Shunts and methods for treating glaucoma - Patents.com

Abstract

A shunt 10 for treating glaucoma comprises a silicone rubber duct 12 for diverting aqueous humor from the chamber of a patient's eye, and a fixation body 16 frictionally positioned in the duct 12 in a slidably displaceable arrangement for fixing and sealing the duct in the scleral tissue surrounding the eye. The duct has a rigid proximal portion 24 having a proximal end 20 and a deformable distal portion 22 positionable in the scleral channel and having a distal end 18.1. The distal portion is severable, allowing the physician to cut the distal portion to a desired length corresponding to the anatomical dimensions of the patient's eye and the required bleb location. The proximal portion 24 has a capillary lumen 28 with a diameter smaller than the diameter of the lumen 26 of the distal portion, thereby reducing the flow rate of aqueous humor along the capillary lumen.

Description

[Technical field]

[0001] The present invention relates to a shunt for treating glaucoma in a patient. The present invention also relates to a method for treating glaucoma in a patient. More particularly, the present invention relates to a shunt and method for treating glaucoma in a patient by diverting aqueous humor from the ocular chamber to the subconjunctival space of the patient. [Background technology]

[0002] Glaucoma is an eye disease characterized by the presence of high intraocular pressure (IOP), which causes irreversible damage to the optic nerve. The globe of the eye has a tough outer layer consisting of the sclera and cornea. The interior region of the eye is divided into the anterior and posterior segments. The anterior segment includes the anterior and posterior chambers, which are filled with aqueous humor, while the posterior segment includes the vitreous cavity, which is filled with vitreous gel. The cornea joins with the sclera at a junction called the limbus. A portion of the sclera is covered by a thin tissue called Tenon's membrane (also called Tenon's capsule), which encases the eyeball from the optic nerve to the ciliary body region. A portion of Tenon's membrane is covered by another thin membrane of tissue known as the conjunctiva. Near its anterior portion, Tenon's membrane blends into the conjunctiva, where it attaches to the ciliary body region of the eye.

[0003] The eye maintains an internal pressure, known as intraocular pressure, which normally varies between 10 and 21 mmHg. Intraocular pressure needs to be controlled within a defined range for the eye to function normally. Intraocular pressure is regulated by maintaining a balance between the amount of aqueous humor produced and the amount of aqueous humor drained from the anterior segment of the eye. Aqueous humor is produced by the ciliary body at a rate that varies between 2 and 3 micromillimeters per minute. Age is one of the factors that affect the rate of aqueous humor production, with older patients having a significantly lower rate of aqueous humor production than younger patients. Aqueous humor drains from the anterior chamber through the trabecular and uveoscleral pathways at different rates. When there is a dysfunction in the amount of aqueous humor draining from the eye, intraocular pressure becomes too high. The presence of high intraocular pressure increases the pressure difference across the lamina cribrosa (translamina cribrosa pressure). This causes damage to the optic nerve head, known as glaucoma. Glaucoma causes irreversible visual field defects. These defects expand until the patient's visual field is severely constricted. In the final stage of the disease, complete blindness occurs. Glaucoma is the leading cause of blindness worldwide. If the intraocular pressure remains very high, the eye may continue to hurt and may need to be relieved.

[0004] Current medical laser and surgical treatment options for glaucoma aim to lower intraocular pressure. Glaucoma that is difficult to control with primary treatments such as topical medications and laser therapy is known as refractory glaucoma. Refractory glaucoma is often managed with the implantation of glaucoma drainage tubes, which create additional aqueous humor outflow from the anterior chamber into the subconjunctival space. Aqueous humor draining into the subconjunctival space creates a fluid blister between the sclera and conjunctiva, known as a bleb. Over time, the bleb becomes encapsulated by the fibrous vascular wall of Tenon's tissue.

[0005] During the early weeks after implantation, the bleb wall is not well formed and there is minimal resistance to fluid flow into the subconjunctival space. This means that glaucoma drainage devices tend to over-drain in the early stages. Because of the over-drainage in the early stages, the IOP may drop below 5 mmHg. This causes a condition known as ocular hypotony. Hypotension can lead to complications such as maculopathy and choroidal effusion.

[0006] Resistance to flow into the bleb then gradually increases during bleb wall formation in the intermediate period of 4 to 12 weeks after implantation. Thus, it is preferred that the device provide higher resistance to fluid flow after implantation in the early period to prevent hypotony, and lower resistance in the middle to late stages to increase drainage of aqueous humor.

[0007] In general, bleb size is related to the capacity of the bleb to absorb aqueous humor. In later stages after device implantation, bleb size may decrease when inflammation and scarring from unhealthy conjunctiva occurs. If the bleb size decreases sufficiently, poor filtration and recurrence of glaucoma may occur. In the presence of localized areas of unhealthy conjunctiva, the ideal bleb position to avoid poor filtration may vary from patient to patient. The ideal bleb position may be 4 mm proximal to the limbus or 30 mm posterior to the limbus. In cases of globally unhealthy conjunctiva, a sub-Tenon footplate connected to a drainage tube may be required to help maintain the surface area of ​​the bleb and avoid poor filtration.

