Ophthalmic implant with drainage tube flow limiting mechanism for treating glaucoma

Abstract

An ophthalmic implant for treating or alleviating symptoms of glaucoma. The translimbal tube of the implant is restricted to reduce the outflow of aqueous humor. The implant is sterilized together with a flow restrictor on the translimbal tube, thus no longer having any additional requirements for the user prior to use.

Description

Technical Field

[0001] The present application relates to a device and method for setting a flow restriction on a drainage tube of an ophthalmic implant. The implant together with the flow restriction on the drainage tube is sterilized and provided to the user so as to be used for the patient at any time. Background Art

[0002] Glaucoma is a term that refers to a group of eye diseases that gradually destroy vision. Vision loss due to glaucoma is caused by damage to the optic nerve. High intraocular pressure (IOP) is a risk factor for glaucoma. Glaucoma can also lead to high intraocular pressure. Therefore, glaucoma implants are designed to reduce intraocular pressure and maintain it at normal levels over the long term.

[0003] The glaucoma implant of the present invention is a further development and improvement of the glaucoma implant that was the subject of a previous patent by the same inventor.

[0004] US4,457,757 describes an implant that is inserted into the outer tissue layer (Tenon's tissue) in the eye. The implant comprises a plate attached to the surface of the eyeball and a tube extending from the plate and inserted into the anterior chamber of the eye. This enables aqueous humor to be transferred from the anterior chamber to the plate through the tube, where the fluid is absorbed into the surrounding tissue. This reduces the intraocular pressure (IOP).

[0005] A problem associated with these implants is an excessive decrease in intraocular pressure (IOP) after implantation (postoperative hypotony). This can damage the eye and lead to impaired vision.

[0006] US4,750,901 describes an improved implant that is intended to prevent postoperative hypotony. The implant has two raised ridges on the upper surface of the plate. A ridge surrounds the edge of the plate or is close to the edge to help define and maintain a bubble into which the fluid from the eye can be drained and absorbed into the overlying Tenon tissue. The attached ridge defines a smaller second zone within the region defined by the peripheral edge of the plate. During implantation, the Tenon tissue is pulled forward and stretched to cover the attached ridge of the plate of the implant and is securely sutured to the sclera just in front of the plate. This builds a chamber into which the fluid from the anterior chamber of the eye is drained. The tension applied by the tissue to the attached ridge makes it possible for the fluid to leak out of the plate outside the attached ridge only when the pressure reaches a certain level. This reduces the possibility that the fluid from the eye is too easily absorbed into the Tenon tissue covering the plate in the first few days after surgery, and causes an undesirable excessive reduction in intraocular pressure (IOP).

[0007] The plates of the implant described in US4,750,901 may be connected to one or more other plates by interconnected tubes to allow fluid to flow from the first (main) plate to the auxiliary plate. This provides a larger surface area to more effectively disperse large amounts of aqueous humor. However, implanting multiple plates and tube configurations greatly increases the complexity and difficulty of surgical implantation. The auxiliary ridge principle described in US4,750,901 can be applied to any auxiliary plate.

[0008] Other glaucoma implants are known, but these have problems or disadvantages.

[0009] US5,178,604 (Baerveldt) describes an implant made of an elastomeric material in order to avoid the trauma to the eye that might be caused by using an implant made of a rigid material. However, for the present application, the inventors have never observed such trauma or irritation. Baerveldt claims that softer materials are easier to insert into the Tenon's capsule. However, US6,261,256 (Ahmed) suggests that the opposite may be true.

[0010] US5,300,020 (L'Esperance, Jr.) describes an implant, i.e., a screw designed to hold a channel open to drain the aqueous humor from the eye. However, this implant ignores the need for a plate to be attached to the tubular channel to prevent fibrous tissue from covering the end of the channel and preventing fluid from leaking out.

[0011] US 5,370,607 (Memmen) describes a flexible belt and reservoir / tube design with baffles on the surface to direct fluid flow.

[0012] US5,397,300 (Baerveldt) describes the use of one or more holes in the plate of the implant described in US5,178,604. The purpose of the holes is to provide tethering of fibrous tissue to prevent the bleb from over-expanding, interfering with the action of the eye muscles and causing double vision (diplopia).

[0013] US5,454,796 (Krupin) describes an implant comprising a tube and a valve within the tube. However, as with all valve designs, there is a risk of clogging by blood clots or debris commonly found in glaucoma fluid.

