Patent Publication Number: US-2021177657-A1

Title: Ocular device for treating glaucoma and related minimally invasive glaucoma surgery method

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/726,482 filed Sep. 4, 2018, which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD OF INVENTION 
     The technology of the present disclosure relates generally to an implantable ocular device for treating glaucoma, and a related surgical procedure for implanting the ocular device and using the device for the treatment of glaucoma. 
     BACKGROUND 
     It is estimated that approximately three million people in the United States have glaucoma, and more than one hundred thousand people are blind from glaucoma. Glaucoma is the second leading cause of blindness in adult Americans age eighteen to sixty-five and the leading cause of blindness in African Americans. 
     Glaucoma is an optic neuropathy, or a disorder of the optic nerve, that is characterized by an elevated intraocular pressure. An increase in intraocular pressure may result in changes in the appearance (“cupping”) and function (“blind spots”) in the visual field of the optic nerve. If the pressure remains high enough for a long enough period of time, total vision loss may occur. 
     The eye is a hollow structure that contains a clear fluid called aqueous humor. Aqueous humor is continuously produced in the posterior chamber of the eye by the ciliary body. The aqueous humor passes around the lens, through the pupillary opening in the iris and into the anterior chamber of the eye. Once in the anterior chamber, the aqueous humor drains out principally through a canalicular route that involves the trabecular meshwork and Schlemm&#39;s canal. The trabecular meshwork and Schlemm&#39;s canal are located at a junction between the iris and the cornea called the angle. The trabecular meshwork is composed of collagen beams arranged in a three-dimensional sieve-like structure and lined with a monolayer of trabecular cells. The outer wall of the trabecular meshwork coincides with the inner wall of Schlemm&#39;s canal, which is a tube-like structure that runs around the circumference of the cornea. 
     The aqueous humor, while being filtered, travels through the trabecular meshwork into the Schlemm&#39;s canal, then from there through a series of collecting channels and reaches the episcleral venous system to be absorbed. In a healthy individual, aqueous humor production is approximately equal to aqueous humor outflow, and the intraocular pressure therefore remains fairly constant in the 10 to 21 mmHg range. High pressure develops in an eye because of an internal fluid imbalance. In glaucoma, the resistance through the canalicular outflow system is higher than normal causing reduced outflow, thereby causing an internal fluid imbalance and resulting in an increased pressure. In particular, the drainage angle formed by the cornea and the iris remains open, but the microscopic drainage channels in the trabecular meshwork are at least partially obstructed. Other forms of glaucoma may involve decreased outflow through the canalicular pathway due to mechanical blockage, inflammatory debris, cellular blockage and the like. 
     When the drainage system does not function properly, the aqueous humor cannot filter out of the eye at its normal rate. As the fluid builds up, the intraocular pressure within the eye increases. The increased intraocular pressure compresses the axons of the optic nerve, which carries vision signals from the eye to the brain, and also may compromise the vascular supply to the optic nerve. Damage to the optic nerve is painless and slow, and a vision loss can occur before a person is even aware of a problem. 
     There are various conventional ways of treating glaucoma. For example, eye and systemic medications are used to treat glaucoma by decreasing the production of aqueous humor or increasing its drainage from the eye. 
     Surgical treatment may be performed when medications fail to lower the intraocular pressure. For example, surgical procedures may be used to open up the anatomically closed drainage pathways of the aqueous humor to outside the eye. A trabeculectomy is a surgical procedure that creates a pathway for aqueous humor to escape to the surface of the eye. The anterior chamber is entered beneath the scleral flap and a section of deep sclera and trabecular meshwork is excised. Post-operatively, the aqueous humor passes through the resulting hole and collects in an elevated space (subconjunctival reservoir) beneath the conjunctiva. The fluid then is either absorbed through blood vessels in the conjunctiva or traverses across the conjunctiva into the tear film. A deficiency of such procedure is that as the formed bleb is extremely thin, many times it can fail or erupt allowing a pathway for bacteria that normally live on the surface of the eye and eyelids to get into the eye. 
     Another surgical procedure involves the use of an aqueous shunt. A full thickness hole is made into the eye at the limbus, usually with a needle. The shunt is inserted into the eye through this hole and aqueous humor drains out to the surface of the eye. The tube is attached to a plate and this pate is placed underneath the extraocular muscles. The plate helps to create a reservoir again underneath the conjunctiva to where the aqueous humor drains. Many complications are associated with aqueous shunts. A thickened wall of scar tissue may resist outflow and limit the reduction in eye pressure. The bleb may not form quickly or not at all, resulting in an unrestricted flow through the shunt to the outer surface causing too low of an intraocular pressure that can damage the eye in different ways that could lead to loss of function and sight. As such shunts may erode through the overlying tissues creating an opening to the surface of the eye, a pathway is created for bacteria to get into the eye and endophthalmitis can occur. 
     Laser surgery is a surgical procedure to reduce the intraocular pressure and includes cyclophotocoagulation (reducing the production of aqueous humor by using a laser to burn the part of the eye that produces aqueous humor), iridotomy (use of a laser to make a hole in the iris to allow fluid to flow more freely in the eye), and trabeculoplasty (use of a laser to create holes in the drainage area of the eye to allow fluid to drain more freely). However, laser surgery is complex and suffers from a variety of deficiencies, including reduced effectiveness, inflammation and related complications. 