[0008] The presence of tubes in the anterior chamber is known to be a risk for damaging corneal endothelial cells, which can lead to corneal decompensation, blindness, and ultimately a painful condition known as bullous keratopathy. The diameter, length, stiffness, and location of the tubes in the anterior chamber are all known to contribute to the risk of endothelial cell damage.

[0009] If the tube is not securely attached to the eye, migration of the device may occur, which may cause the tube to become dislodged from inside the anterior chamber or damage the endothelial cells.

[0010] Conventional aqueous humor drainage devices, such as the Barbelt device (US Pat. No. 6,050,970), consist of a continuous diameter silicone tube, approximately 0.6 mm outer diameter and 0.3 mm inner diameter, attached to a large footplate. The footplate is sutured to the sclera 10 mm posterior to the limbus in the subconjunctival space. A needle body is then used to create a scleral channel that extends from the scleral surface to the anterior segment. A silicone tube is inserted through the scleral channel to enter the anterior chamber. The silicone tube is then fully or partially blocked with sutures to restrict fluid flow and adjust pressure.

[0011] Newer aqueous humor drainage devices, such as the Microshunt device (U.S. Pat. No. 9,101,444), consist of a straight tube about 8 mm long with spaced tabs integrated midway between the proximal and distal ends of the tube. The entire length of the device is straight with a microcapillary lumen about 0.07 mm in inner diameter, which is dimensioned to provide resistance to fluid flow and prevent IOP from dropping below 5 mmHg. A scleral channel is created with the needle body to enter the anterior chamber. The distal end of the tube passes through the scleral channel into the anterior chamber. Tabs are disposed in the scleral channel to create a fluid seal between the tube and the surrounding scleral tissue. The proximal end is then left in the subconjunctival space to create a bleb about 6 mm from the limbus.

[0012] Existing glaucoma drainage devices have several drawbacks that can increase the risk of aqueous humor leakage, ocular hypotony, poor filtration, endothelial cell damage, and device migration. These drawbacks include: 1. Drainage devices such as the Barbelt and Microshunt devices create a bleb at a predetermined distance from the limbus, which prevents the physician from creating the bleb at a location of their choice where they believe the risk of scarring and poor filtration is minimal. 2. Drainage devices such as microshunt devices contain capillary valves across the entire length of the drainage device, meaning the device cannot be cut to the required length without significantly changing the resistance to fluid flow. 3. Drainage devices such as the Barbelt and Microshunt devices have straight tubing to pass through the scleral channel to enter the anterior chamber. This means that the direction of the tubing is directed towards the corneal endothelium, risking endothelial cell damage. When entering the anterior or posterior chamber, it is desirable for the tubing to move in a direction parallel to the iris plane. 4. Drainage devices such as the Valvert device do not include built-in flow resistance mechanisms such as leaf or capillary valves. This requires the physician to ligate the tubing with sutures for a period of time until the bleb forms. This makes the procedure more complicated and delays the action of the pressure drop of such devices. 5. Drainage devices such as microshunt devices include locating tabs that have a rounded, symmetrical exterior shape that provides minimal resistance to movement when implanted in the scleral channel, meaning that even a relatively small longitudinal force applied to the tubing can result in unwanted device movement along the scleral channel. 6. Drainage devices such as the Valvert and Microshunt are each supplied with or without a footplate, meaning that the physician does not have a choice as to whether or not they deem a footplate desirable for a particular patient. 7. Drainage devices such as Barbelts and Microshunts provide a constant resistance to fluid flow and therefore cannot be adjusted to an individual patient's aqueous humor production rate or made variable with time after surgery. Summary of the Invention [Problem to be solved by the invention]

[0013] It is an object of the present invention to provide a shunt and method for treating glaucoma that addresses the above-mentioned shortcomings.

[0014] As used herein, the term "distal" means toward the patient's eye or away from the user of the shunt, while the term "proximal" means away from the patient's eye or toward the user of the shunt. [Means for solving the problem]

