METHODS AND DEVICES FOR INCREASING AQUEOUS HUMOR OUTFLOW
An ocular implant having an inlet portion and a Schlemm's canal portion distal to the inlet portion, the inlet portion being disposed at a proximal end of the implant and sized and configured to be placed within an anterior chamber of a human eye, the Schlemm's canal portion being arranged and configured to be disposed within Schlemm's canal of the eye when the inlet portion is disposed in the anterior chamber.
This application claims the benefit under 35 U.S.C. §119 of U.S. Application No. 62/110,293, titled “Methods and Devices for Increasing Aqueous Humor Outflow”, filed Jan. 30, 2015. This application is a continuation-in-part of U.S. application Ser. No. 14/691,267, filed Apr. 20, 2015, and is a continuation-in-part of U.S. application Ser. No. 14/932,658, filed Nov. 4, 2015, the disclosures of which are incorporated by reference as if fully set forth herein.
INCORPORATION BY REFERENCEAll publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.
FIELD OF THE INVENTIONThe present invention relates generally to devices that are implanted within the eye. More particularly, the present invention relates to devices that facilitate the transfer of fluid from within one area of the eye to another area of the eye.
BACKGROUNDAccording to a draft report by The National Eye Institute (NEI) at The United States National Institutes of Health (NIH), glaucoma is now the leading cause of irreversible blindness worldwide and the second leading cause of blindness, behind cataract, in the world. Thus, the NEI draft report concludes, “it is critical that significant emphasis and resources continue to be devoted to determining the pathophysiology and management of this disease.” Glaucoma researchers have found a strong correlation between high intraocular pressure and glaucoma. For this reason, eye care professionals routinely screen patients for glaucoma by measuring intraocular pressure using a device known as a tonometer. Many modern tonometers make this measurement by blowing a sudden puff of air against the outer surface of the eye.
The eye can be conceptualized as a ball filled with fluid. There are two types of fluid inside the eye. The cavity behind the lens is filled with a viscous fluid known as vitreous humor. The cavities in front of the lens are filled with a fluid know as aqueous humor. Whenever a person views an object, he or she is viewing that object through both the vitreous humor and the aqueous humor.
Whenever a person views an object, he or she is also viewing that object through the cornea and the lens of the eye. In order to be transparent, the cornea and the lens can include no blood vessels. Accordingly, no blood flows through the cornea and the lens to provide nutrition to these tissues and to remove wastes from these tissues. Instead, these functions are performed by the aqueous humor. A continuous flow of aqueous humor through the eye provides nutrition to portions of the eye (e.g., the cornea and the lens) that have no blood vessels. This flow of aqueous humor also removes waste from these tissues.
Aqueous humor is produced by an organ known as the ciliary body. The ciliary body includes epithelial cells that continuously secrete aqueous humor. In a healthy eye, a stream of aqueous humor flows out of the anterior chamber of the eye through the trabecular meshwork and into Schlemm's canal as new aqueous humor is secreted by the epithelial cells of the ciliary body. This excess aqueous humor enters the venous blood stream from Schlemm's canal and is carried along with the venous blood leaving the eye.
When the natural drainage mechanisms of the eye stop functioning properly, the pressure inside the eye begins to rise. Researchers have theorized prolonged exposure to high intraocular pressure causes damage to the optic nerve that transmits sensory information from the eye to the brain. This damage to the optic nerve results in loss of peripheral vision. As glaucoma progresses, more and more of the visual field is lost until the patient is completely blind.
In addition to drug treatments, a variety of surgical treatments for glaucoma have been performed. For example, shunts were implanted to direct aqueous humor from the anterior chamber to the extraocular vein (Lee and Scheppens, “Aqueous-venous shunt and intraocular pressure,” Investigative Ophthalmology (February 1966)). Other early glaucoma treatment implants led from the anterior chamber to a sub-conjunctival bleb (e.g., U.S. Pat. No. 4,968,296 and U.S. Pat. No. 5,180,362). Still others were shunts leading from the anterior chamber to a point just inside Schlemm's canal (Spiegel et al., “Schlemm's canal implant: a new method to lower intraocular pressure in patients with POAG?” Ophthalmic Surgery and Lasers (June 1999); U.S. Pat. No. 6,450,984; U.S. Pat. No. 6,450,984). In addition to drug treatments, a variety of surgical treatments for glaucoma have been performed. For example, shunts were implanted to direct aqueous humor from the anterior chamber to the extraocular vein (Lee and Scheppens, “Aqueous-venous shunt and intraocular pressure,” Investigative Ophthalmology (February 1966)). Other early glaucoma treatment implants led from the anterior chamber to a sub-conjunctival bleb (e.g., U.S. Pat. No. 4,968,296 and U.S. Pat. No. 5,180,362). Still others were shunts leading from the anterior chamber to a point just inside Schlemm's canal (Spiegel et al., “Schlemm's canal implant: a new method to lower intraocular pressure in patients with POAG?” Ophthalmic Surgery and Lasers (June 1999); U.S. Pat. No. 6,450,984; U.S. Pat. No. 6,450,984).
SUMMARY OF THE DISCLOSUREThis disclosure pertains to an ocular implant comprising a longitudinally extending body having an inlet portion and a Schlemm's canal portion distal to the inlet portion, the inlet portion being configured to extend into and be in fluid communication with an anterior chamber of a human eye and the Schlemm's canal portion being configured to be inserted into Schlemm's canal adjacent to collector channels of the eye, a plurality of alternating spines and frames positioned longitudinally along at least a portion of the Schlemm's canal portion wherein the plurality of alternating spines and frames define a central channel extending therethrough, with the central channel being in fluid communication with the inlet portion, each of the spines having edges partially defining an opening across from the central channel and in fluid communication with the central channel, and each of the frames including first and second struts, the first and second struts each having an edge contiguous with an edge of an adjacent spine, the edges defining the opening in fluid communication with the central channel, wherein the ocular implant is configured to provide at least a 121% increase in average outflow facility of aqueous humor from the anterior chamber through the collector channels of the eye.
