Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
  • A61F9/007—Methods or devices for eye surgery
  • A61F9/00781—Apparatus for modifying intraocular pressure, e.g. for glaucoma treatment
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/14—Eye parts, e.g. lenses, corneal implants; Implanting instruments specially adapted therefor; Artificial eyes

Definitions

• the present invention is generally directed to a surgical treatment for glaucoma, and relates more particularly to a device and method for continuously decompressing elevated intraocular pressure in eyes affected by glaucoma by diverting aqueous humor from the anterior chamber of the eye into Schlemm's canal where postoperative patency can be maintained with an indwelling shunt which can be surgically placed to connect the canal with the anterior chamber.
• Glaucoma is a significant public health problem, because glaucoma is a major cause of blindness.
• the blindness that results from glaucoma involves both central and peripheral vision and has a major impact on an individual's ability to lead an independent life.
• Glaucoma is an optic neuropathy (a disorder of the optic nerve) that usually occurs in the setting of an elevated intraocular pressure.
• the pressure within the eye increases and this is associated with 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 occurs. High pressure develops in an eye because of an internal fluid imbalance.
• the eye is a hollow structure that contains a clear fluid called "aqueous humor."
• Aqueous humor is formed in the posterior chamber of the eye by the ciliary body at a rate of about 2.5 microliters per minute.
• the fluid which is made at a fairly constant rate, then 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 fluid drains out of the eye through two different routes.
• the fluid percolates between muscle fibers of the ciliary body. This route accounts for approximately ten percent of the aqueous outflow in humans.
• the primary pathway for aqueous outflow in humans is through the "canalicular" route that involves the trabecular meshwork and Schlemm's canal.
• the trabecular meshwork and Schlemm's canal are located at the junction between the iris and the sclera. This junction or corner is called "the angle.”
• the trabecular meshwork is a wedge-shaped structure that runs around the circumference of the eye. It is composed of collagen beams arranged in a three-dimensional sieve-like structure. The beams are lined with a monolayer of cells called trabecular cells. The spaces between the collagen beams are filled with an extracellular substance that is produced by the trabecular cells. These cells also produce enzymes that degrade the extracellular material.
• Schlemm's canal is adjacent to the trabecular meshwork. The outer wall of the trabecular meshwork coincides with the inner wall of Schlemm's canal. Schlemm's canal is a tube-like structure that runs around the circumference of the cornea. In human adults, Schlemm's Canal is believed to be divided by septa into a series of autonomous, dead-end canals.
• aqueous fluid travels through the spaces between the trabecular beams, across the inner wall of Schlemm's canal into the canal, through a series of about 25 collecting channels that drain from Schlemm's canal and into the episcleral venous system, h a normal situation, aqueous production is equal to aqueous outflow and intraocular pressure remains fairly constant in the 15 to 21 mmHg range, h glaucoma, the resistance through the canalicular outflow system is abnormally high.
• the aqueous fluid builds up because it cannot exit fast enough.
• the intraocular pressure (IOP) within the eye increases.
• the increased IOP compresses the axons in the optic nerve and also may compromise the vascular supply to the optic nerve.
• the optic nerve carries vision from the eye to the brain.
• Some optic nerves seem more susceptible to IOP than other eyes. While research is investigating ways to protect the nerve from an elevated pressure, the only therapeutic approach currently available in glaucoma is to reduce the intraocular pressure.
• Medication often is the first treatment option. Administered either topically or orally, these medications work to either reduce aqueous production or they act to increase outflow.
• Currently available medications have many serious side effects including: congestive heart failure, respiratory distress, hypertension, depression, renal stones, aplastic anemia, sexual dysfunction and death. Compliance with medication is a major problem, with estimates that over half of glaucoma patients do not follow their correct dosing schedules.
• laser trabeculoplasty When medication fails to adequately reduce the pressure, laser trabeculoplasty often is performed.
• thermal energy from a laser is applied to a number of noncontiguous spots in the trabecular meshwork. It is believed that the laser energy stimulates the metabolism of the trabecular cells in some way, and changes the extracellular material in the trabecular meshwork.
• aqueous outflow In approximately eighty percent of patients, aqueous outflow is enhanced and IOP decreases. However, the effect often is not long lasting and fifty percent of patients develop an elevated pressure within five years. The laser surgery is not usually repeatable.
• laser trabeculoplasty is not an effective treatment for primary open angle glaucoma in patients less than fifty years of age, nor is it effective for angle closure glaucoma and many secondary glaucomas. If laser trabeculoplasty does not reduce the pressure enough, then filtering surgery is performed. With filtering surgery, a hole is made in the sclera and angle region. This hole allows the aqueous fluid to leave the eye through an alternate route.
• a posterior incision is made in the conjunctiva, the transparent tissue that covers the sclera.
• the conjunctiva is rolled forward, exposing the sclera at the limbus.
• a partial thickness scleral flap is made and dissected half-thickness into the cornea.
