U.S. patent application number 15/635988 was filed with the patent office on 2017-10-19 for methods and systems for treating meibomian gland dysfunction using radio-frequency energy.
The applicant listed for this patent is TearScience, Inc.. Invention is credited to Steven Bacich, Benjamin Tyson Gravely, Stephen M. Grenon, Donald R. Korb, Timothy R. Willis.
Application Number | 20170299567 15/635988 |
Document ID | / |
Family ID | 47424798 |
Filed Date | 2017-10-19 |
United States Patent
Application |
20170299567 |
Kind Code |
A1 |
Korb; Donald R. ; et
al. |
October 19, 2017 |
METHODS AND SYSTEMS FOR TREATING MEIBOMIAN GLAND DYSFUNCTION USING
RADIO-FREQUENCY ENERGY
Abstract
A method of treating meibomian gland dysfunction is disclosed.
The method includes directing RF energy to an internal portion of a
meibomian gland, selectively targeting an obstruction within a duct
of the meibomian gland with the applied RF energy to melt, loosen,
or soften the obstruction, and expressing the obstruction from the
duct of the meibomian gland. An apparatus for treating meibomian
gland dysfunction is also disclosed. The apparatus comprises at
least one RF electrode configured to direct RF energy to an
internal portion of a meibomian gland located in an eyelid of an
eye, the at least one RF electrode further configured to
selectively target an obstruction within a duct of the meibomian
gland with the applied RF energy to melt, loosen, or soften the
obstruction. The apparatus also comprises at least one expressor
configured to express the obstruction from the duct of the
meibomian gland.
Inventors: |
Korb; Donald R.; (Boston,
MA) ; Grenon; Stephen M.; (Durham, NC) ;
Willis; Timothy R.; (Raleigh, NC) ; Gravely; Benjamin
Tyson; (Raleigh, NC) ; Bacich; Steven; (Half
Moon Bay, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TearScience, Inc. |
Morrisville |
NC |
US |
|
|
Family ID: |
47424798 |
Appl. No.: |
15/635988 |
Filed: |
June 28, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13590828 |
Aug 21, 2012 |
9719977 |
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15635988 |
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PCT/US12/44650 |
Jun 28, 2012 |
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13590828 |
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11434033 |
May 15, 2006 |
8915253 |
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13590828 |
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11931398 |
Oct 31, 2007 |
9060843 |
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13590828 |
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11434033 |
May 15, 2006 |
8915253 |
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11931398 |
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13242068 |
Sep 23, 2011 |
8685073 |
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13590828 |
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12821183 |
Jun 23, 2010 |
8025689 |
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13242068 |
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11434054 |
May 15, 2006 |
8083787 |
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12821183 |
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13183901 |
Jul 15, 2011 |
9216028 |
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13590828 |
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11541418 |
Sep 29, 2006 |
7981145 |
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13183901 |
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11541308 |
Sep 29, 2006 |
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13590828 |
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11893669 |
Aug 17, 2007 |
8255039 |
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11541308 |
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12015593 |
Jan 17, 2008 |
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11893669 |
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61502120 |
Jun 28, 2011 |
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60700233 |
Jul 18, 2005 |
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60700233 |
Jul 18, 2005 |
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60880850 |
Jan 17, 2007 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2018/046 20130101;
A61N 1/403 20130101; Y10T 436/206664 20150115; A61H 2201/5043
20130101; A61H 9/0071 20130101; A61F 2007/0004 20130101; A61H
9/0057 20130101; G01N 33/227 20130101; A61H 7/005 20130101; A61H
23/0263 20130101; A61B 18/12 20130101; A61B 5/4836 20130101; Y10T
436/178459 20150115; A61H 23/0236 20130101; A61N 7/00 20130101;
A61H 39/086 20130101; A61H 9/0078 20130101; Y10T 436/19 20150115;
A61F 9/00718 20130101; Y10T 436/173845 20150115; A61H 2201/0176
20130101; Y10T 436/170769 20150115; A61B 2562/0247 20130101; A61H
2015/0014 20130101; A61H 2201/0207 20130101; Y10T 436/173076
20150115; A61H 2201/5038 20130101; A61F 9/007 20130101; A61F
2007/0059 20130101; A61B 2018/048 20130101; A61H 23/0245 20130101;
A61H 2201/0214 20130101; A61H 7/003 20130101; A61H 2205/024
20130101; A61B 2562/0271 20130101 |
International
Class: |
G01N 33/22 20060101
G01N033/22; A61F 9/007 20060101 A61F009/007; A61F 9/007 20060101
A61F009/007; A61H 7/00 20060101 A61H007/00; A61H 7/00 20060101
A61H007/00; A61H 9/00 20060101 A61H009/00; A61H 9/00 20060101
A61H009/00; A61H 9/00 20060101 A61H009/00; A61H 23/02 20060101
A61H023/02; A61H 23/02 20060101 A61H023/02; A61H 23/02 20060101
A61H023/02; A61N 1/40 20060101 A61N001/40 |
Claims
1. A method of treating meibomian gland dysfunction, comprising the
steps of: positioning a first RF electrode proximate an inner
surface of an eyelid containing at least one meibomian gland;
positioning a second RF electrode proximate an external surface of
the eyelid; directing RF energy via at least one of the first RF
electrode and the second RF electrode to an internal portion of a
meibomian gland; selectively targeting an obstruction within a duct
of the meibomian gland with the applied RF energy to melt, loosen,
or soften the obstruction; and expressing the obstruction from the
duct of the meibomian gland.
2. The method of claim 1, further comprising directing the RF
energy until an increase in thermal energy occurs at the
obstruction in the duct.
3. The method of claim 1, wherein the selectively targeting further
comprises directing RF energy waveforms such the RF energy
waveforms are absorbed preferentially by energy absorbing cellular
fluids, saline or lipid containing materials found in the duct of
the meibomian gland.
4. The method of claim 1, wherein the selectively targeting further
comprises directing RF energy at a predetermined depth in the
meibomian gland.
5. The method of claim 1, wherein the applied RF energy causes
contents within the duct of the meibomian gland to be heated to
between 37 and 45 degrees Celsius.
6. The method of claim 1, further comprising controlling the amount
of RF energy applied to an internal portion of a meibomian
gland.
7. The method of claim 6, wherein the controlling further comprises
directing an amount of RF energy sufficient to selectively heat
contents within the duct of the meibomian gland to a known
temperature.
8. The method of claim 1, further comprising adjusting a power
and/or a duration of the RF energy.
9. The method of claim 1, further comprising adjusting a shape of a
waveform of the RF energy.
10. The method of claim 1, further comprising providing pulsed
waveforms of RF energy.
11. The method of claim 1, further adjusting a shape of an RF
electrode that applies the RF energy.
12. The method of claim 1, further comprising monitoring a
temperature at a surface of the eyelid.
13. An apparatus for treating meibomian gland dysfunction
comprising: a first RF electrode configured to be positioned
proximate an inner surface of an eyelid containing at least one
meibomian gland; a second RF electrode configured to be positioned
proximate an external surface of the eyelid; an energy delivery
source configured to direct RF energy via at least one of the first
RF electrode and second RF electrode to an internal portion of a
meibomian gland to selectively target an obstruction within a duct
of the meibomian gland with the applied RF energy to melt, loosen,
or soften the obstruction; and at least one expressor configured to
express the obstruction from the duct of the meibomian gland.
14. The apparatus of claim 13, further comprising an eyecup
configured to prevent RF energy from being delivered to sensitive
structures of an eye.
15. The apparatus of claim 14, wherein the eyecup further comprises
an inner sandwich.
16. The apparatus of claim 14, wherein the eyecup further comprises
a conductive plate on the eyecup.
17. The apparatus of claim 14, wherein at least a portion of the
eyecup is used as a backplate for expression of the
obstruction.
18. The apparatus of claim 13, further comprising an aspiration
means.
19. The apparatus of claim 14, further comprising at least one
gutter structure disposed on the eyecup.
20. The apparatus of claim 13, further comprising an insulator.
21. The apparatus of claim 13, further comprising a cooling
mechanism.
22. The apparatus of claim 13, further comprising a spacer
configured to keep the at least one RF electrode from touching an
eyelid.
23. The apparatus of claim 13, wherein at least one of the first RF
electrode and the second RF electrode is used as a backplate for
expression of the obstruction.
24. The apparatus of claim 13, wherein at least one of the first RF
electrode and the second RF electrode is adjustable to express the
obstruction.
25. The apparatus of claim 13, wherein the at least one expressor
comprises a roller.
26. The apparatus of claim 13, further comprising an aspiration
means configured to be positioned on an inner eyelid surface to
help express the obstruction from the duct of the meibomian
gland.
27. The apparatus of claim 13, further comprising a means for
applying vibrational or ultrasonic energy to loosen the obstruction
from the duct of the meibomian gland.
28. The apparatus of claim 13, further comprising an energy
generator configured to direct RF energy via both the first RF
electrode and the second RF electrode to an internal portion of a
meibomian gland to selectively target an obstruction within a duct
of the meibomian gland with the applied RF energy to melt, loosen,
or soften the obstruction.
29. The apparatus of claim 18, further comprising a conduit
operably connected to the aspiration means that is configured
withdraw expressed material from the glands.
30. The apparatus of claim 18, further comprising a mesh screen
positioned at one or more orifices of the meibomian gland through
which the aspiration means extracts the obstructions from within
the duct of the meibomian gland.
31. The apparatus of claim 19, wherein the at least one gutter
structure focuses a vacuum or aspiration force provided by an
aspiration means.
32. The apparatus of claim 19, wherein the at least gutter
structure is further configured to facilitate drug delivery.
33. The apparatus of claim 29, wherein the conduit is further
configured to deliver fluid intermittently to the eyelid to help
improve transport of the expressed obstructions.
34. The apparatus of claim 29, wherein the conduit is further
configured to administer a topical agents and/or drugs to the
meibomian glands.
Description
RELATED APPLICATIONS
[0001] The present application is a continuation of, and claims
priority to, co-pending U.S. patent application Ser. No. 13/590,828
entitled "Methods and Systems for Treating Meibomian Gland
Dysfunction Using Radio-Frequency Energy," filed Aug. 21, 2012,
which in turn is a continuation of PCT Application No.
PCT/US12/44650 entitled "Methods and Systems for Treating Meibomian
Gland Dysfunction Using Radio-Frequency Energy," filed Jun. 28,
2012, which claims priority to U.S. Provisional Patent Application
No. 61/502,120 entitled "Method and Systems for Treating Meibomian
Gland Dysfunction Using Radio-Frequency Energy," filed Jun. 28,
2011, all of which are incorporated herein by reference in their
entireties.
[0002] In addition, co-pending U.S. patent application Ser. No.
13/590,828 entitled "Methods and Systems for Treating Meibomian
Gland Dysfunction Using Radio-Frequency Energy," filed Aug. 21,
2012, to which this application claims priority, is a
continuation-in-part patent application of each of the following
applications, all of which are incorporated herein by reference in
their entireties:
[0003] U.S. application Ser. No. 11/434,033 entitled "Method and
Apparatus for Treating Gland Dysfunction Employing Heated Medium,"
filed on May 15, 2006, which claims priority to U.S. Provisional
Patent Application No. 60/700,233, entitled "Method and Apparatus
for Treating Gland Dysfunction," filed Jul. 18, 2005;
[0004] U.S. application Ser. No. 11/931,398 entitled "Method and
Apparatus for Treating Gland Dysfunction Employing Heated Medium,"
filed on Oct. 31, 2007, which claims priority to U.S. application
Ser. No. 11/434,033 entitled "Method and Apparatus for Treating
Gland Dysfunction Employing Heated Medium," filed on May 15, 2006,
which claims priority to U.S. Provisional Patent Application No.
60/700,233, entitled "Method and Apparatus for Treating Gland
Dysfunction," filed Jul. 18, 2005;
[0005] U.S. application Ser. No. 13/242,068 entitled "Apparatus for
Treating Meibomian Gland Dysfunction," filed on Sep. 23, 2011,
which claims priority to U.S. application Ser. No. 12/821,183
entitled "Method and Apparatus for Treating Meibomian Gland
Dysfunction," filed on Jun. 23, 2010, which claims priority to U.S.
application Ser. No. 11/434,054 entitled "Method and Apparatus for
Treating Meibomian Gland Dysfunction," filed on May 15, 2006;
[0006] U.S. application Ser. No. 13/183,901 entitled "Apparatuses
for Treatment of Meibomian Glands," filed on Jul. 15, 2011, which
claims priority to U.S. application Ser. No. 11/541,418 entitled
"Treatment of Meibomian Glands," filed on Sep. 29, 2006;
[0007] U.S. application Ser. No. 11/541,308 entitled "Melting
Meibomian Gland Obstructions," filed on Sep. 29, 2006;
[0008] U.S. application Ser. No. 11/893,669 entitled "Meibomian
Gland Illuminating and Imaging," filed on Aug. 17, 2007; and
[0009] U.S. application Ser. No. 12/015,593 entitled "Apparatus for
Inner Eyelid Treatment of Meibomian Gland Dysfunction," filed on
Jan. 17, 2008, which claims priority to U.S. Provisional Patent
Application No. 60/880,850 entitled "Method and Apparatus for
Treating Meibomian Gland Obstructive Disease," filed on Jan. 17,
2007.
FIELD OF THE DISCLOSURE
[0010] The field of the disclosure relates to treatment of
meibomian gland dysfunction (MGD), which may be either responsible
for or be a contributing factor to a patient suffering from a "dry
eye" condition. A patient's meibomian glands are treated to aid in
facilitating a sufficient protective lipid layer being generated
and retained on the tear film of the eye to retain aqueous.
BACKGROUND
[0011] In the human eye, the tear film covering the ocular surfaces
is composed of three layers. The innermost layer in contact with
the ocular surface is the mucus layer. The mucus layer is comprised
of many mucins. The middle layer comprising the bulk of the tear
film is the aqueous layer. The aqueous layer is important in that
it provides a protective layer and lubrication to prevent dryness
of the eye. Dryness of the eye can cause symptoms such as
itchiness, burning, and irritation, which can result in discomfort.
The outermost layer is comprised of many lipids known as "meibum"
or "sebum." This outermost lipid layer is very thin, typically less
than 250 nm in thickness. The lipid layer provides a protective
coating over the aqueous and mucus layers to limit the rate at
which these underlying layers evaporate. A higher rate of
evaporation of the aqueous layer can cause dryness of the eye.
Thus, if the lipid layer is not sufficient to limit the rate of
evaporation of the aqueous layer, dryness of the eye may result.
The lipid layer also lubricates the eyelid during blinking, which
prevents dry eye. Dryness of the eye is a recognized ocular
disease, which is generally known as "dry eye." If the lipid layer
can be improved, the rate of evaporation is decreased, lubrication
is improved, and partial or complete relief of the dry eye state is
achieved.
[0012] The sebum that forms the outermost lipid layer is secreted
by meibomian glands 10 of the eye, as illustrated in FIGS. 1 and 2
of this application. The meibomian glands are enlarged, specialized
sebaceous-type glands (hence, the use of "sebum" to describe the
secretion) located on both the upper eyelid 12 and lower eyelid 14.
The meibomian glands contain orifices 16 that are designed to
discharge lipid secretions onto the lid margins, thus forming the
lipid layer of the tear film as the mammal blinks and spreads the
lipid secretion. The typical human upper eyelid 12 has about twenty
five (25) meibomian glands and the lower eyelid 14 has about twenty
(20) meibomian glands, which are somewhat larger than those located
in the upper lid. Blinking and the squeezing action of the muscle
of Riolan surrounding the meibomian glands 10 are thought to be the
primary mechanism to open the orifice for the release of secretion
from the meibomian gland 10. The meibomian gland orifices 16 open
on the lid margin usually along the mucocutaneous junction also
known as the gray line. The meibomian gland orifices 16 are assumed
to open with blinking and release minute amounts of sebum
secretions onto the lid margin and then into the inferior tear
meniscus. The lipid "sebum" in the tear meniscus is spread upward
and over the tear film of the open eye by the upward blink action.
Blinking causes the upper lid 12 to pull a sheet of the lipids
secreted by the meibomian glands 10 over the other two layers of
the tear film, thus forming a type of protective coating which
limits the rate at which the underlying layers evaporate. If the
lipid secretions are optimal, and adequate lipid layer is
maintained at the air interface, evaporation is minimized and dry
eye states are prevented. If the lipid secretions are inadequate,
the lipid layer is not adequate to minimize evaporation with
resulting rapid evaporation leading to dry eye states. Thus, a
defective lipid layer or an insufficient quantity of such lipids
can result in accelerated evaporation of the aqueous layer which,
in turn, causes symptoms such as itchiness, burning, irritation,
and dryness, which are collectively referred to as "dry eye."
[0013] Various treatment modalities have been developed to treat
the dry eye condition. These modalities include drops, which are
intended to replicate and replace the natural aqueous tear film and
pharmaceuticals which are intended to stimulate the tear producing
cells. For example, eye drops such as Refresh Endura.TM.,
Soothe.TM., and Systane.TM. brand eye drops are designed to closely
replicate the naturally occurring healthy tear film. However, their
use and administration are merely a treatment of symptoms and not
of the underlying cause. Further, the use of aqueous drops is
generally for an indefinite length of time and consequently,
extended use can become burdensome and costly.
[0014] Pharmaceutical modalities, such as the use of tetracycline,
have also been suggested to treat meibomian gland dysfunction. One
such treatment is disclosed in U.S. Patent Application Publication
No. 2003/0114426 entitled "Method for Treating Meibomian Gland
Disease," U.S. Pat. No. 6,455,583 entitled "Method for Treating
Meibomian Gland Disease" to Pflugfelder et al., and PCT Publication
Application No. WO 99/58131 entitled "Use of Tetracyclines for
Treating Meibomian Gland Disease." However, this treatment has not
proven to be universally clinically effective, and it may be
unnecessary in cases where MGD is the result of obstruction of the
gland without infection.
[0015] The use of corticosteroids has also been proposed to treat
MGD as disclosed in U.S. Pat. No. 6,153,607 entitled "Non-preserved
Topical Corticosteroid for Treatment of Dry Eye, filamentary
Keratitis, and Delayed Tear Clearance (or Turnover)" to Pflugfelder
et al. Again, this proposed treatment appears to treat the symptoms
of dry eye, as opposed to treatment of the underlying cause.
[0016] Additionally, the use of topically applied androgens or
androgen analogues has also been used to treat acute dry eye signs
and symptoms in keratoconjunctivitis sicca. This is disclosed in
U.S. Pat. Nos. 5,958,912 and 6,107,289, both entitled "Ocular
Therapy in Keratoconjunctivitis Sicca Using Topically Applied
Androgens or TGF-beta." and both issued to Sullivan.
[0017] There is a correlation between the tear film lipid layer and
dry eye disease. The various different medical conditions and
damage to the eye and the relationship of the lipid layer to those
conditions are reviewed in Surv Opthalmol 52:369-374, 2007. It is
clear that the lipid layer condition has the greatest effect on dry
eye disease when compared to the aqueous layer or other causes.
Thus, while dry eye states have many etiologies, the inability of
the meibomian gland 10 to sufficiently generate the lipid layer is
a common cause of common dry eye state. This state is the condition
known as "meibomian gland dysfunction" (MGD). MGD is a disorder
where the meibomian glands 10 are obstructed or occluded. As
employed herein the terms "occluded" and "obstruction" as they
relate to meibomian gland dysfunction are defined as partially or
completely blocked or plugged meibomian glands. If completely
obstructed the gland cannot secrete. If partially or intermittently
occluded the gland may secrete either normal or decreased amounts
of sebum. More usually the secretions are altered having
semi-solid, thickened, congested secretions, frequently described
as inspissated. The secretions may be clear or yellowish, the
latter indicating possible infection. Meibomitis, an inflammation
of the meibomian glands leading to their dysfunction, is usually
accompanied by blepharitis (inflammation of the lids). Meibomian
gland dysfunction may accompany meibomitis, or meibomian gland
dysfunction may be present without obvious lid inflammation.
[0018] MGD is frequently the result of keratotic obstructions,
which partially or completely block the meibomian gland orifices
16. Such obstructions compromise the secretory functions of the
individual meibomian glands 10. More particularly, these keratotic
obstructions may be associated with or result in various
combinations of bacteria, sebaceous ground substance, dead, and/or
desquamated epithelial cells (see, Meibomian Gland Dysfunction and
Contact Lens Intolerance, Journal of the Optometric Association,
Vol. 51, No. 3, Korb et al., (1980), pp. 243-51).
[0019] Hormonal changes, which occur during menopause and
particularly changing estrogen levels, can result in thickening of
the oils secreted by the meibomian glands 10. This may result in
clogged gland orifices. Further, decreased estrogen levels may also
enhance conditions under which staphylococcal bacteria can
proliferate. This can cause migration of the bacteria into the
glands 10 compromising glandular function and further contributing
to occlusion, thus resulting in a decreased secretion rate of the
meibomian gland 10.