     Accordingly, standard glaucoma surgeries are major surgeries that have significant deficiencies. While such surgeries are very often effective at lowering eye pressure and preventing progression of glaucoma, they have a long list of potential complications. To overcome such deficiencies, more advanced techniques have been developed which are commonly referred to as “minimally invasive glaucoma surgery” or MIGS. MIGS procedures work by using microscopic-sized equipment and tiny incisions. While they reduce the incidence of complications, some degree of effectiveness is also traded for the increased safety. 
     The MIGS group of operations generally are divided into several categories: miniaturized versions of trabeculectomy; trabecular bypass operations; totally internal or supra-choroidal shunts; milder or gentler versions of laser photocoagulation; and ab-interno canaloplasty (ABiC). Generally, the MIGS procedures work by either bypassing the blocked trabecular meshwork (e.g., trabecular bypass operations and using supra-choroidal shunts), allowing the aqueous humor to drain to another potential space or by opening the Schlemm&#39;s canal and the collector channels (ABiC), or by decreasing the production of the aqueous humor (laser photocoagulation). Because of the advantage of MIGS procedures over more conventional treatments, efforts to improve such procedures are on-going. 
     SUMMARY OF INVENTION 
     The present invention relates to an ocular device and related minimally invasive glaucoma surgery (MIGS) for treating glaucoma with the ocular device. The described technique includes accessing the Schlemm&#39;s canal through a very small guide hole made at the trabecular meshwork. A guide wire, such as for example a suture, probe wire, I-track system or the like, is threaded through the guide hole. A trabecular meshwork bypass device is guided along the guide wire for proper placement for bypassing a blocked portion or portions of the trabecular meshwork. A canaloplasty probing device having a lumen further may be employed to aid insertion of the guide wire and bypass device, and to introduce substances into the trabecular meshwork and/or Schlemm&#39;s canal such as glaucoma medications, anti-inflammatory agents, antibiotic releasing pellets, viscoelastic materials and the like. 
     As the system including the guide wire and bypass device is threaded through the lumen of the probing device (if applicable) or otherwise threaded into the eye through the guide hole, a visualization agent, with or without a viscoelastic substance, is injected into the area in which the bypass device is to be implanted. This allows the Schlemm&#39;s canal and the collector channels to be reopened, and also lubricates and expands the Schlemm&#39;s canal. The visualization agent may be a dye, such as for example fluoresceine, tripan blue, or other suitable dye, or a physical visible agent such as micro-bubbles. The visualization agent may be visualized using any suitable imaging technique, such as for example optical coherence tomography or ultrasound bio-microscopy. Imaging of the visualization agent flowing through the drainage system allows the Schlemm&#39;s canal, trabecular meshwork and the collector channels to be viewed in great detail, which allows the surgeon to further identify the clogged areas of the trabecular meshwork/Schlemm&#39;s canal/collector channels versus open channels to ascertain an optimal location for insertion of the bypass device to either bypass the problem or to open the blocked area. 
     The bypass device includes tips that penetrate through the trabecular meshwork to provide open channels through the trabecular meshwork for draining the aqueous humor. As the Schlemm&#39;s canal walls are opened by the viscoelastic and/or the guide wire, this allows easier penetration of the tips of the bypass device through the trabecular meshwork into the Schlemm&#39;s canal. Once the bypass device is properly placed, then the guide wire and any canaloplasty probing device are retrieved while leaving the bypass device in place. 
     In exemplary embodiments, the bypass device has an open tubular structure that is laser cut with pronged features to create open tented holes through the trabecular meshwork. The tubular structure may include multiple arrow-shaped tangs that are formed within a tubular base, with the tubular base having a curvature that approximates a curvature of the iridocorneal angle structures. One or more pairs of adjacent tangs may be flexed at the desired locations to form the tents that are inserted through the trabecular meshwork. In particular, the tents may be formed at clogged locations of the trabecular meshwork as determined by the visualization techniques described above. A heat setting process may be employed to securely implant the tents of the bypass device through the trabecular meshwork. The heat setting process may constitute a lateral angle heat set to impart side-to-side forces during release of the guide wire to create tissue engagement with the trabecular meshwork. In an exemplary embodiment, the arrow-shaped tangs that are used to form the tents may be offset arrows, which may improve holding of the bypass device to the trabecular meshwork. 
     As an alternative or addition to implantation of a bypass device, the guide wire and canaloplasty probing device may be used to insert glaucoma medication, anti-inflammatory agents, antibiotic releasing pellets, and the like into the trabecular meshwork and/or Schlemm&#39;s canal for further success in intra-ocular pressure reduction, and for prevention of inflammation and related complications and infections. In addition, a second guide wire can be threaded through the lumen of the canaloplasty probing device and/or around the canaloplasty probing device to help maintain the efficacy of the Schlemm&#39;s canal opening. Studies of prior techniques have demonstrated that de-clogging and maintaining the efficacy of the Schlemm&#39;s canal opening aids with long term reduction of intra-ocular pressure. 
     An aspect of the invention, therefore, is a bypass device that can be implanted into a body tissue to provide fluid channels through the body tissue. In exemplary embodiments, the bypass device includes an open tubular base, and a plurality of pronged features attached to the open tubular base, the pronged features being reconfigurable from a first position to a second position. In the first position the pronged features extend longitudinally along a plane of the open tubular base, and the pronged features are reconfigurable to the second position by flexing the pronged features relative to the tubular base, such that in the second position the pronged features are configured for insertion through the body tissue. The pronged features are associated in pairs, with individual pronged features of a pair of pronged features being attached to each other via a web, and the pronged features are reconfigurable from the first position to the second position by flexing opposing pronged features of the pair about the web to form tent structures. The pronged features may be configured as multiple arrow-shape tangs that are formed within the tubular base, and individual tangs within a pair of tangs may be offset relative to each other along the longitudinal axis of the open tubular base. 