[0014] US5,476,445 (Baerveldt) describes a temporary flow-restricting seal beneath the plate of an implant. The implant is designed to provide a temporary, non-valved flow-restricting device intended to eliminate postoperative hypotonia. The walls of the implant form a seal beneath the plate, between the plate and the sclera, into which the fluid drains. The fluid does not escape until the pressure buildup in the eye exceeds the pressure that the sutures holding the plate down on the sclera can withstand. The sutures are temporary and dissolvable. They anchor the plate to the sclera immediately after surgery, thereby preventing postoperative hypotonia. The sutures then dissolve, leaving the plate anchored only by the downward pressure of the Tenon's tissue. This reduces the pressure required to affect the release of fluid from the anterior chamber. However, the placement of these sutures requires considerable additional surgical time. There is also a risk of fibrous tissue ingrowth into the cavity closest to where the tube enters the eye.

[0015] US5,558,629 (Baerveldt) describes an implant similar to the implant of US5,178,604 and additional features, including a radiopaque plate, an absorbable ligature around the tube of the implant, an absorbable plug to limit the leakage of aqueous humor immediately after surgery, a double lumen tube, and two parallel tubes. This implant will suffer from the same problems as the implant discussed in above-mentioned US5,476,445.

[0016] US5,616,118 (Ahmed) describes an implant with a diaphragm valve system. The valve opens and closes according to the intraocular pressure. Like all valved systems, it runs the risk of becoming blocked by blood clots or fibrin, which may require further surgery or removal of the implant. US5,681,275 (Ahmed) describes a double plate version, while US5,785,674 (Ahmed) describes a winged version intended to prevent squinting.

[0017] US6,261,256 (Ahmed) describes an implant with ridges on the plate surface to prevent it from rolling up during insertion. In practice, however, creating multiple bubbles through holes in the ridges to provide anchoring of fibrous tissue will reduce the effectiveness of the device and lead to higher intraocular pressure in the long term.

[0018] US6,468,283 (Richter) describes an implant of screw design. The implant has a small disk with ridges at the outer end, which is intended to prevent fibrous tissue blockage. In practice, this disk is too small in most cases, and a fibrous tissue cap will form on this disk, preventing drainage.

[0019] Therefore, there is a need for further improvements in implants. In particular, there is a need to provide a larger drainage area on a single plate to allow for effective dispersion of aqueous humor while minimizing the complexity of surgical implantation. In addition, to further assist in inserting the implant into the Tenon's capsule, a lower profile implant is needed. There is also a need to improve the contact between the accessory ridge and the overlying Tenon's tissue so as to increase the pressure of the fluid to lift the tissue away from the accessory ridge and drain to a larger area of ​​the plate. This will improve the ability of the implant to prevent postoperative hypotonia.

[0020] Once the implant is in place, the drain is usually restricted. This is to prevent conjunctival adhesion and the development of a vascular capsule after 4-6 weeks. When the vascular capsule is formed, the aqueous humor can flow freely. Some implants do not restrict the drain. If the drain is not restricted, it can lead to early postoperative hypotony, flattening of the anterior chamber, scarring, and choroidal effusion.

[0021] The surgeon may restrict the drainage tube of the implant prior to use, and the drainage tube is usually restricted by sutures around the drainage tube system. The sutures used may be non-degradable or degradable sutures. The benefit of using degradable sutures is that over time, the sutures degrade, which once broken, allows the aqueous humor to flow freely. The duration of suture degradation is similar to the time it takes for the vascular overlying fibrous capsule to form on the implant, which is 4-6 weeks. Therefore, once the vascular overlying fibrous capsule is formed, the restriction of the suture to the drainage tube can be completely absorbed, allowing the outflowing aqueous humor to flow freely.

[0022] Alternatively, a two-stage insertion may be performed, where the device is sutured in its equatorial position but not connected to the anterior chamber. Once the fiber chamber is formed, the tube is only inserted into the anterior chamber. Between each stage, medication or orphan trabeculectomy is used to control intraocular pressure (IOP).

[0023] Valves have also been used as a form of restriction in drains, although studies have shown that valves increase the overall resistance to aqueous humor flow and may become obstructed in the presence of severe anterior chamber inflammation and fibrin formation. Valves are also designed to be made of biodegradable materials that degrade after 6 weeks, which occurs during the hypertensive phase of device encapsulation. This matches the duration of the biodegradable sutures on drains.

