US20070060988A1 - Melting meibomian gland obstructions - Google Patents

Abstract

Consistent with certain embodiments, an apparatus provides regulated heat to at least one of a patient's eyelids, using a heater unit having a heating element that produces heat that is transferred to the patient's eyelid when an electrical signal is applied thereto. A temperature regulator applies an electrical signal to the heating elements in order to achieve heating of the heating elements to a specified temperature range. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Description

CROSS REFERENCE TO RELATED DOCUMENTS
• This application is a Continuation-In-Part of U.S. patent application Ser. No. 11/434,054, filed May 15, 2006 and entitled Method and Apparatus for Treating Meibomian Gland Dysfunction to Korb, et al., which claims priority benefit of U.S. Provisional Application 60/700,233, filed Jul. 18, 2005, both of which are hereby incorporated by reference.
• This application is also related to U.S. patent application Ser. No. 11/434,033, filed May 15, 2006 entitled Method and Apparatus for Treating Gland Dysfunction Employing Heated Medium, to Grenon, et al. and U.S. patent application Ser. No. 11/434,446, filed May 15, 2006 entitled Method and Apparatus for Treating Gland Dysfunction to Korb, et al., each of which are hereby incorporated by reference in their entirety.
COPYRIGHT NOTICE
• A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
FIELD
• This invention relates generally to treatment of mammalian eyes. More particularly, this invention relates to application of regulated heating of the eyelids for therapeutic purposes including, but not limited to, relieving or assisting in relieving obstruction of meibomian glands by use of heat to melt certain obstructions.
BACKGROUND
• The human body contains a number of glands including the lacrimal and meibomian glands of the eye, the sebaceous or pilo-sebaceous hair glands on the face and underarms, and the mammary glands in the breasts. These glands may malfunction due to age, irritation, environmental conditions, cellular debris, inflammation, hormonal imbalance and other causes. One common disease state of the eyelid glands is the restriction or stoppage of the natural flow of fluid out of the gland caused by an obstruction.
• 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 comprised of many mucins. The middle layer comprising the bulk of the tear film is the aqueous layer, and the outermost layer is a thin (less than 250 nm) layer comprised of many lipids known as “meibum” or “sebum”. The sebum is secreted by the meibomian glands, enlarged specialized sebaceous-type glands (hence, the use of “sebum” to describe the secretion) located on both the upper and lower eye lids, with orifices designed to discharge the lipid secretions onto the lid margins, thus forming the lipid layer of the tear film. The typical upper eyelid has about 25 meibomian glands and the lower eyelid has about 20 meibomian glands, which are somewhat larger than those located in the upper lid. The meibomian gland comprises various sac-like acini which discharge the secretion into the main central duct of the gland. The secretion then passes into the orifices which are surrounded by smooth muscle tissue and the muscle of Riolan which are presumed to aid in the expression of sebum. The meibomian gland orifices open onto the lid margin at and around the junction of the inner mucous membrane and the outer skin of the eyelids termed the mucocutaneous junction.
• Specifically, as illustrated in the above patent applications, each meibomian gland has a straight long central duct lined with four epithelial layers on the inner surface of the duct. Along the length of the central duct there are multiple lateral out-pouching structures, termed acini where the secretion of the gland is manufactured. The inner lining of each acinus differs from the main central duct in that these specialized cells provide the secretions of the meibomian gland. The secretions flow from each acinus to the duct. While it has not been established with certainty, there appears to be a valve system between each acinus and the central duct to retain the secretion until it is required, at which time it is discharged in to the central duct. The meibomian secretion is then stored in the central duct and is released through the orifice of each gland onto the lid margin. Blinking and the squeezing action of the muscle of Riolan surrounding the meibomian glands are thought to be the primary mechanism to open the orifice for the release of secretion from the meibomian gland.
• Blinking causes the upper lid to pull a sheet of the lipids secreted by the meibomian glands 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. Thus, it will be seen that a defective lipid layer or an incorrect 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”.
• Dry eye states have many etiologies. A common cause of common dry eye states is the condition known as “meibomian gland dysfunction” (MGD), a disorder where the glands are obstructed or occluded. A common cause of common dry eye states is a disorder where the glands are obstructed or occluded, usually referred to as “meibomian gland dysfunction” (MGD). 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, or any component thereof, having a solid, semi-solid or thickened congealed secretion and/or plug, leading to a compromise, or more specifically, a decrease or cessation of secretion. Also with a reduced or limited secretion the meibomian gland may be compromised by the occluded or obstructive condition as evidenced by a yellowish color indicating a possible infection state, or may be otherwise compromised so that the resulting protective lipid protective film is not adequate.
• 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. Meibomian gland dysfunction is frequently the result of keratotic obstructions which partially or completely block the meibomian gland orifices and/or the central duct (canal) of the gland, or possibly the acini or acini valves (assuming they do in fact exist) or the acini's junction with the central duct. Such obstructions compromise the secretory functions of the individual meibomian glands. More particularly, these keratotic obstructions can comprise combination of bacteria, sebaceous ground substance, dead, and/or desquamated epithelial cells, see, Korb et al., Meibomian Gland Dysfunction and Contact Lens Intolerance, Journal of the Optometric Association, Vol. 51, Number 3, (1980), pp. 243-251. While meibomitis is obvious by inspection of the external lids, meibomian gland dysfunction may not be obvious even when examined with the magnification of the slit-lamp biomicroscope, since there may not be external signs or the external signs may be so minimal that they are overlooked. The external signs of meibomian gland dysfunction without obvious lid inflammation may be limited to subtle alterations of the meibomian gland orifices, overgrowth of epithelium over the orifices, and pouting of the orifices of the glands with congealed material acting as obstructions. In severe instances of meibomian gland dysfunction 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, and pouting of the orifices.
• Hormonal changes, which occur during menopause, and particularly changing estrogen levels, can result in thickening of the oils secreted by the meibomian glands which results 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, thus resulting in a decreased secretion rate.
• When the flow of secretions from the meibomian gland is restricted due to the existence of an obstruction, cells on the eyelid margin have been observed to grow over the gland orifice thus further restricting sebum flow and exacerbating the dry eye condition. Additional factors which may cause or exacerbate meibomian gland dysfunction include, age, disorders of blinking, activities such as computer use which compromise normal blinking, contact lens wear and hygiene, cosmetic use, or other illness, particularly diabetes.
• The state of an individual meibomian gland 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 Korb, et al., “Increase in Tear Film Lipid Layer Thickness Following Treatment of Meibomian Gland Dysfunction”, Lacrimal Gland, tear Film, ad Dry Eye Syndromes, pp. 293-298, Edited by D. A. Sullivan, Plenum Press, New York (1994)). Significant chemical changes of the meibomian gland secretions occur with meibomian gland dysfunction and consequently, the composition of the naturally occurring tear film is altered, which in turn, contributes to ocular disease which is generally known as “dry eye”.
• While the tear film operates as a singular entity and all of the layers thereof are important, the lipid layer, which is secreted from the meibomian glands, is of particular significance as it functions to slow the evaporation of the underlying layers and to lubricate the eyelid during blinking which prevents dry eye.
• Thus, to summarize, the meibomian glands 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 by various mechanisms leading to so-called “dry eye syndrome”. While not the only cause, meibomian gland dysfunction (MGD) is known to be a major cause of dry eye syndrome. The disorder is characterized by a blockage of some sort within the meibomian glands or at their surface preventing normal lipid secretions from flowing from the meibomian glands to form the lipid layer of the tear film.
• Such secretions serve to prevent evaporation of the tear film and lubricate the eye and eyelids, hence their absence can cause dry eye syndrome. Obstructions or occlusions of the meibomian glands may be present over or at the orifice of the gland, in the main channel of the gland which may be narrowed or blocked, or possibly in other locations including the passages from the acini to the main channel.
• It has been theorized that the acini of the glands may have valves at their junction with the main channel of the gland. The inventors theorize that if these valves exist, they may also become obstructed in some instances leading to reduced or blocked flow from the acini. These obstructions or occlusions may have various compositions.
• In response to the foregoing, various treatment modalities have been developed in order to treat the dry eye condition, including drops which are intended to replicate and replace the natural tear film, pharmaceuticals which are intended to stimulate the tear producing cells, and various heating devices which are designed to assist in unclogging the meibomian glands. Other techniques involve manual expression of the glands.
• Eye drops such as Refresh®, Soothe® and Systane® brand eye drops are designed to closely replicate the naturally occurring healthy tear film. However, their use and administration is merely a treatment of symptoms and not of the underlying cause. Further, the use of drops is generally for an indefinite length of time and consequently, extended use can become burdensome and costly.
• Pharmaceutical modalities such as the use of tetracycline have also been suggested to treat meibomian gland dysfunction and one such treatment is disclosed in United States Patent Publication no. US2003/011426 titled “Method for Treating Meibomian Gland Disease”, U.S. Pat. No. 6,455,583 titled “Method for Treating Meibomian Gland Disease” to Pflugfelder et al. and PCT Publication No. WO 99/58131 titled “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 meibomian gland dysfunction is the result of obstruction of the gland without infection. The use of corticosteroids have also been proposed to treat meibomian gland dysfunction as disclosed in U.S. Pat. No. 6,153,607 titled “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 symptom of dry eye, as opposed to treatment of the underlying cause. Additionally, the use of topically applied androgens or androgen analogues have also been used to treat acute dry eye signs and symptoms in Keratoconjuctivitis Sicca as disclosed in U.S. Pat. No. 5,958,912 and U.S. Pat. No. 6,107,289 both titled “Ocular Therapy in Keratoconjunctivitis Sicca Using Topically Applied Androgens or TGF-β” and both issued to Sullivan.
• Most knowledgeable doctors agree that heat is beneficial in treating MGD. Depending upon the nature of the obstruction, heat may be beneficial in actually melting or loosening the obstructing material, permitting the gland to begin production and excretion of lipids and other fluids more freely. However, no good method of applying localized heat to the eyelids and controlling the amount of heat applied is presently commercially available.
• One modality for the heat treatment of meibomian gland dysfunction is disclosed in European Patent Application serial no. PCT/GB2003/004782 titled “Eyelid Margin Wipes Comprising Chemical Means for Temperature Adjustment”. As disclosed in this patent application, a wipe is provided wherein prior to use, a chemical agent is activated that will heat the wipe to about 32° C. to about 40° C. The hot wipe is then applied to the lids and manual expression can then be used to unclog the ducts. This method is not without its drawbacks in that lid irritation can be exacerbated by non-specific heating.
• Another method of heating the eyelids and meibomian glands uses near infrared (NIR) radiation. More specifically, two hard eye patches were attached to an eye mask according to the pupillary distance of the subject. The eye mask was held in place by an elastic headband. Each patch employed 19 light emitting diodes, emitting near infrared radiation from 850 nm to 1050 nm, with a peak at 940 nm. The device produced 10 mW/cm²of energy operating on electrical power. Goto, E., et al., Treatment of Non-Inflamed Obstructive Meibomian Gland dysfunction by an Infrared Warm Compression Device, British Journal of Ophthalmology, Vol. 86 (2002), pp. 1403-1407. This device is designed as a non-contact infrared heating mask using IR light emitting diodes. However, there are many potential problems with use of an IR heating mechanism. For example, the IR Heat can penetrate beyond the eyelid into the cornea which is undesirable, and could ultimately cause cataracts or other damage. Additionally, the IR mask heater places no pressure whatsoever on the eyelid (despite the description as a compression device) which we have determined is useful to expel the blockage. Moreover, tests conducted on a sample of this mask revealed that in spite of the potential dangers, the mask produced very little actual heat.
• United States Patent Publication US2004/0237969 titled “Therapeutic Eye and Eye Lid Cover” comprises a pair of goggles that are adapted to deliver heated saturated air to the eyelids and particularly to the meibomian glands, again to heat the gland. Heat treatment of the eyes is also discussed in the article titled “Tear Film Lipid Layer Thickness and Ocular Comfort after Meibomian Therapy via Latent Heat with a Novel Device in Normal Subjects by Mitra et al, published inEye, (2004) at pages 1-4.
• United States Patent Publication US2003/0233135 titled “Method and Apparatus for Preventing and Treating Eyelid Problems” to Yee attempts to clear the plugged meibomian glands by means of electrical stimulation of the muscle of Riolan which the invention presumed to aid in the expression of the meibomian gland secretion.
SUMMARY OF CERTAIN EMBODIMENTS
• It is an object of certain embodiments consistent with the present invention to provide a method and/or apparatus for regulated, selective heating of mammalian eyelids.
• It is another object of certain embodiments consistent with the present invention to provide a method and/or apparatus suitable for heating meibomian glands of the upper and/or lower eyelids of either or both eyes in order to aid in the clearing of certain types of obstructions that may be present in or about the meibomian glands.
• In one embodiment consistent with the present invention, an apparatus that provides regulated heat for treatment of a mammalian eyelid has a heater unit having a heating element that produces heat when electrical signal is applied thereto. A temperature regulator applies the electrical signal to the heating element in order to achieve heating of the heating element to a specified temperature range. An eyelid interfacing mechanism couples the heater unit to the eyelid to achieve regulated heating of the eyelid within the specified temperature range.
