U.S. patent application number 11/836109 was filed with the patent office on 2007-12-06 for glaucoma implant with anchor.
This patent application is currently assigned to GLAUKOS CORPORATION. Invention is credited to Olav B. Bergheim, Morteza Gharib, Hosheng Tu.
Application Number | 20070282244 11/836109 |
Document ID | / |
Family ID | 24192643 |
Filed Date | 2007-12-06 |
United States Patent
Application |
20070282244 |
Kind Code |
A1 |
Tu; Hosheng ; et
al. |
December 6, 2007 |
GLAUCOMA IMPLANT WITH ANCHOR
Abstract
A glaucoma treatment device for directing the flow of aqueous
humor and bypassing trabecular meshwork is shown. The device
includes an inlet section, an outlet section, a middle section, and
at least one lumen for transmitting aqueous humor within the
glaucoma device. The lumen extends through at least one of the
sections, and the outlet section is substantially perpendicular to
the middle section and fits within a conduit of aqueous humor
outflow in the eye.
Inventors: |
Tu; Hosheng; (Newport Coast,
CA) ; Bergheim; Olav B.; (Laguna Hills, CA) ;
Gharib; Morteza; (San Marino, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Assignee: |
GLAUKOS CORPORATION
26051 Merit Circle, Suite 103
Laguna Hills
CA
92653
|
Family ID: |
24192643 |
Appl. No.: |
11/836109 |
Filed: |
August 8, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
10824052 |
Apr 14, 2004 |
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|
11836109 |
Aug 8, 2007 |
|
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09704276 |
Nov 1, 2000 |
6736791 |
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10824052 |
Apr 14, 2004 |
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09549350 |
Apr 14, 2000 |
6638239 |
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09704276 |
Nov 1, 2000 |
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Current U.S.
Class: |
604/8 |
Current CPC
Class: |
A61F 2009/00891
20130101; A61F 2250/0067 20130101; A61K 9/0051 20130101; A61M
27/002 20130101; A61F 9/00781 20130101; A61F 9/007 20130101; A61F
9/0017 20130101; Y10S 623/905 20130101; A61P 27/06 20180101; A61M
2210/0612 20130101 |
Class at
Publication: |
604/008 |
International
Class: |
A61M 27/00 20060101
A61M027/00 |
Claims
1. A method of reducing intraocular pressure, comprising: providing
an implant having a proximal portion and a distal portion, at least
one fluid pathway extending between the proximal and distal
portions, a first anchor disposed at the proximal portion and a
second anchor disposed at the distal portion; and implanting the
implant in eye tissue such that the fluid pathway drains aqueous
humor from an anterior chamber of an eye to a physiologic outflow
pathway of the eye and that eye tissue resides between the first
and second anchors with the first anchor being disposed in the
anterior chamber.
2. The method of claim 1 additionally comprising forming a corneal
incision, introducing the implant into the anterior chamber through
said corneal incision, and advancing the implant through the
anterior chamber to an insertion site in said eye tissue.
3. The method of claim 2, wherein the corneal incision is formed on
a side of the eye that is generally opposite of the eye tissue in
which the implant is to be implanted, and the implant is advanced
across the anterior chamber from the corneal incision to the
insertion site.
4. The method of claim 1, wherein implanting involves inserting the
implant through a trabecular meshwork of the eye and positioning
the distal portion within Schlemm's canal of the eye.
5. The method of claim 4, wherein implanting involves positioning
the first anchor within the anterior chamber of the eye and the
second anchor within the physiologic outflow pathway.
6. The method of claim 5, wherein the second anchor is positioned
within Schlemm's canal.
7. A method of reducing intraocular pressure, comprising:
implanting an implant in eye tissue such that a fluid pathway
through the implant drains aqueous humor from an anterior chamber
of an eye to a physiologic outflow pathway within the eye;
positioning a first anchor in the anterior chamber to inhibit
migration of the implant toward the physiologic outflow pathway;
and positioning a second anchor in the physiologic outflow pathway
to inhibit migration of the implant toward the anterior
chamber.
8. The method of claim 7 additionally comprising the step of
providing an implant with the first and second anchors affixed
thereon.
9. The method of claim 7 additionally comprising the step of
providing an implant having the first and second anchors spaced
apart by a distance that substantially corresponds to a distance
between the anterior chamber and the physiologic outflow
pathway.
10. The method of claim 7, wherein positioning the second anchor
involves inserting the second anchor through a trabecular meshwork
of the eye and into Schlemm's canal of the eye.
11. The method of claim 7 additionally comprising forming a corneal
incision, introducing the implant into the anterior chamber through
said corneal incision, and advancing the implant through the
anterior chamber to an insertion site.
12. The method of claim 11, wherein the corneal incision is formed
on a side of the eye that is generally opposite of the eye tissue
in which the implant is to be implanted, and the implant is
advanced across the anterior chamber from the corneal incision to
the insertion site.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
patent application Ser. No. 10/824,052, filed Apr. 14, 2004, which
is a continuation application of U.S. patent application Ser. No.