• the anterior chamber is entered beneath the scleral flap and a section of deep sclera and trabecular meshwork is excised.
• the scleral flap is loosely sewn back into place.
• the conjunctival incision is tightly closed.
• the aqueous fluid passes through the hole, beneath the scleral flap and collects in an elevated space beneath the conjunctiva. The fluid then is either absorbed through blood vessels in the conjunctiva or traverses across the conjunctiva into the tear film.
• Trabeculectomy is associated with many problems. Fibroblasts that are present in the episclera proliferate and migrate and can scar down the scleral flap. Failure from scarring may occur, particularly in children and young adults. Of eyes that have an initially successful trabeculectomy, eighty percent will fail from scarring within three to five years after surgery. To minimize fibrosis, surgeons now are applying antifibrotic agents such as mitomycin C (MMC) and 5-fluorouracil (5-FU) to the scleral flap at the time of surgery. The use of these agents has increased the success rate of trabeculectomy but also has increased the prevalence of hypotony. Hypotony is a problem that develops when aqueous flows out of the eye too fast. The eye pressure drops too low (usually less than 6.0 mmHg); the structure of the eye collapses and vision decreases.
• MMC mitomycin C
• 5-FU 5-fluorouracil
• Trabeculectomy creates a pathway for aqueous fluid to escape to the surface of the eye. At the same time, it creates a pathway for bacteria that normally live on the surface of the eye and eyelids to get into the eye. If this happens, an internal eye infection can occur called endophthalmitis. Endophthalmitis often leads to permanent and profound visual loss. Endophthalmitis can occur anytime after trabeculectomy. The risk increases with the thin blebs that develop after MMC and 5-FU. Another factor that contributes to infection is the placement of a bleb. Eyes that have trabeculectomy performed inferiorly have about five times the risk of eye infection than eyes that have a superior bleb. Therefore, initial trabeculectomy is performed superiorly under the eyelid, in either the nasal or temporal quadrant.
• trabeculectomy hi addition to scarring, hypotony and infection, there are other complications of trabeculectomy.
• the bleb can tear and lead to profound hypotony.
• the bleb can be irritating and can disrupt the normal tear film, leading to blurred vision.
• Patients with blebs generally cannot wear contact lenses. All of the complications from trabeculectomy stem from the fact that fluid is being diverted from inside the eye to the external surface of the eye.
• An aqueous diversion device of the prior art is a silicone tube that is attached at one end to a plastic (polypropylene or other synthetic) plate.
• an aqueous shunt device With an aqueous shunt device, an incision is made in the conjunctiva, exposing the sclera.
• the plastic plate is sewn to the surface of the eye posteriorly, usually over the equator.
• a full thickness hole is made into the eye at the limbus, usually with a needle.
• the tube is inserted into the eye through this hole.
• the external portion of the tube is covered with either donor sclera or pericardium. The conjunctiva is replaced and the incision is closed tightly.
• aqueous diversion devices With prior art aqueous diversion devices, aqueous drains out of the eye through the silicone tube to the surface of the eye. Deeper orbital tissues then absorb the fluid. The outside end of the tube is protected from fibroblasts and scarring by the plastic plate. Many complications are associated with aqueous shunt devices. A thickened wall of scar tissue that develops around the plastic plate offers some resistance to outflow and in many eyes limits the reduction in eye pressure, hi some eyes, hypotony develops because the flow through the tube is not restricted. Many physicians tie an absorbable suture around the tube and wait for the suture to dissolve post-operatively at which time enough scar tissue has hopefully formed around the plate. Some devices contain a pressure-sensitive valve within the tube, although these valves may not function properly. The surgery involves operating in the posterior orbit and many patients develop an eye muscle imbalance and double vision post-operatively. With prior art aqueous shunt devices, a pathway is created for bacteria to get into the eye and endophthalmitis can potentially occur.
• the prior art includes a number of such aqueous shunt devices, such as
• U.S. Patent No. 4,936,825 providing a tubular shunt from the anterior chamber to the corneal surface for the treatment of glaucoma
• U.S. Patent No. 5,127,901 directed to a transscleral shunt from the anterior chamber to the subconjunctival space
• U.S. Patent No. 5,180,362 teaching a helical steel implant that is placed to provide drainage from the anterior chamber to the subconjunctival space
• U.S. Patent No. 5,433,701 generally teaching shunting from the anterior chamber to the scleral or conjunctival spaces).
• U.S. Patent No. 5,360,399 teaches the temporary placement of a plastic or steel tube with preformed curvature in Schlemm's canal with injection of a viscous material through the tube to hydraulically expand and hydrodissect the trabecular meshwork. The tube is removed from the canal following injection. Because the tube is directed outwardly from the eye for injection access, the intersection of the outflow element with the preformed curved element within Schlemm's canal is at about a 90 degree angle relative to the plane of the curvature, and 180 degrees away from the anterior chamber.
• this tube has a larger diameter injection cuff element, which serves as an adapter for irrigation. Therefore, this device is not adapted for shunting aqueous between the anterior chamber and Schlemm's canal.
