Fluid drainage device, system, and method

Abstract

To provide an excellent shunt or the like.SOLUTION: Glaucoma shunts for draining fluid from an eye to surrounding tissue and being implantable within eye tissue include a shunt body formed from microporous materials arranged to form a reservoir within the shunt body, and a conduit having a proximal end in fluid communication with the reservoir and an opposing distal end, the distal end being insertable into the eye to facilitate drainage of fluid into the conduit via the distal end, wherein the conduit and the reservoir together define a flow passage along which drainage of fluid flows through the conduit, to the reservoir, and into surrounding tissue via the microporous material, wherein the flow passage presents a variable flow resistance along the conduit that has a plurality of sequential flow resistances with first and second flow resistances defined therein so that the first flow resistance is different from the second flow resistance.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 63 / 276,183, filed November 5, 2021, and U.S. Patent Application No. 17 / 980,431, filed November 3, 2022, each of which is incorporated by reference herein in its entirety.

[0002] Field The present disclosure relates generally to devices, systems and methods for draining fluid and redirecting the fluid to be reabsorbed elsewhere within the body. More particularly, the present disclosure relates to devices, systems and methods for draining aqueous humor from the anterior chamber of a patient's eye for reabsorption by the body. [Background technology]

[0003] background Various medical interventions involve draining excess fluid, e.g., bodily fluid, from one part of the body and redirecting it to another part of the body where it can be reabsorbed. In certain instances, this drainage is achieved through minimally invasive procedures such as endoscopic ventriculostomy (ETV) and choroid plexus ablation (CPC). In other instances, this drainage is performed postoperatively via an implantable medical device, such as a shunt. Having proven useful in a variety of medical procedures, various types of shunts have been used to treat a number of conditions, such as hydrocephalus and glaucoma.

[0004] Without treatment, excess fluid can cause unhealthy increases in pressure. For example, glaucoma is a progressive eye disease characterized by increased intraocular pressure. Aqueous humor is the fluid that fills the anterior chamber of the eye and contributes to intraocular pressure, or intraocular fluid pressure. This increase in intraocular pressure usually occurs because an insufficient amount of aqueous humor is absorbed by the body. In some cases, aqueous humor is not absorbed quickly enough, or even at all, while in other cases, aqueous humor is additionally or alternatively produced too quickly. Increased intraocular pressure causes gradual, sometimes permanent, loss of vision in the affected eye.

[0005] Many attempts have been made to treat glaucoma. However, some conventional devices are relatively bulky and lack the flexibility, conformability, and device / tissue attachment necessary to avoid relative movement between the device and surrounding tissue. Such movement can continuously irritate the surrounding tissue, potentially causing irritation at the implant site. This irritation can then lead to increased chronic inflammatory tissue response, excessive scarring at the device site, and an increased risk of device erosion due to conjunctivitis and endophthalmitis. Scar tissue effectively prevents aqueous humor absorption without causing erosion. These complications can prevent the device from functioning properly. This results in a gradual increase in intraocular pressure and the progression of glaucoma. Summary of the Invention

[0006] Abstract According to one example ("Example 1"), there is provided a glaucoma shunt for draining fluid from an eye to tissue surrounding the eye, the glaucoma shunt being at least partially implantable within the tissue of the eye, the glaucoma shunt including: a shunt body formed from a microporous material arranged to form a reservoir within the shunt body; and a conduit having a proximal end in fluid communication with the reservoir and a distal end opposite the proximal end, the distal end of the conduit being insertable into the eye to facilitate drainage of fluid into the conduit through the distal end of the conduit, the conduit and the reservoir together defining a flow path along which draining fluid flows through the conduit to the reservoir, through the microporous material, and into the tissue surrounding the eye, the flow path exhibiting variable flow resistance along the conduit, the conduit having a plurality of sequential flow resistances defined therein, the first flow resistance and the second flow resistance being optionally different from the second flow resistance.

[0007] In addition to Example 1, according to another example ("Example 2"), the shunt body has a continuous wall defining the reservoir and a reservoir opening in the continuous wall that communicates with an internal reservoir, through which the conduit engages and is received, at least a portion of the continuous wall having a wall portion made of a microporous material, the wall portion having an inner side facing the internal reservoir and an opposite outer side facing an external region of the human eye, the inner side of the wall portion optionally having a low-porosity surface extending throughout the inner side of the wall portion, and the outer side of the wall portion optionally having alternating surfaces including low-porosity surfaces disposed between high-porosity surfaces.

[0008] In addition to Example 1, according to another example ("Example 3"), the first flow resistance is less than the second flow resistance.

[0009] In addition to Example 1, according to another example ("Example 4"), the first flow resistance is greater than the second flow resistance.

[0010] In addition to Example 1, according to another example ("Example 5"), the microporous material defines a third flow resistance of the flow path.

[0011] In addition to Example 5, according to another example ("Example 6"), the microporous material is configured to transition from a hydrophobic state to a hydrophilic state when exposed to the fluid, and the second flow resistance optionally corresponds to a rate of change of pressure relative to flow rate over time when fluid engages the microporous material defining the reservoir.

[0012] In addition to Example 6, according to another example ("Example 7"), the rate of change corresponds to the density of the porosity of the microporous material.

[0013] In addition to Example 7, according to another example ("Example 8"), the microporous material has a variable porosity across the thickness of the microporous material.

[0014] In addition to Example 5, according to another example ("Example 9"), the first flow resistance corresponds to a ratio of an inner diameter of the conduit to a thickness of the conduit.

[0015] In addition to Example 1, according to another example ("Example 10"), the first flow resistance and the second flow resistance are oriented in a series configuration such that a fluid flowing through the flow path optionally encounters the first flow resistance before encountering the second flow resistance.

[0016] In addition to Example 1, according to another example ("Example 11"), the variable flow resistance along the conduit further comprises a third flow resistance.

[0017] In addition to Example 11, according to another example ("Example 12"), each of the first flow resistance and the third flow resistance is greater than the second flow resistance.

[0018] In addition to Example 11, according to another example ("Example 13"), the first flow resistance, the second flow resistance, and the third flow resistance are different from each other.

[0019] According to another example ("Example 14"), there is provided a drainage device for directing drainage fluid from inside the eye to a body part outside the eye, the drainage device including a flow path configured to facilitate drainage of fluid from inside the eye to surrounding tissue outside the eye, the flow path having a variable flow resistance to drainage fluid passing through the flow path, the flow path including a first flow resistance portion having a first flow resistance and a second flow resistance portion having a second flow resistance, the first flow resistance optionally different from the second flow resistance.

[0020] In addition to Example 14, according to another example ("Example 15"), the first flow resistance is less than the second flow resistance.

[0021] In addition to Example 14, according to another example ("Example 16"), the first flow resistance is greater than the second flow resistance.

[0022] In addition to Example 14, according to another example ("Example 17"), the flow path is located between a microporous material configured to transition from a hydrophobic state to a hydrophilic state when exposed to waste fluid, and the second flow resistance optionally corresponds to a rate of change of pressure relative to flow rate over time when the fluid engages the microporous material.

[0023] In addition to Example 17, according to another example ("Example 18"), the rate of change corresponds to the density of the porosity of the microporous material.

[0024] In addition to Example 18, according to another example ("Example 19"), the microporous material has a variable porosity across the thickness of the microporous material.

[0025] In addition to Example 14, according to another example ("Example 20"), the first flow resistance corresponds to a diameter of the flow path.

[0026] In addition to Example 14, according to another example ("Example 21"), the first flow resistance and the second flow resistance are oriented in a series configuration such that a fluid flowing through the flow path may encounter the first flow resistance before encountering the second flow resistance.

[0027] In addition to Example 14, according to another example ("Example 22"), the flow path further includes a third flow resistance portion having a third flow resistance.

[0028] In addition to Example 22, according to another example ("Example 23"), each of the first flow resistance and the third flow resistance is greater than the second flow resistance.

[0029] In addition to Example 22, according to a different example ("Example 24"), the first flow resistance, the second flow resistance, and the third flow resistance are different from each other.

[0030] According to another example ("Example 25"), a method of forming a drainage device, the method including: disposing one or more microporous materials to form a device body having a reservoir defined therein, wherein the reservoir is configured to receive and accumulate a fluid; and securing a conduit to the reservoir so that the conduit is in fluid communication with the reservoir, wherein the conduit and the reservoir define a flow path of the drainage device, the flow path having a variable flow resistance to drainage fluid passing through the flow path, the flow path having a first flow resistance portion having a first flow resistance and a second flow resistance portion having a second flow resistance, the first flow resistance optionally being different from the second flow resistance.

[0031] In addition to Example 25, according to another example ("Example 26"), forming the reservoir optionally includes securing a first portion of the microporous material to a second portion of the microporous material to form the reservoir therebetween, the method further including securing the conduit between the first and second portions, the conduit configured to receive waste fluid.

[0032] In addition to Example 26, according to another example ("Example 27"), the one or more microporous materials include a first layer having a first microporous membrane bonded to a second microporous membrane and a second layer including a third microporous membrane bonded to a fourth microporous membrane, and fixing the first portion to the second portion optionally includes bonding the second microporous membrane to the third microporous membrane.

