Title: Punctum plugs having fluid collecting recesses and methods of punctal occlusion
Abstract: A punctum plug includes a distal tip, a proximal cap and a body connecting the tip to the cap. The cap has a proximal surface which remains exposed in the eye upon implantation of the punctum plug. A passage for an insertion tool extends distally in the punctum plug from an opening along the proximal surface. One or more recesses in the proximal surface collect tear fluid by surface tension, and each recess is laterally offset in its entirety from the opening and does not overlap or align with the opening. The number of recesses is indicative of the size of the punctum plug. A method of punctal occlusion involves collecting tear fluid in the one or more recesses and adhering the tear fluid in the one or more recesses by surface tension.
Patent Number: 6,994,684 Issued on 02/07/2006 to Murray, et al.
| Inventors:
|
Murray; George W. (Germantown, TN);
Watermeier; Michael J. (Memphis, TN)
|
| Assignee:
|
AlphaMed Inc. (El Paso, TX)
|
| Appl. No.:
|
461684 |
| Filed:
|
June 16, 2003 |
| Current U.S. Class: |
604/8; 604/294; 623/23.64; 606/108 |
| Current Intern'l Class: |
A61M 5/00 (20060101); A61M 35/00 (20060101); A61F 2/04 (20060101); A61F 11/00 (20060101) |
| Field of Search: |
604/8- 10,500,521,19,27,28,264,294,298,289-290,540-541,523,317,285,907
66/107-108,185,167,191,109
623/111.1,41,236.4,237.1
128/887
|
References Cited [Referenced By]
U.S. Patent Documents
| 3949750 | Apr., 1976 | Freeman.
| |
| 4660546 | Apr., 1987 | Herrick et al.
| |
| 4915684 | Apr., 1990 | MacKeen et al.
| |
| 4955896 | Sep., 1990 | Freeman.
| |
| 4959048 | Sep., 1990 | Seder et al.
| |
| 5049142 | Sep., 1991 | Herrick et al.
| |
| 5163959 | Nov., 1992 | Herrick.
| |
| 5171270 | Dec., 1992 | Herrick.
| |
| 5283063 | Feb., 1994 | Freeman.
| |
| 5334137 | Aug., 1994 | Freeman.
| |
| 5417651 | May., 1995 | Guena et al.
| |
| 5423777 | Jun., 1995 | Tajiri et al.
| |
| 5723005 | Mar., 1998 | Herrick.
| |
| 5741292 | Apr., 1998 | Mendius.
| |
| 5830171 | Nov., 1998 | Wallace.
| |
| 6016806 | Jan., 2000 | Webb.
| |
| 6027470 | Feb., 2000 | Mendius.
| |
| 6041785 | Mar., 2000 | Webb.
| |
| 6149684 | Nov., 2000 | Herrick.
| |
| 6234175 | May., 2001 | Zhou et al.
| |
| 6290684 | Sep., 2001 | Herrick.
| |
| 6306114 | Oct., 2001 | Freeman et al.
| |
| 6344047 | Feb., 2002 | Price et al.
| |
| 6527780 | Mar., 2003 | Wallace et al.
| |
Primary Examiner: Bianco; Patricia
Attorney, Agent or Firm: D'Ambrosio & Associates, P.L.L.C.
Claims
What is claimed is:
1. A punctum plug for implantation in the lacrimal drainage system of the eye, comprising
a proximal cap having a proximal surface and a distal surface;
a distal tip;
a body connecting said cap to said tip, said distal tip being insertable through
the punctal opening of the lacrimal drainage system and into the canalicular canal
communicating with the punctal opening to seat said cap on the punctal opening
with said proximal surface exposed in the eye; and
one or more recesses in said proximal surface each having a center laterally
offset from a central longitudinal axis of said punctum plug for retaining tear fluid.
2. The punctum plug recited in claim 1 wherein said cap is of a size to occlude
the punctal opening.
3. The punctum plug recited in claim 2 wherein said cap is of a size to prevent
passage of said cap through the punctal opening.
4. The punctum plug recited in claim 1 wherein said tip comprises an anchor to
resist withdrawal from the canalicular canal.
5. The punctum plug recited in claim 1 wherein each of said one or more recesses
has a periphery of partial circular configuration along said proximal surface.
6. The punctum plug recited in claim 1 wherein each of said one or more recesses
has a periphery of circular configuration along said proximal surface.
7. The punctum plug recited in claim 1 wherein said one or more recesses comprises
one to four recesses.
8. A punctum plug for implantation in the lacrimal drainage system of the eye, comprising
a proximal cap having a proximal surface and a distal surface;
a distal tip;
a body connecting said cap to said tip, said distal tip being insertable through
the punctal opening of the lacrimal drainage system and into the canalicular canal
communicating with the punctal opening to seat said cap on the punctal opening
with said proximal surface exposed in the eye;
a passage in said punctum plug for releasable engagement with an insertion tool,
said passage having an opening along said proximal surface; and
one or more recesses in said proximal surface for retaining tear fluid, each
of said one or more recesses having a periphery along said proximal surface and
a floor joined to said proximal surface along said periphery, the entire area within
said periphery being enclosed by said floor.
9. The punctum plug recited in claim 8 wherein said passage is coaxial with a
central longitudinal axis of said punctum plug and each of said one or more recesses
has a center laterally offset from said central longitudinal axis.
10. The punctum plug recited in claim 8 wherein said passage terminates in said tip.
11. The punctum plug recited in claim 8 wherein said punctum plug is made from
a medically acceptable silicone rubber.
12. The punctum plug recited in claim 8 wherein each of said one or more recesses
has a depth of about 0.001 inch.