     Another aspect of the invention is a minimally invasive glaucoma surgery (MIGS) for treating glaucoma using a method of implanting a bypass device into the trabecular meshwork to define a fluid flow channel that permits aqueous humor to pass through trabecular meshwork and into Schlemm&#39;s canal. In exemplary embodiments, the MIGS method includes the steps of: providing a bypass device according to any of the embodiments for bypassing a drainage system of an eye including Schlemm&#39;s canal, trabecular meshwork, and collector channels; forming a guide hole to access a Schlemm&#39;s canal at a trabecular meshwork of an eye; inserting the bypass device through the guide hole and positioning the bypass device within the Schlemm&#39;s canal adjacent to the trabecular meshwork; reconfiguring a portion of the pronged features from the first position to the second position to form one or more tent structures; and inserting the one or more tent structures of the bypass device into the trabecular meshwork, wherein the one or more tent structures form tent holes through the trabecular meshwork to define fluid flow channels through the trabecular meshwork. The tenting effect is desired to keep the Schlemm&#39;s canal from collapsing or closing, and to maintain the aqueous humor flow through the formed trabecular meshwork openings to the Schlemm&#39;s canal and then to the collector channels. The positioning of the bypass device may be aided with the use of a guide wire, and the guide wire and/or bypass device may be inserted through a lumen of a canaloplasty probing device. 
     Another aspect of the invention is a method of positioning an intraocular device including the steps of: forming a guide hole to access a Schlemm&#39;s canal at a trabecular meshwork of an eye; inserting a guide wire through the guide hole; and positioning the intraocular device relative to the guide wire. In exemplary embodiments, the intraocular device is a canaloplasty device having a lumen, and the method further comprises introducing one or more substances into the Schlemm&#39;s canal through the lumen. A second guide wire may be threaded through the lumen, or inserted around the canaloplasty device, and the second guide wire aids in maintaining efficacy of the Schlemm&#39;s canal opening. 
     These and further features of the present invention will be apparent with reference to the following description and attached drawings. In the description and drawings, particular embodiments of the invention have been disclosed in detail as being indicative of some of the ways in which the principles of the invention may be employed, but it is understood that the invention is not limited correspondingly in scope. Rather, the invention includes all changes, modifications and equivalents coming within the spirit and terms of the claims appended hereto. Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a drawing depicting a cross-sectional view of an eye. 
         FIG. 2  is a drawing depicting an enlarged cross-sectional view of an anterior chamber angle of the eye of  FIG. 1 . 
         FIG. 3  is a drawing depicting an exemplary bypass device in accordance with embodiments of the present invention. 
         FIG. 4  is a drawing depicting another view of the exemplary bypass device of  FIG. 3 . 
         FIG. 5  is a drawing depicting a close-up view of a tent structure of the bypass device depicted in  FIGS. 3 and 4 . 
         FIG. 6  is a drawing depicting another configuration of an exemplary bypass device in accordance with embodiments of the present invention. 
         FIG. 7  is a drawing depicting another configuration of an exemplary bypass device in accordance with embodiments of the present invention. 
         FIG. 8  is a drawing depicting a close-up view of bent tangs of the bypass device depicted in  FIG. 7 , which may be employed to form a tent structure. 
         FIG. 9  is a drawing depicting another configuration of an exemplary bypass device in accordance with embodiments of the present invention. 
         FIG. 10  is a drawing depicting a close-up view of a tent structure of the bypass device depicted in  FIG. 9 . 
         FIG. 11  is a drawing depicting a close-up view of a variation of a tent structure of a bypass device in accordance with embodiments of the present invention. 
         FIG. 12  and  FIG. 13  are drawings depicting a first method of inserting a bypass device in accordance with embodiments of the present invention. 
         FIG. 14  is a drawing depicting a second method of inserting a bypass device in accordance with embodiments of the present invention. 
         FIG. 15  is a drawing depicting an exemplary insertion instrument for inserting a bypass device in accordance with embodiments of the present invention. 
         FIG. 16  is a drawing depicting an insertion operation of a bypass device which may be performed using the insertion instrument of  FIG. 15 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Embodiments will now be described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. It will be understood that the figures are not necessarily to scale. 
       FIG. 1  is a drawing depicting a cross-sectional view of an eye  10 , and  FIG. 2  is a drawing depicting an enlarged cross-sectional view of an anterior chamber angle of the eye of  FIG. 1 , including the relative anatomical locations of the trabecular meshwork, the anterior chamber, and Schlemm&#39;s canal. Collagenous tissue known as sclera  11  covers the eye  10  except the portion covered by the cornea  12 . The cornea  12  is a transparent tissue that focuses and transmits light into the eye, and the pupil  14  is the circular hole in the center of the iris  13  (colored portion of the eye). The cornea  12  merges into the sclera  11  at a juncture referred to as the limbus  15 . The ciliary body  16  begins internally in the eye and extends along the interior of the sclera  11  and becomes the choroid  17 . The choroid  17  is a vascular layer of the eye underlying the retina  18 . The optic nerve  19  transmits visual information to the brain and is progressively destroyed by glaucoma as described above. 