• An apparatus that provides regulated heat to at least one of a patient's eyelids, in a manner consistent with another embodiment, has a heater unit, and the having: a heating element having first and second surfaces that produces heat when an electrical signal is applied thereto; a thermal heat sink, coupled to the first surface of the heating element in order to transfer heat from the heating element to the eyelid; an insulator coupled to the second surface of the heating element in order to reduce heat loss from the second surface; and a back plate that couples to the insulator. A temperature regulator applies the electrical signal to the heating element in order to achieve heating of the heating elements to a specified temperature range. Goggles suitable for attaching to the patient's head and covering the eyelid of the patient with a lenspiece are provided with the lenspiece having a threaded aperture therein. A threaded shaft passes through the threaded lenspiece and coupled to the heater unit at the back plate so that the heater unit can be moved into contact with the eyelid by screwing the shaft into the aperture until contact with the eyelid is achieved.
• In another embodiment, an apparatus that provides regulated heat to at least one of a patient's eyelids has a heater unit has a heating element that produces heat that is transferred to the patient's eyelid when electrical signal is applied thereto. A temperature regulator applies the electrical signal to the heating elements in order to achieve heating of the heating elements to a specified temperature range. In certain preferred embodiments, the heating element is a resistive heating element.
• Many variations in these embodiments are possible including, but not limited to providing a sensor that senses temperature and provides temperature information to the temperature regulator. In certain embodiment the eyelid interfacing mechanism comprises goggles that are adjustably coupled to the heater unit in order to move the heater unit to achieve contact with the eyelid. The goggles may be adjustably coupled to the heater unit by a threaded connection so that a position of the heater unit can be adjusted by a threading action. In certain embodiments, the heater unit has a thermal heat sink, coupled to a surface of the heating element in order to transfer heat from the heating element to the eyelid. The thermal heat sink may be, for example, at least one of a thermally conductive rubber member, a thermally conductive silicon member, an encapsulated fluid containing member, and a solid conductive member. A thermally conductive gel, cream or liquid can be placed between the heat sink and the eyelid to enhance thermal conduction from the thermal heat sink to the eyelid.
• In certain embodiments, the heater unit may have an insulator coupled to a surface of the heating element in order to reduce heat loss from the heating unit in a direction other than a direction toward the eyelid. The thermal insulator may be one of a non-thermally conductive foam element, a non-thermally conductive rubber element, and a non-thermally conductive solid element in certain embodiments. The temperature regulator may apply a pulse width modulated electrical signal to the heating element in order to regulate the heat produced thereby, and the pulse width modulated electrical signal may be produced under control of the control processor.
• In certain embodiments, the temperature regulator may incorporate a switch that selectively applies the electrical signal to the heating element in order to regulate the heat produced thereby. The electrical signal may be at least one of a current and a voltage that is selectively applied to the heating element under control of a control processor. The heater unit may have a flexible portion that contacts the eyelid in order to conform to the eyelid or may have a rigid portion that contacts the eyelid, and wherein the rigid portion is shaped to conform to the shape of the eyelid, or a combination thereof. The heater unit may have an adhesive for attaching the heater unit directly to the eyelid or may be attached to the eyelid by use of adhesive tape.
• In certain embodiments, a user interface permits a user to establish at least one of a time and a temperature for the treatment. In certain embodiments, a mechanical energy generator generates vibration, pulsation, and/or milking action of the eyelid to stimulate secretion from the meibomian glands, wherein the vibration generator may imparts mechanical energy to the eyelid having both an amplitude and frequency.
• In certain embodiments, the specified temperature range is above 37° C. and more preferably between 44° C. and 47° C. with a target temperature of about 45° C. In certain embodiments, a timer shuts off the signal to the heater element after a specified treatment time. The treatment time can be, for example, approximately 10 to 60 minutes, and preferably about 15 minutes. In certain embodiments, a pressure sensor measures a pressure with which the heater unit is applied to the eyelid
• A method of treating at least one of a patient's eyelids with a regulated heat in a manner consistent with certain embodiments involves: placing a heating unit having a heating element in contact with the patient's eyelid; and applying a control signal to the heating element to generate heat at the heating element and transfer the generated heat to the eyelid for a prescribed time period.
• In certain embodiments, the method may further involve removing the control signal after expiration of the prescribed time period. In certain embodiments, the method may further involve installing goggles on the patient, the goggles having an adjustable eye interface containing the heating element; and adjusting the eye interface to achieve contact with the eyelid. In certain embodiments, the method may involve taping the eyepiece to the patient's eyelid using a strip of adhesive tape. In certain embodiments, the method may involve attaching the eyepiece to the patient's eyelid using a double-sided medical adhesive tape or using another form of adhesive attachment. In certain embodiments, the heat is generated to approximately 40°-50° Celsius. In certain embodiments, vibration is applied to the patient's eyelid. In certain embodiments, the prescribed time period is approximately 10 to 60 minutes. The method can be applied to upper, lower or both eyelids of one or both eyes. In certain embodiments, the method further involves measuring a pressure with which the heating unit contacts the eyelid. A tangible computer readable storage medium may store instructions that, when executed on a programmed processor, carry out appropriate portions of any of these methods.
• In certain embodiments, a method of treating a mammalian eyelid involves heating the eyelid and maintaining a prescribed temperature for at least 4 minutes and no more than 60 minutes, while simultaneously applying mechanical energy and pressure to the eyelid. In other embodiments, a method of treating at least one mammalian eyelid involves applying continuous regulated heat to the at least one mammalian eyelid for a duration no longer than 60 minutes and applying a force to the eyelid during heating or within 3 minutes following heating for the purpose of clearing meibomian gland obstructions.
• The above objects and summaries are intended to illustrate exemplary embodiments which will be best understood in conjunction with the detailed description to follow, and are not intended to limit the scope or meaning of the appended claims, which should be interpreted in light of the full teachings of the entire specification and drawings. Many other variations will occur to those skilled in the art upon consideration of the present teachings which uses a plurality of exemplary, but non-limiting example embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
• Certain illustrative embodiments depicting organization and method of operation, together with objects and advantages may be best understood by reference detailed description that follows taken in conjunction with the accompanying drawings in which:
• FIG. 1 depicts upper and lower human eyelids showing the meibomian glands.
• FIG. 2 is a cutaway view of an illustrativemeibomian gland20.
• FIG. 3 is a cutaway viewmeibomian gland20 illustrating several clogging mechanisms.
• FIG. 4 is a graph of temperature versus time.
• FIG. 5 is a graph of inner and outer eyelid temperature versus time.
• FIG. 6 is a block diagram of an eyelid heating circuit consistent with certain embodiments of the present invention.
• FIG. 7 is a block diagram of another embodiment of an eyelid heating circuit consistent with certain embodiments of the present invention.
• FIG. 8 is a goggle assembly for providing heat therapy to an eyelid in a manner consistent with certain embodiments of the present invention.
• FIG. 9 is a first embodiment of an eyelid interface assembly with a threaded interconnection to a goggle lenspiece in a manner consistent with certain embodiments of the present invention.
• FIG. 10 is a cutaway view of a first embodiment of a pressure measurement mechanism used in the eyelid interface assembly in a manner consistent with certain embodiments of the present invention.
• FIG. 11 is a second embodiment of a pressure measurement mechanism used in the eyelid interface assembly in a manner consistent with certain embodiments of the present invention.
• FIG. 12 is a third embodiment of a pressure measurement mechanism used in the eyelid interface assembly in a manner consistent with certain embodiments of the present invention.
• FIG. 13 is a second embodiment of an eyelid interface assembly with a—threaded interconnection to a goggle lenspiece in a manner consistent with certain embodiments of the present invention.
• FIG. 14 illustrates an eyelid heating assembly consistent with certain embodiments of the present invention.
• FIG. 15 illustrates another eyelid heating assembly consistent with certain embodiments of the present invention.
• FIG. 16 is another eyelid heating assembly consistent with certain embodiments of the present invention.
• FIG. 17 is an example of one embodiment of an eyelid heating assembly incorporating a vibrator in a manner consistent with certain embodiments of the present invention.
• FIG. 18 is a block diagram of a heating element control arrangement consistent with certain embodiments of the present invention.
• FIG. 19 is a block diagram of another heating element control arrangement consistent with certain embodiments of the present invention.
• FIG. 20 is a block diagram of another heating element control arrangement incorporating vibrator control in a manner consistent with certain embodiments of the present invention.
• FIG. 21 illustrates an embodiment of a heating element consistent with certain embodiments of the present invention.
• FIG. 22 illustrates another embodiment of a heating element consistent with certain embodiments of the present invention.
• FIG. 23 is a flow chart of a treatment process consistent with certain embodiments of the present invention.
DETAILED DESCRIPTION
• While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail specific embodiments, with the understanding that the present disclosure of such embodiments is to be considered as an example of the principles and not intended to limit the invention to the specific embodiments shown and described. In the description below, like reference numerals are used to describe the same, similar or corresponding parts in the several views of the drawings.
• The terms “a” or “an”, as used herein, are defined as one or more than one. The term “plurality”, as used herein, is defined as two or more than two. The term “another”, as used herein, is defined as at least a second or more. The terms “including” and/or “having”, as used herein, are defined as comprising (i.e., open language). The term “coupled”, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. The term “program” or “computer program” or similar terms, as used herein, is defined as a sequence of instructions designed for execution on a computer system. A “program”, or “computer program”, may include a subroutine, a function, a procedure, an object method, an object implementation, in an executable application, an applet, a servlet, a source code, an object code, a shared library/dynamic load library and/or other sequence of instructions designed for execution on a computer system.
• Reference throughout this document to “one embodiment”, “certain embodiments”, “an embodiment” or similar terms means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of such phrases or in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments without limitation.
• The term “or” as used herein is to be interpreted as an inclusive or meaning any one or any combination. Therefore, “A, B or C” means “any of the following: A; B; C; A and B; A and C; B and C; A, B and C”. An exception to this definition will occur only when a combination of elements, functions, steps or acts are in some way inherently mutually exclusive.
• As noted above, meibomian gland dysfunction (MGD) is known to be a major cause of dry eye syndrome. The disorder is characterized by a blockage of some sort within the meibomian glands preventing normal lipid secretions from flowing. Obstructions or occlusions of the meibomian glands may be present over or at the orifice of the gland, in the main channel of the gland which may be narrowed or blocked, or possibly in other locations including the passages from the acini to the main channel.
• It has been theorized that the acini of the glands may have valves at their junction with the main channel of the gland, and that these valves may be obstructed in some instances leading to reduced or blocked flow from the acini. These obstructions or occlusions may have various compositions.
• Referring now toFIG. 1, the location of themeibomian glands10 are shown on the upper andlower eyelids12 and14 respectively. As briefly stated herein above, the upper lid contains about 25 meibomian glands and the lower lid contains about 20 meibomian glands, with significant variation. As shown in cross-sectional view of onegland10 inFIG. 2, each gland includes a central duct orchannel18 into which the secretion flows fromacini19 and anorifice20 which opens on to the eyelid margin and through which the secretion flows in order to be added to the tear film upon blinking. It will be seen that the glands are of different size, depending upon the location in the eyelid and that theorifice20 is narrower than thecentral duct18. The orifice is an opening and not a duct or channel. The orifice is usually shut—the orifice or opening is like other openings that pass fluids or secretions and remains closed until opened for discharge. Thus technically the duct proximal to the orifice is narrower than in the main channel.
• Obstruction composition will vary with the etiology which produced it. However, the obstruction will, in most cases observed to the present, be a combination of, dead cells, bacteria, desquamated cells, desquamated cells aggregating in keratotic clusters, milky fluid, inspissated or creamy secretions, or any combination of the foregoing in solid, semi-solid and thickened forms. Referring toFIG. 3, a simplified view of exemplary obstructions togland10 are depicted. In this example, which is by no means necessarily representative of all meibomian gland obstructions, as explained above, a solid or semi-solid or thickenedplug24 is depicted which is fully occluding the duct leading toorifice20 ofgland10. Anotherobstruction26 is shown at a junction from one of the acini with the central duct. As previously noted, this may be the site of a valve in the gland structure, but embodiments consistent with the present invention should not be limited by theories of the actual meibomian gland structure.