[0024] Another problem is that when surgeons use and apply sutures, the force with which they apply the restriction is not always consistent. This can lead to problems with too much or too little aqueous humor outflow.

[0025] It is therefore an object of the present invention to provide an implant for alleviating the problems associated with glaucoma which avoids, at least to some extent, the problems associated with known implants or which at least provides a useful alternative to known implants. Summary of the invention

[0026] In a first aspect, the present invention provides an ophthalmic implant comprising a translimbal tube, wherein a flow restriction is arranged on the translimbal tube to reduce the outflow of aqueous humor. The implant and the flow restriction are packaged and sterilized together, so that the end user does not need to perform any work or adjustment.

[0027] Preferably, the flow restrictor is a knot made from suture disposed around the translimbal tube.

[0028] Preferably, the flow restrictor is in the form of a band surrounding the translimbal tube.

[0029] Preferably, the flow restrictor is in the form of a clip surrounding the translimbal tube.

[0030] Preferably, the flow restrictor is in the form of a cable tie surrounding the translimbal tube.

[0031] Preferably, these flow restrictors utilize a degradable material that can be absorbed by the patient.

[0032] Another aspect of the present invention provides an ophthalmic implant for treating or alleviating the symptoms of glaucoma, the implant comprising:

[0033] a plate shaped to conform to a surface portion of an eye when implanted, an inner ridge located on an upper convex surface of the plate, wherein an area surrounded by the inner ridge defines a primary drainage zone into which a fluid stream may be drawn from an anterior chamber or a posterior chamber of the eye, in use;

[0034] a secondary drainage region outside the inner ridge into which fluid from the primary drainage region can be received in use;

[0035] an aperture in the inner ridge, the aperture being sized to allow a drainage tube for draining fluid from the anterior chamber or posterior chamber of the eye to the primary drainage area to be connected thereto so that fluid can be transferred through the tube to the primary drainage area, the secondary drainage area being defined by the inner ridge and an edge of the plate or an outer ridge located on an upper convex surface of the plate, wherein the height of the inner ridge relative to the surface of the plate is greater than the height of the outer ridge relative to the surface of the plate; and

[0036] The drainage tube includes a fluid flow restriction device.

[0037] It should be noted that any one of the aspects mentioned above may include any features of any other aspect mentioned above, and if appropriate may include any features of any embodiment described below.

[0038] The object of the present invention is to provide a system and method to solve the above-mentioned deficiencies, or at least provide the public with a useful alternative. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The preferred features, embodiments and variations of the present invention can be discerned from the following detailed description, which provides sufficient information for those skilled in the art to implement the present invention. The detailed description should not be construed as limiting the scope of the foregoing invention in any way. The detailed description will refer to the following several drawings.

[0040] Figure 1 is a perspective view of an eye with an implant of the present invention inserted therein;

[0041] Figure 2 is a side cross-sectional view of an eye having an implant of the present invention inserted therein;

[0042] Figure 3 is a front cross-sectional view of a portion of the wall of the eyeball into which the implant of the present invention is inserted;

[0043] Figure 4 is a perspective view of an implant of the present invention;

[0044] Figure 5 is a perspective view of the translimbal tube with knot;

[0045] Figure 6 is a perspective view of the translimbal tube with straps. DETAILED DESCRIPTION

[0046] The implant of the present invention comprises a plate and tube assembly of the type described in US 4,457,757. Intraocular pressure (IOP) is reduced by transferring aqueous humor from the inside of the eyeball to the plate via the tube. The fluid transferred to the plate is absorbed into the surrounding tissue. Preferably, the tube is inserted through the sclera into the anterior chamber or posterior chamber of the eye, thereby providing fluid communication between the inside of the eye and the surface of the plate.

[0047] The present invention also utilizes the ridge mechanism described in US 4,750,901 to prevent postoperative hypotony. The ridge mechanism includes an inner ridge that defines a portion of the plate surface area and an outer ridge located at or near the edge of the plate. However, the ridge mechanism of US 4,750,901 is improved in the present invention by providing an improved connection between the inner ridge and the overlying Tenon's tissue.

[0048] Preferred implants of the present invention have enlarged plates relative to some other implants. This provides a larger fluid dispersion area. Thus reducing the need for multiple plate implants and avoiding surgical problems associated with multiple plate insertions.