[0020] When the flow of secretions from the meibomian gland 10 is
restricted due to the existence of an occlusion, cells on the
eyelid margin have been observed to grow over the gland orifice 16.
This may further restrict sebum flow and exacerbate a dry eye
condition. Additional factors may also cause or exacerbate
meibomian gland dysfunction including age, disorders of blinking,
activities such as computer use which compromise normal blinking,
contact lens use, contact lens hygiene, cosmetic use, or other
illness, particularly diabetes. The state of an individual
meibomian gland 10 can vary from optimal, where clear meibomian
fluid is produced; to mild or moderate meibomian gland dysfunction
where milky fluid or inspissated or creamy secretion is produced;
to total blockage, where no secretion of any sort can be obtained
(see "Increase in Tear Film Lipid Layer Thickness Following
Treatment of Meibomian Gland Dysfunction," Lacrimal Gland, Tear
Film, and Dry Eye Syndromes," Korb, et al., pp. 293-98, Edited by
D. A. Sullivan, Plenum Press, New York (1994)). Significant
chemical changes of the meibomian gland 10 secretions occur with
meibomian gland dysfunction and consequently, the composition of
the naturally occurring tear film is altered, which in turn,
contributes to dry eye.
[0021] MGD may be difficult to diagnose, because visible indicators
are not always present. For example, meibomitis, an inflammation of
the meibomian glands 10, can lead to MGD. Meibomitis may also be
accompanied by blepharitis (inflammation of the lids). While
meibomitis is obvious by inspection of the external lids, MGD may
not be obvious even when examined with the magnification of the
slit-lamp biomicroscope. This is because there may not be external
signs or the external signs may be so minimal that they are
overlooked. The external signs of MGD without obvious lid
inflammation may be limited to subtle alterations of the meibomian
gland orifices 16, overgrowth of epithelium over the orifices 16,
and pouting of the orifices 16 of the glands 10 with congealed
material acting as obstructions. In severe instances of MGD without
obvious lid inflammation, the changes may be obvious, including
serrated or undulated lid margins, orifice recession and more
obvious overgrowth of epithelium over the orifices 16, and pouting
of the orifices 16.
[0022] Thus to summarize, the meibomian glands 10 of mammalian
(e.g., human) eyelids secrete oils that prevent evaporation of the
tear film and provide lubrication to the eye and eyelids. These
glands can become blocked or plugged (occluded) by various
mechanisms leading to so-called "dry eye syndrome." While not the
only cause, MGD is a known cause of dry eye syndrome. The disorder
is characterized by a blockage of some sort at an orifice of the
meibomian glands 10 preventing normal lipid secretions from flowing
from the meibomian glands 10 to form the lipid layer of the tear
film. Such secretions serve to prevent evaporation of the aqueous
tear film and lubricate the eye and eyelids 12, 14, hence, their
absence can cause dry eye syndrome.
[0023] While the present state of the art provides a number of
treatments for dry eye, there is a need to treat the underlying
cause, as opposed to the symptom. Many patients suffer from dry eye
as a result of obstructions or occlusions in the meibomian glands.
Thus, a need exists to provide effective treatment of the meibomian
glands to restore a sufficient flow of sebum to the lipid layer of
the eye to limit the rate of evaporation of the underlying
layers.
SUMMARY OF THE DETAILED DESCRIPTION
[0024] It is herein recognized that, in addition to obstructions at
an orifice of a meibomian gland, obstructions located within a
meibomian gland channel (duct) below the orifice, can also be a
cause of lipid layer deficiency in a tear film that could lead to
evaporative dry eye MGD. It is further recognized that obstructions
within the meibomian gland channel causing lipid layer deficiency
may not be obvious to detect, because MGD may be present without
obvious lid inflammation, as opposed to clogged meibomian gland
orifices, where meibomitis is present and obvious by inspection of
the external eyelids. Thus, regardless of whether a clogged
meibomian gland orifice is recognized by the presence of meibomitis
and unclogged as part of a treatment to remove bacterial flora that
reside at the eyelid margin, if an obstruction is located within
the meibomian gland channel (duct), the obstruction may not be
detected. As a result, secretions from the meibomian gland may
still not flow in order to be added to the tear film upon blinking,
regardless of whether a meibomian gland orifice is unclogged. Thus,
the inventors of the present application recognized that removing
obstructions from within a channel or duct of the meibomian gland
would be beneficial for treating MGD.
[0025] In this regard, embodiments disclosed herein include methods
and systems for treating meibomian gland dysfunction. In one
embodiment, a method is provided and comprises directing RF energy
to an internal portion of a meibomian gland, selectively targeting
an obstruction within a duct of the meibomian gland with the
applied RF energy to melt, loosen, or soften the obstruction, and
expressing the obstruction from the duct of the meibomian gland.
Embodiments disclosed herein can use RF or microwave energy to
soften obstructions in the internal portions of the meibomian
glands to treat meibomian gland dysfunction (MGD). Using RF or
microwave energy may allow an efficient heat transfer to the
meibomian gland duct to be attained, which may allow higher
temperatures to be attained at the meibomian glands and/or in a
more efficient time to melt, loosen, or soften more serious
obstructions or occlusions in the meibomian glands. RF energy may
allow heightened temperatures at the meibomian glands to be
attained and in less time when applying heat to the outside of the
eyelid due to more effective conductive heat transfer and the
proximity of the heating to the eyelid surface.
[0026] In another embodiment, an apparatus for treating meibomian
gland dysfunction is disclosed. The apparatus comprises at least
one RF electrode configured to direct RF energy to an internal
portion of a meibomian gland located in an eyelid of an eye, the at
least one RF electrode further configured to selectively target an
obstruction within a duct of the meibomian gland with the applied
RF energy to melt, loosen, or soften the obstruction. The apparatus
also comprises at least one mechanical expressor configured to
express the obstruction from the duct of the meibomian gland.
[0027] In another embodiment, a method of treating meibomian gland
dysfunction is disclosed. The method comprising positioning an RF
electrode proximate an external surface of an eyelid containing at
least one meibomian gland, directing RF energy via the RF electrode
to an internal portion of a meibomian gland, selectively targeting
an obstruction within a duct of the meibomian gland with the
applied RF energy to melt, loosen, or soften the obstruction; and
expressing the obstruction from the duct of the meibomian
gland.
[0028] The methods may be performed by apparatuses according to
embodiments disclosed herein. In one example, such an apparatus may
comprise an RF electrode configured to be positioned proximate an
external surface of an eyelid containing at least one meibomian
gland. The apparatus may also comprises an energy delivery source
configured to direct RF energy via the RF electrode to an internal
portion of a meibomian gland to selectively target an obstruction
within a duct of the meibomian gland with the applied RF energy to
melt, loosen, or soften the obstruction. At least one mechanical
expressor configured to express the obstruction from the duct of
the meibomian gland is also included in the apparatus.
[0029] In another embodiment, a method of treating meibomian gland
dysfunction is disclosed. The method comprising positioning an RF
electrode proximate an internal surface of an eyelid containing at
least one meibomian gland, directing RF energy via the RF electrode
to an internal portion of a meibomian gland, selectively targeting
an obstruction within a duct of the meibomian gland with the
applied RF energy to melt, loosen, or soften the obstruction; and
expressing the obstruction from the duct of the meibomian
gland.
[0030] The above method may be performed by an apparatus according
to one embodiment. The apparatus comprises an RF electrode
configured to be positioned proximate an internal surface of an
eyelid containing at least one meibomian gland. The apparatus also
comprises an energy delivery source configured to direct RF energy
via the RF electrode to an internal portion of a meibomian gland to
selectively target an obstruction within a duct of the meibomian
gland with the applied RF energy to melt, loosen, or soften the
obstruction. At least one mechanical expressor configured to
express the obstruction from the duct of the meibomian gland is
also included in the apparatus.
[0031] In another embodiment, a method of treating meibomian gland
dysfunction is disclosed that uses a plurality of RF electrodes.
The method comprises positioning a first RF electrode proximate an
inner surface of an eyelid containing at least one meibomian gland
and positioning a second RF electrode proximate an external surface
of the eyelid. RF energy is then applied via at least one of the
first RF electrode and the second RF electrode to an internal
portion of a meibomian gland. An obstruction within a duct of the
meibomian gland is selectively targeted with the applied RF energy
to melt, loosen, or soften the obstruction, and the softened
obstruction is then expressed from the duct of the meibomian
gland.
[0032] The method described above may be performed using an
apparatus according to another embodiment. The apparatus comprises
a first RF electrode configured to be positioned proximate an inner
surface of an eyelid containing at least one meibomian gland and a
second RF electrode configured to be positioned proximate an
external surface of the eyelid. The apparatus further includes an
energy delivery source configured to direct RF energy via at least
one of the first RF electrode and second RF electrode to an
internal portion of a meibomian gland to selectively target an
obstruction within a duct of the meibomian gland with the applied
RF energy to melt, loosen, or soften the obstruction. At least one
expressor configured to express the obstruction from the duct of
the meibomian gland is also included.
[0033] In another embodiment, a method of treating meibomian gland
dysfunction is disclosed. The method includes applying a topical
agent to an eyelid having at least one meibomian gland. An eyecup
is then positioned on a globe of an eye and the eyelid is placed on
a positioning pad. An energy delivery device is positioned
proximate the positioning pad and energy is applied to the eyelid
via the energy delivery device to soften an obstruction in the
meibomian gland. The softened obstruction is then aspirated from
the meibomian gland.
[0034] In another embodiment, after expression of the occlusions or
obstructions is performed, an optional pharmacological agent may be
applied to the meibomian gland to promote the free flow of sebum
and/or reduce or prevent inflammation or infections of the eye or
eyelids. Many pharmacological agents have been proposed for
treatment of dry eye syndrome, any of which may be effective or
more effective upon clearing of obstructions within the meibomian
glands. Some of the pharmacological agents that may be utilized
include, but are not limited to: antibiotics such as topical or
oral tetracycline and chemically modified tetracycline,
testosterone, topical or oral corticosteroids, topical androgens or
androgen analogues, omega 3 fatty acid compounds such as fish oils,
Laennec, enzymes that promote lipid production, agents that
stimulate production of enzymes that promote lipid production,
and/or any agent which acts as a secretagogue to enhance meibomian
gland secretion or secretion of other tear components. For example,
androgen and androgen analogues and TGF-beta have been reported to
act as a secretagogue to enhance meibomian gland secretion.
[0035] These compounds are illustrative examples of appropriate
pharmacological agents, but those skilled in the art will
appreciate that other pharmacological compounds may be
utilized.
[0036] Also, agents, such as Restasis (cyclosporine A), that
replace or promote production of the tear component may also be
applied more effectively after treating the meibomian glands
according to one or more of the embodiments disclosed herein.
Treating the meibomian glands improves the lipid layer thus
reducing evaporation and conserving the aqueous layer. Conservation
of the aqueous layer reduces the need for tear substitutes to be
applied through tear component agents. Thus, tear component agents
may not have to be used as often when employing the embodiments
disclosed herein to treat a patient's MGD.
[0037] In addition, convective heat losses occur due to blood flow
in the blood vessels located inside the eyelid. Blood flow through
blood vessels located inside the eyelid produces convective heat
losses. The blood flow serves as a natural "heat sink" provided by
the body. Convective heat loss is lessened when directing RF energy
to the internal portions of the meibomian gland within the eyelid
than when applying heat to the outside of the eyelid. This is
because fewer blood vessels are located between the meibomian
glands and the inside of the eyelid than the outside of the eyelid.
The meibomian glands are located closer to the inside of the
eyelid. Moreover, it was discovered that if the blood flow was
reduced, convective heat losses could be minimized allowing for
temperatures to be attained and sustained at the meibomian glands
in an even more efficient manner and in less time.
[0038] Thus, one embodiment also includes the further application
of force to the patient's eyelid in addition to RF energy. The
application of force can further assist in obtaining higher
temperatures more efficiently inside the eyelid at the palpebral
conjunctiva and at the meibomian gland in a shorter period of time
and thus more efficiently. This is because the application of force
may reduce blood flow to the eyelid to reduce convective heat loss,
as discussed above.
[0039] Applying force can also result in a more efficient
conductive heat transfer from an applied RF energy source, because
the pressure created by the force causes the RF energy source to be
compressed against the tissue of the eyelid. This compression can
have several benefits. Compression spreads out the tissue to which
heating is applied thus making it thinner and improving conductive
heat transfer. Compression can also "squeeze out" air pockets at
the surface of the eyelid due to the microscopic roughness of skin.
Thus, compression of the RF energy source against the eyelid
increases the surface contact between the RF energy source and the
surface of the eyelid (which increases the heat transfer equation)
to provide a more effective conductive heat transfer to the
meibomian glands. This results in the meibomian glands being heated
to the desired temperature level in a shorter period of time due to
these gained efficiencies. Further, increased temperatures may be
attained that may not have otherwise been obtained, or obtained
using less heat or thermal energy. Because the heating is located
in close proximity to the eyelid surface and the RF energy source
is further compressed against the eyelid surface, heat transfer is
very efficient providing for the temperature at the surface of the
eyelid to be very close to the temperature at the meibomian
glands.
[0040] The applied force may be regulated, meaning that a force
generating means is controlled to be within pressure ranges that
are safe to be applied to the eyelid and at sufficient pressure to
allow the temperature at the meibomian gland to be raised
sufficiently. The force can also be a constant force and be
provided manually.
[0041] The force may be applied during, after, or both during and
after the application of the RF energy. In either case, the force
may assist in expressing occlusions or obstructions when in a
loosened, softened, or melted state from the meibomian glands. The
force may include vibratory type forces, including those generated
mechanically or those using fluid type devices or mechanisms. The
level of force needed to express obstructions or occlusions in the
glands may be greatly reduced when RF energy is applied to the
obstructions or occlusions to place them in a melted, softened, or
loosened state.
[0042] The application of force can also stimulate the movement of
fluids or suspensions of occlusions or obstructions from the
glands. Devices, which generally apply a regulated force or milking
action to the eyelid to express the fluids or suspensions or to
otherwise mechanically stimulate the movement of fluids from the
glands, may be used. In some instances, a small, gentle, continuous
force applied to the eyelid will assist in expression of the fluids
and suspensions. Vibration can also be used when applying force
simultaneously or immediately after the heating to further assist
in the expression.
[0043] Those skilled in the art will appreciate the scope of the
present invention and realize additional aspects thereof after
reading the following detailed description of the preferred
embodiments in association with the accompanying drawing
figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] The accompanying drawing figures incorporated in and forming
a part of this specification illustrate several aspects of the
disclosed embodiments, and together with the description serve to
explain the principles of the disclosed embodiments.
[0045] FIG. 1 illustrates an exemplary upper and lower human eyelid
showing the meibomian glands;
[0046] FIG. 2 illustrates an exemplary cutaway view of a meibomian
gland;
[0047] FIG. 3 illustrates an exemplary cutaway view of a meibomian
gland having a plurality of clogging mechanisms;
[0048] FIG. 4 illustrates an RF electrode for directing RF energy
to meibomian glands in an eyelid;
[0049] FIG. 5 is a flowchart illustrating an exemplary process of
directing RF energy to the eyelid relating to treating the
meibomian glands;
[0050] FIG. 6A is a perspective view of a system for clearing
obstructed meibomian glands according to an exemplary
embodiment;
[0051] FIG. 6B is a broken away side view of the probe tip employed
in the embodiment of FIG. 6A;
[0052] FIG. 7A is a perspective view of another exemplary probe
tip;
[0053] FIG. 7B is a broken away side view of the probe tip of FIG.
5;
[0054] FIG. 7C is a broken away side view of the probe tip of FIGS.
4a and 5a in place on an eyelid;
[0055] FIG. 8A is a side view of an exemplary embodiment of the
probe tip having rollers for clearing obstructed meibomian
glands;
[0056] FIG. 8B is a side view of an exemplary embodiment of a probe
tip having rollers for clearing obstructed meibomian glands on;
[0057] FIG. 9 is a side view of an exemplary embodiment of a probe
tip having rollers for clearing obstructed meibomian glands;
[0058] FIG. 10 illustrates an exemplary system for directing RF
energy from a RF generator to an RF electrode positioned proximate
an eyelid;
[0059] FIG. 11 illustrates a controller to be used with the system
of FIG. 10 for facilitating selective and controllable
communication of RF energy and/or force to the eyelid, according to
one embodiment;
[0060] FIG. 12A is a broken side view of an exemplary eyecup
comprising an exemplary RF electrode configured to direct RF energy
to the internal portions of meibomian glands according to one
embodiment;
[0061] FIG. 12B is a close up view of the exemplary eyecup of FIG.
12A showing RF energy being applied to the internal portions of
meibomian glands according to one embodiment;
[0062] FIG. 13 is a broken side view of an exemplary eyecup
comprising an exemplary cooling mechanism and an exemplary RF
electrode configured to direct RF energy to the internal portions
of meibomian glands according to one embodiment;
[0063] FIG. 14 is a broken side view of an exemplary eyecup
comprising an exemplary RF electrode located on the outside of an
eyelid configured to preferentially heat an exemplary conductive
plate located on a periphery of the exemplary eyecup;
[0064] FIG. 15 is a broken side view of an exemplary eyecup
comprising an exemplary RF electrode positioned on an outer surface
of an eyelid;
[0065] FIG. 16 illustrates an exemplary eyelid temperature profile
of an inner and outer eyelid temperature versus time when heat is
applied to the exterior of the eyelid;
[0066] FIG. 17 illustrates an exemplary eyelid lid temperature
profile of inside and outside eyelid temperature versus time when
heat is applied to the inside the eyelid;
[0067] FIG. 18 is a flowchart illustrating an exemplary process of
applying heat to the inner eyelid relating to treating meibomian
glands;
[0068] FIG. 19 illustrates an exemplary lid temperature profile of
eyelid temperature versus time when heat and force is applied to
inside the eyelid;
[0069] FIG. 20 is a flowchart illustrating an exemplary process of
applying heat to the inner eyelid with the addition of force
applied to the outside or outer surface of the eyelid relating to
treating the meibomian glands;
[0070] FIG. 21 is a broken side view of an exemplary eyecup
comprising an exemplary RF electrode positioned on an inner surface
of an eyelid;
[0071] FIG. 22 illustrates a heat and force application device
according to one embodiment to facilitate the application of heat
to the inside and force to the outside of a patient's eyelid
relating to treating meibomian glands;
[0072] FIG. 23 illustrates the process of placing a lid warmer onto
a patient's eye inside the eyelid to install a heat application
device onto a patient's eye for treating the meibomian glands,
according to one embodiment;
[0073] FIG. 24 illustrates a cross-sectional view of the lid warmer
illustrated in FIGS. 22 and 23 to further illustrate heat delivery
components and features of the lid warmer, according to one
embodiment;
[0074] FIGS. 25A and 25B illustrate embodiments of a lid warmer and
eyecup heat and force application device for securing the eyecup to
the lid warmer as part of installing the force application device
onto a patient's eye for treating the meibomian glands;
[0075] FIG. 26 illustrates a top level system diagram of the
temperature and pressure control and communication components of
the heat and force application device for selectively and
controllably communicating to the lid warmer and eyecup components
to apply heat to the inside of a patient's eyelid and/or force to
the outside of the patient's eyelid, according to one
embodiment;
[0076] FIG. 27 illustrates an interface circuit diagram for the
heating and force application device, according to one
embodiment;
[0077] FIG. 28 illustrates a cross-sectional view of an exemplary
eyecup comprising an exemplary aspiration channel for collecting
materials expressed from the meibomian glands and an exemplary
conduit for cooling media;
[0078] FIG. 29A illustrates an exemplary eyecup comprising
exemplary gutter structures configured to assist in aspirating
materials expressed from within a duct of the meibomian gland
through the orifice of the meibomian gland and to facilitate drugs
or other topical agents to an eye;
[0079] FIG. 29B is a close up view of the exemplary gutter
structures of FIG. 29 illustrating how the exemplary gutter
structures assist in pulling open the meibomian gland to assist in
expressing and collecting materials from within a duct of the
meibomian gland through the orifice of the meibomian gland;
[0080] FIG. 30 is a broken side view of an exemplary eyecup
comprising exemplary RF electrodes positioned on both an outer
surface and an inner surface of an eyelid;
[0081] FIG. 31 illustrates a thermal gradient created by the
application of RF energy via an exemplary RF electrode positioned
on an inner surface of an eyelid;
[0082] FIG. 32 is a flowchart illustrating the basic process
employed by the heat and force application device to selectively
and controllably apply heat to the inside of a patient's eyelid
and/or force to the outside of the patient's eyelid, according to
one embodiment;
[0083] FIG. 33 is a broken away side view of an exemplary apparatus
for clearing obstructed meibomian glands;
[0084] FIG. 34 is a perspective view of a suction device for
clearing glands;
[0085] FIG. 35 is a side view of another embodiment of the
apparatus for clearing meibomian glands;
[0086] FIG. 36A is a schematic view of another embodiment of the
apparatus for clearing meibomian glands;
[0087] FIG. 36B is an exploded view of the hand-held probe of the
embodiment of FIG. 36A;
[0088] FIG. 36C is a side view of the hand-held probe of FIGS. 36A
and 36B applying force to an eyelid;
[0089] FIG. 37A is a perspective view of another embodiment of the
meibomian gland treatment apparatus in the form of the
hydro-oculator;
[0090] FIG. 37B is a side view of the hydro-oculator of FIG.