• A number of treatment techniques have been proposed to restore these glands to normal functionality, but most doctors agree that heat is beneficial in treating MGD. Depending upon the nature of the obstruction, heat may be beneficial in actually melting or loosening the obstructing material, permitting the gland to begin production and excretion of lipids and other fluids more freely. However, no good method of applying localized heat to the eyelids and regulating the amount of heat applied has been available.
• One treatment method for applying heat to the eyelids is the use of warm water compresses. Alternatively, small thermal masses (e.g., rice or flax seed) can be used by placing material into jackets much like a bean bag. These bean bags can then be heated in a microwave and applied to the eyelid.
• These techniques are not fully satisfactory in applying localized heat to the eyelid. Hot compresses are large in size relative to the eyelid. They are also messy, uncontrolled, and time consuming. Moreover, their large size results in heating areas surrounding the eyelids which make the process uncomfortable and possibly messy and even counterproductive.
• It is also theorized that localized heating of the eyelid alone would be more beneficial than heating both the eyelid and the face surrounding the eyelids. By heating the areas outside the eyelids, more blood vessels in the face will become dilated and the blood flow to the eyelid and surrounding areas will theoretically be increased. Unfortunately, this added blood flow will tend to reduce the temperature of the eyelid by means of thermal convection through the blood stream. This is the body's natural attempt to regulate the temperature of the eyelid. Since it is desirable to keep the eyelid at a constant therapeutic temperature that is higher than normal body temperature, it follows that heating a large area is potentially counterproductive because more vessels will be dilated and more blood will be flowing, thus requiring even more heat to raise the temperature.
• By their very nature, hot compresses and bean bags do not have good temperature control. Therefore, from patient to patient and application to application, the temperature of these compresses will vary. This can potentially be hazardous or uncomfortable to the patient if the temperature is too hot and ineffective if the temperature is too low. To make matters worse, the compresses begin cooling as soon as they are placed on the eyelid and may stay in the therapeutic temperature range for only a short period of time before becoming ineffective and perhaps even serving to draw heat from the eyelid.
• One way to get around the messiness is to use small conformal thermal masses which are placed inside a “bean bag” and heated in a microwave oven. One example is the use of rice placed in a cloth bag for this purpose. While this is less messy than hot compresses, it is also less effective because the heat transfer in dry heat is much lower than wet heat. This is due the fact that air trapped between the heater and the surface being heated acts as an insulator compared to a fluid boundary which provided very good heat transfer. Additionally, because these devices depend upon the thermal mass of the device for heat transfer, the smaller the device is the less heat can be drawn from the device. Hence, by definition, any device which is heated prior to application needs to have a fairly large size in order to provide the thermal mass needed to raise the eyelid temperature before it cools down substantially.
• In accordance with certain embodiments, it is preferable that the surface applied to the eyelid have a characteristic which maintains a film of moisture between the heating device and the eyelid. Thus, the heat sink preferably maintains moisture at the eyelid interface to further facilitate heat transfer to the eyelid.
• FIG. 4 illustrates this problem in the form of a graph of temperature versus time. The therapeutic temperature range has been determined to be greater than 37° C. A range of approximately 44° C. to 47° C. is most preferable since temperatures approaching 50° C. generally becomes difficult for a human to endure and may cause unnecessary pain or minor burns. A proposed target treatment temperature is 45° C. as indicated by curve25 (which provides a good balance between comfort and efficacy).Curve25 illustrates a relatively constant 45° treatment temperature for a specified treatment time (e.g., for embodiments consistent with the present invention, 10-20 minutes is preferred, with 15 minutes currently being considered a good specified time for most patients exhibiting mild to moderate MGD. For more severe MGD, between approximately 30 to 45 minutes has been found more effective. For extremely severe MGD, approximately 30 to 60 minutes is more effective. These times are for a temperature of approximately 45 degrees C., and may potentially be increased or decreased at other temperatures. In tests, ranges between 10 and 60 minutes are generally effective.
• When hot compresses or bean bag devices are used, the results will appear something likecurves28 and30 wherecurve28 may start out higher than the therapeutic temperature range and possibly at an uncomfortable temperature level, which may even cause injury, and immediately begins to drop in temperature quickly falling below the therapeutic temperature range. When the compresses are deemed to be too cool, a new compress or bean bag is used resulting in a short time gap as the heat source is changed and then totemperature curve30. Again, this curve may start out above the therapeutic temperature range and ultimately falls to below the therapeutic temperature range. Test measurements of lid temperature rise time while heated with a continuous regulated heat source as shown inFIG. 5 shows that a hot compress or beanbag device would need to stay hot within therapeutic temperature range for at least approximately 4 minutes. If it were taken off the lid to reheat, then the lid temperature would drop back to body temperature very quickly and normally within 90 seconds (possibly within 30 seconds or so), thus requiring the hot compress to start heating the lid all over again. Clearly this method is highly inefficient and has little chance of raising and maintaining the eyelid temperature to the higher therapeutic level required.
• A number of treatment techniques have been proposed to restore these glands to normal functionality, but most doctors agree that heat is beneficial in treating MGD. Depending upon the nature of the obstruction, heat may be beneficial in actually melting or loosening the obstructing material or material binding solid particles to form the obstruction, permitting the gland to begin production and excretion of lipids and other fluids more freely. While the heat treatment methods described in the Background section hereof have been found to have many drawbacks, the heating techniques described in the above referenced copending applications have been found effective and beneficial. Generally speaking, these devices produce a regulated heating of the eyelid (as measured at the outer surface thereof) to a therapeutic temperature of between 40 and 50 degrees Celsius, and more preferably between about 44 and 47 degrees Celsius with a target temperature of 45 degrees Celsius.
• The outside skin surface of the human eyelid has been observed to be approximately 1-2 degrees Celsius cooler than body temperature, with some variation. Increasing the temperature to at least 37 can begin to provide therapeutic effect for milder cases of MGD. One preferred range for treatment is 44 to 47 degrees Celsius, with a target of 45 degrees Celsius has been found effective and comfortable to the patient. In certain embodiments, the mechanical treating is carried out during or immediately after the end of the time period, and preferably with a heated instrument so as to maintain the more fluid state of the obstruction. Even higher temperatures (e.g., 50-55 degrees Celsius) can be used (or pulsed for short periods), especially if the eyelid has been anesthetized, in which case much hotter treatment for shorter time can be used without permanent injury to the patient. Generally, higher temperatures can be used for shorter periods of time. Moreover, the temperature and time used should be individualized based on the severity of the condition and the tolerance of the patient. 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. Treatment times and/or temperature can be adjusted to account for these differences. Each of the above temperatures refer to the temperature as measured at the outer surface of the eyelid.
• Also, in certain embodiments, the patient is more comfortable when the treatment begins at a lower temperature and the temperature is raised over time. Hence, the temperature should be regulated, where regulation should be interpreted to mean the amount of continuous heat can be increased and/or decreased and delivered to the eyelid in an automated, controlled and repeatable manner. Hence, additional heat can be applied at will. The temperature profile for heat application may be a constant temperature, or may have ramp-ups, ramp-downs, peaks, valleys, can be pulsed, or can be modulated with various characteristics, etc., but such profile should be regulated so as to be repeatable. It has also been found that modulating the temperature can result in a higher average temperature than a constant temperature, and may be useful in some applications.
• This temperature can be maintained at a therapeutic temperature for a treatment period of approximately 10-60 minutes (or even beyond have been found safe and useful for some patients). 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). The above applications disclose devices which generally apply a milking action to the eyelid to express the fluids or suspensions or to otherwise mechanically stimulate the movement of fluids from the glands-such fluid now including melted or suspended materials causing the obstructions or occlusions. In some instances, just gentle continuous force applied to the eyelid will assist in expression of the fluids and suspensions, while in others vibration can be used simultaneously or immediately after the heating. For purposes of this document, the terms “melted” is to be interpreted to be inclusive of states in which solid particles remain suspended within a liquid fluid.
• Referring now toFIG. 5, a graph depicts the inner surface of an eyelid and an outer surface of an eyelid when a source of constant heat at about 45 degrees C. was applied to an example subject patient. The heater is turned on at time 0:00 and off at time 8:00 (eight minutes later). It should be noted that the circulatory system attempts to regulate the temperature of the eyelid, and blood flow increases with the application of heat. For this patient, it took approximately 4 minutes for the eyelid's outer surface to reach about 45 degrees Celsius, and the inner surface of the eyelid never reached this temperature—presumably because of the body's heat regulatory mechanisms. Hence, if a 45 degree constant heat source is used, it may take at least 4 minutes for the eyelid to reach a therapeutic temperature.
• It is also noted from this graph, that when the heat source is removed from the eyelid, the temperature drops very quickly to body temperature. In virtually all cases, this temperature will drop within 2-3 minutes, but more commonly, only about 30 seconds to 90 seconds are required for the patient's eyelid temperature to drop. In this example, the temperature dropped very quickly over the first thirty seconds after removal of the heat. During this short time period, some or all of the melted obstruction may re-solidify. Hence, if manual expression techniques are to be carried out subsequent to application of heat, the manual expression should follow immediately, or within about 90 seconds—with shorter intervals being preferred, e.g., within 30 seconds. It will thus be clear from this graph that prior techniques of using warm compresses may be substantially less effective if manual expression does not follow within an extremely short period of time. Moreover, if the compresses do not maintain their heat within a therapeutic range for at least 4 minutes or cool below a therapeutic level prior to manual expression, they may provide minimal benefit to a patient suffering from substantial obstruction.
• FIG. 6 is a block diagram depicting treatment of the meibomian glands of the eyelid, and in particular the lower eyelid, as illustrated. It is noted that this treatment (as well as the other treatments described and apparatus described herein) can be utilized or adapted for either the upper or lower eyelid, or both upper and lower eyelid for either left or right eye or both left and right eyes. In this embodiment, apower supply34 supplies power to aheat regulating circuit38, which may be of any suitable design to provide heat regulation. Thisheat regulating circuit38 applies an electrical signal such as a current (AC, DC, pulsed, programmed or modulated) to heating element42 (e.g., a flexible foil heater element that produces heating by virtue of the heat produced when current passes through a resistor, i.e., resistive heating) in order to produce a regulated temperature within the therapeutic range, for example at about 45° C. Thisheating element42 is used to generate the heat which ultimately is transferred to the eyelid for heat therapy. In the present embodiment, aheat sink46 is disposed between theheating element42 andeyelid50 ofeyeball54. Thisheat sink46 may be either, for example, a flexible silicon member that flexes (along with the heating element in some embodiments) to conform to the shape of the eyelid being treated. In one embodiment, a flexible silicone rubber pad that is relatively thermally conductive (e.g., one or twolayers 1/16 inch thick) can be used. Alternatively, theheat sink46 may be a rigid or relatively rigid thermally conductive member which is pre-shaped to closely conform to the outer surface of theeyelid50. In this embodiment, one typical size or multiple sizes may be provided to match the eyeball contour and provide therapy to both the upper an lower lids simultaneously, but could be readily adapted to treat a single eyelid of a single eye or both eyelids of a single eye, or a single eyelid of both eyes or both eyelids of both eyes.
• Theheating element42 is sandwiched between thisheat sink46 andinsulator58.Insulator58 serves to minimize heat loss from the back side of the heating element (the side furthest from the eyelid being treated) and thereby assists in channeling heat from theheating element42 through the heat sink to theeyelid50. In certain embodiments, abacking plate62 is optionally applied to the outer surface of thethermal insulator58 in order to assist in attaching the assembly to the eyelid or otherwise contacting and engaging theeyelid50, as will become clear later. In certain embodiments, a slight force illustrated byarrow66 urges the heat sink into close contact with theeyelid50 in order to more efficiently transfer thermal energy to the eyelid while also applying force to the meibomian glands to urge them to expel fluids.
• One of the reasons for using heat to treat the meibomian glands is that it has been observed that heating the meibomian glands causes materials which are causing obstructions and occlusions to essentially melt and become fluid. Thus, the heat is beneficial and the slight pressure urges the melted material that was causing the obstructions to be expelled from the meibomian gland or glands. For purposes of this document, the term “melted” is to be interpreted to be inclusive of states in which solid particles remain suspended within a liquid fluid.
• In accordance with certain embodiments, theheating element42 is realized as a flexible foil resistive heating element. Such elements comprise a flex-circuit having resistive pathways through which electrical current is passed to cause generation of resistive heat. In such heating elements, the temperature can often be monitored by measurement of the resistance of the element—which changes somewhat as the element heats up. Resistance can be measured in a number of ways including indirectly by measuring the current flow to the heating element and/or the voltage applied across it. Hence, in such heating elements as used in this particular embodiment, the primary or only mode of heat production is via direct contact of the heating unit with heat provided by resistive heating and production of potentially harmful infrared light energy is minimal or non-existent. Other types of resistive heating elements may also be used without departing from embodiments consistent with the present invention.
