Aspects of the present disclosure are generally directed to systems and methods employing implantable devices that drain aqueous humor from an anterior chamber of an eye to a location external to or distal from the anterior chamber and, more particularly, to systems and methods that prevent and/or remove the accumulation of obstructive material in such implantable devices.
Glaucoma is a group of chronic optic nerve diseases and a leading cause of irreversible blindness. The major risk factor in glaucoma is elevated intraocular pressure due to improper drainage of aqueous humor from the eye. Reduction of intraocular pressure is the only proven treatment to stop the progression of vision loss due to glaucoma.
Standard glaucoma surgeries to reduce intraocular pressure, such as trabeculectomies and glaucoma drainage device implantation, tend to be lengthy and traumatic with unpredictable outcomes and complication rates of 20-60%. Implantable drainage devices operate to drain excess aqueous humor from the eye, and installation of such drainage devices typically requires a surgical opening to be made in the sclera to reach the interior of the eye, in particular the anterior chamber or the posterior chamber.
Dry eye disease is a common and complex condition in which the tear film layer is not properly maintained. Symptoms can range from intermittent and mild to a chronic, vision-threatening state. Tear production is similar to aqueous humor production and has a similar chemical composition.
Treatments for dry eye include topical drops, puncta occlusion, and gland stimulation treatments. Topical drops provide temporary relief and require frequent dosing. Punctal occlusion via plugs or cautery may be used to stop the uptake of tears by the puncta. However, punctal occlusion has poor retention rates and cautery is irreversible. Gland stimulation may also be used to increase tear break up time, but it is not effective in all patients and is a short-term solution. Therefore, there is an ongoing need to provide a therapy that provides continuous relief.
According to aspects of the present disclosure, systems and methods employ implantable devices that drain aqueous humor from an anterior chamber of an eye to a location external or distal to the anterior chamber. According to further aspects, the systems and methods prevent and/or remove the accumulation of obstructive material in such implantable devices. Such systems and methods may be employed to reduce intraocular pressure in order to treat glaucoma. Additionally or alternatively, such systems and methods may be employed to treat dry eye by directing the aqueous humor to the ocular surface where it can act as a lubricant.
According to one embodiment, a device for draining aqueous humor from an eye includes an inlet conduit configured to be positioned at least partially within an anterior chamber of an eye. The device includes a housing coupled to the inlet conduit. The housing defines a cavity that is in fluid communication with the inlet conduit. The inlet conduit includes an inlet passageway allowing aqueous humor to flow from the anterior chamber to the cavity. The device includes an outlet conduit extending from a proximal end to a distal end. The outlet conduit is coupled to the housing at the proximal end and in fluid communication with the cavity of the housing. The outlet conduit includes an outlet passageway allowing the aqueous humor to flow from the cavity at the proximal end to an external ocular surface via an outlet opening at the distal end. The device includes an anti-clogging element coupled to the outlet conduit and configured to prevent or remove an obstruction of the outlet conduit at the distal end caused by material from the external ocular surface.
According to another embodiment, a device for draining aqueous humor from an eye includes an inlet conduit configured to be positioned at least partially within an anterior chamber of an eye. The device includes a housing coupled to the inlet conduit. The housing includes a cavity that is in fluid communication with the inlet conduit. The inlet conduit includes an inlet passageway allowing aqueous humor to flow from the anterior chamber to the cavity. The device includes an outlet conduit extending from a proximal end to a distal end. The outlet conduit is coupled to the housing at the proximal end and in fluid communication with the cavity of the housing. The outlet conduit includes an outlet passageway allowing the aqueous humor to flow from the cavity at the proximal end to an external ocular surface via an outlet opening at the distal end. The outlet conduit is formed at least partially from a material having anti-fouling properties.
These and other aspects of the present disclosure will become more apparent from the following detailed description of embodiments of the present disclosure when viewed in conjunction with the accompanying drawings, which are briefly described below.
The present disclosure now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all aspects of the disclosure are shown. Indeed, the disclosure may be embodied in many different forms and should not be construed as limited to the aspects set forth herein.
Implantable drainage devices operate to drain excess aqueous humor from the eye, and installation of such drainage devices typically requires a surgical opening made in the sclera to reach the interior of the eye, in particular the anterior chamber or the posterior chamber. Some drainage devices, also known as subconjunctival shunts, can be inserted into the interior of the eye to conduct the aqueous humor to the subconjunctival space. A problem associated with subconjunctival shunts, however, involves potential scarring of the bleb in the subconjunctival space and fibrous capsule formation around the outlet, which in many cases requires surgical revision that leads to additional risk of complications.