• Enhancing aqueous flow directly into Schlemm's canal would minimize hypotony since the canal is part of the normal outflow system and is biologically engineered to handle the normal volume of aqueous humor. Enhancing aqueous flow directly into Schlemm's canal would eliminate complications such as endophthalmitis and leaks.
• the present invention is directed to a novel shunt and an associated surgical method for the treatment of glaucoma in which the shunt is placed to divert aqueous humor from the anterior chamber of the eye into Schlemm's canal.
• the present invention therefore facilitates the normal physiologic pathway for drainage of aqueous humor from the anterior chamber, rather than shunting to the sclera or another anatomic site as is done in most prior art shunt devices.
• the present invention is further directed to providing a permanent, indwelling shunt to provide increased egress of aqueous humor from the anterior chamber to Schlemm's canal for glaucoma management.
• FIG. 1 A is an illustration showing an overhead perspective view of one embodiment of the present invention, in which the inventive shunt is comprised of tubular elements extending bi-directionally within Schlemm's canal.
• FIG. IB is an overhead view of the embodiment of the present invention shown in FIG. 1A, with phantom lines detailing the internal communication between the lumens of the tubular elements comprising the inventive device.
• FIG. 1C is an illustration showing an overhead perspective view of one embodiment of the present invention, in which the inventive shunt is comprised of mesh tubular elements extending bi-directionally within Schlemm's canal.
• FIG. ID is an illustration showing an overhead perspective view of one embodiment of the present invention, in which the inventive shunt is comprised of solid, porous elements extending bi-directionally within Schlemm's canal.
• FIG. IE is an overhead perspective view of another embodiment of the present invention, with phantom lines detailing the internal communication between the two proximal lumens and the single distal lumen of the inventive device.
• FIG. 2 is an illustration showing another embodiment of the present invention, in which the inventive shunt is comprised of perforated tubular elements and with an angulated terminal aspect of the proximal portion.
• FIG. 3A is an illustration showing a perspective of another embodiment of the present invention in which the inventive shunt is comprised of elements that are partially tubular and partially open in their configuration.
• FIG. 3B is an illustration showing a top view of the embodiment of the present invention in FIG. 3A, with phantom lines detailing the internal communication of the device.
• FIG. 3C is an illustration showing a side view from the proximal end of the embodiment of the present invention in FIG. 3 A.
• FIG. 3D is an illustration showing a perspective of another embodiment of the present invention in which the inventive shunt is comprised of elements that are partially open and trough-like in their configuration.
• FIG. 4 is an illustration showing another embodiment of the present invention, in which the inventive shunt is comprised of distal elements having wicking extensions at their terminal ends, and in which the proximal portion has a sealed, blunted tip with a portal continuous with the lumen of the proximal portion, oriented to face away from the iris when the device is implanted in Schlemm's canal.
• FIG. 5A is an illustration showing another embodiment of the inventive shunt in which a portion of the device enters Schlemm's canal in only one direction and shunts fluid in a non-linear path from the anterior chamber.
• FIG. 5B is an illustration showing an alternative embodiment of the inventive shunt in which the entire shunt is placed within Schlemm's canal but contains a fenestration to maintain fluid egress of aqueous humor from the anterior chamber to Schlemm's canal.
• FIG. 5C is an illustration showing a side view of one embodiment of the present invention, in which the inventive shunt is comprised of tubular elements, with a proximal portion extending towards the anterior chamber that is shorter relative to the distal portions which extend bi-directionally within Schlemm's canal.
• FIG. 5D is an illustration showing an alternative embodiment of the inventive shunt comprised of a partially open trough-like element which is placed within Schlemm's canal but contains a portal to maintain fluid egress of aqueous humor from the anterior chamber to Schlemm's canal.
• FIG. 5E is an illustration showing an alternative embodiment of the inventive shunt comprised of a solid, but porous wick-like element which is placed within Schlemm's canal
• FIG. 6A is an illustration showing certain anatomic details of the human eye.
• FIG. 6B is a cross-sectional illustration showing the anatomic relationships of the surgical placement of an exemplary embodiment of the present invention.
• FIG. 6C is a cross-sectional illustration showing the anatomic relationships of the surgical placement of another exemplary embodiment of the present invention in which the proximal portion has an angulated terminal aspect with a sealed, blunted tip with a portal continuous with the lumen of the proximal portion, oriented to face away from the iris when the device is implanted in Schlemm's canal.
• FIG. 7A is a cross-sectional illustration showing the anatomic relationships of the surgical placement of an exemplary embodiment of the present invention showing the proximal portion of the device and a barb-shaped anchor extending toward the iris.
• FIG. 7B is a cross-sectional illustration showing the anatomic relationships of the surgical placement of another exemplary embodiment of the present invention showing the proximal portion of the device having an annular or circumferential anchor thereon.
• FIG. 8A shows one embodiment of the device having a bi-directional distal portion and an anchor on the proximal portion extending circumferentially thereon.