37A;
[0091] FIG. 37C is a schematic side view of the hydro-oculator of
FIG. 37A in place against the lower eyelid;
[0092] FIG. 37D is a schematic side view of the hydro-oculator of
FIG. 37A in place against the lower eyelid and showing the fluid
filled bladder beginning to expand;
[0093] FIG. 37E is a schematic side view of the hydro-oculator of
FIG. 37A in place against the lower eyelid and showing the fluid
filled bladder in a further expanded state; and
[0094] FIG. 38 is a flowchart illustrating an alternate meibomian
gland treatment employing applying heat to the outside of a
patient's eyelid and force to the inside of the patient's eyelid
for treating meibomian glands.
DETAILED DESCRIPTION
[0095] The embodiments set forth below represent the necessary
information to enable those skilled in the art to practice the
invention and illustrate the best mode of practicing the invention.
Upon reading the following description in light of the accompanying
drawing figures, those skilled in the art will understand the
concepts of the invention and will recognize applications of these
concepts not particularly addressed herein. It should be understood
that these concepts and applications fall within the scope of the
disclosure and the accompanying claims.
[0096] It is herein recognized that, in addition to obstructions at
an orifice of a meibomian gland, obstructions located within a
meibomian gland channel (duct) below the orifice, can also be a
cause of lipid layer deficiency in a tear film that could lead to
evaporative dry eye MGD. It is further recognized that obstructions
within the meibomian gland channel causing lipid layer deficiency
may not be obvious to detect, because MGD may be present without
obvious lid inflammation, as opposed to clogged meibomian gland
orifices, where meibomitis is present and obvious by inspection of
the external eyelids. Thus, regardless of whether a clogged
meibomian gland orifice is recognized by the presence of meibomitis
and unclogged as part of a treatment to remove bacterial flora that
reside at the eyelid margin, if an obstruction is located within
the meibomian gland channel (duct), the obstruction may not be
detected. As a result, secretions from the meibomian gland may
still not flow in order to be added to the tear film upon blinking,
regardless of whether a meibomian gland orifice is unclogged. Thus,
the inventors of the present application recognized that removing
obstructions from within a channel or duct of the meibomian gland
would be beneficial for treating MGD.
[0097] In this regard, embodiments disclosed herein include methods
and systems for treating meibomian gland dysfunction. In one
embodiment, a method is provided and comprises directing RF energy
to an internal portion of a meibomian gland, selectively targeting
an obstruction within a duct of the meibomian gland with the
applied RF energy to melt, loosen, or soften the obstruction, and
expressing the obstruction from the duct of the meibomian gland.
Embodiments disclosed herein can use RF or microwave energy to
soften obstructions in the internal portions of the meibomian
glands to treat meibomian gland dysfunction (MGD). Using RF or
microwave energy may allow an efficient heat transfer to the
meibomian gland duct to be attained, which may allow higher
temperatures to be attained at the meibomian glands and/or in a
more efficient time to melt, loosen, or soften more serious
obstructions or occlusions in the meibomian glands. RF energy may
allow heightened temperatures at the meibomian glands to be
attained and in less time when applying heat to the outside of the
eyelid due to more effective conductive heat transfer and the
proximity of the heating to the eyelid surface.
[0098] Some patients have obstructions or occlusions in their
meibomian glands that will not sufficiently melt, loosen, or soften
to be expressed without attaining heightened temperatures at the
meibomian glands. In many instances, these temperatures either
cannot be achieved when applying conductive heat to the outside of
the eyelid, or these temperatures may be achievable, but only after
applying heat to the outside of the eyelid for a significant period
of time. Heightened temperatures may also only be achieved by
applying heat at unsafe temperatures that would either produce an
unacceptable pain response to the patient or damage to the
patient's eyelid. This is because of the temperature drop between
the outside of the eyelid and the meibomian glands due to
conductive heat loss. Heat applied to the outside of the eyelid
must conductively travel through the eyelid tissue and through the
tarsal plate that encases the meibomian glands inside the eyelid.
As an example, it may take twenty to thirty minutes for the
temperature at the meibomian glands to reach only a temperature of
41 to 42 degrees Celsius when applying heat to the outside of the
eyelid that will not burn or damage the patient's eyelid or
surrounding tissue. Temperatures may need to reach between 43 to 45
degrees Celsius, for example, for melting, loosening, or softening
of certain obstructions or occlusions in a patient's meibomian
glands.
[0099] The ability to effectively and more efficiently raise the
temperature at the meibomian glands by directing RF energy may
prove instrumental in reaching the melting, loosening, or softening
points of obstructions or occlusions. Directing RF energy can also
include directing RF energy to the meibomian glands orifices that
are located at the inner surface of the eyelid at the lid margin.
The orifices may also be obstructed or occluded. The application of
RF energy to the internal portions of the meibomian glands and
proximate or directly to the meibomian glands orifices may also
prove instrumental in restoring sufficient sebum flow for the lipid
layer.
[0100] The regulated RF energy can be maintained at a therapeutic
temperature for a treatment period. The treatment period can be
approximately 1 to 10 minutes for example. The RF energy could also
be repeatedly applied and maintained for a desired period of time
to keep the occlusion or obstruction in a melted, loosened, or
softened state. Either during or after such treatment by regulated
RF energy, mechanical expression of lipids and other fluids from
the meibomian glands has been found to clear obstructions which
have essentially melted or been placed in a suspension state (by
virtue of melting materials binding solids together).
[0101] As discussed above, in the human eye, the tear film covering
the ocular surfaces is composed of three layers. The innermost
layer in contact with the ocular surface is the mucus layer. The
mucus layer is comprised of many mucins. The middle layer
comprising the bulk of the tear film is the aqueous layer. The
aqueous layer is important in that it provides a protective layer
and lubrication to prevent dryness of the eye. Dryness of the eye
can cause symptoms such as itchiness, burning, and irritation,
which can result in discomfort. The outermost layer is comprised of
many lipids known as "meibum" or "sebum." This outermost lipid
layer is very thin, typically less than 250 nm in thickness. The
lipid layer provides a protective coating over the aqueous and
mucus layers to limit the rate at which these underlying layers
evaporate. A higher rate of evaporation of the aqueous layer can
cause dryness of the eye. Thus, if the lipid layer is not
sufficient to limit the rate of evaporation of the aqueous layer,
dryness of the eye may result. The lipid layer also lubricates the
eyelid during blinking, which prevents dry eye. Dryness of the eye
is a recognized ocular disease, which is generally known as "dry
eye." If the lipid layer can be improved, the rate of evaporation
is decreased, lubrication is improved, and partial or complete
relief of the dry eye state is achieved.
[0102] With respect to FIGS. 1 and 2, the sebum that forms the
outermost lipid layer is secreted by meibomian glands 10 of the
eye, as illustrated in FIGS. 1 and 2 of this application. The
meibomian glands are enlarged, specialized sebaceous-type glands
(hence, the use of "sebum" to describe the secretion) located on
both the upper eyelid 12 and lower eyelid 14. The meibomian glands
contain orifices 16 that are designed to discharge lipid secretions
onto the lid margins, thus forming the lipid layer of the tear film
as the mammal blinks and spreads the lipid secretion. The typical
human upper eyelid 12 has about twenty five (25) meibomian glands
and the lower eyelid 14 has about twenty (20) meibomian glands,
which are somewhat larger than those located in the upper lid. It
is known that obstructions or blockages at the orifices 16 can lead
to poor lipid secretion, which may result in dry eye.
[0103] The inventors of the present application recognized for the
first time that blockages within other parts of the meibomian
glands 10 below the orifice 16 could also prevent an adequate lipid
secretion and cause dry eye. Referring to FIG. 3, each meibomian
gland 10 has a straight long central duct 18 lined with four
epithelial layers on the inner surface of the duct 18. Along the
length of the central duct 18 are multiple lateral out-pouching
structures 20, termed acini, where the secretion of the gland is
manufactured. The inner lining of each acinus 20 differs from the
main central duct 18 in that these specialized cells provide the
secretions of the meibomian gland. The secretions flow from each
acinus 20 to the duct 18. While it has not been established with
certainty, there appears to be a valve system between each acinus
20 and the central duct 18 to retain the secretion until it is
required, at which time it is discharged into the central duct 18.
The meibomian secretion is then stored in the central duct 18 and
is released through the orifice of each gland onto the lid margin.
The inventors recognized that if these valves exist, they may also
become obstructed in some instances leading to reduced or blocked
flow from the acini 20. These obstructions or occlusions 22, 24 may
have various compositions.
[0104] FIG. 3 illustrates an example of obstructions 22, 24 or
occlusions 22, 24. Plug obstructions 22 can occur at the orifice 16
located at a top of the meibomian gland 10. Alternatively,
obstructions and occlusions 24 can occur in the central duct 18 and
may also block a particular acinus 20, as seen in FIG. 3. The
obstructions or occlusions 22, 24 can mean that the meibomian
glands 10 are partially blocked or plugged, completely blocked or
plugged, or any variation thereof. Obstructions and occlusions 22,
24 can be in a solid, semi-solid, or thickened, congealed secretion
and/or a plug, leading to a compromise, or more specifically, a
decrease in or cessation of secretion. Also, with a reduced or
limited secretion, the meibomian gland 10 may be compromised by the
occluded or obstructive condition often evidenced by a yellowish
color, indicating a possible infection state. Alternatively, the
meibomian gland 10 may be otherwise compromised so that the
resulting protective lipid film is not adequate for preventing
evaporation of the underlying layers on the eye.
[0105] MGD is frequently the result of keratotic obstructions,
which partially or completely block the meibomian gland orifices 16
and/or the central duct (canal) 18 of the gland 10, or possibly the
acini or acini valves (assuming they do in fact exist) or the
acini's junction 20 with the central duct 18. Such obstructions 22,
24 compromise the secretory functions of the individual meibomian
glands 10. More particularly, these keratotic obstructions may be
associated with or result in various combinations of bacteria,
sebaceous ground substance, dead, and/or desquamated epithelial
cells (see, Meibomian Gland Dysfunction and Contact Lens
Intolerance, Journal of the Optometric Association, Vol. 51, No. 3,
Korb et al., (1980), pp. 243-51).
[0106] Referring again to FIG. 3, obstructions or occlusions 22, 24
of the meibomian glands 10 may be present over or at the orifice 16
of the gland 10, in the main channel 18 of the gland 10, which may
be narrowed or blocked, or possibly in other locations including
the passages from the acini 20 to the main channel 18. Methods and
apparatuses disclosed herein are designed to treat MGD that is
caused by obstructions due to infection and inflammation at the
orifice of the meibomian, as well as a different type of MGD caused
by obstructions within the central duct or channel 18 of the
meibomian gland 10, or within the acini 20, or at the junction of
the acini 20 and the central duct or channel 18. This includes
loosening or removing possible obstructions or occlusions 22, 24 in
the meibomian glands 10, including the expression of obstructions
located within the central duct 18 or the acinus 20 of the
meibomian gland 10 through an orifice 16 of the meibomian gland 10.
FIG. 2 of the application shows the obstructions or occlusions 22,
24 of FIG. 3 in the meibomian glands 10 removed to restore sebum
flow to the lipid layer.
[0107] Microwave and RF energy may be utilized to pinpoint thermal
energy at specific target tissues. In addition, RF and microwave
energy can be manipulated to be absorbed or directed for a certain
type of cellular content or tissue material make up. For instance,
the RF or microwave energy waveforms can be directed to be absorbed
preferentially by energy absorbing cellular fluids, saline or lipid
containing materials found in the ducts, channels, or acini of the
meibomian glands rather than the cellular structures of the
meibomian glands themselves. Pulsed waveform energy may react more
preferentially on certain cellular fluids and contents than
continuous waveforms. Specifically for the removal of meibomian
gland obstructions, the desired temperature range for liquefying
lipid containing obstructions is quickly and easily achievable
using RF energy. Thus, in the area of removing meibomian gland
obstructions, a series of short pulsed RF energy waves or
microwaves could preferentially heat gland contents within the
eyelid without raising the temperature of surrounding tissues or
unintended tissue surfaces significantly.
[0108] Besides selectively heating different types of tissue
contents and not heating indiscriminately surrounding tissue,
microwave/RF energy can be directed to perform at a predetermined
depth as seen in hyperthermia treatments or when treating a
specific depth within the wall of the arterial vessel. For
meibomian gland obstructions, being able to treat within the duct
itself will have advantages by avoiding thermal injury to eyelid
tissue surfaces, which are in close proximity to the ducts, and the
eye, cornea, and other unintended structures that are clearly
thermally sensitive tissues.
[0109] Another important benefit with the described systems is that
RF or microwave energy can provide a very rapid direct internal
heating source. The clear advantage with this would be an overall
decrease in procedural time and reducing patient discomfort from
the procedure. In addition since the thermal energy does not
require conductive heating or a thermal gradient through tissue to
reach its intended target, theoretically terminating the procedure
could occur more quickly. Finally, for busy physician practices,
shorter procedural times will improve patient flow through the
practice.
[0110] In the current application, the desired amount of thermal
energy to deliver to contents within the meibomian glands is 45
degrees C. Microwave or RF energy can be controlled by the ESU to
selectively heat to a known temperature within the tissues and/or
selectively heat lipid containing materials by adjusting the power
and duration of the RF or microwave energy; adjusting the shape of
the waveform (stepped or curved); using pulsed or continuous
waveforms; adjusting the shape of antenna or electrode that
delivers or emits the RF or microwave energy.
[0111] As briefly mentioned herein above, obstruction composition
will vary with the etiology which produced it. However, the
obstruction will, in most cases, consist of a combination of, dead
cells, keratin, bacteria, desquamated cells, sebaceous ground
substance, milky fluid, inspissated or creamy secretions, or any
combination of the foregoing in solid, semi-solid and thickened
forms. The obstruction may be in the gland channel, at the gland
orifice, atop the gland orifice or a combination of the foregoing.
As employed herein, obstruction refers to any of the foregoing.
[0112] Thus, it is self-evident that any obstruction of the channel
will restrict or prevent secretions from exiting the gland and
further, that in order to clear such obstructions or "occlusions",
the obstruction may be loosened from the gland wall, and/or broken
up, fractured, softened, or liquefied so that it will fit through
the gland orifice without causing excessive pain. Lastly, the
obstruction remnants must be expressed from the gland. The
embodiments disclosed herein provide a method and apparatus to
accomplish these tasks.
[0113] According to one embodiment, the obstructions 22, 24 as seen
in FIG. 3 should be softened or liquefied prior to attempting
extraction or expression. With respect to the foregoing, the terms
"softened" or "liquefied" are intended to mean a "non-solid"
flowable state. In addition, in order to be clinically
satisfactory, softening or liquefying of the obstructions 22 or 24
should be effected as quickly as possible and regulated heat
treatment time should be less than five (5) minutes with one to two
(1-2) minutes being preferred without causing damage to the
surrounding tissues of the ocular globe or the eye. The heating of
the obstructions 22 or 24 may be accomplished by any number of
techniques. Many of the embodiments disclosed herein will be
discussed with RF energy being used for the heating. However, the
heat treatments can also be electrical, laser heating, hot water
conductive heating, infrared heating, ultrasonic heating, etc., in
lieu of or in addition to RF heating. The disclosed heating
treatments necessarily require the addition of a greater amount of
energy (heating) than is deliverable by the conventional
application of hot compresses which according to current practice
are applied for 3-15 minutes prior to the clinician attempting to
remove the obstruction. Once the obstruction is softened or
liquefied, removal is obtained by the application of a regulated
force to the gland. More specifically, it is contemplated by
embodiments disclosed herein that the force applied be a repeatable
controlled force, as more fully explained herein below.
[0114] In order to soften, melt, or loosen obstructions in the
meibomian glands, as discussed above, in one embodiment, thermal
energy may be applied to the obstruction 22 or 24 without
contacting the meibomian gland. In one embodiment, RF energy may be
applied to the meibomian glands 10 in order to melt, soften, or
loosen any obstructions in the meibomian glands prior to attempting
extraction or expression of the obstructions from the meibomian
glands. FIG. 4 illustrates an eye 26 having an eyelid 28, which
contains a plurality of meibomian glands 30. An RF electrode 32 is
provided for directing RF energy to the meibomian glands 30. The RF
electrode 32 may be located proximate to the eyelid 28. In one
embodiment, the RF electrode 32 does not make contact with the
eyelid 28, while in another embodiment, the RF electrode 32
slightly touches the eyelid 28. In the embodiment shown in FIG. 4,
the RF electrode 32 is positioned proximate to an outer surface of
the eyelid 28 and is configured to direct RF energy in a direction
into the eyelid, as shown by arrows 34 in FIG. 4, such that the RF
energy may selectively target the meibomian glands, and in
particular, any obstructions in the meibomian glands.
[0115] In one embodiment, in lieu of an RF electrode, a microwave
antenna configured to direct microwave energy to the internal
portions of the eyelid 28 may be used.
[0116] In this manner, RF or microwave energy may be utilized to
pinpoint thermal energy at specific target tissues. In addition, RF
and microwave energy can be manipulated to be absorbed or directed
for a certain type of cellular content or tissue material make up.
For instance, the RF or microwave energy waveforms can be directed
to be absorbed preferentially by energy absorbing cellular fluids,
saline or lipid containing materials found in the ducts, channels,
or acini of the meibomian glands rather than the cellular
structures of the meibomian glands themselves. Pulsed waveform
energy may react more preferentially on certain cellular fluids and
contents than continuous waveforms. Specifically for the removal of
meibomian gland obstructions, the desired temperature range for
liquefying lipid containing obstructions is quickly and easily
achievable using RF energy. Thus, in the area of removing meibomian
gland obstructions, a series of short pulsed RF energy waves or
microwaves could preferentially heat gland contents within the
eyelid without raising the temperature of surrounding tissues or
unintended tissue surfaces significantly.
[0117] Besides selectively heating different types of tissue
contents and not heating indiscriminately surrounding tissue,
microwave/RF energy can be directed to perform at a predetermined
depth as seen in hyperthermia treatments or when treating a
specific depth within the wall of the arterial vessel. For
meibomian gland obstructions, being able to treat within the duct
itself will have advantages by avoiding thermal injury to eyelid
tissue surfaces, which are in close proximity to the ducts, and the
eye, cornea, and other unintended structures that are clearly
thermally sensitive tissues.
[0118] FIG. 5 is a flowchart illustrating an exemplary process of
directing RF energy to the eyelid relating to treating the
meibomian glands. In this regard, in one embodiment, RF energy is
applied via the RF electrode 32 through a surface of the eyelid to
melt, soften, or loosen obstructions in the meibomian glands to
treat MGD in basic form, as shown in the flowchart of FIG. 5. In
FIG. 5, RF energy is transmitted from a RF source (see, e.g., RF
generator 64, FIG. 10) to the RF electrode 32 and applied through a
surface of the eyelid 28 to melt, loosen, or soften obstructions or
occlusions in the meibomian glands 30 (step 36). For example, in
one embodiment, the RF energy may be applied to raise the
temperature of the tissue within the meibomian glands 30, as well
as any obstructions within the meibomian glands 30 to 43-47 degrees
Celsius. In other embodiment, the temperature range may vary. A
time range to direct RF energy may be a period between 1-10
minutes, and may be limited to a range of 3-6 minutes. The RF
energy may be regulated, meaning that a RF controller means or
element (see, e.g., controller 68 in FIG. 11) is used to control
the application of RF energy such that the temperatures and means
of application are safe for the structures of the eye, including
but not limited to the inner surface of the eyelid, and a
sufficient temperature is reached for melting, loosening, or
softening an occlusion or obstruction in the meibomian gland. By
sufficient temperature, this refers to the amount of RF energy
needed to heat the palpebral conjunctiva to achieve the desired
melting, loosening, or softening of the obstruction.
[0119] Still referring to FIG. 5, the application of the RF energy
may be maintained for a period of time until the temperature
reaches the desired level sufficient to melt, loosen, or soften the
obstructions or occlusions (step 38). For example, the heat may be
applied for 1 to 10 minutes in one embodiment. In other
embodiments, various amounts of time for the RF energy application
may be used. Thereafter, either during the application of the RF
energy or after, obstructions or occlusions in the meibomian glands
may be expressed so that sebum flow is restored from the glands to
establish a sufficient lipid layer (step 40).
