Shunt and method for treating an ocular disorder of pressure

Abstract

A shunt 10 for treating glaucoma by lowering intraocular pressure in an eye of a patient, comprises an elongate duct 12 having a lumen 15 for diverting aqueous humor from a chamber of the eye, and a removable intraluminal filament 24 received in the lumen. A distal end of the duct is implantable in the anterior chamber and an opposite proximal end is implantable in a channel formed in the sclera adjacent the anterior chamber. The intraluminal filament 24 emanates from the proximal end of the elongate duct, for regulating resistance to fluid flow through the lumen. The intraluminal filament 24 has a number of enlarged fixation formations 26 located within the conjunctival / tenon's complex for resisting migration of the intraluminal filament following implantation. The intraluminal filament can be partially or completely withdrawn from the elongate duct in order to reduce resistance to fluid flow and further regulate intraocular pressure following implantation of the shunt.

Description

[0001] SHUNT AND METHOD FOR TREATING AN OCULAR DISORDER OF PRESSURE

[0002] TECHNICAL FIELD

[0003] This invention relates to a shunt for treating an ocular disorder of pressure in a patient. The invention relates also to a method for treating an ocular disorder of pressure in a patient. More specifically, the invention relates to a shunt and method for treating an ocular disorder of pressure in a patient by diverting aqueous fluid from a chamber of the eye to an extraocular space of the patient surrounding an ocular globe of the eye.

[0004] BACKGROUND TO INVENTION

[0005] Glaucoma is an ocular disorder of pressure, characterised by the presence of raised intraocular pressure (IOP) causing irreversible damage to the optic nerve. The ocular globe of the eye has a tough outer layer comprised of the sclera and the cornea. The internal areas of the eye are separated into the anterior segment and the posterior segment. The anterior segment comprises the anterior and posterior chambers of the eye filled with aqueous fluid, and the posterior segment comprises the vitreous chamber filled with vitreous gel. The cornea merges into the sclera at a juncture referred to as the limbus. A portion of the sclera is covered by a thin tissue called Tenon's membrane (also called Tenon's capsule), which envelopes the bulb of the eye from the optic nerve sheath to the ciliary region. The optic nerve sheath envelopes the subarachnoid space surrounding the optic nerve. An anterior portion of the Tenon’s membrane is covered by another thin tissue membrane known as the conjunctiva. Near its front, the Tenon's membrane blends into the conjunctiva where it is attached to the ciliary region of the eye. The Tenon’s membrane is surrounded by orbital fat in the posterior region.

[0006] The ocular globe maintains an internal pressure known as the intraocular pressure which normally varies between 10 mmHg and 21 mmHg. The intraocular pressure needs to be controlled within a defined range in order for the eye to function normally. The intraocular pressure is regulated by maintaining a balance between volumes of aqueous fluid produced and drained from the anterior segment of the ocular globe. Aqueous fluid is produced by the ciliary body at a rate which varies between 2 to 3 micromillimetres per minute. Age is one factor which affects the aqueous production rate, with elderly patients having a lower aqueous production rate than younger patients. Aqueous fluid is drained from the anterior chamber through the trabecular and uveoscleral pathways at variable rates. If an impairment occurs in a reduced amount of aqueous fluid drained from the ocular globe, then the intraocular pressure becomes too high. This causes damage to the optic nerve head known as glaucoma. Glaucoma causes irreversible visual field defects. These defects enlarge until a patient’s field of view is severely restricted. In the end stage of the disease, total vision loss occurs. Glaucoma is a leading cause of blindness worldwide. If the intraocular pressure remains very high, the eye can become persistently painful and may need to be removed.

[0007] Current medical, laser and surgical treatment options for glaucoma are aimed at lowering intraocular pressure. Glaucoma which is difficult to control through first line therapies such as topical medications and laser therapy is known as refractory glaucoma. Refractory glaucoma is often managed by the implantation of a glaucoma drainage device to create an additional aqueous outflow pathway from the anterior chamber into the subconjunctival space. Aqueous fluid 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 a fibrovascular wall of Tenon's tissue. In the early weeks following implantation, the bleb wall is not well formed and resistance to fluid flowing into the subconjunctival space, is minimal. This means that glaucoma drainage devices tend to over-drain in the early stages. Due to over-drainage in the early stages, the IOP may drop below 5mmHg. This causes a condition known as hypotony. Hypotony may cause complications such as maculopathy and choroidal effusion.