[0049] Preferred implants of the present invention have no outer ridges or have low profile outer ridges at or near the edges of the plate. It has been found that the outer ridges are not necessary to maintain the air bubble on the plate. The reduced outer ridges reduce the profile of the implant, making it easier to insert into the Tenon's capsule.

[0050] The enlarged plate of the implant of the present invention, together with the lower outer ridge, also helps to improve the contact between the inner ridge and the overlying Tenon's tissue. The increased width of the plate allows the implant to be positioned so that at least a portion of each of the two opposing sides of the plate is located below the rectus muscle insertion end. The Tenon's tissue adjacent to the rectus muscle insertion end is strengthened by the expansion of fibers extending from the rectus sheath to the Tenon's tissue. This allows the Tenon's tissue to be pulled tighter over the inner ridge during implantation. Therefore, the hydraulic pressure required to lift the Tenon's tissue away from the inner ridge to allow fluid to be drained from the area surrounded by the inner ridge (primary drainage area) to the larger area of ​​the plate outside the inner ridge (secondary drainage area) is increased, and the ability of the implant to prevent postoperative hypotonia is thereby improved.

[0051] Enzymes produced by the tissue covering the implant are used to clear blood clots or inflammatory exudates that can cause blockage of valve-based implants, screw implants, or implants where drains are located below the plate. In addition, any blockage caused by blood clots or inflammatory exudates will be quickly cleared by enzymes from the overlying tissue. This is in contrast to implants with mechanical valves, such as the implant invented by Krupin and Ahmed, where blockages may require repeat surgery or removal of the implant.

[0052] The implant of the present invention can be made of any biocompatible material, whether rigid or flexible. Preferably, the implant is made of polypropylene. In a preferred embodiment, the implant has great flexibility due to its thinness and lack of obvious external ridges.

[0053] The plate of the implant is curved to accommodate the curvature of the eyeball. Preferably, the plate has holes near its edge that allow sutures to pass through the plate so that the plate is attached to the surface of the eyeball. In a preferred embodiment, the plate has four suture holes.

[0054] The plate is attached to the surface of the eyeball beneath the outer tissue layer, known as Tenon's tissue. During surgery, the plate is inserted between the sclera and Tenon's capsule and sutured to the surface of the eyeball (sclera).

[0055] The implant can be positioned in any of the four quadrants of the eye, with the superior temporal and superior nasal quadrants being the most commonly used.

[0056] Preferably, the plate is positioned so that it is located between the tendon insertions of two adjacent rectus muscles on the surface of the eyeball. The plate is held in place by the normal muscle tone of the adjacent rectus muscles and by sutures passing through the anterior suture holes of the plate and the tendon insertions of the rectus muscles.

[0057] The size of the implant can vary. Preferably, however, the width of the plate is such that the sides of the plate can be partially inserted under the adjacent rectus muscles. Preferably, the length of the plate is such that it avoids the optic nerve and blood vessels at the back of the eye. In a preferred embodiment, the plate is designed to fit between two adjacent rectus muscles and slightly below the edge of each of the rectus muscles.

[0058] The plates of the implant may be connected to one or more other plates by interconnected tubes to allow fluid to flow from the first (primary) plate to the auxiliary plates. However, in a preferred embodiment of the invention, the implant has plates with sufficiently large surface areas to eliminate the need for multiple plate implants in most cases.

[0059] The surface of the plate may have low profile outer ridges or may be free of outer ridges. Applicants have found that a distinct outer ridge is not necessary for forming and maintaining a bubble. In a preferred embodiment, the size of the outer ridge is significantly reduced relative to the outer ridge described in US 4,750,901. Reduction or removal of the outer ridge provides an implant with a reduced profile that is therefore easier to insert into the Tenon capsule.

[0060] As mentioned above, a problem associated with this type of implant is an excessive decrease in intraocular pressure (IOP) after implantation (postoperative hypotony). This can lead to damage to the eye, which can affect vision.

[0061] The present invention avoids this problem by utilizing the ridge mechanism described in US 4,750,901. However, the present invention improves upon the ridge mechanism in US 4,750,901 by providing an improved connection between the inner ridges and the overlying Tenon tissue.

[0062] An internal ridge merges the opening of the tube into the upper surface of the plate.

[0063] The size of the area defined by the inner ridges (the primary drainage area) can vary from an area large enough to incorporate the openings through which the tubes blend into the plate surface, to an area that occupies a large portion of the plate. However, the larger the primary drainage area, the lower the pressure at which fluid can flow into the secondary drainage area. In a preferred embodiment, the primary drainage area occupies less than one quarter of the plate surface area.