[0120] In one embodiment, the ability to effectively and more
efficiently raise the temperature at the meibomian glands may prove
instrumental in melting, loosening, or softening obstructions or
occlusions in the meibomian gland to reach the loosening or melting
point of the obstruction or occlusion.
[0121] As used herein, the terms "melt," "loosen," and "soften" and
variants thereof are to be interpreted broadly. These terms broadly
encompass any change in form or state of the obstructive or
occluding material causing or contributing to an obstruction or
occlusion related to a disorder of the eye or eyelid structure to a
form such that the obstruction or occlusion can be more easily
freed or expressed. This includes, but is not limited to, changing
form from less of a solid form or state to more of a liquefied form
or state, including but not limited to dissolving, loosening,
liquefying, and/or softening of the obstructive or occluding
material to be removed, and/or dissolving, loosening, liquefying,
or softening of material that holds together particulate matters
causing or contributing towards the obstruction or occlusion
related to a disorder of the eye or eyelid structure and other
modalities.
[0122] Referring back to FIG. 5, optionally, after expression of
the occlusions or obstructions is performed (step 40), an optional
pharmacological agent may be applied to the meibomian gland to
promote the free flow of sebum and/or reduce or prevent
inflammation or infections of the eye or eyelids (step 42). Many
pharmacological agents have been proposed for treatment of dry eye
syndrome, any of which may be effective or more effective upon
clearing of obstructions within the meibomian glands. Some of the
pharmacological agents that may be utilized include, but are not
limited to: antibiotics such as topical or oral tetracycline and
chemically modified tetracycline, testosterone, topical or oral
corticosteroids, topical androgens or androgen analogues, omega 3
fatty acid compounds such as fish oils, Laennec, enzymes that
promote lipid production, agents that stimulate production of
enzymes that promote lipid production, and/or any agent which acts
as a secretagogue to enhance meibomian gland secretion or secretion
of other tear components. For example, androgen and androgen
analogues and TGF-beta have been reported to act as a secretagogue
to enhance meibomian gland secretion. These compounds are
illustrative examples of appropriate pharmacological agents, but
those skilled in the art will appreciate that other pharmacological
compounds may be utilized.
[0123] Treatment to remove the obstruction may involve the
application of an external regulated force to the eyelid and/or
directly over the obstructed orifice to loosen the obstruction
within the meibomian gland 10 and the orifice 16 of FIGS. 2 and 3.
The means for applying the force may be selected from one or more
of a number of modalities. In many of the embodiments disclosed
herein, RF energy is discussed. However, the means for applying the
force may be selected from one or more of any number of modalities
wherein the frequency of vibration may be including low frequency
vibration (generally less than 1000 Hz), sonic (generally 1000 Hz
to 20,000 Hz) or ultrasonic energy (generally greater than 20,000
Hz), fluid jet such as air or water, microwave energy, needles,
laser energy, aspiration/suction, vacuum, pressure, compression,
and functional equivalents thereof, in lieu of or in addition to RF
energy. In addition, once a modality is chosen, the physician will
have to determine the optimum treatment parameters so that each of
the foregoing modalities will be applied to the eyelid such that
the force (or energy, as appropriate) provided thereby is
transmitted through the eyelid tissue to the obstruction. Further,
the treatment intensity and length of application of these external
forces will vary with the size and composition of the obstruction.
Once a treatment protocol is established, the force can either be
set per variable within a preselected range. Experiments were
performed using an eccentric vibrating motor applied directly to
the human eyelids. Bench tests of the vibration revealed the
following data points, specifically setting number 3 was shown to
be clinically effective to loosen the obstruction within the
meibomian gland and orifice:
TABLE-US-00001 Vibration Freq. Vibration Amplitude Setting (Hz.)
(in/.mu.m) 1 51 .001 in. (25.4 .mu.m) 2 118 .004 in. (100 .mu.m) 3
165.5 .0062 in. (157.5 .mu.m)
[0124] Once the obstruction has been loosened from the walls of the
meibomian gland 10, it may be operated upon such that it will pass
through the orifice 16 in a manner which causes little or no pain
or discomfort to the patent. This can be accomplished by heating to
soften or liquefy the obstruction 22 or 24 up to a range of thirty
seven degrees centigrade (37.degree. C.) to fifty degrees
centigrade (50.degree. C.) with the preferred operating range being
forty degrees centigrade (40.degree. C.) to forty seven degrees
centigrade (47.degree. C.) and desired modality of forty two
degrees centigrade (42.degree. C.) to forty six degrees centigrade
(46.degree. C.) so that it easily passes through the orifice (or
with minimal non-painful expansion thereof). In one embodiment, the
heating to soften or liquefy the obstructions 22 or 24 in the
meibomian glands is done by RF heating, with the RF electrode 32 as
shown in FIG. 4 being one non-limiting example. However, other
modalities for heating are possible and may include conduction,
convection and radiation supplied by one or more of the following:
thermal conduction, thermal convection, ultrasonic energy, laser
energy, direct and/or indirect transfer from heat source and
microwave energy which may be applied for a preselected period of
time. By varying the amplitude, intensity and length of
application, some of the foregoing modalities may also be employed
to fracture or break up the obstruction. It will be noted that a
closed loop feedback control system, well known to those skilled in
the art may be employed during heating to measure temperature
proximate the eyelid to ensure that the obstruction does, in fact,
reach a temperature sufficient to turn the obstructive material
into a flowable, liquid or semi-liquid state.
[0125] Extraction of the softened, broken apart or fractured
obstruction may be accomplished by one or more of the following:
needles, micro-needles, aspiration/suction, vacuum, pressure and
compression. One embodiment includes a suction system that is
placed over the gland orifice may be employed to suck out the
components of the softened, loosened or liquefied obstruction or
the pieces thereof, as appropriate or alternatively, to employ
suction to collect the obstruction as it exits the gland orifice.
In order to be clinically effective, the foregoing modalities for
extracting or expressing the obstruction should be administered in
a fashion that is regulated, i.e., done in a repeatable manner.
[0126] In addition to the apparatus described above in FIG. 4 that
includes an RF electrode 32 positioned proximate to an outer
surface of the eyelid 28 and configured to direct RF energy in a
direction into the eyelid, other apparatuses may be used to aid in
the extraction or expression of obstructions in the meibomian
glands. One embodiment of an apparatus for unplugging the
obstructed gland channel 18 of FIG. 3 is schematically illustrated
in FIG. 6A. The apparatus comprises an RF source 44 which may be
direct current (battery powered) or alternating current (wall
socket) as desired. The RF source 44 is connected to a controller,
generally indicated at 46, which includes a power on/power off
switch 48. The controller 46 includes an RF means 50 for applying
an external force to the gland to loosen the obstruction. The RF
means 50 in this embodiment includes a probe 52, which is adapted
to vibrate at a preselected frequency at preselected amplitude. The
probe 52 may vibrate at sonic or ultrasonic frequencies as needed.
In addition, means for varying the frequency 54 and amplitude 56 of
the probe output, well known to those skilled in the art, are
provided. The RF means 50 may be used for applying the regulated
external force or regulated energy to the obstruction. Although the
embodiment shown in FIG. 4 illustrates an RF source 44 and an RF
means 40, other types of power sources and means for applying a
force may be used, including but not limited to a fluid jet, air
fluid, water fluid, microwave energy, needles, micro-needles, laser
energy, RF energy, aspiration, suction, vacuum, pressure,
piezoelectric, and compression.
[0127] Turning now to FIG. 6B, a small ultrasonic probe 52 (and
specifically the probe tip) is illustrated in FIG. 7C in place on
the eyelid. The probe 52 is adapted to deliver RF energy through
the skin into the obstruction 22 or 24 (as shown in FIG. 3) in
order to loosen, liquefy, and/or fracture the obstruction. In one
embodiment, as seen in FIGS. 6B and 7B, the probe 52 may contain an
RF element 53 for directing RF energy though an eyelid to
selectively target an obstruction in the meibomian gland in order
to soften, melt, or liquefy the obstruction. The RF element may be
similar to the RF electrode shown in FIG. 4 in one embodiment. More
specifically, by tuning the probe output so that the obstruction 22
or 24 resonates (by adjusting the frequency and amplitude of the
signal) energy is efficiently transferred to the obstruction and
sympathetic vibration of the obstruction 22 or 24 occurs with
minimal energy transfer to the surrounding tissues. In some
instances, vibration alone may be sufficient to change the
characteristics of the obstruction 22 or 24 such that vigorous
blinking may express the obstruction remnants.
[0128] In addition to vibration alternative force, energy,
aspiration and/or chemical/pharmacological agents can be used to
open up the channel 18. The probe may be further equipped with
aspiration means 57 (best illustrated in FIG. 7C) for introducing
aspiration, suction or vacuum into the gland channel 18 to evacuate
the obstruction remnants. Alternatively, heat and aspiration may be
employed in lieu of or in addition vibration.
[0129] In another embodiment, the probe 52 may be equipped with a
RF heating element 59, which may be regulated to provide relatively
precise amounts of energy in the previously mentioned ranges that
assists in softening, liquefying or melting the obstruction 22 or
24 via heat transfer through the tissue when the probe is placed
against the tissue. In a further embodiment, the probe 52 may use
the RF element 53 to deliver vibrational and/or thermal energy to
the obstruction 22 or 24 without contacting the gland.
[0130] In other embodiments, a solid state heating element may be
used in place of or in addition to the RF heating element 59.
Further, in other embodiments, other potential energy sources may
be used, such as laser light supplied by titanium, argon, krypton
or microwave energy.
[0131] After the obstruction is softened, melted, loosened,
liquefied, and/or fractured, extraction of the obstruction would be
accomplished by any of the means described herein.
[0132] In one embodiment, pressure may be applied to the tissue as
shown in FIGS. 8A, 8B, and 9 by rollers (or drums) 60 or 62 which
are placed in front of and/or behind the meibomian gland with the
rollers applying constant regulated pressure to the meibomian
glands to apply a "milking" type force to expel the obstruction to
return the gland to normal secretion levels. The rollers can be
connected to heat, aspiration, vacuum, and/or suction that operate
as described herein.
[0133] In operation, the physician would place the rollers 62 in
contact with the eyelid, either inside, outside or both. Lateral
movement of the rollers 62 would cause pressure to be applied to
the gland to remove the obstruction. Alternatively, aspiration,
suction and/or vacuum could be applied to extract the obstruction
and material from the vicinity of the gland opening. In addition,
depending upon the obstruction, aspiration, suction and/or vacuum
alone may be sufficient to extract the obstruction.
[0134] Additional features may also be provided to the rollers 62
such as a regulated RF heating element (not shown) which could be
placed in the outer covering near the tip as shown in FIGS. 6A-7C.
In addition, the roller 62 could be equipped such that ultrasonic
energy could be delivered to the obstruction as discussed herein
above.
[0135] The RF energy used to soften the obstructions in the
meibomian glands may be generated by a RF source, or generator 64,
as shown in FIG. 10. FIG. 10 illustrates an exemplary system for
directing RF energy from a RF generator 64 to an RF electrode 32
positioned proximate an eyelid 28. In one embodiment, the RF
generator 64 may be an electrical surgical unit (ESU). The RF
generator 64 may be directly connected to the RF electrode 32 via a
connection 66, which may be an electrical wire in one embodiment.
The RF generator 64 can be controlled by a physician or other
trained professional via a footswitch, hand button, or finger
button actuation.
[0136] FIG. 11 illustrates a controller 68 to be used with the
system of FIG. 10 for facilitating selective and controllable
communication of RF energy and/or force to the eyelid, according to
one embodiment. The controller 68 may include a RF control system
70 and a force control system 72. The force control system 72 is
the control component within the controller 68 that controls the
force applied to the patient's eye. The RF control system 70 is the
control component within the controller 68 that controls the RF
energy applied to the patient's eye. The force control system 72
also communicates the pressure in tubing 74 to a force sensor 76
within the force control system 72. The force sensor 76 is used to
determine a pressure level in the tubing 174 as well as to provide
feedback to the controller 68 to provide the various functions and
controls for the system, as will be described in more detail below.
The force sensor 76 also allows the recordation of pressure data to
be recorded by the controller 68, or an external data acquisition
device (not shown) coupled to the controller 68, if desired.
[0137] The application of RF energy may be regulated, meaning that
a RF controller means or element is controlled to be within the
temperatures and means that are safe for the structures of the eye,
including the inner surface of the eyelid, and at a sufficient
temperature for melting, loosening, or softening an occlusion or
obstruction in the meibomian gland. The RF energy is maintained for
a period of time sufficient to melt, loosen, or soften the
occlusions or obstructions. Either during the application of the RF
energy or after the application of RF energy has been discontinued,
the occlusions or obstructions in the meibomian glands are
expressed to remove obstructions or occlusions thus providing an
improved pathway to restore or improve sebum flow from the
gland.
[0138] In one embodiment, increasing the temperature of the surface
of the palpebral conjunctiva to at least 37 degrees Celsius can
begin to provide therapeutic effect for milder cases of MGD. A
therapeutic temperature can be any temperature above body
temperature. One preferred range for treatment is 43 to 45 degrees
Celsius, with a target of 43 to 44.5 degrees Celsius. Temperature
in this range has been found effective and comfortable to the
patient when treating MGD. A time range to direct the RF energy may
be a period between 1-10 minutes, and may be limited to a range of
3-6 minutes.
[0139] In one embodiment, the application of RF energy may be
regulated. Regulated RF energy can include controlling the
application of RF energy according to a temperature profile. The
temperature profile may be a constant temperature, including
ramp-ups, ramp-downs, peaks and valleys. Further, the temperature
profile may include heat pulses or be modulated with various
characteristics, including the use of on/off switching or pulse
width modulation (PWM) techniques for example. The use of modulated
RF energy may allow the temperature to be raised even higher at the
eyelid without damages to the patient's eyelid since the increased
temperatures are applied for shorter periods of time. Obstructions
or occlusions in the meibomian glands may have melting, loosening,
or softening points that are beyond temperatures that may be
applied without the use of modulated RF energy. The temperature
needed to melt, loosen, or soften obstructions or occlusions may
depend on how keratinized the obstruction or occlusion is. Not all
obstructions or occlusions have the same melting, loosening, or
softening points.
[0140] By example only, elevated temperatures between 45 and 55
degrees Celsius may be possible when directing regulated RF energy,
especially if the eyelid has been anesthetized. However, the RF
energy must always be applied to the eyelid at temperatures that
take into consideration the pain response of the patient as well as
whether damage will occur to the patient's eyelid and/or
surrounding tissues. Depending on the severity of the patient's MGD
or the patient's pain tolerance, elevated temperatures may be used
with patient's on an individualized basis when directing RF energy.
It has been found that lighter skinned patients can generally
tolerate less heat than darker skinned patients, and darker skinned
patients tend to exhibit less inflammation as a result of exposure
to the heat. Other factors, including humidity, may contribute to a
patient's tolerate to greater temperatures. For example, humans can
generally tolerate temperatures up to 70 to 80 degrees Celsius in
dry saunas where humidity is low. Application of RF energy in
higher humidity environments may cause pain and/or burns to occur
at lower temperatures.
[0141] Severe cases of MGD that cause substantial irritation or
risk to the patient may even call for temperatures that would
produce category one or two burns to the patient's eyelid, since
these burns generally heal. Temperatures that cause category three
burns should be avoided. In summary, treatment times and/or
temperature can be adjusted to account for these differences.
Embodiments disclosed herein are not limited to any particular
temperature or time ranges as long as therapeutic temperature is
being applied.
[0142] The regulated RF energy can be maintained at a therapeutic
temperature for a treatment period. The treatment period can be
approximately 1 to 10 minutes for example. The RF energy could also
be repeatedly applied and maintained for a desired period of time
to keep the occlusion or obstruction in a melted, loosened, or
softened state. Either during or after such treatment by regulated
RF energy, mechanical expression of lipids and other fluids from
the meibomian glands has been found to clear obstructions which
have essentially melted or been placed in a suspension state (by
virtue of melting materials binding solids together).
[0143] Also, agents, such as Restasis (cyclosporine A), that
replace or promote production of the tear component may also be
applied more effectively after treating the meibomian glands
according to the embodiments disclosed herein. Treating the
meibomian glands improves the lipid layer, thus reducing
evaporation and conserving the aqueous layer. Conservation of the
aqueous layer reduces the need for tear substitutes to be applied
through tear component agents. Thus, tear component agents may not
have to be used as often when employing the embodiments disclosed
herein to treat a patient's MGD.
[0144] In another embodiment, a method and apparatus for treating
meibomian gland disease (MGD) using RF/microwave energy for rapid
heating and removal of MGD obstructions is disclosed. In this
embodiment, an RF electrode may be part of an eyecup apparatus, as
shown in FIGS. 12A-14. It is the objective of this method and
apparatus for treating MGD to reduce procedural times and decrease
patient discomfort. It is a further objective to allow patients on
a cosmetic basis to return to normal activities without a need for
a recovery time from pain, discomfort, pigmentation at the eye lid,
or aesthetic discoloration (redness) visible post-treatment. It is
a further objective of the described eyecup mechanism to provide
for the application of therapeutic drugs or topical pharmacological
agents directly at the site of the meibomian gland openings
immediately post treatment all within the same device and in the
same procedural setting.
[0145] FIG. 12A is a broken side view of an exemplary eyecup
comprising an exemplary RF electrode configured to direct RF energy
to the internal portions of meibomian glands according to one
embodiment. In one embodiment, heating the meibomian glands, as
well as any obstructions within the meibomian glands, from the
outside of an eyelid 28 is accomplished by the use of RF or
microwave energy. The energy source is directed to focus below the
skin layer and through the tarsal plate into an area 78 of an
eyelid 28 where meibomian glands are located.
[0146] Looking at FIG. 12A, an eyecup 80 may be provided and
positioned on the surface of the eye 26 behind the inner surface of
the eyelid 28. The eyecup 80 is configured to overlie the outer
surface of the eyelid 28 and substantially conform to the surface
shape thereof. Extending perpendicularly outward from the body of
the eyecup 80 is a pair of flexible spaced apart opposing
cantilevered engagement arms 83 which include integrally molded
finger grips or handles 85 as part of handle 87. An RF delivery
means may be provided as a RF electrode 32. A connection 82, as
seen in FIG. 12A, is configured to be connected to an RF generator,
such as RF generator 64 in FIG. 10, to allow RF energy to be
generated at RF electrode 32. The eyecup 80 further includes a
cooling mechanism 84. As described above, the application of the RF
energy below the skin layer and into the tarsal plate can also be
achieved with combination with a skin cooling mechanism, such as
cooling mechanism 84. In one embodiment, the surface of the RF
electrode 32 does not heat the skin layer directly. The RF
electrode 32 or other RF energy delivery means can be located above
the skin layer by use of a spacer or insulator. By use of an
insulator, the skin layer is not heated directly.
[0147] In one embodiment, the cooling mechanism 84 may be a cooling
membrane. By use of a cooling membrane, as shown in FIGS. 12A-13,
the skin layer stays unheated while the gland duct materials are
being heated. In one embodiment, the cooling membrane is a bladder
that has continuous flowing coolant media to maintain low skin
layer temperatures. In one embodiment, the coolant could be
cryogenic media. In addition, the coolant could be a reduced
temperature or iced saline solution. In one embodiment, the cooling
membrane is a vessel with an internal air vacuum to act as an
insulator. In another embodiment, the cooling membrane is a conduit
with flowing air running through it to reduce surface temperature
heating.
[0148] In one embodiment, RF/microwave energy can be modified by
altering the wave length, wave form, power, frequency, pulse
duration or continuous waveforms, and shape of the energy
delivering means.
[0149] The above modifications are directed towards preferentially
heating the gland duct materials as seen in FIG. 12B. A zone of
preferential heating 86 and a zone of preferential cooling 84 may
be created. The RF energy generated by the RF electrode 32 may be
targeted in the zone of preferential heating 86, where the
meibomian glands 30 are located. Gland duct materials will have
different electrical and thermal conductivity properties than their
surrounding tissues. There can be significant differences in
dielectric properties between the duct materials and the
surrounding gland and eye lid tissues themselves. Historically in
other RF applications, these differences can be more pronounced at
lower frequencies and in some clinical applications, below 100 kHz.
The systems disclosed herein can efficiently direct RF energy to
tissues below the skin layer without substantially heating the skin
layer itself. Other systems that describe heating below the skin
layer without a separate mechanism for cooling the skin can be
found in (WO/2006/077567), entitled "Improved System and Method for
Heating Biological Tissue Via RF Energy" or U.S. Pat. No.
5,948,011, entitled "Method for controlled contraction of collagen
tissue via non-continuous energy delivery."