In some embodiments, the implant comprises at least three openings across from the central channel.
In other embodiments, the average outflow facility comprises 0.438 μl/min/mmHg.
In one embodiment, a peak circumferential flow rate through the ocular implant comprises 3.2 μl/min.
In some embodiments, the implant comprises at least six openings across from the central channel.
In one embodiment, the average outflow facility comprises 0.638 μl/min/mmHg.
In some embodiments, a peak circumferential flow rate through the ocular implant comprises 5.7 μl/min.
In one embodiment, the average outflow facility of the eye prior to implantation of the ocular implant comprises 0.138 μl/min/mmHg.
An ocular implant adapted to reside at least partially in a portion of Schlemm's canal of an eye adjacent to collector channels of the eye is provided, the implant comprising a longitudinally extending curved body including a proximal portion and a distal portion, the distal portion of the curved body defining a longitudinal channel including a channel opening, and the curved body being adapted and configured such that the distal portion of the curved body resides in Schlemm's canal and the proximal portion extends into the anterior space of the eye while the ocular implant assumes an orientation in which the channel opening is adjacent a major side of Schlemm's canal when the ocular implant is implanted, wherein the ocular implant is configured to provide a 121%-222% increase in average outflow facility of aqueous humor from the anterior chamber through the collector channels of the eye.
In some embodiments, the implant comprises at least three openings across from the central channel.
In other embodiments, the average outflow facility comprises 0.438 μl/min/mmHg.
In one embodiment, a peak circumferential flow rate through the ocular implant comprises 3.2 μl/min.
In some embodiments, the implant comprises at least six openings across from the central channel.
In one embodiment, the average outflow facility comprises 0.638 μl/min/mmHg.
In some embodiments, a peak circumferential flow rate through the ocular implant comprises 5.7 μl/min.
In one embodiment, the average outflow facility of the eye prior to implantation of the ocular implant comprises 0.138 μl/min/mmHg.
In one embodiment, the distal portion of the curved body occupies up to 20% of Schlemm's canal but accounts for up to 54.5% of total outflow in the eye.
In another embodiment, the distal portion of the curved body occupies up to 40% of Schlemm's canal but accounts for up to 74.6% of total outflow in the eye.
An ocular implant is provided comprising an inlet portion and a Schlemm's canal portion distal to the inlet portion, the inlet portion being disposed at a proximal end of the implant and sized and configured to be placed within an anterior chamber of a human eye, the inlet portion having an inlet adapted to be in fluid communication with the anterior chamber, the Schlemm's canal portion comprising a central channel in fluid communication with the inlet, the central channel extending longitudinally in the Schlemm's canal portion, a first element disposed along the central channel, a second element disposed along the central channel distal to the first element, a third element disposed along the central channel distal to the first element and proximal to the second, a fourth element disposed along the central channel distal to the second element, the first, second, third and fourth elements each comprising two edges partially defining an elongate opening in fluid communication with the central channel, each of the first, second, third and fourth elements having circumferential extents less than 360 degrees so that the elongate opening extends continuously along the first, second, third and fourth elements, the circumferential extents of the first and second elements being less than the circumferential extents of the third and fourth elements, the Schlemm's canal portion being arranged and configured to be disposed within Schlemm's canal of the eye when the inlet portion is disposed in the anterior chamber, wherein the ocular implant is configured to provide a 121%-222% increase in average outflow facility of aqueous humor from the anterior chamber through the collector channels of the eye.
In some embodiments, the implant comprises at least three openings across from the central channel.
In other embodiments, the average outflow facility comprises 0.438 μl/min/mmHg.
In one embodiment, a peak circumferential flow rate through the ocular implant comprises 3.2 μl/min.
In some embodiments, the implant comprises at least six openings across from the central channel.
In one embodiment, the average outflow facility comprises 0.638 μl/min/mmHg.
In some embodiments, a peak circumferential flow rate through the ocular implant comprises 5.7 μl/min.
In one embodiment, the average outflow facility of the eye prior to implantation of the ocular implant comprises 0.138 μl/min/mmHg.
In one embodiment, the distal portion of the curved body occupies up to 20% of Schlemm's canal but accounts for up to 54.5% of total outflow in the eye.
In another embodiment, the distal portion of the curved body occupies up to 40% of Schlemm's canal but accounts for up to 74.6% of total outflow in the eye.
A method of treating glaucoma is provided, comprising supporting tissue forming Schlemm's canal in an eye with an implant extending at least partially in the canal along an axial length within the canal, contacting with the implant less than 50% of the tissue forming the canal along the axial length, disposing an inlet portion of the implant in an anterior chamber of the eye, and providing fluid communication between the anterior chamber and the canal axially through the inlet into a channel of the implant such that an average outflow facility between the anterior chamber and the canal is increased by 121%-222%, and wherein the implant comprises open areas separated by spine areas along a first longitudinal section, the spine areas partially defining the channel, the supporting step comprising orienting the first longitudinal section openings towards a trabecular mesh portion of the canal.
An ocular implant adapted to reside at least partially in a portion of Schlemm's canal of a human eye is provided, the implant comprising a body configured to extend within Schlemm's canal in a curved volume having a large radius side and a short radius side, the body having a circumferential extent within the curved volume that varies along the length of the body between sections having a lesser circumferential extent and sections having a greater circumferential extent, wherein the body defines a channel extending longitudinally through the body, the channel having a substantially open side disposed on the large radius side at one of the sections of lesser circumferential extent and an adjacent section of greater circumferential extent and a plurality of openings along the length of the body on the short radius side, the openings being in fluid communication with the channel, and an inlet portion configured to be disposed in an anterior chamber of the eye when the body is in Schlemm's canal, the inlet portion disposed on a proximal end of the body in fluid communication with the channel, the inlet portion defining one or more openings in fluid communication with the anterior chamber of the eye, wherein the ocular implant is configured to provide a 121%-222% increase in average outflow facility of aqueous humor from the anterior chamber through the collector channels of the eye.