[0015] According to a first aspect of the present invention there is provided a shunt for treating glaucoma by reducing intraocular pressure in an eye of a patient, comprising: an elongated duct defining a fluid passageway for diverting aqueous humor from the chamber of the eye, the elongated duct having a distal end implantable in the chamber of the eye and an opposite proximal end; A fixed body extending outward from the elongated duct; 1. A shunt comprising: the elongated duct has a distal portion positionable in the patient's scleral channel and defining a distal end of the duct, the distal portion being deformable to allow the distal portion to conform to the patient's ocular anatomy and being of a severable material to allow a physician to cut the distal portion to a desired length corresponding to a desired location for the formation of a bleb through which aqueous humor can be drained; and a proximal portion defining a proximal end of the elongated duct; the distal portion has a distal lumen defining a distal part of the fluid passageway, the proximal portion has a proximal capillary lumen in fluid communication with the distal lumen, the proximal lumen having an inner diameter relatively smaller than an inner diameter of the distal lumen so as to reduce aqueous humor flow rate and regulate pressure along the proximal capillary lumen sufficient to prevent ocular hypotony; A shunt fixator is slidably positioned on the distal portion of the elongated duct to fix the distal portion of the duct within the scleral channel at a desired location determined by the required length of the shunt. A shunt is provided, comprising:

[0016] The chamber in which the shunt is implanted may be the anterior or posterior chamber or the vitreous chamber.

[0017] The shunt can be configured to resist the flow of aqueous humor at a flow rate through the shunt of 1.5 to 3.0 micrometers per minute, using the Hagen-Poiseuille equation and a viscosity coefficient of 7.042 cP. More particularly, the shunt can be configured to resist the flow of aqueous humor at a flow rate through the shunt of about 2 micrometers per minute.

[0018] The distal lumen may have a diameter between 0.12 mm and 0.3 mm. More particularly, the distal lumen may have a diameter of about 0.2 mm.

[0019] The proximal capillary lumen may have a diameter between 0.035 mm and 0.06 mm. More particularly, the diameter of the proximal capillary lumen may be about 0.05 mm.

[0020] The distal portion can have a length between 4 mm and 30 mm after being cut by the physician. The proximal portion can have a length between 1 mm and 8 mm. More specifically, the proximal portion can have a length of about 5 mm.

[0021] The distal portion can be configured to provide negligible fluid flow resistance of less than 1 mmHg, and the proximal capillary portion can be configured to provide significant fluid flow resistance of between 4 and 12 mmHg.

[0022] The inner diameter of the distal lumen may be relatively greater than the inner diameter of the proximal lumen by a factor of 2 to 8.

[0023] The length of the distal portion may be relatively longer than the length of the proximal portion by a factor of 2 to 30.

[0024] In a second embodiment of the elongated duct, to facilitate adjustment of the internal resistance to fluid flow through the proximal portion of the elongated duct, the proximal portion may comprise an inner wall and an outer wall, the inner wall comprising a meltable material that melts over a period of between 4 weeks and 12 weeks.

[0025] The proximal portion of the elongated duct may be releasably connected to the distal portion of the elongated duct, or alternatively, the proximal portion of the elongated duct may be fixedly connected to the distal portion of the elongated duct.

[0026] The shunt may include a scleral foot plate operably coupled to the proximal end of the elongated duct to secure the proximal end of the elongated duct to the sclera at the site of bleb formation and to increase the surface area for drainage of aqueous humor.

[0027] The proximal end of the elongated duct may be releasably connected to the foot plate. Alternatively, the proximal end of the elongated duct may be fixedly connected to the foot plate.

[0028] The proximal portion of the elongated duct can have a rigid construction. The proximal portion can have an oval shape when viewed in cross section. The proximal portion can have a curvature that matches the anatomical curvature of the eye.

[0029] The fixator may be frictionally positioned at the distal portion of the elongated duct in an arrangement in which the coefficient of friction acting between the fixator and the elongated duct is sufficient to adequately resist movement of the fixator relative to the elongated duct when the elongated duct is implanted in the patient's scleral channel, but allows for sliding displacement of the fixator relative to the elongated duct when a moderate force is applied to the fixator by a physician.

[0030] The fixture can define an internal passageway within which the elongated duct is received and can be positioned on the elongated duct with an interference fit, with the inner diameter of the fixture being slightly smaller than the outer diameter of the distal portion of the elongated duct.

[0031] The interior passage of the fixation body and the distal portion of the elongated duct may be cylindrical.

[0032] The fixture may have a pair of laterally extending flanges projecting outwardly from opposite sides thereof.

[0033] The fixture may have a convex rounded lower surface and a substantially flat upper surface.

[0034] The stationary body may be of rigid construction.

[0035] The fixator can have an upper body portion that engages the upper side of the distal portion and a lower body portion that engages the lower side of the distal portion of the elongated duct, the upper body portion being relatively wider than the lower body portion when viewed in a side view. The asymmetric shape of the fixator resists displacement of the shunt within the scleral channel created in the scleral tissue. The asymmetric shape also causes bending of the distal portion in regions adjacent to the proximal and distal sides of both sides of the fixator to direct the distal end away from the corneal endothelium and toward the iris surface.