[0008] The resistance to flow into the bleb then gradually increases during bleb wall formation in the intermediate period between 4 and 12 weeks following implantation. The final resistance to fluid flow through the drainage device equates to the sum of the internal flow resistance provided by the drainage device and the flow resistance provided by the subconjunctival space. It is therefore preferable for drainage devices to provide higher resistance to fluid flow in the early period following implantation to prevent hypotony, and lower resistance to flow in the intermediate to later stages to increase aqueous drainage.

[0009] Aqueous drainage devices such as the Applicant’s Liqid Medical device (WO2023 / 135549), the Ahmed device (US Patent 5,071 ,408) and the Innfocus device (US Patent 9,101 ,444) prevent early hypotony by providing a resistance to fluid flow which keeps the IOP above 5 mmHg even when no bleb wall has formed and there is minimal resistance to fluid drainage provided by the subconjunctival space. The shortcoming of these drainage devices is that the resistance to fluid flow is fixed, and this means that final resistance to fluid flow is higher than desired and aqueous drainage rates decrease. This results in raised IOP and the progression of glaucoma.

[0010] Certain aqueous drainage devices such as the Baerveldt device (US Patent 10,492,948) have been described for use with intraluminal filaments such as sutures. These filaments initially increase the resistance to flow to prevent hypotony, and can be removed following bleb wall formation to reduce the internal flow resistance and prevent IOP increases. However, these filaments have three major shortcomings. Firstly, the filaments have no in-built mechanism for preventing migration of the filament following implantation. This means that the filaments usually need to be buried within scleral or corneal tissue using needle bodies which is invasive and time-consuming. Secondly, the filaments have no mechanism for identifying how much of the filament has been withdrawn from the lumen of the drainage device which means that flow control through the lumen of the device cannot be titrated. Thirdly, the filaments emanate from the proximal opening of the tube lumen and are then directed away towards a position which is off-axis from the drainage tube. This means that the path of the filament is not parallel to the path of the tube, and when the filament is removed by the surgeon who pulls the free end of the filament, a tangential force is applied to the tube which may cause difficulty removing the filament, or may cause the tube to bend during removal of the filament resulting in the risk of bleeding from adjacent blood vessels.

[0011] It is an object of the present invention to provide a shunt and a method for treating an ocular disorder in a patient which address some or all of the abovementioned three shortcomings.

[0012] In this specification, the term "ocular disorders of pressure" should be interpreted broadly to include, but not necessarily limited to, glaucoma, Idiopathic Intracranial Hypertension (IIH), and Spaceflight Associated Neuro-ocular Syndrome (SANS) and hypotony.

[0013] In this specification, the term “distal” means in the direction of the eye of a patient or away from a user of the shunt, while the term “proximal” means in the direction away from the eye of the patient or towards the user of the shunt.

[0014] In this specification, any reference to "ocular globe" should be interpreted broadly to include a reference to the scleral and corneal tissues.

[0015] SUMMARY OF INVENTION

[0016] According to a first aspect of the invention there is provided a shunt for treating ocular disorders of pressure in an eye of a patient, the shunt comprising: an elongate duct having a lumen providing a fluid passageway for diverting aqueous humor from a chamber of the eye, the elongate duct having an open distal end and an opposite open proximal end, the distal end being implantable in the chamber of the eye and the proximal end being implantable in an extraocular space surrounding an ocular globe of the eye; and a removable intraluminal filament for regulating resistance to fluid flow through the lumen of the elongate duct, the intraluminal filament having a distal end and a proximal end, wherein a distal end region of the intraluminal filament is positioned within the lumen of the elongate duct and a proximal free end region of the intraluminal filament is disposed externally of the elongate duct, the shunt being characterized in that one or both of the elongate duct and the intraluminal filament have migration resistance means for resisting migration of the intraluminal filament following implantation of the shunt, yet allowing the intraluminal filament to be withdrawn, partially or completely, from the elongate duct through the opening, by pulling on the filament in order to reduce the resistance to fluid flow and further regulate intraocular pressure following implantation of the shunt.