An ocular implant adapted to reside at least partially in a portion of Schlemm's canal of an eye, the eye having an iris defining a pupil is provided, the implant comprising a longitudinally extending curved body including a proximal portion and a distal portion, the distal portion of the curved body having a central longitudinal axis defined by a radius of curvature and a lateral cross section having a first lateral extent and a second lateral extent, an aspect ratio of the first lateral extent to the second lateral extent being greater than or equal to about two, the distal portion of the curved body defining a longitudinal channel including a channel opening, the channel opening included in defining the first lateral extent, the curved body being adapted and configured such that the distal portion of the curved body resides in Schlemm's canal and the proximal portion extends into the anterior space of the eye while the ocular implant assumes an orientation in which the channel opening is adjacent a major side of Schlemm's canal when the ocular implant is implanted, and wherein the ocular implant is configured to provide a 121%-222% increase in average outflow facility of aqueous humor from the anterior chamber through the collector channels of the eye.
The novel features of the invention are set forth with particularity in the claims that follow. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:
Whenever a person views an object, he or she is viewing that object through the cornea, the aqueous humor, and the lens of the eye. In order to be transparent, the cornea and the lens can include no blood vessels. Accordingly, no blood flows through the cornea and the lens to provide nutrition to these tissues and to remove wastes from these tissues. Instead, these functions are performed by the aqueous humor. A continuous flow of aqueous humor through the eye provides nutrition to portions of the eye (e.g., the cornea and the lens) that have no blood vessels. This flow of aqueous humor also removes waste from these tissues.
Aqueous humor is produced by an organ known as the ciliary body. The ciliary body includes epithelial cells that continuously secrete aqueous humor. In a healthy eye, a stream of aqueous humor flows out of the eye as new aqueous humor is secreted by the epithelial cells of the ciliary body. This excess aqueous humor enters the blood stream and is carried away by venous blood leaving the eye.
In a healthy eye, aqueous humor flows out of the anterior chamber 30 through the trabecular meshwork 36 and into Schlemm's canal 38, located at the outer edge of the iris 42. Aqueous humor exits Schlemm's canal 38 by flowing through a number of outlets 40. After leaving Schlemm's canal 38, aqueous humor is absorbed into the venous blood stream.
In
Ocular implant 100 may be inserted into Schlemm's canal of a human eye to facilitate the flow of aqueous humor out of the anterior chamber. This flow may include axial flow along Schlemm's canal, flow from the anterior chamber into Schlemm's canal, and flow leaving Schlemm's canal via outlets communicating with Schlemm's canal. When in place within the eye, ocular implant 100 will support trabecular mesh tissue and Schlemm's canal tissue and will provide for improved communication between the anterior chamber and Schlemm's canal (via the trabecular meshwork) and between pockets or compartments along Schlemm's canal. As shown in
The frames 104 of body 102 include a first frame 136 of ocular implant 100 that is disposed between a first spine 140 and a second spine 142. In the embodiment of
In the embodiment of
In the embodiment of
Stated another way, in the embodiment of
An inner surface 128 of body 102 defines a channel 126. Body 102 of ocular implant 100 includes a first edge 120 and a second edge 123 that define a first opening 124. Channel 126 of ocular implant 100 fluidly communicates with first opening 124. A second opening 138 is defined by a second edge 122A of a first strut 144 and a second edge 122B of a second strut 146. First opening 124, second opening 138 and additional openings defined by ocular implant 100 allow aqueous humor to flow laterally across and/or laterally through ocular implant 100.
As shown in
In the embodiment of
Section lines A-A and B-B are visible in
In
The geometry of the spine provides the ocular implant with flexibility characteristics that may aid in advancing the ocular implant into Schlemm's canal. In the embodiment of
In some useful embodiments, the spine of an ocular implant in accordance with this detailed description has an aspect ratio of width W1 to thickness T1 greater than about 2. In some particularly useful embodiments, the spine of an ocular implant in accordance with this detailed description has an aspect ratio of width W1 to thickness T1 greater than about 4. In one useful embodiment, the ocular implant has a spine with an aspect ratio of width W1 to thickness T1 of about 5.2.
A first axis 156, a second axis 158 and a third axis 160 are shown in
In the embodiment of
In the embodiment of
Each strut shown in
In the embodiment of
In some useful embodiments, the struts of an ocular implant in accordance with this detailed description have an aspect ratio of width W2 to thickness T2 greater than about 2. In some particularly useful embodiments, the struts of an ocular implant in accordance with this detailed description have an aspect ratio of width W2 to thickness T2 greater than about 4. One exemplary ocular implant has struts with an aspect ratio of width W2 to thickness T2 of about 4.4.
Body 102 of ocular implant 100 has a longitudinal radius 150 and a lateral radius 148. In some useful embodiments, an ocular implant in accordance with this detailed description is sufficiently flexible to assume a shape matching the longitudinal curvature of Schlemm's canal when the ocular implant advanced into the eye. Also in some useful embodiments, a length of the ocular implant is selected so that the implant will extend across a pre-selected angular span when the implant is positioned in Schlemm's canal. Examples of pre-selected angular spans that may be suitable in some applications include 60°, 90°, 150° and 180°. The diameter of an ocular implant in accordance with this detailed description may be selected so that the ocular implant is dimensioned to lie within and support Schlemm's canal. In some useful embodiments, the diameter of the ocular implant ranges between about 0.005 inches and about 0.04 inches. In some particularly useful embodiments, the diameter of the ocular implant ranges between about 0.005 inches and about 0.02 inches.
It is to be appreciated that an ocular implant in accordance with the present detailed description may be straight or curved. If the ocular implant is curved, it may have a substantially uniform longitudinal radius throughout its length, or the longitudinal radius of the ocular implant may vary along its length.