09/704,276, filed Nov. 1, 2000, now U.S. Pat. No. 6,736,791 B1,
issued May 18, 2004, which is a continuation-in-part (CIP)
application of U.S. patent application Ser. No. 09/549,350, filed
Apr. 14, 2000, now U.S. Pat. No. 6,638,239 B1, issued Oct. 28,
2003, the entire contents of each of which are herein incorporated
by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention generally relates to medical devices
and methods for reducing intraocular pressure in the animal eye.
More particularly, the present invention relates to the treatment
of glaucoma by permitting aqueous humor to flow out of the anterior
chamber through a surgically implanted pathway.
[0003] The human eye is a specialized sensory organ capable of
light reception and able to receive visual images. The trabecular
meshwork serves as a drainage channel and is located in anterior
chamber angle formed between the iris and the cornea. The
trabecular meshwork maintains a balanced pressure in the anterior
chamber of the eye by draining aqueous humor from the anterior
chamber.
[0004] About two percent of people in the United States have
glaucoma. Glaucoma is a group of eye diseases encompassing a broad
spectrum of clinical presentations, etiologies, and treatment
modalities. Glaucoma causes pathological changes in the optic
nerve, visible on the optic disk, and it causes corresponding
visual field loss, resulting in blindness if untreated. Lowering
intraocular pressure is the major treatment goal in all
glaucomas.
[0005] In glaucomas associated with an elevation in eye pressure
(intraocular hypertension), the source of resistance to outflow is
mainly in the trabecular meshwork. The tissue of the trabecular
meshwork allows the aqueous humor ("aqueous") to enter Schlemm's
canal, which then empties into aqueous collector channels in the
posterior wall of Schlemm's canal and then into aqueous veins,
which form the episcleral venous system. Aqueous humor is a
transparent liquid that fills the region between the cornea, at the
front of the eye, and the lens. The aqueous humor is continuously
secreted by the ciliary body around the lens, so there is a
constant flow of aqueous humor from the ciliary body to the eye's
front chamber. The eye's pressure is determined by a balance
between the production of aqueous and its exit through the
trabecular meshwork (major route) or uveal scleral outflow (minor
route). The trabecular meshwork is located between the outer rim of
the iris and the back of the cornea, in the anterior chamber angle.
The portion of the trabecular meshwork adjacent to Schlemm's canal
(the juxtacanilicular meshwork) causes most of the resistance to
aqueous outflow.
[0006] Glaucoma is grossly classified into two categories:
closed-angle glaucoma, also known as angle closure glaucoma, and
open-angle glaucoma. Closed-angle glaucoma is caused by closure of
the anterior chamber angle by contact between the iris and the
inner surface of the trabecular meshwork. Closure of this
anatomical angle prevents normal drainage of aqueous humor from the
anterior chamber of the eye. Open-angle glaucoma is any glaucoma in
which the angle of the anterior chamber remains open, but the exit
of aqueous through the trabecular meshwork is diminished. The exact
cause for diminished filtration is unknown for most cases of
open-angle glaucoma. Primary open-angle glaucoma is the most common
of the glaucomas, and it is often asymptomatic in the early to
moderately advanced stage. Patients may suffer substantial,
irreversible vision loss prior to diagnosis and treatment. However,
there are secondary open-angle glaucomas which may include edema or
swelling of the trabecular spaces (e.g., from corticosteroid use),
abnormal pigment dispersion, or diseases such as hyperthyroidism
that produce vascular congestion.
[0007] All current therapies for glaucoma are directed at
decreasing intraocular pressure. Medical therapy includes topical
ophthalmic drops or oral medications that reduce the production or
increase the outflow of aqueous. However, these drug therapies for
glaucoma are sometimes associated with significant side effects,
such as headache, blurred vision, allergic reactions, death from
cardiopulmonary complications, and potential interactions with
other drugs. When drug therapy fails, surgical therapy is used.
Surgical therapy for open-angle glaucoma consists of laser
trabeculoplasty, trabeculectomy, and implantation of aqueous shunts
after failure of trabeculectomy or if trabeculectomy is unlikely to
succeed. Trabeculectomy is a major surgery that is widely used and
is augmented with topically applied anticancer drugs, such as
5-flurouracil or mitomycin-C to decrease scarring and increase the
likelihood of surgical success.
[0008] Approximately 100,000 trabeculectomies are performed on
Medicare-age patients per year in the United States. This number
would likely increase if the morbidity associated with
trabeculectomy could be decreased. The current morbidity associated
with trabeculectomy consists of failure (10-15%); infection (a life
long risk of 2-5%); choroidal hemorrhage, a severe internal
hemorrhage from low intraocular pressure, resulting in visual loss
(1%); cataract formation; and hypotony maculopathy (potentially
reversible visual loss from low intraocular pressure).
[0009] For these reasons, surgeons have tried for decades to
develop a workable surgery for the trabecular meshwork.