[0150] In one embodiment, as shown in FIGS. 12A-15, a specially
designed eyecup (described below) prevents thermal energy from
being delivered to the globe and sensitive structures of the eye.
The heating mechanism of the eyecup is nearly instantaneous due to
the mechanism of RF heating, conductivity of cellular components,
and preferential heating of lipid containing cellular components.
Dead cells, dried out cellular matter, or material clusters devoid
of water or fluid components would tend to be affected less by RF
energy than other cells.
[0151] By focusing the RF energy below the skin layer, a more
efficient thermal process being directed at the site of meibomian
glands could be achieved without damaging outer layer tissues in a
more rapid time frame. The meibomian glands 30 in particular are
located near the inside of the eyelid 28. As seen in FIG. 12A, a
temperature monitoring means 90 may be provided on the eyecup 80 in
order to maintain temperatures below 45 degrees Celsius (or any
temperature above body temperature below 54 degrees Celsius).
[0152] As described above, the application of the RF energy below
the skin layer and into the tarsal plate can also be achieved with
combination with a skin cooling mechanism. In one embodiment, the
surface of the energy delivering means does not heat the skin layer
directly. The RF electrode or other RF energy delivery means can be
located above the skin layer by use of a spacer. By use of an
insulator, the skin layer is not heated directly.
[0153] In addition, in one embodiment, the system may also include
a cooling membrane. By use of a cooling membrane, as shown in FIGS.
12A-13, the skin layer stays unheated while the gland duct
materials are being heated. In one embodiment, a conduit 92 may be
provided as part of the handle 87 or some other part of the eyecup
80 in order to provide cooling media to be introduced to the eye
area, as indicated by the arrows 94 in FIG. 13. In another
embodiment, the cooling membrane is a bladder that has continuous
flowing coolant media to maintain low skin layer temperatures. In
one embodiment, the coolant may be could be cryogenic media. In
addition, the coolant could be a reduced temperature or iced saline
solution. In one embodiment, the cooling membrane is a vessel with
an internal air vacuum to act as an insulator. In another
embodiment, the cooling membrane is a conduit (similar to conduit
92 in FIG. 13) with flowing air running through it to reduce
surface temperature heating. The surface of the RF electrode 32 or
RF energy delivering means and/or insulator may also apply
mechanical pressure (beyond stabilizing the energy delivery
mechanism) to express gland duct materials for greater patient
comfort and without marking the outer/visible eyelid.
[0154] In another embodiment, the RF electrode 32 or RF energy
means on the outside of the eyelid 28 preferentially heats a
conductive plate or plates 96 located on the periphery of the
eyecup 80, as seen in FIG. 14. As the conductive plate(s) 96 are
heated to controlled temperatures, the adjacent inner eyelid 28 is
heated by thermal conductivity, as shown in FIG. 14. In particular,
the zone 86 where the meibomian glands 30 are located is
preferentially heated as compared to the other tissues of the
eyelid 28.
[0155] In one embodiment, as shown in FIG. 15, an RF electrode 32
(or microwave antenna) is placed on an outer surface of the eyelid
28 to direct RF/microwave energy rapidly to an internal portion of
meibomian glands 30 within the eyelid 28. The RF energy is applied
to selectively target gland duct contents, including any
obstructions that may be within the channel or duct of the
meibomian gland. The RF energy is applied completely through the
eyelid 28, but does not heat the outer surface of the eyelid 28. In
addition, the microwave/RF energy in this instance equally would
not be directed on the inner surface of the eyelid 28 or the
orifices 16 of the meibomian glands 30. Instead, only the internal
duct or channel 18 of the meibomian glands 30 is heated by the
application of the RF energy in this embodiment.
[0156] FIG. 15 is a broken side view of an exemplary eyecup
comprising an exemplary RF electrode positioned on an outer surface
of an eyelid. An eyecup 80 is positioned as described above. An RF
electrode 32 is positioned proximate the outer surface of eyelid
28, The eyecup 80 also comprises a support structure 98 and an
expression means 100, which may be used as a backplate to apply
pressure to express melted or softened obstructions from the
meibomian glands.
[0157] One advantage of the single electrode, outer eyelid system
illustrated in FIG. 15 is that the RF electrode 32 directs RF
energy within the eyelid tissue at a predetermined depth while
structurally the electronics of the system resides on the exterior
of the eyelid 28, thereby decreasing the amount of materials
required to fit underneath the eyelid 28 during treatment, as seen
in FIG. 15. The triangles 102 show where the RF energy is being
directed and the thermal gradient created thereby.
[0158] Another advantage of having the RF electrode 32 on the
exterior of the eyelid 28 is that the RF electrode 32 will not be
in the location where expressed materials accumulate. Expressed
fluids from the inner eyelid 28 will not be obstructed by the
physical presence of the RF electrode 32 and its electronics and
the fluid collection process will occur unimpeded. In addition, an
RF electrode 32 on the exterior location will not be affected in
performance by the volume or mass of expressed materials from the
glands. In general for this embodiment, the RF electrode 32 will
not interfere with any aspiration or collection mechanism for the
expressed materials and vice versa.
[0159] Microwave and RF energy may be utilized to pinpoint thermal
energy at specific target tissues. In addition, RF and microwave
energy can be manipulated to be absorbed or directed for a certain
type of cellular content or tissue material make up. For instance,
the RF or microwave energy waveforms can be directed to be absorbed
preferentially by energy absorbing cellular fluids, saline or lipid
containing materials found in the ducts, channels, or acini of the
meibomian glands rather than the cellular structures of the
meibomian glands themselves. Pulsed waveform energy may react more
preferentially on certain cellular fluids and contents than
continuous waveforms. Specifically for the removal of meibomian
gland obstructions, the desired temperature range for liquefying
lipid containing obstructions is quickly and easily achievable
using RF energy. Thus, in the area of removing meibomian gland
obstructions, a series of short pulsed RF energy waves or
microwaves could preferentially heat gland contents within the
eyelid without raising the temperature of surrounding tissues or
unintended tissue surfaces significantly.
[0160] Besides selectively heating different types of tissue
contents and not heating indiscriminately surrounding tissue,
microwave/RF energy can be directed to perform at a predetermined
depth as seen in hyperthermia treatments or when treating a
specific depth within the wall of the arterial vessel. For
meibomian gland obstructions, being able to treat within the duct
itself will have advantages by avoiding thermal injury to eyelid
tissue surfaces, which are in close proximity to the ducts, and the
eye, cornea, and other unintended structures that are clearly
thermally sensitive tissues.
[0161] Another important benefit with the described systems is that
microwave/RF energy can provide a very rapid direct internal
heating source. The clear advantage with this would be an overall
decrease in procedural time and reducing patient discomfort from
the procedure. In addition since the thermal energy does not
require conductive heating or a thermal gradient through tissue to
reach its intended target, theoretically terminating the procedure
could occur more quickly. Finally, for busy physician practices,
shorter procedural times will improve patient flow through the
practice.
[0162] In FIG. 15, the desired amount of thermal energy to deliver
to contents within the meibomian glands is an amount sufficient to
heat the contents to between 37 and 45 degrees C. The RF energy or
microwave energy can be controlled by a controller, such as
controller 68 in FIG. 11, or by the RF generator 64 in FIG. 10, to
selectively heat the contents of the ducts and channel of the
meibomian glands to a known temperature within the tissues and/or
to selectively heat lipid containing materials. This may be done by
adjusting the power and duration of the applied RF energy, or by
changing the waveform shape (stepped or curved). The waveforms may
be pulsed or continuous waveforms. In another embodiment, the shape
of the RF electrode or microwave antenna that delivers or emits the
RF or microwave energy may be changed to selectively heat the
contents of the ducts and channel of the meibomian glands to a
known temperature within the tissues and/or to selectively heat
lipid containing materials. In this manner, the RF energy will be
applied to selectively target any obstructions within the duct,
channel, or acini of the meibomian glands to melt, soften, or
loosen such obstructions. Once melted, softened, or loosened, the
obstructions may be more easily expressed from within the channel
of the meibomian gland through an orifice of the meibomian
gland.
[0163] In another embodiment, the RF electrode 32 may be placed on
an inner surface of the eyelid 28. This provides certain advantages
over the RF electrode 32 being positioned on the outer surface of
the eyelid 28, including but not limited to the ability to
effectively and more efficiently raise the temperature at the
meibomian glands, which may prove instrumental in melting,
loosening, or softening obstructions or occlusions in the meibomian
gland to reach the loosening or melting point of the obstruction or
occlusion.
[0164] FIG. 16 illustrates an exemplary eyelid temperature profile
104 of an inner and outer eyelid temperature versus time when RF
energy is applied to the exterior of the eyelid. FIG. 17
illustrates an exemplary eyelid lid temperature profile 106 of
inside and outside eyelid temperature versus time when heat is
applied to the inside the eyelid.
[0165] An exemplary lid temperature profile 106 that may be
generated when RF energy is applied to the inside of the eyelid is
illustrated in FIG. 17. There, a graph depicts what the temperature
of the inner surface of an eyelid may be as a function of time when
a source of RF energy is applied to an example subject patient. A
RF electrode attached to the inside of the patient's eyelid is
turned on for a period of time. For this patient, it took
approximately 30 seconds for the eyelid's inner surface to reach
about 44 degrees Celsius. Unlike the lid temperature profile 104
illustrated in FIG. 16, the inner surface of the patient's eyelid
did reach a higher temperature when RF energy was applied to the
inside of the eyelid. For example, it may only take two to three
minutes to bring the temperature at the meibomian glands to 43-45
degrees Celsius or higher when directing RF energy to the inside of
the eyelid. In one embodiment, the ability to raise the temperature
at the meibomian glands may prove instrumental in melting,
loosening, or softening obstructions or occlusions in the meibomian
gland to reach the loosening, softening, or melting point of the
obstruction or occlusion.
[0166] In this regard, an embodiment to direct RF energy to the
inside or inner surface of the eyelid proximate the meibomian
glands to treat MGD in basic form is illustrated in the flowchart
of FIG. 18. This has the advantage in that it typically takes less
time to raise the temperature at the meibomian glands sufficient to
melt, loosen, or soften an obstruction or occlusion than if heat
were applied directly to the outside of the eyelid. Further,
directing RF energy to the inside of the eyelid may allow higher
temperatures to be achieved than if the outside of the eyelid were
heated.
[0167] First, RF energy is applied to the inner surface of the
eyelid to a temperature adequate to melt, loosen, or soften
obstructions or occlusions in the meibomian glands (step 108). For
example, RF energy may be applied to raise the temperature at the
inside of the eyelid to 43-47 degrees Celsius in one embodiment,
although different temperature ranges may be achieved in other
embodiments. A time range to direct the RF energy may be a period
between 1-10 minutes, and may be limited to a range of 3-6 minutes
in one embodiment. The RF energy may be regulated meaning that a RF
control means or element is controlled to be within the
temperatures and means that are safe for the inner surface of the
eyelid and at a sufficient temperature for melting, loosening, or
softening an occlusion or obstruction in the meibomian gland. By
sufficient temperature, this refers to the amount of heating needed
to heat the palpebral conjunctiva to achieve the desired melting,
loosening, or softening of the obstruction. The RF energy may be
maintained for a period of time until the temperature reaches the
desired level sufficient to melt, loosen, or soften the
obstructions or occlusions (step 110). For example, the RF energy
may be applied for 1 to 10 minutes in one embodiment, although
other embodiments may use different amounts of application time for
the RF energy. Thereafter, either during the application of the RF
energy or after, obstructions or occlusions in the meibomian glands
may be expressed so that sebum flow is restored from the glands to
establish a sufficient lipid layer (step 112).
[0168] In this manner, in one embodiment, the ability to
effectively and more efficiently raise the temperature at the
meibomian glands may prove instrumental in melting, loosening, or
softening obstructions or occlusions in the meibomian gland to
reach the loosening or melting point of the obstruction or
occlusion.
[0169] As used herein, the terms "melt," "loosen," and "soften" and
variants thereof are to be interpreted broadly. These terms broadly
encompass any change in form or state of the obstructive or
occluding material causing or contributing to an obstruction or
occlusion related to a disorder of the eye or eyelid structure to a
form such that the obstruction or occlusion can be more easily
freed or expressed. This includes, but is not limited to, changing
form from less of a solid form or state to more of a liquefied form
or state, including but not limited to dissolving, loosening,
liquefying, and/or softening of the obstructive or occluding
material to be removed, and/or dissolving, loosening, liquefying,
or softening of material that holds together particulate matters
causing or contributing towards the obstruction or occlusion
related to a disorder of the eye or eyelid structure and other
modalities.
[0170] The application of RF energy may be regulated, meaning that
a RF control means or element is controlled to be within the
temperatures and means that are safe for the inner surface of the
eyelid and at a sufficient temperature for melting, loosening, or
softening an occlusion or obstruction in the meibomian gland. The
RF energy is maintained for a period of time sufficient to melt,
loosen, or soften the occlusions or obstructions. Either during the
RF energy application or after the application of RF energy is
stopped, the occlusions or obstructions in the meibomian glands are
expressed to remove obstructions or occlusions thus providing an
improved pathway to restore or improve sebum flow from the
gland.
[0171] In one embodiment, increasing the temperature of the surface
of the palpebral conjunctiva to at least 37 degrees Celsius can
begin to provide therapeutic effect for milder cases of MGD. A
therapeutic temperature can be any temperature above body
temperature. One preferred range for treatment is 43 to 45 degrees
Celsius, with a target of 43 to 44.5 degrees Celsius. A time range
to direct RF energy may be a period between 1-10 minutes, and may
be limited to a range of 3-6 minutes. Temperature in this range has
been found effective and comfortable to the patient when treating
MGD.
[0172] In one embodiment, the application of RF energy may be
regulated. Regulated RF energy can include controlling RF energy
according to a temperature profile. The temperature profile may be
a constant temperature, include ramp-ups, ramp-downs, peaks and
valleys. Further, the temperature profile may include RF energy
pulses or be modulated with various characteristics, including the
use of on/off switching or pulse width modulation (PWM) techniques
for example. The use of modulated RF energy may allow the
temperature to be raised even higher at the eyelid without damages
to the patient's eyelid since the increased temperatures are
applied for shorter periods of time. Obstructions or occlusions in
the meibomian glands may have melting, loosening, or softening
points that are beyond temperatures that may be applied without the
use of modulated heat. The temperature needed to melt, loosen, or
soften obstructions or occlusions may depend on how keratinized the
obstruction or occlusion is. Not all obstructions or occlusions
have the same melting, loosening, or softening points.
[0173] By example only, elevated temperatures between 45 and 55
degrees Celsius may be possible when directing regulated RF energy,
especially if the eyelid has been anesthetized. However, RF energy
must always be applied to the eyelid at temperatures that take into
consideration the pain response of the patient as well as whether
damage will occur to the patient's eyelid and/or surrounding
tissues. Depending on the severity of the patient's MGD or the
patient's pain tolerance, elevated temperatures may be used with
patient's on an individualized basis when directing RF energy. It
has been found that lighter skinned patients can generally tolerate
less high temperatures than darker skinned patients, and darker
skinned patients tend to exhibit less inflammation as a result of
exposure to the higher temperatures. Other factors, including
humidity, may contribute to a patient's tolerate to greater
temperatures. For example, humans can generally tolerate
temperatures up to 70 to 80 degrees Celsius in dry saunas where
humidity is low. Application of RF energy in higher humidity
environments may cause pain and/or burns to occur at lower
temperatures.
[0174] Severe cases of MGD that cause substantial irritation or
risk to the patient may even call for temperatures that would
produce category one or two burns to the patient's eyelid, since
these burns generally heal. Temperatures that cause category three
burns should be avoided. In summary, treatment times and/or
temperature can be adjusted to account for these differences. The
embodiments described herein are not limited to any particular
temperature or time ranges as long as therapeutic temperature is
being applied.
[0175] The regulated RF energy can be maintained at a therapeutic
temperature for a treatment period. The treatment period can be
approximately 1 to 10 minutes for example. The RF energy could also
be repeatedly applied and maintained for a desired period of time
to keep the occlusion or obstruction in a melted, loosened, or
softened state. Either during or after such treatment by regulated
RF energy, mechanical expression of lipids and other fluids from
the meibomian glands has been found to clear obstructions which
have essentially melted or been placed in a suspension state (by
virtue of melting materials binding solids together).
[0176] Optionally, after expression of the occlusions or
obstructions is performed (step 112), an optional pharmacological
agent may be applied to the meibomian gland to promote the free
flow of sebum and/or reduce or prevent inflammation or infections
of the eye or eyelids (step 114). Many pharmacological agents have
been proposed for treatment of dry eye syndrome, any of which may
be effective or more effective upon clearing of obstructions within
the meibomian glands. Some of the pharmacological agents that may
be utilized include, but are not limited to: antibiotics such as
topical or oral tetracycline and chemically modified tetracycline,
testosterone, topical or oral corticosteroids, topical androgens or
androgen analogues, omega 3 fatty acid compounds such as fish oils,
Laennec, enzymes that promote lipid production, agents that
stimulate production of enzymes that promote lipid production,
and/or any agent which acts as a secretagogue to enhance meibomian
gland secretion or secretion of other tear components. For example,
androgen and androgen analogues and TGF-beta have been reported to
act as a secretagogue to enhance meibomian gland secretion. These
compounds are illustrative examples of appropriate pharmacological
agents, but those skilled in the art will appreciate that other
pharmacological compounds may be utilized.
[0177] Also, agents, such as Restasis (cyclosporine A), that
replace or promote production of the tear component may also be
applied more effectively after treating the meibomian glands
according to the embodiments disclosed herein. Treating the
meibomian glands improves the lipid layer, thus reducing
evaporation and conserving the aqueous layer. Conservation of the
aqueous layer reduces the need for tear substitutes to be applied
through tear component agents. Thus, tear component agents may not
have to be used as often when employing the embodiments disclosed
herein to treat a patient's MGD.
[0178] In the course of experimenting with the application of RF
energy to the inside of the eyelid, it was also discovered that
convective heat losses occur due to blood flow in the blood vessels
located inside the eyelid. Blood flow through blood vessels located
inside the eyelid produces convective heat losses. The blood flow
serves as a natural "heat sink" provided by the body. Convective
heat loss is lessened when directing RF energy to the inside of the
eyelid than when applying heat to the outside of the eyelid. This
is because fewer blood vessels are located between the meibomian
glands and the inside of the eyelid than the outside of the eyelid.
The meibomian glands are located closer to the inside of the
eyelid. However, convective heat loss still occurs when heating the
inside of the eyelid. However, if the blood flow were reduced,
convective heat losses could be minimized allowing for temperatures
to be attained and sustained at the meibomian glands in an even
more efficient manner and in less time.
[0179] In this regard, an exemplary lid temperature profile 116
when RF energy is applied to the inside of the eyelid and force at
various pressure levels is applied to the outside of the eyelid is
illustrated in FIG. 19. There, a graph depicts the temperature at
the inner and outer surface of an eyelid as a function of time when
a source of constant heat and pressure is applied to an example
subject patient. Initially, no heat or pressure is applied to the
eyelid. In this example, the temperature at the inside of the
eyelid is approximately 36 degrees Celsius while the temperature at
the outside of the eyelid is approximately 35 degrees Celsius. When
the RF energy source is turned on to direct RF energy to the inside
of the eyelid and a 70 mm Hg pressure is applied to the outside of
the eyelid, the temperature at the inside of the eyelid
dramatically increases quickly. The pressure being applied to the
eyelid is reducing blood flow in the eyelid, which reduces
convective heat loss and increases conductive heat gain. The
temperature at the outside of the eyelid increases quickly as well,
but less dramatically than at the inside of the eyelid since the RF
electrode is at the inside of the eyelid. A nominal temperature of
approximately 40.5 and 38.3 degrees Celsius is reached at the
inside and outside of the eyelid, respectively.
[0180] If the pressure is increased, even higher temperatures are
attained as illustrated in FIG. 19. Finally, when the RF energy
source is completely shut off, the temperature degrades. However,
the temperature at the eyelid does not degrade immediately due to
the force continuing to be applied. Again, the force reduces blood
flow to prevent convective heat loss. If both the RF energy source
and the force are shut off after being applied, the temperature at
the eyelid does degrade more rapidly. This is because blood flow in
the eyelid is unobstructed, allowing the body's blow flow to
quickly convect the heat away. Thus, the lid temperature profile
116 of FIG. 19 illustrates temperature at the eyelid can be
increased effectively and quickly with the application of force in
addition to the application of the RF energy Note that the
application of force to reduce convective heat loss can be applied
whether RF energy is applied via an RF electrode on the inside or
outside of the eyelid. As illustrated in FIG. 19, the application
of force is effective in both scenarios.