13. The punctum plug recited in claim 8 wherein said opening has a perimeter
along said proximal surface and said periphery of each of said one or more recesses
is disposed in its entirety outside of said perimeter.
14. A punctum plug for implantation in the lacrimal drainage system of the eye, comprising
a proximal cap having a proximal surface and a distal surface;
a distal tip;
a body connecting said cap to said tip, said tip being insertable through the
punctal opening of the lacrimal drainage system and into the canalicular canal
communicating with the punctal opening to seat said cap on the punctal opening
with said proximal surface exposed in the eye; and
one or more recesses in said proximal surface, the number of said recesses in
said proximal surface corresponding to a size of said punctum plug.
15. The punctum plug recited in claim 14 wherein said number of said recesses
is one recess where said punctum plug is a first size, said number of said recesses
is two recesses where said punctum plug is a second size, different from said first
size, said number of said recesses is three recesses where said punctum plug is
a third size, different from said first size and said second size, and said number
of said recesses is four recesses where said punctum plug is a fourth size, different
from said first size, said second size and said third size.
16. The punctum plug recited in claim 15 wherein said first size is smaller than
said second size, said second size is smaller than said third size and said third
size is smaller than said fourth size.
17. The punctum plug recited in claim 14 and further including a passage in said
punctum plug coaxial with a central longitudinal axis of said punctum plug, said
passage having an opening along said proximal surface, wherein each of said one
or more recesses is separate and distinct from said opening.
18. A method of punctal occlusion for the lacrimal drainage system of the eye,
comprising the steps of
releasably engaging an insertion tool in an insertion passage of a punctum plug
having a distal tip, a proximal cap and a body connecting the distal to the proximal
cap with the insertion passage extending distally in the punctum plug from an opening
along a proximal surface of the cap;
introducing the distal tip in a punctal opening of the lacrimal drainage system;
advancing the punctum plug in the punctal opening to anchor the tip in the canalicular
canal communicating with the punctal opening and to seat the cap on the punctal
opening with the proximal surface exposed in the eye;
disengaging the insertion tool from the opening and withdrawing the insertion
tool from the eye;
leaving the punctum plug in place to block drainage of tear fluid from the eye;
collecting tear fluid in one or more recesses in the proximal surface in which
the entirety of each recess is non-overlapping with the opening; and
adhering the tear fluid in the one or more recesses by surface tension.
19. The method recited in claim 18 wherein said step of leaving includes anchoring
the punctum plug in place via engagement of the tip with the anatomical wall of
the canalicular canal.
20. The method recited in claim 18 wherein said step of advancing includes limiting
advancement of the punctum plug via engagement of the cap with an anatomical rim
of the punctal opening.
21. The method recited in claim 18 and further including, subsequent to said
step of leaving, the steps of visualizing the proximal surface exposed in the eye,
noting the number of the one or more recesses in the proximal surface and identifying
the size of the punctum plug from the number of the recesses.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the treatment of tear fluid deficiencies
in the eye and, more particularly, to punctum plugs and methods of punctal occlusion
for deterring the drainage of tear fluid from the eye.
2. Brief Discussion of the Related Art
Normally the eye is protected and lubricated by a film of naturally produced
tear fluid spread over the corneal and conjunctival epithelia through blinking.
Various problems may arise in the eye, however, where the quantity of tear fluid
in the eye is deficient, and such problems may be referred to generally as dry
eye syndrome. Tear fluid deficiencies are oftentimes chronic and may result from
inadequate tear fluid production and/or drainage of too much tear fluid from the
eye through the lacrimal drainage system of the eye. Various conditions may cause
and/or aggravate tear fluid deficiencies including disease, inflammation, congenital
defects, side effects of over-the-counter and prescription drugs, environmental
irritants or effects, atrophy, aging, eye strain, and procedures performed on the
eye such as Lasik and cataract procedures.
Dry eye syndrome is increasing in prevalence and it is estimated that up to 40%
of the U.S. population suffers from dry eye syndrome to some extent. Dry eye syndrome
may manifest as various ophthalmic ailments including itchy, gritty, sticky and/or
burning sensations, conjunctivitis, blepharitis, contact lens problems, corneal
erosion, incipient corneal graft rejection, recurrent chalzion, pinguecula, corneal
ulcers and acute lid abscesses. Sinus ailments, hay fevers, colds and other recurrent
infections have been attributed to dry eye syndrome.
One common treatment for dry eye syndrome involves the introduction of artificial
tear fluid into the eye. The benefits derived from artificial tear fluids are limited
and are usually of short duration. In some users, artificial tear fluids have caused
toxic reactions. Other drawbacks of artificial tear fluids include possible blurred
vision and unsightly deposits on the eyelids.
Mechanical devices such as punctum plugs which block or occlude the puncta
to deter drainage of tear fluid from the eye have been proposed and are represented
by U.S. Pat. Nos. 3,949,750 and 5,283,063 to Freeman, U.S. Pat. No. 4,915,684 to
MacKeen et al, U.S. Pat. No. 4,959,048 to Seder et al, U.S. Pat. Nos. 5,723,005,
6,149,684 and 6,290,684 B1 to Herrick, U.S. Pat. No. 5,417,651 to Guena et al,
U.S. Pat. No. 5,423,777 to Tajiri et al, U.S. Pat. Nos. 5,741,292 and 6,027,470
to Mendius, U.S. Pat. No. 5,830,171 to Wallace, U.S. Pat. Nos. 6,016,806 and 6,041,785
to Webb, U.S. Pat. No. 6,234,175 B1 to Zhou et al, U.S. Pat. No. 6,306,114 B1 to
Freeman et al, and U.S. Pat. No. 6,344,047 B1 to Price et al.