In the embodiment of
Ocular implant 200 may be used in conjunction with a method of treating the eye of a human patient for a disease and/or disorder (e.g., glaucoma). Some such methods may include the step of inserting a core member into a lumen defined by ocular implant 200. The core member may comprise, for example, a wire or tube. The distal end of the ocular implant may be inserted into Schlemm's canal. The ocular implant and the core member may then be advanced into Schlemm's canal until the ocular implant has reached a desired position. In some embodiments, an inlet portion of the implant may be disposed in the anterior chamber of eye while the remainder of the implant extends through the trabecular mesh into Schlemm's canal. The core member may then be withdrawn from the ocular implant, leaving the implant in place to support tissue forming Schlemm's canal. Further details of ocular implant delivery systems may be found in U.S. application Ser. No. 11/943,289, filed Nov. 20, 2007, now U.S. Pat. No. 8,512,404, the disclosure of which is incorporated herein by reference.
The flexibility and bending modulus features of the ocular implant of this invention help ensure proper orientation of the implant within Schlemm's canal.
Ocular implant 300 comprises a body 302. With reference to
An inner surface 328 of body 302 defines a channel 326. Body 302 of ocular implant 300 includes a first edge 320 and a second edge 322 that define a first opening 324. Channel 326 of ocular implant 300 fluidly communicates with first opening 324. First strut 344 of first frame 336 comprises a first edge 325A. Second strut 346 has a first edge 325B. In
A first axis 356, a second axis 358 and a third axis 360 are shown in
Many of the figures illustrating embodiments of the invention show only portions of the ocular implant. It should be understood that many embodiments of the invention include an inlet portion (such as inlet 101 in
During the procedure illustrated in
In the embodiment of
Whenever a person views an object, he or she is viewing that object through the cornea, the aqueous humor, and the lens of the eye. In order to be transparent, the cornea and the lens can include no blood vessels. Accordingly, no blood flows through the cornea and the lens to provide nutrition to these tissues and to remove wastes from these tissues. Instead, these functions are performed by the aqueous humor. A continuous flow of aqueous humor through the eye provides nutrition to portions of the eye (e.g., the cornea and the lens) that have no blood vessels. This flow of aqueous humor also removes waste from these tissues.
Aqueous humor is produced by an organ known as the ciliary body. The ciliary body includes epithelial cells that continuously secrete aqueous humor. In a healthy eye, a stream of aqueous humor flows out of the eye as new aqueous humor is secreted by the epithelial cells of the ciliary body. This excess aqueous humor enters the blood stream and is carried away by venous blood leaving the eye.
Schlemm's canal SC is a tube-like structure that encircles iris 1230. Two laterally cut ends of Schlemm's canal SC are visible in the cross-sectional view of
The shape of Schlemm's canal SC is somewhat irregular, and can vary from patient to patient. The shape of Schlemm's canal SC may be conceptualized as a cylindrical-tube that has been partially flattened. With reference to
Schlemm's canal SC forms a ring around iris 1230 with pupil 1232 disposed in the center of that ring. With reference to
The length of major axis 1260 and minor axis 1262 can vary from patient to patient. The length of minor axis 1262 is between one and thirty micrometers in most patients. The length of major axis 1260 is between one hundred and fifty micrometers and three hundred and fifty micrometers in most patients.
With reference to
Body 12128 of ocular implant 12126 has a first major surface 12130 and a second major surface 12132. With reference to
A distal portion of body 12128 defines a longitudinal channel 12138 including a channel opening 12139. Channel opening 12139 is disposed diametrically opposite a central portion 12135 of concave surface 12136. Because of the curvature of the body 12128, an outer diameter of the implant defined by the channel opening 12139 will be greater than an inner diameter of the implant defined by surface 12132. In some embodiments, the body is pre-biased to assume a configuration in which the channel opening 12139 is disposed along an outer diameter of the body, ensuring that the channel opening can be positioned adjacent to the first major side 1250 of Schlemm's canal.
In the embodiment of
Schlemm's canal SC forms a ring around iris 1230 with pupil 1232 disposed in the center of that ring. Schlemm's canal SC has a first major side 1250, a second major side 1252, a first minor side 1254, and a second minor side 1256. With reference to
In the embodiment of
A distal portion of ocular implant 12126 defines a longitudinal channel 12138 including a channel opening 12139. Channel opening 12139 is disposed diametrically opposite a central portion 12135 of first major surface 12130. In the embodiment of
Ocular implant 12126 of
A distal portion of body 12128 defines a longitudinal channel 12138 including a channel opening 12139. Channel opening 12139 is disposed diametrically opposite a central portion 12135 of concave surface 12136. In the embodiment of
As shown in
For purposes of illustration, a window 1270 is cut through first major side 1250 of Schlemm's canal SC in
In the embodiment of
In the embodiment of
With reference to
Body 12128 of ocular implant 12126 defines a plurality of openings 12140. In the embodiment of
A push tube 12180 is visible in
Methods in accordance with the present invention can be used to deliver an implant into Schlemm's canal of an eye. In these methods, a distal portion of core 12166 and sheath 12120 may be advanced out of the distal port of cannula 12102 and into Schlemm's canal. Ocular implant 12126 may be disposed inside sheath 12120 while the distal portion of the sheath 12120 is advanced into Schlemm's canal. Sheath 12120 and core 12166 may then be retracted while push tube 12180 prevents implant 12126 from being pulled proximally.
In the embodiment of
With reference to the Figures described above, it will be appreciated that methods in accordance with the present detailed description may be used to position a distal portion of an implant in Schlemm's canal of an eye. A method in accordance with the present detailed description may include the step of advancing a distal end of a cannula through a cornea of the eye so that a distal portion of the cannula is disposed in the anterior chamber of the eye. The cannula may be used to access Schlemm's canal, for example, by piercing the wall of Schlemm's canal with a distal portion of the cannula. A distal portion of a sheath may be advanced out of a distal port of the cannula and into Schlemm's canal. An ocular implant may be disposed inside the sheath while the distal portion of the sheath is advanced into Schlemm's canal.
In some useful methods, the ocular implant comprises a body defining a plurality of apertures and the method includes the step of covering the apertures with a sheath. When this is the case, the distal portion of the implant may be advanced into Schlemm's canal while the apertures are covered by the sheath. Covering the apertures as the implant is advanced into Schlemm's canal may reduce the trauma inflicted on Schlemm's canal by the procedure. The apertures may be uncovered, for example, after the implant has reached a desired location (e.g., inside Schlemm's canal).