[0181] Thus, in one embodiment, the application of force to the
patient's eyelid in addition to RF energy is used. The application
of force can further assist in obtaining higher temperatures more
efficiently inside the eyelid at the palpebral conjunctiva and at
the meibomian gland in a shorter period of time and thus more
efficiently. This is because the application of force may reduce
blood flow to the eyelid to reduce convective heat loss, as
discussed above.
[0182] In this regard, an embodiment to direct RF energy and apply
force to the eyelid to treat MGD is illustrated in the flowchart of
FIG. 20. First, RF energy is applied to the eyelid to raise the
temperature at the meibomian glands to the desired level (step
118). For example, RF energy may be applied to raise the
temperature at the inside of the eyelid to 44-47 degrees Celsius.
The RF energy may be applied to the inside or outside of the
eyelid, or on both sides of the eyelid. The RF energy may also be
regulated, meaning that a RF control means or element is controlled
to be within the temperatures and means that are safe for the
eyelid and at a sufficient temperature for melting, loosening, or
softening an occlusion or obstruction in the meibomian gland. A
force is also applied to the eyelid to reduce blood flow in the
eyelid to allow the applied RF energy to more quickly raise the
temperature at the meibomian glands (step 120). The force may be
applied to the inside or outside of the eyelid.
[0183] The RF energy and/or force may be maintained for a period of
time sufficient to raise the temperature at the meibomian glands
sufficient to melt, loosen, or soften the obstructions or
occlusions (step 122). The force may be maintained after the
application of RF energy is stopped, or vice versa depending on the
treatment technique desired. Maintaining force after RF energy is
removed may cause the temperature at the meibomian glands to
dissipate more slowly than if force is removed. Maintaining RF
energy without maintaining force may be employed to allow blood
flow in the eyelids, such as between successive treatments. For
example, it may be desirable to maintain the RF energy to lessen
the total amount of treatment time while applying and removing
force between treatments. Also, it may not be necessary to apply
significant amounts of force or for the same duration as RF energy
if the obstruction or occlusion is located in close proximity to
the lid margin rather than in the deeper portions of the meibomian
gland.
[0184] Applying force can also result in a more efficient
conductive heat transfer from an applied RF electrode, because the
pressure created by the force causes the RF electrode to be
compressed against the tissue of the eyelid. This compression can
have several benefits. Compression spreads out the tissue to which
RF energy is applied thus making it thinner and improving
conductive heat transfer. Compression can also "squeeze out" air
pockets at the surface of the eyelid due to the microscopic
roughness of skin. Thus, compression of the RF electrode against
the eyelid increases the surface contact between the RF electrode
and the surface of the eyelid (which increases the heat transfer
equation) to provide a more effective conductive heat transfer to
the meibomian glands. This results in the meibomian glands being
heated to the desired temperature level in a shorter period of time
due to these gained efficiencies. Further, increased temperatures
may be attained that may not have otherwise been obtained, or
obtained using less heat or thermal energy. Because the RF
electrode is located in close proximity to the eyelid surface and
is further compressed against the eyelid surface, heat transfer is
very efficient providing for the temperature at the surface of the
eyelid to be very close to the temperature at the meibomian
glands.
[0185] Further, note that while the exact reduction in times to
heat the meibomian glands will vary from patient to patient when
force is applied, and may be based on the amount of pressure
applied to the patient's eyelid, in general, the change in heating
times can vary by as much as several hundred percent, for example,
when compared to previous methods. As an example, this can
translate into five (5) or more minutes that one has to expel an
obstruction or occlusion before such re-solidifies when compared
with prior methods.
[0186] The force may be regulated, meaning that a force generating
means is controlled to be within the pressure ranges that are safe
to be applied to the eyelid and at sufficient pressure to allow the
temperature at the meibomian gland to be raised sufficiently. The
force can also be a constant force and be provided manually. For
example, force may be provided by a technician or doctor's finger
or thumb as RF energy is applied. The force may be applied during
the application of RF energy, after the application of RF energy,
or both during and after the application of RF energy. In either
case, the force may assist in expressing occlusions or obstructions
when in a loosened, softened, or melted state from the meibomian
glands. The force may include vibratory type forces, including
those generated mechanically or those using fluid type devices or
mechanisms. The force can be applied at a particular location or
vector of the patient's eyelid to be specifically directed to the
meibomian glands. This may reduce the level of force needed to
express obstructions or occlusions in the glands. The level of
force needed to express obstructions or occlusions in the glands
may also be greatly reduced when RF energy is selectively applied
to the obstructions or occlusions to place them in a melted,
softened, or loosened state.
[0187] The application of force can also stimulate the movement of
fluids or suspensions of occlusions or obstructions from the
glands. Embodiments disclosed herein can be used with devices which
generally apply a regulated force or milking action to the eyelid
to express the fluids or suspensions or to otherwise mechanically
stimulate the movement of fluids from the glands. In some
instances, a small, gentle, continuous force applied to the eyelid
will assist in expression of the fluids and suspensions. Vibration
can also be used when applying force simultaneously or immediately
after the heating to further assist in the expression.
[0188] Thereafter, either during the application of RF energy
and/or the application of force or after either, obstructions or
occlusions in the meibomian glands may be expressed so that sebum
flow is restored from the glands to establish a sufficient lipid
layer (step 124).
[0189] Just as discussed above in the flowchart of FIG. 18 where
only RF energy is applied, the application of RF energy may be
regulated. Regulated RF energy can include controlling the
application of RF energy according to a temperature profile. The
temperature profile may be a constant temperature, include
ramp-ups, ramp-downs, peaks and valleys. Further, the temperature
profile may include RF energy pulses or be modulated with various
characteristics, including the use of on/off switching or pulse
width modulation (PWM) techniques for example. The use of modulated
RF energy may allow the temperature to be raised even higher at the
eyelid without damages to the patient's eyelid since the increased
temperatures are applied for shorter periods of time. Obstructions
or occlusions in the meibomian glands may have melting, loosening,
or softening points that are beyond temperatures that may be
applied without the use of modulated heat. The temperature needed
to melt, loosen, or soften obstructions or occlusions may depend on
how keratinized the obstruction or occlusion is. Not all
obstructions or occlusions have the same melting, loosening, or
softening points.
[0190] By example only, elevated temperatures between 45 and 55
degrees Celsius may be possible when directing regulated RF energy,
especially if the eyelid has been anesthetized. However, RF energy
must always be applied to the eyelid at temperatures that take into
consideration the pain response of the patient as well as whether
damage will occur to the patient's eyelid and/or surrounding
tissues. Depending on the severity of the patient's MGD or the
patient's pain tolerance, elevated temperatures may be used with
patient's on an individualized basis when directing RF energy. It
has been found that lighter skinned patients can generally tolerate
lower temperatures than darker skinned patients, and darker skinned
patients tend to exhibit less inflammation as a result of exposure
to the RF energy. Other factors, including humidity, may contribute
to a patient's tolerance of greater temperatures. For example,
humans can generally tolerate temperatures up to 70 to 80 degrees
Celsius in dry saunas where humidity is low. Application of heat in
higher humidity environments may cause pain and/or burns to occur
at lower temperatures.
[0191] Severe cases of MGD that cause substantial irritation or
risk to the patient may even call for temperatures that would
produce category one or two burns to the patient's eyelid, since
these burns generally heal. Temperatures that cause category three
burns should be avoided. In summary, treatment times and/or
temperature can be adjusted to account for these differences. The
embodiments described herein are not limited to any particular
temperature or time ranges as long as therapeutic temperature is
being applied.
[0192] The regulated RF energy can be maintained at a therapeutic
temperature for a treatment period. The treatment period can be
approximately 1 to 10 minutes for example. The RF energy could also
be repeatedly applied and maintained for a desired period of time
to keep the occlusion or obstruction in a melted, loosened, or
softened state. Either during or after such treatment by regulated
RF energy, mechanical expression of lipids and other fluids from
the meibomian glands has been found to clear obstructions which
have essentially melted or been placed in a suspension state (by
virtue of melting materials binding solids together).
[0193] Optionally, after expression of the occlusions or
obstructions is performed (step 124), an optional pharmacological
agent may be applied to the meibomian gland to promote the free
flow of sebum and/or reduce or prevent inflammation or infections
of the eye or eyelids (step 126). The discussion regarding use of
pharmacological agents above for the flowchart in FIG. 18 is
equally applicable for this embodiment and thus will not be
repeated here. Those compounds are illustrative examples of
appropriate pharmacological agents, but those skilled in the art
will appreciate that other pharmacological compounds may be
utilized.
[0194] As shown above, heating an inside surface of an eyelid to
melt, soften, or loosen obstructions within a meibomian gland
provides some advantages. Thus, in one embodiment, a force can be
applied to the outside of the eyelid while RF energy is applied via
an RF electrode on the inside of the eyelid to treat MGD. The
heating of the inner surface of the upper or lower eyelid can be
done by any convenient method. The lids can be heated one at a time
or both at once, depending on the time available to remove the
occlusions once heated. One device for heating the palpebral
conjunctiva is illustrated in FIG. 21.
[0195] FIG. 21 is a broken side view of an exemplary eyecup 80
comprising an exemplary RF electrode 32 positioned on an outer
surface of an eyelid 28. In this manner, FIG. 21 illustrates a
system where one RF electrode 32 is placed on an inner surface of
the eyelid 28. An eyecup 80 is positioned as described above. An RF
electrode 32 is positioned proximate the outer surface of eyelid
28. The eyecup 80 also comprises a support structure 98 and an
expression means 100, which may be used as a backplate to apply
pressure to express melted or softened obstructions from the
meibomian glands.
[0196] This embodiment would selectively treat via RF/microwave
energy within the tissue by creating a thermal energy at a
pre-determined distance from the RF electrode 32. The interior
location of the RF electrode 32 in this embodiment puts the energy
source closest to the meibomian gland and openings without
requiring energy transfer throughout the entire eyelid and tarsal
plate. Thereby the energy requirements for therapy and temperature
control theoretically would be less.
[0197] In addition, the treatment zone could more easily include
the entire gland length from the orifice to the gland channel and
acini. Thereby the entire duct could be heated and lipid contents
expressed as seen in the thermal gradient depicted by the triangles
134 in FIG. 21. The focus of energy would be throughout the entire
length of the duct while minimizing thermal treatment of unintended
tissues. It is important to note that the thermal gradient in this
instance would occur at the interior of the meibomian gland and not
from the exterior or orifice of the gland and then throughout the
length of the duct.
[0198] FIG. 22 illustrates an alternate apparatus for directing RF
energy or heat to the meibomian glands. In FIG. 22, the overall
device is referred to as a heat and force application device 136.
The heat may be applied via convective heat, or via the application
of RF energy as disclosed above. In this embodiment, the heat and
force application device 136 consists of a hand-held,
battery-operated controller 138 that contains heat and pressure
generating and regulation components. The controller 138 can also
be a non hand-held device that is either mounted or rests on a
table top, for example. The controller 138 as described herein is
intended to describe and encompass any device, including but not
limited to electronic and pneumatic controls and supporting
components, that is adapted to allow and control the application of
heat and/or force to the patient's eyelid. The controller 138 is
connected to a disposable component 140, via a controller interface
142, to generate heat and force at an eyelid 146, as illustrated in
FIG. 22. The disposable component 140 applies heat to the inside of
the patient's eyelid and interfaces with an eyecup to apply force
to the outside of the patient's eyelid (illustrated in FIGS.
23-26). Both can be used in concert to treat MGD for a single eye.
The interface 142 tubing can be wrapped around the patient's ear
144 with any excess clipped to the patient's clothing. The heat and
force application device 136 is intended for use by physicians to
apply localized heat and pressure therapy for treating MGD.
[0199] The controller 138 contains a user interface 148 to allow a
physician or other technician to control the heat and force
application device 136. Temperature and pressure being applied to
the patient's eyelid 146 can be seen on a temperature display 150
and a pressure display 152. By observing temperature and pressure
displays 150, 152, the physician can determine when a therapeutic
temperature and pressure have been reached. For example, the
temperature and pressure displays 150, 152 may be segment bar
graphs so that both the temperature and pressure levels and the
increasing or decreasing nature of the temperature and pressure
levels can be seen. The temperature level to be reached at the
patient's eyelid can either be set to a static level within the
controller 138, or controllable by a physician or technician. The
force and thus the pressure applied to the patient's eyelid is
controllable by squeezing a force lever 154. When a physician or
technician desires to apply force, the force lever 154 can be
squeezed. To release force and thus reduce pressure, the force
lever 154 is disengaged. The pressure created by the force applied
to the patient's eyelid is displayed on the pressure display
152.
[0200] A timer display 156 can be provided on the controller 138 to
display the amount of time that heat and/or force has been applied
to the patient's eyelid 146. The timer display 156 can display a
cumulative amount of time passed or provide a countdown timer if an
initial duration is set. For example, the timer display 156 may be
comprised of a number of seven segment displays. In one embodiment,
the timer display 156 will count down from one hundred eighty (180)
seconds and will flash at one hundred twenty (120) seconds and
sixty (60) seconds, which is an indicator to the physician to
release the force lever 154 and then reapply force and pressure by
squeezing the lever 154 again.
[0201] As illustrated in FIG. 23, the disposable element 140 is
placed on the patient's eye with the patient's upper and lower
eyelids 158A, 158B resting on the outside surface of the lens 160.
Before installation, the scleral side of the disposable element 140
may be lubricated with saline, or equivalent lubricating drops. The
disposable element 140 is then inserted onto the patient's eye
under the eyelids 158A, 158B. A heating element (not shown), which
may be an RF electrode in one embodiment, is contained within the
disposable element 140 that can direct heat to the inside of the
patient's eyelid 146 when installed. In one embodiment, an RF
electrode 32 of the type described above may be contained within
the disposable element 140 and connected to an RF energy source in
order to direct RF energy to the patient's eyelids. The material
used to construct the disposable element 140 is not electrically
conductive, but is thermally conductive to allow heat from the
heating element inside to be transferred to the patient's eyelid.
The disposable element 140 can be constructed out of a plastic,
including a clear plastic such as LEXAN HPS2 for example. Further,
the disposable element 140 can be constructed from a biocompatible
material, such as polymethylmethacrylate (PMMA), epoxy, or other
materials well known to those skilled in the art. The disposable
element 140 may be flexible, but ideally should be only minimally
compressible to fit against the patient's eyeball.
[0202] The disposable element 140 also contains a lid warmer
platform or tab 162. The lid warmer platform 162 may be connected
perpendicularly to the disposable element 140 such that it extends
away from the patient's eye when installed. The lid warmer platform
162 provides several benefits. First, it provides a handle for
insertion and movement or adjustment of the disposable element 140
and its heating element or RF electrode. Second, it provides a
guide post for a compression force device to attach to apply a
force to the patient's eyelid while the disposable element applies
heat or RF energy to the inside of the patient's eyelid. It can
also support an electrical interface 164 to allow the disposable
element 140 to electrically connect the heating element inside the
disposable element 140 to the controller 138 via the interface 142.
The controller 138 can then direct electrical or RF energy to the
heating element or RF electrode to generate heat to the inside of
the patient's eyelid when installed. Second, it provides a support
structure for interface circuitry 166. The interface circuitry 166
provides electrical connections for energizing the heating element
or RF electrode and communicating temperature measured at the
disposable element back to the controller 138 for heat or RF energy
regulation. The interface circuitry 166 will discussed later in
this application and in regard to FIG. 27.
[0203] FIG. 24 illustrates a cross-sectional view of a lid warmer
as part of the disposable element 140 to further illustrate heat or
RF energy delivery components and features of the lid warmer,
according to one embodiment. An eyelid side 168 is attached to
scleral side 170 to form lens 172. The scleral side 170 contains a
bend 174 around its circumference edge to provide an attachment
edge 176 to support attachment of the eyelid side 168. Because of
the bend 174, a hollow chamber 178 is formed. The hollow chamber
178 supports a heating element 180 contained inside the lens 172 to
generate heat when energized. In one embodiment, the heating
element 180 may be an RF electrode as described herein. In one
embodiment, the heating element 180 abuts against the eyelid side
168 so that the heat generated is located adjacent the inner eyelid
28 to apply heat to the meibomian glands. The heating element 180
is attached to the interface circuitry 166 via a fused link 182,
which is then attached to the controller 138 via the lid warmer
platform 162 being attached to the controller interface 142. In
this manner, the controller 138 can cause the heating element 180
to generate heat by applying an electrical signal to the interface
circuitry 166 which is connected to the heating element 180. If the
temperature exceeds the threshold temperature level of the fused
link 182, the link 182 would melt and create an open circuit to
disable the heating element 106 for safety reasons. Alternatively,
the fused link 182 could be a thermal link provided as an
integrated part of the heating element such that the fused link 182
would melt and create an open circuit at a given threshold
temperature.
[0204] The heating element 180 may be provided in any form or
material. In one embodiment, the heating element 180 is an RF
electrode of the type described herein. In another embodiment, the
heating element 180 may be a resistive type heater, a thick film
heater, or any one of a number of other types, such as a "flex
circuit" (etched metal on flexible substrate) well known to those
skilled in the art. The heating element 180 can be formed to the
shape of the disposable element 140. In the illustrated example,
the heating element 180 is a material that is both electrically and
thermally conductive. This may be important. The electrical
conductivity characteristic allows current to be applied to the
heating element 180 to generate resistive heat. The thermal
conductivity characteristic serves to evenly distribute the
resistive heat over the entire heating element 180 to more evenly
distribute the heat to the patient's eyelid. Without these
characteristics, it may be more difficult to regulate heat
generated by the heating element to efficiently and effectively
melt, loosen, or soften obstructions or occlusions in the meibomian
glands. Examples include the E5101 carbon-loaded polyphenylene
sulfide and the E2 liquid crystal polymer, both manufactured by
Cool Polymers, Inc.
[0205] The size of the disposable element 140 may also play a part
in the heating element 180 selection and the amount of heat it must
generate to be effective in MGD treatment. The disposable element
140 distributes heat generated by the heating element 180. A larger
disposable element 140 may distribute the heat generated by the
heating element 180 more uniformly and over a larger surface area.
Also note that the application of heat to the patient's eyelid does
not necessarily have to include an embedded heating element 180.
Heat application may be provided via an RF electrode as described
herein. In another embodiment, the heat may be provided as part of
the environment, such as air for example. The amount of heat
applied, the temperature reached at the meibomian glands as a
result, where the heat is applied on the patient's eyelid or
surrounding tissue, and the duration of heat applied can control
the selection of the heating source.
[0206] In addition to the insulation provided by the material used
to construct the disposable element 140, the disposable element 140
may also contain an integrated insulator inside the chamber 178 as
an additional measure of insulation. Insulation prevents
substantial heat from reaching the eyeball and thus protects the
cornea and sclera. As employed herein, the term "insulate" or
"insulation" is intended to include any component or material
and/or specific geometries of components or materials, wherein
there is greater resistance to thermal conduction or radiation
towards the surface of the eye than towards the eyelid. Stated
alternatively, in the insulator thermal energy radiates more easily
towards the eyelid 158A, 158B than towards the eyeball surface in
order to minimize the possibility of causing injury to the eyeball.
In the embodiment of FIG. 24, the integrated insulator is air and
is formed by the natural gap that exists by the space left by the
heating element 180 not filling up the entire volume of the chamber
178. The heating element 180 is biased according to its location in
the disposable element 140, and in particular to be located behind
the integrated insulator, to produce more heat on the insides of
the patient's eyelid than on their eyeball.
[0207] FIG. 25A illustrates an eyecup 186 that is adapted to allow
the controller 138 to apply a force to the patient's eyelids 158A,
158B in addition to heat. The eyecup 186 is a curved carrier 188
having a slot 190 that supports an inflatable bladder 192. The
inflatable bladder 192 is attached to the curved carrier 188. The
inflatable bladder 192 is then connected to the controller 138 via
a tubing 198 in the controller interface 142 (see FIG. 22) such
that the controller 138 can pump air into the tubing 198 to inflate
the inflatable bladder 192. When inflated, the eyecup 186 applies
force to the outside of the eyelid 158A, 158B while heat can be
applied via the lens 172 and heating element 180. To apply force to
the patient's eyelids 158A, 158B, the bladder 192 is inflated under
control of the controller 138. To release the force and thus reduce
pressure, the air in the bladder 192 is released by the controller
138.