[0036] In certain embodiments of the fixation body, the fixation body can define a curved internal passageway in which the elongated duct is received. The curvature of the internal passageway causes the elongated duct received therein to bend, thereby resisting displacement of the shunt within the scleral channel created in the scleral tissue, and thereby directing a distal end away from the corneal endothelium and towards the patient's iris plane.

[0037] In a third embodiment of the elongate duct, the distal portion may include a wall thickness or diameter that varies along the length of the tube to facilitate adjustment of the internal resistance to fluid flow through the distal portion. More specifically, in a first example of the third embodiment, the outer diameter of the distal portion may be tapered along at least a portion of the length of the distal portion, the wall thickness remains constant, and a lumen of the distal portion having a tapered configuration is provided. In a second example of the third embodiment, the wall thickness of the distal portion may be tapered along at least a portion of the length of the distal portion, the outer diameter remains constant, and a lumen of the distal portion having a tapered configuration is provided. In use, the internal resistance to fluid flow through the distal portion may be adjusted by moving the position of the fixture along the distal portion in the region of the tapered lumen to accommodate variations in the patient's aqueous humor production rate.

[0038] According to a second aspect of the present invention there is provided a surgical method for treating glaucoma in a patient by reducing intraocular pressure in the patient's eye, comprising: opening the conjunctival / tenon's complex to create a pocket between the conjunctival / tenon's complex and the sclera; Providing a shunt as defined and described herein above in accordance with a first aspect of the present invention; sliding the fixator along the distal portion of the elongated duct until a desired fixator position is reached that corresponds to a desired length of the distal portion of the elongated duct and a desired position of the fixator along the elongated duct for fixing the distal portion at a desired position relative to the limbus; cutting a distal portion of the elongated duct to adjust the length of the elongated duct; creating a passageway through scleral tissue with a surgical instrument to form a scleral channel from an external location in the conjunctival / Tenon's pocket to the chamber from which aqueous humor is to be diverted; inserting a distal portion of the elongated duct of the shunt into the scleral channel until a distal end of the elongated duct lies within the chamber of the eye; Closure of the conjunctiva / Tenon complex with the proximal end of the shunt remaining in the pocket A surgical method is provided, comprising:

[0039] Further features of the invention are described in more detail hereinafter, by way of non-limiting examples of the invention, with reference to the accompanying drawings, as illustrated in the accompanying drawings, in which: [Brief description of the drawings]

[0040] [Figure 1] FIG. 1 shows a prior art diagram presenting anatomical details of the human eye. [Diagram 2] FIG. 2 shows a side view of a shunt for treating glaucoma according to the present invention prior to cutting the shunt to a desired length. [Diagram 3] FIG. 3 shows a top view of the shunt of FIG. [Figure 4] FIG. 4 shows a view of the distal end of the shunt of FIG. [Diagram 5] FIG. 5 shows a view of the proximal end of the shunt of FIG. [Figure 6] FIG. 6 shows a perspective view of the fixing body of the shunt of FIG. 2 as seen from above. [Figure 7] FIG. 7 shows an end view of the fixture. [Figure 8] FIG. 8 shows an end view of the opposite side of the fixture. [Figure 9] FIG. 9 shows a side view of the fixture. [Figure 10] FIG. 10 shows a cross-sectional side view of the stationary body. [Figure 11]FIG. 11 shows a side view of the shunt of FIG. 2 showing how the fixator is displaced along the distal portion of the elongated duct using forceps. [Figure 12] FIG. 12 shows a side view of the shunt of FIG. 2 showing the distal portion of the elongated duct being severed by the physician. [Figure 13] FIG. 13 shows a side view of the shunt of FIG. 2 after it has been cut to a desired length. [Figure 14] FIG. 14 shows a cross-sectional side view of the shunt of FIG. [Figure 15] FIG. 15 shows an enlarged view of detail A of FIG. [Figure 16] FIG. 16 shows how surgical instruments are used to create a channel in the sclera for insertion of the shunt of FIG. 2 into the anterior chamber of the patient's eye. [Figure 17] FIG. 17 shows the shunt of FIG. 2 with the distal portion cut to provide a relatively short section of tubing that is implanted in the anterior chamber of a patient's eye to create a bleb near the limbus. [Figure 18] FIG. 18 shows an enlarged detail B of the shunt of FIG. [Figure 19] FIG. 19 shows the implanted shunt of FIG. 2 with the distal portion cut to provide a longer section of tubing that is implanted in the anterior chamber of a patient's eye to create a bleb away from the limbus. [Figure 20] FIG. 20 shows the implanted shunt of FIG. 17 having a shorter extension tube and a foot plate connected thereto to adjust the size and location at which the bleb is formed. [Figure 21] FIG. 21 shows how surgical instruments are used to create a channel in the sclera for insertion of the shunt of FIG. 2 into the posterior chamber of a patient's eye. [Figure 22] FIG. 22 shows the shunt of FIG. 2 implanted in the posterior chamber. [Figure 23] FIG. 23 shows a perspective view from above of another embodiment of a fixation body of a shunt according to the present invention. [Figure 24] FIG. 24 shows a cross-sectional side view of the fixture of FIG. [Diagram 25] FIG. 25 shows a side cross-sectional view of a shunt including the fixation body of FIG. [Figure 26] FIG. 26 shows an enlarged detail C of the shunt of FIG. [Figure 27] FIG. 27 shows how surgical instruments are used to create a channel in the sclera for insertion of the shunt of FIG. 2 into the vitreous chamber of a patient. [Figure 28] FIG. 28 shows the shunt of FIG. 2 implanted in the vitreous chamber. [Figure 29] FIG. 29 shows an enlarged partial plan view of the proximal end of the elongated duct attached to the scleral foot plate. [Diagram 30] FIG. 30 shows how the shunt of FIG. 2 is attached to the scleral foot plate of FIG. [Diagram 31] FIG. 31 shows the proximal end of the elongated duct of the shunt of FIG. 2 attached to the scleral footplate of FIG. 29 with the distal end implanted in the anterior chamber. [Diagram 32] FIG. 32 shows a second embodiment of an elongated duct, the proximal portion having an inner wall and an outer wall, the inner wall comprising a meltable material. [Diagram 33] FIG. 33 shows a third embodiment of an elongated duct in which the distal portion has a diameter that varies along the length of the distal portion. [Diagram 34] FIG. 34 shows a third embodiment of an elongated duct in which the distal portion has a wall thickness that varies along the length of the distal portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] Referring to the drawings, a shunt for treating glaucoma by lowering intraocular pressure in a patient's eye is indicated generally at 10 .