The apertures of the implant may be uncovered, for example, by moving the sheath in a proximal direction relative to the implant. In some applications, this may be accomplished by applying a proximal directed force to the sheath while holding the implant stationary. The implant may be held stationary, for example, by applying a distally directed reaction force on the implant. In one embodiment, a distally directed reaction force is provided by pushing on a proximal end of the implant with a push tube.
Some methods include the step of ceasing advancement of the sheath into Schlemm's canal when a proximal portion of the implant remains in an anterior chamber of the eye and a distal portion of the implant lies in Schlemm's canal. When this is the case, only a distal portion of the implant is advanced into Schlemm's canal. The portion of the implant extending out of Schlemm's canal and into the anterior chamber may provide a path for fluid flow between the anterior chamber and Schlemm's canal.
An assembly may be created by placing a core in a channel defined by the ocular implant. A sheath may be placed around the implant and the core. For example, the core and the implant may then be inserted into the lumen of a sheath. By way of another example, the sheath may be slipped over the implant and the core. The core may be withdrawn from the channel defined by the ocular implant, for example, after the implant has been delivered to a desired location.
The core may be withdrawn from the channel, for example, by moving the core in a proximal direction relative to the implant. In some applications, this may be accomplished by applying a proximal directed force to the core while holding the implant stationary. The implant may be held stationary, for example, by applying a distally directed reaction force on the implant. In one embodiment, a distally directed reaction force is provided by pushing on a proximal end of the implant with a push tube.
The core, the implant, and the sheath may be advanced into Schlemm's canal together. Once the implant is in a desired location, the core and the sheath may be withdrawn from the Schlemm's canal leaving the implant in the desired location. In some methods, the core and the sheath are withdrawn from Schlemm's canal simultaneously.
In the embodiment of
In the embodiment of
In the embodiment of
Sheath 12120 of
Sheath 12120 of
In some useful embodiments, lumen width LW of lumen 12122 is equal to or greater than the width of an implant 12126 disposed in lumen 12122. In some of these useful embodiments, aperture width AW is smaller than the width of the implant 12126. When this is the case, frangible connection 12160 can be selectively broken by moving sheath 12120 in a proximal direction relative to the implant 12126.
Ocular implant 12326 of
A distal portion of body 12328 defines a longitudinal channel 12338 including a channel opening 12339. Channel opening 12339 is disposed diametrically opposite a central portion 12335 of concave surface 12336. In the embodiment of
Accordingly, the terms top view, side view, and bottom view should not be interpreted to limit the scope of the invention recited in the attached claims.
Ocular implant 12526 of
A distal portion of body 12528 defines a longitudinal channel 12538 including a channel opening 12539. Channel opening 12539 is disposed diametrically opposite a central portion 12535 of concave surface 12536. In the embodiment of
In the embodiment of
In some useful embodiments, sheath 12420 comprises a coating disposed on an outer surface thereof. The properties of the coating may be selected to further reduce the trauma inflicted on cells 1290 by the procedure. The coating may comprise, for example, a hydrophilic material. The coating may also comprise, for example, a lubricious polymer. Examples of hydrophilic materials that may be suitable in some applications include: polyalkylene glycols, alkoxy polyalkylene glycols, copolymers of methylvinyl ether and maleic acid poly(vinylpyrrolidone), poly(N-alkylacrylamide), poly(acrylic acid), poly(vinyl alcohol), poly(ethyleneimine), methyl cellulose, carboxymethyl cellulose, polyvinyl sulfonic acid, heparin, dextran, modified dextran and chondroitin sulphate.
In
In the embodiment of
In the embodiment of
In the embodiment of
In the embodiment of
In
Various fabrication techniques may be used to fabricate the ocular implant. For example, the ocular implant can be fabricated by providing a generally flat sheet of material, cutting the sheet of material, and forming the material into a desired shape. By way of a second example, the ocular implant may be fabricated by providing a tube and laser cutting openings in the tube to form the ocular implant.
The ocular implant of this invention can be fabricated from various biocompatible materials possessing the necessary structural and mechanical attributes. Both metallic and non-metallic materials may be suitable. Examples of metallic materials include stainless steel, tantalum, gold, titanium, and nickel-titanium alloys known in the art as Nitinol. Nitinol is commercially available from Memry Technologies (Brookfield, Conn.), TiNi Alloy Company (San Leandro, Calif.), and Shape Memory Applications (Sunnyvale, Calif.).
The ocular implant may include one or more therapeutic agents. One or more therapeutic agents may, for example, be incorporated into a polymeric coating that is deposited onto the outer surfaces of the struts and spines of the ocular implant. The therapeutic agent may comprise, for example, an anti-glaucoma drug. Examples of anti-glaucoma drugs include prostaglandin analogs. Examples of prostaglandin analogs include latanprost.
The implants of the present disclosure provide a treatment for glaucoma by combining the mechanism of trabecular meshwork (TM) bypass and Schlemm's canal (SC) dilation. The trabecular meshwork bypass is achieved through the openings, the longitudinal channel, and channel opening of the implants above, and Schlemm's canal dilation is achieved by supporting Schlemm's canal with the body of the implant itself.
A comprehensive mathematical model was developed in this disclosure to evaluate changes in fluid dynamics of aqueous humor outflow induced by combinations of trabecular mesh bypass and/or Schlemm's canal dilation, and to predict how the changes would affect outflow facility. First, a control eye was modeled after an ex vivo human anterior segment perfusion model using typical dimensions for the eye and Schlemm's canal. This was done in order to validate the model parameters with experimental data. Next, two combinations of bypass and dilation were modeled using the dimensional parameters of implants with 8 mm and 16 mm lengths. The mathematical model was used to predict outflow facilities in control and experimental simulations.