[0033] In addition to Example 27, according to another example ("Example 28"), the second microporous membrane and the third microporous membrane are bonded to each other along the peripheral edges of the first layer and the second layer to define an expandable reservoir disposed between the second microporous membrane and the third microporous membrane, the second microporous membrane and the third microporous membrane optionally being configured to resist tissue ingrowth, the first microporous membrane and the fourth microporous membrane optionally being configured to allow tissue ingrowth, and the second microporous membrane and the third microporous membrane optionally having an expanded state maintained adjacent the peripheral edges of the first layer and the second layer.

[0034] In addition to Example 27, according to another example ("Example 29"), fixing the first portion to the second portion includes refraining from bonding the first microporous membrane to the fourth microporous membrane.

[0035] In addition to Example 27, according to another example ("Example 30"), fixing the first portion to the second portion includes arranging the first layer and the second layer in a stack configuration such that the first microporous membrane and the fourth microporous membrane are the outermost membranes of the device body, and the second microporous membrane and the third microporous membrane are the innermost membranes of the device body.

[0036] According to another example ("Example 31"), a glaucoma drainage device for draining fluid from an internal region of a human eye to an external region of the human eye includes a body having a continuous wall defining an internal reservoir within the body and a reservoir opening in the continuous wall that communicates with the internal reservoir, and a conduit extending from the body a conduit length, the conduit having opposing first and second conduit ends defining a passageway therethrough extending between the first and second opposing conduit ends, the first conduit end engaging the internal reservoir opening to extend beyond the second conduit end. and the internal reservoir, the length of the conduit is sufficient to position the first conduit end in an external region of the human eye and the second conduit end in an internal region of the human eye, at least a portion of the continuous wall optionally having a wall portion made of a microporous material, the wall portion having an inner side facing the internal reservoir and an opposite outer side facing the external region of the human eye, the inner side of the wall portion optionally having a low-porosity surface extending across the entire inner side of the wall portion, and the outer side of the wall portion optionally having alternating surfaces including low-porosity surfaces disposed between high-porosity surfaces.

[0037] In addition to Example 31, according to another example ("Example 32"), the wall portion defines a wall portion thickness extending between the inner side and the outer side, the wall portion thickness optionally defining an interior region of the wall portion having a transitional porosity between the porosity of the inner, low-porosity surface and the porosity of the outer, high-porosity surface.

[0038] In addition to Example 31, according to another example ("Example 33"), the wall portion defines a wall portion thickness extending between the inner side and the outer side, and the wall portion thickness optionally defines a wall portion interior region extending between the inner low-porosity surface and the outer low-porosity surface, and the interior region optionally has an interior region porosity equal to the porosity of the inner and outer low-porosity surfaces.

[0039] In addition to Example 31, according to another example ("Example 34"), the wall portion defines a wall portion thickness extending between the inner side and the outer side, the wall portion thickness optionally defining an interior region of the wall portion extending between the inner low-porosity surface and the outer high-porosity surface, the interior region optionally having an interior region porosity equal to the porosity of the inner low-porosity surface.

[0040] In addition to Example 31, according to another example ("Example 35"), the wall portion defines a wall portion thickness extending between the inner side and the outer side, the wall portion thickness optionally defining an interior region of the wall portion extending between the inner low-porosity surface and the outer high-porosity surface, the interior region optionally having an interior region porosity equal to the porosity of the outer high-porosity surface.

[0041] In addition to Example 31, according to another example ("Example 36"), the fluid connection between the second conduit end and the internal reservoir extends further from the internal reservoir through the microporous material, optionally providing fluid communication from the internal reservoir to an external region of the human eye.

[0042] In addition to Example 36, according to another example ("Example 37"), the fluid communication defines a flow path through the microporous material.

[0043] In addition to Example 37, according to another example ("Example 38"), the flow path through the microporous material is in a direction away from the internal reservoir.

[0044] In addition to Example 37, according to another example ("Example 39"), the flow path through the microporous material proceeds from a low porosity microporous region to a high porosity microporous region.

[0045] The foregoing examples are merely illustrative and should not be construed as limiting or narrowing the scope of the inventive concepts otherwise provided by this disclosure. While multiple examples are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative examples. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive. [Brief explanation of the drawings]

[0046] BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification, illustrate embodiments and, together with the description, serve to explain the principles of the disclosure.

[0047] [Figure 1A] FIG. 1A is a diagram of an eye having an implanted drainage system consistent with various aspects of the present disclosure.

[0048] [Figure 1B] FIG. 1B is a cross-sectional view of detail A1 of FIG. 1A.

[0049] [Figure 1C] FIG. 1C is a schematic diagram of the implanted drainage device in detail A2 of FIG. 1B.

[0050] [Figure 2A] FIG. 2A is a side view of a drainage system in the form of a glaucoma shunt consistent with various aspects of the present disclosure.

[0051] [Figure 2B] FIG. 2B is a bottom view of the drainage system of FIG. 2A.

[0052] [Figure 2C] FIG. 2C is a cross-sectional view of the drainage system of FIG. 2A taken at section BB of the drainage system in a contracted state and with a conjunctival tab.

[0053] [Figure 2D] FIG. 2D is a cross-sectional view of the drainage system 100 of FIG. 2A taken at section CC of the drainage system in a contracted state and having first and second layers with different microstructures and thicknesses.

[0054] [Figure 2E] FIG. 2E is a perspective view of an alternative, compact embodiment of the drainage system 100 of FIG. 2A.

[0055] [Figure 3A] FIG. 3A is a schematic diagram of the wall of a drainage device in a contracted state.

[0056] [Figure 3B] FIG. 3B is a schematic illustration of the wall of the drainage device in an inflated state.

[0057] [Figure 3C] FIG. 3C is an SEM image of a portion of the microstructure shown schematically in the drainage system of FIGS. 3A and 3B, the SEM image scaled as shown.

[0058] [Figure 4A] FIG. 4B shows various configurations of the drainage device that may have undergone a modification process to provide various degrees of resistance. [Figure 4B] FIG. 4B shows various configurations of the drainage device that may have undergone a modification process to provide various degrees of resistance. [Figure 4C] FIG. 4C shows various configurations of the drainage device that may have undergone a modification process to provide various degrees of resistance. [Figure 4D] FIG. 4D shows various configurations of the drainage device that may have undergone a modification process to provide various degrees of resistance.

[0059] [Figure 4E] FIG. 4E is a bar graph comparing the measured pressure values ​​associated with the components of FIGS. 4A-4D and the effect of various modifications to these components.

[0060] [Figure 5A] FIG. 5A is a flowchart of a manufacturing method consistent with various aspects of the present disclosure.

[0061] [Figure 5B] FIG. 5B is a flowchart of a method of use consistent with various aspects of the present disclosure; and

[0062] [Figure 6A] FIG. 6A is a schematic side view of a sessile drop test performed on a surface to determine hydrophobicity / hydrophilicity. [Figure 6B] FIG. 6B is a schematic side view of a sessile drop test performed on a surface to determine hydrophobicity / hydrophilicity. DETAILED DESCRIPTION OF THE INVENTION

[0063] Detailed Description Definitions and Terminology This disclosure is not intended to be read in a limiting sense, for example, the terms used in this application should be read broadly in the context of the meanings ascribed to such terms by experts in the field.

[0064] With respect to the term imprecision, the terms "about" and "approximately" may be used interchangeably to refer to a stated measurement, including measurements that are reasonably close to the stated measurement. A measurement that is reasonably close to the stated measurement deviates from the stated measurement by a reasonably small amount, as understood and easily ascertained by one of ordinary skill in the relevant art. Such deviations may result from measurement error, differences in calibration of measuring and / or manufacturing equipment, human error in reading and / or setting measurements, fine-tuning made to optimize performance and / or structural parameters given differences in measurements associated with other components, specific implementation scenarios, imprecise adjustment and / or manipulation of the object by a human or machine, and the like. If it is determined that the value of such a reasonably small difference would not be easily ascertainable by one of ordinary skill in the relevant art, the terms "about" and "approximately" may be understood to mean plus or minus 10% of the stated value.

[0065] Description of Various Embodiments Those skilled in the art will readily appreciate that the various aspects of the present disclosure may be implemented by any number of methods and apparatus configured to perform the intended functions. It should also be noted that the accompanying drawings referred to herein are not necessarily drawn to scale and may be exaggerated to illustrate various aspects of the present disclosure, and in that regard, the drawings should not be construed as limiting.

[0066] Various features of the devices, systems, and methods disclosed herein can be seen in FIGS. 1A-1C. Aspects of the present disclosure relate to drainage devices, systems, and methods for fluids, including, but not limited to, bodily fluids. More specifically, the present disclosure relates to devices, systems, and methods for draining aqueous humor from the anterior chamber "AC" of a patient's eye 10 so that the aqueous humor can be absorbed elsewhere in the body. To that end, FIG. 1A is a diagram of the eye 10, including the subconjunctival space 11 between the conjunctiva 13 and the sclera 15 of the eye 10. A drainage system 100 according to the principles of the present disclosure has been implanted within the eye 10. FIG. 1B shows a cross-sectional view of detail A1 of FIG. 1A. FIG. 1C shows a schematic diagram of the implanted drainage device 110 at detail A2 of FIG. 1B. In one aspect of the present disclosure, a mechanism is provided for reabsorbing aqueous humor drained from the anterior chamber "AC" of the eye 10 to reduce or otherwise stabilize intraocular pressure. However, those skilled in the art will appreciate that aspects of the present disclosure are also useful in other applications where it is desirable to redirect waste fluid within the body.