Other drainage devices, also known as external shunts, drain aqueous humor from the interior of the eye externally to the conjunctiva. External shunts avoid bleb and fibrous capsule formation and the unpredictability of wound healing in the subconjunctival space. Often, however, parts of an external shunt especially those that lie on the corneal surface, may he perceived by the patient to be a foreign body. External shunts can also be displaced by local tissue motion or extruded by constrictive wound healing processes. Furthermore, conduits of external shunts can transmit microorganisms from the outside to the interior of the eye, potentially leading to retrograde infection.
Embodiments according to the present disclosure address the disadvantages of current drainage devices and provide an improved drainage device for directing aqueous humor away from the anterior chamber to a desired location external to or distal from the anterior chamber. The drainage device may be employed to treat glaucoma by reducing intraocular pressure. Additionally or alternatively, the drainage device may be employed to treat dry eye disease by directing the aqueous humor to lubricate the ocular surface.
To provide improved features for the drainage device 100a, tissue integration agents 112 may be applied to the housing 104a and/or the outlet conduit 106a, The tissue integration agents 112 can help position the housing 104a and/or the outlet conduit 106a more securely against surfaces/features of the eye when the drainage device 100a is implanted. Additionally or alternatively, other types of agents 114 may be applied to the inlet conduit 102, the housing 104a, and/or the outlet conduit 106a. Such agents 114, for instance, may include antimicrobial and/or medicinal agents.
As also shown in
Creating a flow path from the anterior chamber to the external ocular surface with the drainage device 100a might raise concerns over the migration of microorganisms, such as bacteria, viruses, fungi, and spores, into the anterior chamber 12 and the corresponding risk of infection and inflammation. The filtration system 108a operates to prevent the upstream migration of microorganisms into the inlet conduit 102 and the anterior chamber 12, thereby reducing the likelihood of infection. Antimicrobial agents or materials may also be employed in the filtration system 108a. For instance, an antimicrobial coating may applied to aspects of the filtration system 108a or aspects of the filtration system 108a may be formed from materials including antimicrobial agents.
In some cases, the filtration system 108a includes a material with pores that are sufficiently small, e.g., less than approximately 0.4 μm, to prevent migration of microorganisms. For instance, the porous material may be a microporous/nanoporous membrane or polymer network, fiber network, or microcapsular material having a network of pores. In further cases, the pores may be arranged according to a gradient of pore sizes along the length of the filtration system 108a. For instance, the pores may be arranged so that the pore sizes continually decrease in the direction of flow from the inlet conduit 102 toward the outlet conduit 106a. The gradient of pore sizes can prevent debris accumulation and clogging within the filtration system 108a.
The control device 110a can provide resistance to achieve a particular rate for the flow of the aqueous humor 14 through the cavity of the housing 104a. The control device 110a may be removable and/or adjustable to achieve the particular flow rate and pressure gradient. In some cases, the filtration system 108a can also provide resistance to the flow of the aqueous humor 14.
As also shown in
The drainage device 200 includes a filtration system 208, which is disposed in the cavity of the housing 204. As described above, the filtration system 208 operates to prevent migration of microorganisms into the inlet conduit 202 and reduce the likelihood of reflux infection. The drainage device 200 also includes an outlet conduit 206. The housing 204 is coupled to a proximal end of the outlet conduit 206. As shown in
The drainage device 200 also includes a control device 210, which is disposed in the outlet conduit 206. The control device 210 is configured to regulate the intraocular pressure within the drainage device 200. In particular, the control device 210 can provide resistance to achieve a particular rate for the flow of the aqueous humor through the outlet conduit 206. The control device 210 may be removable and/or adjustable to achieve the particular flow rate.
All drainage devices implanted in the eye have the potential to clog from proteins or other substances in the aqueous humor. Clogging reduces flow through a drainage device and may lead to elevation of intraocular pressure compared to baseline. Obstructive material may include endogenous material produced inside the eye or on the ocular surface, such as proteins and cells, and exogenous material, such as allergens, debris, or pathogens, that can foul one or more aspects of a drainage device. Specific embodiments disclosed herein prevent and/or remove the accumulation of obstructive material in such implantable devices. As described herein, preventing the accumulation of obstructive material can mean reducing, completely or by any other amount, the likelihood of any such accumulation.