The mathematical model was developed to numerically simulate aqueous humor outflow based on the assumptions and physical principles that govern fluid flow. Schlemm's canal is modeled as a rectangular channel with width (w) and height (h), where h varies with the location (x) along the canal due to trabecular mesh deformation. The trabecular mesh is treated as an elastic membrane in the model. The ostia of collector channels (CC) are distributed uniformly along the outer wall of Schlemm's canal with the first collector channel located at x=0.6 mm or 0=6°. Collector channels are treated as individual sinks with flow rate, JCC (see the governing equation below). Schlemm's canal in the experimental simulations is modeled after either an 8 mm implant or 16 mm implant. The region of Schlemm's canal with an implant is also modeled as a rectangular channel but with width (wd) and height (hd) corresponding to the implant cross-sectional area.
The height of Schlemm's canal (h) is intra-ocular pressure (IOP) dependent. The dependence is assumed to be linear:
h=h0*(1−IOP−PSCE) (1)
Across the trabecular meshwork, the aqueous humor flux (JTM) is dependent on the trabecular mesh resistance (RTM) and is governed by:
In these equations, Psc is the fluid pressure in the Schlemm's canal, E is the Young's modulus of the trabecular meshwork, h0 is the value of h when intra-ocular pressure=Psc, RTM is the trabecular meshwork's resistance to fluid flow, Q is the flow rate along the SC, μ is the viscosity of aqueous humor, xcc indicates locations of collector channel ostia in the Schlemm's canal, JCC is the flow rate in the collector channels, Pepi is the pressure in the episcleral veins, and RCC is the flow resistance of collector channels that may depend on xcc. Since Schlemm's canal is a ring-like channel, the boundary conditions at x=0 for Psc and Q are the same as those at x=L, where L is the circumferential length of Schlemm's canal.
In simulations with an implant such as those described herein, a portion of Schlemm's canal is stretched open. The implant inlet is assumed to be a uni-directional fluid source with zero flow resistance Psc=IOP. The implant is modeled as a channel with three side walls, leaving the side facing the outer wall of Schlemm's canal open. For example,
Two scaffold designs are investigated in this disclosure. One has a total length of 8 mm with 3 windows and 3 spines (shown in
The baseline values of the constants are given in Table 1.
Dimensions of the implants shown in Table 2A-2B are estimated based on the actual sizes except width.
For simplicity, the width of all implants are assumed to be the same as that of the intact Schlemm's canal; and the height of each implant is calculated from the cross-sectional areas estimated for that device divided by wd. In Table 1, the viscosity of aqueous humor (μ) at 37° C. is assumed to be the same as that measured at 34° C., because μ is close to the viscosity of water which changes only slightly (˜6%) when the temperature is increased from 34° C. to 37° C. The pressure in the episcleral vein (Pepi) is close to zero in experiments involving ex vivo perfusion of whole eye or anterior segment, but approximately equal to 8 mmHg in live eyes. In order to apply conclusions obtained from this mathematical model to both types of studies, ΔP was varied between 5 and 30 mmHg, where ΔP=IOP−Pepi, instead of changing the absolute value of IOP. Implantation of a bypass causes a significant increase in the pressure in this region of Schlemm's canal and can lead to an increase in the diameter of collector channel ostia in the region. To account for diameter increase-induced decrease in outflow resistance in collector channels, a parameter, β, can be defined as the ratio of RCC with ostia in control Schlemm's canal versus that in dilated Schlemm's canal. The value of β, which is >1, depends on how the three-dimensional shape of the collector channel is changed due to Schlemm's canal dilation and pressure increase, which is unknown at present. If the collector channel is considered as a circular channel, and its diameter is uniformly increased by a factor of two, then β equals 16 for Newtonian fluid. However, it is likely that only the portion of the collector channel near its ostium is be dilated after device implantation. Thus, a baseline value of β is assumed to be three.
In control simulations, with the frequent and uniform distribution of collector channel ostia in Schlemm's canal, the pressure difference between Schlemm's canal and episcleral venous pressure (Psc−Pepi) showed negligible variation. This resulted in negligible circumferential flow along Schlemm's canal. When the pressure drop between the anterior chamber and episcleral veins (ΔP) was fixed at different pressures, ranging from 5 to 30 mmHg, the shapes of these profiles varied only slightly although their magnitudes were increased significantly. Therefore, only the profiles at 10 mmHg are shown in this disclosure. The total sum of the flow rates through the collector channels per unit ΔP is defined as the outflow facility (C). The average C of the control eye was 0.198 μl/min/mmHg (Table 3). When ΔP is increased from 5 to 30 mmHg, C decreased slightly in the control simulation with TM intact, which falls within the range of experimental data of human eyes reported in the literature.
Consequently, the outflow rate through the collector channels (Jcc) was highest in the implant regions due to the high Psc and Schlemm's canal dilation-induced reduction in outflow resistance in these collector channels. Outside this region, the profile of Jcc matched the Psc profile and was similar for both implants. The collector channels in the scaffold regions contributed to a majority of the overall difference in flow rate through collector channels when compared to controls. The average C value for the 8 mm implant was 121% greater than controls with a C value of 0.438 μl/min/mmHg and the 16 mm implant was 46% greater than the 8 mm implant (222% greater than controls) with a C value of 0.638 μl/min/mmHg (Table 3 above). However, the 16 mm implant reached twice as many collector channels as the 8 mm implant but only gained 46% greater outflow despite the addition of 6 collector channels. This indicates that as the distance from the collector channels to the inlet increases, the benefit to outflow facility diminishes.
Significant circumferential flow was observed adjacent to the trabecular meshwork bypass not seen in control simulations. The peak circumferential flow rate was 3.2 μl/min with the 8 mm implant and 5.7 μl/min with the 16 mm implant. The magnitude of the circumferential flow indicates a significant portion of the total outflow passed through the trabecular mesh bypass inlet. The circumferential flow rate peaked at the position of the bypass and decreased with a linear step pattern in the implant region. At the distal end of the scaffold, the circumferential flow rate decreased exponentially until it reached zero, as shown in
Calculations of the percentage of total aqueous humor outflow through collector channels within an implant region indicate that the longer the implanted region the greater the percentage of total outflow (Table 4).