[0017] In a particular embodiment of the invention, the migration resistance means may comprise at least one filament fixation formation located at the proximal free end region of the intraluminal filament, the filament fixation formation being configured to engage surrounding ocular or extraocular tissue and resist migration of the intraluminal filament following implantation of the shunt, yet allow the intraluminal filament to be withdrawn from the elongate duct partially or completely by pulling on the filament in order to reduce the resistance to fluid flow.

[0018] The filament may be of an absorbent or non-absorbent material selected from the group consisting of polyetheretherketone, nylon, polyamide, polypropylene, silk, polyurethane, polyester, polycarbonate, monocryl, catgut, polyglactin and polydioxanone. More particularly, the filament may comprise a monofilament or a braided filament.

[0019] In different embodiments of the invention, the filament fixation formation may have different configurations wherein a portion of the filament fixing formation extends laterally outwardly so as to engage surrounding conjunctival tissue. More specifically, the filament fixation formation may comprise an enlarged formation such as a bead, knot, loop, stamp, kink, barb, fray, or bend in the filament.

[0020] The intraluminal filament may have a number of filament fixation formations at spaced locations along the length of the filament.

[0021] The intraluminal filament may extend through the proximal end or the distal end of the elongate duct, permitting withdrawal of the intraluminal filament from the lumen of the elongate duct.

[0022] In another embodiment of the shunt, the elongate duct has an opening in a side wall thereof through which the intraluminal filament extends and can be withdrawn from the lumen of the elongate duct, by applying a traction force.

[0023] In the embodiment of the shunt wherein the intraluminal filament emanates from the side wall of the elongate duct, the migration resistance means may be in the form of an interference fit between the side wall opening and the intraluminal filament such that the interference fit resists migration of the intraluminal filament following implantation of the shunt, yet allows the intraluminal filament to be withdrawn from the elongate duct partially or completely by pulling the filament in order to reduce the resistance to fluid flow. In order to achieve the interference fit, the diameter of the side wall opening and the cross-sectional dimensions of the intraluminal filament are such that a predetermined interference fit is achieved between the side wall opening and the filament offering a predetermined degree of resistance to displacement of the filament within the side wall opening. In the embodiment of the shunt wherein the intraluminal filament emanates from the side wall of the elongate duct, the intraluminal filament may be characterized by an absence of fixation formations, with sufficient migration resistance being provided by the interference fit as described hereinabove.

[0024] In an alternative version of the embodiment of the shunt wherein the intraluminal filament emanates from the side wall of the elongate duct, the migration resistance means may comprise one or more of the filament fixation formations located at the proximal free end region of the intraluminal filament.

[0025] The spacing between the filament fixation formations may serve as a guide to a surgeon indicating the amount of the filament disposed externally of the elongate duct. As such, the spacing between the filament fixation formations may be equal. In an alternative embodiment, the spacing between the filament fixation formations may vary.

[0026] The elongate duct may define a capillary lumen section having a relatively smaller internal diameter than an internal diameter of the lumen of the remainder of the elongate duct, wherein the smaller internal diameter of the capillary lumen section, is sufficient to reduce a flow rate of aqueous humor and regulate pressure along the elongate duct in order to prevent hypotony.

[0027] The chamber of the eye in which the distal region of the shunt is implanted may be the anterior chamber, the posterior chamber or the vitreous chamber of the eye.

[0028] The extraocular space in which the proximal end region of the shunt is implanted, may be any extraocular space including, but not necessarily limited to the ocular surface space, sub-Tenon’s space, the suprachoroidal space, the intra-orbital space, the paranasal sinuses or the subarachnoid space.

[0029] According to a second aspect of the invention, there is provided a method treating glaucoma by lowering intraocular pressure in an eye of a patient, the method including: providing the shunt as defined and described in accordance with the first aspect of the invention; opening the conjunctival / tenon’s complex to expose the underlying sclera; using a cutting surgical instrument, creating a passageway through scleral tissue so as to form a scleral channel from an external position to a chamber of the eye from which aqueous fluid is to be diverted; inserting the distal portion of the elongate duct of the shunt into the scleral channel until the distal end of the elongate duct lies within the chamber of the eye; positioning the proximal end region of the elongate duct in an extraocular space surrounding the ocular globe; and closing the conjunctival / tenon’s complex leaving the proximal end of the shunt lying within the extraocular space.

[0030] The proximal end of the filament may be left to lie within the extraocular space, or may be buried within the wall of the ocular globe, and / or the conjunctiva / tenon’s complex, or may be passed through the wall of the ocular globe and / or the conjunctiva / tenon’s complex, to be left with a portion exposed on the surface of the eye.