[0010] The surgical techniques that have been tried and practiced
are goniotomy/trabeculotomy and other mechanical disruptions of the
trabecular meshwork, such as trabeculopuncture, goniophotoablation,
laser trabecular ablation, and goniocurretage. These are all major
operations and are briefly described below.
[0011] Goniotomy/Trabeculotomy: Goniotomy and trabeculotomy are
simple and directed techniques of microsurgical dissection with
mechanical disruption of the trabecular meshwork. These initially
had early favorable responses in the treatment of open-angle
glaucoma. However, long-term review of surgical results showed only
limited success in adults. In retrospect, these procedures probably
failed due to cellular repair and fibrosis mechanisms and a process
of "filling in." Filling in is a detrimental effect of collapsing
and closing in of the created opening in the trabecular meshwork.
Once the created openings close, the pressure builds back up and
the surgery fails.
[0012] Trabeculopuncture: Q-switched Neodymiun (Nd) YAG lasers also
have been investigated as an optically invasive technique for
creating full-thickness holes in trabecular meshwork. However, the
relatively small hole created by this trabeculopuncture technique
exhibits a filling-in effect and fails.
[0013] Goniophotoablation/Laser Trabecular Ablation:
Goniophotoablation is disclosed by Berlin in U.S. Pat. No.
4,846,172 and involves the use of an excimer laser to treat
glaucoma by ablating the trabecular meshwork. This was demonstrated
not to succeed by clinical trial. Hill et al. used an Erbium:YAG
laser to create full-thickness holes through trabecular meshwork
(Hill et al., Lasers in Surgery and Medicine 11:341-346, 1991).
This technique was investigated in a primate model and a limited
human clinical trial at the University of California, Irvine.
Although morbidity was zero in both trials, success rates did not
warrant further human trials. Failure was again from filling in of
surgically created defects in the trabecular meshwork by repair
mechanisms. Neither of these is a viable surgical technique for the
treatment of glaucoma.
[0014] Goniocurretage: This is an ab interno (from the inside),
mechanically disruptive technique that uses an instrument similar
to a cyclodialysis spatula with a microcurrette at the tip. Initial
results were similar to trabeculotomy: it failed due to repair
mechanisms and a process of filling in.
[0015] Although trabeculectomy is the most commonly performed
filtering surgery, viscocanulostomy (VC) and non-penetrating
trabeculectomy (NPT) are two new variations of filtering surgery.
These are ab externo (from the outside), major ocular procedures in
which Schlemm's canal is surgically exposed by making a large and
very deep scleral flap. In the VC procedure, Schlemm's canal is
cannulated and viscoelastic substance injected (which dilates
Schlemm's canal and the aqueous collector channels). In the NPT
procedure, the inner wall of Schlemm's canal is stripped off after
surgically exposing the canal.
[0016] Trabeculectomy, VC, and NPT involve the formation of an
opening or hole under the conjunctiva and scleral flap into the
anterior chamber, such that aqueous humor is drained onto the
surface of the eye or into the tissues located within the lateral
wall of the eye. These surgical operations are major procedures
with significant ocular morbidity. When trabeculectomy, VC, and NPT
are thought to have a low chance for success, a number of
implantable drainage devices have been used to ensure that the
desired filtration and outflow of aqueous humor through the
surgical opening will continue. The risk of placing a glaucoma
drainage device also includes hemorrhage, infection, and diplopia
(double vision).
[0017] Examples of implantable shunts and surgical methods for
maintaining an opening for the release of aqueous humor from the
anterior chamber of the eye to the sclera or space beneath the
conjunctiva have been disclosed in, for example, U.S. Pat. No.
6,059,772 to Hsia et al., and U.S. Pat. No. 6,050,970 to
Baerveldt.
[0018] All of the above embodiments and variations thereof have
numerous disadvantages and moderate success rates. They involve
substantial trauma to the eye and require great surgical skill in
creating a hole through the full thickness of the sclera into the
subconjunctival space. The procedures are generally performed in an
operating room and have a prolonged recovery time for vision.
[0019] The complications of existing filtration surgery have
inspired ophthalmic surgeons to find other approaches to lowering
intraocular pressure.
[0020] The trabecular meshwork and juxtacanilicular tissue together
provide the majority of resistance to the outflow of aqueous and,
as such, are logical targets for surgical removal in the treatment
of open-angle glaucoma. In addition, minimal amounts of tissue are
altered and existing physiologic outflow pathways are utilized.
[0021] As reported in Arch. Ophthalm. (2000) 118:412, glaucoma
remains a leading cause of blindness, and filtration surgery
remains an effective, important option in controlling the disease.
However, modifying existing filtering surgery techniques in any
profound way to increase their effectiveness appears to have
reached a dead end. The article further states that the time has
come to boldly examine new surgical approaches that may provide
better and safer care for patients with glaucoma.
[0022] Therefore, there is a great clinical need for the treatment
of glaucoma by a method that is faster, safer, and less expensive
than currently available modalities.