In particular, the present inventors have identified an unanticipated problem involving the encapsulation of mucosubstances at the outlet conduit of the drainage devices described above. The encapsulation of mucosubstances results in the obstruction of the outlet conduit. Therefore, in some embodiments, anti-clogging elements are employed to prevent and/or remove the occurrence of such an obstruction of the outlet conduit.
According to an embodiment, the outlet conduit 406 is coupled, at the proximal end 406c, to a housing of the drainage device. The housing device is also coupled to an inlet conduit which can be positioned at least partially within an anterior chamber of an eye. The housing includes a cavity that is in fluid communication with the inlet conduit. The inlet conduit includes an inlet passageway that allows aqueous humor to flow from the anterior chamber to the cavity of the housing. Meanwhile, the outlet passageway 406b of the outlet conduit 406 is in fluid communication with the cavity of the housing and allows the aqueous humor to flow from the cavity to the external ocular surface.
As shown further in
The wicking material 422 may be formed from biocompatible permeable or porous materials, including for instance polyhydroxyethylmethacrylate, polyurethane, polystyrene-co-isobutylene-co-styrene, polyethylene, polyacrylamide, polyvinyl alcohol, silicone, polycarbonate, polyethersulfone, polytetrafluoroethylene, or the like. In some cases, the wicking material 422 can be inserted into the outlet conduit 406 and can susbequently expand into a tight mechanical fit (e.g., seal) against the interior surface of the outlet conduit 406. For instance, the wicking material 422 can absorb water and expand into a tight mechanical fit. Alternatively, the wicking material 422 can be compressible so that it can be squeezed into the outlet conduit 406 and form a tight mechanical fit.
When an obstruction results from the clogging material captured by the wicking material 416, the wicking material 416 can be removed from the outlet conduit 406. As such, the obstruction caused by the clogging material can be easily removed while the drainage device remains implanted. The removed wicking material 416 can be replaced with a new wicking material to prevent additional material from flowing through the outlet conduit 406.
As
As shown further in
When an obstruction results from material collected on the porous covering 522, the porous covering 522 can be removed from the outlet conduit 506. The obstruction caused by the material can be easily removed while the drainage device remains implanted. The removed porous covering 522 can be replaced with a new porous covering to prevent additional clogging material from flowing through the outlet conduit 506.
The porous covering 522 may be formed from an expandable material. As such, the porous covering 522 can be stretched to allow the porous covering 522 to slide onto or off the outlet conduit 506 more easily. Additionally, the expandable material also allows the porous covering 522 to engage the exterior surface of the outlet conduit 506 so that the porous covering 522 can remain securely over the outlet conduit 506 until intentional removal. The porous covering 522 may also be formed from softer materials that result in less irritation of ocular surfaces. Such materials, for instance, may include poly(2-hydroxyethyl methacrylate), poly vinyl alcohol, polyurethane, styrene isobutylene, or the like.
As shown further in
In addition, due to the position of the inner conduit 622 at the distal end 606d, any clogging material from the external ocular surface is collected in the inner-conduit passageway 622b. When an obstruction results from collected material, the inner conduit 622 can be removed from the outlet conduit 606. The obstruction caused by the material can be easily removed while the drainage device remains implanted. The removed inner conduit 622 can be replaced with a new inner conduit for further use of the drainage device.
The inner conduit 622 fits securely against the wall 606a of the outlet conduit 606 and remains in position when experiencing typical physiologic forces associated with use of the drainage device but can be manually removed from the outlet conduit 606 when required. The outlet passageway 606b may be shaped to accommodate the inner conduit 622. For instance, as illustrated in
As described above, the anti-clogging elements 420, 520, 620 allow obstructions to be removed from a drainage device while the drainage device remains implanted. Aspects of the outlet conduits 406, 506, 606 and/or the anti-clogging elements 420, 520, 620 may be additionally formed from, or treated with, materials that resist fouling to reduce the likelihood of obstructions. The materials, for instance, may be resistant to fouling caused by bacteria and other microorganisms. Additionally, the materials may have low binding affinity to mucosubstances.
Encapsulation of mucosubstances can result in the obstruction of the outlet conduit 406, 506, 606. The production of mucosubstances is associated with an immune response to foreign material on a mucous membrane. Because mucosubstances are attracted to microbes, the use of antimicrobial materials can reduce the likelihood of fouling due to the production of mucosubstances.