[0031] The method may include withdrawing a predetermined amount of the filament from the elongate duct, or advancing a predetermined amount of the filament further into the elongate duct, as required upon implantation of the shunt, in order initially to provide a desired resistance to fluid flow along the elongate duct.

[0032] At a point in time following implantation of the shunt, the method may include withdrawing a predetermined amount of the filament from the elongate duct as required in order to provide a desired reduced resistance to fluid flow along the elongate duct in order to regulate IOP in the post operative period. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Further features of the invention are described in more detail hereinafter, by way of a non-limiting example of the invention, with reference to and as illustrated in the accompanying diagrammatic drawings. In the drawings:

[0034] Figure 1 shows a diagrammatic illustration of a human eye providing anatomical information on a human eye, the illustration being provided solely for reference purposes;

[0035] Figure 2 shows a perspective view of a shunt in accordance with the invention, with an intraluminal filament having fixation formations, located in the lumen of the elongate duct of the shunt and wherein the intraluminal filament emanates from the proximal end of the elongate duct;

[0036] Figure 2A shows an end view of the shunt of Figure 2, as seen from the proximal end thereof;

[0037] Figure 3 shows a perspective view of the shunt of Figure 2, wherein the intraluminal filament has been removed from the elongate duct of the shunt;

[0038] Figures 4A - 4J show perspective, side and top views, respectively, of different embodiments of intraluminal filaments of the shunt in accordance with the invention;

[0039] Figures 5A - 5H illustrate, in sequence, a method in accordance with the invention, of implanting the shunt of Figure 2;

[0040] Figure 6 shows a perspective view of another embodiment of a shunt in accordance with the invention wherein the intraluminal filament emanates from a side wall opening in the duct, with an intraluminal filament having fixation formations, located in the lumen of the elongate duct of the shunt;

[0041] Figure 6A shows a perspective view of a further embodiment of a shunt in accordance with the invention wherein the intraluminal filament emanates from a side wall opening in the duct, and is characterized by an absence of fixation formations;

[0042] Figures 7A - 7H illustrate, in sequence, a method in accordance with the invention, of implanting the shunt of Figure 6;

[0043] Figure 8 shows a perspective view of yet a further embodiment of a shunt in accordance with the invention, with an intraluminal filament having fixation formations, located in the lumen of the elongate duct of the shunt and wherein the intraluminal filament emanates from the distal end of the elongate duct; and

[0044] Figures 9A - 9F illustrate, in sequence, a method in accordance with the invention, of implanting the shunt of Figure 8.

[0045] DETAILED DESCRIPTION OF THE DRAWINGS

[0046] An example of a shunt in accordance with the first aspect of the invention, for treating glaucoma by lowering intraocular pressure in an eye of a patient, is designated in the drawings by the reference numeral 10. For background and nomenclature purposes, anatomic details of a human eye are illustrated in Figure 1 .

[0047] The shunt 10 comprises, broadly, an elongate duct 12 having a lumen 15 and a removable intraluminal filament 24 receivable in the lumen of the elongate duct.

[0048] The lumen 15 provides a fluid passageway for diverting aqueous humor from a chamber of the eye, such as the anterior chamber of the eye as illustrated and described in this example. The elongate duct has a distal end 20 and an opposite proximal end 18, the distal end being implantable in the anterior chamber of the eye and the proximal end being implantable in a channel formed in a region of the sclera adjacent the anterior chamber. The distal end has a bevel cut so as to define a relatively sharp point for facilitating insertion of the distal end along a channel defined in ocular tissue.

[0049] The elongate duct has a distal portion 14 defining the distal end 20 and a relatively shorter proximal portion 16 defining the proximal end 18. The proximal portion is of a rigid construction and has a smaller external diameter compared to an external diameter of the distal portion. The distal portion is deformable so as to permit the distal portion to conform to anatomical structures of the eye of the patient. The distal portion defines the distal end and a distal lumen providing a distal part of the fluid passageway while the proximal portion defines the proximal end and a proximal capillary lumen which is in fluid flow communication with the distal lumen The proximal lumen has an internal diameter which is relatively smaller than an internal diameter of the distal lumen so as to reduce a flow rate of aqueous humor and regulate pressure along the proximal capillary lumen sufficient to prevent hypotony.