Punctum plugs typically include a proximal head, a distal tip and a shaft
connecting the proximal head and the distal tip. The shaft is often smaller in
cross-sectional size than the proximal head and the distal tip. A punctum plug
is usually inserted, distal tip first, in a punctal opening of the punctum and
is advanced distally in the punctum until the proximal head is seated on the punctal
opening. The proximal head is normally larger than the punctal opening such that
the proximal head does not pass through the punctal opening and remains exposed
in the eye. The distal tip typically has a cross-sectional size to fill the canalicular
canal which is in communication with the punctal opening and to anchor the punctum
plug in place. Usually the proximal head overlaps and is in abutment with a rim
of anatomical tissue circumscribing the punctal opening. The blockage or occlusion
presented by the punctum plug deters tear fluid from draining from the eye through
the punctal opening and the corresponding canalicular canal from which tear fluid
would otherwise drain into the lacrimal sac and through the nasolacrimal duct into
the nasal cavity.
Typically, punctum plugs are implanted in the eye using insertion tools,
and punctum plugs having axial passages for releasably engaging the insertion tools
to facilitate or guide implantation have been proposed as represented by U.S. Pat.
No. 3,949,750 to Freeman, U.S. Pat. No. 4,915,684 to MacKeen et al, U.S. Pat. No.
5,171,270 to Herrick, U.S. Pat. Nos. 5,283,063 and 5,334,137 to Freeman, U.S. Pat.
No. 5,423,777 to Tajiri et al, U.S. Pat. No. 5,723,005 to Herrick, U.S. Pat. Nos.
5,741,292 and 6,027,470 to Mendius, U.S. Pat. No. 5,830,171 to Wallace, U.S. Pat.
No. 6,016,806 to Webb, U.S. Pat. No. 6,149,684 to Herrick, U.S. Pat. No. 6,306,114
B1 to Freeman et al, and U.S. Pat. No. 6,344,047 B1 to Price et al, and U.S. Pat.
No. 6,527,780 B1 to Wallace et al.
The proximal heads of the punctum plugs remaining exposed in the eye may be engaged
with the insertion tools or other instruments by which the punctum plugs may be
withdrawn from the punctal openings for removal from the eye. The proximal heads
thusly enhance the ease with which punctum plugs may be implanted in and removed
from the eye and enable greater patient comfort and safety during implantation
and removal. Furthermore, the proximal heads facilitate proper positioning of the
punctum plugs in the eye and inhibit displacement of the punctum plugs by preventing
the punctum plugs from being advanced too far in the puncta. Disadvantageously,
however, the exposed proximal heads of conventional punctum plugs may cause corneal
irritation and/or lid sensation in patients, resulting in discomfort and/or intolerance
for many patients. Attempts have been made to avoid corneal irritation and/or lid
sensation by reducing the profile or thickness of the proximal heads; however,
structural strength and integrity are thereby sacrificed. The axial passages of
conventional punctum plugs are not useful to retain tear fluid on the proximal
heads of the punctum plugs for exposure in the eye due to the axial passages being
of appreciable length.
Intracanalicular implants have been proposed which are disposed
entirely within the canalicular canal without exposure or protrusion thereof in
the eye, and such implants are illustrated by U.S. Pat. Nos. 4,660,546, 5,049,142
and 5,053,030 to Herrick et al and U.S. Pat. Nos. 5,163,959 and 5,171,270 to Herrick.
Intracanalicular implants which are disposed entirely within the canalicular canal
are more difficult to implant and remove and are more likely to be implanted improperly
or to become displaced in the canalicular canal.
Conventional punctum plugs may be made available in different sizes
corresponding to anatomical puncta and canaliculi of different cross-sectional
sizes. Since the anatomical puncta and canaliculi are of microscopic size, punctum
plugs are also of microscopic size. Consequently, it is very difficult to distinguish
between different size punctum plugs, and it is particularly difficult to visually
ascertain the size of a punctum plug while implanted in the eye.
Accordingly, there is a need for a punctum plug having a proximal head
or cap which remains exposed in the eye following implantation of the punctum plug
while reducing the potential for corneal irritation and/or lid sensation from the
exposed cap. A need exists for a punctum plug having a cap which retains tear fluid
thereon for wetting the cornea when the cap is exposed in the eye after implantation
of the punctum plug in the eye. There is also a need for a punctum plug in which
tear fluid is collected in and adheres to a cap of the punctum plug via surface
tension of the tear fluid in one or more shallow recesses of the cap. Another need
exists for a punctum plug that enables size identification of the punctum plug
to be accomplished through visualization of a cap of the punctum plug while the
punctum plug is or is not implanted in the eye.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to overcome the
aforementioned disadvantages of prior punctum plugs and methods of punctal occlusion.
Another object of the present invention is to reduce the potential for corneal
irritation and/or lid sensation in patients with implanted punctum plugs having
caps exposed in the eye.
A further object of the present invention is to improve eye comfort in patients
with implanted punctum plugs having caps exposed in the eye.
It is also an object of the present invention to increase patient tolerance for
punctum plugs having caps which remain exposed in the eye.
The present invention has as an additional object to retain tear fluid on a cap
of a punctum plug for enhanced wetting of the cornea when the cap remains exposed
in the eye after implantation of the punctum plug in the eye.
An additional object of the present invention is to collect and adhere tear fluid
in a cap of a punctum plug by surface tension of the tear fluid in one or more
shallow recesses of the cap.