     The anterior chamber  20  of the eye  10 , which is bound anteriorly by the cornea  12  and posteriorly by the iris  13  and lens  26 , is filled with the aqueous humor. As detailed above, aqueous humor is a fluid produced primarily by the ciliary body  16  and reaches the anterior chamber angle  25  formed between the iris  13  and the cornea  12  through the pupil  14 . In a normal eye, the aqueous humor is removed through the trabecular meshwork  21 . Aqueous humor passes through the trabecular meshwork  21  into Schlemm&#39;s canal  22  and through the aqueous veins  23  which merge with blood-carrying veins and into venous circulation. Intraocular pressure of the eye  10  is maintained by the intricate balance of secretion and outflow of the aqueous humor in the manner described above. Glaucoma is characterized by the excessive buildup of aqueous humor in the anterior chamber  20 , which produces an increase in intraocular pressure that ultimately damages and then destroys the optic nerve. 
     The present invention relates to an intraocular bypass device and related minimally invasive glaucoma surgery (MIGS) for treating glaucoma with an ocular bypass device. In exemplary embodiments, the bypass device has an open tubular structure that is laser cut with pronged features to create open tented holes through the trabecular meshwork. The tubular structure may include multiple arrow-shaped tangs that are formed within a tubular base, with the tubular base having a curvature that approximates a curvature of the iridocorneal angle structures. One or more pairs of adjacent tangs may be flexed at the desired locations to form the tents that are inserted through the trabecular meshwork. In particular, the tents may be formed at clogged locations of the trabecular meshwork as determined by the visualization techniques described above. A heat setting process may be employed to implant the tents of the bypass device through the trabecular meshwork. The heat setting process may constitute a lateral angle heat set to impart side-to-side forces during release of the guide wire to create tissue engagement. In an exemplary embodiment, the arrow-shaped tangs that are used to form the tents may be offset arrow tangs, which may improve holding upon implantation. 
       FIG. 3  is a drawing depicting an exemplary bypass device  30  in accordance with embodiments of the present invention, and  FIG. 4  is a drawing depicting another view of the exemplary bypass device of  FIG. 3 . The bypass device  30  includes an open tubular base  32  that is formed with a curvature approximating the curvature of typical iridocorneal angle structures. The bypass device further is formed to include a plurality of pronged features  34  that are attached to the open tubular base and are reconfigurable from a first position to a second position. In the first position, the pronged features  34  generally extend longitudinally along a plane of the tubular base  32 . The pronged features then are reconfigurable from the first position to the second position by flexing the pronged features relative to the tubular base  32 , such that in the second position the pronged features are configured for insertion through a body tissue. For example, the pronged features in the second position may constitute tent structures that operate to create open tented holes through the trabecular meshwork as further detailed below. The bypass device may be formed using any suitable manufacturing process. Examples without limitation include laser cutting, photo-chemical etching, electrical discharge machining (EDM) or micro-machining, and micro-molding out of a plastic substrate. 
     In exemplary embodiments, the pronged features  34  are associated in pairs connected to the tubular base  32  via a web  36 . Individual pronged features of a pair of pronged features thus are attached to each other via the web  36 . Further as to each associated pair, the pronged features are reconfigurable from the first position to the second position by flexing opposing pairs of pronged features  32  toward each other about the web  36 . Materials that are used to form the bypass implant include, for example, nitinol, platinum, titanium, stainless steel, gold, silicon, PMMA, polyimide, or like materials. In an exemplary embodiment, the bypass implant material is nitinol and the shape is heat set in three stages to form the tangs and curvature. A common base fixture may be used for all three heat setting stages, but in a different configuration or orientation, and the heat setting may be achieved at 525° C. for seven minutes per stage. 
     In the example shown in  FIGS. 3 and 4 , an exemplary pair of pronged features  34   a  and  34   b  are flexed around their associated web  36   a  to form a tent structure  38 , which in turn is used to form the referenced tented holes through the trabecular meshwork (again as further detailed below). Although only one tent structure  38  is shown in these figures, any suitable number of tents  38  may be formed as desired for any particular circumstance, and thus a portion of the pronged features may be reconfigured to the second position while a portion of the pronged features are maintained in the first position. In general, tent structures may be formed to be positioned at clogged locations of the trabecular meshwork as determined by the visualization techniques. In this manner, fluid can pass through the clogged portion(s) of the trabecular meshwork through the tented holes formed by the tent structures  38 . 
       FIG. 5  is a drawing depicting a close-up view of the tent structure  38  of the bypass device depicted in  FIGS. 3 and 4 . In exemplary embodiments, the pronged features  34  are configured as multiple arrow-shaped tangs that are formed within the tubular base  32 . Each of the tangs  34  includes a neck  40  that is flexible relative to the tubular base  32 , and an arrow-shaped head  42  that is flexible relative to the neck  40 . The flexing of the arrow-shaped heads  42  relative to the neck  40  permits optimal positioning of the tent structure  38  for proper insertion through the trabecular meshwork to form the tented holes therethrough. In addition, the arrow shape of the heads  42  provides a wedge configuration for penetration of the tent structure  38  through the trabecular meshwork to form said tented holes. Once implanted within the trabecular meshwork, the tent structures  38  each defines a fluid flow channel that permits aqueous humor to pass through clogged portion(s) of the trabecular meshwork and into Schlemm&#39;s canal. 
     With such a configuration, one or more openings are provided in fluid communication with one or more intrinsic internal chambers of the device. The internal chamber(s) are also in fluid communication with one or more openings which are likewise in fluid communication with Schlemm&#39;s canal or other ocular areas so as to allow passage of fluid from the anterior chamber of the eye. 