[0050] The intraluminal filament 24 emanates from the proximal end of the elongate duct, for regulating resistance to fluid flow through the lumen of the elongate duct. The intraluminal filament 24 has a first end 27.1 and a second end 27.2, wherein at least part of a first end region of the intraluminal filament is located within the lumen of the elongate duct and a second end region of the intraluminal filament is disposed externally of the elongate duct.

[0051] The second end region of the intraluminal filament 24 is designed to be located within the conjunctival / tenon’s complex of the patient and has migration resistance means comprising a number of filament fixation formations 26 for preventing migration of the intraluminal filament following implantation of the shunt. The filament fixation formations 26 are configured so as to initially provide sufficient resistance to migration of the intraluminal filament following implantation of the shunt, yet still allow the intraluminal filament to be partially of completely withdrawn from the elongate duct by a surgeon pulling the filament, in order to reduce resistance to fluid flow and further regulate intraocular pressure following implantation of the shunt. In this manner, the degree of resistance to fluid flow along the elongate duct, can be adjusted.

[0052] The filament is of an absorbent or non-absorbent material selected from the group consisting of nylon, polyamide, polypropylene, silk, polyurethane, polyester, polycarbonate, monocryl, catgut, polyglactin and polydioxanone. More particularly, the filament may comprise a monofilament or a braided filament.

[0053] In different embodiments of the invention, the filament fixation formations have different configurations wherein a portion of each filament fixation formation 26 extends laterally outwardly so as to engage surrounding conjunctival tissue.

[0054] The filament fixation formations 26 are spaced along a length of the proximal end region of the intraluminal filament 24 which is intended to be located within surrounding conjunctival tissue upon implantation of the shunt. In an alternative embodiment, the intraluminal filament may have a number of spaced filament fixation formations 26 along the entire length thereof.

[0055] In addition to resisting migration of the intraluminal filament 24 within the scleral channel of the patient so as to ensure that the desired level of resistance to fluid flow is maintained, the filament fixation formations 26 may be spaced from one another wherein the spacing between the filament fixation formations serves as a guide to a surgeon indicating the amount of the filament disposed in the lumen of the elongate duct and thereby the degree of resistance to fluid flow provided by the intraluminal filament.

[0056] As such, the spacing between the filament fixation formations 26 may be equal. In an alternative embodiment, the spacing between the filament fixation formations 26 may vary as may be desirable for the purpose of resisting migration and / or to serve as a guide to a surgeon as to the amount of the intraluminal filament disposed in the elongate duct. With reference to Figures 4A - 4J a number of different configurations of the fixing formations 26 are illustrated. In Figures 4A1 - 4A3, an intraluminal filament 24.1 having spaced filament fixation formations in the form of loops 26.1 formed in the filament, is shown. In Figures 4B1 - 4B3, an intraluminal filament 24.2 having spaced fixing formations in the form of knots 26.2 formed in the filament, is shown. In Figures 4C1 - 4C3, an intraluminal filament 24.3 having spaced filament fixation formations in the form of flat oval-shaped discs 26.3 stamped in the filament, is shown. In Figures 4A1 - 4A3, an intraluminal filament 24.1 having spaced filament fixation formations 26.1 in the form of loops formed in the filament, is shown. In Figures 4D1 - 4D3, an intraluminal filament 24.4 having spaced filament fixation formations in the form of pairs of angularly offset oval-shaped discs 26.4 stamped in the filament, is shown. In Figures 4E1 - 4E3, an intraluminal filament 24.5 having spaced filament fixation formations in the form of triangular depressions 26.5 formed in the filament, is shown. In Figures 4F1 - 4F3, an intraluminal filament 24.1 having spaced fixing formations in the form of curved depressions 26.6 formed in the filament, is shown. In Figures 4G1 - 4G3, an intraluminal filament 24.7 having spaced filament fixation formations in the form of square-shaped depressions 26.7 formed in the filament, are shown. In Figures 4H1 - 4H3, an intraluminal filament 24.8 having spaced filament fixation formations in the form of round beads 26.8 formed on the filament, is shown. In Figures 411 - 4I3, an intraluminal filament 24.9 having spaced filament fixation formations in the form of frayed regions 26.9 formed on the filament, is shown. In Figures 4J1 - 4J3, an intraluminal filament 24.10 having spaced filament fixation formations in the form of barbs 26.10 formed on the filament, is shown.

