Integrated aqueous shunt for the treatment of glaucoma

Abstract

To provide a glaucoma treatment device.SOLUTION: A glaucoma treatment device includes a plurality of microporous layers arranged together so as to form a microporous body configured to facilitate an evacuation of fluid from a fluid-filled body cavity and reabsorption of drained aqueous humor by the body through tissue surrounding the glaucoma treatment device. In some examples, the glaucoma treatment device includes one or more portions configured to resist cellular internal growth and one or more portions configured to allow the cellular internal growth. Especially, the outside thereof may comprise or be defined by one or more membranes, where the membranes are porous or otherwise permeable to the fluid of the fluid-filled body cavity.SELECTED DRAWING: Figure 1

Description

[Background technology]

[0001] background Aqueous humor is the fluid that fills the anterior chamber of the eye and contributes to intraocular pressure, or fluid pressure within the eye. Glaucoma is a progressive eye disease characterized by elevated intraocular pressure. This increase in intraocular pressure is usually caused by an insufficient amount of aqueous humor being reabsorbed by the body. In some cases, aqueous humor is not absorbed quickly enough or at all, and in other cases, aqueous humor is additionally or alternatively produced too quickly. Increased intraocular pressure is associated with gradual and sometimes permanent vision loss in the affected eye.

[0002] Many attempts have been made to treat glaucoma. However, some conventional devices lack the flexibility, conformability, and device / tissue adhesion necessary to avoid relative movement between the device and surrounding tissue. Such movement can lead to persistent irritation of the surrounding tissue. Irritation, in turn, can lead to increased chronic inflammatory tissue response, excessive scarring at the device site, and increased risk of device erosion through the conjunctiva and endophthalmitis. In the absence of erosion, scar tissue effectively inhibits aqueous humor reabsorption. These complications can act to inhibit proper device function. The resulting effect is a gradual increase in intraocular pressure and progression of glaucoma. Summary of the Invention

[0003] According to one example ("Example 1"), a biological fluid drainage device includes a body including a first microporous membrane, a second microporous membrane, a third microporous membrane, and a fourth microporous membrane in a stacked configuration, the second and third microporous membranes being disposed between the first and fourth microporous membranes, and an expandable reservoir being defined between the second and third microporous membranes, wherein the second and third microporous membranes are configured to resist tissue ingrowth and the first and fourth microporous membranes are configured to allow tissue ingrowth, and a fluid conduit having a first end and a second end, the first end being fluidly coupled to the reservoir and the second end extending outside the body, and being insertable into a fluid-filled body cavity such that fluid from the fluid-filled body cavity can be transferred to the reservoir.

[0004] In addition to Example 1, according to another example ("Example 2"), the second and third microporous membranes are partially bonded to each other such that portions of the second and third microporous membranes are free to slide relative to each other or separate from each other.

[0005] According to another example ("Example 3") in addition to either of Examples 1 and 2, the second and third microporous membranes each have a permeability that is different from the permeability of each of the first and fourth microporous membranes.

[0006] According to another example ("Example 4") in addition to any of Examples 1-3, at least one of the first, second, third, and fourth microporous membranes comprises expanded polytetrafluoroethylene.

[0007] In addition to any of the above examples, according to another example ("Example 5"), the fluid is aqueous humor and the fluid-filled body cavity is the anterior chamber.

[0008] In addition to any of the above examples, according to another example ("Example 6"), the device further includes a fifth microporous membrane disposed adjacent to the body, the fifth microporous membrane extending between the body and the second end of the fluid conduit.

[0009] In addition to Example 6, according to another example ("Example 7"), the fifth microporous membrane is configured to allow tissue ingrowth.

[0010] According to another example ("Example 8") in addition to any of Examples 6-7, the fifth microporous membrane is bonded to the fluid conduit.

[0011] In addition to any of Examples 6-8, according to another example ("Example 9"), the fifth microporous membrane is integral with one of the first, second, third, or fourth microporous membranes.

[0012] In addition to Example 9, according to another example ("Example 10"), the fifth microporous membrane and the first microporous membrane are the same microporous membrane.

[0013] According to another example ("Example 11") in addition to any of Examples 6-10, the device further includes a sixth microporous membrane disposed adjacent to the body, the sixth microporous membrane extending between the body and the second end of the fluid conduit.

[0014] In addition to Example 11, according to another example ("Example 12"), the sixth microporous membrane and the fourth microporous membrane are the same microporous membrane.

[0015] According to another example ("Example 13") in addition to any of Examples 11-12, the sixth microporous membrane includes perforations sized to accommodate a fluid conduit such that, upon implantation, the fluid conduit can be extended through the perforations into a fluid-filled body cavity.

[0016] In addition to any of the above examples, according to another example ("Example 14"), the first and fourth microporous membranes are configured to remain permeable to the fluid after tissue ingrowth occurs in the first and fourth microporous membranes, respectively.

[0017] In addition to any of the above examples, according to another example ("Example 15"), the reservoir is configured to expand when the fluid is transferred to the reservoir.

[0018] In addition to Example 15, according to another example ("Example 16"), the body is configured to adopt a predetermined profile as a result of expansion of the reservoir.

[0019] In addition to any of the above examples, according to another example ("Example 17"), the first, second, third, and fourth microporous membranes each comprise a plurality of pores, wherein the plurality of pores in the second and third microporous membranes are sized to resist tissue ingrowth, and the plurality of pores in the first and fourth microporous membranes are sized to permit tissue ingrowth.

[0020] In addition to any of the above examples, according to another example ("Example 18"), one of the second and third microporous membranes is hydrophobic and one of the first and fourth microporous membranes is hydrophilic. In addition to any of the above examples, according to another example, the first, second, third, and fourth microporous membranes are hydrophobic. In addition to any of the above examples, according to another example, the first, second, third, and fourth microporous membranes are hydrophilic.

[0021] In addition to any of the above examples, according to another example ("Example 19"), one of the first, second, third, and fourth microporous membranes is formed from multiple microporous layers of expanded polytetrafluoroethylene.

[0022] According to another example ("Example 20"), an aqueous humor diffusion device includes a first proliferative diffusion membrane configured to permit tissue ingrowth, a first constrictive diffusion membrane configured to resist tissue ingrowth, the first constrictive diffusion membrane bonded to the first proliferative diffusion membrane, a second constrictive diffusion membrane configured to resist tissue ingrowth, the second constrictive diffusion membrane bonded to the first constrictive diffusion membrane such that a first region of the second constrictive diffusion membrane is bonded to the first constrictive diffusion membrane and a second portion of the second constrictive diffusion membrane is unbonded from the first constrictive diffusion membrane, the unbonded second region defining an expandable reservoir, and a second proliferative diffusion membrane configured to permit tissue ingrowth, the second constrictive diffusion membrane bonded to the second constrictive diffusion membrane.

[0023] In addition to Example 20, according to another example (Example 21), the first and second proliferative diffusion membranes include a plurality of pores configured to permit tissue ingrowth, and the first and second constrictive diffusion membranes include a plurality of pores configured to resist tissue ingrowth.

[0024] In addition to any of Examples 20 to 22, according to another example ("Example 22"), the first region of the second constricting diffusion membrane is the peripheral region of the second constricting diffusion membrane, the first region of the second constricting diffusion membrane is bonded to the peripheral region of the first constricting diffusion membrane, and the second region of the second constricting diffusion membrane is the region inside the peripheral region of the second constricting diffusion membrane.

[0025] According to another example ("Example 23") in addition to any of Examples 20-22, the device further includes a fluid conduit having a first end and a second end, the first end being in fluid communication with the reservoir and the second end extending away from the first and second constrictive diffusion membranes, and insertable into a fluid-filled body cavity such that fluid from the fluid-filled body cavity can transfer to the reservoir.

[0026] In addition to Example 23, according to another example ("Example 24"), the device further includes a third proliferative diffusion membrane including a plurality of pores sized to allow tissue ingrowth, the third proliferative diffusion membrane positioned adjacent to the first proliferative diffusion membrane and extending along the fluid conduit between the first proliferative diffusion membrane and the second end of the fluid conduit.

[0027] In addition to Example 24, according to another example ("Example 25"), the third proliferative membrane and the first proliferative diffusion membrane are the same proliferative diffusion membrane.

[0028] According to another example ("Example 26") in addition to any of Examples 24-25, the third proliferative diffusion membrane is bonded to the fluid conduit.

[0029] According to another example ("Example 27") in addition to any of Examples 23-26, the device further includes a fourth proliferative diffusion membrane including a plurality of pores sized to allow tissue ingrowth, the fourth proliferative diffusion membrane positioned adjacent to the second proliferative diffusion membrane and extending along the fluid conduit between the second proliferative diffusion membrane and the second end of the fluid conduit.

[0030] In addition to Example 27, according to another example ("Example 28"), the fourth proliferative membrane and the second proliferative diffusion membrane are the same proliferative membrane.

[0031] According to another example ("Example 29") in addition to any of Examples 27-28, the fourth proliferative diffusion membrane includes perforations sized to accommodate fluid conduits such that, upon implantation, the fluid conduits extend through the perforations into a fluid-filled body cavity.

[0032] In addition to any of Examples 20-29, according to another example ("Example 30"), the fluid-filled body cavity is the anterior chamber of a patient's eye, and the fluid is aqueous humor.

[0033] According to another example ("Example 31"), a method of forming a glaucoma drainage device includes providing a first proliferative diffusion membrane and a second proliferative diffusion membrane, each configured to permit tissue ingrowth; providing a first constrictive diffusion membrane and a second constrictive diffusion membrane, each configured to resist tissue ingrowth; bonding the first proliferative diffusion membrane to the first constrictive diffusion membrane; bonding the first constrictive diffusion membrane to the second constrictive diffusion membrane such that a first region of a first interface surface of the second constrictive diffusion membrane is bonded to the first constrictive diffusion membrane and a second region of the first interface surface is not bonded to the first constrictive diffusion membrane, wherein the unbonded second region defines an expandable reservoir; and forming an aqueous humor diffusion member by bonding the second proliferative diffusion membrane to the second constrictive diffusion membrane. The method further includes coupling a fluid conduit to the aqueous humor diffusing member such that the fluid conduit is fluidly coupled with the reservoir such that the conduit is operable to deliver the drained aqueous humor to the reservoir.

[0034] In addition to Example 31, according to another example (Example 32), the aqueous humor diffusion member further includes a third proliferative diffusion membrane configured to allow tissue ingrowth, the third proliferative membrane being positioned adjacent to the first proliferative diffusion membrane and extending along the fluid conduit.

[0035] In addition to Example 32, according to another example ("Example 33"), the aqueous humor diffusion member further includes a fourth proliferative diffusion membrane configured to allow tissue ingrowth, the fourth proliferative membrane being positioned adjacent to the second proliferative diffusion membrane and extending along the fluid conduit.

[0036] In addition to any of Examples 31-33, according to another example ("Example 34"), the method further includes perforating one of the first, second, third, or fourth proliferative diffusion membranes to include a plurality of pores sized to permit tissue ingrowth.

[0037] In addition to any of Examples 32 to 34, according to another example ("Example 35"), the third proliferative diffusion membrane and the first proliferative diffusion membrane are the same proliferative diffusion membrane.

[0038] In addition to any of Examples 33 to 35, according to another example ("Example 36"), the fourth proliferative diffusion membrane and the second proliferative diffusion membrane are the same proliferative diffusion membrane.

[0039] According to another example ("Example 37") in addition to any of Examples 33-36, the fourth proliferative diffusion membrane includes perforations sized to accommodate fluid conduits such that, upon implantation, the fluid conduits can extend through the perforations into the anterior chamber.

[0040] According to another example ("Example 38"), a biological fluid drainage device includes a body including a first microporous membrane, a second microporous membrane, and a third microporous membrane, the first microporous membrane being disposed between the second and third microporous membranes, the first microporous membrane including a plurality of pores sized to resist tissue ingrowth, and the second and third microporous membranes each including a plurality of pores sized to allow tissue ingrowth, an expandable reservoir being defined between the first and third microporous membranes, and the fluid conduit having a first end and a second end, the first end being fluidly coupled to the reservoir and the second end extending outside the body, and being insertable into a fluid-filled body cavity such that fluid from the fluid-filled body cavity can transfer to the reservoir.

[0041] In addition to any of the above examples, according to another example ("Example 39"), one or more of the first and fourth microporous membranes are hydrophobic, and the second and third microporous membranes are hydrophilic. [Brief explanation of the drawings]

[0042] BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are included to provide a further understanding of embodiments of the present disclosure, and are incorporated into and constitute a part of this specification, illustrating examples and, together with the description, serving to explain the principles of the present disclosure.

[0043] [Figure 1] FIG. 1 is a diagram of a glaucoma drainage system consistent with various aspects of the present disclosure.

[0044] [Figure 2A] FIG. 2A is a diagram of a glaucoma drainage system in a contracted state consistent with various aspects of the present disclosure.

[0045] [Figure 2B] FIG. 2B is a diagram of a glaucoma drainage system in an inflated state consistent with various aspects of the present disclosure.

[0046] [Figure 3] FIG. 3 is an exploded view of the glaucoma drainage system shown in FIG.

[0047] [Figure 4] 4A-4D are diagrams of constrictive diffusion membrane interfacial surfaces consistent with various embodiments of the present disclosure.

[0048] [Figure 5] FIG. 5 is a diagram of a glaucoma drainage system consistent with various aspects of the present disclosure.

[0049] [Figure 6] FIG. 6 is a diagram of a glaucoma drainage system consistent with various aspects of the present disclosure.

[0050] [Figure 7A] FIG. 7A is a diagram of a glaucoma drainage system in a contracted state consistent with various aspects of the present disclosure.

[0051] [Figure 7B] FIG. 7B is a diagram of a glaucoma drainage system in an inflated state consistent with various embodiments of the present disclosure.

[0052] [Figure 8] FIG. 8 is a diagram of a fluid conduit consistent with various embodiments of the present disclosure.

[0053] [Figure 9A] FIG. 9A is a diagram of a glaucoma drainage system consistent with various aspects of the present disclosure.

[0054] [Figure 9B] FIG. 9B is a cross-sectional view of the glaucoma drainage system of FIG. 9A taken along line 9B-9B.

[0055] [Figure 9C] FIG. 9C is a cross-sectional view of the glaucoma drainage system of FIG. 9A taken along line 9C-9C.

[0056] [Figure 10] FIG. 11 is an exploded view of a glaucoma drainage system consistent with various aspects of the present disclosure.

[0057] [Figure 11] FIG. 11 is a diagram of a glaucoma drainage system implanted within ocular tissue consistent with various aspects of the present disclosure.

[0058] [Figure 12] FIG. 12 is a diagram of a glaucoma drainage system implanted within ocular tissue consistent with various aspects of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0059] Detailed Description Those skilled in the art will readily appreciate that the various embodiments of the inventive concepts provided in this disclosure can be implemented by any number of methods and devices configured to perform their 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. As used herein, the term "diffusion membrane" is intended to encompass one or more proliferative diffusion membranes and / or one or more constrictive diffusion membranes.

[0060] Various aspects of the present disclosure are directed to glaucoma drainage devices, systems, and methods. More particularly, the present disclosure relates to devices, systems, and methods for draining aqueous humor from the anterior chamber of a patient's eye so that it can be reabsorbed by the body. Providing a mechanism for reabsorption of drained aqueous humor from the anterior chamber of the eye operates to reduce or otherwise stabilize intraocular pressure.

[0061] A glaucoma drainage system 1000 according to some embodiments is shown in FIG. 1. The glaucoma drainage system 1000 is an implantable medical system that operates to facilitate drainage of fluids, such as aqueous humor, from a fluid-filled body cavity, such as the anterior chamber of the eye. The glaucoma drainage system 1000 includes a fluid conduit 1500 and a body, such as an aqueous humor diffusing member 1002. While the following disclosure refers to the glaucoma drainage system 1000 for use in draining aqueous humor from the anterior chamber of the eye, it should be understood and appreciated by those skilled in the art that the depicted glaucoma drainage system 1000 can be configured and utilized to drain other fluids from other fluid-filled body cavities. In some instances, as described in more detail below, the glaucoma drainage system 1000 further serves to facilitate reabsorption of the drained fluid by the body. For example, in some embodiments, the glaucoma drainage system 1000 provides an interface between the drained aqueous humor and tissues, ducts, and / or cells that have the ability to absorb the aqueous humor and are in sufficient proximity to the glaucoma drainage system 1000 to interact with the drained aqueous humor. Thus, in some instances, aqueous humor drained from the anterior chamber of the eye passes through the glaucoma drainage system 1000 before being reabsorbed by the body.