[0067] The drainage system 100 shown in FIGS. 1A-1C includes a drainage device 110 for treating glaucoma. As shown herein, the glaucoma drainage device 110 has a wall 112 (best seen in FIGS. 1B and 1C ) having a first side 114 and a second side 116. While described below with reference to an aspiration conduit 120, it should be understood that the drainage device 110 can be a stand-alone product and, therefore, should not be considered outside the scope of the present disclosure, so long as a portion of the drainage device 110 is configured to receive fluid (e.g., directly from an incision, from a fluid conduit 120, etc.). The drainage device 110 can be fluidly coupled to the aspiration conduit 120. When implanted, the aspiration conduit 120 extends from the anterior chamber "AC" of the eye 10 to the drainage device 110. Aqueous humor from the anterior chamber "AC" then flows through the aspiration conduit 120 and into the drainage device 110.

[0068] The material selection for the drainage device 110 can contribute to its functionality and relative low profile compared to other devices known in the art. The drainage device 110 can comprise biocompatible materials, including microporous materials such as expanded polytetrafluoroethylene (ePTFE), as described below. The aspiration conduit 120 can be flexible and comprise biocompatible materials suitable for use in constructing elongate members. Some such suitable materials include silicone, polytetrafluoroethylene, polypropylene, polymethyl methacrylate, acrylic, polyurethane, silastic, and metal. Such a construction of the drainage system 100 is particularly useful for surgical implant procedures.

[0069] Generally, surgical implantation of a drainage device, such as drainage system 100, carries the risk of creating abnormal pressure within eye 10. For example, when a drainage device is surgically implanted beneath the outer surface tissue (i.e., conjunctiva 13) of eye 10 (as indicated by the dotted line around device 110), such as in a procedure requiring the formation of a bleb, the surrounding tissue fresh from the surgical injury does not provide appreciable flow resistance to aqueous humor flow until sufficient wound healing has occurred. During this initial post-operative period, the patient is at risk for hypotony (e.g., too low an intraocular pressure) in eye 10. To avoid hypotony, measures are taken to manage flow through drainage device 110 for a period of time. For example, surgeons traditionally "knot" a portion of suction conduit 120 near its proximal end for a period of time, then release the knot after sufficient surgical wound healing has progressed to allow the surrounding tissue to provide the necessary flow resistance. In certain commercially available glaucoma shunt devices, a flow-restricting "valve" is added distal to the aspiration conduit 120 where the plate section is located. However, these devices are relatively stiff and bulky and can still cause hypotony. Conversely, drainage devices, systems, and methods according to the principles of the present disclosure advantageously include low-profile devices that create appreciable flow resistance early after surgery, e.g., to avoid hypotony.

[0070] 1B and 1C, a non-limiting example implantation procedure of the drainage system 100 is shown. In this example, the drainage system 100 is shown positioned in the subconjunctival space 11 between the conjunctiva 13 and the sclera 15 of the eye 10. The drainage system 100 is shown oriented such that the first layer 114 extends along the sclera 15 and the second layer 116 extends along the conjunctiva 13. It will be appreciated that, as discussed below, the portion of the second layer 116 that interfaces with the conjunctiva 13 can be configured to promote or allow tissue ingrowth. It will also be appreciated that, as discussed below, the portion of the first layer 114 that interfaces with the sclera 15 can additionally or alternatively be configured to promote or allow tissue ingrowth. Such a configuration helps minimize relative movement between the drainage device 110 and the surrounding tissue.

[0071] 1B and 1C show an aspiration conduit 120 extending from the drainage device 110 and through a scleral access, perforation, or hole "H" (e.g., formed by a physician during implantation using known methods) such that a first end 122 (e.g., proximal end) accesses the anterior chamber "AC" and places a port 271 in communication with the anterior chamber "AC." In some embodiments, upon implantation, aqueous humor enters the first end 122 of the aspiration conduit 120 and travels to a second end 124 (e.g., distal end) of the aspiration conduit 120, which is in fluid communication with the drainage device 110. Together, the wall 112 and the aspiration conduit 120 can define a flow path 140 through which drainage fluid flows through the drainage device 110. In some embodiments, the second end 124 is positioned within the drainage device 110 so that the discharged aqueous humor enters a reservoir 130 defined within the drainage device 110 and penetrates through various diffusion membranes of the drainage device 110, where it can then be absorbed by surrounding tissue and / or ingrown tissue.

[0072] 2A-2E, various aspects of an exemplary drainage system 100 in the form of a glaucoma shunt 110 are shown. FIG. 2A shows a side view of the drainage system 100. FIG. 2B shows a bottom view of the drainage system 100 of FIG. 2A. FIG. 2C shows a cross-sectional view of the drainage system 100 of FIG. 2A taken at section BB of the drainage system 100 in a contracted state. This drainage system 100 shows a conjunctival tab that prevents erosion of the conjunctiva 13 by the conduit 120, a neck where the conduit 120 is coupled to the wall 112 (e.g., via adhesive "b"), and a reservoir 130 at the distal end of the conduit 120. FIG. 2D shows a cross-sectional view of the drainage system 100 of FIG. 2A taken at section CC of the drainage system 100 in a contracted state. FIG. 2E shows a perspective view of an alternative, smaller embodiment of the drainage system 100 of FIG. 2A. Here, as in FIGS. 1A-1C, the drainage system 100 is directed to draining fluid from one portion of a patient's body to another. In particular, the conduit 120 can be inserted into the reservoir 130 to a variable depth, such as a shallow depth as shown in FIG. 2C or a deep depth as shown in FIG. 2D, as long as fluid can escape the distal end 124 of the conduit 120 and fill the reservoir 130. Such a device can have a low-profile configuration with fluid flow resistance that can be assessed early after surgery to avoid hypotony.

[0073] As a glaucoma shunt 110, the drainage system 100 shown in these figures is useful for draining fluid from the eye. This drainage can proceed from the interior of the eye (e.g., the anterior chamber) to surrounding tissues outside the eye. The drainage device 110 can include a wall 112 defining a reservoir 130 disposed within the wall 112. The reservoir 130 can be configured to be in fluid communication with the eye to receive drainage fluid from the interior of the eye into the reservoir 130. The wall 112 can be integrated into or entirely form the body of the drainage device 110. In this regard, the body can have the wall 112 defining the internal reservoir 130 within the body and an internal reservoir opening disposed within the wall 112 (e.g., at or around adhesive "b" in FIG. 2C ) that can be in communication with the internal reservoir 130. As often described herein, the wall 112 is continuous (eg, a continuous wall 112), although other types of wall 110 having sealed discontinuities are also contemplated.

[0074] The wall 112 can include a microporous material that transitions from a hydrophobic state to a hydrophilic state. In examples, the wall 112 is configured to provide a variable flow resistance as the wall 112 transitions from a hydrophobic state to a hydrophilic state. The drainage device 110 can include a flow channel 140 configured to facilitate drainage of fluid from the interior of the eye to surrounding tissue outside the eye. In particular, the flow channel 140 can provide a variable flow resistance to drainage through the flow channel 140. The flow channel 140 can have a first flow resistance portion having a first flow resistance and a second flow resistance portion having a second flow resistance. In some cases, the first flow resistance can be different from the second flow resistance, as described in more detail below.

[0075] Wall 112 can be a multilayer structure including one or more microstructures. Wall 112 can also be a continuous monolayer structure that can include multiple sublayers within a continuous monolayer structure or define opposing sides of a continuous monolayer structure that exhibit one porosity on a first side and a second porosity on a second side of the monolayer structure. In this regard, an example of wall 112 can include a first layer 114 having a first microporous membrane 241 engaged with a second microporous membrane 242, and a second layer 116 including a third microporous membrane 243 engaged with a fourth microporous membrane 244. In many instances, the engagement between the first and second microporous membranes 241, 242 and the third and fourth microporous membranes 243, 244 is such that the first and second microporous membranes 241, 242 and the third and fourth microporous membranes 243, 244, respectively, are integrally formed with one another. In certain instances, the first layer 114 and the second layer 116 can include more or fewer microporous membranes, some of which configurations are discussed in U.S. patent application Ser. No. 15 / 922,692, entitled "Integrated Aqueous Shunt for Treating Glaucoma," filed March 15, 2018, the entire contents of which are incorporated herein by reference.

[0076] The presence of various microporous materials within the continuous single-layer structure can facilitate operation of the reservoir 130. As fluid enters the reservoir 130, it can engage with the microporous material of the wall 112. Under certain circumstances, the second and third microporous membranes 242, 243 are engaged with one another along the peripheral edge 247 of the drainage device 110. For example, the second and third microporous membranes 242, 243 can engage around the periphery of the first and second layers 114, 116 to define a reservoir disposed between the second and third membranes 114, 242, 243. This engagement can be, for example, a hermetic seal bond to ensure the structural integrity of the reservoir 130. In certain instances, the second and third microporous membranes 242, 243 can initially be in contact or proximity with one another such that fluid can engage the interface between the second and third microporous membranes 242, 243 to initially inflate the reservoir 130. In this regard, initially and subsequently, the reservoir 130 can be configured to move between a contracted state in which the second and third microporous membranes 242, 243 resist fluid flow therebetween, and an expanded state in which fluid can flow between the second and third microporous membranes 242, 243. In certain instances, the first and fourth microporous membranes 241, 244 can remain unattached to one another, although in other cases it can be useful to have them engaged with one another (e.g., similar to the engagement of the second and third microporous membranes 242, 243).