       FIG. 6  is a drawing depicting another configuration of an exemplary bypass device  50  in accordance with embodiments of the present invention. Similarly, as in the previous embodiment, the bypass device  50  includes an open tubular base  52  that is laser cut with a curvature approximating the curvature of typical iridocorneal angle structures. The bypass device  50  further is laser cut to include pronged features  54  that are reconfigurable from a first position to a second position by flexing the pronged features to form tent structures in a comparable manner as described above. The pronged features  54  also may be configured as multiple arrow-shaped tangs that are formed within the tubular base  52 . Each of the tangs  54  includes a neck  56  that is flexible relative to the tubular base  52 , and an arrow-shaped head  58  that is flexible relative to the neck  56  for optimal positioning of tent structures formed with the tangs  54  with respect to clogged portions of the trabecular meshwork. As compared to the previous embodiment, in the embodiment of  FIG. 6  the arrow-shaped tangs  54  that are used to form the tent structures are offset arrow tangs, i.e., opposing tangs  54   a  and  54   b  are offset relative to each other along the longitudinal axis of the tubular base  52 . Accordingly, individual tangs within a pair of opposing tangs are offset relative to each along the longitudinal axis of the open tubular base. The offset tang configuration of  FIG. 6  may improve holding of the bypass device  52  within the trabecular meshwork upon implantation. Also, the tangs can be made in different sizes and shapes, and/or oriented in different directions, to provide a better positioning and secure hold of the device to stay in place after insertion. 
       FIG. 7  is a drawing depicting another configuration of an exemplary bypass device  60  in accordance with embodiments of the present invention. Similarly as in the previous embodiments, the bypass device  60  includes an open tubular base  62  that is laser cut with a curvature approximating the curvature of typical iridocorneal angle structures. The bypass device  60  further is laser cut to include pronged features  64  that are reconfigurable from a first position to a second position by flexing the pronged features to form tent structures in a comparable manner as described above. The pronged features  64  also may be configured as multiple arrow-shaped tangs that are formed within the tubular base  62 . Each of the tangs  64  includes a neck  66  that is flexible relative to the tubular base  62 , and an arrow-shaped head  68  that is flexible relative to the neck  66  for optimal positioning of tent structures formed with the tangs  64  with respect to clogged portions of the trabecular meshwork. Similarly as in the previous embodiment, in the embodiment of  FIG. 7  the arrow-shaped tangs  64  that are used to form the tent structures also are offset arrow tangs, i.e., opposing tangs  64   a  and  64   b  are offset relative to each other along the longitudinal axis of the tubular base  62 . The embodiment  60  of  FIG. 7  differs from the embodiment  50  of  FIG. 6  in that the tangs  64  are longer in the longitudinal direction as compared to the tangs  54  of  FIG. 6 . Accordingly, tent structures formed from the tangs  64  of  FIG. 7  will extend father from the tubular base as compared to the tangs  54  of  FIG. 6 . 
       FIG. 8  is a drawing depicting a close-up view of bent tangs  65  of the bypass device  60  depicted in  FIG. 7 , which may be employed to form a tent structure. Similarly as described above in connection with previous embodiments, the flexing of the arrow-shaped heads  68  relative to the neck  66  permits optimal positioning of the tent structure  65  for proper insertion through the trabecular meshwork to form the tented holes therethrough. In addition, the arrow shape of the heads  68  provide a wedge configuration for penetration of the tent structure through the trabecular meshwork to form the referenced tented holes. Once implanted within the trabecular meshwork, the tent structures each defines a fluid flow channel that permits aqueous humor to pass through clogged portion(s) of the trabecular meshwork and into Schlemm&#39;s canal. 
       FIG. 9  is a drawing depicting another configuration of an exemplary bypass device  70  in accordance with embodiments of the present invention.  FIG. 10  is a drawing depicting a close-up view of a tent structure  75  of the bypass device depicted in  FIG. 9 . Similarly as in the previous embodiments, the bypass device  70  includes an open tubular base  72  that is laser cut with a curvature approximating the curvature of typical iridocorneal angle structures. The bypass device  70  further is laser cut to include pronged features  74  that are reconfigurable from a first position to a second position by flexing the pronged features to form tent structures in a comparable manner as described above. The pronged features  74  also may be configured as multiple arrow-shaped tangs that are formed within the tubular base  72 . Each of the tangs  74  includes a neck  76  that is flexible relative to the tubular base  72 , and an arrow-shaped head  78  that is flexible relative to the neck  76  for optimal positioning of tent structures  75  formed with the tangs  74  with respect to clogged portions of the trabecular meshwork. The embodiment  70  of  FIGS. 9 and 10  differs from previous embodiments in that the tangs  74  may include a tapered edge  73  that runs from the tubular base  72  to the arrow-shaped head  78 . The tapered edges may aid in manipulation and bending to form the tent structures  75 . 
       FIG. 11  is a drawing depicting a close-up view of a variation of a tent structure  85  of a bypass device  80  in accordance with embodiments of the present invention. Similarly as in the previous embodiments, the bypass device  80  includes an open tubular base  82  that is laser cut with a curvature approximating the curvature of typical iridocorneal angle structures. The bypass device  80  further is laser cut to include pronged features  84  that are reconfigurable from a first position to a second position by flexing the pronged features to form tent structures in a comparable manner as described above. The pronged features  84  also may be configured as multiple arrow-shaped tangs that are formed within the tubular base  82 . Each of the tangs  84  includes a neck  86  that is flexible relative to the tubular base  82 , and an arrow-shaped head  88  that is flexible relative to the neck  86  for optimal positioning of tent structures  85  formed with the tangs  84  with respect to clogged portions of the trabecular meshwork. The embodiment  80  of  FIG. 11  differs from previous embodiments in that opposing tangs  84  are oriented at an angle  87  relative to each other upon formation of the tent structure  85 . The angled structure may be incorporated into any of the previous embodiments, and may provide enhanced retention of the bypass device within the ocular tissue. 