Yet another object of the present invention is to enable size identification
of a punctum plug through visualization of a cap of the punctum plug while the
punctum plug is or is not implanted in the eye.
The present invention also has as an object to permit visual size identification
of an implanted punctum plug without removing the punctum plug from the eye.
Still a further object of the present invention is to enable size identification
of a punctum plug from the number of recesses in a cap of the punctum plug.
The aforesaid objects are achieved individually and in combination, and it is
not intended that the present invention be construed as requiring two or more of
the objects to be combined unless expressly required by the claims attached hereto.
Some of the advantages of the present invention are that a greater number of
patients can be treated for dry eye syndrome by punctal occlusion with greater
patient comfort and tolerance; greater patient comfort and tolerance are achieved
without sacrificing structural integrity ans strength of the punctum plugs; various
insertion tools or instruments can be used to implant the punctum plugs in and
remove the punctum plugs from the eye; the caps of the punctum plugs facilitate
proper implantation and inhibit displacement of the punctum plugs by ensuring the
punctum plugs are inserted to the proper depth; the caps facilitate proper placement
of the punctum plugs by abutment with the anatomical tissue circumscribing the
punctal openings; the caps provide accessible structure for promoting engagement
of the punctum plugs with insertion tools or instruments for implantation and/or
removal of the punctum plugs from the eye; the punctum plugs can be implanted and
removed without trauma to patients; the distal tips of the punctum plugs promote
advancement of the punctum plugs during implantation and inhibit withdrawal of
the punctum plugs after implantation; the punctum plugs can be economically manufactured
of medically acceptable silicon rubber; the number of recesses in the caps of the
punctum plugs may vary; the geometric configuration of the recesses may vary; the
one or more recesses may be arranged on the caps in various ways; tear fluid collected
by the recesses is maintained close to the cornea for more effective wetting of
the corneal surface; the punctum plugs can be safely implanted in and removed from
patients' eyes as office procedures performed by trained eye technicians or eye
care medical professionals; implantation and removal are safe and pain free for
patients; the punctum plugs can be economically produced using various manufacturing
processes and equipment; and the punctum plugs can remain implanted for various
lengths of time.
These and other objects, advantages and benefits are realized with the present
invention as generally characterized in a punctum plug for implantation in the
lacrimal drainage system of the eye. The punctum plug comprises a distal tip, a
proximal cap and a body connecting the distal tip to the proximal cap. The distal
tip comprises an anchor having a configuration facilitating advancement of the
punctum plug in a punctal opening of the lacrimal drainage system and into the
canalicular canal communicating with the punctal opening. The anchor has a configuration
to apply force or pressure against the anatomical wall of the canalicular canal
to resist removal or withdrawal of the punctum plug. The cap seats over the punctal
opening when the punctum plug is implanted and blocks or occludes the punctal opening
to prevent or inhibit drainage of tear fluid through the punctal opening from the
eye. A proximal surface of the cap remains exposed in the eye when the punctum
plug is implanted, and the cap abuts anatomical tissue circumscribing the punctal
opening to ensure insertion of the punctum plug to the proper depth. The punctum
plug comprises an insertion passage for releasably engagement with an insertion
tool, the passage extending in the distal direction from an opening along the proximal
surface. One or more fluid collecting recesses are disposed along the proximal
surface for collecting tear fluid. Each recess has a periphery along the proximal
surface and a curved floor joined to the proximal surface along the periphery.
The floor extends below the proximal surface to a shallow depth, and the entire
area circumscribed by the periphery is enclosed by the floor. Each recess has a
center laterally offset from the central longitudinal axis of the insertion passage.
The opening of the insertion passage has a perimeter along the proximal surface,
and the perimeter is disposed in its entirety outside of the periphery of each
recess. Accordingly, each recess is laterally offset in its entirety from the opening
and does not overlap or align with the opening. The punctum plug may be made available
in different sizes with each size punctum plug having a different number of recesses.
Size identification—of a punctum plug can thusly be made visually by noting
the number of recesses in the proximal surface of the cap. Since the proximal surface
remains exposed in the eye when the punctum plug is implemented, size identification
can be accomplished while the punctum plug is implanted.
The present invention is further generally characterized in a method of punctal
occlusion involving the steps of releasably engaging an insertion tool in an insertion
passage of a punctum plug having a distal tip, a proximal cap and a body connecting
the distal tip to the proximal cap with the insertion passage extending distally
in the punctum plug from an opening along a proximal surface of the cap, introducing
the distal tip through a punctal opening, advancing the punctum plug in the punctal
opening to anchor the tip in the canalicular canal communicating with the punctal
opening and to seat the cap over the punctal opening with the proximal surface
exposed in the eye, withdrawing the insertion tool from the eye, leaving the punctum
plug in place to block drainage of tear fluid from the eye, collecting tear fluid
in one or more recesses in the proximal surface in which each of the recesses is
non-overlapping with the opening, and adhering the tear fluid in the one or more
recesses by surface tension. The step of advancing may include limiting advancement
of the punctum plug via engagement or abutment of the cap with anatomical tissue
circumscribing the punctal opening. The step of leaving may include anchoring the
punctum plug in place via engagement of the tip with the anatomical wall of the
canalicular canal. The method may further include, subsequent to the step of leaving,
the steps of visualizing the proximal surface exposed in the eye, noting the number
of recesses in the proximal surface and identifying the size of the punctum plug
from the number of recesses.
These and other objects, advantages and benefits of the present invention will
become apparent from the following description of the preferred embodiments taken
in conjunction with the accompanying drawings wherein like parts in each of the
several figures are identified by the same reference characters.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an anatomical representation of the lacrimal drainage system of the eye.