SUMMARY OF THE INVENTION
[0023] Glaucoma surgical morbidity would greatly decrease if one
were to bypass the focal resistance to outflow of aqueous only at
the point of resistance, and to utilize remaining, healthy aqueous
outflow mechanisms. This is in part because episcleral aqueous
humor exerts a backpressure that prevents intraocular pressure from
going too low, and one could thereby avoid hypotony. Thus, such a
surgery would virtually eliminate the risk of hypotony-related
maculopathy and choroidal hemorrhage. Furthermore, visual recovery
would be very rapid, and the risk of infection would be very small
(a reduction from 2-5% to about 0.05%).
[0024] Techniques performed in accordance with the present
invention may be referred to generally as "trabecular bypass
surgery." Advantages of the present invention include lowering
intraocular pressure in a manner which is simple, effective,
disease site-specific, and can potentially be performed on an
outpatient basis.
[0025] In accordance with one aspect of the invention, trabecular
bypass surgery (TBS) creates an opening, a slit, or a hole through
trabecular meshwork with minor microsurgery. TBS has the advantage
of a much lower risk of choroidal hemorrhage and infection than
prior techniques, and it uses existing physiologic outflow
mechanisms. In some aspects, this surgery can potentially be
performed under topical or local anesthesia on an outpatient basis
with rapid visual recovery. To prevent "filling in" of the hole, a
biocompatible elongated device is placed within the hole, serving
as a stent.
[0026] In some embodiments, the device may be positioned across
trabecular meshwork alone, without extending into the eye wall or
sclera. The inlet end of the device is exposed to the anterior
chamber of the eye while the outlet end is positioned at the
exterior surface of the trabecular meshwork. In another embodiment,
the outlet end is positioned at the exterior surface of the
trabecular meshwork and into the fluid collection channels of the
existing outflow pathways. In still another embodiment, the outlet
end is positioned in Schlemm's canal. In an alternative embodiment,
the outlet end enters into fluid collection channels (e.g., aqueous
collector channels) up to the level of the aqueous veins, with the
device inserted in a retrograde or antegrade fashion.
[0027] In some embodiments, the device is made of biocompatible
material, which is either hollow, to allow the flow of aqueous
humor, or solid, porous material that imbibes aqueous humor. One or
more materials for the device may be selected from the following
material types: porous material, semi-rigid material, soft
material, hydrophilic material, hydrophobic material, hydrogel,
elastic material, biodegradable material, and the like.
[0028] One or more materials for the glaucoma device may be
selected from the following: polyvinyl alcohol, polyvinyl
pyrolidone, collagen, heparinized collagen,
polytetrafluoroethylene, expanded polytetrafluoroethylene,
fluorinated polymer, fluorinated elastomer, flexible fused silica,
polyolefin, polyester, polyimide, polysilison, silicone,
polyurethane, Nylon, polypropylene, hydroxyapetite, titanium, and
precious metal (e.g., gold, silver, or platinum). Other suitable
filter types and materials for the device may be used in accordance
with the invention and will be apparent to those of skill in the
art.
[0029] In accordance with a further aspect of the invention, the
device is relatively soft and somewhat curved at its outlet section
to fit into the existing outflow pathways, such as Schlemm's canal.
The outlet section may be curved around a curve center, and the
middle section may extend substantially along a plane that contains
the curve center. All or a portion of the cross section of one or
more lumens may be in an elliptical (e.g., oval) shape.
Furthermore, the outlet section inside the outflow pathway may have
an appropriate shape, e.g., with a protuberance or barb projecting
from it, to stabilize the device in place without undue
suturing.
[0030] One aspect of the invention includes a method of placing a
glaucoma device into an opening through trabecular meshwork and
into an outflow pathway for aqueous humor. This glaucoma device
includes an inlet section, an outlet section, and a middle section
between the inlet section and the outlet section. The glaucoma
device also includes at least one lumen that extends within at
least one of the three sections for transmitting aqueous humor, and
the outlet section is substantially perpendicular to the middle
section. The outlet section includes a first outlet end and a
second outlet end. In this aspect of the invention, the method
includes advancing the first outlet end of the outlet section
through the opening into a first part of the outflow pathway, and
advancing the second outlet end of the outlet section through the
opening into a second part of the outflow pathway.
[0031] The outlet section is, in one embodiment, an elongated
element having a first outlet end and a second outlet end, wherein
the middle section is connected to the outlet section between the
first outlet end and the second outlet end. Stabilization or
retention of the device in the eye may be further strengthened by
inserting the first outlet end into a first side of Schlemm's
canal, then inserting the second outlet end into a second, opposite
side of Schlenun's canal. The angle between the long axis of the
inlet section and the long axis of the middle section is
advantageously between about 20 degrees and about 150 degrees, and
preferably between about 30 degrees and about 60 degrees. This
angle adapts the device for positioning the inlet section inside
the anterior chamber of an eye.