       FIGS. 12 and 13  are drawings depicting a first method of inserting a bypass device in accordance with embodiments of the present invention. In this example, a bypass device  90  is guided during insertion within a sheath  92 . The bypass device  90  may be configured in accordance with any of the embodiments. As shown in  FIG. 12 , the sheath  92  may include a shoulder  94  that acts to curl and otherwise shape tangs  96  of the bypass device to form the tent structures.  FIG. 12  illustrates a tent position under operation of the shoulder  94  of the sheath  92 , and the bypass device may be inserted through the trabecular meshwork while in this tent position. The tangs  96  of the bypass device may have properties of a spring, and thus the curling force acts against a spring action that biases the tangs outward from the tent structure shown in  FIG. 12 . Accordingly, as shown in  FIG. 13 , once the curling force applied by the shoulder of the sheath is removed, the spring action of the tangs  96  results in the tangs restoring to a set position in which the arrow heads  98  of the tangs are spaced farther apart as compared to the tent position of  FIG. 12 . In operation of the bypass device  90  once implanted, the restoration to the set position widens the bypass hole through the trabecular meshwork, which aids in the draining of fluid. 
       FIG. 14  is a drawing depicting a second method of inserting a bypass device in accordance with embodiments of the present invention. In this embodiment, the sheath  92  is equipped with a coil spring  95  rather than the shoulder  94  of the previous embodiment. As the bypass device  90  is moved into position, the turns of the coil spring  95  interact against the tangs  96  to form the tent configuration as shown in the figure. When the sheath portion with coil spring  95  is removed from interaction with the tangs  96 , similarly as in the previous embodiment, the curling force applied by the coil spring of the sheath is removed, and the spring action of the tangs  96  results in the tangs restoring to the set position illustrated in  FIG. 13 . Again, the restoration to the set position widens the bypass hole through the trabecular meshwork, which aids in the draining of fluid. 
     Another aspect of the invention is a minimally invasive glaucoma surgery (MIGS) for treating glaucoma using a method of implanting a bypass device into the trabecular meshwork to define a fluid flow channel that permits aqueous humor to pass through trabecular meshwork and into Schlemm&#39;s canal. As referenced above, one or more pairs of adjacent pronged features may be reconfigured at the desired locations, and in particular at clogged locations of the trabecular meshwork, to form the tent structures that are inserted into the trabecular meshwork to form the tent holes through the trabecular meshwork. In particular, the tent structures may be formed at clogged locations of the trabecular meshwork as determined by visualization techniques. The spring action of the tangs may be used as a widening step to widen the holes through the trabecular meshwork to enhance the fluid flow. A heat setting process may be employed to securely implant the tent structures of the bypass device through the trabecular meshwork, such that the tent structures form the referenced tent holes for fluid flow through the trabecular meshwork. The implantation of the bypass device may be aided by using a guide wire sheath to position the bypass device at the desired location within the trabecular meshwork. The heat setting process may constitute a lateral angle heat set to impart side-to-side forces during release of the guide wire to create tissue engagement. 
     In exemplary embodiments, therefore, the MIGS method includes the steps of: providing a bypass device for bypassing a drainage system of an eye including Schlemm&#39;s canal, trabecular meshwork, and collector channels according to any of the embodiments; forming a guide hole to access a Schlemm&#39;s canal at a trabecular meshwork of an eye; inserting the bypass device through the guide hole and positioning the bypass device within the Schlemm&#39;s canal adjacent to the trabecular meshwork; reconfiguring a portion of the pronged features from the first position to the second position to form one or more tent structures; and inserting the one or more tent structures of the bypass device into the trabecular meshwork, wherein the one or more tent structures form tent holes through the trabecular meshwork to define fluid flow channels through the trabecular meshwork. The positioning of the bypass device may be aided with the use of a guide wire. 
     In an exemplary embodiment, an incision may be made to form a guide hole to provide access to a portion of the Schlemm&#39;s canal. The bypass device, and optionally a guide wire sheath, are inserted through the guide hole such that the curvature of the bypass device is generally aligned with the curvature of the Schlemm&#39;s canal. The guide wire may be used to aid in proper positioning of the bypass device, such that tent structures are optimally positioned relative to clogged portions of the trabecular meshwork as determined by any suitable visual technique. The guide wire particularly may be suitable for use when a larger number of tent structures, such as three or more for example, are employed. Once the bypass device is properly positioned, a heat setting process may be employed to secure the bypass device within the tissue of the trabecular meshwork. As referenced above, the heat setting process may constitute a lateral angle heat set to impart side-to-side forces during release of the guide wire to create tissue engagement of the bypass device with the trabecular meshwork. With such placement, the tent structures each defines a fluid flow channel that permits aqueous humor to pass through trabecular meshwork and into Schlemm&#39;s canal. 
     More specifically, a MIGS glaucoma procedure includes accessing the Schlemm&#39;s canal through a very small guide hole made at the trabecular meshwork. A guide wire, such as for example a suture, probe wire, I-track system or the like, is threaded through the guide hole. The trabecular meshwork bypass device according to any of the embodiments is guided along the guide wire for proper placement for bypassing a blocked portion or portions of the trabecular meshwork. A canaloplasty probing device having a lumen further may be employed to aid insertion of the guide wire and bypass device, and to introduce substances into the trabecular meshwork and/or Schlemm&#39;s canal such as glaucoma medication, anti-inflammatory agents, antibiotic releasing pellets, and the like. 