[0208] When desired to be used, the lid warmer platform 162 is
inserted into an eyecup orifice or slot 190 in the eyecup 186
between a latching mechanism 194. The latching mechanism 194
provides a means to secure the lid warmer platform 162 to the
eyecup 186 when in use as well as provide an interface to
electrically connect the lid warmer electrical interface 164 to the
controller 138 via the controller interface 142. The latching
mechanism 194 is comprised of a carrier 196 having a semi-circular
carrier base 197. The carrier base 197 receives an eyecup platform
199 attached to the eyecup 186. The carrier base 197 and eyecup
platform 199 can be squeezed together like a clip to control an
opening through which the lid warmer platform 162 is inserted into
the carrier 196 when inserted into the orifice 190 of the eyecup
186. When the carrier base 197 is not squeezed against the eyecup
platform 199, the carrier opening through which the lid warmer
platform 162 is inserted closes to secure the lid warmer platform
162 to the carrier 197, and thus the eyecup 186. The eyecup
platform 199 is adapted to allow the lid warmer platform 162 to
rest on top when inserted into the eyecup orifice 190. When
inserted, the electrical interface 164 of the lid warmer contacts a
carrier interface 201, which provides an electrical connection
between the electrical interface 164 and the controller interface
76.
[0209] FIG. 25B illustrates an alternative latching mechanism 194A
to one illustrated in FIG. 25A. The latching mechanism 194A is
compressed in the horizontal plane while the eyecup 186A is moved
forward along the lid warmer tab 162A until it rests against the
outside of the patient's eyelids 158A, 158B. When the latching
mechanism 194A is released, the eyecup 186A is fixed in place in
its location along the lid warmer tab 162A. In this manner, the
patient's eyelids 158A, 158B are "sandwiched" between the lens 172
and the eyecup 186A.
[0210] FIG. 26 illustrates the interface components between the
controller 138 and the disposable component 140 and the eyecup 186,
at a system level. The controller 138 of the heat and force
application device 136 contains a pressure control system 204 and a
RF control system 206. The pressure control system 204 is the
control component within the controller 138 that controls the
pressure from the force applied to the patient's eye via the eyecup
186. The RF control system 202 is the control component within the
controller 138 that controls the heat applied to the patient's eye
via the lid warmer. The pressure control system 204 also
communicates the pressure in the tubing 198 to a pressure sensor
206 within the pressure control system 204. The pressure sensor 206
is used to determine the pressure level in the tubing 198 to
display the pressure on the pressure display 152 as well as to
provide feedback to the controller 138 to provide the various
functions and controls for the system, as will be described in more
detail below. The pressure sensor 206 also allows the recordation
of pressure data to be recorded by the controller 138, or an
external data acquisition device (not shown) coupled to the
controller 138, if desired.
[0211] FIG. 26 also illustrates more detail regarding the latching
mechanism 194 on the eyecup 186. The latching mechanism 194
facilitates providing a connection between the lid warmer 172 and
the lid warmer platform 162 and the eyecup 186, and the lid warmer
90 to the electronics wiring 203 when the eyecup orifice 190 is
slipped over to the lid warmer platform 162 to secure the eyecup
186 to the patient's eyelid. Two different types of latching
mechanism 194, 194A were previously illustrated in FIGS. 25A and
25B, either of which can be used to secure the platform 162 to the
eyecup 186, or any other type may be used.
[0212] FIG. 27 illustrates the specific wiring and supporting
circuitry that comprises the electronics wiring 203 to interface
the controller 138, and particularly the RF control system 202, to
the lid warmer to apply heat to the patient's eye for the disclosed
embodiment. Six wires make up the electronics wiring 203. The six
interface wires are connected to the interface circuitry 166 that
is embedded in the disposable component 140. In one embodiment, the
heating element 180 is an RF electrode as described herein for
directing RF energy to the meibomian glands in the eyelid. In this
embodiment, RF+ and RF- are connected to the heating element 180
(RF electrode) in the lid warmer when the platform 162 is connected
to the controller interface 142. THERM1+ and THERM2+ are coupled to
two thermistors 208A, 208B. The two thermistors 208A, 208B provide
an indication of temperature at the patient's eyelid as part of a
temperature feedback mechanism to allow the RF control system 202
to monitor the temperature for control. Because in the preferred
embodiment, the temperature drop between the heating element 180
and the inside of the patient's eyelid is minimal, regulating
temperature is simpler. This is because the thermistors 208A, 208B
record temperatures closer to the actual temperatures at the glands
and thus temperature overshooting is minimized. It is important to
attempt to minimize temperature overshoot so as to not damage the
patient's tissue. Temperature thermostats or other more complicated
regulation circuits may be employed to regulate temperature as well
if desired, especially if temperature overshooting is an issue.
Further, the size of the heating element and power supply could
also be selected so that only a known maximum amount of heat could
be generated even if the heating element 180 were energized all the
time. This would avoid use of a regulation circuit to prevent
temperature overshoot.
[0213] Two thermistors 208A, 208B are provided for redundancy and
error checking in the event one fails. Both thermistors 208A, 208B
should provide the same signal indicative of temperature. Both
thermistors are coupled to a common RETURN to provide common
current return/grounding. Lastly, a FUSE line is provided and
linked to a fuse 210, which is also coupled to the RETURN line. The
controller 138 can send a current over the FUSE line sufficient to
blow fuse 138. The controller 138 can blow the fuse 210 to provide
an indication that the lid warmer has been previously used. Thus,
if the lid warmer is reused, the controller 138 can detect the open
circuit on the FUSE line and know that the fuse 210 has been
previously blown.
[0214] FIG. 28 illustrates an alternative embodiment of an eyecup
211 that may be employed as part of treating MGD. As illustrated in
FIG. 28, an exemplary eyecup 211 provides insulation to the globe
of the eye and has localized aspiration at the location of the
meibomian glands. An eyecup that maintains a space between the
eyelid and cornea has been described previously with reference to
FIG. 24. The materials in the eyecup are non-conductive and limit
the transference of thermal energy to the globe. An inner sandwich
layer of the eyecup limits thermal energy to the globe of the eye.
The inner sandwich can be made from Aerogel in one embodiment. The
inner sandwich may be a vacuum space. In one embodiment, the inner
sandwich is filled with a non-conductive gel.
[0215] As described previously, the eyecup 211 is configured to
maintain a spacing from the cornea. In one embodiment, the eyecup
211 has an aspiration conduit 212 for aspiration means at the
meibomian gland location. The aspiration conduit 212 is connected
to external aspiration or vacuum source that is used to withdraw
material from the glands (as opposed to mechanical pressures
directed on the outside of the eyelid), as seen in FIG. 28. The
aspiration source pulls vacuum through a mesh screen 214 which is
positioned at the meibomian gland openings. Separate gutters or
projections 216 focus aspiration forces or vacuum at the meibomian
glands as seen in FIG. 29A. The gutters 216 also facilitate drug
delivery as described below.
[0216] The gutters 216 may also be configured to protrude gland
openings towards the mesh screen and aspiration forces as seen in
FIG. 29B. By applying aspiration forces at the openings of the
glands, obstructions at the orifices of the glands can be removed
once heated and loosened via aspiration means. The application of
localized aspiration reduces blood flow to the treatment area due
to mechanical force on the gutters 216, minimizing heat sink issues
of the vasculature. The aspiration source may be applied at a low
level to help maintain eyelid stability at the beginning of the
procedure in one embodiment.
[0217] Upon the application of RF/microwave energy and as the gland
duct materials begin to melt, the aspiration source may
preferentially increase to help draw materials out of the glands.
Since melted gland duct materials may be more viscous in nature,
the aspiration conduit 212 could also be a mechanism to deliver
flush fluid intermittently to help improve the transport of
aspirated materials. Thus the aspiration conduit 212 can
periodically be used to administer fluids for cleaning the
treatment area, or a separate conduit can be built into the eyecup
for delivering fluid to the treatment area. In one embodiment, the
aspiration may be pulsed in pumping-like fashion to facilitate
material removal. The material aspirated will be drawn into a
separate collection chamber for removal or analysis. It is the
object of the aspiration forces to be gentle and less traumatic to
the tissues than mechanical expression forces.
[0218] As RF energy is being applied in conjunction with
aspiration, the tissues being treated may become dried out which
would tend to diminish the capability of the RF energy to heat the
nearby tissue. It may be beneficial during the energy delivering
steps to periodically stop aspiration to lightly administer saline
or other conductive fluids to the treatment area so that a more
effective administration of RF energy can continue to be employed.
This administration of fluids can be accomplished through the
conduit for aspiration.
[0219] The aspiration conduit 212 can also be used for the
administration of topical agents and therapeutic drugs to the
glands post treatment. In one embodiment, a separate conduit from
the aspiration conduit 212 could be employed to deliver drugs to
topical agents. This administration of agents could be very useful
for patient comfort post treatment since the aspiration means
coupled with RF energy may have dried out the inner portion of the
patients' eye lid in a localized region.
[0220] In one embodiment, the gutters 216 on the eyecup 211 provide
for a more efficient administration of drug or topical agents.
[0221] The eyecup 211 acts as an insulator for the globe and it can
also be used to preferentially cool eye lid tissues that are not
populated with meibomian glands. In one embodiment, a conduit
(either conduit 212 or a separate conduit) supplies coolant media
to areas of the eyelid where heating is not desired. The coolant
media can be cryogenic materials in one embodiment. The coolant
media may also comprise continuously flowing cooled saline. In
another embodiment, coolant media can comprise flowing air, which
may also be cooled.
[0222] In another embodiment, an RF electrode or microwave antenna
is placed on both the outer and inner surfaces of the eyelid to
direct thermal energy rapidly within the meibomian glands and
selectively target gland duct contents. The microwave/RF energy is
passed through the outer or inner surfaces of the eyelid or
orifices of the meibomian glands to create a thermal energy
increase directly at the location of the gland duct contents. Two
RF electrodes or microwave antennae configured to provide microwave
or RF energy are placed on both the inner and outer eyelid(s) of a
patient. Through a direct connection with a RF or microwave
generator, or electrical surgical unit (ESU), thermal energy is
selectively delivered beneath the outer tissue layer of a patient
and to a location within tissue between two the energy delivering
RF electrodes or microwave antennae.
[0223] FIG. 30 illustrates an eyecup 80 where two RF electrodes 32A
and 32B are used. FIG. 21 is a broken side view of an exemplary
eyecup 80 comprising a pair of exemplary RF electrodes 32A, 32B.
The eyecup 80 is positioned as described above. One RF electrode
32A is placed on the outer surface of the eyelid and one RF
electrode 32B is placed on the inner surface of the eyelid. The
eyecup 80 also comprises a support structure 98 and an expression
means 100, which may be used as a backplate to apply pressure to
express melted or softened obstructions from the meibomian glands.
The expression means 100 provides a back plate against which force
may be applied. In limited circumstances when the obstruction in
the meibomian gland channel is minimal, the meibomian gland may be
cleared merely through the application of force externally applied
to the eyelid, such as gentle finger press. More specifically, with
the expression means 100 in place and the eyecup 80 behind the
eyelid, pressure may be applied to the external surface of the
eyelid, the eyelid being "sandwiched" between the expression means
100 and the eyecup 80.
[0224] In other instances, the meibomian gland obstruction may be
blocked to a degree greater than can be treated with simple
pressure alone. In such cases it is necessary to apply thermal
energy to the eyelid in order to loosen, break up, fracture, soften
or liquefy at least a portion of the occlusion. Thermal energy may
be applied by any one of the well known means for applying thermal
energy such as modalities such as resistive, IR (infrared),
ultrasonic heating, microwave, any one of the numerous "hot pads"
that chemically produce an exothermic reaction or in the simplest
form a hot compress. Experimentation has revealed that in order to
be clinically effective the eyelid should be heated to a
temperature of between about 35 degrees Celsius and 47 degrees
Celsius. The length of time for which thermal energy (i.e. heat) is
applied to the eyelid depends upon the extent that the obstruction
blocks the meibomian gland channel as well as the composition of
the obstruction. In very minor cases, heat may be applied to the
eyelid for less than three minutes or even as little as five to
fifteen seconds. On the other hand, extreme blockage may require as
much as thirty minutes of heating to melt, loosen, or soften the
obstruction prior to the application of force to the eyelid to
express the softened obstruction. Experimentation has further
revealed that the eyelids are efficient heat exchangers with
circulating blood acting as the cooling mechanism and that the
eyelid temperature returns to normal in less than two minutes at
which time the obstruction re-hardens making extraction difficult.
It is therefore necessary to apply the aforesaid expressive force
to the eyelid within that time frame in order for the treatment to
be successful. Thus, pressure, preferably in a milking type action,
to urge the obstruction upward and out of the meibomian gland
orifice should be employed. Again, depending on the nature and
location of the obstruction, mere compressive force may be
effective in some instances.
[0225] In FIG. 30, the desired amount of thermal energy to deliver
to contents within the meibomian glands is an amount sufficient to
heat the contents to between 37 and 45 degrees C. The RF energy or
microwave energy can be controlled by a controller, such as
controller 68 in FIG. 11, or by the RF generator 64 in FIG. 10, to
selectively heat the contents of the ducts and channel of the
meibomian glands to a known temperature within the tissues and/or
to selectively heat lipid containing materials. This may be done by
adjusting the power and duration of the applied RF energy, or by
changing the waveform shape (stepped or curved). The waveforms may
be pulsed or continuous waveforms. In another embodiment, the shape
of the RF electrode or microwave antenna that delivers or emits the
RF or microwave energy may be changed to selectively heat the
contents of the ducts and channel of the meibomian glands to a
known temperature within the tissues and/or to selectively heat
lipid containing materials. In this manner, the RF energy will be
applied to selectively target any obstructions within the duct,
channel, or acini of the meibomian glands to melt, soften, or
loosen such obstructions. Once melted, softened, or loosened, the
obstructions may be more easily expressed from within the channel
of the meibomian gland through an orifice of the meibomian
gland.
[0226] In the two electrode system shown in FIG. 30, the RF or
microwave energy can also be controlled by the fixed distance
between the two RF electrodes 32A, 32B. Since this distance is
fixed, the RF energy source pinpoints the wave forms within a
desired depth of the eyelid and away from the surface layer or
outermost tissue layer.
[0227] In another embodiment, the system at the inner eyelid could
contain fluid sensors which react to the presence of fluid being
expressed by the gland. As a control feedback mechanism, the energy
application can be reduced as expressed material is sensed or
collected. As part of the feedback mechanism, additional pulses of
energy could be reduced in power or stopped when no additional
fluid is collected thereby terminating the procedure.
[0228] Regardless of whether an RF electrode is placed on an outer
surface of the eyelid, an RF electrode is placed on the inner
surface of the eyelid, or an RF electrode is placed on both an
outer surface and an inner surface of the eyelid, the RF energy may
be applied to selectively target obstructions within ducts,
channels, or acini of meibomian glands in order to melt, soften, or
loosen the obstructions. Once melted, softened, or loosened, the
obstructions need to be expressed from within the channel of the
meibomian gland through an orifice of the meibomian gland.
[0229] Various mechanics of expressing the heated contents of the
meibomian gland have been described previously with the use of an
eyecup and inflation bladders, such as described in U.S.
application Ser. No. 11/434,033 entitled "Method and Apparatus for
Treating Gland Dysfunction Employing Heated Medium," filed on May
15, 2006, which claims priority to U.S. Provisional Patent
Application No. 60/700,233, filed Jul. 18, 2005, entitled "Method
and Apparatus for Treating Gland Dysfunction"; U.S. application
Ser. No. 11/434,446 entitled "Method and Apparatus for Treating
Gland Dysfunction," filed on May 15, 2006, U.S. application Ser.
No. 11/434,054 entitled "Method and Apparatus for Treating
Meibomian Gland Dysfunction," filed on May 15, 2006; U.S.
application Ser. No. 11/541,291 entitled "Method and Apparatus for
Treating Meibomian Gland Dysfunction Employing Fluid Jet," filed on
Sep. 29, 2006; U.S. application Ser. No. 11/541,418 entitled
"Treatment of Meibomian Glands," filed on Sep. 29, 2006; and U.S.
application Ser. No. 11/541,308 entitled "Melting Meibomian Gland
Obstructions," filed on Sep. 29, 2006; and U.S. application Ser.
No. 12/015,558, filed Jan. 17, 2008, entitled "Inner Eyelid
Treatment for Treating Meibomian Gland Dysfunction," all of which
are incorporated herein by reference in their entireties.
[0230] Other mechanisms for expressing melted, softened, or
loosened, obstructions from within the channel of the meibomian
gland through an orifice of the meibomian gland include compression
of the RF electrode itself on the eyelid. In this embodiment, the
eyecup becomes the foundation or "back-stop" for compression using
the RF electrode. In another embodiment, rollers or other
projections separate and independent from the RF electrodes may be
used to express the melted, softened, or loosened, obstructions
from within the channel of the meibomian gland through an orifice
of the meibomian gland. In this embodiment, the RF electrode
remains at a fixed distance and other mechanical structures, such
as rollers compress the eyelids to express the melted, softened, or
loosened, obstructions from within the channel of the meibomian
gland through an orifice of the meibomian gland. Any of these
mechanisms for expressing obstructions may be referred to as
mechanical expressors configured to express the obstruction from
the duct of the meibomian gland.
[0231] In another embodiment, direct localized aspiration using an
aspiration means on the inner eyelid surface may be used to force
the melted, softened, or loosened, obstructions from within the
channel of the meibomian gland through an orifice of the meibomian
glands.
[0232] Vibrational or ultrasonic energy may also be used to express
melted, softened, or loosened, obstructions from within the channel
of the meibomian gland through an orifice of the meibomian
glands.
[0233] In any of the RF delivery systems described herein,
temperature monitoring is useful to avoid damage to the eyelids and
surrounding tissues. Temperature monitoring could be achieved by
thermocouples at the outer surface layer. RF and microwave energy
has been known to disrupt temperature monitoring systems such as
found in thermocouples. Preferably a fiber optic temperature sensor
could be employed that advantageously is not affected by RF and
electrical energy sources. In addition, these fiber optic
temperature monitoring systems can be made very small and
inexpensively as described in other temperature sensing
applications.
[0234] Further, temperature control and feedback systems may also
be used. Temperature monitoring could be achieved by thermocouples
at the outer surface layer. RF and microwave energy has been known
to disrupt temperature monitoring systems such as found in
thermocouples. Preferably a fiber optic temperature sensor could be
employed that advantageously is not affected by RF and electrical
energy sources. In addition, these fiber optic temperature
monitoring systems can be made very small and inexpensively as
described in other temperature sensing applications.
[0235] Another method for controlling energy delivery to the
meibomian gland is through impedance monitoring. A sensitive
impedance monitoring system would be useful since the tissue itself
would not undergo high impedance changes which typically occurs
though the process of desiccation. As tissue becomes denatured
through desiccation, tissue impedance increases due to a loss of
cellular fluid. Once impedance measurements increase, energy
delivery would be automatically reduced by the use of an impedance
monitoring and feedback control system. In the meibomian gland
application, impedance measurements would need to have a high
sensitivity since the degree of desiccation would be minimal.
However, in combination with an aspiration means that continually
withdraws expressed fluid from the treatment zones, an impedance
measurement/feedback system could provide sensitive control in the
amount of energy applied to the meibomian glands in combination
with a temperature sensing mechanism or by itself.
[0236] FIG. 31 shows varying energy densities in tissue. The energy
density can be greater within the tissue rather than at the surface
of the tissue, which provides an advantage over methods and
apparatuses that apply heat to the surface and rely on the heat
being conducted through the tissue. An area 222 of thermal gradient
is created, wherein an area of greater thermal energy 224 and an
area of lesser thermal energy 226 is created by the application of
the RF energy to selectively target the internal portions of the
meibomian glands within the eyelids. In these systems, in order to
heat the contents of the meibomian gland to the desired
temperature, often the surface temperature becomes too hot for the
patient's safety and comfort. By using the RF energy to direct
thermal energy to specific points within the meibomian glands (such
as the obstructions) rather than at the surface of the eyelid, the
obstructions within the channel of the meibomian gland may be
heated to a temperature sufficient to melt, soften, or loosen the
obstruction without damaging the tissue at the surface of the
eyelid.
[0237] FIG. 32 illustrates a flowchart which describes the overall
operation and logic of the heat and force application device 136 in
FIG. 22 that is carried out by the controller 138 and its systems,
including the RF control system 202 and the pressure control system
204. The process starts by the controller 138 resetting in a reset
state (step 228 in FIG. 32). The controller 138 always starts in a
reset state in the disclosed embodiment. The reset state may occur
as a result of a power cycle or if a new disposable component 140
is connected to the controller 138. After resetting, the controller
138 performs a series of tests prior to beginning treatment to
determine if the controller 138 and its components are operating
properly (decision 230 in FIG. 32). If not, an error is noted and
the controller 138 stops operation by entering into the stop state
(step 232 in FIG. 32). The stop state disables the RF electrode. If
the controller 138 is operating properly (decision 230 in FIG. 32),
the controller 138 proceeds with the operations to begin a
treatment.
[0238] As an option, the controller 138 may first blow a fuse on
the lid warmer to create an open circuit in a fuse blow state (step
234 in FIG. 32). This is so a lid warmer cannot be reused for
subsequent treatments for safety and contamination reasons. As part
of the operation check in decision 230, the controller 138 may
determine if the fuse on the lid warmer has been blown. If so, this
would be an indication that the lid warmer has already been used,
and the controller 138 would enter the stop state (step 232 in FIG.