[0062] In some embodiments, when the glaucoma drainage system 1000 is implanted, aqueous humor drains from the anterior chamber through the fluid conduit 1500. The drained aqueous humor then enters a reservoir in the aqueous humor diffusing member 1002 and permeates through one or more porous membranes in the aqueous humor diffusing member 1002, where it can then be reabsorbed by the body. In various embodiments, in addition to aqueous humor permeability, tissue ingrowth is permitted or promoted along one or more regions of the glaucoma drainage system 1000. For example, the exterior of the aqueous humor diffusing member 1002 can include or be defined by one or more membranes that are porous or otherwise permeable to the fluid of the fluid-filled body cavity (hereinafter referred to as diffusion membranes) and are configured to permit or promote tissue ingrowth. Allowing tissue ingrowth along or within the surface of the glaucoma drainage system 1000 helps promote biointegration of the glaucoma drainage system 1000 into surrounding tissue (e.g., ocular tissue) and facilitates reabsorption of the drained aqueous humor by the surrounding tissue. Additionally, biointegration, including tissue ingrowth and attachment, helps minimize relative movement between the glaucoma drainage system 1000 and the tissue surrounding the glaucoma drainage system 1000, helping to avoid foreign body tissue response, scarring, and / or ocular tissue irritation that could result in erosion of the glaucoma drainage system 1000 and site infection.

[0063] In various embodiments, the aqueous humor diffusing member 1002 includes an interior region defining a reservoir of aqueous humor that drains from the anterior chamber through the fluid conduit 1500. The interior region of the aqueous humor diffusing member 1002 can include one or more membranes (hereinafter referred to as diffusion membranes) that are porous or otherwise permeable to fluid in the fluid-filled body cavity. For example, as discussed in more detail below, the one or more diffusion membranes can be made from a porous medium, such as a polymeric material, that has a microstructure suitable for transporting fluid through the pore spaces of the porous medium. Thus, in some embodiments, the reservoir can be defined by the pore space of one or more diffusion membranes that form the aqueous humor diffusing member 1002. In some embodiments, the aqueous humor diffusing member 1002 can be configured such that the reservoir is additionally or alternatively formed between two or more diffusion membranes that form the aqueous humor diffusing member 1002. For example, in some embodiments, at least a portion of the surface area between adjacently disposed diffusing membranes forming the aqueous humor diffusing member 1002 remains unbonded or unadhered such that the adjacently disposed diffusing membranes are operable to separate from one another along at least a portion of their surface area to form and define reservoirs. In some embodiments, as discussed further below, the reservoirs defined between the adjacently disposed diffusing membranes are operable to expand or dilate in a controlled manner (to a predetermined profile upon expansion) such that the glaucoma drainage system 1000 does not interfere with normal ocular function (e.g., normal eye movements including rotation and blinking).

[0064] In various embodiments, the aqueous humor diffusing member 1002 is sized and shaped to be implantable within a patient's anatomy. For example, in some embodiments, the aqueous humor diffusing member 1002 is sized and shaped to be implantable within an incision in the subconjunctival space (e.g., between the sclera and conjunctiva of a patient's eye). In some embodiments, the aqueous humor diffusing member 1002 is a thin, puck-shaped member. In some embodiments, the aqueous humor diffusing member 1002 has a thickness (e.g., the distance measured between the first outer surface 1004 and the second outer surface 1006) of 0.5 mm or less, e.g., between 0.1 mm and 0.5 mm. However, given different anatomical structures of the human body, the aqueous humor diffusion member 1002 may be thicker than 0.5 mm, provided that the thickness does not interfere with normal eye functions (e.g., turning and blinking) or substantially reduce the flexibility of the aqueous humor diffusion member 1002 to the extent that undesirable relative movement occurs between the glaucoma drainage system 1000 and surrounding tissue upon implantation, resulting in tissue irritation, foreign body tissue response, and / or excessive scar formation.

[0065] In some embodiments, the aqueous humor diffusion member 1002 can have a diameter ranging from 5 mm to 15 mm, e.g., 10 mm. In some embodiments, the aqueous humor diffusion member 1002 can be oval-shaped and can include a major dimension (e.g., along the major axis of the ellipse) of about 30 mm or less and a corresponding minor dimension (e.g., along the major axis of the ellipse) of about 10 mm or less. As discussed above, given different anatomical structures in the human body, the aqueous humor diffusion member 1002 can exceed such dimensions (e.g., 15 mm, 10 mm, and 30 mm), provided that such sizes do not substantially interfere with normal ocular function (e.g., turning and blinking) or substantially reduce the flexibility of the aqueous humor diffusion member to such an extent that undesirable relative movement occurs between the glaucoma drainage system 1000 and surrounding tissue upon implantation, resulting in tissue irritation, foreign body tissue response, and / or excessive scarring. Similarly, the aqueous humor diffusion member 1002 can have a diameter of less than 5 mm, less than 3 mm, or even less than 3 mm, provided that the aqueous humor diffusion member 1002 is operable to contain a sufficient amount of the drained aqueous humor and to promote reabsorption of the aqueous humor to constitute effective treatment for the patient.

[0066] In various embodiments, the fluid conduit 1500, when implanted within the body, operates to fluidly couple the reservoir to a fluid-filled body cavity (e.g., the anterior chamber of the eye), thereby providing a pressure differential between the reservoir and an environment (e.g., atmosphere) external to the glaucoma drainage system 1000. It should be understood, therefore, that upon implantation, the pressure within the reservoir is based, at least in part, on the pressure within the fluid-filled body cavity (e.g., the intraocular pressure in the anterior chamber of the eye). In some embodiments, such a pressure differential causes the reservoir to expand or dilate. Furthermore, in some embodiments, such a pressure differential causes aqueous humor to permeate through the diffusion membrane of the aqueous humor diffusion element 1002. That is, in some embodiments, drained aqueous humor enters the reservoir and permeates through the diffusion membrane of the aqueous humor diffusion element 1002, where it can then be reabsorbed by the body.

[0067] 2A and 2B, a glaucoma drainage system 1000 is shown that includes an aqueous humor diffusing member 1002 that includes a plurality of diffusing membranes. The aqueous humor diffusing member 1002 includes a first outer surface 1004, a second outer surface 1006 opposite the first outer surface 1004, and a periphery 1008. FIG. 2A shows the glaucoma drainage system 1000 in a contracted state. FIG. 2B shows the glaucoma drainage system 1000 in an inflated state, with aqueous humor present in an inflatable or expandable reservoir 1010. Although the glaucoma drainage system 1000 is shown in FIG. 2B in an expanded state in which the glaucoma drainage system 1000 is not uniformly expanded (e.g., the first proliferative and constrictive diffusion membranes 1100 and 1200 are shown to have a generally non-linear configuration, while the second proliferative and constrictive diffusion membranes 1300 and 1400 are shown to have a generally linear configuration), it should be understood that the glaucoma drainage system 1000 may deform uniformly (e.g., the second proliferative and constrictive diffusion membranes 1300 and 1400 may deform in a manner that mirrors the deformation of the first proliferative and constrictive diffusion membranes 1100 and 1200). The aqueous humor diffusion member 1002 includes a body defined by a plurality of diffusion membranes, including first and second proliferative diffusion membranes 1100 and 1400 and first and second constrictive diffusion membranes 1200 and 1300. In some embodiments, the first and second proliferative diffusion membranes 1100 and 1400 and the first and second constrictive diffusion membranes 1200 and 1300 are stacked together as shown to form the aqueous humor diffusion member 1002. As described further below, the first and second proliferative diffusion membranes 1100 and 1400 are configured to permit tissue ingrowth and attachment, while the first and second constrictive diffusion membranes 1200 and 1300 are configured to minimize, resist, or prevent tissue ingrowth and attachment.

[0068] In some embodiments, the first and second proliferative diffusion membranes 1100 and 1400 form or otherwise define the exterior of the aqueous humor diffusion member 1002, while the first and second constrictive diffusion membranes 1200 and 1300 are located between the first and second proliferative diffusion membranes 1100 and 1400 and define the interior region of the aqueous humor diffusion member 1002. In various embodiments, the first and second proliferative diffusion membranes 1100 and 1400 and the first and second constrictive diffusion membranes 1200 and 1300 are each permeable to aqueous humor, respectively, in that they are configured to allow drained aqueous humor (e.g., aqueous humor disposed in a sealed reservoir) to permeate therethrough and / or diffuse across it. However, the first and second proliferative diffusion membranes 1100 and 1400 are configured to allow tissue ingrowth and attachment, while the first and second constrictive diffusion membranes 1200 and 1300 are configured to minimize, resist, or prevent tissue ingrowth and attachment. The configuration of the constrictive diffusion membrane sandwiched or otherwise disposed between the proliferative diffusion membranes as shown in Figures 2A and 2B serves to minimize, for example, the penetration and / or migration of bacteria into the anterior chamber of the eye that exceed the size of the perforations or small holes present in the constrictive diffusion membrane.

[0069] In various examples, the first and second proliferative diffusion membranes 1100 and 1400 of the aqueous humor diffusion member 1002 are microporous, permeable to aqueous humor, and configured to permit ingrowth and / or attachment of ducts and tissue structures. In various embodiments, the first and second constrictive diffusion membranes 1200 and 1300 are also microporous and permeable to aqueous humor, but configured to resist or otherwise minimize ingrowth and attachment of ducts and tissue structures. Thus, in various embodiments, the aqueous humor diffusion member 1002 is fabricated from multiple separate diffusion membranes, including at least the first proliferative diffusion membrane 1100 and at least the first constrictive diffusion membrane 1200.

[0070] 2A and 2B includes separate and distinct first and second proliferative diffusion membranes 1100 and 1400, it should be understood that the aqueous humor diffusion member 1002 can include the first proliferative diffusion membrane 1100 without the need for the separate and distinct second proliferative diffusion membrane 1400. For example, the first proliferative diffusion membrane 1100 can be folded such that the first proliferative diffusion membrane 1100 surrounds the constrictive diffusion membrane portion of the aqueous humor diffusion member 1002 (e.g., the first and / or second constrictive diffusion membranes 1200 and 1300). In some such embodiments, one or more portions of the folded portion of the proliferative diffusion membrane 1100 are bonded or welded to adjacent portions of the unfolded portion of the proliferative diffusion membrane 1200 and / or one or more portions of the constrictive diffusion membrane portion of the aqueous humor diffusion member 1002. 2A and 2B includes separate and distinct first and second constrictive diffusion membranes 1200 and 1300, it should be understood that the aqueous humor diffusion member 1002 can include the first constrictive diffusion membrane 1200 without the need for the separate and distinct second constrictive diffusion membrane 1300. For example, the first constrictive diffusion membrane 1200 can be folded upon itself to form a multi-layered constrictive diffusion membrane, with one or more portions of the folded portion of the constrictive diffusion membrane 1200 being bonded or welded to an adjacent portion of the unfolded portion of the constrictive diffusion membrane 1200. Additionally, the proliferative diffusion membrane 1100 may be further folded around the folded constricting diffusion membrane 1200, which is folded onto itself with a fluid conduit 1500 located between the folded and unfolded portions of the constricting diffusion membrane 1200. In some such embodiments, a reservoir may be defined between at least the folded and unfolded portions of the constricting diffusion membrane 1200.

[0071] 3 is an exploded view of the glaucoma drainage system 1000 shown in FIGS. 2A and 2B. As shown in FIG. 3, the aqueous humor diffusion member 1002 includes a body defined by a first proliferative diffusion membrane 1100, a first constrictive diffusion membrane 1200, a second constrictive diffusion membrane 1300, and a second proliferative diffusion membrane 1400. As shown, the various proliferative diffusion membranes and constrictive diffusion membranes each include an interface surface and a periphery. For example, the first proliferative diffusion membrane 1100 includes a first interface surface 1102, a second interface surface 1104, and a periphery 1106. In some instances, the first interface surface 1102 of the first proliferative diffusion membrane 1100 corresponds to or otherwise defines the outer surface 1004 of the glaucoma drainage system 1000. 3, the first constricting diffusion membrane 1200 includes a first interface surface 1202, a second interface surface 1204, and a periphery 1206. Similarly, as shown in FIG. 3, the second constricting diffusion membrane 1300 includes a first interface surface 1302, a second interface surface 1304, and a periphery 1306. As shown, the second proliferative diffusion membrane 1400 includes a first interface surface 1402, a second interface surface 1404, and a periphery 1406. In some examples, the second interface surface 1404 of the second proliferative diffusion membrane 1400 corresponds to or otherwise defines the second outer surface 1006 of the glaucoma drainage system 1000.

[0072] In various embodiments, the diffusion films (i.e., the proliferative diffusion film and the constrictive diffusion film) forming the aqueous humor diffusion member 1002 are arranged adjacent to one another in a stacked configuration. For example, as shown in Figures 2A, 2B, and 3, the first and second proliferative diffusion films 1100 and 1400 and the first and second constrictive diffusion films 1200 and 1300 are arranged adjacent to one another in a stacked configuration, with the first and second proliferative diffusion films 1100 and 1400 forming or otherwise defining the exterior of the aqueous humor diffusion member 1002 and the first and second constrictive diffusion films 1200 and 1300 being sandwiched or otherwise disposed between the first and second proliferative diffusion films 1100 and 1400. In this manner, the proliferative diffusion membrane forming the outer region of the aqueous humor diffusion member 1002 is configured to support or allow tissue in-growth and attachment, while the constrictive diffusion membrane forming the inner region of the aqueous humor diffusion member 1002 is configured to minimize, resist, or prevent tissue in-growth and attachment across or into the boundary or interface between the proliferative diffusion membrane and the constrictive diffusion membrane.

[0073] By minimizing, resisting, or preventing tissue ingrowth and adhesion across or into the constrictive diffusion membrane, the glaucoma drainage system 1000 minimizes, resists, or prevents tissue ingrowth into the reservoir 1010, which helps maintain the performance of the glaucoma drainage system during and after biointegration. For example, by minimizing, resisting, or preventing tissue ingrowth into the constrictive diffusion membrane, the reservoir 1010 thus operates to maintain the flexibility of the glaucoma drainage system 1000, which helps minimize relative movement between the glaucoma drainage system 1000 and the surrounding tissue, as discussed herein, and thus helps minimize irritation of the surrounding tissue. In particular, minimizing, resisting, or preventing tissue ingrowth into the stenotic diffusive membranes helps to avoid tissue proliferation beyond the interface between adjacent stenotic diffusive membranes, and thus helps to prevent such tissue ingrowth from interlocking the stenotic diffusive membranes. Preventing interlocking of the stenotic diffusive membranes helps to maintain the ability of the stenotic diffusive membranes to slide and move relative to one another, which helps to maintain the flexibility of the glaucoma drainage system 1000.

[0074] In some instances, as discussed further below, the aqueous humor diffusion membrane 1002 is configured so that the interface surfaces of adjacently positioned diffusion membranes face each other. In some instances, the first and second proliferative diffusion membranes 1100 and 1400 and the first and second constrictive diffusion membranes 1200 and 1300 are oriented so that their peripheries are aligned and / or coaxial with each other. In some embodiments, one or more peripheries of the diffusion members forming the main body of the aqueous humor diffusion member 1002 form the periphery 1008 of the aqueous humor diffusion member 1002. For example, as shown in FIGS. 2A and 2B , peripheries 1106, 1206, 1306, and 1406 collectively form or define the periphery 1008 of the aqueous humor diffusion member 1002. However, it should be understood that the periphery of the aqueous humor diffusion member 1002 may be formed from fewer than all of the peripheries of the diffusion membranes forming the main body of the aqueous humor diffusion member 1002. For example, in some instances, the periphery 1008 of the aqueous humor diffusion member 1002 can be formed or defined by the peripheries 1106 and 1406 of the first and second proliferative diffusion membranes 1100 and 1400 .