FIG. 2 is a broken side view, partly in section, of the lacrimal drainage system
with a punctum plug according to the present invention implanted therein.
FIG. 3 is a top view of the punctum plug of FIG. 2.
FIG. 4 is a side view of an alternative punctum plug according to the present invention.
FIG. 5 is a top view of the punctum plug of FIG. 4.
FIG. 6 is a side view of another alternative punctum plug according to the present invention.
FIG. 7 is a top view of the punctum plug of FIG. 6.
FIG. 8 is a side view of a further alternative punctum plug according to the
present invention.
FIG. 9 is a top view of the punctum plug of FIG. 8.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 depicts an eye
10 and its lacrimal drainage system
12.
Eye
10 comprises eyeball
14 having cornea
16. A series of
small lacrimal glands
18 spaced apart from one another above cornea
16
produce constant tears, and a large lacrimal gland
20 produces crying tears.
The cornea
16 and the inner surfaces of the eyelids are moisturized and
lubricated by tear fluid, which forms a tear film over the cornea
16. The
tear film serves to wet and lubricate the eye through a balance of an outer lipid
(oily) layer, a middle aqueous (watery) layer and an inner mucin (mucous) layer.
Tear fluid drains from the eye through the lacrimal drainage system
12 comprising
upper punctum and lower punctum having upper and lower punctal openings
24a
and
24b, respectively, communicating with respective upper and
lower canalicular canals
26a and
26b leading to lacrimal
sac
28 having nasolacrimal duct
30. The upper and lower punctal openings
24a and
24b are located at the inner corners of the
upper and lower eyelids, respectively, and are each circumscribed by a rim of anatomical
tissue. Tear fluid drains from the eye through the punctal openings
24a
and
24b, the upper and lower canalicular canals
26a
and
26b, the lacrimal sac
28 and the nasolacrimal duct
30 into the nasal cavity. The majority of tear fluid drains through the
lower punctum, the upper and lower canalicular canals
26a and
26b
comprise vertical canalicular portions
32a and
32b
extending from the punctal openings
24a and
24b,
respectively, to horizontal canalicular canal portions
34a and
34b,
respectively, extending to the lacrimal sac
28.
A punctum plug
40 according to the present invention is shown in FIGS.
2
and 3, the punctum plug
40 being depicted in FIG. 2 implanted in the lacrimal
drainage system
12 to block the drainage of tear fluid from the eye
10
via the lacrimal drainage system. The punctum plug
40 comprises a distal
tip
42, a proximal cap
44, and a body
46 connecting the tip
42 to the cap
44. The tip
42 comprises an anchor of frustoconical
configuration having a circular external cross-section continuously tapering from
a maximum external diameter at a rearward end
48 to a minimum external diameter
at a forward end
50. The rearward end
48 of tip
42 includes
a planar surface, and the forward end
50 of tip
42 includes a planar
surface parallel to the planar surface of rearward end
48. The body
46
extends longitudinally from tip
42 to cap
44 and is essentially cylindrical
in external configuration with a uniform or constant circular external cross-section
between flared forward and rearward ends
52 and
54 at which the body
is joined to the tip
42 and the cap
44, respectively. The external
cross-sectional diameter of the body
46 is less than the maximum external
diameter of tip
42. The cap
44 has a distal surface
56 joined
to the rearward end
54 of body
46 and has a proximal surface
58.
The distal surface
56 is planar about the rearward end
54 of body
46 and has a perimetrical edge
60 of circular configuration with
a diameter greater than the external cross-sectional diameter of body
46.
The proximal surface
58 is joined to the distal surface
56 at perimetrical
edge
60, which circumscribes the proximal surface and defines an external
perimeter for cap
44 and proximal surface
58. The proximal surface
58 comprises an annular border
62 along perimetrical edge
60,
the annular border
62 having a surface continuously curving from perimetrical
edge
60 to a central portion
64 of proximal surface
58. The
central portion
64 is circumscribed by the annular border
62 and
comprises a planar surface parallel to the planar surface of distal surface
56.
The tip
42, cap
44 and body
46 are concentric with one another
and coaxial with a central longitudinal axis
66 of the punctum plug.
A longitudinal passage
68 extends distally within the punctum plug
40
from proximal surface
58 to terminate within tip
42 such that the
body
46 may be considered a tube. The passage
68 is coaxial with
the central longitudinal axis
66 and has an opening
70 along proximal
surface
58, the opening
70 being disposed along the central portion
64 of proximal surface
58. The passage
68 is essentially cylindrical
in configuration with a uniform circular cross-section extending longitudinally
from a flared mouth at opening
70 to a beveled bottom
72 in tip
42.
The opening
70 has a perimeter
74 of circular geometric configuration
along central portion
64 of proximal surface
58. The passage
68
provides an insertion passage for releasably engaging a portion of an insertion
tool inserted in the passage to facilitate and guide insertion or implantation
of the punctum plug
40 in the lacrimal drainage system as explained further
below. The passage
68 also enhances the ability of body
46 to resiliently
flex or deform to the anatomical contour of the canalicular canal in which the
punctum plug is implanted.
The punctum plug
40 comprises one or more fluid collecting recesses
76
in the proximal surface
58 of cap
44 for retaining tear fluid, and
the punctum plug
40 is shown as having one recess
76. The recess
76 has a periphery
78 along proximal surface
58, the periphery
78 being disposed along the central portion
64 so as to be coplanar
with the perimeter
74 of opening
60. The entire area within or circumscribed
by periphery
78 is enclosed by a floor
80 of recess
76 which
is joined to the central portion
64 along periphery
78. The floor
80 presents a solid surface along the entire area within periphery
78
and is inwardly or concavely curved to a shallow depth below proximal surface
58
for collecting tear fluid as described further below. The periphery
78 can
have various geometric configurations and is depicted by way of example in FIG.