[0064] The implant may have additional ridges, wherein each additional ridge defines a further ridged region at a different location on the plate surface.The ridge principles of the present invention may also be applied to any accessory plate configuration.

[0065] During implantation, the Tenon tissue is stretched forward to cover the inner ridge of the plate of the implant and securely sutured to the sclera just in front of the plate. This creates a chamber into which fluid from the anterior or posterior chamber of the eye is drained. The tension exerted by the tissue on the inner ridge enables fluid to flow out to the plate outside the inner ridge and into the secondary drainage area only when pressure reaches a certain level.

[0066] As fluid begins to flow through the tubes of the implant, the Tenon's tissue stretched over the inner ridge of the implant provides sufficient resistance to prevent fluid from flowing out of the eye, thereby limiting fluid drainage to the primary drainage area. This reduces the likelihood that fluid from the eye will be too easily absorbed by the Tenon's tissue covering the larger area of ​​the entire plate during the first few days after surgery, and thus avoids postoperative hypotonia. When the intraocular pressure (IOP) rises to a level sufficient to lift the Tenon's tissue off the inner ridge, drainage through the entire area of ​​Tenon's tissue covering the plate of the implant begins and the intraocular pressure gradually decreases. If the intraocular pressure drops below the above level, the Tenon's tissue returns to contact the inner ridge to reduce or prevent fluid from flowing into the secondary drainage area. In this way, the inner ridge in combination with the Tenon's tissue acts as a valve.

[0067] The thickness of Tenon's tissue varies. It is greatest between the equator of the eye and the muscle-tendon attachments. In a preferred embodiment of the invention, it is this thicker portion of the Tenon's tissue that is stretched over the inner ridge of the implant during surgery. The manipulation of the tissue during surgery, along with the pro-inflammatory effects of the fluid on the tissue, raises the pressure within the Tenon's tissue to about 12 to 15 mmHg. Preferably, the intraocular pressure (IOP) must be greater than about 12 to 15 mmHg before the Tenon's tissue is lifted off the inner ridge of the implant to allow fluid to flow into the secondary drainage area.

[0068] Where appropriate, an absorbable ligature may be used with or without delay to delay the drainage of fluid.

[0069] Now only refer to the attached drawings Figures 1 to 4 The present invention is further described by way of examples.

[0070] Figure 1 The implant 1 of the present invention is shown attached to the surface of the eyeball by sutures 2 which pass through holes positioned near the edge of an implant plate 3. The plate 3 is positioned between the tendon attachments 4 of two rectus muscles so that a portion of each of the two opposing sides of the plate 3 is located below the rectus muscle attachments.

[0071] The plate 3 is curved to adapt to the curvature of the eye and to enable the plate 3 to be neatly placed on the surface of the eye.

[0072] An elliptical inner ridge 5 extends from the upper (convex) surface of the plate 3 at the front edge of the plate 3 (relative to the eye). The inner ridge 5 forms a primary drainage area 6 on the upper surface of the plate 3.

[0073] A translimbal tube 7 extends from region 6 through the limbal tissue into the anterior chamber 8 of the eye. Figure 2 The translimbal tube 7 enables fluid to be transferred from the anterior chamber 8 of the eye to the zone 6, thereby reducing the pressure in the anterior chamber 8.

[0074] like Figure 2 As shown, the implant 1 is located on the upper surface of the eye below the outer tissue layer of the eyeball (Tenon's capsule 9). The rectus muscle 10 is in contact with the eyeball from the equator of the eyeball to the point where the rectus muscle 10 is anchored on the anterior surface of the eyeball (rectus tendon attachment end 4). The posterior Tenon's tissue is relatively thin. However, the anterior Tenon's tissue is thicker due to the enhancement of the expansion of the fibers extending from the rectus sheath. This enhanced thicker anterior portion of the Tenon's tissue 11 covers the area 6 and is maintained in contact with the inner ridge 5 and stretched over the inner ridge by the natural muscle tension of the adjacent rectus muscles 4. This helps to maintain contact between the inner ridge 5 and the overlying tissue 11.

[0075] Figure 2 It is further shown that Tenon's tissue forms a layer over zone 6 on the upper surface of plate 3, thereby defining chamber 12. Chamber 12 is capable of containing fluid transferred through tube 7 from the anterior chamber 8 of the eye.