[0032] In one embodiment, the device of the invention may include a
flow-restricting member for restricting at least one component in
fluid. The flow-restricting member may be a filter comprising one
or more filtration materials selected from the following: expanded
polytetrafluoroethylene, cellulose, ceramic, glass, Nylon, plastic,
fluorinated material, or the like. The flow-restricting member may
advantageously be a filter selected from the following group of
filter types: hydrophobic, hydrophilic, membrane, microporous, and
non-woven. The flow-restricting member acts to limit or prevent the
reflux of any undesired component or contaminant of blood, such as
red blood cells or serum protein, from the aqueous veins into the
anterior chamber. It is useful to restrict one or more of the
following component or contaminants: platelets, red blood cells,
white blood cells, viruses, bacteria, antigens, and toxins.
[0033] In an alternate embodiment, the method may further include
inserting a guidewire into the first part of the outflow pathway,
wherein the step of advancing the first outlet end of the outlet
section includes advancing the glaucoma device along the
guidewire.
[0034] Among the advantages of trabecular bypass surgery in
accordance with the invention is its simplicity. The microsurgery
may potentially be performed on an outpatient basis with rapid
visual recovery and greatly decreased morbidity. There is a lower
risk of infection and choroidal hemorrhage, and there is a faster
recovery, than with previous techniques.
[0035] Further features and advantages of the present invention
will become apparent to one of skill in the art in view of the
Detailed Description that follows, when considered together with
the attached drawings and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1 is a sagittal sectional view of an eye.
[0037] FIG. 2 is a cross-sectional view of the anterior chamber of
an eye.
[0038] FIG. 3 is an oblique elevational view of a glaucoma device
according to the present invention.
[0039] FIG. 3A is a schematic view of the glaucoma device having
plural lumens.
[0040] FIG. 4 is an oblique elevational view of the glaucoma
device, featuring an open trough configuration.
[0041] FIG. 5A illustrates placement of one end of the glaucoma
device through trabecular meshwork in accordance with the present
invention.
[0042] FIG. 5B illustrates an alternate method of placement of one
end of the glaucoma device through trabecular meshwork, over a
guidewire.
[0043] FIG. 6 illustrates completed placement of the glaucoma
device through trabecular meshwork.
[0044] FIG. 7 illustrates a method of placement of the glaucoma
device in an eye in accordance with the present invention.
[0045] FIG. 8 is a perspective view of the anterior chamber of an
eye, illustrating the glaucoma device of the present invention
positioned within the trabecular meshwork.
[0046] FIG. 9 is a close-up view of the inlet section of the
glaucoma device in accordance with the present invention,
illustrating a flow-restricting member inside the lumen of the
inlet section.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0047] FIGS. 1 to 9 illustrate an apparatus for the treatment of
glaucoma by trabecular bypass surgery in accordance with the
present invention.
[0048] FIG. 1 is a sagittal sectional view of an eye 10, while FIG.
2 shows a close-up view, showing the relative anatomical locations
of trabecular meshwork 21, the anterior chamber 20, and Schlemm's
canal 22. Thick collagenous tissue known as sclera 11 covers the
entire eye 10 except that portion covered by the cornea 12. The
cornea 12 is a thin transparent tissue that focuses and transmits
light into the eye and through the pupil 14, which is the circular
hole in the center of the iris 13 (colored portion of the eye). The
cornea 12 merges into the sclera 11 at a juncture referred to as
the limbus 15. The ciliary body 16 extends along the interior of
the sclera 11 and is coextensive with the choroid 17. The choroid
17 is a vascular layer of the eye 10, located between the sclera 11
and retina 18. The optic nerve 19 transmits visual information to
the brain and is the anatomic structure that is progressively
destroyed by glaucoma.
[0049] The anterior chamber 20 of the eye 10, which is bound
anteriorly by the cornea 12 and posteriorly by the iris 13 and lens
26, is filled with aqueous humor ("aqueous"). Aqueous is produced
primarily by the ciliary body 16, then moves anteriorly through the
pupil 14 and reaches the anterior chamber angle 25, formed between
the iris 13 and the cornea 12. In a normal eye, the aqueous is
removed from the anterior chamber 20 through the trabecular
meshwork 21. Aqueous passes through trabecular meshwork 21 into
Schlemm's canal 22 and thereafter through the aqueous veins 23,
which merge with blood-carrying veins and into systemic venous
circulation. Intraocular pressure is maintained by the intricate
balance between secretion and outflow of the aqueous in the manner
described above. Glaucoma is, in most cases, characterized by the
excessive buildup of aqueous humor in the anterior chamber 20,
which leads to an increase in intraocular pressure. Fluids are
relatively incompressible, and pressure is directed relatively
equally throughout the eye.