[0075] As described above, in various embodiments, adjacently disposed diffusion membranes are generally positioned adjacent to or otherwise oriented such that one or more of their interface surfaces are adjacent to or face the interface surface of the adjacently disposed diffusion membrane. That is, in various embodiments, the interface surfaces of adjacently disposed diffusion membranes face each other. In the embodiment shown in FIGS. 2A, 2B, and 3, the first proliferative diffusion membrane 1100 and the first constricting diffusion membrane 1200 are positioned adjacent to each other such that the second interface surface 1104 of the first proliferative diffusion membrane 1100 faces the first interface surface 1202 of the first constricting diffusion membrane 1200. Similarly, as shown in FIGS. 2A, 2B, and 3, the first constricting diffusion membrane 1200 and the second constricting diffusion membrane 1300 are positioned adjacent to each other such that the second interface surface 1204 of the first constricting diffusion membrane 1200 faces the first interface surface 1302 of the second constricting diffusion membrane 1300. Similarly, as shown in Figures 2A, 2B, and 3, the second constricting diffusion membrane 1300 and the second proliferative diffusion membrane 1400 are positioned adjacent to each other such that the second interface surface 1304 of the second constricting diffusion membrane 1300 faces the first interface surface 1402 of the second proliferative diffusion membrane 1400.

[0076] Thus, in some embodiments, the stack configuration as described above provides a first diffusion film having first and second interface surfaces and a second diffusion film having first and second interface surfaces, wherein the first and second diffusion films are adjacently positioned such that the second interface surface of the first diffusion film faces the first interface surface of the second diffusion film.

[0077] In various embodiments, the first and second proliferative diffusion membranes 1100 and 1400 and the first and second constrictive diffusion membranes 1200 and 1300 can include or be formed from one or more layers or sheets of expanded polytetrafluoroethylene (ePTFE) or other polymers, such as, but not limited to, polyurethane, polysulfone, polyvinylidene fluoride or polyvinylidene fluorine (PVDF), polyhexafluoropropylene (PHFP), perfluoroalkoxy polymer (PFA), polyolefin, fluorinated ethylene propylene (FEP), acrylic copolymers, and other suitable fluorocopolymers. These polymers can be in the form of sheets, knits, or woven fabrics (including individual or multi-fiber strands), or in porous nonwoven fabrics. In some instances, one or more of the first and second proliferative diffusion membranes 1100 and 1400 and / or the first and second constrictive diffusion membranes 1200 and 1300 may be formed from multiple layers or sheets of polymeric material. In some such instances, the layers or sheets of polymeric material may be laminated or otherwise mechanically bonded together, such as by heat treatment and / or high pressure compression and / or adhesives and / or other lamination methods known to those skilled in the art. In some embodiments, as described in more detail below, layers of polymeric material may be bonded together at distinct locations to form stabilizing structures extending through the resulting proliferative and / or constrictive diffusion membranes. Similarly, in some embodiments, as described in more detail below, proliferative and / or constrictive diffusion membranes may be bonded together at distinct locations to form stabilizing structures extending through the resulting aqueous humor diffusion member 1002. As discussed above, it should be appreciated that such stabilizing structures are operable to constrain the shape or profile of the aqueous humor diffusing member 1002 upon expansion or dilation of the reservoir 1010 .

[0078] In some embodiments, the layers or sheets of polymeric material forming the first and / or second proliferative diffusion membranes 1100 and 1400 and / or the first and / or second constrictive diffusion membranes 1200 and 1300 can be subjected to one or more processes before or after processing to modify their microstructure (and, therefore, their material properties) to increase or decrease the natural permeability (e.g., aqueous humor permeability) of the polymeric material. In some examples, such processes include, but are not limited to, a material coating process, a surface preconditioning process, and / or a perforation process. As will be appreciated by those skilled in the art, a material coating process can be utilized to at least partially fill the porous spaces of the polymeric material, thereby reducing permeability. Additionally or alternatively, a material coating process can be used to apply one or more drug or antimicrobial coatings (e.g., metal salts such as silver carbonate) to the surface of the polymeric material and organic compounds (e.g., chlorhexidine diacetate) to the polymeric material.

[0079] In some embodiments, one or both of the first and second proliferative diffusion membranes 1100 and 1400 and / or one or both of the first and second constrictive diffusion membranes 1200 and 1300 can be hydrophilic. In some embodiments, one or both of the first and second proliferative diffusion membranes 1100 and 1400 and / or one or both of the first and second constrictive diffusion membranes 1200 and 1300 are hydrophobic. Thus, in some examples, the aqueous humor diffusion member 1002 can include one or more hydrophilic membranes and one or more hydrophobic membranes.

[0080] Thus, hydrophilic coatings that allow wetting of the polymer matrix may be applied when the polymer surface is inherently hydrophobic. Surface coatings containing antioxidant components may be applied to mitigate the body's naturally occurring inflammatory response during postoperative wound healing. To mitigate the response of surrounding tissues in the eye, surfaces can be modified with antiproliferative compounds (e.g., mitomycin C, 5-fluoracil). In some instances, one or more surface preconditioning processes, as described in U.S. Patent No. 9,849,629 to Zagl et al., can additionally or alternatively be utilized to form layers exhibiting favorable microstructures (e.g., wrinkles, folds, or other geometric out-of-plane structures). Such surface preconditioning can promote a more aggressive early inflammatory phase after surgery and provide an early, stable interface between the porous device and tissue. In some instances, heparin coatings (e.g., thrombosis-resistant) can additionally or alternatively be applied to help minimize or reduce cell formation, including fibrinogen accumulation, after surgical implantation procedures.

[0081] In some embodiments, in addition to the perforations or pores naturally occurring in the polymeric material, one or more perforation processes can additionally or alternatively be utilized to form multiple perforations or pores in the polymeric material, which operates to increase the natural permeability (e.g., permeability to aqueous humor) of the polymeric material. Such perforation processes can increase the number of perforations or pores present in the polymeric material and / or increase the average size of the perforations or pores present in the polymeric material, and can occur before and / or after the formation of the proliferative and / or constrictive diffusion membranes. In some embodiments, the permeability of the first and / or second proliferative diffusion membranes 1100 and 1400 and / or the first and second constrictive diffusion membranes 1200 and 1300 can be altered to adjust or otherwise alter aqueous humor flux and / or flow resistance to a desired amount.

[0082] In various embodiments, the first and / or second proliferative diffusion membranes 1100 and 1400 can include perforations or pores ranging in size (or average size) from 20 microns to 100 microns. In other examples, the size (or average size) of the perforations or pores of the first and / or second proliferative diffusion membranes 1100 and 1400 can be greater than 150 microns. In various embodiments, the first and / or second proliferative diffusion membranes 1100 and 1400 can include perforations or pores less than 20 microns but greater than 1 or 2 microns, since perforations or pores smaller than 1 or 2 microns generally inhibit, resist, or otherwise prevent ingrowth of ducts and other tissue.

[0083] Thus, in various embodiments, the first and second constrictive diffusion membranes 1200 and 1300 are configured or selected so that the size (average size) of the perforations or pores therein is generally less than 1 or 2 microns, minimizing, resisting, or preventing tissue ingrowth and adhesion while maintaining aqueous humor permeability.

[0084] It should be understood that the first and second proliferative diffusion membranes 1100 and 1400 can be configured to have the same or different permeabilities. Similarly, it should be understood that the first and second constrictive diffusion membranes 1200 and 1300 can be configured to have the same or different permeabilities. In some instances, the various proliferative and constrictive diffusion membranes discussed herein can have the same inherent permeability but can undergo one or more of the material modification processes discussed herein to achieve different relative permeabilities. In some embodiments, one or more of the material modification processes discussed herein operate to modify or otherwise change the naturally occurring permeability of the polymeric material. Thus, in some embodiments, the permeability of the proliferative and / or constrictive diffusion membranes can be based on the naturally occurring microstructure of the polymeric material and / or one or more of the material modification processes discussed herein. Those skilled in the art will understand that permeability generally relates to the resistance of a fluid to transport through the pore space of a porous medium, with materials associated with low permeability exhibiting greater flow resistance than materials with higher permeabilities.

[0085] In some embodiments, the perforations or pores in the proliferative and constrictive diffusion membranes may be formed by one or more salt incorporation processes or by using one or more of drilling, die punching, needle punching, or laser cutting processes, which may occur before and / or after the formation of the proliferative and / or constrictive diffusion membranes.

[0086] In general, the above processes can be used to form proliferative diffusion membranes with a microstructure that allows the ingrowth of surrounding vessels and other tissues and is permeable to aqueous humor. Similarly, the above processes can be used to form constrictive diffusion membranes with a microstructure that minimizes, resists, or prevents the ingrowth of surrounding vessels and other tissues, but is permeable to aqueous humor. Aqueous humor that permeates and / or diffuses across the constrictive and proliferative diffusion membranes can be absorbed into vessels grown within the proliferative diffusion membrane and / or vessels external to the aqueous humor diffusing member 1002, and / or can permeate through the surrounding tissue into the tear film.

[0087] As mentioned above, in some embodiments, the pressure differential observed between the reservoir 1010 of the glaucoma drainage system 1000 and the environment external to the glaucoma drainage system 1000 (e.g., atmospheric pressure) is the mechanism that facilitates the flow of aqueous humor through the aqueous humor diffusing member 1002 of the glaucoma drainage system 1000. In some embodiments, the mechanism of reabsorption and transport of the drained aqueous humor by the conduits grown in and around the glaucoma drainage system 1000 facilitates the drainage of aqueous humor from the anterior chamber.

[0088] It should be appreciated, however, that in addition to promoting the reabsorption and transport of drained aqueous humor, the ingrowth of tissue, ducts, and cells into the proliferative diffusion membrane of the aqueous humor diffusing member 1002 also helps to prevent, reduce, minimize, or limit the onset of a foreign body tissue reaction. Specifically, as described above, the tissue ingrowth and attachment helps to minimize relative movement between the glaucoma drainage system 1000 and the ocular tissue. By helping to minimize such relative movement, the glaucoma drainage system 1000 helps to avoid ocular tissue irritation that can occur and lead to a foreign body tissue reaction that can cause excessive scarring and / or erosion of the glaucoma drainage system 1000 and site infection.

[0089] In some embodiments, one or more adjacently disposed diffusing films forming the body of the aqueous humor diffusing member 1002 are joined or otherwise bonded together. In some embodiments, adjacently disposed diffusing films are bonded at one or more distinct portions or regions along their adjacently opposing interfacial surfaces. In some embodiments, adjacently disposed diffusing films may be bonded along at least a portion of an adjacent edge(s). In other embodiments, adjacently disposed diffusing films may additionally or alternatively be bonded at one or more distinct locations along adjacent surfaces inside an edge(s). In still other embodiments, adjacently disposed diffusing films may be bonded along the entirety of their adjacently opposing interfacial surfaces (e.g., by applying adhesive to the entire surface area of ​​the adjacently opposing interfacial surfaces). Thus, in some embodiments, one or more adjacently disposed diffusing films may be bonded over less than all of their adjacently opposing interfacial surfaces (e.g., at distinct locations or portions thereof), or may be bonded along the entire opposing interfacial surfaces.

[0090] In embodiments in which adjacently disposed diffusion films are bonded along less than all of their adjacently opposing interfacial surfaces, one or more distinct locations along the adjacently opposing interfacial surfaces are joined or otherwise bonded, while one or more other distinct locations along the adjacently opposing interfacial surfaces are not joined or otherwise bonded, i.e., in some embodiments, at least one region or area of ​​the adjacently opposing interfacial surfaces is intentionally left unattached, unjoined, or otherwise unbonded.

[0091] In some such embodiments, these non-bonded regions or areas can include regions or areas that are central relative to the periphery. Generally, these non-bonded regions or areas can move or slide freely relative to one another and separate relative to one another to serve as reservoirs for the accumulation of drained aqueous humor. In various examples, providing such degrees of freedom (e.g., in shear) provides significant flexibility because the diffusing membranes can move relative to one another to accommodate changes in curvature as the aqueous humor diffusing member 1002 flexes and moves, as occurs during natural eye movement. Thus, discontinuities in the diffusing membrane bonds provide a glaucoma drainage system 1000 that exhibits better ocular conformance and is better suited to dynamically responding to changes in the curvature of the eye 2000 as a patient blinks, focuses, and moves their eye in the orbit. Unlike more rigid conventional designs, the increased flexibility also minimizes movement of the glaucoma drainage system 1000 relative to surrounding tissue.

[0092] 4A-4D, examples of interface surfaces including bonded and non-bonded (e.g., bonded and non-bonded) regions are shown. FIG. 4A is a cross-sectional view of the second interface surface 1204 taken along the boundary (4-4, FIG. 2) located between adjacently opposing first and second interface surfaces 1204 and 1302, with the fluid conduit 1500 removed for clarity. As discussed above, in some embodiments, adjacently opposing interface surfaces can be bonded to one another at multiple distinct locations such that the adjacently opposing interface surfaces include bonded and non-bonded regions. FIG. 4A shows the second interface surface 1204 of the first constricting diffusion membrane 1200, which includes a bonded region 1210 (shown as a cross-hatched region) that is bonded to the adjacently opposing first interface surface 1302 of the second constricting diffusion membrane 1300, in addition to bonding along the periphery 1206. As shown in Figure 4A, the second interface surface 1204 of the first constricting diffusive membrane 1200 also includes a non-bonded region 1208 (shown as the region between and around the cross-hatched region), where the second interface surface 1204 is adjacent to, but not bonded to, the adjacent opposing first interface surface 1302 of the second constricting diffusive membrane 1300. In this illustrated example of Figure 4A, the adjacent opposing first and second interface surfaces 1204 and 1302 are free to slide and move relative to each other along the non-bonded region 1208. Furthermore, these non-bonded regions 1208 are free to separate from each other to form reservoirs 1010 for the accumulation of aqueous humor.

[0093] It should be appreciated that the unbonded regions 1208 between the first and second constrictive diffusive membranes 1200 and 1300 shown in Figures 4A-4D are configured to be free to separate from one another to form the reservoir 1010, while the bonded regions 1210 remain bonded. In various examples, these bonded regions 1210 operate to control the profile of the glaucoma drainage system 1000 as the reservoir 1010 expands or dilates.

[0094] Figure 4B is a cross-sectional view of second interface surface 1204 taken along the boundary (4-4, Figure 2) located between adjacently opposing first and second interface surfaces 1204 and 1302. Figure 4B shows an alternative configuration in which second interface surface 1204 includes a centrally located bonding region 1210 (shown as a cross-hatched region) in which second interface surface 1204 is bonded to adjacently opposing first interface surface 1302 of second constricting diffusive membrane 1300 in addition to being bonded along peripheral edge 1206. Although not shown, it should be understood that the bonding configurations of Figures 4B and 4A can be combined in whole or in part.

[0095] 4C shows another configuration in which the second interface surface 1204 includes a peripherally disposed bonding region 1210 (shown as a cross-hatched region) and is bonded to an adjacent, opposing first interface surface 1302 of a second constricting diffusive membrane 1300. Although not shown, it should be understood that the bonding configurations of FIGS. 4C, 4B, and / or 4A can be combined in whole or in part.

[0096] FIG. 4D illustrates another alternative configuration in which the second interface surface 1204 includes a peripherally located bonded region 1210 and a concentric annular inner bonded region 1210 (both shown as cross-hatched regions), with the second interface surface 1204 bonded to the adjacent, opposing first interface surface 1302 of the second constrictive diffusive membrane 1300. The configuration illustrated in FIG. 4D incorporates the possibility of two distinct reservoirs for the accumulation of aqueous humor. The first reservoir corresponds to the radially inner, non-bonded portion 1208 of the concentric annular inner bonded region 1210, radially inward of the peripherally located bonded region 1210 near the periphery 1206. The second reservoir corresponds to the peripherally located, non-bonded portion 1208, located between the concentric annular inner bonded region 1210 and the peripherally located bonded region 1210. It should be understood that the first fluid conduit in the configuration illustrated in FIG. 4D is fluidly coupled to the first reservoir, while the second fluid conduit is coupled to the second reservoir. Alternatively, a single fluid conduit may be fluidly coupled to both the first and second reservoirs shown in Figure 4D, such as by corresponding openings in the fluid conduits. In another alternative, less than all of the concentric annular inner coupling region 1210 may be decoupled such that the first and second reservoirs are fluidly coupled. Although not shown, it should be understood that the coupling configurations of Figures 4D, 4C, 4B, and / or 4A may be combined in whole or in part.