[0076] Figure 3 The chamber 12 is further illustrated. Figure 3 It is also illustrated that the sides of the plate 3 are immediately followed by the rectus tendon attachment 4 and the Tenon's tissue, which forms a layer on the inner ridge 5 that is thickened by the expansion of the fibers of the rectus sheath and is maintained in contact with the inner ridge 5 by muscle tension.

[0077] Figure 4 A circular plate 3 is shown with curved front and rear ends but relatively straight sides, and the plate comprises four holes 14 located near the edge of the plate 3. These holes 14 allow the plate 3 to be sutured to the surface of the eyeball.

[0078] The inner ridge 5 extends from the surface of the plate 3 near the front end 17 of the plate 3. The portion of the inner ridge 5 closest to the outer edge of the plate 3 has a hole 15. When the implant 1 is surgically implanted, the tube ( Figure 4 The end of the implant plate 3 (not shown) fits tightly into the hole 15 from the outside of the inner ridge 5 and leads to the anterior chamber of the eye. The outer ridge 16 is located at the edge of the implant plate 3 and merges with the ridge 5 at the front end 17 of the plate 3.

[0079] Thus, the present invention provides an implant that provides a larger fluid dispersion area, a lower profile for ease of implantation, and improved contact between the inner ridge and the overlying Tenon's tissue within a single plate and tube arrangement. Thus, the implant of the present invention improves the ability of the implant to prevent postoperative hypotonia. The plate together with the living tissue overlying it forms a biological tissue / plate valve, which regulates the outflow of intraocular fluid in the early postoperative period. Unlike valve-based implants, screw implants, or implants where the drainage tube is located below the plate and becomes clogged with blood clots or inflammatory exudates, this biological valve system ensures that the drainage system will not become clogged with blood clots or inflammatory exudates.

[0080] A tie 30 may be provided around the translimbal tube 7 to control intraocular pressure (IOP) and reduce the flow of aqueous humor. The tie 30 may be in the form of, but not limited to, a knot 41, a band 42, a partially closed valve, a clip, a cable tie, and an insertion tube. It is preferred to use a knot 41 made of a suture 43 around the translimbal tube 7.

[0081] The fluid flow control mechanism may include a biodegradable material that completely or partially occludes the drainage tube.

[0082] The drainage restrictor can be made of a drug eluting material that can elute active drug ingredients, such as common anti-inflammatory drugs (salicylates, prostaglandin antagonists, leukotriene antagonists, polyphenols and vasoconstrictors), intraocular pressure-reducing drugs used after GDD implantation (topical β-adrenergic antagonists, carbonic anhydrase inhibitors, cholinergics, α-adrenergic agonists, prostaglandins or corticosteroids, (such as dexamethasone, hydrocortisone, methylprednisolone and prednisone).

[0083] There is no limitation on the number of tie-downs 30 used on the translimbal tube 7 , and the preferred range is 1-3 tie-downs 30 .

[0084] The tether 30 serves to reduce drainage from the anterior chamber 8 through the translimbal tube 7 .

[0085] The knot 41 restricts 30 the fluid flow in the translimbal tube 7 by tightening around the outer surface of the translimbal tube 7 and reducing the inner diameter of the translimbal inner opening 31. As the inner diameter decreases, the fluid flow from the anterior chamber 8 through the translimbal tube 7 is reduced. The translimbal tube 7 of the implant 1 has an outer diameter of not limited to 0.63 mm and an inner diameter of 0.30 mm. After tying the knot 41, the inner diameter 31 of the translimbal tube 7 can be between 0.01 and 29 mm, but is not limited to this range.

[0086] The knot 41 is usually tied with a suture 43, the type of which may be, but is not limited to, 6-0 polypropylene suture, 5-0 coated Vickers suture, and monofilament polyhexene 25 suture. Other types of suture materials may also be used, such as, but not limited to, suture (Monocryl), absorbable surgical suture (Caprosyn), needled suture (Vicryl), absorbable synthetic suture (Polysorb), absorbable suture (Dexon), PDS, Biosyn, polyglycol carbonate suture (Maxon), and nylon.

[0087] The preferred material for the knot 41 restrictor can be, but is not limited to, polypropylene. The benefit of this material is that it can be autoclaved, gamma sterilized, ethylene oxide sterilized, and various sterilization methods, depending on the survival rate of the selected material with the implant. The benefit of sterilizing the implant 1 and the knot 18 at the same time is to ensure that the device can be used without further sterilization. Sterilization can be performed in the final packaging that the user will receive, so once the user receives the implant 1, the user does not need to perform further sterilization.