• The circuit depicted inFIG. 6 is basic in nature and may utilize many variations consistent with embodiments of the present invention. In one embodiment, a fixed temperature device such as that illustrated inFIG. 6 may be utilized in which theheat regulating circuit38 is factory calibrated to produce the desired constant therapeutic temperature atheating element42. This constant therapeutic temperature can be factory calibrated by measurement of the temperature and resistance of theheating element42 orheat sink46 so that a safe and therapeutic level of heat is obtained. A selection of heat settings can be provided for use by the clinician or patient. The heat regulating circuit may also incorporate a timer so that heat is applied for a specified period of time once the heating cycle starts, and the heat is terminated after the specified treatment time. In addition, the heat regulating circuit may trigger an alarm notifying the user of an end of the treatment period when the specified treatment time has expired. In general, a treatment time of about 15 minutes has been found to be satisfactory, but a great deal of variation and optimization may be possible without deviating from the present invention. Generally, times ranging between about 10 and 60 minutes are appropriate, depending upon severity of the condition and temperature, but this should not be considered limiting. Additionally, the heating element may be realized as a collection or array of heating elements without limitation. Each of these variables and others will occur to those skilled in the art upon consideration of the present teachings.
• For purposes of this document, the insulator is suitably insulative so as to tend to serve as a barrier to the escape of heat from the rear of the heater element, whereas, the heatsink should be suitably conductive so as to tend to draw heat from the heater element toward the eyelid. In embodiments consistent with the present invention, where contact with the human eyelid is desired, it is often desirable that the heat sink or other element placed in contact with the eyelid be soft and comfortable. This may limit the actual absolute thermal conductivity of that material. However, so long as there is a reasonable tendency for heat to flow through the material, it will be considered a heat sink. Similarly, the insulator, due to similar restrictions as well as size, is unlikely to resemble an ideal insulator, but keeping the heat adequately directed toward the eye with a reduction in heat loss over the bare heater element is adequate to be considered an insulator. The relative thermal conductivity of the heat sink should therefore be greater than the thermal conductivity of the insulator, and preferably it should be much greater (e.g., a factor of 10). That is, the insulator should preferably be less conductive of heat than the heat sink.
• In prototypes, the insulator had thermal conductivity of less than that of 92% rubber, which has a thermal conductivity of approximately, 0.10 W/mK (watt per meter-Kelvin) while the heat sink had a thermal conductivity of approximately 1.3 W/mK, but these conductivity values should not be considered limiting. In certain embodiments, the back plate may serve adequately to provide the function of the insulator.
• It will be appreciated by those skilled in the art that the terms “heat sink” and “thermal insulator” are relative terms that describe the tendency of a material to either absorb and transfer heat or inhibit the flow of heat. For purposes of this document, the term “heat sink” will suggest that the substance in question is a relatively good conductor of heat (compared to an insulator). For materials such as thermally conductive silicon rubber, heat conductivity is generally better than that which would be considered a thermal insulator, even though it may not be as good as a metal such as steel or aluminum. However, commercially available materials that are designed for enhanced thermal conductivity are available and are made of flexible material such as silicon rubber. Similarly, most “thermal insulators” will inherently conduct a certain amount of heat. This fact will not preclude a material from being considered a thermal insulator for purposes of this document. Thermally insulating materials such as insulating foam rubber and plastics and the like are commercially available.
• One example of thermally insulating material suitable for use in embodiments of the present invention is neoprene rubber with a thickness of approximately ⅛ to ¼ inch, but these dimensions should not be considered limiting. Thermally conductive silicone rubber materials can be obtained commercially from a number of sources including, for example, Stockwell Elastomerics, Inc. of 4749 Talbut Street, Philadelphia, Pa. 19136 as product T100.
• Referring now toFIG. 7, an alternative embodiment is depicted which is similar to that ofFIG. 6, except for the inclusion of aseparate temperature sensor70 adjacent toheating element42. This temperature sensor is shown for convenience as occupying a separate layer in the structure, but this is merely for convenience of illustration.Temperature sensor70 could be placed anywhere between theinsulator58 and theheat sink46, between theheating element42 and theheat sink46, between theheating element42 and theinsulator58, embedded within theheater element42, embedded within the heat sink, or at the surface of the eyelid without limitation, so as to read the temperature being generated by theheating element42 and/or delivered to the outer surface of the eyelid. If the heat sink and insulator properly do their job, any of these points can be used to measure the temperature that is ultimately delivered to the outer surface of the eyelid (or can be calibrated to represent the final eyelid surface temperature) to a reasonable degree of accuracy (after a settling time period). The optimum place to measure this temperature, however, is at the surface of the eyelid.
• Thetemperature sensor70 may be realized as an array of sensors in certain embodiments.Temperature sensor70 sends an electrical signal back to the regulatingcircuit38 so that theheat regulating circuit38 can monitor the actual temperature generated byheating element42. Feedback control techniques can then be utilized so that proper heating within a therapeutic range is maintained atheating element42.Temperature sensor70 may be realized in a number of ways including, but not limited to, a thermocouple (e.g., the extremely small thermocouples available from Physitemp Instruments Inc. of 154 Huron Avenue, Clifton, N.J. 07013) or a conventional miniature thermistor.
• Referring now toFIG. 8, one embodiment of a treatment device consistent with the present invention is depicted in which aseparate housing76 is used to house thepower supply34 andheat regulating circuit38. This housing can be attached by wiring78 to aheater unit80. Alternatively, thepower supply34 and heat regulating circuit can be embedded within the goggle assembly or a helmet-like assembly.Heater unit80 incorporates some or all of the elements described in FIGS.6 and/or7 (as well as variations described later) with the outer surface ofheat sink46 providing an interface to the eyelid.Heater unit80 would incorporate theheat sink46,heating element42, possiblytemperature sensor70, as well asinsulator58 andbacking plate62. One or two layers of a 1/16 inch thick silicon rubber heat sink was used in prototypes with satisfactory results. Thebacking plate62 in the present embodiment is utilized to affix aball84 to a captivating socket in the backing plate so that theheater unit80 can be rotated and otherwise adjusted with respect to a holder (e.g., goggles as will be described) to appropriately contact the eyelid to be treated. The ball is in turn connected to a threadedshaft88 which has a wing nut, thumbscrew, or other conveniently manipulatedtermination92 so that the user, clinician, nurse, physician or technician can screw the shaft in to adjust the contact with the eyelid and thereby adjust the initial pressure placed on the eyelid by the heater unit. In this embodiment, the shaft is screwed through alenspiece94 forming a part of agoggle98 which the user straps to the patient's head usingadjustable straps102 in a more or less conventional manner.
• In certain embodiments, the heat sink, or theentire heater unit80 or portions thereof may be made disposable so that the regulator and other parts may be re-used with multiple patients, while remaining sanitary.
• For purposes of this document, goggles are used as an illustrative embodiment of a holder or interfacing mechanism that keeps theheater unit80 in place, but other mechanisms are also possible. Thus, the use of the term “goggle” for descriptive purposes shall be considered to be any type of goggle, frame, headgear, goggle-like headgear, helmet, strap or other device that fits on a patient's head in any manner and can be utilized to hold a heater unit such as 80 in contact with a patient's eyelid during treatment as described herein. A goggle's lenspiece as discussed is defined as an element of the goggle or other device that is situated approximately where a lens would normally reside in front of the eye, and does not necessarily imply the presence of an actual optical lens.
• In this embodiment, goggles similar to those used for swimming can be adapted to carry theheater unit80 and hold it in proximity to the eyelid being treated during the specified treatment time. While thegoggles98 illustrated inFIG. 8 are more or less conventional goggles, such as those used for covering the eyes during swimming, any other suitable mechanism for holding theheater unit80 in place at one or more of the eyelids to be treated can be utilized, including adhesives, tapes, straps, helmets, clamps or any other suitable expedient. Each such mechanism can be considered a suitable interfacing mechanism for purposes of this document.
• Thus, an apparatus that provides regulated heat to at least one of a patient's eyelids, in a manner consistent with another embodiment, has a heater unit, and the having: a heating element having first and second surfaces that produces heat when an electrical signal is applied thereto; a thermal heat sink, coupled to the first surface of the heating element in order to transfer heat from the heating element to the eyelid; an insulator coupled to the second surface of the heating element in order to reduce heat loss from the second surface; and a back plate that couples to the insulator. A temperature regulator applies the electrical signal to the heating element in order to achieve heating of the heating elements to a specified temperature range. Goggles suitable for attaching to the patient's head and covering the eyelid of the patient with a lenspiece are provided with the lenspiece having a threaded aperture therein. A threaded shaft passes through the threaded lenspiece and coupled to the heater unit at the back plate so that the heater unit can be moved into contact with the eyelid by screwing the shaft into the aperture until contact with the eyelid is achieved.
• In certain embodiments, an apparatus that provides regulated heat to at least one of a patient's eyelids has a heater unit having a heating element that produces heat that is transferred to the patient's eyelid when electrical signal is applied thereto. A temperature regulator applies the electrical signal to the heating elements in order to achieve heating of the heating elements to a specified temperature range.
• Referring now toFIG. 9, a more detailed view of the connection of theheater unit80 to thelens piece94 is depicted. In this illustration, the layers of theheater unit80 are shown in an exaggerated form in order to provide clarity. At the outermost surface is theheat sink46 which contacts aheating element42 which may be, for example, a flexible resistive foil heater such as those manufactured and sold by Minco Corporation. Foil heaters are readily available commercially and may be provided with size and thermal properties suitable for use in thepresent heating unit80. The next layer is the insulatinglayer58 which serves to prevent heat from dissipating from the rear of theheater unit80 so that heat is maintained where it is needed in contact with the eyelid. Finally, thebacking plate62 is affixed to the backside of theinsulator58 to effect interconnection with a structure that holds theheater unit80 in proper engagement with the eyelid. In some embodiments, the back plate described later may itself be constructed of a material that has suitable insulative properties to be considered both a back plate and an insulator.
• This embodiment ofbacking plate62 includes asocket110 which receivesball84 to permit the threadedshaft88 to turn freely and to permit theheater unit80 to pivot so as to be properly interfaced with the eyelid to be treated. The threadedshaft88 passes throughlenspiece94 and is fitted in this example with agnarled knob114 which permits the user, patient, doctor, clinician, nurse, or technician to adjust the amount of pressure being applied to the eyelid to assure good contact, patient comfort, and proper therapeutic application of the heat—preferably with at least a small amount of pressure.
• A small force sensing device or mechanism can be added to set the pressure consistently. A simple version of such a device is illustrated in partial cutaway inFIG. 10. In this exemplary embodiment, a spring or material withspring characteristics104 is inserted between theball84 used in the ball joint and the threadedshaft88. Theball84 fits into theeyepiece socket110 ofFIG. 9, butball84 is now attached to ahollow tube106 instead of directly to the threadedshaft88. Thehollow tube106 hasspring104 inserted in thetube106 and the threadedshaft88 pushes against thespring104 which in turn pushes on the ball joint, thereby urging the eyepiece against the eyelid. The amount of displacement between thehollow tube106 and the threadedshaft88 provides an indication of force. Thehollow tube106 may include indicia that are revealed as pressure is reduced and concealed as pressure is increased. While the embodiment shown inFIG. 10 illustrates thehollow tube106 within a hollow end portion of theshaft88, theshaft88 could equally well be disposed within thehollow tube106. In such embodiment, the end of the threadedshaft88 may be unthreaded in order to place indicia thereupon to provide an indication of pressure. Other indicators of pressure could also be devised without departing from embodiments consistent with the present invention. Tabs can be used to captivate the tube within the shaft or vice versa as illustrated.
• Force could also be measured without the use of springs by simply installing a force gauge at a suitable location—for example, on the threadedshaft88 between the goggles and the eyepiece, or embedded within theeyepiece80 itself. This is illustrated in an exemplary embodiment shown asFIG. 11. Theforce gauge116, as illustrated, is disposed along the path that force is directed such as in a segment ofshaft88. The output signal fromforce gauge116 can then be processed electronically (for example using a control processor or other processing device) and a visual image representing an amount of force (e.g., a number or a graphical indication) displayed on a display device118).
• FIG. 12 depicts yet another mechanism for measuring force that uses thin film (or other) technology which changes colors as a function of force. This can be implemented, for example, by makingbackplate62 out of a clear material (perfect clarity is not required, so long as a color change can be discerned) and placing a thin film pressuresensitive membrane122adjacent back plate62. Thethin film membrane122 will change colors as a function of pressure. By adjusting the device to achieve a particular color a standard or otherwise known pressure can be realized.