[0057] With reference to Figures 5A - 5B, a method for treating glaucoma in a patient using the shunt 10, in accordance with the second aspect of the invention, is illustrated in sequence.

[0058] The method includes opening the conjunctival / tenon’s complex using surgical scissors 32, to form a pocket exposing the underlying sclera (see Figure 5A). The position of a proposed scleral channel is then marked (see Figure 5B). Using a cutting blade 36 of a surgical instrument, a passageway is created through scleral tissue so as to form the scleral channel extending from an external position at the pocket in the conjunctival / tenon’s complex to a chamber of the eye from which aqueous fluid is to be diverted (see Figure 5C).

[0059] The distal portion of the elongate duct 12 of the shunt 10 is then inserted into the scleral channel using surgical forceps 38 until the distal end 20 of the elongate duct lies within the anterior chamber of the eye (see Figure 5D). The distal portion of the elongate duct is sealed within the scleral tissue at a desired position relative to the limbus (see Figure 5E). The proximal end region of the elongate duct 10 is then positioned in a pocket external to the ocular globe and the pocket closed using a suture 35 (see Figure 5F) leaving the proximal end lying within the pocket. In Figure 5G, the filament 24 is shown partially retracted from the elongate duct. In Figure 5H, the filament 24 is shown fully retracted from the elongate duct.

[0060] The second end 27.2 of the filament may be left to lie within the pocket, or may be buried within the wall of the ocular globe, or may be passed through the conjunctiva / tenon’s complex to be left with a portion exposed on the surface of the eye.

[0061] Figure 6 shows another embodiment of a shunt in accordance with the invention, designated by the reference numeral 100. The shunt 100 is the similar to the shunt 10, with the only difference being that the shunt 100 has a hole 25 in a side of the elongate duct designated by the reference numeral 1 12. The same and / or similar reference numerals are used to designate features of the shunt 100 which are the same as and / or similar to features of the shunt 10.

[0062] The intraluminal filament 24 emanates from the side wall of the elongate duct through the hole 25. The migration resistance means is provided by the fixation formations 26 and also by an interference fit between the hole 25 and the intraluminal filament 24 such that the interference fit resists migration of the intraluminal filament following implantation of the shunt, yet allows the intraluminal filament to be withdrawn from the elongate duct partially or completely by pulling the filament in order to reduce the resistance to fluid flow following bleb wall formation. It will be appreciated that in order to achieve the interference fit, the diameter of the side wall opening and the cross- sectional dimensions of the intraluminal filament are such that a predetermined interference fit is achieved between the side wall opening and the filament offering a predetermined degree of resistance to displacement of the filament within the side wall opening.

[0063] The intraluminal filament 24 is received within the lumen (designated 1 15 for the shunt 100) such that the first end region 27.1 of the intraluminal filament is located within the lumen of the elongate duct and the second end region 27.2 of the intraluminal filament is disposed externally of the elongate duct, the filament extending through the hole 25 as is shown in Figure 6.

[0064] Figure 6A shows an alternative embodiment of a shunt in accordance with the invention, designated by the reference numeral 200. The shunt 200 is similar to the shunt 10, with the only difference being that the intraluminal filament 24 of the shunt 200 does not have filament fixation formations as in this instance, sufficient resistance to migration of the filament is provided by the interference fit between the hole 25 and the filament. The same and / or similar reference numerals are used to designate features of the shunt 200 which are the same as and / or similar to features of the shunt 100.

[0065] With reference to Figures 7A - 7E, a method for treating glaucoma in a patient using the shunt 100, in accordance with the second aspect of the invention, is illustrated in sequence.

[0066] The shunt 100 is implanted in similar fashion to the shunt 10. As such, the method includes opening the conjunctival / tenon’s complex to expose the underlying sclera. The position of the scleral channel is then marked. Using a cutting blade 36 of a surgical instrument, a passageway is created through scleral tissue so as to form a scleral channel from an external position to a chamber of the eye from which aqueous fluid is to be diverted. The distal portion of the elongate duct of the shunt 100 is then inserted into the scleral channel using surgical forceps 38 until the distal end 120 of the elongate duct lies within the anterior chamber of the eye (see Figure 7A). The distal portion of the elongate duct is sealed within the scleral tissue at a desired position relative to the limbus and the proximal end region of the elongate duct 10 is positioned in a pocket external to the ocular globe (see Figure 7B). The conjunctival / tenon’s complex is then closed by suture 35 (see Figure 7C) leaving the proximal end of the duct lying within the pocket. In Figure 7D, the filament 24 is shown partially retracted from the elongate duct, with the filament emanating from the hole 25 in the sidewall of the elongate duct. In Figure 7E, the filament 24 is shown fully removed from the lumen of the elongate duct.