The 8 mm implant occupied three clock-hours of Schlemm's canal (20% of Schlemm's canal length), however the collector channels in that region accounted for 54.5% of the total outflow in the eye. The 16 mm implant occupied five clock-hours of Schlemm's canal (42% of Schlemm's canal length) which accounted for 74.6% of the total outflow. These results indicate that a significant portion of total outflow is diverted into the implant area and drains out collector channels adjacent to the implant. The more collector channels adjacent to the implant the larger a percentage of total outflow. Likewise, a segmental variation of the collector channel patency would make the outflow facility results dependent on implant location.
Theoretical in vivo glaucoma scenarios were designed to simulate how different ocular implants could improve outflow in eyes with increased trabecular meshwork resistance (RTM) and reduced collector channel outflow capacity in the hemisphere of the implant. Three scenarios were simulated in Table 5, with fixed conventional outflow rate of 1.5 μL/min 27, 28 and Pepi of 10 mmHg.
The first scenario was a normal eye, which assumed RTM to be 2.12 mmHg/4/min and no blocked collector channels. The second scenario assumed RTM to be 6.34 mmHg/4/min and 50% of the collector channels in the implanted hemisphere to be uniformly blocked including the collector channels at the trabecular mesh bypass. The third scenario assumed RTM to be 8.78 mmHg/4/min and 75% of the collector channels in the implanted hemisphere to be uniformly blocked including the collector channel at the trabecular meshwork bypass. Simulation results showed that in the control eye without implant, the intra-ocular pressures under these scenarios were 17, 25 and 30 mmHg, respectively, and based on the Goldmann equation, the corresponding outflow facilities were 0.214, 0.100 and 0.075 μL/min/mmHg, respectively. Implantation of the 8 mm implant would improve the simulated outflow facility to 0.450, 0.240 and 0.171 μL/min/mmHg, or reduce IOPs to 13.3, 16.3 and 18.8 mmHg, respectively. When compared to the control simulations, the 8 mm implant resulted in IOP reductions of 22%, 35% and 37%, respectively.
The model shows the effects of trabecular meshwork bypass and Schlemm's canal dilation on outflow facility and subsequent IOP reduction. In analysis of the dilation length, increasing the dilated portion of Schlemm's canal from the bypass improved outflow facility. But, at a certain distance from the bypass there was diminished improvement. This indicates that dilation near the bypass creates circumferential flow from the bypass which allows more collector channels to be utilized.
Fluid dynamic mathematical modeling of scaffolding ocular implants as described herein shows that bypassing the trabecular meshwork increases the pressure within Schlemm's canal, and increases circumferential flow rate, and the flow rate into collector channels adjacent to the trabecular meshwork bypass. The larger bypass size creates a larger increase in the circumferential flow when compared with controls. Dilation of Schlemm's canal adjacent to the trabecular meshwork bypass increases the pressure in Schlemm's canal in the area of dilation which further increases the circumferential flow. Increasing the length of dilation increases the number of collector channels accessed by the implant, however, there was diminishing improvement in circumferential flow and flow rate into collector channels over a distance of approximately one quadrant in the eye beyond the region with the implant. When trabecular meshwork resistance was increased and collector channels were closed segmentally to simulate glaucoma, the dependence on the location of trabecular meshwork bypass to collector channels and the dilation length of Schlemm's canal was more pronounced.
While exemplary embodiments of the present invention have been shown and described, modifications may be made, and it is therefore intended in the appended claims to cover all such changes and modifications which fall within the true spirit and scope of the invention.
Claims
1. An ocular implant comprising:
- a longitudinally extending body having an inlet portion and a Schlemm's canal portion distal to the inlet portion, the inlet portion being configured to extend into and be in fluid communication with an anterior chamber of a human eye and the Schlemm's canal portion being configured to be inserted into Schlemm's canal adjacent to collector channels of the eye;
- a plurality of alternating spines and frames positioned longitudinally along at least a portion of the Schlemm's canal portion wherein the plurality of alternating spines and frames define a central channel extending therethrough, with the central channel being in fluid communication with the inlet portion;
- each of the spines having edges partially defining an opening across from the central channel and in fluid communication with the central channel; and
- each of the frames including first and second struts, the first and second struts each having an edge contiguous with an edge of an adjacent spine, the edges defining the opening in fluid communication with the central channel;
- wherein the ocular implant is configured to provide at least a 121% increase in average outflow facility of aqueous humor from the anterior chamber through the collector channels of the eye.
2. The ocular implant of claim 1, wherein the implant comprises at least three openings across from the central channel.
3. The ocular implant of claim 2, wherein the average outflow facility comprises 0.438 μl/min/mmHg.
4. The ocular implant of claim 2, wherein a peak circumferential flow rate through the ocular implant comprises 3.2 μl/min.
5. The ocular implant of claim 1, wherein the implant comprises at least six openings across from the central channel.
6. The ocular implant of claim 5, wherein the average outflow facility comprises 0.638 μl/min/mmHg.
7. The ocular implant of claim 5, wherein a peak circumferential flow rate through the ocular implant comprises 5.7 μl/min.
8. The ocular implant of claim 1, wherein the average outflow facility of the eye prior to implantation of the ocular implant comprises 0.138 μl/min/mmHg.
9. An ocular implant adapted to reside at least partially in a portion of Schlemm's canal of an eye adjacent to collector channels of the eye, the implant comprising:
- a longitudinally extending curved body including a proximal portion and a distal portion;
- the distal portion of the curved body defining a longitudinal channel including a channel opening; and
- the curved body being adapted and configured such that the distal portion of the curved body resides in Schlemm's canal and the proximal portion extends into the anterior space of the eye while the ocular implant assumes an orientation in which the channel opening is adjacent a major side of Schlemm's canal when the ocular implant is implanted;
- wherein the ocular implant is configured to provide a 121%-222% increase in average outflow facility of aqueous humor from the anterior chamber through the collector channels of the eye.
10. The ocular implant of claim 9, wherein the implant comprises at least three openings across from the central channel.
11. The ocular implant of claim 10, wherein the average outflow facility comprises 0.438 μl/min/mmHg.
12. The ocular implant of claim 10, wherein a peak circumferential flow rate through the ocular implant comprises 3.2 μl/min.