[0097] 4A-4D illustrate exemplary bonded and non-bonded (e.g., bonded and non-bonded) regions of second interfacing surface 1204, it should also be understood that adjacently opposing first interfacing surface 1302 includes bonded and non-bonded regions that respectively correspond to the bonded and non-bonded regions of second interfacing surface 1204. It should further be understood that the exemplary embodiments of Figures 4A-4D should not be construed as limiting the present disclosure to the illustrated embodiments. Instead, one skilled in the art will understand that virtually any pattern of bonded and non-bonded regions can be utilized without departing from the spirit or scope of the present disclosure.

[0098] The boundary between the first proliferative diffusion membrane 1100 and the first constricting diffusion membrane 1200 is not shown, but it should be understood that the adjacent, opposing first and second interface surfaces 1202 and 1104 may be uniformly bonded across the boundary or may be bonded in accordance with the embodiments described above. Similarly, the boundary between the second proliferative diffusion membrane 1400 and the second constricting diffusion membrane 1300 is not shown, but it should be understood that the adjacent, opposing first and second interface surfaces 1402 and 1304 may be uniformly bonded across the boundary or may be bonded in accordance with the embodiments described above.

[0099] As previously mentioned, adjacent diffusion films can be connected or bonded to one another by one or more heat treatment processes and / or one or more bonding agents, such as one or more adhesives. In some embodiments, adjacently disposed diffusion films and / or layers of materials forming the diffusion films are partially or fully bonded by thermal methods when each material is at or above its melting temperature. In some embodiments, such thermal processes promote the formation of adhesive or cohesive bonds between the polymeric materials or layers of polymeric materials. In some embodiments, adjacently disposed diffusion films forming the diffusion films are partially or fully bonded by thermal methods when at least one of the materials is at or above its melting temperature. In some embodiments, such thermal processes promote the formation of adhesive or cohesive bonds between the materials or layers of materials. In some embodiments, one or more suitable adhesives are utilized to provide a well-bonded interface, which can be continuous or discontinuous.

[0100] As described above, in various embodiments, the glaucoma drainage system 1000 is operable or otherwise configured to drain aqueous humor from the anterior chamber (AC) of the eye. In some embodiments, the glaucoma drainage system 1000 includes a fluid conduit 1500, as shown in at least FIG. 1 . In various embodiments, the fluid conduit 1500 is a conformable tubular structure (e.g., a catheter) that extends into the aqueous humor diffusing member 1002 and fluidly couples the aqueous humor diffusing member 1002 to the anterior chamber of the eye. The fluid conduit 1500 provides for the outflow of fluid from the anterior chamber. As shown in FIG. 3 , the fluid conduit 1500 includes a first end 1502 and a second end 1504, and a lumen extending from the first end 1502 to the second end 1504. In general, the fluid conduit 1500 can be formed from silicone, ePTFE, polycarbonate, polyethylene, polyurethane, polysulfone, PVDF, PHFP, PFA, polyolefin, FEP, acrylic copolymers and other suitable fluorocopolymers, either alone or in combination, or from other biocompatible polymers suitable for forming a compliant fluid conduit 1500.

[0101] In some embodiments, the fluid conduit 1500 is formed by a tubular melt extrusion process. In some embodiments, the extruded fluid conduit 1500 can be drawn down to the final target dimensions. In some embodiments, the fluid conduit 1500 is formed via a tubular paste extrusion and expansion (stretching) process commensurate with producing the desired wall thickness, porosity, stiffness, and / or dimensions. In some embodiments, the fluid conduit 1500 is formed by one or more tape wrapping processes in which tape is wrapped around a mandrel of specified dimensions and cross-section. In some embodiments, the wrapped tape can be further bonded to itself by one or more thermal or adhesive methods before or after removal from the mandrel. In various embodiments, the wrapped tape configuration (e.g., ePTFE) provides a fluid conduit 1500 structure with different layers having different porosities. For example, an inner wrapped layer can be more porous than an outer wrapped layer. In some embodiments, the fluid conduit 1500 is formed by successively dip-coating materials onto an appropriately sized mandrel, then removing the solvent from the formed fluid conduit 1500 and withdrawing the mandrel.

[0102] In some embodiments, the diameter of the lumen of the fluid conduit 1500 is sufficient to allow the flow of aqueous humor through the fluid conduit 1500 from the anterior chamber to the aqueous humor diffusion member 1002, but does not result in the fluid conduit 1500 having an outer diameter that significantly inhibits or impairs normal eye function (e.g., does not interfere with blinking or regular eye movements).

[0103] As described above, the fluid conduit 1500 fluidly couples the aqueous humor diffusing member 1002 to the anterior chamber of the eye so that aqueous humor can be drained from the anterior chamber and delivered to the aqueous humor diffusing member 1002, and particularly to a reservoir defined within an interior region of the aqueous humor diffusing member 1002. Thus, the fluid conduit 1500 is configured to extend between the anterior chamber of the eye and a location in the eye to which the aqueous humor diffusing member 1002 is attached or otherwise integrated. In some embodiments, the length of the fluid conduit 1500 can be between 1 mm and 30 mm, although typically the length of the fluid conduit 1500 is oversized (or longer than necessary) to allow a physician to trim the length to the specific length required for a patient's unique anatomy. However, in various embodiments, the lumen length and diameter of the fluid conduit 1500 are preselected to control the pressure drop across the length to minimize the risk of hypotension (e.g., dangerously low intraocular pressure), since the pressure drop across the fluid conduit 1500 is a function of the length of the fluid conduit 1500. In some embodiments, the fluid conduit 1500 may be pre-marked with a cut-off length identifier corresponding to the theoretically expected pressure drop when implanted. Such a configuration gives the physician the option to custom-tune the pressure drop to the patient's particular needs. In such embodiments, after trimming the fluid conduit 1500 to a length corresponding to the desired pressure drop, the physician optionally advances the first end 1502 of the fluid conduit 1500 further into the anterior chamber or positions the aqueous humor diffusion member 1002 within the anterior chamber (e.g., further around the eye) from the point of penetration of the fluid conduit 1500 into the anterior chamber to accommodate the desired length.

[0104] In various embodiments, the fluid conduit 1500 may be porous or non-porous, or may include a combination of porous and non-porous portions. For example, in some embodiments, the fluid conduit 1500 may have a length defined by a first portion (or region) and a second portion (or region). In some embodiments, the first portion may be a non-porous portion and the second portion may be a porous portion. In some embodiments, the non-porous portion is impermeable to aqueous humor, while the porous portion is permeable to aqueous humor. Thus, in some embodiments, aqueous humor drained from the anterior chamber by the fluid conduit 1500 may permeate through the porous portion of the fluid conduit 1500. For example, the portion of the fluid conduit 1500 within the anterior chamber may have an outer surface that is impermeable to aqueous humor or cellular infiltration, while the portion of the fluid conduit 1500 outside the anterior chamber may allow or otherwise enable cellular infiltration and tissue ingrowth and biointegration. In some embodiments, the interior surface of the fluid conduit 1500 can be impermeable to aqueous humor and is configured to minimize bacterial ingress and ingrowth of conduits and tissue structures.

[0105] In some embodiments, the porous portion of the fluid conduit 1500 may be formed by subjecting a region (e.g., a portion of the length of the fluid conduit 1500) to one or more of the perforation processes described above to form multiple perforations in the region of interest. However, the fluid conduit 1500 need not include a portion that is permeable to aqueous humor.

[0106] In general, the flow of aqueous humor through the glaucoma drainage system 1000 is governed by the pressure difference between intraocular pressure and the pressure within the aqueous humor diffusing member 1002 (which is a function of forces acting on the aqueous humor diffusing member 1002, such as atmospheric pressure). The pressure difference between these pressure regions causes aqueous humor to flow from the anterior chamber into the glaucoma drainage system 1000. In some embodiments, the rate at which aqueous humor flows through the glaucoma drainage system 1000 is governed by this pressure difference and the resistance to flow. In some embodiments, the resistance to flow is a function of the fluid conduit flux resistance (e.g., based on tubing geometry, diameter, and length, generally based on the Hagen-Poiseuille equation) and the resistance to aqueous humor flux through the aqueous humor diffusing member 1002, as would be understood by one of ordinary skill in the art. In some embodiments, as discussed above, the resistance to aqueous humor flux through the aqueous humor diffusing member 1002 can be controlled by the permeability of the underlying material forming the aqueous humor diffusing member 1002.

[0107] As described above, the fluid conduit 1500 is a soft, malleable, biocompatible tubular structure. In some embodiments, the fluid conduit 1500 is malleable in that it exhibits low column strength and is generally unable to support its own weight. That is, in some embodiments, the fluid conduit 1500 lacks a sufficient amount of structural integrity (e.g., compressive hoop strength) necessary to avoid collapse under its own weight (e.g., collapse of an inner lumen extending through the fluid conduit 1500).

[0108] In some embodiments, intraocular pressure in the anterior chamber distends or otherwise acts to maintain the generally tubular geometry of the fluid conduit 1500 (e.g., avoiding collapse of the lumen 1506A). That is, in some embodiments, aqueous humor flowing through the lumen of the fluid conduit 1500 acts to distend the lumen. Such a configuration provides a soft, flexible fluid conduit 1500 that conforms to the curvature of the eye and avoids interfering with normal eye function (e.g., rotation and blinking). It should be understood that in some embodiments, the fluid conduit 1500 may instead be constructed to exhibit a sufficient amount of structural integrity to maintain its generally tubular geometry and / or avoid collapse of the lumen.

[0109] Referring again to FIG. 3 , in some embodiments, the fluid conduit 1500 includes a first end 1502 and an opposite second end 1504. In some embodiments (not shown in FIG. 3 ), the fluid conduit 1500 includes a lumen extending from the first end 1502 to the second end. In some embodiments, the first end 1502 is insertable into the anterior chamber, and the second end 1504 is inserted into or otherwise attached to the aqueous humor diffusing member 1002. In some embodiments, the first end 1502 is positionable within the anterior chamber such that the first end 1502 extends into an interior region of the anterior chamber.

[0110] In some embodiments, after the first end 1502 of the fluid conduit 1500 is placed in the anterior chamber, the fluid conduit 1500 can be secured to prevent removal of the fluid conduit 1500 from the anterior chamber. In some embodiments, one or more sutures are utilized to attach the fluid conduit 1500 and / or the aqueous humor diffusion member 1002 to ocular tissue. In some embodiments, a biocompatible tissue adhesive is used to bond the fluid conduit 1500 and / or the aqueous humor diffusion member 1002 to surrounding or adjacent tissue. In some embodiments, a needle track created through tissue prior to placement of the fluid conduit 1500 can be sized to provide sufficient interfacial fit with the fluid conduit 1500 along the length of the needle track. In some embodiments, the first end 1502 of the fluid conduit 1500 can additionally or alternatively be flared to a larger diameter than other portions (e.g., a central portion) of the fluid conduit 1500 (or the lumen within the tissue through which the fluid conduit 1500 extends), creating an interference attachment that helps maintain placement of the first end 1502 within the anterior chamber of the eye. In some instances, the flared first end 1502 of the fluid conduit 1500 helps prevent the fluid conduit 1500 from becoming dislodged from its position within the anterior chamber.

[0111] In some embodiments, the second end 1504 of the fluid conduit 1500 is coupled to the aqueous humor diffusing member 1002 such that a reservoir defined within the aqueous humor diffusing member 1002 is fluidly coupled with the fluid conduit 1500 and, therefore, with a fluid-filled body cavity (e.g., the anterior chamber of the eye) when the glaucoma drainage system 1000 is implanted in the body. In some embodiments, the second end 1504 of the fluid conduit 1500 extends or otherwise terminates within the aqueous humor diffusing member 1002, such as between the first and second constrictive diffusion membranes 1200 and 1300 that define the reservoir. For example, as shown in FIG. 5 , the fluid conduit 1500 is coupled to the aqueous humor diffusing member 1002 such that the fluid conduit 1500 terminates within the aqueous humor diffusing member 1002. That is, in some embodiments, the second end 1504 is coupled to the aqueous humor diffusion member 1002 such that drained aqueous humor exiting the fluid conduit 1500 at the second end 1504 diffuses or otherwise enters the aqueous humor diffusion member 1002 beginning at a location interior to the periphery 1008. While not shown separated from one another in FIG. 5, it should be understood that the first and second constrictive diffusion membranes 1200 and 1300 are operable to separate from one another to allow the reservoirs to be expandable or distensible, as described above.

[0112] 5, aqueous humor traveling through the fluid conduit 1500 along arrow 1602 exits the second end 1504 of the fluid conduit 1500 and diffuses or otherwise enters the reservoir 1010. As described above, the reservoir 1010 can include the pore space of the first and second constricting diffusion membranes 1200 and 1300 and / or the area defined between the first constricting diffusion membrane 1200 and the second constricting diffusion membrane 1300. As shown in FIG. 5, aqueous humor is shown exiting the fluid conduit 1500 and entering the reservoir 1010, which includes the area defined between at least the first and second constricting diffusion membranes 1200 and 1300.

[0113] As the discharged aqueous humor permeates through the constricting diffusion membrane of the aqueous humor diffusing member 1002, the aqueous humor generally seeps outward from the aqueous humor diffusing member 1002, as indicated by arrows 1604A-1604E. It should be understood that arrows 1604A-1604E are not intended to represent the actual path of the aqueous humor, but rather to represent the aqueous humor permeating away from an interior region, such as the reservoir 1010, of the aqueous humor diffusing member 1002, or at least away from the second end 1504 of the fluid conduit 1500.

[0114] In some other embodiments, the second end 1504 of the fluid conduit 1500 is coupled to the periphery 1008 of the aqueous humor diffusing member 1002. For example, as shown in FIG. 6 , the second end 1504 of the fluid conduit 1500 is coupled to the aqueous humor diffusing member 1002 at its periphery 1008. That is, in some embodiments, the second end 1504 is coupled to the aqueous humor diffusing member 1002 such that draining aqueous humor exiting the fluid conduit 1500 at the second end 1504 diffuses or otherwise injects into the first and second constricting diffusion membranes 1200 and 1300, which begin at or near the periphery 1008 of the aqueous humor diffusing member 1002.

[0115] In some such embodiments, as the drained aqueous humor permeates through the aqueous humor diffusing member 1002, the aqueous humor can permeate toward the interior of the aqueous humor diffusing member 1002 and / or toward the exterior of the aqueous humor diffusing member 1002. In some embodiments, as described above, aqueous humor traveling through the fluid conduit 1500 exits the second end 1504 of the fluid conduit 1500 between the first and second constrictive diffusion membranes 1200 and 1300. Also as described above, the aqueous humor enters the reservoir 1010 of the aqueous humor diffusing member 1002, which can be defined between the first and second constrictive diffusion membranes 1200 and 1300, or can additionally or alternatively correspond to the pore space of the first constrictive diffusion membranes 1200 and 1300. As described above, the glaucoma drainage system 1000 is configured to allow the drained aqueous humor to permeate from the interior of the aqueous humor diffusing member 1002 toward the exterior of the aqueous humor diffusing member 1002.

[0116] Arrows 1604A-1604C in Figure 6 represent aqueous humor generally permeating the aqueous humor diffusing member 1002. As shown, arrow 1604A represents aqueous humor permeating the aqueous humor diffusing member 1002 generally toward an interior region of the aqueous humor diffusing member 1002, while arrows 1604B and 1604C represent aqueous humor permeating through the aqueous humor diffusing member 1002 generally toward the exterior of the aqueous humor diffusing member 1002. As noted above, it should be understood that arrows 1604A-1604C are not intended to represent the actual path of aqueous humor, but instead are intended to represent aqueous humor permeating at least away from the second end 1504 of the fluid conduit 1500. Although not shown separated from one another in Figure 6, it will be understood that the first and second constricting diffusion membranes 1200 and 1300 are operable to separate from one another to define the reservoir 1010 therebetween.

[0117] In various embodiments, the second end 1504 of the fluid conduit 1500 may be coupled to the periphery 1008 of the aqueous humor diffusion member 1002 by adhesive, welding, suturing, or one or more mechanical fasteners. In some embodiments, the second end 1504 of the fluid conduit 1500 may be coupled to the periphery 1008 by one or more thermal bonding methods described above to create an adhesive or cohesive bond between materials or layers of materials.