In general, the use of antimicrobial agents, as well as anti-scarring, fibrinolytic, anti-coagulant, and anti-inflammatory agents, in the materials can reduce the likelihood of contamination and obstruction. In some embodiments, aspects of the drainage devices may employ materials that are impregnated, coated, or absorbed with anti-fouling agents. Such materials may include: RNA III inhibiting peptide (inhibits cell-cell communication, leading to prevention of their adhesion and virulence); ionized fluoroplastic coatings (resistant to bacterial adhesion); selenium, gold, and/or silver (prevents the normal buildup of bacteria, film, and deposits on lenses); polyethylene glycol (provides physical, chemical, and biological barriers to the nonspecific binding of proteins, bacteria, and fibroblast cells); polyelectrolyte (promotes protein and cell immobilization); and/or heparin,
In further embodiments, aspects of the drainage devices may employ anti-fouling materials including polyisobutylene-co-polyurethane or polystyrene-co-isobutylene-co-styrene. In other embodiments, aspects of the drainage devices may include anti-fouling materials that are block copolymers which develop a micro-morphology with soft segment and hard segment domains, where the micro-morphology may be preferably measured in domains of 100 nanometers or less. In yet other embodiments, aspects of the drainage devices may employ materials that are etched or textured to resist attachment by microorganisms and mucosubstances.
As described above, agents may be employed to promote tissue integration of a drainage device. In some embodiments, a porous material may be additionally or alternatively employed on appropriate aspects of a drainage device to enhance tissue integration in subconjunctival regions. Such tissue integration can also reduce production of mucosubstances.
As described above, the outlet conduit of a drainage device may include a proximal portion coupled to the housing and a distal portion including an outlet opening through which the aqueous humor exits to the external ocular surface. In alternative embodiments, the distal portion may be coupled to the proximal portion by a connector that is operable to allow removal and replacement of the distal portion. Such embodiments provide another approach for removing an obstruction in the distal portion of the outlet conduit. In some cases, the proximal portion is configured to extend from the housing to a conjunctival location where the distal portion can be accessed and removed.
Embodiments above are configured to address obstructions in the outlet conduit caused by clogging materials from the external ocular surface. According to other aspects of the present disclosure, drainage devices may include anti-clogging elements that can prevent obstructions in other parts of the drainage devices. For instance, embodiments that employ filtration systems risk obstruction over time, so anti-clogging elements may be employed to prevent or remove the occurrence of obstructions within the filtration systems.
As also shown in
To slow the formation of any obstruction at the filter 708, the drainage device 700 also includes a trap 730 configured to keep proteins in the aqueous humor from flowing to the filter 708. As shown in
The screen 832 can collect the proteins in the flow before they reach the filter 808. The second porous material may include pores that are larger than pores of the first porous material of the filter 808, for instance, between approximately 0.4 μm to approximately 1000 μm.
Agents (e.g., anti-scarring, fibrinolytic, anti-coagulant, and anti-inflammatory agents) may be applied to the screen 832 to enhance anti-clogging characteristics. Some agents include those that combat fibroblast proliferation, which is involved in wound healing and contributes to scar formations (fibrosis). For instance, 5-fluorouracil is an agent that inhibits fibroblast proliferation. Other agents include mitomycin C. Yet other agents include collagenases which are enzymes that catalyze the hydrolysis of collagen and gelatin to prevent scarring. Another agent is heparin which has been used to coat intraocular lenses (IOLs) to reduce membrane formation. Heparin-sodium has been shown to reduce inflammation. Further agents include steroids such as triamcinolone or one of four essentially equivalent maximum-efficacy steroids: loteprednol etabonate 0.5%, 1% prednisolone acetate (Pred Forte), 1% prednisolone sodium phosphate, or 1% rimexolone for moderate to severe inflammation; and fluorometholones for mild to moderate inflammation.
In addition to reducing the likelihood of obstruction at the filter 808, the trap 830 may be further configured to change the fluid velocity profile of the flow of aqueous humor as it meets the filter 808. For instance, the screen 832 can modify the flow to have a more uniform velocity across the filter 808.
Once the filters 708, 808 become obstructed, the filters 708, 808 (or the drainage devices 700, 800 entirely) need replacement. Thus, by employing the traps 730, 830 to prevent obstruction at the filters 708, 808, the useful life of the filters 708, 808 can be prolonged.