[0077] The arrangement of the microporous material to form the wall 112 can be such that wetting of the microporous material is promoted on the outer side 253 of the wall 112 before on the inner side 251 of the wall 112. In this regard, the inner side 251 of the wall 112 can form the reservoir 130. In an example, the first layer 114 and the second layer 116 are in a stacked configuration such that the first microporous membrane 241 and the fourth microporous membrane 244 are the outermost membranes of the wall 112, and the second microporous membrane 242 and the third microporous membrane 243 are the innermost membranes of the wall 112.

[0078] In examples, the microporous material can include ePTFE. In this regard, the microporous material can be configured to transition from a hydrophobic state to a hydrophilic state upon wetting of the microporous material by a fluid, with the microporous material configured such that wetting of the outer portion of the wall 112 occurs before wetting of the surfaces defining the reservoirs 130. In examples, the hydrophilic state promotes tissue ingrowth. In some such examples, the hydrophilic state can define a first side of the microporous material, and the hydrophobic state can define a second side of the microporous material. Additionally, other materials similar to ePTFE are contemplated. These other materials can include polymers such as, but not limited to, polyethylene, polyurethane, polysulfone, polyvinylidene fluoride (PVDF), polyhexafluoropropylene (PHFP), perfluoroalkoxy polymers (PFA), polyolefins, fluorinated ethylene propylene (FEP), acrylic copolymers, and other suitable fluorocopolymers.

[0079] Drainage fluid from the interior of the eye can flow through the drainage device 110 via the channels 140, as illustrated in FIGS. 1C and 2D , although other figures defining reservoirs and / or tubes also show fluids that can pass through the device. The channels 140 can include a portion (e.g., part or all) of the wall 112 and, optionally, the aspiration conduit 120, as described in more detail below. In this regard, in one example, fluid can flow into and then out of the reservoir 130 via the channels 140 after being received by the wall 112 via the aspiration conduit 120 or directly. For example, in a first example where the reservoir 130 is filled with fluid, the reservoir 130 can gradually move from a deflated state toward an expanded state. The fluid can then remain in the reservoir 130 until the portion of the wall 112 transitions from a hydrophobic state to a hydrophilic state. In such cases, bodily fluids may penetrate the wall 112 (eg, from the inside 251 of the wall 112 to either the outside 253 or periphery of the wall 112) and be diverted by the wall 112 to surrounding areas of the body.

[0080] In embodiments where bonding is used in part or in whole to secure the membranes to one another, bonding of the microporous materials can occur at the peripheries 261, 262, 263, 264 of the microporous membranes 241, 242, 243, 244 within the drainage device 110. In particular, the first microporous membrane 241 is shown with a first periphery 261, the second microporous membrane 242 is shown with a second periphery 262, the third microporous membrane 243 is shown with a third periphery 263, and the fourth microporous membrane 244 is shown with a third periphery 264. As alluded to above, any combination of these microporous membranes 241, 242, 243, 244 can be bonded at their respective peripheries 261, 262, 263, 264. For example, the second and third microporous membranes 242, 243 are bonded at their peripheral edges 262, 263 to form the reservoir 130 between the second and third microporous membranes 242, 243. In some such instances, the first and fourth microporous membranes 241, 244 are free from the second and third peripheral edges 262, 263 of the second and third microporous membranes 242, 243, respectively. In some such instances, the first and fourth microporous membranes 241, 244 are partially or wholly free from one another. In any of these examples, the bonds at the peripheral edges 261, 262, 263, 264 of the microporous membranes 241, 242, 243, 244 can be sealed bonds, optionally accommodating additional structures such as the aspiration conduit 120 and sealingly bonding them to the drainage device 110. In alternative embodiments similar to those described above, bonds can be applied as described above except between the first membrane 241 and the second membrane 242, which can be replaced with a single unitary layer comprising sublayers having the properties of the first and second membranes, and between the third and fourth membranes 243 and 244, which can likewise be replaced with a single unitary layer comprising sublayers having the properties of the third and fourth membranes.

[0081] Notably, at least a portion of the continuous wall 112 can have a wall portion (e.g., part or all of the wall 112) comprised of a microporous material. The wall portion can have an inner wall portion 251 facing the internal reservoir 130 and an outer wall portion 253 opposite the inner wall portion 251 and facing the external region of the human eye. The inner wall portion 251 can have a low-porosity surface extending across the inner wall portion 251. The outer wall portion 253 can have alternating surfaces including low-porosity surfaces disposed between high-porosity surfaces.

[0082] The conduit 120 can be positioned to extend a conduit length from the body. The conduit 120 can have opposing first and second conduit ends 122, 124 that define a passageway through the conduit 120, such that the passageway can extend between the opposing first and second conduit ends 122, 124. The first conduit end 122 can engage an internal reservoir opening and provide a fluid connection between the second conduit end 124 and the internal reservoir 130. The conduit length can be sufficient to position the first conduit end 122 in an external region of the human eye and the second conduit end 124 in an internal region of the human eye. In an example, the fluid connection between the second conduit end 124 and the internal reservoir 130 further extends from the internal reservoir 130 through a microporous material, providing fluid communication from the internal reservoir 130 to the external region of the human eye. This fluid communication can define a flow path through the microporous material. As described further below, the flow path through the microporous material can be in a direction away from the internal reservoir 130 and / or from a low-porosity microporous region to a high-porosity microporous region.

[0083] Various features of another example drainage system 100 consistent with various aspects of the present disclosure are shown in FIG. 2E. In particular, similar to other drainage devices 100 discussed elsewhere herein, FIG. 2E illustrates a drainage system 100 having a wall 112 with a reservoir 130 defined therein and an aspiration conduit 120 in fluid communication with the reservoir 130. As with FIGS. 1A-1C and 2A-2D, the drainage system 100 is directed to draining fluid from one portion of a patient's body to another. Such a device can have a low-profile configuration with fluid flow resistance assessable early postoperatively to avoid hypotony. Due to its smaller size (e.g., in one or more dimensions including length, width, and thickness), this device 110 is more suitable for smaller patients than the device 110 of FIGS. 2A-2D. In some examples, the thickness of the device 110 (i.e., the maximum thickness of the shunt or shunt body 110) is between about 25 μm and about 30 μm, between about 30 μm and about 40 μm, between about 40 μm and about 50 μm, between about 50 μm and about 60 μm, between about 60 μm and about 70 μm, between about 70 μm and about 80 μm, between about 80 μm and about 90 μm, between about 90 μm and about 100 μm, between about 10 μm and about It can be 150 μm, about 150 μm to about 200 μm, about 200 μm to about 250 μm, about 250 μm to about 300 μm, about 300 μm to about 350 μm, about 350 μm to about 400 μm, about 400 μm to about 450 μm, about 450 μm to about 500 μm, or any other suitable value or range therebetween, and / or a combination of these ranges.

[0084] The drainage system 100 shown here is similar in many respects to the drainage systems discussed above. For example, the drainage system 100 shown here can include first and second layers, as described with respect to FIGS. 2A-2D. These layers are bonded (e.g., with second and third microporous membranes) around an aspiration conduit 120 similar to that described with respect to FIGS. 1A-1C. While shown extending to a particular location, the distal end of the aspiration conduit 120 can be positioned to communicate with the reservoir 130 (e.g., more proximally or distally than shown, suspended between the reservoirs 130, or positioned along the interior of the reservoirs 130). Other variations will be apparent to those skilled in the art.

[0085] As described above, drainage from the interior of the eye to the reservoir 130 can be facilitated by forming a flow path therebetween. An exemplary medium for forming such a flow path is via the aspiration conduit 120. The aspiration conduit 120 can be an elongated, flexible, hollow member, such as a shunt. The aspiration conduit 120 can be in fluid communication with the reservoir 130 and optionally disposed in sealing engagement with the reservoir 130. In this regard, the aspiration conduit 120 can have a second end in communication with the reservoir 130 and an opposing first end defining a port. Thus, the first end can be a proximal end of the aspiration conduit 120, and the second end can be a distal end of the aspiration conduit 120. The aspiration conduit 120 can be configured to be disposed within the eye to facilitate drainage from the interior of the eye through the port to the reservoir 130.

[0086] Additional configurations of drainage devices with variable resistance are described in detail, along with additional explanations, in U.S. Provisional Application No. 63 / 276,170, entitled "BIOLOGICAL FLUID DRAINAGE DEVICES, SYSTEMS, AND METHOD," filed November 5, 2021, and U.S. Application No. 17 / 980,417, entitled "Fluid DRAINAGE DEVICES, SYSTEMS, AND METHOD," filed November 3, 2022, the entire disclosures of each of which are incorporated herein by reference in their entirety.