• FIG. 8B shows another embodiment of the device having a bidirectional distal portion and an anchor on the proximal portion extending medially toward the location of the iris when implanted.
• FIG. 8C shows another embodiment of the device having a bidirectional distal portion and an anchor on the proximal portion extending laterally on each side of the device when implanted.
• FIG. 9 shows another embodiment having a bi-directional distal portion and an anchor on the proximal portion extending circumferentially thereon in a barbed or cone shape to facilitate introduction into the anterior chamber and to inhibit removal therefrom.
• FIG. 10 shows another embodiment having a tapered proximal portion with screw threads.
• the present invention provides an aqueous humor shunt device to divert aqueous humor in the eye from the anterior chamber into Schlemm's canal, in which the shunt device comprises a distal portion having at least one terminal aspect sized and shaped to be circumferentially received within a portion of Schlemm's canal, and a proximal portion having at least one terminal aspect sized and shaped to be received within the anterior chamber of the eye, wherein the device permits fluid communication between the proximal portion in the anterior chamber to the distal portion in Schlemm's canal. Fluid communication can be facilitated by an aqueous humor directing channel in either the proximal or distal portions, as described below. Fluid communication can also be facilitated by a wicking function of a solid proximal or distal portions of the device, for example.
• the present invention also provides embodiments of an inventive shunt comprising a body of biocompatible material of a size and shape adapted to be at least partially circumferentially received within a portion of Schlemm's canal to divert aqueous humor from the anterior chamber of the human eye to and within Schlemm's canal, and wherein the body facilitates the passage of aqueous humor from the anterior chamber into Schlemm's canal.
• This embodiment of the device of the present invention can be produced without the proximal portion of the previous embodiment extending into the anterior chamber.
• An aqueous humor directing channel can facilitate the passage of aqueous humor from the anterior chamber into Schlemm's canal. Fluid commumcation can also be facilitated by a wicking function of a solid body portion, for example.
• the invention contemplates many different configurations for an aqueous humor directing channel, provided that each assists in channeling aqueous humor from the anterior chamber to Schlemm's canal, such as by providing a lumen, trough, wick or capillary action.
• the aqueous humor directing channel can be a fully enclosed lumen, a partially enclosed lumen, or a trough-like channel that is at least partially open.
• a solid monofilament or braided polymer such as Proline® (polypropylene)
• Proline® polypropylene
• Such a wicking or stenting extension can also be grooved or fluted along any portion of the length thereof, so as to be multi-angular or star-shaped in cross-section.
• the devices of the present invention can be constructed of a solid, matrix, mesh, fenestrated, or porous material, or combinations thereof.
• Schlemm's canal in an adult is divided by septa into separate canals, rendering the complete passage of a suture impossible.
• Preliminary studies on adult human eye bank eyes have shown that Schlemm's canal is, indeed, patent.
• a suture can be passed through the entire circumference of the canal. It has not been heretofore determined that Schlemm's canal is patent throughout its circumference in normal adult individuals, as opposed to being divided by septae into multiple dead end canals.
• the invention utilizes this knowledge to access Schlemm's canal and to create and maintain the natural physiologic egress of aqueous humor from the anterior chamber to Schlemm's canal and to the collecting channels.
• the present invention also provides methods of use of the shunt devices.
• One embodiment of the present invention is directed to a surgical method to divert aqueous humor from the anterior chamber of the eye into Schlemm's canal with a device that is implanted to extend from within the anterior chamber to Schlemm's canal.
• the portion of the device extending into Schlemm's canal can be fashioned from a flexible material, such as silicone, capable of being received within a portion of the radius, curvature, and diameter of Schlemm's canal.
• the external diameter of the proximal portion can be about 0.1 mm to 0.5 mm, or about 0.3 mm.
• FIG. 1 A One embodiment of the present invention is illustrated in FIG. 1 A, in which the shunt device 100 is shown in a side view.
• the shunt device 100 of this embodiment is comprised of two portions, a proximal portion 10 which joins a distal portion 25.
• the proximal portion 10 and distal portion 25 shown create an enclosed tubular channeling structure.
• the total length of the distal portion 25 may be between about 1.0 mm to 40 mm, preferably about 4 mm to 6 mm.
• the same embodiment of the present invention is illustrated with phantom lines showing the internal fluid communication path in FIG. IB.
• the lumen or channeling space defined by the walls of the proximal portion 10 and the distal portion(s) 25 are continuous at their junction at the distal portion portal 20.
• FIG. 1C An alternate embodiment of the present invention is shown in FIG. 1C, in which the shunt device 100 is comprised of two luminal mesh elements, with a proximal portion 10 which joins a distal portion 25.
• FIG. ID Yet another embodiment of the present invention is shown in FIG. ID, in which the shunt device 100 is comprised of two solid, porous elements which may provide wick-like fluid communication therethrough, with a proximal portion 10 which joins a distal portion 25.