[0067] As for the shunt 10, the proximal end of the filament may be left to lie within the pocket, or may be buried within the wall of the ocular globe, or may be passed through the conjunctiva / tenon’s complex to be left with a portion exposed on the surface of the eye.

[0068] The method further includes withdrawing a predetermined amount of the filament 24 from the elongate duct, or advancing a predetermined amount of the filament further into the elongate duct as required, upon implantation of the shunt, in order initially to provide a desired resistance to fluid flow along the elongate duct (as shown by the arrows in Figure 5G). Thereafter, the conjunctival / tenon’s complex is closed, leaving the proximal end of the shunt 10 and the filament 24 lying within the pocket. It will be appreciated that the method described herein with reference to Figures 7A - 7E applies equally to the use of the shunt 200.

[0069] Figure 8 shows yet a further embodiment of a shunt in accordance with the invention, designated by the reference numeral 300. The shunt 300 is similar to the shunt 10, with the only difference being that the intraluminal filament 24 emanates from the distal end of the elongate duct 12 of the shunt 300. As such, features of the shunt 300 which are the same as and / or similar to those of the shunt 10 are designated by the same and / or similar reference numerals in Figure 8. With reference to Figures 9A - 7F, a method for treating glaucoma in a patient using the shunt 300, in accordance with the second aspect of the invention, is illustrated in sequence.

[0070] The shunt 300 is implanted using an insertion needle 50. As such, the method includes opening the conjunctival / tenon’s complex to expose the underlying sclera. The insertion needle 50 with the shunt 300 located therein, is inserted into the eye as shown in Figure 9A to the location at which the shunt 300 is to be implanted. With reference to Figures 9B - 9C, the insertion needle is then withdrawn, leaving the shunt behind.

[0071] With reference to Figures 9D - 9F, the method further includes withdrawing a predetermined amount of the filament 24 from the elongate duct via the distal end 20 thereof, or advancing a predetermined amount of the filament further into the elongate duct as required, in order initially to provide a desired resistance to fluid flow along the elongate duct.

[0072] The shunts 10, 100, 200 and 300 described hereinabove, address the three major shortcomings described herein under the heading: “Background to Invention”. The migration resistance means prevents migration of the intraluminal filament following implantation. The filament fixation formations of the filaments also provide a mechanism for identifying how much of the filament has been withdrawn from the lumen of the drainage device which means that flow control through the lumen of the device can be titrated. Providing an opening in a side wall of the duct for the filament, allows for the addresses the problem wherein the path of the filament is not parallel to the path of the tube, causing a tangential force to be applied to the tube when removing the filament, which may cause difficulty removing the tube, or may cause the tube to bend during removal of the filament resulting in the risk of bleeding from adjacent blood vessels.

Claims

AMENDED CLAIMS received by the International Bureau on 26 May 2025 (26.05.2025)CLAIMS:1 . A shunt for treating ocular disorders of pressure in an eye of a patient, the shunt comprising: an elongate duct having a lumen providing a fluid passageway for diverting aqueous humor from a chamber of the eye, the elongate duct having an open distal end and an opposite open proximal end, the distal end being implantable in the chamber of the eye and the proximal end being implantable in an extraocular space surrounding an ocular globe of the eye; and a removable intraluminal filament for regulating resistance to fluid flow through the lumen of the elongate duct, the intraluminal filament having a distal end and a proximal end, wherein a distal end region of the intraluminal filament is positioned within the lumen of the elongate duct and a proximal free end region of the intraluminal filament is disposed externally of the elongate duct, the shunt being characterized in that one or both of the elongate duct and the intraluminal filament have migration resistance means for resisting migration of the intraluminal filament following implantation of the shunt, yet allowing the intraluminal filament to be withdrawn from the elongate duct, partially or completely, by pulling on the filament in order to reduce the resistance to fluid flow and further regulate intraocular pressure following implantation of the shunt, wherein the elongate duct has an opening in a side wall thereof through which the intraluminal filament extends and can be withdrawn from the lumen of the elongate duct by applying a traction force.