[0087] Further details of the microporous material are described herein with reference to Figures 3A-3C. For clarity, these figures omit the illustration of conduits, although it is understood that conduits can be placed in fluid communication with the reservoir 130, as described elsewhere herein. In particular, Figures 3A and 3B show cross-sectional views of the wall 112 of the drainage system, taken along the center portion of the width of the drainage system, with the reservoir 130 disposed therein. More specifically, Figure 3A shows the drainage device in a contracted state (with little or no fluid in the reservoir 130). Figure 3B shows the drainage device in an expanded state (with fluid collecting in the reservoir 130 to expand it). Figure 3C is an enlarged view of the microstructures in the drainage system of Figures 3A and 3B. Displayed at the bottom of Figure 3C is "5.00kV 4.2mm x500 SE 1 / 23 / 2018" and the distance between two consecutive lines as shown in the bottom right corner is 10µm.

[0088] 3A and 3B, the fluid-permeable microstructure can be contained within a portion (e.g., part or all) of the microporous material. The microstructure can include multiple deposits of microporous membranes therein, such that the microporous material is a multi-membrane material. Grouped or coupled deposits of microporous membranes can form layers of the microporous material, which can be overlapped, folded, or similarly arranged. Under these circumstances, the reservoir 130 can be formed with a reservoir proximal section 231 and a reservoir distal section 232, allowing collected fluid to diffuse to surrounding tissue outside the wall 112.

[0089] Expansion of the reservoir 130 can occur at the unbonded portions of the wall 112. As described above, the second and third microporous membranes 242, 243 can be bonded around their peripheries such that their interior portions are unbonded. Because these portions are unbonded, they are free to separate from each other (or one from the other), allowing the reservoir 130 to fill with fluid. The reservoir 130 can have a reservoir proximal section 231, which can be positioned adjacent to the distal end of the inlet conduit, and a reservoir distal section 232, which can be positioned opposite the reservoir proximal section 231, as described further below. Fluid flow entering (or within) the reservoir 130 can be directed from the distal end of the inlet conduit toward the periphery of the chamber. In this regard, the reservoir proximal section 231 can be configured to expand before the reservoir distal section 232.

[0090] The engagement of the fluid with the microporous material can provide flow resistance, resulting in pressure within the reservoir 130. For example, the second and third microporous membranes 242, 243 of the wall 112 can be positioned adjacent to each other and, in some cases, can contact each other. As the reservoir 130 fills, the second and third microporous membranes 242, 243 can be gradually pulled apart by fluid entering the reservoir 130. For example, the inner surface of the reservoir 130 can initially be hydrophobic, so that flow into the reservoir 130 increases pressure, thereby forcing the reservoir 130 to expand (e.g., forcing the second and third chambers apart). As the wall 112 transitions from a hydrophobic state to a hydrophilic state and the fluid flow engages the reservoir 130, a variable flow resistance can be provided to the fluid flow. The variable flow resistance can correspond to a rate of change of pressure relative to flow rate over time. In the example, the wall 112 transitions from a hydrophobic state having a first flow resistance, to a partially hydrophilic state having a second flow resistance, to a hydrophilic state having a third flow resistance, where the first flow resistance is greater than both the second flow resistance and the third flow resistance, and the second flow resistance is greater than the first flow resistance.

[0091] The rate of diffusion of fluid from the reservoir 130 through the wall 112 can be affected by the flow rate and increases as flow resistance decreases. As the reservoir 130 expands and the microporous material transitions from a hydrophobic state to a hydrophilic state, this diffusion can occur in many directions (e.g., radially outward from the reservoir 130, through unbonded portions of the periphery, etc.). When inflow into the reservoir 130 is less than outflow from the reservoir 130, the reservoir 130 can move from an expanded state toward a deflated state. Conversely, when inflow into the reservoir 130 is greater than outflow from the reservoir 130, the reservoir 130 can move from a deflated state toward an expanded state. Assuming continuous flow into the reservoir 130, the reservoir 130 can remain in an expanded state, an intermediate state between the expanded and deflated states. In any of these examples, there is a pressure associated with the flow rate and / or fill level of the reservoir 130. After collection of fluid in reservoir 130, the fluid can diffuse via osmosis through wall 112 at different rates depending on the transition state of the microporous material.

[0092] The permeability of each layer of microporous material may vary across the dimensions (e.g., thickness or length) of the microstructures therein. Under these circumstances, in certain examples, the first microporous membrane 241 permeability may be higher than the second microporous membrane 242 permeability. Similarly, the fourth microporous membrane 244 permeability may be higher than the third microporous membrane 243 permeability. In examples, the second microporous membrane 242 permeability may be approximately the same as the third microporous membrane 243 permeability. In examples, the first microporous membrane 241 permeability may be approximately the same as the fourth microporous membrane 244 permeability. In some such instances, the second microporous membrane 242 permeability and the third microporous membrane 243 permeability are different from the first microporous membrane 241 permeability and the fourth microporous membrane 244 permeability, respectively.

[0093] The porosity of the membrane within the microporous material can be configured to affect the tissue ingrowth capability in that portion. It may be desirable for tissue ingrowth to occur in some portions of the wall 112 (e.g., the exterior 253 of the wall 112) and be resisted in other portions of the wall 112 (e.g., the reservoir 130). Tissue ingrowth in the exterior 253 of the wall 112 can secure the device in its implanted position, and resisting ingrowth in the reservoir 130 can prevent tissue growth throughout the reservoir 130 from rendering it inexpandable. To accomplish this function, the porosity of one side of the microporous material can be greater than the porosity of another, opposing side of the microporous material. In this regard, the microporous material can have a dense side (e.g., greater porosity) and an open side (e.g., less porosity). In an example, the second and third microporous membranes 242, 243 can be configured to resist tissue ingrowth. In some examples, the first and fourth microporous membranes 241, 244 are configured to allow tissue ingrowth, and the second and third microporous membranes 242, 243 have an expanded state that is maintained adjacent to the joined peripheral edges of the first and second layers 114, 116.

[0094] The microstructural perforations allow fluid to penetrate the microporous material. These perforations can vary in size, for example, based on the function of a given microporous membrane. In an example, either or both of the first and fourth microporous membranes 241, 244 can include perforations of a range of sizes (or average sizes) that allow ingrowth of blood vessels and other tissue. In a further example, either or both of the second and third microporous membranes 242, 243 are configured or selected so that the perforations therein are generally sized to minimize, resist, or prevent tissue ingrowth and attachment while maintaining aqueous humor permeability.

[0095] The interior portion of the microporous material can have a variety of porosities, as seen in FIG. 3C . The interior portion can extend between the interior wall 251 and the exterior wall 253. In any of these portions of the wall, the porosity can range relatively from low porosity (LP), medium-low porosity (MLP), medium porosity (MP), medium-high porosity (MHP), and high porosity (HP). For purposes of discussion herein, assuming that drainage fluid travels along a relatively straight path through the microporous material, sequentially engaging the porosity of the interior wall portion 251, the uniform interior portion, and the exterior wall portion 253, the resultant flow resistance can be expressed by combining the respective porosities. For example, the interior wall portion 251 typically has low porosity throughout (e.g., to resist tissue ingrowth into the reservoir 130), while the interior portion and the exterior wall portion 253 can have the aforementioned degrees of porosity. Under these circumstances, the flow path through the microporous material from the reservoir 130 to the tissue surrounding the device can be described as LP-MP-HP when the interior portion has a moderate porosity, e.g., when the interior portion has a moderate porosity and the exterior 253 of the wall portion has a high porosity. Further examples are described below.

[0096] Various flow paths can exist within the microporous material. Relatively linear flow paths can include, for example, regions LP1-LP4-LP5 or LP3-MHP1-MP1-MLP1. Under some conditions, such as when high pressure is present in reservoir 130, at least a portion of the flow can proceed through the most direct path through the microporous material, such as LP1-LP4-LP5 or LP2-HP1-HP2. While some flow paths can be relatively linear, non-linear flow paths also exist. For example, under certain conditions, at least a portion of the flow can continue through regions of increasingly lower resistance, such as LP1-HP1-HP2 or LP3-MHP1-HP1-HP2. As will be appreciated, the microstructure of the microporous material can undergo a modification process to achieve a particular type of flow through the microstructure. For example, the microstructure can have a relatively uniform layer throughout the microstructure, or, as shown here, can have variable portions throughout the thickness of the microporous material.

[0097] In examples, the wall portion defines a wall portion thickness extending between the wall portion inner side 251 and the wall portion outer side 253. The wall portion thickness can define an interior region of the wall portion having a transitional porosity that is between the porosity of the low-porosity surface 251 of the wall portion inner side 251 and the porosity of the high-porosity surface of the wall portion outer side 253. Additionally or alternatively, the interior region can have an interior region porosity equal to the porosity of the inner and outer low-porosity surfaces. Additionally or alternatively, the interior region can have an interior region porosity equal to the porosity of the inner low-porosity surface. Additionally or alternatively, the interior region can have an interior region porosity equal to the porosity of the outer high-porosity surface.