• FIG. 13 depicts a similar configuration. However, between theinsulator58 and theheating element42, a temperature sensor shown generically aslayer70 for ease of illustration is depicted.Temperature sensor70 may, for example, be a thermistor or heat sensitive resistor whose resistance can be measured as an indication of the temperature generated atheating element42. Awiring bundle78 may carry a pair of wires to theheating element42 and a pair of wires to thetemperature sensor70 or a common wire may be utilized for bothheater42 andtemperature sensor70 so that three-wire wiring bundle78 may be utilized to interface withunit76. In practice, such a temperature sensor may in fact be mounted directly to the foil heater, theinsulator58 or theheat sink46, or embedded in theheat sink46 or at the surface of the eye.Multiple sensors70 orheating elements42 may also be used to provide more degrees of freedom of control.
• In accordance with certain embodiments, it is desirable for the foil heater orother heating element42 to provide uniform heat across the surface of the thermally conductive heat sink. Some off-the-shelf heater elements may not provide uniform heating across their surface or across the surface of the eyelid being treated due to the irregular shape of the eyelid compared to many commercial heater elements which may be round, square, rectangular or oval. However, a custom designed heating element can be provided which solves this problem by changing the location of where the heater element makes electrical connection to the foil and by appropriate mechanical arrangement of the heating element. By routing power to a tab that does not form a part of the heating element, and shaping the heating element to approximate a contour of the eyelid, the temperature gradient across theheater unit80 at the eye interface can be minimized. Preferably, the heating element is appropriately shaped to provide uniform heat across the entire eyelid with no hot spots or cold spots. The use of an appropriate thermally conducted heat sink also assists in smoothing out the temperature gradient across theheater unit80 at its interface to the eyelid. However, in certain embodiments the heat sink may be eliminated with an appropriately designed heater element.
• In prototype heater units, a commercially available Minco brand Heaterstat™ model CT198-1001R8.00L1-temperature regulator was utilized. This device has the advantage of only needing two wires to connect to a Minco brand foil heater element and provides heating current and temperature regulation to the foil heater. This can be accomplished because the Minco brand foil heater utilized in the prototype (Minco HK5207R6.5L12A—see Minco “Thermofoil Heaters” Bulletin HS-202 which is hereby incorporated by reference) acts both as a heating element and a sensor at the same time. This foil heater measures 0.3 inches by 1.5 inches and only covered an upper portion of the lower human eyelids tested. Improved heater elements are discussed later.
• In prototypes the heater was operated at a 50% duty cycle at about 3.0 volts. Higher voltages result in a lower duty cycle to achieve the same heating. As the temperature increases, the resistance of the heating element also increases. Therefore, by targeting a particular resistance value, the regulator can control the temperature of the heating element by increasing current when the temperature is too low and turning off the power when the temperature is too high. In this commercially available Heaterstat™ regulator device, temperature is regulated by applying power to the foil heater and then waiting for the temperature to drop before power is applied again in a manner similar to that used by most heater thermostats. Thus, this device provides temperature that varies within a small temperature range. With the device utilized, this temperature is within about 1° C., so this device is quite suitable for use in the present application.
• It has, however, been observed that the application of the heating unit to the eyelid results in a short-term drop at the surface temperature (depicted inFIG. 4 as an upward curve at the far left as the heater unit catches up with the heat initial loss). The Heaterstat™ brand temperature regulator used in prototypes was slow to initially compensate for the additional heat dissipation caused by contact with the eyelid, because the temperature drop at the eyelid is not initially detected until the temperature drain from the heat sink reaches the heater element for detection. This problem is addressed in the improved heater elements, discussed later, by increasing the heater area and total heat output.
• The power supply may be AC, DC, pulsed, programmed or a modulated signal, and in an experimental prototype, three series connected AA size commercial alkaline batteries were utilized. This provides a DC voltage of approximately 3.6 volts. Since the specified treatment time used in prototype experiments was approximately fifteen minutes, the battery life of approximately one hour is adequate to carry out three to four treatments without problems. However, other embodiments may also be utilized in order to optimize battery life or to provide a solution that utilizes AC power sources, rechargeable batteries and/or modulated, pulsed or programmed signals rather than DC.
• Referring now toFIG. 14, aheating unit80 consistent with certain embodiments is depicted in which again a layered sandwich style assembly is depicted with aninsulator58 providing a rearmost layer, aheating element42 providing a central layer, and athermal heat sink46 providing a front layer which will be placed in contact with the eyelid. In this embodiment, an adhesive120 is applied to the outer surface of the heat sink in order to affix the heater unit to the eyelid. In this example, the adhesive120 may be in the form of a double-sided adhesive tape which has a cover that is peeled off to reveal the adhesive in order to stick theheater unit80 to the eyelid. In the example depicted, thethermal heat sink46 may be flexible or pliable so that when pressed in place it conforms to the shape of the eyelid to provide close contact between thethermal heat sink46 and the eyelid. However, in other embodiments, the surface carrying the adhesive120 may be shaped in a manner that conforms with the up and down, as well as top left and right curvature of the eyelid to be treated. In this example,thermal heat sink46 can be rigid rather than pliable. A somewhat half-moon shape is depicted for ease of illustration, but the shape is preferably one which closely conforms to the shape of an eyelid or pair or eyelids. In particular, since the lower eyelid is generally most problematic, a suitable shape to conform to the lower eyelid is desirable.
• When using any adhesive mechanism to attach theheater unit80, it is desirable to clean and dry the surfaces to which the adhesive is applied in order to remove all body oils and the like to assure that the adhesive will stick properly. Failure to do so may result in separation of the heater unit near the edges rather than conforming with the eyes.
• A similar embodiment is depicted inFIG. 15. In this embodiment, atemperature sensor70 is embedded in a layer prior to or forming a part ofthermal heat sink46. While depicted as alayer70, the temperature sensor may be a single element temperature sensor or may be an array of temperature sensors which detects temperature across the various segments or regions of the heating element. Additionally, while a single foil heating element has been discussed heretofore, the heating element may be realized as an array of heating elements which may be individually controlled in order to provide uniform heating across the surface of the eyelid.
• FIG. 16 depicts another embodiment consistent with the present invention in which aheater unit80, such as any of those described heretofore, can be attached to the lower eyelid by use of a strip of adhesive tape, such as a single side adhesive medicaladhesive tape130, in order to hold theheater unit80 in contact with the upper or lower eyelid for treatment. Again,heater unit80 is depicted as having a relatively flat but flexible contact surface which conforms to the shape of the eyelid being treated in the example illustrated. However, an eyelid conformal shape using a morerigid heat sink46 may also be utilized without departing from embodiments consistent with the present invention.
• Referring now toFIG. 17, a further embodiment is depicted in which anexample vibrating element136 is incorporated within the apparatus. While heat and gentle pressure may facilitate excretion of the melted substances causing the occlusions or obstructions of the meibomian glands, application of gentle vibration, (for example during the entire treatment period or portions thereof such as near the end of the specified treatment time, or immediately afterwards) may further induce excretion of the melted obstructive material. In this embodiment, ageneric vibrator136 is depicted as embedded within the eyepiece. Such vibratingelement136 can be of any suitable design. There are multiple mechanisms that can be utilized to provide vibratory energy to the heated eyepiece. Examples, which should not be considered limiting, are as follows:
• • An offset motor can be used and attached to the outer surface of theeyepiece heater80 orshaft88. Some such offset motors operate by having an eccentric weight attached to the shaft that causes vibration when the motor is powered. An offset motor is used in cellular telephones and beepers to alert the user. They are readily commercially available in different sizes and can operate to produce vibrations at various different frequencies and amplitudes. An appropriate frequency and amplitude can be determined by experimentation upon consideration of this teaching.
  • Button type vibration motors can be embedded within the eyepiece or otherwise attached in a manner operative to induce vibration.
  • A small motor can be placed on the screw mechanism which attaches to the mask and heater. The motor can then be used to rotate a figure eight screw causing it to move in and out. The amount of displacement in this case is fixed but the speed (frequency) can be controlled with a micro-processor unit.
  • A small piezoelectric motor can be used to move the screw mechanism which attaches to the mask and heater. The amount of displacement and frequency of operation can be controlled with a micro-processor unit.
  • The screw attachment between the goggles and the eyelid heater can be removed and replaced with a diaphragm. The diaphragm can be placed between the goggles and the eyelid heater, attached to both. A simple pulsating air pump (or fluid pump) can be used to inflate and deflate the diaphragm thus providing mechanical motion to the eyelid heater. The amount of air and frequency of pulses can be controlled by a micro-processor unit.
• Other embodiments wherein mechanical energy, (where mechanical energy is defined as any form of mechanical pressure on the glands to apply pressure to the meibomian gland to assist in pushing the blockage or obstruction out of the gland while the obstruction is softened by heat) energy is applied using any suitable mechanism can be devised upon consideration of the present teachings. Once the heating element has served to melt the obstructions of the meibomian gland or glands, application of mechanical energy such as pulsing, vibratory energy, milking, etc. action to the eyelid will stimulate the excretion of lipids along with the now fluidic material that once constituted the obstruction.
• Referring now toFIG. 18 one mechanism for regulation of the temperature generated byheating element42 is depicted. In this embodiment,heat regulating circuit38 is implemented by use of acontrol processor160 which received feedback information fromtemperature sensor70 and utilizes this information to control aswitch164 that applies power to theheating element42 in order to regulate the temperature of theheating element42. While this embodiment depicts theheating element42 andtemperature sensor70 as being two separate devices, as previously indicated, the resistance of the heating element or other characteristics of theheating element42 can also be utilized for purposes of sensing the operational temperature of the heating element(s).Control processor160 operates using an internal or external clock (not shown) so that it may further provide control of the amount of time in which theheating element42 is activated and may provide an alarm in the event of a malfunction or in the event of the end of the specified treatment periods. Other function may also be carried out withcontrol processor160 without departing from the present invention.
• FIG. 19 depicts a further embodiment of a mechanism for regulating the temperature ofheating element42. In this embodiment, a control processor similarly controls the operation of theheating element42 based upon temperature sensed by either aseparate temperature sensor70, or by theheating element42 itself. This information is used to control apulse width modulator168. By increasing the width of the pulses produced by pulse width modulator168 (i.e., increasing the duty cycle),heating element42 will produce more heat, and reducing the width of pulses produced bypulse width modulator168 will reduce the temperature of heat generated byheating element42. Other modulation schemes, including but not limited to a variable voltage and/or variable current source may also be utilized to regulate the heating of theheater element42 without departing from the present invention. Again,control processor160 may also control other functions, as will be discussed later.
• Referring now toFIG. 20, theheater unit80 incorporates (in addition to a thermal heat sink, insulator, back plate, etc.)heating element42, along with a separate orintegral temperature sensor70 and a vibratingelement136, which all form a part of theheater unit80 which is placed in contact with the eyelid. In this embodiment, acontrol processor160 uses a temperature regulator circuit172 (such as those previously described or other design) to form aheat regulating circuit38.Power source34 supplies power both to the heating element and thecontrol processor160, as well as to analarm176 andvibrator136. In this embodiment, a user interface180 (e.g., which may incorporate display118) is supplied in which the user may interact with thecontrol processor160 in order to control various aspects of the operation of the device. In one embodiment, for example, the user interface may be utilized to adjust the treatment time. Elements of this and other embodiments may be freely interchanged without departing from the invention.
• For purposes of this document, it is useful to define vibratory energy as mechanical motion having a frequency component and amplitude component. It is currently believed to be most desirable that the frequency component be between approximately 0.1 HZ and 300 HZ including random oscillations and that the amplitude component defined as the amount of displacement which is preferably up to about 3 mm, with a currently preferred deflection being about 0.5 mm. However, this should not be considered limiting since optimization of these parameters and definition of a suitable profile may be optimized by experimentation. In one embodiment, for example, the temperature profile might be to establish a constant temperature of 45 degrees C. for 15 minutes with application of linearly increasing vibratory energy from 0.1 HZ to 300 HZ over the last five minutes and the amplitude of the vibratory energy decreasing from 3 mm to 0 mm linearly over the last five minutes. The actual profiles used can be optimized experimentally after considerations of the teachings provided herein.
• As noted earlier, the heating profile of the heater element used in prototypes produced a temperature gradient of several degrees Celsius across the eyelid. Prototypes utilized Minco Thermofoil Heater HK5207R6.5L12A. While quite functional, this heater element did not have an ideal temperature profile and thus only heated a portion of the eyelid.