13. The ocular implant of claim 9, wherein the implant comprises at least six openings across from the central channel.
14. The ocular implant of claim 13, wherein the average outflow facility comprises 0.638 μl/min/mmHg.
15. The ocular implant of claim 13, wherein a peak circumferential flow rate through the ocular implant comprises 5.70 min.
16. The ocular implant of claim 9, wherein the average outflow facility of the eye prior to implantation of the ocular implant comprises 0.138 μl/min/mmHg.
17. The ocular implant of claim 10, wherein the distal portion of the curved body occupies up to 20% of Schlemm's canal but accounts for up to 54.5% of total outflow in the eye.
18. The ocular implant of claim 13, wherein the distal portion of the curved body occupies up to 40% of Schlemm's canal but accounts for up to 74.6% of total outflow in the eye.
19. An ocular implant comprising an inlet portion and a Schlemm's canal portion distal to the inlet portion, the inlet portion being disposed at a proximal end of the implant and sized and configured to be placed within an anterior chamber of a human eye, the inlet portion having an inlet adapted to be in fluid communication with the anterior chamber, the Schlemm's canal portion comprising:
- a central channel in fluid communication with the inlet, the central channel extending longitudinally in the Schlemm's canal portion;
- a first element disposed along the central channel;
- a second element disposed along the central channel distal to the first element;
- a third element disposed along the central channel distal to the first element and proximal to the second;
- a fourth element disposed along the central channel distal to the second element;
- the first, second, third and fourth elements each comprising two edges partially defining an elongate opening in fluid communication with the central channel, each of the first, second, third and fourth elements having circumferential extents less than 360 degrees so that the elongate opening extends continuously along the first, second, third and fourth elements, the circumferential extents of the first and second elements being less than the circumferential extents of the third and fourth elements;
- the Schlemm's canal portion being arranged and configured to be disposed within Schlemm's canal of the eye when the inlet portion is disposed in the anterior chamber, wherein the ocular implant is configured to provide a 121%-222% increase in average outflow facility of aqueous humor from the anterior chamber through the collector channels of the eye.
20. The ocular implant of claim 19, wherein the implant comprises at least three openings across from the central channel.
21. The ocular implant of claim 20, wherein the average outflow facility comprises 0.438 μl/min/mmHg.
22. The ocular implant of claim 20, wherein a peak circumferential flow rate through the ocular implant comprises 3.2 μl/min.
23. The ocular implant of claim 19, wherein the implant comprises at least six openings across from the central channel.
24. The ocular implant of claim 23, wherein the average outflow facility comprises 0.638 μl/min/mmHg.
25. The ocular implant of claim 23, wherein a peak circumferential flow rate through the ocular implant comprises 5.7 μl/min.
26. The ocular implant of claim 19, wherein the average outflow facility of the eye prior to implantation of the ocular implant comprises 0.138 μl/min/mmHg.
27. The ocular implant of claim 20, wherein the Schlemm's canal portion occupies up to 20% of Schlemm's canal but accounts for up to 54.5% of total outflow in the eye.
28. The ocular implant of claim 23, wherein the Schlemm's canal portion occupies up to 40% of Schlemm's canal but accounts for up to 74.6% of total outflow in the eye.
29. A method of treating glaucoma comprising:
- supporting tissue forming Schlemm's canal in an eye with an implant extending at least partially in the canal along an axial length within the canal;
- contacting with the implant less than 50% of the tissue forming the canal along the axial length
- disposing an inlet portion of the implant in an anterior chamber of the eye; and
- providing fluid communication between the anterior chamber and the canal axially through the inlet into a channel of the implant such that an average outflow facility between the anterior chamber and the canal is increased by 121%-222%; and
- wherein the implant comprises open areas separated by spine areas along a first longitudinal section, the spine areas partially defining the channel, the supporting step comprising orienting the first longitudinal section openings towards a trabecular mesh portion of the canal.
30. An ocular implant adapted to reside at least partially in a portion of Schlemm's canal of a human eye, the implant comprising:
- a body configured to extend within Schlemm's canal in a curved volume having a large radius side and a short radius side, the body having a circumferential extent within the curved volume that varies along the length of the body between sections having a lesser circumferential extent and sections having a greater circumferential extent, wherein the body defines a channel extending longitudinally through the body, the channel having a substantially open side disposed on the large radius side at one of the sections of lesser circumferential extent and an adjacent section of greater circumferential extent and a plurality of openings along the length of the body on the short radius side, the openings being in fluid communication with the channel; and,
- an inlet portion configured to be disposed in an anterior chamber of the eye when the body is in Schlemm's canal, the inlet portion disposed on a proximal end of the body in fluid communication with the channel, the inlet portion defining one or more openings in fluid communication with the anterior chamber of the eye;
- wherein the ocular implant is configured to provide a 121%-222% increase in average outflow facility of aqueous humor from the anterior chamber through the collector channels of the eye.
31. An ocular implant adapted to reside at least partially in a portion of Schlemm's canal of an eye, the eye having an iris defining a pupil, the implant comprising:
- a longitudinally extending curved body including a proximal portion and a distal portion, the distal portion of the curved body having a central longitudinal axis defined by a radius of curvature and a lateral cross section having a first lateral extent and a second lateral extent, an aspect ratio of the first lateral extent to the second lateral extent being greater than or equal to about two;
- the distal portion of the curved body defining a longitudinal channel including a channel opening, the channel opening included in defining the first lateral extent;
- the curved body being adapted and configured such that the distal portion of the curved body resides in Schlemm's canal and the proximal portion extends into the anterior space of the eye while the ocular implant assumes an orientation in which the channel opening is adjacent a major side of Schlemm's canal when the ocular implant is implanted; and
- wherein the ocular implant is configured to provide a 121%-222% increase in average outflow facility of aqueous humor from the anterior chamber through the collector channels of the eye.
Type: Application
Filed: Feb 1, 2016
Publication Date: Aug 4, 2016
Inventors: Andrew T. SCHIEBER (Irvine, CA), Charles L. EUTENEUER (St. Michael, MN)
Application Number: 15/012,544