[0098] Figures 4A - 4E show various configurations of a drainage device with different modifications to achieve a specific flow resistance along the flow path provided by wall 112 and conduit 120. In particular, four configurations (Figs. 4A, 4B, 4C, and 4D) are shown, where the density of the microporous material within wall 112 (as indicated by the distance between consecutive x - marks along inner side 251) and / or the inner diameter of conduit 120 (diameter D1 or D2 depending on the configuration) is altered. For example, the configuration of Fig. 4A can be considered a basic configuration where the microporous material within wall 112 has a nominal porosity and the diameter of conduit 120 is the nominal diameter D1. Compared to the configuration of Fig. 4A, the configuration of Fig. 4B has a similar density but shows that the inner diameter D2 of conduit 120 is smaller (by definition, D2 < D1), which can increase the flow resistance there. Compared to the configuration of Fig. 4A, the configuration of Fig. 4C has a denser porosity (the x - marks are placed closer to each other along inner side 251 of wall 112) but shows a similar inner diameter (D2). The configuration of Fig. 4D shows a porosity as dense as that of Fig. 4C but shows that the nominal inner diameter D1 is the same as that of Fig. 4A. The configurations of Figs. 4A - 4D also show "resistors" R1 (for conduit 120) and R2 (for wall 112), and Fig. 4E shows how the pressure along the flow path can change by varying R1 and R2 at various points. For example, in the configuration as currently described, decreasing the inner diameter from D1 to D2 can increase the pressure by +6.9 mmHg (from Fig. 4A to Fig. 4B), increasing the density of inner side 251 of wall 112 can increase the pressure by +91.8 mmHg (from Fig. 4B to Fig. 4C), and increasing the inner diameter from D2 to D1 while maintaining the density can decrease the pressure by -8.3 mmHg (from Fig. 4C to Fig. 4D).

[0099] The pressure along the flow path can be measured at the first end (proximal end) 122 where the fluid enters the inlet conduit 120, as indicated by the bold arrow labeled "flow direction." Additionally, the fluid enters the reservoir 130 and exits the device through the outside 253 of the wall 112, as indicated by the bold curved arrow. In some instances, when the denseness of the inside 251 is modified, the denseness of the outside 253 can remain the same. In some instances, the effect of modifying the denseness of the outside 253 can be negligible or minimal compared to the effect of modifying the denseness of the inside 251 of the wall 112.

[0100] Modifications to the microporous material and / or the conduit 120 can be used to tailor the overall flow resistance of the drainage device. While any number of resistances may be provided along the flow path, for simplicity, the examples disclosed herein include two or three resistance sections, and the principles can be extrapolated to cover any number of resistances in a drainage device. Starting with a drainage device 110 having at least two flow resistances, the first and second flow resistances can be oriented in a series configuration such that fluid flowing through the flow path encounters the first flow resistance before encountering the second flow resistance. In an example, the first flow resistance corresponds to the diameter of the flow path. In this regard, the inner and / or outer diameter of the conduit 120 can define the first flow resistance. In an example, the flow path extends through a microporous material (e.g., from the conduit 120, if present) configured to transition from a hydrophobic state to a hydrophilic state when exposed to drainage, such as when the reservoir is in an initial, unexpanded state. Under these circumstances, the second flow resistance can correspond to the rate of change of pressure versus flow rate over time as the fluid engages the microporous material. In some instances, the microporous material has variable porosity across the thickness of the microporous material. In some instances, the rate of change corresponds to the density of the porosity of the microporous material.

[0101] Examples of combinations of flow resistances along a flow path are now described. A waste fluid flowing through a flow path may encounter multiple flow resistances defined within the flow path. For each flow resistance in the multiple flow resistances in various components or portions of components, the magnitude of each such flow resistance may vary along the length of the flow path.

[0102] For example, for purposes of explanation, the first flow resistance and the second flow resistance can be said to be oriented in a serial configuration considering the configurations of FIGS. 4A-4D . In this regard, fluid flow through the flow path can encounter a first flow resistance (e.g., "R1") before encountering a second flow resistance (e.g., "R2"). Note that in some instances, R1 and R2 can represent a single component in the drainage system 100 (e.g., the aspiration conduit 120 or the drainage device 110) or multiple components in the drainage system 100 (e.g., R1 is the aspiration conduit 120 and R2 is the drainage device 110), representing multiple sequential flow resistances as shown in FIGS. 4A-4D . Here, R1 and R2 are different from one another. For example, the first flow resistance portion can be provided by the conduit 120, and the second flow resistance portion can be provided by the wall 112 of the drainage device. In further examples, the first flow resistance portion and the third flow resistance portion may both be provided by the conduit 120 or may both be provided by the wall 112. In these examples, the first flow resistance may be less than the second flow resistance. In other examples, the first flow resistance may be greater than the second flow resistance.

[0103] In examples, the flow path can have an additional flow resistance (e.g., a third, fourth, fifth, etc.). For example, the flow path can have a third flow resistance portion having a third flow resistance. In examples, each of the first flow resistance and the third flow resistance can be greater than the third flow resistance. In examples, each of the first flow resistance, the second flow resistance, and the third flow resistance can be different from one another. In examples, the first flow resistance and the second flow resistance can be defined by the inlet conduit 120, and the third flow resistance can be defined by the drainage device 110. In other examples, the first flow resistance and the second flow resistance can be defined by the drainage device 110, and the third flow resistance can be defined by the inlet conduit 120. In yet other examples, each of the first flow resistance, the second flow resistance, and the third flow resistance can be defined by the inlet conduit 120 or alternatively by the drainage device 110. These examples are just a few of the many examples provided by the present disclosure.

[0104] Note that the numbers shown in the bar graph of Figure 4E are for illustrative purposes only, and one of ordinary skill in the art will recognize that many permutations exist and are well within the scope of the present disclosure.

[0105] FIG. 5A shows a flowchart of a method 500 consistent with embodiments of the present disclosure. As shown, method 500 is useful for forming a glaucoma drainage device disclosed herein and may include drainage systems disclosed elsewhere herein, including drainage system 100. In step 501, method 500 may include disposing a first portion of a first microporous material over a second portion of a second microporous material. Each of the first microporous material and the second microporous material transitions from a hydrophobic state to a hydrophilic state. In step 503, method 500 may include securing the first portion to the second portion to form a wall having a reservoir therebetween. The reservoir may be configured for fluid communication within the eye to receive drainage fluid from the interior of the eye into the reservoir. The wall may define a variable flow resistance as the wall transitions from a hydrophobic state to a hydrophilic state. In an example, in step 505, method 500 may include securing an aspiration conduit between the first portion and the second portion. The intake conduit may be configured to receive the effluent.

[0106] Users can exercise caution when constructing the drainage system, particularly as it relates to bonding portions thereof. In an example, securing the first portion to the second portion can include inhibiting bonding of the first microporous membrane to the fourth microporous membrane. In an example, securing the first portion to the second portion can include arranging the first layer and the second layer in a stacked configuration such that the first microporous membrane and the fourth microporous membrane are the outermost membranes of the wall, and the second microporous membrane and the third microporous membrane are the innermost membranes of the wall.

[0107] Another method 550 is shown in FIG. 5B. This method is a method of using a drainage device disclosed elsewhere herein, including drainage device 110. In step 551, method 550 can include directing drainage fluid from within the human body toward a reservoir within the drainage device. In step 553, method 550 can include directing the drainage fluid to encounter a first flow resistance in the flow path. In step 555, method 550 can include collecting the drainage fluid in the reservoir until the microporous material transitions from a hydrophobic state to a partially hydrophilic state. In step 557, method 550 can include directing the drainage fluid to flow from the reservoir through the compliant wall to a body portion external to the eye.

[0108] While the systems shown in FIGS. 1A-1C are provided as examples of various system features, combinations of these illustrated features are clearly within the scope of the present invention, and the examples and illustrations thereof are not intended to suggest that the inventive concepts provided herein are limited from fewer features, additional features, or alternative features to one or more of those features shown in FIGS. 1A-1C. For example, in various embodiments, components and / or features of the systems shown in FIGS. 1A-1C can include components and features described with reference to other figures, such as FIGS. 2A-2E, 3A-3C, 4A-4E, and 5A-5B. It should also be understood that vice versa is true. One or more of the components shown in FIGS. 1A-1C can be used in addition to or as a substitute for components shown in FIGS. 2A-2E, 3A-3C, 4A-4E, and 5A-5B. This applies to all figures and the components and features shown therein and described with reference thereto.

[0109] 6A and 6B show examples of a method for testing whether a surface is hydrophobic or hydrophilic, also known as the "sessile drop method." Such tests are typically performed using optical tensiometers, ranging from manual instruments to fully automated systems. In both of these examples, a drop of liquid or fluid ("liquid") is placed on the surface to be tested. In this case, it is the wall 112 (represented by the horizontal arrow) of the glaucoma drainage device 110. Subsequently, by taking an image of the drop using a high-resolution camera, the static contact angle (Θ) of the liquid is measured from the surface, i.e., the wall 112, from which the contact angle can be automatically determined using any suitable software. In FIG. 6A, the contact angle is obtuse, i.e., greater than 90 degrees, indicating that the surface of the wall 112 is hydrophobic. In FIG. 6B, the contact angle is acute, i.e., less than 90 degrees, indicating that the surface of the wall 112 is hydrophilic. In some instances, the transition from a hydrophobic state to a hydrophilic state constitutes a decrease in contact angle of at least 10 degrees, at least 15 degrees, at least 20 degrees, at least 25 degrees, at least 30 degrees, at least 35 degrees, at least 40 degrees, at least 45 degrees, at least 50 degrees, at least 55 degrees, at least 60 degrees, at least 65 degrees, at least 70 degrees, at least 75 degrees, at least 80 degrees, at least 85 degrees, at least 90 degrees, or any suitable value or range therebetween. As previously explained, the wall 112, and more particularly the microporous material thereof, can transition from a hydrophobic state to a hydrophilic state, and the speed or rate of this transition can be measured using this method.