[0050] As shown in FIG. 2, the trabecular meshwork 21 is adjacent a
small portion of the sclera 11. Traditional procedures that create
a hole or opening for implanting a device through the tissues of
the conjunctiva 24 and sclera 11 involve extensive surgery, as
compared to surgery for implanting a device which ultimately
resides entirely within the confines of the sclera 11 and cornea
12, as is performed in accordance with one aspect of the present
invention. A device 31 for establishing an outflow pathway,
positioned through the trabecular meshwork 21, is illustrated in
FIG. 8.
[0051] One aspect of the invention includes a method for increasing
aqueous humor outflow in an eye of a patient, to reduce the
intraocular pressure therein. The method comprises bypassing the
trabecular meshwork 21. The device 31 may be elongate or of other
appropriate shape, size, or configuration, as will be evident to
those of skill in the art. In one embodiment, illustrated in FIG.
3, the device has an inlet section 2 with an inlet opening 3, a
middle section 4, and an outlet section 9. There is also at least
one lumen inside at least one of the sections for transmitting
aqueous humor. The inlet section is typically positioned at an
anterior chamber 20 of the eye and the outlet section 9 is
preferably positioned at about an exterior surface of the
trabecular meshwork 21. The outlet section 9 is, in some
embodiments, substantially perpendicular to the middle section 4.
"Substantially perpendicular," as used herein, is defined as
subtending an angle between the long axes of the sections (e.g.,
the outlet section 9 and middle section 4) of between about 30
degrees and about 150 degrees. An alternate embodiment having
plural lumens, with plural openings 3B, is depicted in FIG. 3A.
[0052] The middle section 4 is advantageously placed across the
trabecular meshwork 21 through a slit or opening. This opening can
be created by laser, a knife, or other surgical cutting instrument.
The opening may advantageously be substantially horizontal, i.e.,
extending longitudinally in the same direction as the circumference
of the limbus 15. Other opening directions may also be used, such
as horizontal or at any angle that is appropriate for inserting the
glaucoma device through the trabecular meshwork 21 and into
Schlemm's canal or another outflow pathway, as will be apparent to
those of skill in the art. The middle section 4 may be
semi-flexible and/or adjustable in position relative to the inlet
section 2 and/or outlet section 9, further adapting the device for
simple and safe glaucoma implantation. Furthermore, the outlet
section 9 may be positioned into fluid collection channels of the
natural outflow pathways. Such natural outflow pathways include
Schlemm's canal 22, aqueous collector channels, aqueous veins, and
episcleral veins. The outlet section 9 may be positioned into fluid
collection channels up to at least the level of the aqueous veins,
with the device inserted in a retrograde or antegrade fashion.
[0053] A further aspect of the invention includes methods for
increasing aqueous humor outflow in an eye of a patient to reduce
an intraocular pressure therein. The method comprises the
following: (a) creating an opening in the trabecular meshwork 21,
wherein the trabecular meshwork 21 includes a deep side and
superficial side; (b) inserting a glaucoma device into the opening;
and (c) transmitting aqueous humor through the device, to bypass
the trabecular meshwork 21, from the deep side to the superficial
side of the trabecular meshwork 21. This "transmitting" of aqueous
humor is, in one aspect of the invention, preferably passive, i.e.,
aqueous humor is allowed to flow out of the anterior chamber due to
the pressure gradient between the anterior chamber and the aqueous
venous system.
[0054] FIG. 3 shows an embodiment of the glaucoma device 31
according to the principles of the invention. The device may
comprise a biocompatible material, such as medical grade silicone,
e.g., SILASTIC.RTM., available from Dow Corning Corporation of
Midland, Mich.; or polyurethane, e.g., PELLETHANE.RTM., also
available from Dow Corning Corporation.
[0055] In an alternate embodiment, other biocompatible material
(biomaterial) may be used, such as polyvinyl alcohol, polyvinyl
pyrolidone, collagen, heparinized collagen,
polytetrafluoroethylene, expanded polytetrafluoroethylene,
fluorinated polymer, fluorinated elastomer, flexible fused silica,
polyolefin, polyester, polysilison, mixture of biocompatible
materials, and the like. In a further embodiment, a composite
biocompatible material may be used, wherein a surface material may
be used in addition to one or more of the aforementioned materials.
Such a surface material may include polytetrafluoroethylene
("PTFE") (such as Teflon.TM.), polyimide, hydrogel, heparin,
therapeutic drugs (such as beta-adrenergic antagonists and other
anti-glaucoma drugs, or antibiotics), and the like.
[0056] The device facilitates the outflow of aqueous from the
anterior chamber 20 into Schlemm's canal 22, and subsequently into
the aqueous collectors and the aqueous veins so that the
intraocular pressure is reduced. In one embodiment, as shown in
FIG. 3, the device 31 comprises an inlet section 2, a middle
section 4, and an outlet section 9. The middle section 4 may be an
extension of, or may be coextensive with, the inner section. The
device 31 further comprises at least one lumen within, one, two, or
all three sections 2, 4, 9 for transmitting aqueous humor from the
inlet opening 3.