[0042] 2-10, the shunt 10 generally comprises an elongated silicone rubber duct 12 defining a fluid passageway 14 for diverting aqueous humor from a chamber of the patient's eye, and a fixator 16 extending outwardly from the duct 12 for anchoring the duct within tissue surrounding the eye. The chamber of interest may be the anterior or posterior chamber.

[0043] The elongated duct 12 has a distal end 18 and an opposing proximal end 20, the distal end 18 being implantable in the associated eye chamber. The elongated duct has a distal portion 22 defining the distal end of the duct positionable in the patient's scleral channel, the distal portion being deformable to allow the distal portion to conform to the patient's ocular anatomy. The distal portion is also severable, allowing the physician to cut the distal portion to a desired length corresponding to the anatomical dimensions of the patient's eye and the required bleb location. As shown in Figures 6-8, an oblique cut is made in the distal portion to define a relatively sharp point at the distal end 18.1 to facilitate insertion of the distal portion along a channel defined in the scleral tissue.

[0044] The elongated duct 12 further has a proximal portion 24 having a rigid construction which defines the proximal end of the elongated duct.

[0045] The distal portion 22 has a distal lumen 26 that defines a distal part of the fluid passageway, and the proximal portion 24 has a proximal capillary lumen 28 in fluid communication with the distal lumen, the proximal lumen having an inner diameter relatively smaller than the inner diameter of the distal lumen so as to reduce the flow rate of aqueous humor along the proximal capillary lumen.

[0046] The shunt is configured to resist the flow of aqueous humor at flow rates through the shunt of 1.5 to 3.0 micrometers per minute, more specifically at about 2 micrometers per minute, using the Hagen-Poiseuille equation and a viscosity coefficient of 7.042 cP.

[0047] The distal lumen has a diameter between 0.12 mm and 0.3 mm. More particularly, the distal lumen has a diameter of about 0.2 mm.

[0048] The proximal capillary lumen has a diameter between 0.035 mm and 0.06 mm. More particularly, the diameter of the proximal capillary lumen is about 0.05 mm.

[0049] The distal portion has a length between 4 mm and 30 mm after being cut by the physician.

[0050] The proximal portion has a length between 1 mm and 8 mm. More particularly, the proximal portion is about 5 mm in length. The distal portion is configured to provide negligible fluid flow resistance of less than 1 mmHg, and the proximal capillary portion is configured to provide significant fluid flow resistance of between 4 mmHg and 12 mmHg.

[0051] The inner diameter of the distal lumen is relatively two to eight times larger than the inner diameter of the proximal lumen.

[0052] The length of the distal portion is relatively longer than the length of the proximal portion by a ratio of 2 to 30 times.

[0053] In certain embodiments of the invention, the proximal portion of the elongated duct is releasably connected to the distal portion of the elongated duct, while in other embodiments of the invention, the proximal portion of the elongated duct is fixedly connected to the distal portion of the elongated duct.

[0054] The proximal portion of the elongated duct has an oval shape when viewed in cross section. The proximal portion has a curvature that matches that of the anatomical curvature of the eye.