• FIG. IE An alternate embodiment of the present invention is shown in FIG. IE, in which the shunt device 100 is comprised of a proximal portion 10 having two lumens therein terminating in proximal portion portals 18.
• the distal portion 25 shaped and sized to be received within Schlemm's canal extends in either direction having separate lumens traversing therethrough from each of the distal portion portals 20.
• FIG. 2 shows an embodiment of the inventive shunt in which the device 100 is tubular and fenestrated (15, 30) in its configuration, with an acute ( ⁇ 90 ) angle of junction between the proximal portion 10 and the plane defined by the distal portion 25.
• Such fenestrations (15, 30) may be placed along any portion of the device 100 to facilitate the passage of fluid therethrough, but are particularly directed towards the collecting channels of the eye.
• FIG. 2 further shows an alternate embodiment of the present invention in which the terminal aspect 16 of the proximal portion is angulated toward the iris 40 with respect to the main axis of the proximal portion 10, with the portal 18 of the proximal portion directed toward from the iris 40. h alternate embodiments as shown in FIG. 6C, the portal 18 of the proximal portion 16 is directed away from the iris 40.
• FIG. 3A shows an embodiment of the inventive shunt in which a portion of the channeling device is enclosed and tubular in configuration at the junction of the proximal portion 10 and the distal portion 25, but where the distal portion 10 is a trough-like channel.
• the distal portion portal 20 is also shown.
• the invention contemplates that any portion of the device 100 can be semi-tubular, open and trough-like, or a wick-like extension.
• Tubular channels can be round, ovoid, or any other enclosed geometry.
• the non-tubular trough-like aspects are oriented posteriorly on the outer wall of the canal to facilitate aqueous humor drainage to the collecting channels of the eye, as shown in FIG. 3 A.
• FIG. 3B shows an overhead view of the embodiment of the inventive shunt of FIG. 3 A, further detailing the relationship among the proximal portion 10 and the distal portion 25.
• the aqueous humor directing channel is shown in dashed lines.
• FIG. 3C shows a proximal view of the embodiment of the inventive shunt of FIG. 3 A, further detailing the relationship among the proximal portion 10 and the distal portion 25.
• FIG. 3D shows another embodiment of the inventive shunt in which the structure of the device 100 comprises an aqueous humor directing channel that is both open and curved in a continuous trough-like configuration along the proximal portion 10 and the distal portion 25.
• the distal portion portal 20 is also an open trough-like channel.
• FIG. 4 shows another embodiment of the inventive shunt with the addition of aqueous humor-wicking extensions 32 which are either continuous with, or attached to the terminal aspects of the distal portion 25.
• the wicking extensions 32 can be fashioned from a monofilament or braided polymer, such as proline, and preferably have a length of about 1.0 mm to about 16.0 mm.
• the proximal portion 10 is curved with a sealed, blunted tip 16 and contains a portal 18 in fluid communication with the lumen of the proximal portion and oriented to face away from the iris when the shunt device 100 is implanted in its intended anatomic position.
• the shunt device 100 can also help to maintain the patency of Schlemm's canal in a stenting fashion.
• FIG. 5 A shows another embodiment of the inventive shunt in which the proximal portion 10 joins a single, curved distal portion 25 in a "V-shaped," tubular configuration.
• the embodiment shown in FIG. 5A can also have a portal (not shown) in the distal portion 25 adjacent to the junction with the proximal portion 10 in order to facilitate bi-directional flow of fluid within the canal.
• Fenestrations and non-tubular, trough-like terminal openings are contemplated in all embodiments of the invention, and these fenestrations and openings may be round, ovoid, or other shapes as needed for optimum aqueous humor channeling function within the anatomic spaces involved.
• FIG. 5B shows another embodiment of the inventive shunt in which the body or device 100 comprises only a single, curved distal portion 25 which contains a distal portion portal 20 oriented towards the anterior chamber to allow egress of aqueous humor from the anterior chamber to Schlemm's canal.
• the body of this device can have a length of about 1.0 mm to about 40 mm, preferably about 6 mm.
• the external diameter of the device (or the distal portions of the device) can be about 0.1 mm to about 0.5 mm, preferably about 0.2 mm to about 0.3 mm, preferably about 0.23 mm to about 0.28 mm or about 0.26 mm.
• FIG. 5C shows another embodiment of the inventive shunt in which the device 100 comprises a bi-directional tubular distal portion 25 which is intersected by a proximal portion 10 which is short in length relative to the distal portion 25 and is directed towards the anterior chamber.
• FIG. 5D shows still another embodiment of the inventive shunt in which the device 100 comprises a bi-directional, trough-like, curved distal portion 25 for insertion into Schlemm's canal, which contains a distal portion portal 20 oriented to allow egress of aqueous humor from the anterior chamber, wherein the trough-like distal portion 25 is oriented to open toward the collecting channels to facilitate the egress of aqueous humor.