According to another approach, drainages devices may be configured to allow clogging proteins to be flushed from the filter and/or the inlet conduit. For instance,
To remove the clogging proteins from the filter 908, a flushing fluid can be delivered into the drainage device 900. The outlet conduit 906 includes an opening 906a where the aqueous humor flows out of the drainage device 900 to the external ocular surface. The opening 906a can also act as a two-way port to receive the flushing fluid. The flushing fluid flows through the outlet conduit 906 in a direction opposite to the flow of the aqueous humor. Thus, the flushing fluid flows into the cavity 904a and through the filter 908. As the flushing fluid flows through the filter 908, the flushing fluid can dislodge proteins that are clogging the filter 908. The flushing fluid then flows into the inlet conduit 902, carrying the dislodged protein from the filter 908.
As shown in
To allow the flushing fluid to dislodge the proteins more effectively, the filter 908 may be oriented to maximize the velocity of the flushing fluid at the filter 908. For instance, as shown in
Rather than employing the outlet opening 906a as a two-way port, alternative embodiments may employ the outlet opening 906a only to allow the aqueous humor to flow from the outlet conduit 906 and a separate flushing opening that receives the flushing fluid into the drainage device. In such embodiments, the first opening and the second opening each act as one-way ports.
Rather than allowing the flushing fluid to flow through the inlet conduit 902 to the anterior chamber, alternative embodiments may include a secondary flushing opening that allows the flushing fluid to flow out of the drainage device 900 into external region(s) or tissue(s) other than the anterior chamber. In some cases, a valve can control flow out of this secondary flushing opening. For instance, the secondary flushing opening may be positioned inside the cavity 904a of the housing 904, between the filter 908 and the inlet conduit 902. As such, the flushing fluid can flow from the drainage device 900 via the secondary flushing opening before reaching the inlet conduit 902. A valve may be employed to close the secondary flushing opening during normal operation of the drainage device, i.e., aqueous humor flows through the inlet conduit 902, the cavity 904a, and the outlet conduit 906 according to pressures within physiologic range. During flushing, however, the pressures associated with the flow of the flushing fluid exceed the physiologic range and cause the valve to open, thereby allowing the flushing fluid to flow through the secondary flushing opening rather than the inlet conduit 902. This mechanism allows for the clogging material to exit the device without over-pressurizing the device or eye by entering the anterior chamber.
In some embodiments, additional disruption act(s) may be optionally employed to disrupt (or break up) the clogging material on the filter 908 and/or in the inlet conduit 902 prior to applying the flushing fluid. For instance, a laser burst, sonication, ultrasound, heat, and/or a bioinert solution for dissolving the material may be directed at the clogging material.
In some cases, drainage devices may include microbeads that encapsulate proteases. The microbeads may be disposed at or near the filter 908 or the inlet conduit 902, e.g., in the cavity 904a between the filter 908 and the inlet conduit 902. A laser burst, sonication, ultrasound, heat, and/or other activating element may be directed to the microbeads to release the proteases and disrupt the clogging material.
In other cases, drainage devices may include an energy amplifying material, such as a piezoelectric material, disposed at or near the filter 908 or the inlet conduit 902. The energy amplifying material can amplify a sonic, ultrasound, mechanical, and/or electromagnetic signal applied to the filter 908 and/or the inlet conduit 902. The amplified signal enhances the disruption of the clogging material on the filter 908 and/or in the inlet conduit 902.
In embodiments above, elements of the drainage devices, e.g., the anti-clogging elements 420, 520, 620, can be removed and replaced to clear obstructions at the outlet conduit. In other embodiments, the filter can be removed and replaced to clear obstructions at the filter. For instance,
As
In the example shown in
To remove and replace the filter 1008, the casing 1008a can be withdrawn from the cavity 1004a. For instance, aspects of the housing 1004 may be formed from a flexible material that allows it to become distorted (e.g., twisted, stretched, etc.) to accommodate removal/insertion of the casing 1008a. The outlet conduit 1006, which is accessible from outside the eye, can be manipulated to distort the casing 1008a and modify the fit between the casing 1008a and the cavity 1004a. The resulting distortion allows the casing 1008a to pulled from the cavity 1004a. Alternatively, the drainage device 1000 may include a release plug that can be operated to modify the fit and allow the casing 1008a to be pulled from the cavity 1004a. Or alternatively, the casing 1008a can be broken with laser, ultrasound, or the like to allow the casing 1008a to be pulled from the cavity 1004a.