[0055] The anchor 14 of the shunt forms a virtual seal with the surrounding scleral tissue and, as described in more detail herein below, is slidably positioned in the distal portion of the elongated duct 12 to secure the distal portion 22 of the duct within a channel created in the scleral tissue at a desired location determined by the required length of the shunt.

[0056] The fixator 14 is frictionally positioned in the distal portion 22 of the elongated duct in an arrangement such that the coefficient of friction acting between the fixator and the elongated duct is sufficient to adequately resist movement of the fixator relative to the elongated duct after implantation, but allows for sliding displacement of the fixator relative to the elongated duct when force is applied to the fixator by the physician during implantation.

[0057] The fixator defines an internal passageway 30 within which the distal portion of the elongate duct is received. The fixator internal passageway 30 and the distal portion of the elongate duct are cylindrical. The fixator has an upper body portion 32 that engages an upper side of the distal portion and a lower body portion 34 that engages an underside of the distal portion, the upper body portion being relatively wider than the lower body portion when viewed in side view. The asymmetric shape of the fixator resists displacement of the shunt within the scleral channel created in the scleral tissue and causes the distal portion to bend away from the endothelium.

[0058] 11-20, the shunt 10 is shown implanted in the anterior chamber of a patient's eye. To determine the optimal length of the shunt, a physician first performs a visual examination of the patient's eye to measure the anatomical dimensions of the patient's eye and the ideal bleb location.

[0059] 11, the fixator 16 is then slid along the distal portion of the elongated duct by the physician grasping the fixator 16 with forceps and applying a force to the fixator in a direction to displace it along the distal portion until it reaches a desired location along the distal portion. Of importance in this regard is the location where the physician desires to form a bleb into which aqueous humor from the anterior chamber can drain after implantation of the shunt.

[0060] As shown more clearly in FIG. 15, the inner diameter of the interior passage 30 of the fixture is slightly smaller than the outer diameter of the distal portion of the elongated duct, so that the fixture is positioned in the distal portion 22 of the duct 12 in an interference fit that allows sliding displacement of the fixture when sufficient force is applied to the fixture to overcome the frictional forces holding it in its distal position.

[0061] 12-14, the distal portion 22 of the elongated duct 12 of the shunt is then cut by the surgeon using surgical scissors S to adjust the length of the shunt to the desired length. More specifically, an angled bevel cut is made on the distal portion to provide a distal end 18.1 with a sharp point to facilitate insertion of the distal portion into the anterior or posterior chamber along the scleral channel.

[0062] 16, a portion T of the conjunctival-tenon's complex is directed backwards away from the limbus. A passageway is then created through the scleral tissue by the physician using a surgical blade I to form a scleral channel from an external location with an entry point approximately 3 mm from the limbus to an exit point at the trabecular meshwork into the anterior chamber. The distal portion of the elongated duct of the shunt is then inserted into the scleral channel until the fixator is located within the scleral channel and the distal end of the elongated duct is located within the anterior chamber.

[0063] Figure 17 shows the shunt 10 being implanted in the anterior chamber of a patient's eye to provide a channel along which aqueous humor drains from the anterior chamber to a bleb formed between the scleral tissue and the conjunctiva-Tenon's complex near the limbus, and Figure 18 shows the fixator gripping the scleral tissue within the scleral channel.

[0064] Referring to FIG. 19, the shunt 10 is shown with the anchor adjusted to be closer to the distal end, and the shunt cut and shortened to effectively adjust the location where the bleb is formed.

[0065] Referring to FIG. 20, the shunt 10 is shown with a Barbelt device 40 attached to it and positioned at the base of a bleb formed between the scleral tissue and the conjunctiva-Tenon's complex.

[0066] 21 and 22, the shunt 10 is shown in use as implanted in the posterior chamber. The shunt 10 is implanted in the same manner as described above for implanting a shunt in the anterior chamber, with the only difference being that a scleral channel is formed with an exit point into the posterior chamber at the ciliary sulcus.

[0067] The shunt 10 provides an extended length, deformable tube onto which a fixation body is slidably positioned so that the physician can adjust the position of the fixation body along the elongated duct, thereby adjusting the length of the shunt to the anatomical dimensions of the patient's eye and optimally positioning the bleb into which aqueous humor can drain.

[0068] The proximal portion of the elongated duct provides a shunt with a capillary valve, and the distal portion of the elongated duct can be cut to adjust the length of the shunt without affecting the capillary valve or significantly changing the resistance to fluid flow along the fluid passageway of the shunt.

[0069] The interference fit of the fixator onto the distal portion of the shunt provides resistance to movement of the fixator along the elongate duct when the shunt is implanted while allowing movement along the distal portion to adjust the length of the shunt. Additionally, the outwardly protruding configuration creates a fluid seal in the scleral channel.

[0070] The asymmetric shape of the fixator resists displacement of the shunt within the scleral channel created in the scleral tissue and creates a bend away from the endothelium as described herein above.