• FIG. 5E shows another embodiment of the inventive shunt in which the device 100 comprises a bi-directional, solid distal portion 25 for insertion into Schlemm's canal to facilitate the egress of aqueous humor from the canal to the collecting channels in a wicking capacity.
• the solid distal portion 25 can be porous or non-porous.
• the inventive device is an implant, it can be fabricated from a material that will be compatible with the tissues and fluids with which it is in contact.
• the device may be constructed of biodegradable or non-biodegradable materials. It is preferable that the device not be absorbed, corroded, or otherwise structurally compromised during its in situ tenure. Moreover, it is equally important that the eye tissues and the aqueous remain non-detrimentally affected by the presence of the implanted device. A number of materials are available to meet the engineering and medical specifications for the shunts.
• the shunt device 100 is constructed of a biologically inert, flexible material such as silicone or similar polymers.
• the shunt device 100 may be constructed as either porous or solid in alternate embodiments.
• the material can contain a therapeutic agent deliverable to the adjacent tissues.
• the proximal portion 10 joins the distal portion(s) 25 at an angle sufficient to allow the placement of the proximal portion 15 within the anterior chamber of the eye when the distal portion 25 is oriented in the plane of Schlemm's canal.
• the proximal portion 10 is preferably of sufficient length, about 0.1 to about 3.0 mm or about 2.0 mm, to extend from its junction with the distal portion 25 in Schlemm's canal towards the adjacent space of the anterior chamber.
• the diameter or width of the proximal portion 10 can be sized to yield an internal diameter of between about 0.1 and about 0.5 mm, preferably about 0.2 mm to about 0.3 mm for a tubular or curved shunt, or a comparable maximal width for a shunt with a multiangular configuration.
• the proximal portion is a non- luminal, non-trough-like wicking extension that provides an aqueous humor directing channel along the length thereof.
• the proximal portion 10 may contain a plurality of fenestrations to allow fluid ingress, arranged to prevent occlusion by the adjacent iris.
• the proximal portion 10 may comprise only a proximal portion portal 18 in the form of a fenestration oriented anteriorly to provide continuous fluid egress between the anterior chamber of the eye and the directing channel of the shunt.
• Said fenestrations may be any functional size, and circular or non-circular in various embodiments of the present invention.
• a porous structural material can assist in channeling aqueous humor, while minimizing the potential for intake of fimbriae.
• the proximal portion 10 may be positioned sufficiently remote from the iris 40 to prevent interference therewith, such as by traversing a more anterior aspect of the trabecular meshwork into the peripheral corneal tissue, h yet another possible embodiment, as shown in FIG. 6C, the device 100 may comprise a proximal portion 10 in which the terminal aspect of said proximal portion 10 is curved or angled toward the iris 40, and with a blunted, sealed tip 16 and a portal 18 oriented anteriorly to face away from the underlying iris 40. Such a configuration would tend to decrease the possibility of occlusion of the shunt device by the iris 40.
• the device 100 may contain one or more unidirectional valves to prevent backflow into the anterior chamber from Schlemm's canal.
• the internal lumen for an enclosed portion of the device or the internal channel defined by the edges of an open portion of the device communicates directly with the inner lumen or channel of the distal portion at the proximal portion portal 20.
• the distal portion 25 may have a pre-formed curve to approximate the
• the distal portion 25 may be of sufficient length to extend from the junction with the proximal portion 10 through any length of the entire circumference of Schlemm's canal.
• Embodiments having a distal portion 25 that extends in either direction within Schlemm's canal can extend in each direction about 1.0 mm to 20 mm, or about 3.0 mm. to permit circumferential placement through Schlemm's canal.
• the diameter or width of the distal portion 25 can be sized to yield an outer diameter of between about 0.1 and 0.5 mm, or about 0.3 mm, for a tubular or curved shunt, or a comparable maximal width for a shunt with a multiangular configuration.
• the distal portion 25 may contain a plurality of fenestrations to allow fluid egress, arranged to prevent occlusion by the adjacent walls of Schlemm's canal.
• the distal portion is a non-luminal, non-trough-like wicking extension that provides an aqueous humor directing channel along the length thereof.
• the shunt device may be either bi-directional, with the distal portion of the implant intersecting with the proximal portion in a "T-shaped" junction as shown in FIGS. 1A-1E, 2, 3A- 3D, 4 and 5C, or uni-directional, with a "V-shaped" junction of the proximal and distal shunt portions, as shown in FIG. 5A.
• a bi-directional shunt device can have a distal portion that is threaded into opposing directions within Schlemm's canal.
• non-linear fluid communication means that at least some portion of the shunt through which fluid passes is not in a straight line.
• non-linear shunts are the above described bi-directional "T” shapes, and the uni-directional "V shapes, or shunts having two channel openings which are not in straight alignment with each other when implanted.
• FIG. 6A Generally, FIG. 6A shows the anterior chamber 35, Schlemm's canal 30, the iris 40, cornea 45, trabecular meshwork 50, collecting channels 55, episcleral veins 60, pupil 65, and lens 70.