[0118] In various embodiments, the fluid conduit 1500 is coupled to the aqueous humor diffusion member 1002 such that the discharged aqueous humor exiting the fluid conduit 1500 at the second end 1504 diffuses through the constricting diffusion membrane before diffusing through the proliferative diffusion membrane. For example, as shown in Figures 5 and 6, the second end 1504 of the fluid conduit 1500 is coupled to the aqueous humor diffusion member 1002 such that the discharged aqueous humor exiting the fluid conduit 1500 at the second end 1504 diffuses through one or more of the first and second constricting diffusion membranes 1200 and 1300 before diffusing through the first and second proliferative diffusion membranes 1100 and 1400.

[0119] Unlike conventional designs, glaucoma drainage system 1000 is soft and flexible and does not require the retention of a hollow aqueous humor reservoir within its aqueous humor diffusing member 1002. Conventional permeable hollow aqueous humor reservoirs must therefore be rigid enough to retain their volume. Thus, compared to glaucoma drainage system 1000, conventional designs are relatively rigid and prone to relative movement between the tissue and the device, and therefore tissue irritation that can lead to excessive scarring and erosion of conventional devices.

[0120] As described above, in various embodiments, the aqueous humor diffusing member 1002 includes one or more adjacently disposed diffusion membranes having adjacently opposing interface surfaces that can slide or otherwise move relative to one another. In some embodiments, aqueous humor discharged from the anterior chamber and introduced into the aqueous humor diffusing member 1002 acts as a lubricant to reduce friction between such interface surfaces and further facilitate sliding or relative movement between non-bonded portions or regions. Specifically, as aqueous humor enters the aqueous humor diffusing member 1002, it permeates and diffuses across the various diffusion membranes. As aqueous humor permeates and diffuses across the diffusion membranes, some of the aqueous humor diffuses across the boundaries separating adjacently disposed diffusion membranes. In some embodiments, as aqueous humor diffuses across the boundaries, it acts as a lubricant to reduce friction between the interface surfaces of the boundaries, further increasing the flexibility of the aqueous humor diffusing member 1002.

[0121] As described above, in some embodiments, the fluid conduit 1500 is soft and flexible and generally lacks a sufficient amount of structural integrity (e.g., hoop strength) to avoid collapse under its own weight. In some embodiments, this lack of structural integrity results in deformation of the fluid conduit 1500 to the extent that the lumen extending therethrough loses a significant portion of its cross-sectional area. In some embodiments, this lack of structural integrity also causes the fluid conduit 1500 to deform to the extent that aqueous humor in the anterior chamber is significantly restricted from entering the lumen of the fluid conduit 1500. In some embodiments, to avoid these potential risks, the fluid conduit 1500 can be configured such that one or more of its ends are sufficiently structurally sound in that they are operable to maintain lumen integrity and avoid lumen collapse or significant deformation. In such embodiments, the intermediate portion of the fluid conduit 1500 located between the first and / or second ends 1502 and 1504 is generally not structurally sound in that it cannot support its own weight. For example, the end (or terminal portion) of the fluid conduit 1500 that is disposed within the anterior chamber is configured to be operable to maintain luminal integrity and avoid collapse or otherwise significant deformation of the lumen. In this example, the above-mentioned risks associated with relative movement and tissue irritation due to rigidity are generally avoided because the structurally sound end of the fluid conduit 1500 is suspended within the aqueous humor of the anterior chamber and therefore does not interact with tissue in a manner that could cause tissue irritation.

[0122] In various embodiments, the material of the fluid conduit 1500 can undergo one or more material conditioning processes to achieve structurally sound first and / or second ends. In some embodiments, one or more structural members, such as one or more stents or struts or reinforcing rings, can be incorporated into, integrated with, or bonded to the first and / or second ends 1502 and 1504 to achieve the aforementioned structural integrity. These stents, struts, and / or reinforcing rings can be formed from any suitable biocompatible metallic or polymeric material discussed herein (e.g., FEP). In some embodiments, localized densification of the first and / or second ends 1502 and 1504 of the fluid conduit 1500 can increase its structural integrity sufficiently to resist closure forces exerted on the ends by body tissue.

[0123] While the aqueous humor diffusing member 1002 shown and described herein includes a body defined by four diffusion membranes, the body of the aqueous humor diffusing member 1002 may alternatively be defined by only three diffusion membranes or more than four diffusion membranes without departing from the spirit or scope of the present disclosure. For example, while the above-described embodiments include an aqueous humor diffusing member 1002 including multiple constrictive diffusion membranes and multiple proliferative diffusion membranes, in some embodiments, the aqueous humor diffusing member 1002 includes a constrictive diffusion membrane sandwiched between multiple proliferative diffusion membranes. For example, referring now to FIGS. 7A-7B, a glaucoma drainage system 7000 is shown including an aqueous humor diffusing member 7002 defined by a first proliferative diffusion membrane 7100, a first constrictive diffusion membrane 7200, and a second proliferative diffusion membrane 7300. As shown, a first constrictive diffusion membrane 7200 is disposed between first and second proliferative diffusion membranes 7100 and 7300. The first constrictive diffusion membrane 7200 is configured to minimize, resist, or prevent tissue ingrowth and adhesion, while the first and second proliferative diffusion membranes 7100 and 7300 are configured to allow tissue ingrowth and adhesion. Figure 7A shows the glaucoma drainage system 7000 in a contracted state. Figure 7B shows the glaucoma drainage system 7000 in an inflated state, with aqueous humor present in an expandable or distensible reservoir 7010 defined between the first proliferative diffusion membrane 7100 and the first constrictive diffusion membrane 7200. Although the glaucoma drainage system 7000 is shown in FIG. 7B in an expanded state in which the glaucoma drainage system 7000 is not uniformly expanded (e.g., the first proliferative membrane 7100 adopts a generally nonlinear configuration, while the second proliferative diffusion membrane 7300 and the constrictive diffusion membrane 7200 are shown in a generally linear configuration), it should be understood that the glaucoma drainage system 7000 can be uniformly deformed (e.g., the second proliferative diffusion membrane 7300 and the constrictive diffusion membrane 7200 can deform to mirror the deformation of the first proliferative diffusion membrane 7100). A fluid conduit 7500 can be disposed between the first constrictive diffusion membrane 7200 and one of the first and second proliferative diffusion membranes 7100 and 7300. As shown, the fluid conduit 7500 is disposed between the first constrictive diffusion membrane 7200 and the first proliferative diffusion membrane 7100.The constricting diffusion membrane and the proliferative diffusion membrane may be bonded together along their entire adjacent surface area, consistent with the above discussion, or may include one or more non-bonded or unbonded areas or regions.

[0124] 7B, the first constricting diffusion membrane 7200 and the first proliferative diffusion membrane 7100 are bonded along their peripheries but include non-bonded or unbonded regions therein, defining the reservoir 7010. Thus, the non-bonded or unbonded regions between the first constricting diffusion membrane 7200 and the first proliferative diffusion membrane 7100 can separate from each other when aqueous humor enters the reservoir 7010, causing the reservoir 7010 to expand or dilate.

[0125] It should be appreciated that the configuration of the glaucoma drainage system 7000 shown in Figures 7A and 7B includes a reservoir 7010 defined between a constrictive diffusion membrane and a proliferative diffusion membrane. Such a configuration allows tissue ingrowth along one side of the reservoir and minimizes, resists, or prevents tissue ingrowth along the other side of the reservoir. Furthermore, because the constrictive diffusion membrane and the proliferative diffusion membrane are associated with different permeabilities, the drained aqueous humor will penetrate the constrictive diffusion membrane and the proliferative diffusion membrane at different rates.

[0126] In some embodiments, these different rates at which aqueous humor diffuses or penetrates different membranes can be utilized to influence, direct, or otherwise "steer" aqueous humor through the aqueous humor diffusing element. In some embodiments, the aqueous humor diffusing element can be configured to direct a greater percentage (or a greater volume) of aqueous humor toward the first outer surface of the aqueous humor diffusing element than toward the second outer surface of the aqueous humor diffusing element. Similarly, in some embodiments, the aqueous humor diffusing element can be configured to direct a portion of the aqueous humor toward the periphery of the aqueous humor diffusing element. Such a configuration can steer the drained aqueous humor toward designated areas of the surrounding tissue, such as areas of the surrounding tissue adapted to better absorb the drained aqueous humor and promote its absorption into the tear film.

[0127] For example, with continued reference to Figures 7A and 7B, in some embodiments, the first proliferative diffusion membrane 7100 has a higher flux than the first constricting diffusion membrane 7200, and therefore a higher percentage (or volume) of aqueous humor is steered toward the outer surface extending along the first proliferative diffusion membrane 7100 compared to the percentage (or volume) of aqueous humor steered toward the outer surface extending along the second proliferative diffusion membrane 7400. It should be understood that in some embodiments, such a configuration can additionally or alternatively be achieved by forming the first constricting diffusion membrane to have a higher flux than the flux of the second constricting diffusion membrane. In some embodiments, such a configuration can additionally or alternatively be achieved by forming a first proliferative diffusion membrane to have a higher flux than the flux of the second proliferative diffusion membrane. In some embodiments, such a configuration can additionally or alternatively be achieved by forming boundaries between adjacently disposed diffusion membranes such that different boundaries are associated with different fluxes. The different boundaries associated with the different fluxes can be achieved by the way adjacently positioned diffusion films are adhered or bonded to one another.

[0128] 7A and 7B includes a fluid conduit 7500 disposed between a first proliferative diffusion membrane 7100 and a first constricting diffusion membrane 7200, and a reservoir 7010 defined between the first proliferative diffusion membrane 7100 and the first constricting diffusion membrane 7200, it should be understood that the first constricting diffusion membrane may be formed from multiple laminated layers of polymer material (as described above), and the fluid conduit 7500 may be disposed between adjacent layers of polymer material. Additionally or alternatively, in some instances, one or more adjacent, opposing layers of polymer material forming the constricting membrane may include one or more non-bonded, non-bonded, or non-laminated areas or regions, consistent with the discussion above, whereby the non-bonded, non-bonded, or non-laminated areas or regions of adjacent, opposing layers of polymer material may be freely separated from one another and slide or move relative to one another to at least partially define the reservoir 7010.

[0129] Although the aqueous humor diffusing members illustrated and described herein are generally thin, flat, and circular (or oval), it should be understood that the aqueous humor diffusing member may have any suitable shape without departing from the spirit or scope of the present disclosure. For example, the aqueous humor diffusing member may be square, rectangular, trapezoidal, or other polygonal, may include chamfered or rounded edges between sides, and the sides may be essentially straight or generally curved. Alternatively, the aqueous humor diffusing member may have a substantially continuous curved edge in that it is circular or oval, or another suitable shape (e.g., bean-shaped). Therefore, the embodiments and examples contained herein should not be construed as limiting, and one skilled in the art will understand that the aqueous humor diffusing member may have any desired shape, so long as it serves to adequately contain the discharged aqueous humor and promote its reabsorption, thereby providing effective treatment for the patient.

[0130] In some alternative embodiments, the aqueous humor diffusing member can have a tubular or cylindrical profile including multiple concentrically arranged diffusion membranes. For example, the aqueous humor diffusing member can include a tubular constrictive diffusion membrane and a tubular proliferative diffusion membrane, where the tubular constrictive diffusion membrane corresponds to an inner diffusion membrane concentric with the proliferative diffusion membrane, and the proliferative diffusion membrane defines the exterior of the aqueous humor diffusing member. Referring now to FIG. 8 , a glaucoma drainage system 8000 is shown including an aqueous humor diffusing member 8002 defined by an outer tubular proliferative diffusion membrane 8100 concentric with an inner tubular constrictive diffusion membrane 8200. A portion of the aqueous humor diffusing member 8002 is shown cut away to expose the interior region of the aqueous humor diffusing member 8000. As shown, a reservoir 8010 is defined within the central lumen of the inner tubular constricting diffusion membrane 8200, and a fluid conduit 8500 is fluidly coupled to the reservoir 8010 at the second end 8006 of the aqueous humor diffusion member 8002. In some embodiments, the concentric diffusion membranes of the aqueous humor diffusion member 8002 shown in FIG. 8 can be uncoupled or partially uncoupled from one another, as discussed herein. In some embodiments, at least one end of the aqueous humor diffusion member 8002 (e.g., the first end 8004 opposite the fluid conduit 8500) is sealed to allow drained aqueous humor to permeate through the concentric diffusion membranes of the aqueous humor diffusion member 8002.

[0131] As described above, in various embodiments, the fluid conduit is a flexible, malleable tubular member insertable into the anterior chamber of the eye. Generally, regardless of the particular surgical approach employed by the physician, one or more of the fluid conduits and aqueous humor diffusion members are advanced or pushed during the implantation procedure. Soft, thin, malleable tubular structures are generally difficult to advance through tissue. Accordingly, in various embodiments, the glaucoma drainage systems described herein can further include a stiffening member removably integrated with the glaucoma drainage system. The removable stiffening member operates with the fluid conduit to temporarily form a placement assembly having a column strength that exceeds the column strength of the fluid conduit. For example, in some embodiments, the stiffening member is disposed within the fluid conduit. In some other embodiments, the stiffening member is additionally or alternatively disposed around the fluid conduit. Treatment methods can include utilizing the stiffening member to advance one or more of the fluid conduits and aqueous humor diffusion members into position, followed by removing the stiffening member after implantation.

[0132] Additionally or alternatively, in various embodiments, the fluid conduits of the various glaucoma drainage systems discussed herein can be configured to include multiple lumens. In some embodiments, one or more lumens of a multi-lumen fluid conduit can be initially blocked, and one or more lumens of the multi-lumen fluid conduit can be unblocked postoperatively to increase the fluid flow rate through the fluid conduit. Thus, in various embodiments, the various glaucoma drainage systems described herein can include one or more mechanisms that can be postoperatively altered to increase and / or decrease the aqueous humor transmission rate per unit time of the glaucoma drainage system. Thus, the glaucoma drainage systems described herein are operable to be dynamically altered to accommodate changes in the anatomy or function of a patient's eye postoperatively, without the need for additional invasive surgery.

[0133] In some embodiments, the glaucoma drainage systems discussed herein are implanted ab-internally (e.g., from the inside of the eye), such as through a clear corneal incision, and placed through the sclera into the incised subconjunctival space, as will be understood by those skilled in the art. In other embodiments, the glaucoma drainage system can be implanted externally (e.g., from the outside of the eye), such as through a conjunctival incision, as will be understood by those skilled in the art. In some embodiments, a radial incision in the conjunctiva is made, typically near the limbal junction, and blunt dissection of the conjunctiva is performed to expose the sclera and provide a site for placement of the aqueous humor diffusion element. In some embodiments, this may require suturing the aqueous humor diffusion element to the sclera. In some embodiments, a small needle, typically a 22-gauge or 23-gauge needle, is also inserted near the scleral spine to provide a trajectory for subsequent insertion and placement of a fluid conduit into the anterior chamber.

[0134] As mentioned above, in various embodiments, the aqueous humor diffusing members discussed herein are formed from multiple diffusion membranes, including a proliferative diffusion membrane and a constrictive diffusion membrane, where the porosity or permeability to aqueous humor of the proliferative diffusion membrane exceeds the porosity of the constrictive diffusion membrane. Thus, the disclosed aqueous humor diffusing members include multiple different membranes with different degrees of porosity (e.g., different amounts of pores and / or pores of different sizes). Generally, different diffusion membranes with different porosities are associated with different rates (also referred to as fluxes) at which aqueous humor diffuses through the associated membranes. For example, an aqueous humor diffusing member may be configured such that an amount of aqueous humor diffuses through a constrictive diffusion membrane at a different rate (e.g., lower flux) than the amount of aqueous humor diffuses through a proliferative diffusion membrane (e.g., higher flux). Thus, an aqueous humor diffusing member may be configured such that aqueous humor diffuses through a first region of the aqueous humor diffusing member at a different rate than the amount of aqueous humor diffuses through a second region of the aqueous humor diffusing member.