[0110] The invention of this application has been described above generally and with reference to specific embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments without departing from the scope of the present disclosure. Therefore, it is intended that the embodiments cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. (Aspect) (Aspect 1) 1. A glaucoma shunt for draining fluid from an eye to tissue surrounding the eye, said glaucoma shunt being implantable at least partially within the tissue of the eye, said glaucoma shunt comprising: a shunt body formed from a microporous material arranged to form a reservoir within the shunt body; and a conduit having a proximal end in fluid communication with the reservoir and a distal end opposite the proximal end; Including, a distal end of the conduit insertable into the eye to facilitate drainage of fluid into the conduit through the distal end of the conduit; A glaucoma shunt, wherein the conduit and the reservoir together define a flow path for draining fluid to flow through the conduit to the reservoir and through the microporous material to tissues surrounding the eye, the flow path exhibiting variable flow resistance along the conduit, the conduit having a plurality of sequential flow resistances defined therein, the plurality of sequential flow resistances having a first flow resistance and a second flow resistance defined therein, the first flow resistance being different from the second flow resistance. (Aspect 2) the shunt body having a continuous wall defining the reservoir and a reservoir opening in the continuous wall communicating with the internal reservoir and in which a conduit is matingly received; and 2. A glaucoma shunt as described in embodiment 1, wherein at least a portion of the continuous wall has a wall portion made of a microporous material, the wall portion having an inner side facing the internal reservoir and an opposite outer side facing the external region of the human eye, the inner side of the wall portion having a low-porosity surface extending throughout the inner side of the wall portion, and the outer side of the wall portion having alternating surfaces including low-porosity surfaces disposed between high-porosity surfaces. (Aspect 3) 2. The glaucoma shunt of embodiment 1, wherein the first flow resistance is less than the second flow resistance. (Aspect 4) 2. The glaucoma shunt of embodiment 1, wherein the first flow resistance is greater than the second flow resistance. (Aspect 5) 2. The glaucoma shunt of embodiment 1, wherein the microporous material defines a third flow resistance in the flow path. (Aspect 6) A glaucoma shunt as described in embodiment 5, wherein the microporous material is configured to transition from a hydrophobic state to a hydrophilic state when exposed to a fluid, and the second flow resistance corresponds to a rate of change of pressure relative to flow rate over time when fluid engages the microporous material defining the reservoir. (Aspect 7) 7. The glaucoma shunt of embodiment 6, wherein the rate of change corresponds to the density of the porosity of the microporous material. (Aspect 8) 8. The glaucoma shunt of embodiment 7, wherein the microporous material has a variable porosity across the thickness of the microporous material. (Aspect 9) 6. The glaucoma shunt of embodiment 5, wherein the first flow resistance corresponds to a ratio of an inner diameter of the conduit to a thickness of the conduit. (Aspect 10) 2. A glaucoma shunt as described in embodiment 1, wherein the first flow resistor and the second flow resistor are oriented in a series configuration so that fluid flowing through the flow path encounters the first flow resistor before encountering the second flow resistor. (Aspect 11) 2. The glaucoma shunt of embodiment 1, wherein the variable flow resistance along the conduit further comprises a third flow resistance. (Aspect 12) 12. The glaucoma shunt of claim 11, wherein each of the first flow resistance and the third flow resistance is greater than the second flow resistance. (Aspect 13) 12. The glaucoma shunt of claim 11, wherein each of the first flow resistance, the second flow resistance, and the third flow resistance is different from each other. (Aspect 14) 1. A drainage device for directing drainage fluid from inside an eye to a body part outside the eye, the drainage device including a flow path configured to facilitate drainage of fluid from inside the eye to surrounding tissue outside the eye, the flow path providing a variable flow resistance to drainage fluid passing through the flow path, the flow path having a first flow resistance portion having a first flow resistance and a second flow resistance portion having a second flow resistance, the first flow resistance being different from the second flow resistance. (Aspect 15) 15. The drainage device of claim 14, wherein the first flow resistance is less than the second flow resistance. (Aspect 16) 15. The drainage device of claim 14, wherein the first flow resistance is greater than the second flow resistance. (Aspect 17) A drainage device as described in aspect 14, wherein the flow path is disposed between a microporous material configured to transition from a hydrophobic state to a hydrophilic state when exposed to the drainage fluid, and the second flow resistance corresponds to a rate of change of pressure relative to flow rate over time when the fluid engages the microporous material. (Aspect 18) 18. The drainage device of claim 17, wherein the rate of change corresponds to the density of the porosity of the microporous material. (Aspect 19) 20. The drainage device of claim 18, wherein the microporous material has a variable porosity across the thickness of the microporous material. (Aspect 20) 15. The drainage device of claim 14, wherein the first flow resistance corresponds to a diameter of the flow path. (Aspect 21) A drainage device as described in embodiment 14, wherein the first flow resistance and the second flow resistance are oriented in a series configuration so that fluid flowing through the flow path encounters the first flow resistance before encountering the second flow resistance. (Aspect 22) 15. The drainage device of embodiment 14, wherein the flow path further comprises a third flow resistance portion having a third flow resistance. (Aspect 23) 23. The drainage device of claim 22, wherein each of the first flow resistance and the third flow resistance is greater than the second flow resistance. (Aspect 24) 23. The drainage device of claim 22, wherein the first flow resistance, the second flow resistance, and the third flow resistance are different from each other. (Aspect 25) 1. A method of forming a drainage device, the method comprising: disposing one or more microporous materials to form a device body having a reservoir defined therein; and securing a conduit to said reservoir such that the conduit is in fluid communication with said reservoir; Including, the reservoir is configured to receive and store a fluid; The conduit and the reservoir define a flow path of a drainage device, the flow path having a variable flow resistance to drainage passing through the flow path, the flow path having a first flow resistance portion having a first flow resistance and a second flow resistance portion having a second flow resistance, the first flow resistance being different from the second flow resistance. (Aspect 26) 26. The method of claim 25, wherein forming the reservoir comprises fixing a first portion of the microporous material to a second portion of the microporous material to form the reservoir therebetween, the method further comprising fixing the conduit between the first and second portions, the conduit being configured to receive drainage. (Aspect 27) 27. The method of embodiment 26, wherein the one or more microporous materials include a first layer having a first microporous membrane bonded to a second microporous membrane and a second layer including a third microporous membrane bonded to a fourth microporous membrane, and bonding the first portion to the second portion includes bonding the second microporous membrane to the third microporous membrane. (Aspect 28) 28. The method of claim 27, wherein the second microporous membrane and the third microporous membrane are bonded to each other along the peripheral edges of the first and second layers to define an expandable reservoir disposed between the second and third microporous membranes, the second and third microporous membranes are configured to resist tissue ingrowth, and the first and fourth microporous membranes are configured to permit tissue ingrowth, and the second and third microporous membranes have an expanded state that is maintained adjacent the peripheral edges of the first and second layers. (Aspect 29) 28. The method of embodiment 27, wherein fixing the first portion to the second portion comprises refraining from bonding the first microporous membrane to the fourth microporous membrane. (Aspect 30) 28. The method of embodiment 27, wherein fixing the first portion to the second portion comprises arranging the first layer and the second layer in a stack configuration such that the first microporous membrane and the fourth microporous membrane are the outermost membranes of the device body, and the second microporous membrane and the third microporous membrane are the innermost membranes of the device body. (Aspect 31) 1. A glaucoma drainage device for draining fluid from an interior region of a human eye to an exterior region of the human eye, said glaucoma drainage device comprising: a body having a continuous wall defining an internal reservoir within the body and a reservoir opening in the continuous wall in communication with the internal reservoir; a conduit extending from said body by a conduit length; Including, the conduit has opposing first and second conduit ends defining a passageway therethrough extending between the opposing first and second ends, the first conduit end engaging an internal reservoir opening to provide a fluid connection between the second conduit end and the internal reservoir, and the conduit length being sufficient to position the first conduit end in an external region of the human eye and the second conduit end in an internal region of the human eye; A glaucoma drainage device, wherein at least a portion of the continuous wall has a wall portion made of a microporous material, the wall portion having an inner side facing the internal reservoir and an opposite outer side facing an external region of the human eye, the inner side of the wall portion having a low-porosity surface extending throughout the inner side of the wall portion, and the outer side of the wall portion having alternating surfaces including low-porosity surfaces disposed between high-porosity surfaces. (Aspect 32) A glaucoma drainage device as described in aspect 31, wherein the wall portion defines a wall portion thickness extending between the inner and outer sides, and the wall portion thickness defines an interior region of the wall portion having a transitional porosity between the porosity of the inner low-porosity surface and the porosity of the outer high-porosity surface. (Aspect 33) A glaucoma drainage device as described in aspect 31, wherein the wall portion defines a wall portion thickness extending between the inner and outer sides, and the wall portion thickness defines an interior region of the wall portion extending between the inner low-porosity surface and the outer low-porosity surface, and the interior region has an interior region porosity equal to the porosity of the inner and outer low-porosity surfaces. (Aspect 34) 32. The glaucoma drainage device of claim 31 , wherein the wall portion defines a wall portion thickness extending between the inner and outer sides, the wall portion thickness defining an interior region of the wall portion extending between the inner low-porosity surface and the outer high-porosity surface, the interior region having an interior region porosity equal to the porosity of the inner low-porosity surface. (Aspect 35) 32. The glaucoma drainage device of claim 31 , wherein the wall portion defines a wall portion thickness extending between the inner and outer sides, the wall portion thickness defining an interior region of the wall portion extending between the inner low-porosity surface and the outer high-porosity surface, the interior region having an interior region porosity equal to the porosity of the outer high-porosity surface. (Aspect 36) A glaucoma drainage device as described in aspect 31, wherein the fluid connection between the second conduit end and the internal reservoir further extends from the internal reservoir through the microporous material, providing fluid communication from the internal reservoir to an external region of the human eye. (Aspect 37) 37. The glaucoma drainage device of embodiment 36, wherein the fluid communication defines a flow path through the microporous material. (Aspect 38) 38. The glaucoma drainage device of claim 37, wherein the flow path through the microporous material is in a direction away from the internal reservoir. (Aspect 39) 38. The glaucoma drainage device of embodiment 37, wherein the flow path through the microporous material proceeds from a low porosity microporous region to a high porosity microporous region.