• FIG. 6B illustrates the surgical placement of the exemplary embodiment of the present invention, with the relevant anatomic relationships. It should be noted that the inventive device is designed so that placement of the distal portion 25 within Schlemm's canal 30 results in an orientation of the proximal portion 10 within the anterior chamber 35 within the angle defined by the iris 40 and the inner surface of the cornea 45.
• the proximal portion 10 can extend therefrom at an angle of between about +60 degrees towards the cornea 45 or -30 degrees toward the iris 40, more preferably in the range of 0 to +45 degrees. This range may vary in individuals having a slightly different location of Schlemm's canal 30 relative to the limbal angle of the anterior chamber 35.
• the shunt device 100 is configured with one distal portion 25 which is tubular to provide a shunting functionality and a plurality of proximal portions 10 which provide an anchoring function to stabilize the overall implant device, in addition to providing fluid communication from the anterior chamber to Schlemm's Canal.
• the invention provides an aqueous humor shunt device to divert aqueous humor in an eye from the anterior chamber into Schlemm's canal, the shunt device comprising a distal portion having at least one terminal aspect sized and shaped to be received circumferentially within a portion of Schlemm's canal and a proximal portion having at least one terminal aspect sized and shaped to be received within the anterior chamber of the eye, wherein the proximal portion has an anchor extending therefrom to maintain the position of the terminal aspect of the proximal portion within the anterior chamber of the eye, wherein device permits fluid communication from the proximal portion in the anterior chamber to the distal portion in Schlemm's canal.
• such an anchor can extend from distal portions of the device to assist in stabilization of the implant within Schlemm's canal.
• the multiple proximal portions or the anchor extension(s) from the distal or proximal portion provide multiple improvements for the shunt device.
• the anchor facilitates implantation and proper placement of the device, as the proximal portion can be advanced into the anterior chamber and then pulled back into place until it contacts the edge of the anterior chamber.
• a shelf may be created by the surgical procedure for implantation that is designed to capture the anchor. This permits the surgeon to determine how much of the proximal portion is left extending into the anterior chamber.
• the anchor feature also allows the surgical alternative of first implanting the proximal portion into the anterior chamber, and then placing the distal portion(s) into Schlemm's canal.
• the anchor also serves to anchor the shunt device in the desired location within the anterior chamber and Schlemm's canal with minimal shifting during normal use.
• the anchor can be fabricated by a simple thickening of the material of construction of the shunt, e.g. silicon, at the desired site on the proximal portion, or can be made of another material attached thereto. Additionally, the anchor can be fabricated by removal of excess material.
• the anchor can extend from the proximal portion in virtually any functional shape, such as in a rounded or barbed fashion.
• FIG. 7A is a cross-sectional illustration showing the anatomic relationships of the surgical placement of an exemplary embodiment of the present invention showing the proximal portion 10 of the device and a barb-shaped anchor 80 extending toward the iris.
• FIG. 7B is a cross-sectional illustration showing the anatomic relationships of the surgical placement of another exemplary embodiment of the present invention showing the proximal portion 10 of the device having an annular or circumferential anchor 80 thereon.
• the anchor can extend circumferentially around the proximal portion, or only in one or more directions therefrom.
• FIG. 8A shows one embodiment of the device having a bi-directional distal portion 25 and an anchor 80 on the proximal portion 10 extending circumferentially thereon.
• FIG. 8B shows another embodiment of the device having a bi-directional distal portion 25 and an anchor 80 on the proximal portion 10 extending medially toward the location of the iris when implanted.
• FIG. 8C shows another embodiment of the device having a bi-directional distal portion 25 and an anchor 80 on the proximal portion 10 extending laterally on each side of the device when implanted.
• the invention contemplates many other configurations of the anchor, including a plurality of teeth extending from the proximal portion.
• the device may also be provided with an anchor for placement adjacent the exterior surface of the anterior chamber to assist in surgical placement and securing the device, with or without a corresponding anchor adjacent the interior surface of the anterior chamber.
• an anchor for placement adjacent the exterior surface of the anterior chamber to assist in surgical placement and securing the device, with or without a corresponding anchor adjacent the interior surface of the anterior chamber.
• a potential configuration to stabilize the implant is a device having anchors for positioning inside the anterior chamber and inside Schlemm's canal to secure the device about the trabecular meshwork between the anterior chamber and Schlemm's canal.
• the anchor can extend in any direction in any shape and size which facilitates implantation or anchoring of the device.
• FIG. 9 shows another embodiment having a bi-directional distal portion 25 and an anchor 80 on the proximal portion 10 extending circumferentially thereon in a barbed or cone shape to facilitate introduction into the anterior chamber and to inhibit removal therefrom.
• the end of the proximal portion can be cut at an angle, rather than blunted or square cut, in order to facilitate introduction through the wall of the anterior chamber.
• the angled shape of the tip of the proximal portion allows the proximal portal to have a larger surface area to facilitate the flow of aqueous.