• FIG. 21 depicts one example of a heater element design that is customized for heating the eyelid. Such heater element design can be readily custom fabricated by foil heater companies such as Minco of 7300 Commerce Lane, Minneapolis Minn.,55432. In this embodiment, the outside profile of the heater element is designed to fit the contour of the lower eyelid, but other designs can be devised to treat the upper eyelid or both eyelids simultaneously. One typical set of working dimensions for such a heater design is approximately 1.8 inches fordimension204, approximately 1.015 inches fordimension208 and approximately 0.375 inches for thetab212 atdimensions214 and216. Of course, these dimensions should not be considered limiting, but are believed to be suitable for an average sized human eyelid. This design providestab212 that is bent back at about 90 degrees away from the eyelid and provides for attachment of wires. Additionally,tab212 and the shape of the foil heater reduces the unevenness of heating across the eyelid noted in standard commercial foil heaters that were tested.
• In accordance with certain embodiments, theheater unit80, e.g. as inFIG. 20 may be attached with wires and a plug connection to the regulator, so that theheater unit80 may be detached for cleaning, or for disposal of a portion of (e.g., the heat sink), or theentire heater unit80. In this manner, sanitation can be maintained while portions of the apparatus can be reused, and speed of treatment enhanced.
• The heating is resistive heating produced by the resistance of the conductive path between the conductors that terminate attab212. In this embodiment, the heating path meanders left to right and right to left to provide the resistive path producing the heat. In other embodiments, the resistive path can meander up and down and down and up to produce the resistive path as depicted inFIG. 22. Many other patterns can also be used. The dimensions and precise layout of the paths are designed to maintain distance between conductors, line width and resistance appropriate to generate the required heat with an even heating profile, utilizing conventional design principles for foil heater or other resistive heater designs. Moreover, other heating technologies other than foil heaters and other than resistive heating can be used without departing from the present invention.
• Those skilled in the art will appreciate upon consideration of the present teachings that many variations in the embodiments depicted are possible without departing from the present invention. For example, the heating element should preferably provide uniform heat across the eyelid, and this may be accomplished using an array of heating elements rather than a single heating element. The heating element is preferably a flexible heating element, such as a foil heating element, to assist with conforming to the shape of the eyelid. However, the heating element may also be rigid and provided in preformed shapes to conform with one average or a variety of eyelid shapes and sizes. Alternatively, a rigid heating element may be accompanied by a soft heatsink which would conform to the eyelid. As discussed earlier this heatsink can be made of a thermally conductive rubber, a fluid, gel or air filled diaphragm a damp cloth or any number of materials which would be thermally conductive and readily conformable.
• The heat sink may be made of thermally conductive rubber or silicon or can be an encapsulated fluid or gelatin. In other embodiments, the heat sink can be a solid thermally conductive material which is appropriately shaped to conform to the eyelid geometry (i.e., conform to a surface that is approximately a section of an oblique spheroid). The thermally insulatingelement58 can be made from a nonconductive rubber or foam material (where nonconductive is intended to mean low thermal conductivity) or may be made from a low thermal conductivity solid material. The heating element may be used in conjunction with a thermal conductive gel, liquid, or cream to fill gaps between the heat sink and eyelid in order to provide a more uniform conductive boundary between the eyelid and the heater unit. Alternatively, sweat produced from heating the lids inherently assists in increasing heat transfer and is a byproduct using a nonabsorbent heat sink like thermally conductive silicon rubber. The layers depicted can be integrated together in any suitable manner and may take any other form suitable to the end purpose of providing relatively uniform regulated heating of the eyelid.
• The regulating element which regulates temperature of theheating element42 and, if present, thevibratory element136 may be operated under computer control and may have temperature set points and vibratory set points including amplitude and frequency that are adjustable by the user. Additionally, if desirable, a variety of temperature profiles and/or mechanical energy profiles can be implemented under computer control where the temperature and the vibratory energy can be ramped up and/or down over time if this is deemed to be a desirable control feature. The temperature regulator and/or mechanical energy element can also operate on a timer to limit the time limit of the treatment. While pulse width modulation and simple on/off switching have been disclosed for regulating the temperature of the heating element, other embodiments will occur to those skilled in the art upon consideration of the present teaching. In according with certain embodiments, this heat regulation and/or mechanical energy regulation may be carried out under control of a computer such as a microprocessor operating under control of a computer program stored as instructions in an electronic computer readable storage medium such as a read only memory (ROM) or other suitable storage medium.
• Thepower supply34 may be based upon batteries which may be replaceable or rechargeable, or the power source may utilize AC power which is converted to DC as needed for implementation of the device.
• Any suitable mechanism can be utilized for attaching the heater unit to the eyelid. As disclosed above, this can be done with double stick medical tape or with a head piece, such as goggles, to hold the heater unit in place. In other embodiments, the heating unit may be strapped in place, held in place by the bridge of the nose, swiveled into place, screwed into place by means of a goggle mechanism, latched into placed, or utilizing any other suitable adjustment mechanism from goggles or other head gear. Such mechanism serves to adjust the amount of force placed on the eyelid from the heater unit. In other embodiments, a mechanism may also be devised which automatically adjusts the force placed on the eyelid, and the mechanism may be included either within theheater unit80 or otherwise coupled to the heater unit80 (for example, in the goggles) to transmit mechanical energy to theheater unit80.
• Thus, consistent with certain embodiments, an apparatus provides regulated heat to at least one of a patient's eyelids, using a heater unit having a heating element that produces heat that is transferred to the patient's eyelid when electrical signal is applied thereto. A temperature regulator applies an electrical signal to the heating elements in order to achieve heating of the heating elements to a specified temperature range.
• With reference toFIG. 23, one can envision any number of treatment regimens that can be carried out using the various embodiments disclosed. This flow chart depicts the general process one would go through to carry out a treatment in accordance with certain embodiments starting at250. At254, the heater unit is installed onto the patient (e.g., using the goggle arrangement or adhesive arrangements depicted). In those embodiments in which pressure can be applied, the pressure is adjusted to urge the heater unit into contact with the eyelid or eyelids to be treated with a selected measure of gentle force. The heater unit can then be turned on and the treatment cycle begins according to a manual or automated process at258.
• Once the heater unit reaches an appropriate treatment temperature (e.g., 45 degrees C.), feedback control is utilized to maintain the heat at a constant level or to achieve a desired heat treatment profile at262. Similarly, at a desired timing of the treatment profile, mechanical energy can be added (if the embodiment of the heater unit is so equipped) at266. It currently appears that best results can be achieved when mechanical energy is applied when the therapeutic temperature is reached and discontinued shortly after the heat therapy is completed. This process proceeds according to the selected treatment profile (either selected by an operator or pre-programmed) until the treatment profile is complete at270. The treatment then either ends at274 or proceeds with additional treatment modalities (e.g., manual expression).
• Thus, a method of treating at least one of a patient's eyelids with a regulated heat in a manner consistent with certain embodiments involves: placing a heating unit having a heating element in contact with the patient's eyelid; and applying a control signal to the heating element to generate heat at the heating element and transfer the generated heat to the eyelid for a prescribed time period.
• Referring back toFIG. 8, in use the patient needs only to put on thegoggles98 as one would normally wear swimming goggles and then adjust the set screw (the threaded shaft) until the heater unit comes in contact with the eyelid at a comfortable level of force. At this point, the device is ready for operation and can simply be turned on to begin the treatment. In prototypes and in the preferred implementation, the threaded shaft, back plate, gnarled knob, and other features of the adjustment mechanism are made of nylon and are easily adjustable by the patient, technician, physician, or nurse to apply an appropriate amount of pressure to the eyelid. By placing a small amount of static pressure on the eyelid during treatment, secretions from the meibomian gland are encouraged as the obstruction is dissolved by the heat. In experiments, the amount of pressure used in devices as described in the above-referenced and incorporated by reference applications utilized pulsating pressure ranging up to about 30 lb/in², with more common ranges being about 2-10 lb/in². Pulsating pressure can generally be more effective and better tolerated at higher average pressures than an equivalent static pressure. It is therefore anticipated that pressure in the range of up to 2 lb/in²will be suitable for use as static pressure, with greater pressures being usable in conjunction with other forms of mechanical energy such as vibration, pulsation, and/or milking actions and the like as described above. (For reference, when meibomian glands are manually expressed by squeezing between, e.g., an instrument and a human finger, pressure can reach several hundred pounds per square inch.)
• Hence, in the devices disclosed, localized heating of the eyelid only can be obtained so as not to dilate the blood vessels of surrounding facial tissue. When a silicon rubber heat sink is used to transmit heat to the eyelid, a thin layer of sweat develops which appears to enhance heat transfer. The treatment technique is simple and easily implemented and may even be utilized by the patient himself or herself to provide an at-home therapy to supplement treatment that may be administered by a medical professional and to assist in keeping the lipids produced in the meibomian glands flowing freely. Since the heat generated is constant or can be regulated to a specified profile, the problems associated with using dry heat, bean bags, or hot, wet compresses are ameliorated. In addition, the device is easily transported, may be operated on batteries if desired, and can be programmed to provide the appropriate amount of heat for the appropriate amount of time.
• Additionally, the mess associated with hot compresses and the inconsistent temperature profiles associated with hot compresses and the IR heating approach provided thereby, along with the danger of overheating, is minimized. Since theheating unit80 is small and lightweight, it can be attached to the eyelid using any of a number of methods depending upon the particular patient and other factors. When attached to the lower eyelid, the device can be used with the eye open. This allows the patient to perform some simple tasks (e.g., reading or watching television) while undergoing treatment in order to pass the time. In addition, the constant pressure applied to the eyelid aids in the excretion of meibomian gland lipids and other fluids as the obstruction is melted. In embodiments utilizing mechanical energy devices, the vibrating, pulsing and or milking action further assists in clearing obstructions.
• Those skilled in the art will recognize, upon consideration of the above teachings, that certain of the above exemplary embodiments are based upon use of a programmed processor. However, the invention is not limited to such exemplary embodiments, since other embodiments could be implemented using hardware component equivalents such as special purpose hardware and/or dedicated processors. Similarly, general purpose computers, microprocessor based computers, micro-controllers, optical computers, analog computers, dedicated processors, application specific circuits and/or dedicated hard wired logic may be used to construct alternative equivalent embodiments. It will also be noted by those skilled in the art that certain embodiments may require conversions from the digital to the analog domain and vice versa. Such conversion devices as D/A and A/D converters may be used as required to make such conversions, but are omitted from the drawings for clarity.
• Certain embodiments of methods described herein, are or may be implemented using a programmed processor executing programming instructions that are broadly described above, e.g., in flow chart or descriptive form, and that can be stored on any suitable electronic or computer readable storage medium and/or can be transmitted over any suitable electronic communication medium. However, those skilled in the art will appreciate, upon consideration of the present teaching, that the processes described above can be implemented in any number of variations and in many suitable programming languages without departing from embodiments of the present invention. For example, the order of certain operations carried out can often be varied, additional operations can be added or operations can be deleted without departing from certain embodiments of the invention. Error trapping can be added and/or enhanced and variations can be made in user interface and information presentation without departing from certain embodiments of the present invention. Such variations are
• Software and/or firmware embodiments may be implemented using a programmed processor executing programming instructions that in certain instances are broadly described above in flow chart form that can be stored on any suitable electronic or computer readable storage medium (such as, for example, disc storage, Read Only Memory (ROM) devices, Random Access Memory (RAM) devices, network memory devices, optical storage elements, magnetic storage elements, magneto-optical storage elements, flash memory, core memory and/or other equivalent volatile and non-volatile storage technologies) and/or can be transmitted over any suitable electronic communication medium. However, those skilled in the art will appreciate, upon consideration of the present teaching, that the processes described above can be implemented in any number of variations and in many suitable programming languages without departing from embodiments of the present invention. For example, the order of certain operations carried out can often be varied additional operations can be added or operations can be deleted without departing from certain embodiments of the invention. Error trapping can be added and/or enhanced and variations can be made in user interface and information presentation without departing from certain embodiments of the present invention. Such variations are contemplated and considered equivalent.
• While certain illustrative embodiments have been described, it is evident that many alternatives, modifications, permutations and variations will become apparent to those skilled in the art in light of the foregoing description.