     As the system including the guide wire and bypass device is threaded through the lumen of the canaloplasty probing device (if applicable), or otherwise threaded into the eye through the guide hole, a visualization agent with or without a viscoelastic substance is injected in the area in which the bypass device is to be implanted. This allows the Schlemm&#39;s canal and the collector channels to be reopened, and also lubricates and expands the Schlemm&#39;s canal to facilitate implantation of the bypass device. The visualization agent may be a dye, such as for example fluoresceine, tripan blue, or other suitable dye, or a physical visible agent such as micro-bubbles. The visualization agent may be visualized using any suitable imaging technique, such as for example optical coherence tomography or ultrasound bio-microscopy or direct visualization via magnification. Imaging of the visualization agent flowing through the collector channels allows the surgeon to further identify the clogged areas of the trabecular meshwork/Schlemm&#39;s canal/collector channels versus open structures to ascertain an optimal location for insertion of the bypass device. 
     The bypass device is inserted through the trabecular meshwork, whereby the tent holes are formed through the trabecular meshwork to provide open channels for draining the aqueous humor. As the Schlemm&#39;s canal walls are opened by the viscoelastic and/or the guide wire, this allows easier penetration of the tips of the bypass device through the trabecular meshwork into the Schlemm&#39;s canal. Once the bypass device is properly placed, then the guide wire and any canaloplasty probing device are retrieved while leaving the bypass device in place. In one exemplary embodiment, the guide wire is inserted into a superior portion of the Schlemm&#39;s canal, and the bypass device thus is positioned inferior to the guide wire. Alternatively, the guide wire may be inserted into an inferior portion of the Schlemm&#39;s canal, and the bypass device thus is positioned superior to the guide wire. 
       FIG. 15  is a drawing depicting an exemplary insertion instrument  110  for inserting a bypass device in accordance with embodiments of the present invention.  FIG. 16  is a drawing depicting the insertion operation of a bypass device  90  (which may be configured according to any of the embodiments) which may be performed using the insertion instrument  110  of  FIG. 15 . It will be appreciated that the insertion instrument  110  is a suitable example, and other suitable instruments may be employed. As illustrated in  FIG. 15 , the exemplary insertion instrument  110  includes a handle portion  112  with a slider  114  that may be used to drive the bypass device into position within an eye  116 . For insertion, a bypass device  90  according to any of the embodiments is housed within a sheath  92  that is comparable to the sheath  92  shown in  FIGS. 12-14 , with the sheath  92  acting as a guide wire. The combined sheath and bypass device are threaded through a curved cannula  118  that houses the bypass device until deployment at the desired position within the eye. A groove in the cannula  118  orients the tangs of the bypass device for implanting. Using the slider  114 , a surgeon advances the bypass device through the cannula  118  to a curved end portion  120  of the cannula. 
     As best shown in  FIG. 16 , the curved end portion  120  of the cannula  118  provides support to push the bypass device  90  into the trabecular meshwork  122 . In particular, the curved shape allows the cannula to provide a force vector in line with any of the tangs during insertion into the trabecular meshwork.  FIG. 16  illustrates tangs of the bypass device  90  formed into tent structures  124 , with the tent structures  124  being formed for example by one of the methods described above with respect to  FIGS. 12-14 . Once the bypass device  90  is properly positioned and inserted through the trabecular meshwork  122 , the slider  114  is employed to withdraw the sheath  92  through the cannula  118 , leaving the bypass device  90  in place. With the sheath removed, the spring action of the tangs results in restoration of the tent structures to the widened set position configuration of  FIG. 13 , thereby providing effective retention and adequate holes through the trabecular meshwork for fluid draining. 
     An alternative or addition to implantation specifically of a bypass device, comparable principles may be employed by which a guide wire is used to guide positioning of any suitable intraocular device. For example, the guide wire may be employed to guide a canaloplasty probing device to insert glaucoma medication, anti-inflammatory agents, antibiotic releasing pellets, and the like into the trabecular meshwork and/or Schlemm&#39;s canal for further success in intra-ocular pressure reduction, and for prevention of inflammation and related complications and infections. In addition, a second guide wire can be threaded through the lumen of the canaloplasty probing device or around the canaloplasty probing device to help maintain the efficacy of the Schlemm&#39;s canal opening. Studies of prior techniques have demonstrated that de-clogging and maintaining the efficacy of the Schlemm&#39;s canal opening aids with long term reduction of intra-ocular pressure. 
     In addition, although the bypass device has been described specifically in connection with forming fluid channels through the trabecular meshwork as part of a MIGS glaucoma treatment, comparable principles may be applicable to forming fluid channels through any suitable body tissue. Accordingly, use of the bypass device and the related methods of implanting the bypass device are not limited to the trabecular meshwork and components of the eye, but may be employed in other circumstances in which it desired to form fluid channels through a body tissue. 
     An aspect of the invention, therefore, is a bypass device that can be implanted into a body tissue to provide fluid channels through the body tissue. In exemplary embodiments, the bypass device includes an open tubular base, and a plurality of pronged features attached to the open tubular base, the pronged features being reconfigurable from a first position to a second position. In the first position the pronged features extend longitudinally along a plane of the open tubular base, and the pronged features are reconfigurable to the second position by flexing the pronged features relative to the tubular base, such that in the second position the pronged features are configured for insertion through the body tissue. The bypass device may include one or more of the following features, either individually or in combination. 