[0135] As described above, in various embodiments, the layers of polymeric material forming the diffusion membrane can be bonded to one another at one or more distinct locations to form stabilizing structures extending through the diffusion membrane. In some embodiments, during the lamination process, the various layers forming the diffusion membrane can be laminated together such that one or more distinct pillars or columnar structures extend through the diffusion membrane from a first interface surface of the diffusion membrane to a second interface surface of the diffusion membrane. In various embodiments, these pillars or columnar structures can be formed with an adhesive. In some embodiments, one or more of these pillars can effectively leave open or otherwise maintain an effective strainable, shearable, and slidable interface so that the glaucoma drainage device is flexible and operable to accommodate drained aqueous humor. Furthermore, in some embodiments, unintended expansion (e.g., ballooning) of the aqueous humor diffusion member beyond a specified amount or beyond a specified profile can be minimized and / or avoided by individually bonding adjacently opposing interface surfaces of adjacently positioned diffusion membranes, as described above.

[0136] As described above, in various embodiments, the fluid conduits and / or body of the aqueous humor diffusion member are formed from a soft, malleable material, allowing for a structure that conforms to the curvature of the eye and helps minimize relative movement between the glaucoma drainage system and surrounding tissue, which can cause tissue irritation, foreign body tissue reaction, excessive scarring, and / or erosion. Another potential problem experienced with conventional designs includes erosion of the fluid conduits through the conjunctiva, which is typically located in close proximity to the area where the fluid conduits extend through the sclera into the anterior chamber of the eye. Such erosion of the conjunctiva can lead to direct exposure of the anterior chamber, providing a pathway for bacteria to enter the eye, risk of endophthalmitis, and potential loss of vision in the eye.

[0137] Many approaches have been attempted to minimize the likelihood of such erosion through the conjunctiva, but none of the known solutions include a single device or system that combines aqueous humor drainage with protection from erosion of the fluid conduits.

[0138] 9A-11 , in various embodiments, a glaucoma drainage system 9000 includes an aqueous humor diffusing member 9002 and a fluid conduit 9500. The fluid conduit 9500 may be consistent in structure, form, configuration, and function with the various fluid conduits described above (e.g., fluid conduit 1500). Similarly, the aqueous humor diffusing member 9002 may be consistent in structure, form, configuration, and function with the various aqueous humor diffusing members described above (e.g., aqueous humor diffusing member 1002), with the exception that the aqueous humor diffusing member 9002 further includes one or more erosion elements 9600.

[0139] In various embodiments, the erosion element 9600 is an element, feature, component, or portion of the glaucoma drainage system 9000 that covers a portion of the fluid conduit 9500 and helps minimize erosion of the fluid conduit 9500 through one or more tissues of the eye when the glaucoma drainage system 9000 is implanted. As discussed above, in various embodiments, the glaucoma drainage system 9000 is implantable within a pocket formed between the conjunctiva and sclera of the eye, as will be understood by those skilled in the art.

[0140] In some cases, for example, the erosion element 9600 extends from the body of the glaucoma drainage system 9000 to cover the fluid conduit 9500. The erosion element 9600 acts as a protective barrier between the fluid conduit 9500 and one or more surrounding tissues of the eye. For example, the glaucoma drainage system 9000 can be configured such that the erosion element 9600 extends along the fluid conduit 9500 between the fluid conduit 9500 and the conjunctiva of the eye when implanted. In some such embodiments, the erosion element 9600 helps to minimize or even prevent erosion of the fluid conduit 9500 through the conjunctiva by forming a barrier between the fluid conduit 9500 and the conjunctiva when the glaucoma drainage device 9000 is implanted in the eye, as discussed further below.

[0141] In some embodiments, the erosion element 9600 forms an integral, inseparable element, feature, component, or portion of the glaucoma drainage system 9000. In some other embodiments, the erosion element 9600 is formed as a separate element or component that is coupled to one or more portions of the glaucoma drainage system 9000. In some such embodiments, the erosion element 9600 may be coupled to one or more portions of the glaucoma drainage system 9000, thereby making it integral with the glaucoma drainage system 9000. Alternatively, in some embodiments, the erosion element 9600 may be coupled to one or more portions of the glaucoma drainage system 9000 such that the erosion element 9600 can be subsequently separated and removed from the glaucoma drainage system 9000.

[0142] As described above, the glaucoma drainage system 9000 can include multiple erosion elements 9600. In some such embodiments, the fluid conduit 9500 of the glaucoma drainage system 9000 can be isolated from interfacing with surrounding eye tissue (e.g., the sclera or conjunctiva) by incorporating multiple erosion elements 9600. That is, in some embodiments, the glaucoma drainage system 9000 can include one or more erosion elements 9600 that isolate the fluid conduit 9500 of the glaucoma drainage system 9000 from eye tissue. For example, the glaucoma drainage system 9000 can be configured such that the erosion elements 9600 are adjacent to the fluid conduit 9500 on either side of a plane that bisects the fluid conduit 9500 along its longitudinal axis. In such a configuration, for example, a first erosion element of the erosion element 9600 can extend along the fluid conduit 9500 between the fluid conduit 9500 and the sclera of the eye. Similarly, a second erosion element of the erosion element 9600 can extend along the fluid conduit 9500 between the fluid conduit 9500 and the conjunctiva of the eye. Such a configuration prevents direct interfacing of the conjunctiva and sclera of the eye when the glaucoma drainage device 9000 is implanted in the eye (e.g., when implanted in a pocket formed between the conjunctiva and the sclera), thereby providing erosion protection to both the conjunctiva and sclera of the eye.

[0143] As noted above, with the exception of the erosion element 9600, the glaucoma drainage system 9000 is similar in structure, form, and configuration to other glaucoma drainage systems discussed herein (e.g., glaucoma drainage system 1000). Thus, in various embodiments, the glaucoma drainage system 9000 includes a multi-layer structure and is configured to facilitate drainage of aqueous humor from the anterior chamber of the eye, as well as to aid in drainage of aqueous humor from the anterior chamber of the eye, for example, by promoting reabsorption of the drained aqueous humor by the body. Similar to the glaucoma drainage system 1000, in various embodiments, the glaucoma drainage system 9000 also includes one or more constrictive diffusion membranes and one or more proliferative diffusion membranes arranged to optimize aqueous humor drainage and reabsorption (see discussion above).

[0144] In various embodiments, the erosion element 9600 comprises a thin, flexible, porous membrane consistent in structure, form, and configuration with the various other thin, flexible, porous membranes discussed herein (e.g., the diffusion membranes discussed above). For example, the erosion element 9600 can include microstructures configured to resist tissue ingrowth (e.g., a constrictive diffusion membrane), or can include microstructures configured to promote or tolerate tissue ingrowth (e.g., a proliferative diffusion membrane). Alternatively, in some embodiments, the erosion element 9600 can include a multi-layer structure including a first membrane configured to promote or tolerate tissue ingrowth (e.g., a proliferative diffusion membrane) and a second membrane configured to resist tissue or cell ingrowth (e.g., a constrictive diffusion membrane). The permissive / resistant membranes in such embodiments are oriented to optimize the effectiveness of the glaucoma drainage device 9000 when implanted in an eye. For example, as described in more detail below, in various embodiments, the erosion element 9600 is configured to promote or allow tissue ingrowth along the interface between the erosion element 9600 and ocular tissue (e.g., the sclera or conjunctiva, etc.). Accordingly, it will be understood that the material of the erosion element 9600 can include any material and can be constructed according to any method discussed herein as suitable for the diffusion membrane described above.

[0145] Thus, in various embodiments, the erosion element 9600 can be coupled to (or alternatively be an extension of or integral with) any of the various proliferative diffusion membranes or constrictive diffusion membranes discussed herein. Thus, in some embodiments, the erosion element 9600 can itself be a constrictive diffusion membrane (e.g., configured to minimize, resist, or prevent tissue ingrowth) or a proliferative diffusion membrane (e.g., configured to allow tissue ingrowth). In some such embodiments, the erosion element 9600 is a constrictive diffusion membrane coupled to or integral with a constrictive diffusion membrane of an aqueous humor diffusion member. Additionally or alternatively, in some embodiments, the erosion element 9600 is a constrictive diffusion membrane coupled to a proliferative diffusion membrane of an aqueous humor diffusion member. In some embodiments, the erosion element 9600 is a proliferative diffusion membrane coupled to a constrictive diffusion membrane of an aqueous humor diffusion member. In some embodiments, the erodible element 9600 is a proliferative diffusion membrane that is coupled to or integral with the proliferative diffusion membrane of the aqueous humor diffusion member.

[0146] 9A-9C and 10, a glaucoma drainage system 9000 is shown. FIG. 9A is a top view of the glaucoma drainage system. FIG. 9B is a cross-sectional view of the glaucoma drainage system 9000 taken along line 9B-9B in FIG. 9A. FIG. 9C is a cross-sectional view of the glaucoma drainage system 9000 taken along line 9C-9C in FIG. 9A. FIG. 10 is an exploded view of the glaucoma drainage system 9000.

[0147] As shown, the glaucoma drainage system 9000 includes an aqueous humor diffusion member 9002, a fluid conduit 9500 (e.g., a shunt), and an erosion element 9600. The aqueous humor diffusion member 9002 includes multiple layers, including a first layer 9010 and a second layer 9020. The first and second layers 9010 and 9020 each include one or more diffusion membranes configured to promote or allow tissue ingrowth (e.g., proliferative diffusion membranes) and / or one or more diffusion membranes configured to resist tissue ingrowth (e.g., constrictive diffusion membranes). Thus, it will be understood that the first layer 9010 can include one or more diffusion membranes configured to promote or allow tissue ingrowth and one or more diffusion membranes configured to minimize, resist, or prevent tissue ingrowth. Similarly, it will be appreciated that the section layer 9020 may additionally or alternatively be formed from one or more diffusion membranes configured to promote or allow tissue ingrowth, and one or more diffusion membranes configured to minimize, resist, or prevent tissue ingrowth. Accordingly, it will be appreciated that the aqueous humor diffusion member 9002 may be similar in structure, form, and function to various other aqueous humor diffusion members discussed herein.

[0148] 9A-12, the glaucoma drainage system 9000 includes an erosion element 9600. The erosion element 9600 extends away from the aqueous humor diffusing member 9002 of the glaucoma drainage system 9000, as shown. In some embodiments, the erosion element 9600 extends along the fluid conduit 9500 between the aqueous humor diffusing member 9002 and the aqueous humor diffusing member 9002, away from the aqueous humor diffusing member 9002. In some embodiments, the erosion element 9600 extends between the aqueous humor diffusing member 9002 and an end of the fluid conduit 9500 (e.g., the first end or the second end of the fluid conduit 9500) and is configured to access a body cavity filled with a biological fluid, such as the anterior chamber of the eye, among other embodiments, as will be appreciated by those skilled in the art.

[0149] 9A-9C and 10 as including a rectangular shape, it will be understood that the eroding element 9600 may be any suitable shape without departing from the spirit or scope of the present disclosure. For example, the eroding element 9600 may be square, rectangular, trapezoidal, or other polygonal, may include chamfered or rounded edges between sides, and the sides may be essentially straight or generally curved. The eroding element 9600 may have a generally continuous curved edge in that it is circular or oval, or another suitable shape (e.g., bean-shaped). Those skilled in the art will understand that the eroding element 9600 may be any desired shape, so long as the eroding element 9600 helps protect the fluid conduit from erosion through the surrounding tissue, as described herein, and the eroding element 9600 is capable of being positioned within the subconjunctival space (such as a pocket formed between the conjunctiva and the sclera).

[0150] In some embodiments, the eroding element 9600 extends along the length of the fluid conduit but includes a length that is less than the length of the portion of the fluid conduit extending from the aqueous humor diffusion member 9002. In other embodiments, the eroding element 9600 extends along the length of the fluid conduit but includes a length that is equal to or greater than the length of the portion of the fluid conduit extending from the aqueous humor diffusion member 9002. In some embodiments, the eroding element 9600 has a width that is equal to or greater than the diameter of the fluid conduit 9500. However, in some embodiments, the width of the eroding element 9600 may be less than the diameter of the fluid conduit, so long as the eroding element 9600 is not ineffective in helping to protect the fluid conduit from erosion through the surrounding tissue. Consistent with the variety of suitable sizes and shapes of the eroding element 9600 described above, it will be understood that the width of the eroding element 9600 may remain constant along the length of the eroding element 9600, or alternatively, the width of the eroding element 9600 may vary along the length of the eroding element 9600. For example, the width can be tapered (linearly or non-linearly) along the longitudinal length of the eroding element.

[0151] In some embodiments, the erosion element 9600 can be configured to be more wear-resistant in high-wear or high-wear regions (e.g., regions where the fluid conduit 9500 may move relative to the erosion plate 9600). Wear resistance in such regions can be achieved according to any known method, including material composition and / or material thickness. Accordingly, the thickness of the erosion element 9600 can vary along the length of the erosion element 9600 and / or can vary laterally across its width. For example, the thickness can taper (linearly or non-linearly) along the length of the erosion element 9600 and / or transversely across it. For example, the thickness of the erosion element 9600 along its longitudinally extending centerline can exceed the thickness of the erosion element 9600 along one or more of its longitudinally extending edges. Alternatively, it will be understood that the thickness of the erosion element 9600 along its longitudinally extending centerline can be less than the thickness of the erosion element 9600 along one or more of its longitudinally extending edges. Additionally or alternatively, the thickness of the erosion element 9600 along a section of its longitudinal length can exceed the thickness of the erosion element 9600 along a second section of its longitudinal length. For example, a section of the erosion element 9600 closer to the end of the fluid conduit 9500 configured to access the fluid-filled body cavity may be thicker than a section of the erosion element 9600 closer to the aqueous humor diffusion member 9002, where the region where the fluid conduit 9500 accesses the fluid-filled body cavity corresponds to a high-wear region. It should be appreciated that the thickness of the erosion plate 9600 can be optimized in high-wear or high-friction regions to reduce the risk of premature failure of the glaucoma drainage system 9000 due to wear of the erosion plate 9600 by the fluid conduit 9500. These variations in thickness can be achieved by selective layering of the materials that collectively form the erosion element 9600 or other known methods.

[0152] In some embodiments, the erosion element 9600 can be longitudinally spaced from the aqueous humor diffusion member 9002 or can include a region of reduced width (e.g., as shown in FIG. 10 ) and / or thickness (not shown) extending along a region of the fluid conduit 9500 between the erosion element 9600 and the aqueous humor diffusion member 9002 that has a low risk of eroding through surrounding tissue. For example, if a portion of the fluid conduit 9500 adjacent to the aqueous humor diffusion member 9002 has a low risk of eroding the surrounding tissue, the region of reduced width and / or thickness of the erosion element 9600 can be positioned adjacent this region of the fluid conduit 9500. Alternatively, the erosion element 9600 can be configured such that the fluid conduit 9500 is exposed to the surrounding tissue in this region of low risk of erosion. Thus, in some examples, the erosion element 9600 may not extend from the aqueous humor diffusion member 9002.

[0153] In some embodiments, the erodible element 9600 is coupled to the fluid conduit 9500. The erodible element 9600 may be coupled to the fluid conduit 9500 continuously along the length of the fluid conduit 9500 or at one or more discrete locations along the fluid conduit 9500. The erodible element 9600 may be coupled to the fluid conduit 9500 according to any known method, including, but not limited to, sewing or suturing the erodible element along the length of the conduit. In some embodiments, the stitching can be a series of intermittent stitches or a continuous suturing stitch. Additionally or alternatively, the fluid conduit 9500 can be mechanically bonded to the erodible element 9600 by partially dissolving the fluid conduit 9500 into the microporous structure of the erodible element 9600. In some embodiments, the erodible element 9600 can be coated with a tacky adhesive to allow the fluid conduit 9500 to be releasably attached to the erodible element 9600. In some embodiments, one or more bands of material (e.g., microporous material) can have ends bonded to the erosion element 9600 such that an eyelet is formed between the material band and the erosion element 9600, and the fluid conduit 9500 can be threaded through the gap.

[0154] As described above, when used to treat conditions such as glaucoma, the glaucoma drainage system 9000 can be positioned within the subconjunctival space (e.g., a pocket formed between the conjunctiva and sclera of the eye). The glaucoma drainage system 9000 adopts a relatively flat, minimal radial profile within the subconjunctival space and is positioned to allow the anterior chamber of the eye to be accessed by the fluid conduit 9500. Referring now to Figures 11 and 12, the glaucoma drainage system is illustrated in an implanted configuration. Figure 11 includes a glaucoma drainage system 9000 having an aqueous humor diffusing member 9002, a fluid conduit 9500, and an erosion element 9600. Figure 12 includes a glaucoma drainage system 9000 having an aqueous humor diffusing member 9002, a fluid conduit 9500, and a plurality of first and second erosion elements 9600A and 9600B.