[0057] In some embodiments, a curved and/or flexible outlet section
9 is positioned inside one of the natural outflow pathways. The
outlet section 9 may have a first outlet end 6 and a second,
opposite outlet end 5. The outlet section 9 may further have at
least one vent or opening 7 at one outlet end of the outlet section
9, and/or a plurality of side openings 77, for transmitting aqueous
humor. The middle section 4 is connected to or coextensive with the
outlet section 9 between the first outlet end 6 and the second
outlet end 5. In a preferred arrangement, the outlet section 9 is
curved around a point, or curve center, and the middle section
extends substantially along a plane that contains the curve center.
In one embodiment, the radius of the curve of the outlet section 9
is between about 4 mm and about 10 mm.
[0058] The device is preferably biocompatible so that any
inflammation caused by irritation between the outer surface of the
device and surrounding tissue is minimal. All or a portion of the
cross-section of one or more lumens may be in an elliptical (e.g.,
oval) shape. Furthermore, the outlet section inside the outflow
pathway may have an appropriate shape, e.g., with a protuberance or
barb projecting from it, to stabilize the device in place without
undue suturing.
[0059] In some embodiments, the radius of the curve of the outlet
section 9 is between about 4 mm and 10 mm.
[0060] An optional ridge or flange 8 at the junction of the inlet
section 2 and the middle section 4 may be provided for device
stabilization purposes. The appropriate length of the middle
section 2 that is adjacent to the ridge 8 and the outlet section 9
is, in one embodiment, preferably close in thickness to the
trabecular meshwork 21, which is approximately between about 100
microns and about 300 microns thick.
[0061] The shape of the opening 7 of the outlet section 6 and the
remaining body of the outlet section 9 may be oval, round, or other
appropriate shape. The shape in some embodiments preferably
conforms to the shape of the outflow pathway into which the outlet
section 9 is placed. The opening 7 of the outlet end may be ovoid
in shape to match the contour of Schlemm's canal 22. Further, an
outer contour of the outlet section 9 may be elliptical (e.g.,
ovoid) in shape to match the contour of Schlemm's canal 22. This
minimizes rotational movement of the outlet section 6 within
Schlemm's canal 22, and thereby stabilizes the inlet section 2 with
respect to the iris and cornea.
[0062] FIG. 4 shows another embodiment of the glaucoma device
according to principles of the present invention. The device 31A
comprises an inlet section 2A, a middle section 4A, and an outlet
section 9A. The outlet section 9A may have a first outlet end 6A
and a second, opposite outlet end 5A. The device further comprises
at least one lumen inside the glaucoma device 31A throughout one or
more of the three sections 2A, 4A, 9A for transmitting aqueous
humor starting from the inlet opening 3A. A curved and/or flexible
outlet section 9A is used for positioning the outlet section 9A
inside one of the existing outflow pathways. The outlet section 9A
may comprise an elongated trough 7A or groove for transmitting, or
venting, aqueous humor. The elongated trough is connected to and in
communication with the at least one lumen inside the glaucoma
device as shown in FIG. 4. An optional ridge 8A at the junction of
the inlet section 2A and the middle section 4A is provided for
stabilization purposes.
[0063] As shown in FIGS. 3 and 4, the device of the present
invention may have a length between about 0.5 mm to over ten
centimeters, depending on the distance between the anterior chamber
and drainage vessel (e.g., a vein) into which the device drains
aqueous humor. The outside diameter of the device may range from
about 30 .mu.m to about 500 .mu.m. The diameter of the device lumen
is advantageously in the range of about 20 .mu.m to about 250
.mu.m. The device may have a plurality of lumens to facilitate
transmission of multiple flows of aqueous humor. The long axis of
the inlet section 2, 2A may be at an angle (.theta.) between about
20 degrees and about 150 degrees, preferably between about 30 and
about 60 degrees, with respect to the long axis of the middle
section 4, 4A.
[0064] The glaucoma device of the present invention, which may also
be called a trabecular shunt, may be made by molding,
thermo-forming, or other micro-machining techniques. Biomaterial
suitable for the manufacturing the device may include polyvinyl
alcohol, polyvinyl pyrolidone, collagen, heparinized collagen,
polytetrafluoroethylene, expanded polytetrafluoroethylene,
fluorinated polymer, fluorinated elastomer, flexible fused silica,
polyolefin, polyester, polysilison, and/or a mixture of the above
biocompatible materials.
[0065] FIG. 5A illustrates a step in deploying the glaucoma device
through the trabecular meshwork 21. The outlet section 9 of the
device 31 is, in one aspect of the invention, inserted into an
opening 61 in the trabecular meshwork 21. The slit or opening 61
may be created ab interno from the interior surface 65 of the
trabecular meshwork 21. The surgeon then advances the first outlet
end 6 of the outlet section 9 through the opening 61 into a first
side of Schlemm's canal or other suitable outflow pathway. The
surgeon then advances the second outlet end 5 of the outlet section
9 through the opening 61 and into a second side of Schlemm's canal.