32). The controller 138 will continue to allow operation with the
installed lid warmer after the fuse is blown until the lid warmer
is removed. In such case, the controller 138 will enter the reset
state (step 228 in FIG. 32).
[0239] Next, the controller 138 prepares for a therapy. The
controller 138 may first initialize therapy timers in the timer and
display controller 150. Timers allow the user of the controller 138
to track the amount of time that therapy has occurred, including
heat and force application. Different patients may require
different amounts of time for the application of heat and force
during treatments. For example, a treatment cycle may include the
application of heat for three minutes, but force may need to be
applied, disengaged, and reapplied several times during the three
minute therapy time period.
[0240] Subsequently, the controller 138 enables the RF control
system 202 and the pressure control system 204 to apply heat and
force to the patient's eyelid as part of a run state (step 238 in
FIG. 32). RF energy is applied to heat the internal portions of the
meibomian glands and force may also be applied to the outside of
the patient's eyelid, as previously discussed. However, note that
the controller 138 could also be used to direct RF energy and/or
force to any part of the patient's eye or supporting structure,
including but not limited to both to the outside of the patient's
eyelid, and RF energy to the outside and force to the inside of the
patient's eyelid. The controller 138 then monitors the RF energy
and force applied to the patient's eyelid as part of the RF energy
and pressure regulation in a monitor state (step 240 in FIG. 32).
RF energy and force may be constantly applied and temperature and
pressure monitored during therapy. If an error is detected
(decision 242 in FIG. 32), the controller 138 enters the stop state
to discontinue therapy (step 246 in FIG. 32). If an error is not
detected, the process continues until either an error is detected
(decision 242 in FIG. 32) or the therapy is completed (decision 244
in FIG. 32).
[0241] Other methods and apparatuses for heating the meibomian
glands to melt, soften, and loosen obstructions within the
meibomian glands, and for expressing the melted, softened, or
loosened obstructions from within a duct, channel, or acinus of the
meibomian gland, may be used. Some non-limiting examples are
provided in FIGS. 33-37E described below.
[0242] FIG. 33 employs microdermabrasion or exfoliation to remove
any cells or cellular material that may have overgrown the gland
opening. Microdermabrasion is a process that was developed for use
in dermatology to remove dead skin cells. As shown in FIG. 33 a
probe or tip 248 is equipped with an abrasive surface 250 that is
adapted to scrape the skin. The abrasive employed is usually a
diamond power or other suitable material, well known to those
skilled in the art. An inner tube 252 having a central bore 254
includes holes defining openings 256 through which a fluid such as
air is pumped. An outer covering 258 surrounds the inner tube 252
to form an outer tube 260, but at its lower edge extends slightly
lower and is spaced from the abrasive surface 250 and a space is
defined between the lower ends of the respective inner and outer
tubes 252, 260. The outer covering 258 is connected to aspiration,
vacuum, and/or suction that operates as described herein below.
[0243] In operation, the clinician would place the abrasive tip 250
in contact over the gland orifice creating a seal between the tip
and the skin. Movement of the probe 248 would cause the abrasive
250 on the bottom of the tip to separate the cells from the skin
and the aspiration, suction or vacuum would extract the cellular
material from the vicinity of the gland opening. In addition,
depending upon the obstruction, aspiration, suction and/or vacuum
alone may be sufficient to extract the obstruction.
[0244] Additional features may also be providing to the
microdermabrasion tip such as a RF heating element 262 which could
be placed in the outer covering 258 near the tip. In one
embodiment, the RF heating element 262 may be similar to the RF
electrode 32 described above. In addition, the inner tube 252 could
be equipped such that ultrasonic energy could be delivered to the
obstruction as discussed herein above.
[0245] Another embodiment may employ a chemical agent to clean the
gland margin and to remove or exfoliate cells from the meibomian
gland orifice. For example Ophthaine.RTM. or a similar
pharmacological agent may be employed to assist in removing
epithelial cells from over the gland orifice. A probe similar to
that shown in FIG. 33 may be employed, except that the inner tube
will deliver the chemical agent and the suction applied by the
outer covering will be used to evacuate the used chemical agent and
cellular material mixture away from the gland margin. Similarly,
the heating and vibrational features discussed above may also be
included.
[0246] FIG. 34 illustrates a prototype hand held suction system
generally indicated at 264 that was constructed. The system
comprised an AC power supply 266 which powered a suction pump 268
to which tubing 270 was connected. At the opposite end of tubing
270 a probe 272 was connected. A tip 274 having a 1 mm diameter and
a 200 micron orifice was attached to the end of the probe 272. The
probe end 276 was curved for ergonomic access to the gland orifice.
In use, the tip 274 is placed on or proximate the gland orifice and
the applied vacuum is used to collect the obstruction as it exits
the orifice or may alternatively be employed to assist in
expression of the obstruction. In one embodiment, the probe may
also include a regulated RF heating element as described herein,
such as the RF electrode 32.
[0247] FIG. 35 illustrates another prototype of a hand held
apparatus generally indicated at 278. The system comprised a power
supply 280 which powered an electromagnet (not shown) which was
encased in a handle 282 that may be easily held by the clinician in
one hand. A rod 284 is mounted for reciprocating motion to the
output of the electromagnet. The throw or amount of movement of the
rod 284 is 0.5 mm in one embodiment. At the end of rod 284 is
mounted a back plate 286 which is substantially perpendicular to
the axis of rod 284. Further, a lever 288 is pivotally mounted to
rod 284 and operates to actuate a roller 290. A RF heating means or
RF heater 292 may be mounted in the back plate 286. The RF heater
292 is also provided with an appropriate power source. In one
embodiment, the RF heater may be an RF electrode and connected to
an RF generator to generate RF energy that be directed into the
eyelid to selectively target obstructions in the meibomian glands
in order to soften or melt such obstructions. In operation, the
device is positioned such that the back plate 286 is positioned
between the cornea and the back surface of the eye lid. The lever
288 is actuated such that the roller 290 comes into contact with
the front surface of the eye lid. The arc of the roller 290 is such
that the eye lid is squeezed between the foregoing. The clinician
may elect to maintain the back plate 286 and the roller under
tension for a preselected period of time to soften the obstruction.
Once the desired temperature has been reached, further pressure on
the lever 288 will cause the roller to move from the bottom of the
meibomian gland (the end away from the orifice) to the top of the
gland to express the obstruction from the gland in a "milking type"
motion. Thus, a repeatable regulated method for opening obstructed
meibomian glands is provided.
[0248] The embodiment illustrated in FIGS. 36A through 36C
illustrates a hand held apparatus generally indicated at 294. The
apparatus 294 comprises a power source 296 which may be a DC source
such as a battery or an AC source similar to those discussed herein
above. The power source 296 resides within a housing 298. The power
source 296 provides electrical current to a wave form generator 299
which powers an acoustic amplifier 302 (for example, a small audio
speaker) also located within housing 298 and mounted at an
ergonomic angle therein. The acoustic amplifier 302 is programmed
to vibrate in a wave format at a frequency of 0 to 200 Hz at an
amplitude in the range of 0.1 mm to 5 mm, 0.25 mm to 5 mm, or 0.5
mm to 5 mm. Initial experiments indicate that free air amplitude of
3-4 mm at a frequency of 60 Hz to 125 Hz is well tolerated and
after 10-30 seconds of application seems to impart a natural
numbing effect to the eyelid/gland. Mounted in operative
association atop the acoustic amplifier 302 is an annulus 304 that
floats thereon and includes a cone shaped housing 300 extending
perpendicularly away from the amplifier 302 that encloses the
amplifier 302. The end 306 of the housing 300 is adapted to mount a
variety of tips 308. For example, the tip 308 may comprise a roller
310 mounted for rotation in a cradle 311. Further, the tip 308 may
be modified to include a regulated RF heating element (not shown)
that acts to soften the obstruction. In one embodiment, the end 306
or tip 308 may include a regulated RF heating element as described
herein, such as the RF electrode 32, the RF heating element
configured to generate RF energy that be directed into the eyelid
to selectively target obstructions in the meibomian glands in order
to soften or melt such obstructions
[0249] Other tip configurations may include a vacuum for collecting
the obstruction after expression thereof from the gland and
different tip configurations to apply various contact areas and
resulting forces. Thus, it will be seen that the obstruction is
actually subjected to a pair of forces, the first being the weight
of the device itself on the gland which may be combined with
additional pressure by the health care provider pressing on the
gland plus the additional intermittent force delivered to the gland
by the vibratory or pulsatory force of the tip 308. The first force
may be a fixed constantly applied force or one that increases to a
preselected maximum. Testing has indicated that use of the
foregoing method, i.e., applying a first force to the meibomian
gland and a second pulsatile force to the meibomian gland allows
delivery of a greater quantity of energy to the obstruction while
lowering the perceived pain level to the patient. It is believed
that this is the result of an overall lower degree of localized
nerve stimulation about the orbit. Heating the gland is also
beneficial in the event softening of the obstruction is needed
prior to expression thereof. Another embodiment is shown in FIGS.
37A through 37E wherein the treatment apparatus is incorporated
into a goggle-like device, termed herein as the "hydro-oculator"
which is a device worn on the head that locates the treatment
mechanism proximate the eyelids, generally indicated at 312. The
hydro-oculator 312 comprises a flexible frame 314 having a headband
316 (which may be elastic) connected thereto at each end. Connected
to the bottom of the frame 314 is a molded housing 318 which has an
angled leg 320 which is adapted to overlie the cheek bone when the
apparatus is in use. Further, an expandable fluid or gas
impermeable container referred to herein as a bladder 322 is
positioned within the cavity defined by the space between the
housing and the lower eye lid. A pumping mechanism is provided that
facilitates movement of a fluid or gas, collectively referred to
herein as a "medium" (not shown) into and out of each of the
respective bladders 322. In one embodiment, the patient would
position the hydro-oculator 312 on his or her head such that the
leg 320 of molded housing 318 rests on the upper cheek bone as best
shown in FIGS. 37C through 37E. A regulated heated medium is pumped
into the bladders 322 causing partial expansion thereof in order to
apply a pressure to the eyelids in the range of from zero to fifty
pounds per square inch (50 psi). The bladder 322 containing the
heated medium (a water based solution being preferred) is
positioned on the eyelids over the meibomian glands for a
preselected period of time (up to thirty minutes) to soften the
obstruction. It is desirable in one embodiment to include an RF
heating element, such as RF electrode 32, in the hydro-oculator 312
in order to generate RF energy to heat the medium. In this
embodiment, the RF heating element may or may not be placed in
direct contact with the bladder or the eyelids, but may direct RF
energy into the bladder 322 to warm the medium, or may direct RF
energy directly into the eyelid to selectively target obstructions
in the meibomian glands in order to soften or melt such
obstructions, or may do both. In another embodiment, the heat
source may be placed in direct contact with the eyelids, which
thereby transmits thermal energy to the meibomian glands, in
contrast to the prior art which heats a confined space in front of
the open eye where heat could be transmitted to the ocular bulbi
structures such as the crystalline lens which introduces the
possibility of cataract formation. Thereafter, the bladder is
slowly expanded to a preselected maximum such that the force on the
gland increases from the bottom up to the top or orifice end of the
gland such that the obstruction is expressed therefrom in a
"milking" type of action. Milking may be applied at a preselected
frequency between zero and five hertz (0-5 Hz) and for a
preselected period of time, usually not more than thirty minutes.
In addition, the medium may be "pulsed", i.e., milkingly moved into
and out of the bladder to further facilitate expression of the
obstruction from the gland. Pulsing may also be achieved by
providing an external force to the bladder and transmitting the
force through the fluid into the gland. Pulsing may be applied at a
preselected frequency between zero and one hundred hertz (0-100 Hz)
for a preselected period time, usually not more than thirty (30)
minutes. A chemical or pharmacological agent may be inserted into
the meibomian gland to assist in softening the obstruction and any
of the extraction modalities mentioned above may be further
employed to assist in removing the obstruction.
[0250] Although the present application discusses and provides
devices for directing heat or RF energy and force to the eyelid to
treat MGD, many configurations are possible. Heat or RF energy and
force may be applied in a number of different combinations and
manners to treat MGD. For example, FIG. 38 illustrates an
alternative embodiment for directing RF energy and force to tissue
proximate a patient's meibomian gland to treat MGD. In this
embodiment, RF energy is applied and force is applied. RF energy is
applied to selectively target and heat the internal portions of the
meibomian glands to the desired temperature level (step 324). For
example, RF energy may be applied to raise the temperature at the
inside of the eyelid between 43-47 degrees Celsius. The RF energy
may also be regulated, meaning that a RF control means or element
is controlled to be within the temperatures and means that are safe
for the eyelid and at a sufficient temperature for melting,
loosening, or softening an occlusion or obstruction in the
meibomian gland.
[0251] A force or pressure may also be applied to tissue proximate
the patient's meibomian gland to increase the efficiency of heat
transfer. As previously described, the application of force towards
the RF electrode with the patient's eyelid "sandwiched"
therebetween provides greater surface contact between the RF
electrode and the eyelid for more efficient conductive heat
transfer. Further, the application of force reduces blood flow in
the eyelids to reduce convective heat loss through the eyelids and
allow the temperature at the meibomian glands to not only rise to
higher levels, but do so more quickly and efficiently (step
326).
[0252] In the process shown in FIG. 38, the RF energy and/or force
may be maintained for a period of time sufficient to raise the
temperature at the meibomian glands sufficient to melt, loosen, or
soften the obstructions or occlusions (step 328). The force may be
maintained after the RF energy is removed, or vice versa depending
on the treatment technique desired. Maintaining force after the RF
energy is removed may reduce convective heat loss at the meibomian
glands and thus keep the temperature level at the meibomian glands
to the therapeutic levels for more time than if the force was
removed. Maintaining the RF energy without maintaining force may be
employed to allow blood flow in the eyelids, such as between
successive treatments. For example, it may be desirable to maintain
the application of RF energy to lessen the total amount of
treatment time while applying and removing force between
treatments. Also, it may not be necessary to apply significant
amounts of force, or for the same duration as application of RF
energy, if the obstruction or occlusion is located in close
proximity to the lid margin rather than in the deeper portions of
the meibomian gland. Thereafter, either during the application of
RF energy and/or the application of force or after either,
obstructions or occlusions in the meibomian glands may be expressed
so that sebum flow is restored from the glands to establish a
sufficient lipid layer (step 330).
[0253] The force may be regulated, meaning that a force generating
means is controlled to be within the pressure ranges that are safe
to be applied to tissue proximate the meibomian glands and at
sufficient pressure to allow the temperature at the meibomian gland
to be raised sufficiently. The force may be applied during the
application of the RF energy, after the application of RF energy,
or both during and after the application of RF energy. In either
case, the force may assist in expressing occlusions or obstructions
when in a loosened, softened, or melted state from the meibomian
glands. The force may include vibratory type forces, including
those generated mechanically or using fluid type devices or
mechanisms. The level of force needed to express obstructions or
occlusions in the glands may be greatly reduced when RF energy is
applied to the obstructions or occlusions to place them in a
melted, softened, or loosened state.
[0254] The application of force can also stimulate the movement of
fluids or suspensions of occlusions or obstructions from the
glands. Embodiments described herein can be used with devices which
generally apply a regulated force or milking action to the eyelid
to express the fluids or suspensions or to otherwise mechanically
stimulate the movement of fluids from the glands. In some
instances, a small, gentle, continuous force applied to the eyelid
will assist in expression of the fluids and suspensions. Vibration
can also be used when applying force simultaneously or immediately
after the heating to further assist in the expression.
[0255] Any device may be employed to generate RF energy or heat on
the outside, inside, and/or both the outside and inside of the
patient's eyelid, including those described herein. Other devices
may be employed, such as the apparatus disclosed in U.S. Patent
Application Publication No. 2007/1016254, entitled "Method and
apparatus for treating gland dysfunction employing heated medium,"
and incorporated herein by reference in its entirety. In this
application, an apparatus is employed to apply heat to the outside
of the patient's eyelid via heated fluid transfer. Further, a gas
may be employed as opposed to fluid to apply heat to the patient's
eyelid.
[0256] Where only heat is applied, regulated heat can include
controlling heat according to a temperature profile. The
temperature profile may be a constant temperature, include
ramp-ups, ramp-downs, peaks and valleys. Further, the temperature
profile may include heat pulses or be modulated with various
characteristics, including the use of pulse width modulation (PWM)
techniques. The use of modulated heat may allow the temperature to
be raised even higher at the eyelid without damage to the patient's
eyelid since the increased temperatures are applied for shorter
periods of time. Obstructions or occlusions in the meibomian glands
may have melting, loosening, or softening points that are beyond
temperatures that may be applied without the use of modulated heat.
The temperature needed to melt, loosen, or soften obstructions or
occlusions may depend on how keratinized the obstruction or
occlusion is. Not all obstructions or occlusions have the same
melting, loosening, or softening points. By example only, elevated
temperatures between 47 and 55 degrees Celsius may be possible when
applying modulated heat, especially if the eyelid has been
anesthetized.
[0257] The regulated heat can be maintained at a therapeutic
temperature for a treatment period. The treatment period can be
approximately 1 to 10 minutes for example, since the application of
force may reduce the amount of time it takes for the heat source to
raise the temperature at the meibomian glands to the desired level.
The heat could also be repeatedly applied and maintained for a
desired period of time to keep the occlusion or obstruction in a
melted, loosened, or softened state. Either during or after such
treatment by regulated heat, mechanical expression of lipids and
other fluids from the meibomian glands has been found to clear
obstructions which have essentially melted or been placed in a
suspension state (by virtue of melting materials binding solids
together).
[0258] Optionally, after expression of the occlusions or
obstructions is performed (step 330), an optional pharmacological
agent may be applied to the meibomian gland to promote the free
flow of sebum and/or reduce or prevent inflammation or infections
of the eye or eyelids (step 332). The previous discussion in the
flowcharts of FIGS. 5, 18, and 20 regarding use of pharmacological
agents above is equally applicable for this embodiment and thus
will not be repeated here. Those compounds are illustrative
examples of appropriate pharmacological agents, but those skilled
in the art will appreciate that other pharmacological compounds may
be utilized.
[0259] Any device may be employed to generate heat on the outside
of the patient's eyelid, including those described herein. Other
devices may be employed, such as the apparatus disclosed in U.S.
Patent Application Publication No. 2007/1016254, entitled "Method
and apparatus for treating gland dysfunction employing heated
medium," and incorporated herein by reference in its entirety. In
this application, an apparatus is employed to apply heat to the
outside of the patient's eyelid via heated fluid transfer. Further,
a gas may be employed as opposed to fluid to apply heat to the
patient's eyelid.
[0260] In practice, the methods and apparatuses disclosed herein
may be used to treat MGD. A doctor or other trained professional
may carry out the following method. The patient may be positioned
within a restraining apparatus. The patient's eye lids may be
prepped with appropriate topical agents (lidocaine, antiseptic,
etc.). An eyecup as described herein may be placed on the globe of
the patient's eye. The eyelid may be placed on positioning pads or
gutters. In one embodiment, aspiration may be applied to stabilize
the eyelids once the proper position is established. The RF energy
delivering device is then placed onto the eyelid position and
locked into place. RF energy is applied to the meibomian glands
while monitoring the temperature on eyecup. Aspiration may also be
applied, during or after the application of the RF energy. The RF
energy may be cycled as determined to achieve heating of the gland
ducts and melting of gland obstructions. The doctor or trained
professional may then verify that melted materials are being
obtained within collection chamber. In one embodiment, rinse cycles
may be applied if necessary during the RF energy application and
intermittently with aspiration to improve the transport of melted
materials from the meibomian glands. In one embodiment, fluid may
be delivered into the treatment area to improve the efficiency of
RF energy in situations where the treatment and aspiration have
dried out the treatment area. At the completion of the RF energy
delivery, aspiration may be stopped. In one embodiment, after the
RF energy application and/or aspiration is completed, topical
agents or drugs may be applied if necessary through the same
aspiration conduit or through a separately supplied conduit on the
eyecup. Gutters on the eyecup may be used to improve the efficiency
of the drug delivery. The eyecup and RF energy apparatus may then
be removed from the patient.
[0261] Those skilled in the art will recognize improvements and
modifications to the preferred embodiments of the present
invention. Heat as used in this application can mean the
application of thermal energy, including RF or microwave energy.
Heat may be applied to the patient's eyelid, related structure, or
surrounding tissue using any type of thermal energy. Force may be
applied to the patient's eyelid to apply pressure to the patient's
eyelid, related structure, and/or surrounding tissue using any type
of force or force generating means or device. All such improvements
and modifications are considered within the scope of the concepts
disclosed herein and the claims that follow.
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