[0071] 23 and 24 show another embodiment of a fixator of a shunt according to the present invention, which is designated by the reference numeral 116. The fixator 116 is similar to the fixator 16, and features of the fixator 116 which are the same and / or similar to features of the fixator 116 are designated by the same and / or similar reference numerals in FIGS. 23 and 24. The fixator 116 defines a curved interior passageway 130 within which the distal portion 22 of the elongated duct is received, the curvature of the interior passageway 130 being configured to cause bending of the elongated duct when received therein, thereby resisting displacement of the shunt within the scleral channel created in the scleral tissue and directing the distal end away from the corneal endothelium towards the iris plane of the patient.

[0072] 25 and 26 show a shunt according to the invention including a fixture 116 showing how the elongated duct is bent by the fixture.

[0073] 27 and 28, the shunt 10 is shown in use as it is implanted in the vitreous chamber. The shunt 10 is implanted in the same manner as described above for implanting a shunt in the anterior chamber, with the only difference being that a scleral channel is formed in the squamous region of the ciliary body to have an exit point into the vitreous cavity.

[0074] 29-31, the shunt 10 includes a scleral foot plate 50 operably coupled to the proximal end 20 of the elongated duct 12 for securing the proximal end of the elongated duct to the sclera at the site of formation of the bleb. The proximal shunt portion 24 is grasped by the physician using forceps 52 and attached to a receiving recess 54 in the foot plate. The proximal end of the elongated duct may be releasably coupled to the foot plate. Alternatively, the proximal end of the elongated duct may be fixedly coupled to the foot plate. The scleral foot plate generally increases the surface area of ​​the bleb in patients with unhealthy conjunctiva.

[0075] Referring to FIG. 32, a second embodiment of an elongated duct is designated by the reference number 112. The duct 112 is similar to the elongated duct 12, with the only difference being that the proximal portion 24 initially comprises an inner wall 56 in addition to the outer wall 58, the inner wall 56 comprising a meltable material that melts over a period T of 4 to 12 weeks to facilitate adjustment of the internal resistance to fluid flow through the proximal portion of the elongated duct. At the start of the period T, the inner wall provides a relatively high resistance that gradually decreases as the inner wall melts until it is melted at the end of the period T as shown in FIG. 32. The inner wall 56 initially defines a relatively narrow lumen 26.1, and after the inner wall is melted, the outer wall defines a larger diameter lumen 26.2.

[0076] Referring to FIG. 33, a first example of a third embodiment of an elongated duct is designated by reference numeral 212. The elongated duct has a distal portion 122 having a constant wall thickness and an outer diameter that varies along the length of the distal portion (from a relatively large outer diameter OD to a relatively small outer diameter od). The outer diameter of the distal portion 122 is larger than the inner diameter of the internal passage 30 of the fixture 16, such that when the distal portion 122 is received in the internal passage 30, the wall of the distal portion deforms inwardly. The diameter of the distal portion is tapered along at least a portion of the length of the distal portion, such that the lumen 126 has a tapered configuration. The diameter of the lumen 126 tapers from a relatively large diameter DL to a relatively small diameter dl, while the wall thickness t remains constant. In use, the internal resistance to fluid flow through the distal portion can be adjusted by moving the position of the fixture along the distal portion to accommodate variations in the patient's aqueous humor production rate. The elongated duct 212, when received in the internal passage 30 of the fixation body, is clamped by the fixation body 16, causing an inward deformation of the duct in the region of the fixation body, thereby narrowing its lumen.

[0077] Referring to FIG. 34, a second example of a third embodiment of an elongated duct is designated by reference numeral 312. The elongated duct has a distal portion 222 having a constant outer diameter and a wall thickness that varies along the length of the tube (from a relatively large wall thickness T to a relatively small wall thickness t). The outer diameter of the distal portion 122 is greater than the inner diameter of the interior passageway 30 of the fixture such that when the distal portion 122 is received in the interior passageway 30, the wall of the distal portion deforms inwardly. The wall thickness of the distal portion tapers in thickness along at least a portion of the length of the distal portion. The diameter of the lumen 226 tapers from a relatively large diameter DL to a relatively small diameter dl. In use, the internal resistance to fluid flow through the distal portion can be adjusted by moving the position of the fixture along the distal portion to accommodate variations in the patient's aqueous humor production rate. The elongated duct 212, when received in the internal passage 30 of the fixation body, is clamped by the fixation body 16, causing an inward deformation of the duct in the region of the fixation body, thereby narrowing its lumen.