Claims (90)

1. An apparatus that provides regulated heat for treatment of a mammalian eyelid, comprising:

a heater unit having a heating element that produces heat when electrical signal is applied thereto;

a temperature regulator that applies the electrical signal to the heating element in order to achieve heating of the heating element to a specified temperature range; and

an eyelid interfacing mechanism that couples the heater unit into contact with the eyelid to achieve regulated heating of the eyelid within the specified temperature range.

2. The apparatus according toclaim 1, further comprising a sensor that senses temperature and provides temperature information to the temperature regulator.

3. The apparatus according toclaim 1, wherein the eyelid interfacing mechanism comprises goggles that are adjustably coupled to the heater unit in order to move the heater unit to achieve contact with the eyelid.

4. The apparatus according toclaim 3, wherein the goggles are adjustably coupled to the heater unit by a threaded connection so that a position of the heater unit can be adjusted by a threading action.

5. The apparatus according toclaim 1, wherein the heater unit further comprises a thermal heat sink, coupled to a surface of the heating element in order to transfer heat from the heating element to the eyelid.

6. The apparatus according toclaim 5, wherein the thermal heat sink is selected from the group consisting of a thermally conductive rubber member, a thermally conductive silicon member, an encapsulated fluid containing member, and a solid conductive member.

7. The apparatus according toclaim 5, wherein one of a thermally conductive gel, cream or liquid is placed between the heat sink and the eyelid to enhance thermal conduction from the thermal heat sink to the eyelid.