[0155] 11 , for example, the glaucoma drainage system 9000 is shown positioned in the subconjunctival space 2006 between the conjunctiva 2002 and the sclera 2004 of the eye 2000. The glaucoma drainage system 9000 is shown oriented such that the first layer 9010 extends along the sclera 2004 and the second layer 9020 extends along the conjunctiva 2002. It will be appreciated that the portion of the second layer 9020 that interfaces with the conjunctiva 2002 can be configured to promote or allow tissue ingrowth, as described above. It will also be appreciated that the portion of the first layer 9010 that interfaces with the sclera can additionally or alternatively be configured to promote or allow tissue ingrowth, as described above. Such a configuration helps minimize relative movement between the aqueous humor diffusion member 9002 and the surrounding tissue.

[0156] 11 as extending from the aqueous humor diffusion member 9002 and through a scleral access, perforation, or hole 2008 (e.g., created by a physician during an implantation procedure according to known methods), thereby providing access to the anterior chamber (AC) of the first end 9502. Additionally, as shown, the erosion element 9600 extends between the fluid conduit 9500 and the conjunctiva 2002 of the eye 2000. In particular, the erosion element 9600 extends between the fluid conduit 9500 and the conjunctiva 2002 such that a portion of the erosion element 9600 is positioned adjacent to or near the scleral access 2008 and / or adjacent to or near the portion 9506 of the fluid conduit extending through the scleral access 2008. Such a configuration provides that the conjunctiva 2002 is not directly exposed to the fluid conduit 9500. Instead, as shown, the erosion element 9600 extends along the conjunctiva 2002. This configuration helps protect against erosion of the fluid conduit 9500 through the conjunctiva 2002 as the erosion element 9600 acts as a protective barrier between the conjunctiva 2002 and the fluid conduit 9500. For example, the erosion element 9600 acts as a protective barrier between a fluid conduit and a portion 2010 of the conjunctiva that is positioned adjacent or close to the scleral access 2008, as shown.

[0157] It will be appreciated that the portion of the eroding element 9600 that interfaces with the conjunctiva 2002 can be configured to promote or allow tissue ingrowth, as described above. Such a configuration helps to minimize relative movement between the eroding element 9600 and the conjunctiva, even if there may be relative movement between the fluid conduit 9500 and the eroding element 9600.

[0158] Although the erosion element 9600 is shown in FIG. 11 as including a portion that extends beyond the scleral access 2008 (and thus the portion of the fluid conduit 9500 that extends through the scleral access), in some embodiments, the erosion element 9600 can extend all the way to the scleral access 2008 or less, as long as the erosion element 9600 is not ineffective in assisting in protecting against erosion.

[0159] In some embodiments, upon implantation, aqueous humor enters the first end 9502 of the fluid conduit 9500 and travels to the second end 9504 of the fluid conduit, which is in fluid communication with the aqueous humor diffusing member 9002. In some embodiments, the second end 9504 is disposed within the aqueous humor diffusing member 9002, similar to that described above with respect to the second end 1504 of the fluid conduit 1500 and the aqueous humor diffusing member 9002. Thus, as described above, the drained aqueous humor enters the reservoir defined within the aqueous humor diffusing member 9002 and permeates through the various diffusion membranes of the aqueous humor diffusing member 10002, where it can be absorbed by surrounding and / or ingrowth tissue.

[0160] Referring now to Figure 12, a glaucoma drainage system 9000 is shown positioned in the subconjunctival space 2006 between the conjunctiva 2002 and the sclera 2004 of the eye 2000. The configuration of the glaucoma drainage system 9000 shown in Figure 12 is similar to the configuration of the glaucoma drainage system 10000 shown in Figure 11, except that the glaucoma drainage system 9000 shown in Figure 12 includes two erosion elements (e.g., a first erosion element 9600A and a second erosion element 9600B). The first erosion element 9600A corresponds in structure, form, and function to the erosion element 9600 described above with respect to Figure 11. 12 includes a second erosion element 9600B in combination with a first erosion element 9600A, it will be understood that a glaucoma drainage system can include the second erosion element 9600B without the need for a first erosion element 9600A. That is, in some embodiments, the glaucoma drainage system 9000 can be configured to include an erosion element extending between the fluid conduit 9500 and the sclera 2004, without the need for an erosion element extending between the fluid conduit 9500 and the conjunctiva 2002.

[0161] 12 , the fluid conduit 9500 extends through a scleral access, perforation, or hole 2008 (e.g., created by a physician according to known methods during the implantation procedure) and through an opening 9602B in the second eroding element 9600B before extending into the anterior chamber (AC). It will be appreciated, therefore, that in various embodiments, the eroding element (e.g., the second eroding element 9600B) can include one or more incisions, perforations, or openings configured to accommodate the fluid conduit 9500. In some embodiments, the second eroding element 9600B is constructed or manufactured with such pre-formed openings. In some other embodiments, the incision, perforation, or opening can be formed in the eroding element during or immediately prior to the implantation procedure. In some embodiments, the incision, perforation, or opening is formed by a physician or physician's assistant.

[0162] As shown, the second eroding element 9600B extends between the fluid conduit 9500 and the sclera 2004, while the first eroding element 9600A extends between the fluid conduit 9500 and the conjunctiva 2002. While the second eroding element 9600B shown in FIG. 12 includes an opening 9602B and thus extends partially beyond the scleral access 2008, it will be understood that the second eroding element 9600B may not extend to or beyond the scleral access 2008 and thus may not require an opening 9602B. In such a configuration, the second eroding element 9600B may extend between the sclera 2004 and the fluid conduit 9500 to a position short of the scleral access 2008 (not shown).

[0163] A configuration including an erodible element positionable between the fluid conduit 9500 and the sclera 2004 provides that the sclera 2004 is not directly exposed to the fluid conduit 9500. Such a configuration helps protect against erosion of the fluid conduit 9500 through the sclera 2004, as such an erodible element acts as a protective barrier between the sclera 2004 and the fluid conduit 9500.

[0164] In some embodiments, the portion of the second eroding element 9600B that interfaces with the sclera 2004 can be configured to promote or allow tissue ingrowth, as described above. Such a configuration helps minimize relative movement between the second eroding element 9600B and the sclera 2004, even if there may be relative movement between the fluid conduit 9500 and the second eroding element 9600B.

[0165] In various embodiments, one or more portions of the glaucoma drainage systems discussed herein may include or be coated with one or more therapeutic agents, such as one or more glaucoma medications, as will be understood by one of ordinary skill in the art. Additionally or alternatively, in various embodiments, one or more portions of the glaucoma drainage systems discussed herein may include one or more markers (e.g., radiopaque markers) for visually or electronically determining proper placement of the glaucoma drainage system within the anatomy.

[0166] In various embodiments, the diffusion membrane material can additionally or alternatively undergo one or more processes (e.g., de-nucleation) to remove air trapped within various voids within the material. It should be understood that these processes can be combined with one or more of the hydrophilic coating processes described above. Trapped air can sometimes prevent the aqueous humor from wetting or infiltrating the material, potentially impairing the efficiency with which aqueous humor diffuses into the aqueous humor diffusing element and is reabsorbed by the body. In some embodiments, trapped air can be removed by immersing the material in a series of baths. In some embodiments, these baths can progress from one or more alcohol baths to one or more sterile water baths. [Example]

[0167] Example 1 The medical device was constructed according to the following method. A bottom sacrificial compression layer of thick expanded PTFE tape was prepared by laser cutting a small coupon of PTFE expanded tape. Specifically, the shape of the glaucoma drainage device laser cut from the sacrificial PTFE layer corresponded to the shape of the first layer 9010 shown in FIG. 10 . All chads were removed, and the sacrificial layer was aligned and placed on a jig plate configured to accommodate the small coupon. A first coupon of microporous diffusive material (e.g., multilayer ePTFE) was then placed on top of the small coupon of sacrificial PTFE material. The shape of the glaucoma drainage device was not laser cut into the first coupon of microporous diffusive material. The first coupon of microporous diffusive material was oriented so that the tissue ingrowth side of the first coupon of microporous diffusive material was facing downward toward the sacrificial PTFE coupon.

[0168] A layer of adhesive film (e.g., FEP) was then prepared by laser cutting the shape of the glaucoma drainage device into the adhesive film to the same size and location as that laser-cut on the sacrificial PTFE coupon. All chads were then removed, and the adhesive film layer was aligned and placed on top of the microporous diffusive material, ensuring that the adhesive film lay flat and free of wrinkles or folds. A second coupon of microporous diffusive material (e.g., multilayer ePTFE) was then placed on the adhesive film. The shape of the glaucoma drainage device was not laser-cut into the second coupon of microporous diffusive material. The second coupon of microporous diffusive material was oriented so that the tissue ingrowth side of the second coupon of microporous diffusive material faced up, away from the adhesive film. Next, a top sacrificial compressive layer of thickly expanded PTFE tape was placed on top of the second coupon of microporous diffusive material. The shape of the glaucoma drainage device was not laser-cut into the top sacrificial compressive layer of thickly expanded PTFE tape. In constructing this laminated stack, the jig was compressed such that the first and second coupons of microporous diffusive material were uniformly compressed except for the laser-cut areas corresponding to the size and shape of the glaucoma drainage device. That is, when the shape of the glaucoma drainage device was cut out of the first lower sacrificial layer, minimal force was applied to the areas corresponding in size and shape to the glaucoma drainage device, insufficient to form a bond between the first and second coupons of microporous diffusive material. Similarly, because the chads corresponding to the size and shape of the glaucoma drainage device were removed from the adhesive layer during the layup process, no adhesive film was applied to the corresponding areas of the first and second coupons of microporous diffusive material.

[0169] The jig and layup were then placed on a heated press platen, such as a desktop hot press preheated to about 280°C, and compressed sufficiently for a specified period of at least 5 minutes to create a bond between the first and second coupons of microporous diffusion material and the adhesive film, while avoiding significant bonding of the laminate to the sacrificial layer. The laminate was then removed from the press and allowed to cool to room temperature.

[0170] The resulting laminate was then laser cut to final size. Specifically, the cut lines followed the tracing of the glaucoma drainage device shape formed in the first sacrificial layer of PTFE, offset a short distance (approximately 1 mm) outward to include the perimeter of the device shape and portions of the first and second coupons of microporous diffusive material bonded together.

[0171] A fluid conduit formed from silicone tubing was inserted between the non-compressible layers and into the interior of the glaucoma drainage device by slightly separating the non-compressible layers and inserting the tubing up to the inner circumference defined by the first and second coupons of microporous diffusive material joined together, and the tubing was then secured to the glaucoma drainage device according to known methods.

[0172] Example 2 The medical device was constructed according to the following method. A bottom sacrificial compression layer of thick expanded PTFE tape was prepared by laser cutting a small coupon of PTFE expanded tape. A glaucoma drainage device shape consistent with the above was laser cut from the small coupon, with approximately 8 mm circular dimensions. In particular, the shape of the glaucoma drainage device laser cut from the small coupon corresponded to the shape of the second layer 9020 shown in FIG. 10. That is, the shape of the glaucoma drainage device laser cut from the small coupon included an oval-shaped aqueous humor diffusion region and a rectangular erosion element consistent with the above. All chads were removed, and the sacrificial layer was aligned and placed on a jig plate configured to accommodate the small coupon. A first coupon of microporous diffusion material (e.g., multilayer ePTFE) was then placed on top of the small coupon of sacrificial PTFE material. The shape of the glaucoma drainage device was not laser cut into the first coupon of microporous diffusion material. The first coupon of microporous diffusion material was oriented so that the tissue ingrowth side of the first coupon of microporous diffusion material faced downward toward the sacrificial PTFE coupon.

[0173] A layer of adhesive film (e.g., FEP) was then prepared by laser cutting the shape of the glaucoma drainage device, excluding the rectangular erosion element feature, into the adhesive film, identical in size and position to that laser-cut on the sacrificial PTFE coupon (but excluding the rectangular erosion element feature). Notably, the shape of the glaucoma drainage device laser-cut from the adhesive film corresponded to the shape of the first layer 9010 shown in FIG. 10 . All chads were then removed, and the adhesive film layer was aligned and placed on top of the microporous diffusive material, ensuring that the adhesive film lay flat and free of wrinkles or folds. A second coupon of microporous diffusive material (e.g., multilayer ePTFE) was then placed on the adhesive film. The shape of the rectangular erosion element was laser-cut into a second coupon of microporous diffusive material, identical in size and position to that laser-cut on the sacrificial PTFE coupon. All chads were then removed, and the second coupon of microporous diffusive material was oriented so that the tissue ingrowth side of the second coupon of microporous diffusive material faced up, away from the adhesive film.

[0174] Next, a top sacrificial compression layer of thickly expanded PTFE tape was placed on top of the second coupon of microporous diffusive material. The shape of the glaucoma drainage device was not laser cut into the top sacrificial compression layer of thickly expanded PTFE tape. In this laminated stack configuration, the jig was compressed to uniformly compress the first and second coupons of microporous diffusive material, except for the laser cut area corresponding to the size and shape of the glaucoma drainage device that was cut into the first sacrificial layer.

[0175] The jig and layup were then placed on a heated press platen, such as a desktop hot press preheated to about 280°C, and compressed sufficiently for a specified period of at least 5 minutes to create a bond between the first and second coupons of microporous diffusion material and the adhesive film, while avoiding significant bonding of the laminate to the sacrificial layer. The laminate was then removed from the press and allowed to cool to room temperature.

[0176] The resulting laminate was then laser cut to a final size consistent with the laser cutting process of Example 1, except that no offset was cut around the rectangular portion defining the erodible element. The resulting laminate included a bottom microporous diffusive material layer that matched the size and shape of the second layer 9020 shown in Figure 10 and a top microporous diffusive material layer that matched the size and shape of the first layer 9010 shown in Figure 10.

[0177] A fluid conduit formed from silicone tubing was inserted between the non-compressible layers and into the interior of the glaucoma drainage device by slightly separating the non-compressible layers and inserting the tubing up to the inner circumference defined by the first and second coupons of microporous diffusive material joined together, and the tubing was then secured to the glaucoma drainage device according to known methods.

[0178] Example 3 The hydrophobic ePTFE device assemblies from Examples 1 or 2 were hydrophilically coated as follows: The ePTFE was wetted by delivering approximately 1 ml of 100% isopropyl alcohol directly through the fluid conduit (e.g., silicone tubing) of the device and flushed through the ePTFE reservoir. Approximately 1 ml of deionized water (nominal resistance, approximately 10 psi) was then pumped through the fluid conduit and ePTFE reservoir. 6 Excess alcohol was flushed from the device using a 1000 ohm (1000 psi) pressure. Next, approximately 1 ml of a 0.2 wt% aqueous polyvinyl alcohol solution was flushed directly through the fluid conduits and ePTFE reservoir and allowed to equilibrate for approximately 10 minutes. Approximately 1 ml of distilled water was flushed through the fluid conduits and ePTFE reservoir. Approximately 1 ml of a crosslinking aqueous solution (2 vol% glutaraldehyde in approximately 0.3 molar hydrochloric acid) was heated to approximately 40°C and flushed directly through the device and allowed to equilibrate for approximately 15 minutes. Approximately 2.5 ml of deionized water was flushed through the fluid conduits and ePTFE reservoir. The material was then equilibrated in a beaker of approximately 40 ml of fresh deionized water.

[0179] The resulting assembly was then dried in an air oven at 115°C for approximately 10 minutes.

[0180] Example 4 The device from Example 3 was implanted in the superotemporal quadrant of New Zealand White rabbits at the subconjunctival plane and evaluated for survival over 14 days. During implantation, a tunnel was created at the limbus using a 25-gauge needle, where a fluid conduit was routed into the anterior chamber. A 0.01% aqueous solution of fluorescein was used to visualize the aqueous humor reservoir. The injected fluorescein is excited by ultraviolet light, emitting strong fluorescence and easily visible in a darkened environment. Prior to sacrifice, a 0.01% aqueous solution of fluorescein was infused into the anterior chamber of the implanted eye through a 30-gauge needle at a nominal flow rate of approximately 10 μL / min for approximately 10 minutes. At 14 days, a strongly fluorescent reservoir was observed, along with fluorescent conduits emanating from the implanted reservoir area.

