that when the second inflow port is unblocked and the first inflow port is blocked, the system provides a second relative drainage rate through the drainage element that is greater than the first relative drainage rate; and a flow control mechanism, a first flow control element configured to selectively control the flow of fluid through the first inlet port, and a second flow control element configured to selectively control the flow of fluid through the second inlet port, and a flow control mechanism in which the first flow control element and the second flow control element are operable independently A system comprising.

20. The system according to claim 19, wherein the ratio between the first relative drainage rate and the second relative drainage rate is 1:

2.

21. The system according to claim 20, wherein when both the first inlet port and the second inlet port are unblocked, the system is configured to provide a third relative drainage rate through the drainage element that is greater than the first relative drainage rate and the second relative drainage rate.

22. The system according to claim 21, wherein the ratio between the first, second, and third relative drainage rates is 1:2:

3.

23. The system according to claim 19, wherein the first inlet port includes a single opening and the second inlet port includes a plurality of openings.

24. The system according to claim 19, wherein the first inlet port has a first area and the second inlet port has a second area that is larger than the first area.

25. The drainage element includes (i) a first lumen extending between the first inlet port and the second end region, and (ii) a second lumen extending between the second inlet port and the second end region, and the first lumen is configured to provide a resistance to the flow of a fluid different from that of the second lumen. The system according to claim 19.

26. The drainage element further includes a third inlet port, and when the third inlet port is unblocked and the first and second inlet ports are blocked, the system is configured to provide a third relative drainage rate through the drainage element. The system according to claim 19.

27. The system according to claim 26, wherein the ratio between the first relative drainage rate, the second relative drainage rate, and the third relative drainage rate is approximately 1:2:

3.

28. The system according to claim 26, wherein the ratio between the first relative drainage rate, the second relative drainage rate, and the third relative drainage rate is approximately 1:2:

4.

29. The drainage element further comprises a fourth inlet port, and when the fourth inlet port is unblocked and the first, second, and third inlet ports are blocked, the system is configured to provide a fourth relative drainage rate through the drainage element, and the ratio of the first, second, third, and fourth relative drainage rates is about 1:2:4:8, the system according to claim 25.

30. The system according to claim 19, wherein the first body region is the anterior chamber of the eye and the fluid is water.

31. The system according to claim 19, wherein the drainage element includes a plate extending from a first end portion, and the plate includes the first and second inlet ports.

32. An adjustable shunt, A drainage element having a first end portion positionable within the anterior chamber of a patient's eye and a second end portion positionable within a target outflow location of the patient, The first end portion includes at least three inlet ports, the first inlet port is configured to provide a first drainage rate when only the first inlet port is open, the second inlet port is configured to provide a second drainage rate greater than the first drainage rate when only the second inlet port is open, and the third inlet port is configured to provide a third drainage rate greater than the second drainage rate when only the third inlet port is open, The second end portion includes at least one outflow port, A drainage element in which a lumen extends through the drainage element from the first end portion to the second end portion to fluidly connect the at least three inlet ports and the at least one outflow port, A flow control mechanism having at least three individually operable flow control elements, the first flow control element being selectively operable to block and unblock the first inlet port, the second flow control element being selectively operable to block and unblock the second inlet port, and the third flow control element being selectively operable to block and unblock the third inlet port, a flow control mechanism Comprising an adjustable shunt.

33. The first drainage rate, the second drainage rate, and the third drainage rate are predetermined relative drainage rates, the first drainage rate is about X, the second drainage rate is about 2X, and the third drainage rate is about 3X. The adjustable shunt according to claim 32.

34. The first drainage rate, the second drainage rate, and the third drainage rate are predetermined relative drainage rates, the first drainage rate is about X, the second drainage rate is about 2X, and the third drainage rate is about 4X. The adjustable shunt according to claim 32.

35. When two or more inflow ports are open, the shunt is configured to provide a fourth relative drainage rate different from the first drainage rate, the second drainage rate, and the third drainage rate. The adjustable shunt according to claim 34.

36. The shunt is when only the first inflow port and the second inflow port are open, a fourth drainage rate of about 3X, when only the first inflow port and the third inflow port are open, a fifth drainage rate of about 5X, when only the second inflow port and the third inflow port are open, a sixth drainage rate of about 6X, and when the first inflow port, the second inflow port, and the third inflow port are open, configured to provide an additional predetermined relative drainage rate including a seventh drainage rate of about 7X. The adjustable shunt according to claim 34.

37. The flow control element is selectively operable to achieve any of the predetermined relative drainage rates. The adjustable shunt according to claim 36.

Images