[0088] The type of knot 41 used may be, but is not limited to, a square knot, a clove knot, a constriction knot, a ligature, a surgical knot, a granny knot, or a surgeon's knot.

[0089] The flow rate of the junction 41 can be tested by injecting saline by fitting a syringe snugly over the translimbal tube 7 and applying pressure with saline solution.

[0090] The tensile strength of polycaprolactone sutures decreases over time. For example, but not limited to, polycaprolactone sutures lose 50-60% of their original tensile strength after 7 days, lose 20-30% of their original tensile strength after 14 days, and are absorbed after 90-120 days. This provides a time-varying flow rate for the aqueous humor in the translimbal tube 7. As the suture 43 slowly dissolves over time, the tensile strength of the knot 41 on the translimbal tube 7 decreases, which allows the inner diameter 31 of the translimbal tube 7 to increase back to its original size and allows the aqueous humor to flow freely.

[0091] When the suture 43 is completely dissolved, the translimbal tube 7 can flow freely, allowing the intraocular pressure (IOP) to return to normal. If a non-dissolvable suture 43 is used, it needs to be removed after a selected period of time.

[0092] The pressure of the knot 41 on the translimbal tube 7 can be varied to change the inner diameter of the translimbal tube 7. The pressure of the knot 41 on the translimbal tube 7 can range from 1 to 200 mmHg, but is not limited to this range. To achieve the change in pressure, the knot 41 will be placed around the translimbal tube 7 and tightened by pulling the knot end 42 until the desired tension is reached. This pressure can be measured by a strain gauge on the device that pulls the knot end 42.

[0093] After the knot 41 is placed around the translimbal tube 7, the knot end 42 is trimmed off, leaving but not limited to 2-3 mm of suture.

[0094] The knot 41 may be applied to the translimbal tube 7 by manual or mechanical means, but is not limited thereto. A machine or mechanical means is used to tie the knot 41 around the translimbal tube 7, ensuring that the desired amount of torque is achieved on the knot 41. The machine or mechanical means used to tie the knot 41 can ensure that a consistent amount of torque is achieved.

[0095] The translimbal tube 7 may also be constrained by placing a band 45 around the translimbal tube 7. The band 45 is placed over the translimbal tube 7, squeezing the tube 7 and reducing the inner diameter, thereby reducing the potential outflow of aqueous humor.

[0096] The location of the flow restrictor may be located anywhere along the translimbal tube 7. For example, the flow restrictor may be located near the implant 1 or near the end of the translimbal tube 7.

[0097] The means for determining the potential pressure in the translimbal tube 7 may be in the form of a band 45 disposed about the tube that changes color or the distance between known points on the band shifts to a certain degree. For example, as the pressure within the translimbal tube 7 increases, the color of the band 45 may become lighter because the outer surfaces are pulled further apart, making the lighter colored inner surface visible. However, as the pressure decreases, the color may become darker. Additionally, points on the band 45 may be marked, and as the pressure increases, the distance between two points may be measured to determine the internal pressure within the translimbal tube 7.

[0098] Mechanical measures may also be used to restrict the translimbal tube, various forms of mechanical restrictors such as, but not limited to, cable ties or clips. Cable ties (not shown) or clips (not shown) may be in the form of degradable or non-degradable materials.

[0099] A cable tie (not shown) of a set diameter corresponding to the desired reduced flow rate may be placed around the translimbal tube 7 and pulled until it reaches the set point.

[0100] A clamp (not shown) can also be used to reduce flow in the translimbal tube 7. The clamp can have a set diameter corresponding to the desired reduced flow rate. The translimbal tube 7 is placed into the clamp, and the clamp is then secured around the translimbal tube 7 with a clip. When the clamp is closed around the translimbal tube 7, the translimbal tube 7 will be squeezed and the outflow of aqueous humor will be reduced.

[0101] Another measure of restricting the tube may be in the form of another tube (not shown) inserted into the open end of the translimbal tube 7. The restricting tube may have an outer diameter that matches the inner diameter of the translimbal tube 7 and have an inner diameter that restricts the flow to a desired flow rate. The tube may be removed from the end of the translimbal tube 7 and a new tube having the desired inner diameter may be inserted.