[0181] The scope of the invention of this application has been described above generally and with reference to specific examples. It will be apparent to those skilled in the art that various modifications and variations can be made in the examples without departing from the scope of the present disclosure. Similarly, various components discussed in the examples discussed herein can be combined. Therefore, the examples are intended to cover modifications and variations within the scope of the present invention. (Aspect) (Aspect 1) a body including a first microporous membrane, a second microporous membrane, a third microporous membrane, and a fourth microporous membrane in a stacked configuration, the second and third microporous membranes being disposed between the first and fourth microporous membranes, and an expandable reservoir being defined between the second and third microporous membranes, wherein 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; a fluid conduit having a first end and a second end, the first end fluidly coupled to the reservoir and the second end extending exteriorly of the body and insertable into a fluid-filled body cavity such that fluid from the fluid-filled body cavity can be transferred to the reservoir; A biological fluid drainage device comprising: (Aspect 2) 2. The device of embodiment 1, wherein the second and third microporous membranes are partially bonded to one another such that portions of the second and third microporous membranes are free to slide relative to one another or separate from one another. (Aspect 3) 3. The device of any one of embodiments 1 or 2, wherein the second and third microporous membranes each have a permeability different from the permeability of each of the first and fourth microporous membranes. (Aspect 4) The device of any one of embodiments 1 to 3, wherein at least one of the first, second, third, and fourth microporous membranes comprises expanded polytetrafluoroethylene. (Aspect 5) 5. The device of any one of aspects 1 to 4, further comprising a fifth microporous membrane disposed adjacent to the body, the fifth microporous membrane extending between the body and the second end of the fluid conduit. (Aspect 6) The device of embodiment 5, wherein the fifth microporous membrane is configured to permit tissue ingrowth. (Aspect 7) The device of any one of embodiments 5-6, wherein the fifth microporous membrane is attached to the fluid conduit. (Aspect 8) The device of any one of aspects 5 to 7, wherein the fifth microporous membrane is integral with one of the first, second, third, or fourth microporous membranes. (Aspect 9) The device of embodiment 8, wherein the fifth microporous membrane and the first microporous membrane are the same microporous membrane. (Aspect 10) 10. The device of any one of aspects 5-9, further comprising a sixth microporous membrane disposed adjacent to the body, the sixth microporous membrane extending between the body and the second end of the fluid conduit. (Aspect 11) 11. The device of embodiment 10, wherein the sixth microporous membrane and the fourth microporous membrane are the same microporous membrane. (Aspect 12) 12. The device of any one of aspects 10-11, wherein the sixth microporous membrane includes perforations sized to accommodate a fluid conduit such that, upon implantation, the fluid conduit can be extended through the perforations into a fluid-filled body cavity. (Aspect 13) 13. The device of any one of aspects 1-12, wherein the first and fourth microporous membranes are configured to remain permeable to the fluid after tissue ingrowth occurs in the first and fourth microporous membranes, respectively. (Aspect 14) 14. The device of any one of embodiments 1-13, wherein the reservoir is configured to expand when the fluid is transferred to the reservoir. (Aspect 15) 15. The device of embodiment 14, wherein the body is configured to adopt a predetermined profile as a result of expansion of the reservoir. (Aspect 16) 16. The device of any one of aspects 1 to 15, wherein the first, second, third, and fourth microporous membranes each comprise a plurality of pores, wherein the plurality of pores in the second and third microporous membranes are sized to resist tissue ingrowth and the plurality of pores in the first and fourth microporous membranes are sized to permit tissue ingrowth. (Aspect 17) a first proliferative diffusion membrane configured to permit tissue ingrowth; a first constricting diffusion membrane configured to resist tissue ingrowth, the first constricting diffusion membrane coupled to the first proliferative diffusion membrane; a second constricting diffusion membrane configured to resist tissue ingrowth, the second constricting diffusion membrane being bonded to the first constricting diffusion membrane such that a first region of the second constricting diffusion membrane is bonded to the first constricting diffusion membrane and a second region of the second constricting diffusion membrane is unbonded from the first constricting diffusion membrane, the unbonded second region defining an expandable reservoir; a second proliferative diffusion membrane configured to permit tissue ingrowth, the second proliferative diffusion membrane being coupled to the second constrictive diffusion membrane; An aqueous humor diffusing device comprising: (Aspect 18) 20. The device of embodiment 17, wherein the first and second proliferative diffusion membranes comprise a plurality of pores configured to permit tissue ingrowth, and the first and second constrictive diffusion membranes comprise a plurality of pores configured to resist tissue ingrowth. (Aspect 19) 19. The device of any one of embodiments 17 to 18, wherein the first region of the second constricting diffusion membrane is a peripheral region of the second constricting diffusion membrane, the first region of the second constricting diffusion membrane is bonded to the peripheral region of the first constricting diffusion membrane, and the second region of the second constricting diffusion membrane is a region inside the peripheral region of the second constricting diffusion membrane. (Aspect 20) 20. The device of any one of aspects 17-19, further comprising a fluid conduit having a first end and a second end, the first end being fluidly connected to the reservoir and the second end extending away from the first and second constricting diffusion membranes, the device being insertable into a fluid-filled body cavity such that fluid from the fluid-filled body cavity can move into the reservoir. (Aspect 21) 21. The device of embodiment 20, further comprising a third proliferative diffusion membrane comprising a plurality of pores sized to allow tissue ingrowth, the third proliferative diffusion membrane positioned adjacent to the first proliferative diffusion membrane and extending along the fluid conduit between the first proliferative diffusion membrane and the second end of the fluid conduit. (Aspect 22) 22. The device of embodiment 21, wherein the third proliferative membrane and the first proliferative diffusion membrane are the same proliferative diffusion membrane. (Aspect 23) 23. The device of any one of embodiments 21-22, wherein the third proliferative diffusion membrane is coupled to the fluid conduit. (Aspect 24) 24. The device of any one of aspects 20-23, further comprising a fourth proliferative diffusion membrane comprising a plurality of pores sized to permit tissue ingrowth, the fourth proliferative diffusion membrane positioned adjacent to the second proliferative diffusion membrane and extending along the fluid conduit between the second proliferative diffusion membrane and the second end of the fluid conduit. (Aspect 25) 25. The device of embodiment 24, wherein the fourth proliferative membrane and the second proliferative diffusion membrane are the same proliferative membrane. (Aspect 26) 26. The device of any one of embodiments 24-25, wherein the fourth proliferative diffusion membrane comprises perforations sized to accommodate a fluid conduit such that, upon implantation, the fluid conduit extends through the perforations into a fluid-filled body cavity. (Aspect 27) 27. The device of any one of embodiments 1 to 26, wherein the fluid-filled body cavity is the anterior chamber of the eye and the fluid is aqueous humor. (Aspect 28) providing a first proliferative diffusion membrane and a second proliferative diffusion membrane; providing a first constricting diffusion membrane and a second constricting diffusion membrane; bonding the first proliferative diffusion membrane to the first constrictive diffusion membrane; bonding the first constrictive diffusion membrane to the second constrictive diffusion membrane such that a first region of a first interface surface of the second constrictive diffusion membrane is bonded to the first constrictive diffusion membrane and a second region of the first interface surface is not bonded to the first constrictive diffusion membrane; and bonding the second proliferative diffusion membrane to the second constrictive diffusion membrane, thereby forming an aqueous humor diffusing element; coupling the fluid conduit to the aqueous humor diffusing member such that the fluid conduit is fluidly coupled with the reservoir such that the conduit is operable to deliver drained aqueous humor to the reservoir; Including, wherein the first and second proliferative diffusion membranes are each configured to permit tissue ingrowth; the first and second constrictive diffusion membranes are configured to resist tissue ingrowth; the unbonded second region defines an expandable reservoir; A method for forming a glaucoma drainage device. (Aspect 29) The method of embodiment 28, wherein the aqueous humor diffusion member further comprises a third proliferative diffusion membrane configured to allow tissue ingrowth, the third proliferative membrane positioned adjacent to the first proliferative diffusion membrane and extending along the fluid conduit. (Aspect 30) 30. The method of embodiment 29, wherein the aqueous humor diffusion member further comprises a fourth proliferative diffusion membrane configured to allow tissue ingrowth, the fourth proliferative membrane positioned adjacent to the second proliferative diffusion membrane and extending along the fluid conduit. (Aspect 31)

[0039] Aspect 31. The method of any one of aspects 28-30, further comprising perforating one of the first, second, third, or fourth proliferative diffusion membranes to comprise a plurality of pores sized to permit tissue ingrowth. (Aspect 32) Aspect 3, wherein the third proliferative diffusion membrane and the first proliferative diffusion membrane are the same proliferative diffusion membrane. 32. The method according to any one of items 0 to 31. (Aspect 33) The method according to any one of aspects 30 to 32, wherein the fourth proliferative diffusion membrane and the second proliferative diffusion membrane are the same proliferative diffusion membrane. (Aspect 34)

[0039] Aspect 34. The method of any one of aspects 30-33, wherein the fourth proliferative diffusion membrane comprises perforations sized to accommodate the fluid conduits such that, upon implantation, the fluid conduits can extend through the perforations into the anterior chamber.

Claims

1. 1. An implantable biological fluid drainage device for draining fluid from a fluid-filled body cavity, comprising: a body defining a first layer, a second layer coupled to at least a portion of the first layer, an expandable reservoir between the first layer and the second layer, and one or more erodible elements extending away from the body and configured to minimize erosion of a fluid conduit through one or more tissues of an eye when the implantable biological fluid drainage device is implanted; a fluid conduit having a first end and a second end, the first end fluidly coupled to the expandable reservoir and the second end extending outside the body and insertable into a fluid-filled body cavity such that the fluid from the fluid-filled body cavity can be transferred to the expandable reservoir; 1. An implantable biological fluid drainage device comprising:

2. 2. The implantable biological fluid drainage device of claim 1, wherein the first layer comprises a first proliferative diffusion membrane and a first constrictive diffusion membrane, and the second layer comprises a second proliferative diffusion membrane and a second constrictive diffusion membrane.

3. 2. The implantable biological fluid drainage device of claim 1, wherein the implantable biological fluid drainage device is implantable within a pocket formed between the conjunctiva and sclera of the eye, whereby the body is positioned within the pocket and the fluid conduit penetrates the sclera to access the anterior chamber of the eye.

4. An implantable biological fluid drainage device according to any one of claims 1 to 3, wherein when the implantable biological fluid drainage device is implanted in the eye, a first erodible element of the one or more erodible elements covers the fluid conduit to form a barrier between the fluid conduit and the conjunctiva.

5. An implantable biological fluid drainage device as described in any one of claims 1 to 3, wherein the one or more erosion elements are coupled to at least one portion of the implantable biological fluid drainage device such that the one or more erosion elements are detachable from the implantable biological fluid drainage device.

6. An implantable biological fluid drainage device as described in any one of claims 1 to 3, wherein a portion of the fluid conduit extends from the body to an extended length, and the one or more erodible elements extend along the length of the fluid conduit a distance shorter than the extended length.

7. The implantable biological fluid drainage device of any one of claims 1 to 3, wherein the one or more erodible elements have a width equal to or greater than a diameter of the fluid conduit.

8. The implantable biological fluid drainage device of any one of claims 1 to 3, wherein the width of the one or more erodible elements remains constant in a direction along the length of the one or more erodible elements.

9. An implantable biological fluid drainage device as described in any one of claims 1 to 3, wherein the one or more erosion elements are configured to resist abrasion of the surrounding tissue of the implantable biological fluid drainage device in high wear areas where the fluid conduit may move relative to the one or more erosion elements.

10. An implantable biological fluid drainage device as described in any one of claims 1 to 3, wherein the thickness of the one or more erodible elements tapers linearly or non-linearly along at least one length of the one or more erodible elements and laterally across the one or more erodible elements.

11. The implantable biological fluid drainage device of any one of claims 1 to 3, wherein the one or more erodible elements are longitudinally spaced from the body.

12. An implantable biological fluid drainage device according to any one of claims 2 to 3, wherein the one or more erosion elements extend between the fluid conduit and the conjunctiva, and a portion of the one or more erosion elements that interfaces with the conjunctiva is configured to promote tissue ingrowth so as to minimize relative movement between the one or more erosion elements and the conjunctiva.

13. 13. The implantable biological fluid drainage device of claim 12, wherein the one or more erosion elements are positioned such that a portion of the one or more erosion elements is positioned adjacent to or near a scleral access and / or a portion of the fluid conduit extending through the scleral access.

14. 2. The implantable biological fluid drainage device of claim 1, wherein the one or more erosion elements include a second erosion element extending along a portion of the fluid conduit so as to form a barrier between the fluid conduit and the sclera of the eye when the biological fluid drainage device is implanted in the eye.

15. At least one laminate or bonding layer including a proliferative diffusion membrane disposed on a first side and a constrictive diffusion membrane disposed on a second side; one or more erosion elements; a body having 1. An implantable biological fluid drainage device for draining fluid from a fluid-filled body cavity, comprising: the at least one laminate or bonding layer being arranged to form an expandable reservoir for receiving the fluid from the fluid-filled body cavity; The at least one laminate or tie layer comprises: promoting tissue ingrowth on the first side of the laminate or tie layer; preventing tissue ingrowth on the second side of the laminate or tie layer; and permeating biological fluid of the fluid-filled body cavity through the fluid-filled body cavity; It is structured as follows: the first side of the laminate or bonding layer is an outermost layer of the body so that the implantable biological fluid drainage device can be attached to surrounding tissue after implantation; the second side of the laminate or tie layer being an innermost layer of the body such that tissue ingrowth into the expandable reservoir is prevented; An implantable biological fluid drainage device, wherein the one or more erosion elements extend away from the body and are configured to minimize erosion of a fluid conduit through one or more tissues of the eye when the implantable biological fluid drainage device is implanted.

16. 16. The implantable biological fluid drainage device of claim 15, wherein the first side of the laminate or bonding layer has a first microstructure and the second side of the laminate or bonding layer has a second microstructure that is different from the first microstructure.

17. 16. The implantable biological fluid drainage device of claim 15, wherein the implantable biological fluid drainage device is implantable within a pocket formed between the conjunctiva and the sclera of the eye so that the one or more erosive elements extend along and therebetween, and the portion of the one or more erosive elements that interface with the conjunctiva is configured to promote tissue ingrowth so as to minimize relative movement between the one or more erosive elements and the conjunctiva.

18. 18. An implantable biological fluid drainage device as described in any one of claims 15 to 17, further comprising a fluid conduit having a first end and a second end, the first end fluidly connected to the expandable reservoir and the second end extending outside the body and insertable into the fluid-filled body cavity so that the fluid from the fluid-filled body cavity can move into the reservoir, and a first erosion element of the one or more erosion elements covers the fluid conduit.

19. 20. The implantable biological fluid drainage device of claim 18, wherein the one or more erodible elements are positioned to form a barrier between the fluid conduit and the conjunctiva when the implantable biological fluid drainage device is implanted in the eye.

20. 1. A method of forming an implantable biological fluid drainage device for draining fluid from a fluid-filled body cavity, comprising: selecting at least one laminate or tie layer comprising a proliferative diffusion membrane disposed on a first side and a constrictive diffusion membrane disposed on a second side; promoting tissue ingrowth on the first side of the laminate or tie layer; preventing tissue ingrowth on the second side of the laminate or tie layer; and permeating biological fluid of the fluid-filled body cavity through the fluid-filled body cavity; selecting at least one laminate or bonding layer configured to: an expandable reservoir on a second side of the laminate or tie layer; one or more erosion elements; disposing said at least one laminate or bonding layer to form a body defining a Including, the expandable reservoir is configured to receive the fluid from the fluid-filled body cavity; the one or more erodible elements extend in a direction away from one of the at least one laminate or bonding layer and are configured to minimize erosion of a fluid conduit through one or more tissues of the eye when the implantable biological fluid drainage device is implanted; The method, wherein the first side of the laminate or bonding layer is configured to attach to surrounding tissue after implantation, and the second side of the laminate or bonding layer is configured to prevent tissue ingrowth into the expandable reservoir.

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