3 as having a partial-circular or semi-circular geometric configuration with a
straight side and a curved side joined to the straight side at rounded corners.
The recess
76 has a center or central axis
82, and the center
82
is laterally offset or spaced from the central longitudinal axis
66. The
entire periphery
78 is disposed along proximal surface
58 outside
of the perimeter
74. Accordingly, the recess
76 is not in axial communication
or alignment with the passage
68 or its opening
70 and is not axially
aligned with the central longitudinal axis
66. The entire periphery
78
and floor
80 of recess
76 are laterally offset from and do not overlap
or align with the perimeter
74 or opening
70. The recess
76
is thusly separate and distinct from the opening
70 and is not coextensive
with the opening
70.
The recess
76 can be arranged on the proximal surface
58 in various
ways. As an example, the recess
76 is arranged on the proximal surface
58
with the center
82 thereof disposed along a radial line emanating from with
the central longitudinal axis
66, with the straight side of periphery
78
perpendicular to this radial line, and with the curved side of the periphery
78
disposed closer to the axis
66 than the straight side thereof.
The punctum plug
40 is preferably made in its entirety of a biocompatible
or medically acceptable rubber such as silicone rubber. One example of a suitable
silicone rubber is NUSIL silicone of 70 durometer, and typical durometers may be
in the range of 60-70 Shore A durometer. Various manufacturing equipment and processes
may be used to fabricate the punctum plug including various micro-molding equipment
and processes such as individual compression silicone molding, liquid silicone
injection molding and multi-cavity compression molding. A virtually "flash free"
product can be produced whereby additional deflashing, trimming and handling can
be eliminated for a reduction in cost. The punctum plug
40 will typically
be supplied to medical service providers in a medically sterile condition ready
for implantation.
The punctum plug
40 is implanted in the lacrimal drainage system
12
by being inserted, tip
42 first, into a punctal opening such as lower punctal
opening
24b shown in FIGS. 1 and 2. The punctum plug
40 is
advanced distally or forwardly in the punctal opening
24b until the
cap
44 is seated on or over the punctal opening
24b and the
tip
42 is disposed in the canalicular canal
26b communicating
with the punctal opening
24b as depicted in FIG. 2. The tapered configuration
of the tip
42 promotes advancement of the punctum plug without trauma or
pain for the patient, and the tip
42 centers and aligns the punctum plug
in the canalicular canal during insertion. As shown in FIG. 2, a distal end of
an insertion tool
84 may be removably engaged in the passage
68 with
the proximal end of the insertion tool being grasped and manipulated to control
the position and movement of the punctum plug during implantation. Upon implantation
of the punctum plug
40, the insertion tool
84 is disengaged therefrom
leaving the implanted punctum plug in place in the lacrimal drainage system
12.
The punctum plug
40 is shown implanted in FIG. 2 with the distal surface
56 of cap
44 in abutment with is seated against the rim of anatomical
tissue circumscribing or surrounding the punctal opening
24b, and
the distal surface
56 is larger than the punctal opening
24b to
prevent the cap
44 from passing therethrough. The cap
44 covers the
punctal opening
24b in its entirety and blocks or occludes the punctal
opening to prevent or deter tear fluid from passing through the punctal opening
from the eye. Engagement or abutment of the cap
44 with the anatomical rim
of the punctal opening
24b limits and controls the distance that
the punctum plug
40 may be advanced during implantation so that proper implantation
is ensured. The rearward end
48 of tip
42 is of a size to forcefully
engage the anatomical wall of the canalicular canal
26b to prevent
the punctum plug
40 from moving proximally or rearwardly. Accordingly, the
punctum plug
40 is anchored or secured in place in the lacrimal drainage
system
12. Although the tip
42 is depicted as being anchored in the
vertical canalicular canal portion
32b, it should be appreciated
that the tip can extend into and/or be anchored within the horizontal canalicular
canal portion
34b. Of course, the anchoring force or pressure provided
by tip
42 on the wall of canalicular canal
26b can be overcome
when the punctum plug
40 is forcefully withdrawn from the canalicular canal
through the punctal opening
24b for removal from the eye. The body
46 may resiliently flex or deform to accommodate the anatomical contour
of the canalicular canal
26b, and the body
46 is of a cross-sectional
size to fit through the punctal opening
24b.
The recess
76 collects tear fluid of the eye and adheres the tear fluid
by surface tension of the tear fluid. The shallow depth of the recess
76
promotes collection of tear fluid for disposition along proximal surface
58
so that the collected tear fluid is exposed in the eye to provide wetting and lubrication
for the cornea
16. The wetting and lubrication provided by tear fluid collected
in recess
76 assists in keeping the cornea
16 wetted and reduces
possible lid sensation due to the cap
44 being exposed in the eye. The punctum
plug
40 provides greater comfort for the patient and increased tolerance
to the punctum plug such that the punctum plug can remain in place for longer periods
of time. Greater comfort and increased tolerance are achieved without having to
reduce the thickness or profile of the cap so that structural integrity and strength
are not sacrificed.