[0102] After the tether 30 is placed on the translimbal tube 7, the implant 1 together with the tether 30 is packaged in a container and then sterilized. This allows the implant 1 and tether 30 to be used in a patient without any further modification by the user prior to use.

[0103] The form of sterilization used may be, but is not limited to, autoclaving or gamma irradiation. The user is provided with the implant 1 ready for use in a patient, with the restrictor already in place, thereby preventing any potential contamination that may be introduced. The user can simply open the package and use the implant 1.

[0104] Although the present invention has been described by way of example, it will be appreciated that changes and modifications may be made without departing from the scope of the claims. Furthermore, where known equivalents exist for specific features, these equivalents shall be incorporated as if specifically mentioned in this specification.

[0105] Industrial Applicability

[0106] The ophthalmic implants of the present invention can be used to treat or alleviate the symptoms of glaucoma. After surgical implantation, the implant (with attached drainage tubes) enables fluid to be transferred from within the eye to the upper surface of the implant's plate, and from there the fluid is absorbed into the surrounding tissue. As a result, intraocular pressure is reduced and the effects of glaucoma are mitigated.

[0107] Further optimization and improvement may be made to the present invention without departing from the scope of the present invention. Although the present invention has been shown and described in what are considered to be the most practical and preferred embodiments, it is recognized that modifications may be made within the scope of the invention, and the present invention should not be limited to the details disclosed herein, but should be given a full scope according to the claims to cover all equivalent devices and apparatuses. Any discussion of the prior art throughout the specification should not be regarded as an admission that such prior art is well known or constitutes part of the common knowledge in the field.

[0108] In this specification and claims (if any), the word "comprise" and its derivatives, include every element stated, but do not exclude the inclusion of one or more additional elements.

[0109] Reference numerals list

[0110] 1 Implant

[0111] 2 Sutures

[0112] 3 Implant Plates

[0113] 4 Attachment end

[0114] 5. Inner Rib

[0115] 6 Drainage Area

[0116] 7 Translimbal tube

[0117] 8 Anterior chamber

[0118] 9Tenon capsule

[0119] 10. Rectus muscle

[0120] 11 Overlying tissue

[0121] 12 chambers

[0122] 14 plate holes

[0123] 15 holes

[0124] 16 outer ridge

[0125] 17 Front end of the board

[0126] 30 restraints

[0127] 31 inner mouth

[0128] 41 knot

[0129] 42 Knot

[0130] 43 Suture

[0131] 45 strap

Claims

1. An ophthalmic implant for treating or alleviating the symptoms of glaucoma, the implant comprising: a. a plate shaped to conform to a surface portion of an eye when implanted, an inner ridge located on an upper convex surface of the plate, wherein the area enclosed by the inner ridge defines a primary drainage zone into which, in use, a fluid flow from the anterior chamber or posterior chamber of the eye can be drawn; b. a secondary drainage area outside the inner ridge into which fluid from the primary drainage area can be received during use; c. an aperture in the inner ridge sized to allow a drainage tube for draining fluid from the anterior chamber or posterior chamber of the eye to the primary drainage area to be connected thereto so that fluid can be transferred through the tube to the primary drainage area, the secondary drainage area being defined by the inner ridge and an edge of the plate or an outer ridge located on the upper convex surface of the plate, wherein the height of the inner ridge relative to the surface of the plate is greater than the height of the outer ridge relative to the surface of the plate; and d. The drainage tube includes a fluid flow restriction device.

2. The ophthalmic implant according to claim 1, wherein The fluid flow restriction device blocks the drainage tube.

3. The ophthalmic implant according to claim 1, wherein: The fluid flow restriction device on the drainage tube includes a knot.

4. The knot according to claim 3, wherein The knot is made of degradable suture.

5. The ophthalmic implant of claim 1, wherein: The fluid flow restriction device on the drainage tube includes a band.

6. The belt according to claim 5, wherein: The tape is degradable.

7. The ophthalmic implant of claim 1, wherein: The fluid flow restriction device includes a clip.

8. The belt according to claim 7, wherein: The clip is degradable.

9. The ophthalmic implant of claim 1, wherein: The fluid flow restriction device comprises a cable tie.

10. The cable tie according to claim 9, wherein: The cable tie is degradable.

11. The ophthalmic implant of claim 1, wherein: The ophthalmic implant is autoclaved or sterilized with the fluid flow restriction device attached.

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