This may be facilitated by slightly pushing the second outlet end 5
through the opening 61. FIG. 6 illustrates a further stage in
deployment of the device, wherein the whole outlet section 9 of the
device 31 is inside the outflow pathway (e.g., Schlemm's canal),
beneath the trabecular meshwork 21. An enhanced fluid communication
through the trabecular meshwork 21 at this stage is through the
lumen of the implanted device 31.
[0066] FIG. 5B, shows an additional and/or alternate step of
deploying the glaucoma device. The surgeon can insert a distal end
63 of a guidewire 64 through the opening 61 into the first side
Schlemm's canal, or other outflow pathway, to guide the device 31
into position during the device implantation. The step of advancing
the first outlet end 6 of the outlet section 9 into Schlemm's canal
is accomplished, in this embodiment, by "riding," or advancing, the
glaucoma device 31 on the guidewire 64. A cross-section of the
guidewire may advantageously be selected from any of the following:
an elliptical (e.g., oval) shape, D-shape, round shape, and
irregular (asymmetric) shape adapted for nonrotatory engagement for
the device.
[0067] FIG. 7 shows an aspect of placing the glaucoma device at the
implantation site. An irrigating knife or applicator 51 is
provided, which, in some embodiments, comprises a syringe portion
54 and a cannula portion 55. The distal section of the cannula
portion 55 has at least one irrigating hole 53 and a distal space
56 for holding the device 31. The proximal end 57 of the lumen of
the distal space 56 is, in one embodiment, sealed off from, and
thus substantially not in communication with, the remaining lumen
of the cannula portion 55. In this embodiment, the device is placed
on the delivery applicator and advanced to the device site, wherein
the delivery applicator holds the device securely during delivery
and releases it when the surgeon chooses to deploy the device.
[0068] In some embodiments of trabecular meshwork surgery in
accordance with the invention, the patient is placed in the supine
position, prepped, draped, and anesthetized as necessary. In one
embodiment, a small (less than 1-mm incision, which may be
self-sealing, is made through the cornea. Through this incision,
the trabecular meshwork 21 is accessed, and an incision is made in
the trabecular meshwork 21 with an irrigating knife. The device 31
is then advanced through the corneal incision 52 across the
anterior chamber 20, while the device is held in an irrigating
applicator 51, under gonioscopic, microscopic, or endoscopic
guidance. After the device is implanted in place, the applicator is
withdrawn and the surgery concluded. The irrigating knife may be
within a size range of about 16 to about 40 gauge, and, in some
embodiments, preferably about 30 gauge.
[0069] FIG. 8 illustrates the device 31 positioned within the
tissue of an eye 10. An opening is present in the trabecular
meshwork 21. The outlet section 9 of the device 31 has been
inserted into the opening. The inlet section 2 is exposed to the
anterior chamber 20, while the outlet section 9 is positioned near
an interior surface 43 of the trabecular meshwork 21. In a further
embodiment, the outlet section 9 may further be placed into fluid
collection channels, as described above. A device as shown in FIG.
4, wherein the outflow section has an open trough for stenting
purposes, may be used to maintain the opening of one or more of
these outflow pathways,
[0070] In one embodiment, the method of forming an opening in the
trabecular meshwork 21 may comprise making an incision with a
microknife, a pointed guidewire, a sharpened applicator, a
screw-shaped applicator, an irrigating applicator, or a barbed
applicator. Alternatively, the trabecular meshwork 21 may be
dissected with an instrument similar to a retinal pick or
microcurrette. The opening may alternately be created by fiberoptic
laser ablation.
[0071] FIG. 9 is a close-up view of the inlet section 2 of the
glaucoma device 31, having a flow-restricting member 72 inside a
lumen 78 of the glaucoma device. The flow-restricting member 72 is
shown located close to the inlet side 71 of the inlet section 2.
Alternatively, the flow-restricting member may be situated in any
location in the device that will cause the flow of blood to be
restricted from moving retrograde, i.e., from the outlet section 9
to the anterior chamber 20 of the eye. The flow-restricting member
is used to selectively restrict at least one component in blood
from backflowing into the anterior chamber 20. The flow-restricting
member may, in some embodiments, be a filter made of a type of
material selected from the following filter materials: expanded
polytetrafluoroethylene, cellulose, ceramic, glass, Nylon, plastic,
and fluorinated material such as polyvinylidene fluoride ("PVDF")
(trade name: Kynar, by DuPont). Advantageously, the
flow-restricting member 72 tightly occupies a section of the flow
lumen 78 of the at least one lumen between the inlet section 2 and
the outlet section 9.
[0072] From the foregoing description, it will be appreciated that
a novel approach for the surgical treatment of glaucoma has been
disclosed. While aspects of the invention have been described with
reference to specific embodiments, the description is illustrative
and is not intended to limit the scope of the invention. Various
modifications and applications of the invention may occur to those
who are skilled in the art, without departing from the true spirit
or scope of the invention. The breadth and scope of the invention
should be defined only in accordance with the appended claims and
their equivalents.
* * * * *