In a representative but not limiting embodiment of punctum plug
40, the
punctum plug has an overall length of about 0.055 inch; the tip has a length of
about 0.023 inch, a maximum external diameter of about 0.026 inch and a minimum
external diameter of about 0.005 inch; the body has a length of about 0.027 inch
and an external cross-sectional diameter of about 0.016 inch with the flared forward
and rearward ends having a radius of curvature of about 0.003 inch; the passage
has a length of about 0.040 inch and a diameter of about 0.0090 inch; the cap has
a thickness of about 0.005 inch and a perimetrical edge about 0.026 inch in diameter
with the annular border having a radius of curvature of about 0.004 inch; the perimeter
of the opening is about 0.0090 inch in diameter; the recess has a depth of about
0.001 inch; and the periphery of the recess has a major dimension of about 0.008
inch and a minor dimension of about 0.004 inch with the periphery of the recess
spaced along the proximal surface about 0.001 inch from the perimeter of the opening.
The representative dimensions for punctum plug
40 may be considered illustrative
of an "extra small" size punctum plug. As described further below, the punctum
plugs according to the present invention may be made available in different sizes
corresponding to different anatomical sizes of punctal openings and canalicular canals.
Another punctum plug according to the present invention is depicted at
140
in FIGS. 4 and 5. Punctum plug
140 is similar to punctum plug
40
and comprises distal tip
142, proximal cap
144, body
146 and
passage
168. Punctum plug
140 differs from punctum plug
40
in that the proximal surface
158 of cap
144 has two recesses
176
separate and distinct from each other and from opening
170 of passage
168.
Recesses
176 are each similar to recess
76 and have centers
182
laterally offset from the central longitudinal axis
166 of punctum plug
140. Each recess
176 has the entire area circumscribed by its periphery
178 enclosed by the floor
180 of the recess. The entire periphery
178 of each recess
176 is disposed along proximal surface
158
outside of the perimeter
174 of opening
170 along proximal surface
158. Accordingly, the entirety of each recess
176 is not coextensive
with and does not overlap the opening
170. Also, there is no overlap or
coextensiveness between the peripheries
178 of the recesses
176 themselves.
The punctum plug
140 may be of a different size than punctum plug
40.
In a representative but not limiting embodiment of punctum plug
140, the
punctum plug
140 may be a "small" size punctum plug in which the punctum
plug has an overall length of about 0.058 inch; the tip has a length of about 0.026
inch, a maximum external diameter of about 0.029 inch and a minimum external diameter
of about 0.005 inch; the body has a length of about 0.027 inch and an external
cross-sectional diameter of about 0.017 inch with the flared forward and rearward
ends having a radius of curvature of about 0.003 inch; the passage has a length
of about 0.043 inch and a diameter of about 0.0090 inch; the cap has a thickness
of about 0.005 inch and a perimetrical edge about 0.029 inch in diameter with the
annular border having a radius of curvature of about 0.005 inch; the perimeter
of the opening is about 0.0090 inch in diameter; the recesses have a depth of about
0.001 inch; and the periphery of each recess has a major dimension of about 0.008
inch and a minor dimension of about 0.004 inch with the periphery of each recess
being spaced along the proximal surface of the cap about 0.001 inch from the perimeter
of the opening. The recesses
176 are arranged on the proximal surface
158
with their centers
182 spaced 90° from one another about central axis
166.
Another alternative punctum plug according to the present invention is depicted
at
240 in FIGS. 6 and 7. Punctum plug
240 is similar to punctum plugs
40 and
140 and comprises distal tip
242, proximal cap
244,
body
246 and passage
268. Punctum plug
240 differs from punctum
plugs
40 and
140 in that the proximal surface
258 of cap
244
has three recesses
276 separate and distinct from each other and from opening
270 of passage
268. Recesses
276 are each similar to recesses
76 and
176 and have centers
282 laterally offset from the
central longitudinal axis
266 of punctum plug
240. Each recess
276
has the entire area circumscribed by its periphery
278 enclosed by the floor
280 of the recess. The entire periphery
278 of each recess
276
is disposed along proximal surface
258 outside of the perimeter
274
of opening
270 along proximal surface
258. Accordingly, the entirety
of each recess
276 is not coextensive with and does not overlap the opening
270. Also, there is no overlap or coextensiveness between the peripheries
278 of the recesses
276 themselves.
The punctum plug
240 may be of a different size than the punctum plugs
40 and
140. In a representative but not limiting embodiment of punctum
plug
240, the punctum plug
240 may be a "medium" size punctum plug
in which the punctum plug has an overall length of about 0.063 inch; the tip has
a length of about 0.031 inch, a maximum external diameter of about 0.033 inch and
a minimum external diameter of about 0.005 inch; the body has a length of about
0.027 inch and an external cross-sectional diameter of about 0.020 inch with the
flared forward and rearward ends of the body having a radius of curvature of about
0.003 inch; the passage has a length of about 0.043 inch and a diameter of about
0.0090 inch; the cap has a thickness of about 0.005 inch and a perimetrical edge
about 0.033 inch in diameter with the annular border having a radius of curvature
of about 0.005 inch; the perimeter of the opening is about 0.0090 inch; the recesses
have a depth of about 0.001 inch, a major dimension of about 0.008 inch and a minor
dimension of about 0.004 inch; and the periphery of each recess is spaced along
the proximal surface of the cap about 0.001 inch from the perimeter of the opening.
The recesses
276 are arranged on the proximal surface
258 with the
centers
282 of the recesses spaced 90 degrees from one another about the
central longitudinal axis
266.
An additional alternative punctum plug
340 according to the present invention
is illustrated in FIGS. 8 and 9. Punctum plug
340 is similar to punctum
plugs
40,
140 and
240 and comprises distal tip
342,
proximal cap
344, body
346 and passage
368. Punctum plug
340
is different from punctum plugs
40,
140 and
240 in that the
proximal surface
358 of cap
344 has four recesses
376 separate
and distinct from each other and from opening
370 of passage
368.