[0078] In summary, a surgical method for treating glaucoma in a patient by reducing intraocular pressure in the patient's eye includes: Providing a shunt 10 as defined and described herein above; measuring the anatomical dimensions of the patient's eye and the distance to a desired location for formation of a bleb into which aqueous humor can drain to determine an optimal length for the shunt; sliding the anchor 16, 116 along the distal portion 22 of the elongated duct 12 until a desired anchor position is reached that corresponds to a desired length of the distal portion of the elongated duct and a desired location of the anchor along the elongated duct for anchoring the distal portion within the scleral channel; cutting a distal portion of the elongated duct to adjust the length of the elongated duct; opening the conjunctiva / Tenon's complex to create a pocket between the conjunctiva / Tenon's complex and the sclera; Creating a passage through the scleral tissue with a surgical blade I to form a scleral channel from an external location in the conjunctival / Tenon's pocket to the anterior / posterior chambers from which aqueous humor is to be diverted; Inserting the distal portion of the elongated duct of the shunt into the scleral channel until the fixation body 16, 116 is located in the scleral channel and the distal end 18.1 of the elongated duct is located within the anterior / posterior chamber of the eye; Closure of the conjunctiva / Tenon complex with the proximal end of the shunt remaining in the pocket Includes.

[0079] The shunts and methods described hereinabove ameliorate the shortcomings of the prior art devices discussed above.

Claims

1. 1. A shunt for treating glaucoma by reducing intraocular pressure in a patient's eye, comprising: an elongated duct defining a fluid passageway for diverting aqueous humor from a chamber of the eye, the elongated duct having a distal end implantable in the chamber and an opposite proximal end; a fixed body extending outward from the elongated duct; 1. A shunt comprising: the fixator of the shunt is slidably positioned on the distal portion of the elongate duct to fixate the distal portion of the elongate duct at a desired position within a scleral channel created in the patient's scleral tissue; the fixator has an internal passage configured to receive the elongated duct therein and to frictionally engage the surrounding scleral tissue defining the scleral channel, the fixator being positioned on the elongated duct with an interference fit, and an inner diameter of the fixator being slightly smaller than an outer diameter of the distal portion of the elongated duct.

2. A shunt as described in claim 1, wherein the fixed body has a pair of laterally extending flanges that protrude outward from the fixed body in opposite directions.

3. 2. The shunt of claim 1, wherein the fixator is frictionally positioned at the distal portion of the elongated duct in an arrangement in which the coefficient of friction between the fixator and the elongated duct is sufficient to adequately resist movement of the fixator relative to the elongated duct when the elongated duct is implanted in the scleral channel of the patient, but allows sliding displacement of the fixator relative to the elongated duct when a moderate force is applied to the fixator by a physician.

4. 2. The shunt of claim 1, wherein the fixation body has a first body portion configured to engage with a first side of the distal portion and a second body portion configured to engage with a second opposite side of the distal portion, the first body portion being relatively wider than the second body portion when viewed in a side view so as to cause bending of the elongated duct in regions adjacent to the proximal and distal sides of both sides of the fixation body when the distal portion of the elongated duct is received in the internal passage of the fixation body, thereby resisting displacement of the shunt within a scleral channel created in scleral tissue and directing the distal end away from the corneal endothelium and toward the patient's iris plane.

5. 2. The shunt of claim 1, wherein the fixation body defines a curved internal passageway into which the elongated duct is received, the curvature of the internal passageway being configured to cause the elongated duct to bend when received therein, thereby resisting displacement of the shunt within a scleral channel created in scleral tissue and directing the distal end away from the corneal endothelium and toward the patient's iris plane.

6. 2. The shunt of claim 1, wherein to facilitate adjustment of internal resistance to fluid flow through the distal portion of the elongated duct, the distal portion has a wall thickness or diameter that varies along the length of the distal portion such that the internal flow resistance can be adjusted by sliding the fixture along the distal portion.

7. 2. The shunt of claim 1, wherein the shunt includes a scleral footplate operably connected to the proximal end of the elongated duct to secure the proximal end of the elongated duct to the sclera at the site of bleb formation and increase the surface area for aqueous humor drainage.

8. A shunt as described in claim 1, wherein the proximal portion of the elongated duct has an inner wall and an outer wall to facilitate adjustment of internal resistance to fluid flow through the proximal portion, and the inner wall comprises a meltable material that melts over a period of 4 to 12 weeks.

9. A shunt as described in claim 1, wherein the elongated duct includes a proximal portion connected to the distal portion of the elongated duct.

10. The shunt of claim 9, wherein the proximal portion is releasably connected to the distal portion.

11. The shunt of claim 9 , wherein the proximal portion of the elongate duct is fixedly connected to the distal portion of the elongate duct.

12. The shunt of claim 9 , wherein the proximal portion of the elongated duct has a rigid structure.

13. The shunt of claim 9 , wherein the proximal portion has an oval shape when viewed in cross section.

14. 10. The shunt of claim 9, wherein the proximal portion has a curvature that matches that of the anatomical curvature of the eye.

15. The shunt of claim 1 , wherein the fixation body is of rigid structure.

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