• the device should be at least capable of permitting the flow of aqueous humor at the estimated normal production rate of about 2.5 microliters per minute.
• Figure 10 shows yet another embodiment of the device in which the proximal end comprises a larger single proximal lumen 10 which branches to form a pair of distal lumens 25 for insertion into Schlemm's canal.
• the proximal end is preferably tapered and contains screw threads 80 such that the device can be screwed into the anterior chamber and anchored therein by means of the threads and the distal ends inserted in Schlemm's canal.
• This embodiment would, in some instances, simplify insertion by eliminating the need to make an incision into the anterior chamber.
• the anchor as well as optionally the remainder of the device, can be constructed on a textured, grooved or porous material in order to facilitate the growth of cells, such as fibroblasts, to stabilize the implant from movement.
• the extreme tips of the proximal and distal ends of the device are produced to avoid the attraction of new tissues, such as fibroblasts, which may grow at the surgical site and impede the flow of aqueous therethrough. Therefore, the proximal portion of the device can be produced to extend beyond the entrance into the anterior chamber by 0.1 to 3 mm, or preferably about 0.5 mm.
• the angled tip of the proximal portal will create a range of lengths along the proximal portion extending into the anterior chamber.
• the distal portion(s) should similarly extend beyond the site of surgery and subsequent fibroblast proliferation. Therefore, the distal portion(s) can have a length of approximately 4 mm to 6 mm, again taking into consideration variability for angled extremities.
• the single or dual lumen shunt devices of the present invention can be manufactured by conventional molding or extrusion techniques. In the case of extrusion production, single lumens can be subsequently partially joined together to form dual lumen devices, or the individual lumens of a co-extruded dual lumen devices can be partially separated to define distal portions extendable in separate directions. It is preferable that such devices be constructed such that they will not kink when wrapped around a 0.25mm object.
• the device may also include one or more visible markings on the device to assist in proper placement in the anterior chamber or Schlemm's canal. Markings on the distal ends could be used to confirm the distal ends are properly inserted in Schlemm's canal and markings on the proximal end would avoid over or under insertion into the anterior chamber.
• the device may be selectively coated or permeated with therapeutic agents as desired.
• therapeutic agents such as 5- fluourouracil or mitomycin.
• the device may be more generally provided with coatings that are antibiotic, anti-inflammatory, or carboxylic anhydrase inhibitors. Agents that facilitate the degradation of collagen within the trabecular meshwork can also be employed.
• the present invention provides methods for the implantation and use of the shunt devices.
• the surgical procedure necessary to insert the device requires an approach through a conjunctival flap.
• a partial thickness scleral flap is then created and dissected half-thickness into clear cornea.
• the posterior aspect of Schlemm's canal is identified and the canal is entered posteriorly.
• Schlemm's canal and/or the anterior chamber may be expanded and lubricated by injection of a viscoelastic and/or a mitotic agent. Suitable viscoelastic compositions and devices and methods for their injection into the eye are disclosed in United States Patent 5,360,399 which is incorporated herein by reference.
• One arm of the distal portion of the shunt device is grasped and threaded into Schlemm's canal, h a similar fashion, the other arm of the distal portion of the shunt device (when present) is inserted into Schlemm's canal in the opposing direction from the first.
• the scleral flap and conjunctival wound are closed in a conventional manner.
• anesthetic agent lidocaine, bupivacaine, etc.
• a viscocanalostomy cannula and a viscoelastic agent (e.g., hyaluronate or hyaluronate/chondroitin sulfate).
• a viscoelastic agent e.g., hyaluronate or hyaluronate/chondroitin sulfate.
• a study in 16 swine was performed using a shunt device comprising two (2) 7 mm length, 0.125mm inner diameter and 0.250mm outer diameter silicone (65 A durometer) tubes bonded together with silicone adhesive over a 1.0 mm length at the proximal end, creating a Y shape.
• the device was implanted in one eye of each animal and the non-implanted eye served as a control.
• a second, deeper flap was created at the base of the first flap, and dissected anteriorly to unroof the porcine equivalent of Schlemm's canal.
• the plane of the deeper flap then was angled anteriorly to create a corneoscleral shelf.
• a viscoelastic agent (hyaluronate and chondroitin sulfate) was instilled into the Schlemm's canal-like space on either side using a viscocanalostomy cannula.
• the distal aspects of the bi-directional glaucoma shunt were inserted into the canal on either side of the unroofing site.
• the anterior chamber was entered through the corneoscleral shelf and a viscoelastic agent instilled into the anterior chamber.
• the proximal (radial) portion of the shunt was inserted into the anterior chamber through the corneoscleral shelf.
• the scleral flaps were tightly closed with 10-0 nylon sutures and the knots buried.
• the conjunctiva was closed with absorbable suture.
• the bridle suture was removed.
• Subconjuctival garamycin and decadron were instilled interiorly.
• the eye was dressed with tobramycin-decadron ointment. The animal was allowed to awaken and returned to the boarding area.

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