Recesses
376 are different from the recesses
76,
176 and
276
in that the periphery
378 of each recess
376 has a circular geometric
configuration. The centers
382 for recesses
376 are laterally offset
from the central longitudinal axis
366 of punctum plug
340. Each
recess
376 has the entire area circumscribed by its periphery
378
enclosed by the floor
380 of the recess. The entire periphery
378
of each recess
376 is disposed along proximal surface
358 outside
of the perimeter
374 of opening
370 along proximal surface
358.
Accordingly, there is no overlap or coextensiveness between the opening
370
and the recesses
376. Also, there is no overlap or coextensiveness between
the peripheries
378 of the recesses
376 themselves.
The punctum plug
340 may be of a different size than the punctum plugs
40,
140 and
240. In a representative but not limiting embodiment
of punctum plug
340, the punctum plug
340 may be a "large" size punctum
plug in which the punctum plug has an overall length of about 0.069 inch; the tip
has a length of about 0.037 inch, a maximum external diameter of about 0.037 inch
and a minimum external diameter of about 0.005 inch; the body has a length of about
0.027 inch and an external cross-sectional diameter of about 0.022 inch with the
flared forward and rearward ends of the body having a radius of curvature of about
0.003 inch; the passage has a length of about 0.043 inch and a diameter of about
0.0090 inch; the cap has a thickness of about 0.005 inch and a perimetrical edge
about 0.037 inch in diameter with the annular border having a radius of curvature
of about 0.005 inch; the perimeter of the opening is about 0.0090 inch; the recesses
have a depth of about 0.001 inch and a diameter of about 0.008 inch; and the periphery
of each recess is spaced along the proximal surface of the cap about 0.001 inch
from the perimeter of the opening. The recesses
376 are arranged on the
proximal surface
358 with the centers
382 of the recesses spaced
90° from one another about the central longitudinal axis
366.
Punctum plugs
40,
140,
240, and
340 are microscopically
sized in accordance with the microscopic size of the anatomical puncta and canaliculi.
The punctum plugs
40,
140,
240 and
340 have first,
second, third and fourth sizes, respectively, corresponding to different anatomical
sizes of puncta and canaliculi. A punctum plug of the appropriate size can be thusly
selected for implantation in the lacrimal drainage system of a patient's eye based
upon the particular anatomical characteristics of the patient's lacrimal drainage
system. Given the very small sizes of the punctum plugs, it is difficult to visually
distinguish between different size punctum plugs. In the punctum plugs
40,
140,
240 and
340, the number of recesses
76,
176,
276 and
376, respectively, correspond to and are indicative of the
size of the punctum plugs. More particularly, one recess in the proximal surface
of the cap of the punctum plug identifies the punctum plug as an "extra small"
size punctum plug; two recesses in the proximal surface of the cap of the punctum
plug identifies the punctum plug as a "small" size punctum plug; three recess in
the proximal surface of the cap of the punctum plug identifies the punctum plug
as a "medium" size punctum plug; and four recesses in the proximal surface of the
cap of the punctum plug identifies the punctum plug as a "large" size punctum plug.
The size of a punctum plug can thusly be identified or ascertained visually merely
by viewing the cap of the punctum plug, as typically assisted with microscopic
magnification, and noting the number of recesses in the cap. The size of a punctum
plug can be determined in this manner prior or subsequent to implantation in that
subsequent to implantation the exposed cap of the punctum plug can be visualized
microscopically while the punctum plug remains implanted.
With the punctum plugs of the present invention, tear fluid is retained in the
fluid collecting recesses of the caps to assist in keeping the corneal surface
wetted and to reduce possible lid sensation from exposure of the caps in the eye.
Tear fluid is collected in and adheres to the recesses by surface tension of the
tear fluid with the silicone rubber (LSR) from which the punctum plugs are made.
Tear fluid is collected along the proximal surfaces of the caps so as to be exposed
in the eye for enhanced wetting and lubrication. The number of recesses in the
caps allow the size of the punctum plugs to be identified visually, and the size
of an implanted punctum plug can be visually identified by noting the number of
recesses without removing the implanted punctum plug from the eye.
The distal tips can have various external configurations and/or external cross-sections
to facilitate advancement of the punctum plugs during implantation and to resist
withdrawal of the punctum plugs following implantation. The perimetrical edges
the caps can have various geometric configurations to provide occlusion of the
punctum while preventing passage of the caps through the punctal openings. The
caps may be designed so that the caps are partly disposed within the punctal opening
upon implantation. The bodies can have various external cross-sectional configurations
which may be uniform or constant along the length of the bodies or non-uniform
or non-constant along the length of the bodies. The passages can have various cross-sectional
configurations depending on the configuration of the insertion tools, and the passage
cross-sections can be uniform or non-uniform along the length of the passages.
The length of the passages can vary depending on the length of the insertion tools
to be engaged with the passages. The perimeters of the passage openings on the
proximal surfaces of the caps can have various configurations. The peripheries
of the recesses can have various geometric configurations including, but not limited
to, semi-circular, partial-circular, circular, square, rectangular, triangular,
quadrangular, trapezoidal, oval and elliptical configurations. The recesses can
be arranged on the proximal surfaces in various ways.
Inasmuch as the present invention is subject to many variations, modifications
and changes in detail, it is intended that all subject matter discussed above or
shown in the accompanying drawings be interpreted as illustrative only and not
be taken in a limiting sense.
*