Once the casing 1008a is withdrawn from the cavity 1004a, the second section 1000b can be separated from the first section 1000a, while the first section 1000a remains implanted in the eye. Indeed, as shown in
Alternatively, the filter 1008 can be treated to remove the clogging material, and the second section 1000b can be reconnected to the implanted first section 1000a to allow further use of the drainage device 1000. Alternatively, the second section 1000b with the clogged filter 1008 can be replaced with a new second section, and the new second section can be connected to the implanted first section 1000a to allow further use of the drainage device 1000.
In
Embodiments may also include more than one inlet conduit or more than one outlet conduit. Such embodiments provide approaches for addressing clogging. For instance,
As shown in
As described above, proteins in the flow of aqueous humor can collect on the filter 1108 and cause obstructions at the filter 1108. For the first flow path, such obstructions occur in the first section 1108a of the filter 1108. When the drainage device 1100 cannot function effectively due to obstructions in the first section 1108a, the plug 1101 can be removed to open the second flow path. With the opening of the second flow path, aqueous humor can flow alternatively through the second section 1108b of the filter 1108 and the second outlet conduit 1107. Thus, the second flow path provides a backup flow path in case the first flow path becomes clogged.
The filter 1108 may include a casing 1108c, which allows the filter 1108 to be removed and replaced when clogged. For instance, as shown in
Initially, a first plug 1201a may block the first outlet conduit 1206 and a second plug 1201b may block the second outlet conduit 1207. The first plug 1201a may be removed to allow the drainage device 1200 to drain aqueous humor via the first flow path, while the second plug 1201b remains in place to keep the second flow path closed. As described above, proteins in the flow of aqueous humor can collect on the filter 1208 and cause obstructions at the filter 1208. For the first flow path, such obstructions occur in the first section of the filter 1208. When the drainage device 1200 cannot function effectively due to obstructions in the first section, the plug can be selectively dissolved by a laser burst, ultrasound, heat, a bioinert solution, or the like to open the second flow path. This allows the drainage device 1200 to drain aqueous humor alternately via the second flow path. The second flow path provides a backup flow path in case the first flow path becomes clogged.
Alternatively,
Initially, a plug may block the opening to the second inlet conduit 1303 to keep the second flow path closed. As such, the drainage device 1300 drains aqueous humor via the first flow path. As described above, proteins in the flow of aqueous humor can collect on the filter 1308 and cause obstructions at the filter 1308. For the first flow path, such obstructions occur in the first section of the filter 1308. When the drainage device 1300 cannot function effectively due to obstructions in the first section, the plug can be selectively dissolved by a laser burst, ultrasound, heat, a bioinert solution, or the like to open the second flow path. This allows the drainage device 1300 to drain aqueous humor alternately via the second flow path. Thus, the second flow path provides a backup flow path in case the first flow path becomes clogged.
In general, as shown in
Alternatively, rather than blocking or opening conduits to select a flow path through an unclogged region of a filter, material may be applied to regions of the filter and the material may be selectively removed to allow flow through one or more particular unclogged regions. The material may be selectively dissolved by a laser burst, ultrasound, heat, a bioinert solution, or the like. In some embodiments, the material may be applied as a sheath over the filter and the sheath can be moved via a magnet to open flow through a region of the filter.
Alternatively, a drainage device may include a housing with multiple chambers that are separated by barriers and aligned with different respective regions of a filter. The barriers, however, include valves that can open channels through the barriers and allow fluid to flow between the chambers. For instance, the drainage device may initially employ a first flow path where aqueous humor flows from an inlet conduit into a first chamber and through a corresponding first region of the filter. If the first region of the filter becomes clogged, the pressure in the first chamber increases. In response to the increased pressure, a valve may open a channel between the first chamber and a second chamber. As such, the aqueous humor can flow from the first chamber to the second chamber. The second chamber is aligned with a second region of the filter. If the second region is unclogged, the aqueous humor can flow from the second chamber and through the second region. If the second region is or becomes clogged and the pressure in the second chamber increases, another valve may respond by opening a channel between the second chamber and a third chamber to allow flow through a third region of the filter, and so on.
Accordingly, aspects of the present disclosure provide approaches for preventing and/or removing the accumulation of obstructive material in different parts or aspects of implantable drainage devices.
While the present disclosure has been described with reference to one or more particular embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present disclosure. Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the invention. It is also contemplated that additional embodiments according to aspects of the present disclosure may combine any number of features from any of the embodiments described herein.
This application claims priority to and the benefit of U.S. Provisional Application No. 62/633,158, filed Feb. 21, 2018, the contents of which are incorporated entirely herein by reference.
Number | Date | Country | |
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62633158 | Feb 2018 | US |