2. The shunt as claimed in claim 1 , wherein the migration resistance means comprises at least one filament fixation formation located at the proximal free end region of the intraluminal filament, the filament fixation formation being configured to engage surrounding ocular or extraocular tissue and resist migration of the intraluminal filament following implantation of the shunt, yet allow the intraluminal filament to bewithdrawn from the elongate duct partially or completely by pulling on the filament in order to reduce the resistance to fluid flow.

3. The shunt as claimed in claim 2, wherein the filament is of an absorbent or nonabsorbent material selected from the group consisting of polyetheretherketone, nylon, polyamide, polypropylene, silk, polyurethane, polyester, polycarbonate, monocryl, catgut, polyglactin and polydioxanone.

4. The shunt as claimed in claim 2, wherein the filament comprises a monofilament or a braided filament.

5. The shunt as claimed in claim 2, wherein a portion of the filament fixation formation extends laterally outwardly so as to engage surrounding conjunctival tissue.

6. The shunt as claimed in claim 5, wherein the filament fixation formation comprises an enlarged formation such as a bead, knot, loop, stamp, kink, barb, fray, or bend in the filament.

7. The shunt as claimed in claim 2, wherein the intraluminal filament has a number of filament fixation formations at spaced locations along the length of the filament.

8. The shunt as claimed in claim 2, wherein the intraluminal filament extends through the proximal end or the distal end of the elongate duct, permitting withdrawal of the intraluminal filament from the lumen of the elongate duct.

9. The shunt as claimed in claim 1 , wherein the intraluminal filament is characterized by an absence of filament fixation formations, the migration resistance means comprising an interference fit between the side wall opening and the intraluminal filament such that the interference fit resists migration of the intraluminal filament following implantation of the shunt, yet allows the intraluminal filament to be withdrawn from the elongate duct partially or completely by pulling on the filament in order to reduce the resistance to fluid flow.

10. The shunt as claimed in claim 1 , wherein the migration resistance means comprises one or more of the filament fixation formations located at the proximal free end region of the intraluminal filament.11 . The shunt as claimed in claim 1 , wherein the elongate duct defines a capillary lumen section having a relatively smaller internal diameter than an internal diameter of the lumen of the remainder of the elongate duct, wherein the smaller internal diameter of the capillary lumen section, is sufficient to reduce a flow rate of aqueous humor and regulate pressure along the elongate duct in order to prevent hypotony.

12. A method for treating ocular disorders of pressure in an eye of a patient, the method including: providing the shunt in accordance with any one of claims 1 to 1 1 ; using a cutting surgical instrument, creating a passageway through the ocular globe so as to form a channel from an external position to a chamber of the eye from which aqueous fluid is to be diverted; inserting the distal portion of the elongate duct of the shunt into the channel until the distal end of the elongate duct lies within the chamber of the eye; and positioning the proximal end region of the elongate duct in an extraocular space surrounding the ocular globe, wherein the proximal end of the filament is left to lie within the extraocular space, or buried within the wall of the ocular globe, and / or the conjunctiva / tenon’s complex, or passed through a wall of the ocular globe and / or the conjunctiva / tenon’s complex, to be left with a portion exposed on the surface of the eye.

13. The method as claimed in claim 12, which includes withdrawing a predetermined amount of the filament from the elongate duct, or advancing a predetermined amount of the filament further into the elongate duct, as required prior toimplantation of the shunt, in order initially to provide a desired resistance to fluid flow along the elongate duct.

14. The method as claimed in claim 12, wherein following implantation of the shunt, the method includes withdrawing a predetermined amount of the filament from the elongate duct as required in order to provide a desired reduced resistance to fluid flow along the elongate duct in order to regulate intra-ocular pressure in a postoperative period.

15. The method as claimed in claim 12, wherein the method includes opening the conjunctival / tenon's complex to expose the underlying sclera and creating said passageway in the sclera so as to form a scleral channel into which the distal portion of the elongate is inserted until the distal end of the elongate duct lies within the chamber of the eye.

16. The method as claimed in claim 15, wherein the method includes closing the conjunctival / tenon’s complex leaving the proximal end of the shunt lying within the extraocular space.

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