Claims

1. 1. A glaucoma shunt for draining fluid from an eye to tissue surrounding the eye, said glaucoma shunt being implantable at least partially within the tissue of the eye, said glaucoma shunt comprising: a shunt body formed from a microporous material arranged to form a reservoir within the shunt body; and a conduit having a proximal end in fluid communication with the reservoir and a distal end opposite the proximal end; Including, a distal end of the conduit insertable into the eye to facilitate drainage of fluid into the conduit through the distal end of the conduit; 1. A glaucoma shunt, wherein the conduit and the reservoir together define a flow path for draining fluid to flow through the conduit to the reservoir and through the microporous material to tissue surrounding the eye, the flow path exhibiting a variable flow resistance along the conduit, the conduit having a plurality of sequential flow resistances defined therein, the plurality of sequential flow resistances having a first flow resistance and a second flow resistance defined therein, the first flow resistance being different from the second flow resistance; the shunt body having a continuous wall defining the reservoir and a reservoir opening in the continuous wall communicating with the internal reservoir and in which a conduit is matingly received; and A glaucoma shunt, wherein at least a portion of the continuous wall has a wall portion made of a microporous material, the wall portion having an inner side facing the internal reservoir and an opposite outer side facing the external region of the human eye, the inner side of the wall portion having a low-porosity surface extending throughout the inner side of the wall portion, and the outer side of the wall portion having alternating surfaces including low-porosity surfaces disposed between high-porosity surfaces.

2. The glaucoma shunt of claim 1 , wherein the first flow resistance is less than the second flow resistance.

3. The glaucoma shunt of claim 1 , wherein the first flow resistance is greater than the second flow resistance.

4. The glaucoma shunt of claim 1 , wherein the microporous material defines a third flow resistance of the flow path.

5. 5. The glaucoma shunt of claim 4, wherein the microporous material is configured to transition from a hydrophobic state to a hydrophilic state when exposed to a fluid, and the second flow resistance corresponds to a rate of change of pressure relative to flow rate over time when fluid engages the microporous material defining the reservoir.

6. The glaucoma shunt of claim 5 , wherein the rate of change corresponds to a density in porosity of the microporous material.

7. The glaucoma shunt of claim 6 , wherein the microporous material has a variable porosity across the thickness of the microporous material.

8. The glaucoma shunt of claim 4 , wherein the first flow resistance corresponds to a ratio of an inner diameter of the conduit to a thickness of the conduit.

9. 2. The glaucoma shunt of claim 1, wherein the first flow resistance and the second flow resistance are oriented in a series configuration such that fluid flowing through the flow path encounters the first flow resistance before encountering the second flow resistance.

10. The glaucoma shunt of claim 1 , wherein the variable flow resistance along the conduit further comprises a third flow resistance.

11. The glaucoma shunt of claim 10 , wherein each of the first flow resistance and the third flow resistance is greater than the second flow resistance.

12. 11. The glaucoma shunt of claim 10, wherein the first flow resistance, the second flow resistance, and the third flow resistance are each different from one another.

13. 1. A method of forming a drainage device, the method comprising: disposing one or more microporous materials to form a device body having a reservoir defined therein; and securing a conduit to said reservoir such that the conduit is in fluid communication with said reservoir; Including, the reservoir is configured to receive and store a fluid; 1. A method of drainage device, comprising: the conduit and the reservoir defining a flow path of the drainage device, the flow path having a variable flow resistance to drainage fluid passing through the flow path, the flow path having a first flow resistance portion having a first flow resistance and a second flow resistance portion having a second flow resistance, the first flow resistance being different from the second flow resistance; the device body having a continuous wall defining the reservoir and a reservoir opening in the continuous wall in communication with the internal reservoir and into which a conduit is matingly received; and At least a portion of the continuous wall has a wall portion made of a microporous material, the wall portion having an inner side facing the internal reservoir and an opposite outer side facing an external region of the human eye, the inner side of the wall portion having a low-porosity surface extending throughout the inner side of the wall portion, and the outer side of the wall portion having alternating surfaces including low-porosity surfaces disposed between high-porosity surfaces.

14. 14. The method of claim 13, wherein forming the reservoir comprises securing a first portion of the microporous material to a second portion of the microporous material to form the reservoir therebetween, the method further comprising securing the conduit between the first and second portions, the conduit configured to receive drainage.

15. 15. The method of claim 14, wherein the one or more microporous materials include a first layer having a first microporous membrane bonded to a second microporous membrane and a second layer including a third microporous membrane bonded to a fourth microporous membrane, and bonding the first portion to the second portion includes bonding the second microporous membrane to the third microporous membrane.

16. 16. The method of claim 15, wherein the second and third microporous membranes are bonded to one another along the peripheries of the first and second layers to define an expandable reservoir disposed between the second and third microporous membranes, the second and third microporous membranes are configured to resist tissue ingrowth, and the first and fourth microporous membranes are configured to permit tissue ingrowth, and the second and third microporous membranes have an expanded state that is maintained adjacent the peripheries of the first and second layers.

17. 16. The method of claim 15, wherein securing the first portion to the second portion comprises refraining from bonding the first microporous membrane to the fourth microporous membrane.

18. 16. The method of claim 15, wherein fixing the first portion to the second portion comprises arranging the first layer and the second layer in a stack configuration such that the first microporous membrane and the fourth microporous membrane are the outermost membranes of the device body and the second microporous membrane and the third microporous membrane are the innermost membranes of the device body.

19. 1. A glaucoma drainage device for draining fluid from an interior region of a human eye to an exterior region of the human eye, said glaucoma drainage device comprising: a body having a continuous wall defining an internal reservoir within the body and a reservoir opening in the continuous wall in communication with the internal reservoir; a conduit extending from said body by a conduit length; Including, the conduit has opposing first and second conduit ends defining a passageway therethrough extending between the opposing first and second ends, the first conduit end engaging an internal reservoir opening to provide a fluid connection between the second conduit end and the internal reservoir, and the conduit length being sufficient to position the first conduit end in an external region of the human eye and the second conduit end in an internal region of the human eye; A glaucoma drainage device, wherein at least a portion of the continuous wall has a wall portion made of a microporous material, the wall portion having an inner side facing the internal reservoir and an opposite outer side facing an external region of the human eye, the inner side of the wall portion having a low-porosity surface extending throughout the inner side of the wall portion, and the outer side of the wall portion having alternating surfaces including low-porosity surfaces disposed between high-porosity surfaces.

20. 20. The glaucoma drainage device of claim 19, wherein the wall portion defines a wall portion thickness extending between the inner and outer sides, the wall portion thickness defining an interior region of the wall portion having a transitional porosity between the porosity of the inner, low-porosity surface and the porosity of the outer, high-porosity surface.

21. 20. The glaucoma drainage device of claim 19, wherein the wall portion defines a wall portion thickness extending between the inner and outer sides, the wall portion thickness defining an interior region of the wall portion extending between the inner low-porosity surface and the outer low-porosity surface, the interior region having an interior region porosity equal to the porosity of the inner and outer low-porosity surfaces.

22. 20. The glaucoma drainage device of claim 19, wherein the wall portion defines a wall portion thickness extending between the inner and outer sides, the wall portion thickness defining an interior region of the wall portion extending between the inner low-porosity surface and the outer high-porosity surface, the interior region having an interior region porosity equal to the porosity of the inner low-porosity surface.

23. 20. The glaucoma drainage device of claim 19, wherein the wall portion defines a wall portion thickness extending between the inner and outer sides, the wall portion thickness defining an interior region of the wall portion extending between the inner low-porosity surface and the outer high-porosity surface, the interior region having an interior region porosity equal to the porosity of the outer high-porosity surface.

24. 20. The glaucoma drainage device of claim 19, wherein the fluid connection between the second conduit end and the internal reservoir further extends from the internal reservoir through the microporous material to provide fluid communication from the internal reservoir to an external region of the human eye.

25. 25. The glaucoma drainage device of claim 24, wherein the fluid communication defines a flow path through the microporous material.

26. 26. The glaucoma drainage device of claim 25, wherein the flow path through the microporous material is in a direction away from the internal reservoir.

27. 26. The glaucoma drainage device of claim 25, wherein the flow path through the microporous material proceeds from a low porosity microporous region to a high porosity microporous region.

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