     In an exemplary embodiment of the bypass device, the pronged features are associated in pairs, with individual pronged features of a pair of pronged features being attached to each other via a web, and the pronged features are reconfigurable from the first position to the second position by flexing opposing pronged features of the pair about the web. 
     In an exemplary embodiment of the bypass device, the pronged features are configured as multiple arrow-shape tangs that are formed within the tubular base. 
     In an exemplary embodiment of the bypass device, each arrow-shaped tang includes a neck that is flexible relative to the tubular base, and an arrow-shape head that is flexible relative to the neck. 
     In an exemplary embodiment of the bypass device, individual tangs within a pair of opposing tangs are offset relative to each other along the longitudinal axis of the open tubular base. 
     In an exemplary embodiment of the bypass device, each individual tang includes a tapered edge that runs from the tubular base to an arrow-shaped head of the tang. 
     In an exemplary embodiment of the bypass device, opposing ends of the pronged features are oriented at an angle relative to each other upon formation of the tent structures. 
     In an exemplary embodiment of the bypass device, the pronged features have a spring action such that when a force creating a respective tent structure is released, the pronged structures restore to a set position in which heads of the pronged structures are spaced farther apart as compared to the tent structure. 
     In an exemplary embodiment of the bypass device, in the second position the pronged features are configured as tent structures. 
     In an exemplary embodiment of the bypass device, the tubular base has a curvature that approximates a curvature of iridocorneal angle structures. 
     In an exemplary embodiment of the bypass device, portions of the pronged features are reconfigured to the second position and portions of the pronged features are maintained in the first position. 
     Another aspect of the invention is a minimally invasive glaucoma surgery (MIGS) for treating glaucoma using a method of implanting a bypass device into the trabecular meshwork to define a fluid flow channel that permits aqueous humor to pass through trabecular meshwork and into Schlemm&#39;s canal. In exemplary embodiments, the MIGS method includes the steps of: providing a bypass device according to any of the embodiments for bypassing a drainage system of an eye including Schlemm&#39;s canal, trabecular meshwork, and collector channels; forming a guide hole to access a Schlemm&#39;s canal at a trabecular meshwork of an eye; inserting the bypass device through the guide hole and positioning the bypass device within the Schlemm&#39;s canal adjacent to the trabecular meshwork; reconfiguring a portion of the pronged features from the first position to the second position to form one or more tent structures; and inserting the one or more tent structures of the bypass device into the trabecular meshwork, wherein the one or more tent structures form tent holes through the trabecular meshwork to define fluid flow channels through the trabecular meshwork. The MIGS method may include one or more of the following features, either individually or in combination. 
     In an exemplary embodiment of the MIGS method, the method further includes performing a visualization technique to locate clogged portions of the drainage system, wherein the bypass device is aligned relative to the trabecular meshwork such that the one or more tent structures are positioned at or adjacent to respective clogged portions of the trabecular meshwork as determined by the visualization technique. 
     In an exemplary embodiment of the MIGS method, the method further includes performing a heat setting process to securely implant the tent structures in the trabecular meshwork. 
     In an exemplary embodiment of the MIGS method, the method further includes inserting a guide wire through the guide hole, positioning the bypass device relative to the guide wire, and removing the guide wire once the bypass device is properly positioned. 
     In an exemplary embodiment of the MIGS method, the guide wire is inserted into a superior portion of the Schlemm&#39;s canal, and the bypass device is positioned inferior relative to the guide wire. 
     In an exemplary embodiment of the MIGS method, the guide wire is inserted into an inferior portion of the Schlemm&#39;s canal, and the bypass device is positioned superior relative to the guide wire. 
     In an exemplary embodiment of the MIGS method, the method further includes performing a heat setting process to securely implant the tent structures in the trabecular meshwork, wherein the heat setting process includes a lateral angle heat set to impart side-to-side forces during release of the guide wire to create tissue engagement of the bypass device with the trabecular meshwork. 
     In an exemplary embodiment of the MIGS method, the method further includes injecting a viscoelastic substance into the Schlemm&#39;s canal to expand the Schlemm&#39;s canal to aid inserting the bypass device. 
     In an exemplary embodiment of the MIGS method, the method further includes inserting a canaloplasty device having a lumen through the guide hole, introducing one or more substances into the Schlemm&#39;s canal through the lumen, and removing the canaloplasty device after inserting the bypass device into the trabecular meshwork. 
     In an exemplary embodiment of the MIGS method, the one or more substances include a guide wire to aid in positioning the bypass device, glaucoma medication, anti-inflammatory agents, and/or antibiotic releasing pellets. 
     Another aspect of the invention is a method of positioning an intraocular device including the steps of: forming a guide hole to access a Schlemm&#39;s canal at a trabecular meshwork of an eye; inserting a guide wire through the guide hole; and positioning the intraocular device relative to the guide wire. In exemplary embodiments, the intraocular device is a canaloplasty device having a lumen, and the method further comprises introducing one or more substances into the Schlemm&#39;s canal through the lumen. A second guide wire may be threaded through the lumen, or inserted around the canaloplasty device, and the second guide wire aids in maintaining efficacy of the Schlemm&#39;s canal opening. 
     Although the invention has been shown and described with respect to a certain embodiment or embodiments, equivalent alterations and modifications may occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein exemplary embodiment or to embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.