8. The apparatus according toclaim 1, wherein the heater unit further comprises an insulator coupled to a surface of the heating element in order to reduce heat loss from the heating unit in a direction other than a direction toward the eyelid.

9. The apparatus according toclaim 8, wherein the thermal insulator is selected from the group consisting of a non-thermally conductive foam element, a non-thermally conductive rubber element, and a non-thermally conductive solid element.

10. The apparatus according toclaim 1, wherein the temperature regulator applies a pulse width modulated electrical signal to the heating element in order to regulate the heat produced thereby.

11. The apparatus according toclaim 10, further comprising a control processor and wherein the pulse width modulated electrical signal is produced under control of the control processor.

12. The apparatus according toclaim 1, wherein the temperature regulator comprises a switch that selectively applies the electrical signal to the heating element in order to regulate the heat produced thereby.

13. The apparatus according toclaim 1, comprising a control processor and wherein the electrical signal comprises at least one of a current and a voltage that is selectively applied to the heating element under control of the control processor.

14. The apparatus according toclaim 1, wherein the temperature regulator supplies a fixed continuous power to the heater element.

15. The apparatus according toclaim 1, wherein the heater unit has a flexible portion that contacts the eyelid in order to conform to the eyelid.

16. The apparatus according toclaim 1, wherein the heater unit has a rigid portion that contacts the eyelid, and wherein the rigid portion is shaped to conform to the shape of the eyelid.

17. The apparatus according toclaim 1, wherein the heater unit further comprises an adhesive for attaching the heater unit directly to the eyelid.

18. The apparatus according toclaim 1, wherein the heater unit is attached to the eyelid by use of adhesive tape.

19. The apparatus according toclaim 1, further comprising a user interface that permits a user to establish at least one of a time and a temperature for the treatment.

20. The apparatus according toclaim 1, further comprising a mechanical energy generator that generates a force on the eyelid to stimulate secretion from the meibomian glands, wherein the generator imparts mechanical energy to the eyelid having both an amplitude and frequency.

21. The apparatus according toclaim 1, wherein the specified temperature range is greater than 37° C.

22. The apparatus according toclaim 1, wherein the specified temperature range is between 44° C. and 47° C.

23. The apparatus according toclaim 1, wherein the specified temperature range comprises a range of temperatures surrounding about 45° C.

24. The apparatus according toclaim 1, further comprising a timer that shuts off the signal to the heater element after a specified treatment time.

25. The apparatus according toclaim 24, wherein the specified treatment time is approximately 10 to 60 minutes.

26. The apparatus according toclaim 24, wherein the specified treatment time is greater than 10 minutes.

27. The apparatus according toclaim 1, further comprising a pressure sensor that measures a pressure with which the heater unit is applied to the eyelid.

28. The apparatus according toclaim 1, wherein a portion of the eyelid interface mechanism is disposable.

29. The apparatus according toclaim 1, further comprising an adjustment which sets the amount of pressure the heater applies to the eye lid.

30. An apparatus that provides regulated heat to at least one of a patient's eyelids, comprising:

a heater unit having:

a heating element having first and second surfaces that produces heat when an electrical signal is applied thereto;

a thermal heat sink, coupled to the first surface of the heating element in order to transfer heat from the heating element to the eyelid;

an insulator coupled to the second surface of the heating element in order to reduce heat loss from the second surface; and

a back plate that couples to the insulator;

a temperature regulator that applies the electrical signal to the heating element in order to achieve heating of the heating elements to a specified temperature range;

goggles suitable for attaching to the patient's head and covering the eyelid of the patient with a lenspiece, the lenspiece having a threaded aperture therein; and

a threaded shaft passing through the threaded lenspiece and coupled to the heater unit at the back plate so that the heater unit can be moved into contact with the eyelid by screwing the shaft into the aperture until contact with the eyelid is achieved.

31. The apparatus according toclaim 30, further comprising a sensor that senses temperature and provides temperature information to the temperature regulator.

32. The apparatus according toclaim 30, further comprising a pressure sensor that measures a pressure with which the heater unit contacts the eyelid.

33. The apparatus according toclaim 30, wherein the thermal heat sink is selected from the group consisting of a thermally conductive rubber member, a thermally conductive silicon member, an encapsulated fluid containing member, and a solid conductive member.

34. The apparatus according toclaim 31, wherein one of a thermally conductive gel, cream or liquid is used to enhance thermal conduction from the thermal heat sink to the eyelid.

35. The apparatus according toclaim 30, wherein the insulator is selected from the group consisting of a non-thermally conductive foam element, a non-thermally conductive rubber element, and a non-thermally conductive solid element.

36. The apparatus according toclaim 30, wherein the temperature regulator applies a pulse width modulated signal to the heating element in order to regulate the heat produced thereby.

37. The apparatus according toclaim 36, further comprising a control processor and wherein the pulse width modulated signal is produced under control of the control processor.

38. The apparatus according toclaim 30, wherein the temperature regulator comprises a switch that selectively applies the electrical signal to the heating element in order to regulate the heat produced thereby.

39. The apparatus according toclaim 3, comprising a control processor and wherein at least one of a current and a voltage is applied to the heating element under control of the control processor.

40. The apparatus according toclaim 30, wherein the temperature regulator supplies a fixed continuous power to the heater element.

41. The apparatus according toclaim 30, wherein the heater unit has a flexible portion that contacts the eyelid in order to conform to the eyelid.

42. The apparatus according toclaim 30, wherein the heater unit has a rigid portion that contacts the eyelid, and wherein the rigid portion is shaped to conform to the shape of the eyelid.

43. The apparatus according toclaim 30, further comprising a user interface that permits a user to establish at least one of a time and a temperature for the treatment.

44. The apparatus according toclaim 30, further comprising a vibration generator that generates vibration of the eyelid to stimulate secretion from the meibomian glands.

45. The apparatus according toclaim 30, wherein the specified temperature range is greater than 37° C.

46. The apparatus according toclaim 30, wherein the specified temperature range comprises a range of temperatures surrounding about 45° C.

47. The apparatus according toclaim 30, further comprising a timer that shuts off the signal to the heater element after a specified treatment time.

48. The apparatus according toclaim 30, wherein the specified treatment time is approximately 10 to 60 minutes.

49. The apparatus according toclaim 30, wherein the heating element comprises a resistive heating element.

50. The apparatus according toclaim 30, where in a portion of the eyelid interface mechanism is disposable.

51. The apparatus according toclaim 30, further comprising an adjustment which sets an amount of pressure the heater applies to the eyelid meibomian glands.

52. An apparatus that provides regulated heat to at least one of a patient's eyelids, comprising:

a heater unit having a resistive heating element that produces heat that is transferred to the patient's eyelid when an electrical signal is applied thereto; and

a temperature regulator that applies the electrical signal to the heating elements in order to achieve heating of the heating elements to a specified temperature range.

53. The apparatus according toclaim 52, further comprising a thermal heat sink, coupled to a surface of the resistive heating element in order to transfer heat from the resistive heating element to the eyelid.

54. The apparatus according toclaim 52, further comprising an insulator coupled to a surface of the resistive heating element in order to reduce heat loss from the surface.

55. The apparatus according toclaim 52, further comprising goggles that are adjustably coupled to the heater unit in order to move the heater unit to achieve contact with the eyelid.

56. The apparatus according toclaim 52, further comprising a thermal heat sink, coupled to a surface of the resistive heating element in order to transfer heat from the heating element to the eyelid.

57. The apparatus according toclaim 52, further comprising an insulator coupled to a surface of the resistive heating element in order to reduce heat loss from a surface of the heating element.

58. The apparatus according toclaim 52, wherein the temperature regulator applies a pulse width modulated electrical signal to the resistive heating element in order to regulate the heat produced thereby.

59. The apparatus according toclaim 52, wherein the temperature regulator comprises a switch that selectively applies at least one of an electrical current and an electrical voltage to the resistive heating element in order to regulate the heat produced thereby.

60. The apparatus according toclaim 52, comprising a control processor and wherein the electrical signal is applied under control of the control processor.

61. The apparatus according toclaim 52, wherein the heater unit has a flexible portion that contacts the eyelid in order to conform to the eyelid.

62. The apparatus according toclaim 52, wherein the heater unit has a rigid portion that contacts the eyelid, and wherein the rigid portion is shaped to conform to the shape of the eyelid.

63. The apparatus according toclaim 52, further comprising an adhesive for attaching the heater unit directly to the eyelid.

64. The apparatus according toclaim 52, wherein the heater unit is attached to the eyelid by use of adhesive tape.

65. The apparatus according toclaim 52, further comprising a user interface that permits a user to establish at least one of a time and a temperature for the treatment.

66. The apparatus according toclaim 52, further comprising a vibration generator that generates vibration of the eyelid to stimulate secretion from the meibomian glands.

67. The apparatus according toclaim 52, further comprising goggles suitable for attaching to the patient's head and covering the eyelid of the patient with a lenspiece, and wherein the heater unit is moveably attached to the lenspiece.

68. The apparatus according toclaim 52, wherein the specified temperature range is greater than 37° C.

69. The apparatus according toclaim 52, wherein the specified temperature range comprises a approximately 44-47° C.

70. The apparatus according toclaim 53, further comprising a timer that shuts off the current to the heater element after a specified treatment time.

71. The apparatus according toclaim 70, wherein the specified treatment time is approximately 10 to 60 minutes.

72. The apparatus according toclaim 70, wherein the specified treatment time is approximately 15 minutes.

73. The apparatus according toclaim 52, further comprising a pressure sensor that measures a pressure with which the heater unit contacts the eyelid.

74. A method of treating at least one of a patient's eyelids with a regulated heat, comprising:

placing a heating unit having a heating element in contact with the patient's eyelid; and

applying a control signal to the heating element to generate heat at the heating element and transfer the generated heat to the eyelid for a prescribed time period.

75. The method according toclaim 74, further comprising, removing the control signal after expiration of the prescribed time period.

76. The method according toclaim 74, wherein the placing comprises:

installing goggles on the patient, the goggles having an adjustable eye interface containing the heating element; and

adjusting the eye interface to achieve contact with the eyelid.

77. The method according toclaim 74, wherein the placing comprises taping the eyepiece to the patient's eyelid using a strip of adhesive tape.

78. The method according toclaim 74 wherein the placing comprises attaching the eyepiece to the patient's eyelid using a double-sided medical adhesive tape.

79. The method according toclaim 74, wherein the attaching comprises attaching the eyepiece to the eyelid using an adhesive attachment.

80. The method according toclaim 74, wherein the heat is generated to greater than 37° Celsius.

81. The method according toclaim 74, further comprising applying vibration to the patient's eyelid.

82. The method according toclaim 74, wherein the prescribed time period is approximately 10 to 60 minutes.

83. The method according toclaim 74, applied to both upper and lower eyelids of the patient.

84. The method according toclaim 74, applied to at least one eyelid of two eyes of the patient.

85. The method according toclaim 74, further comprising measuring a pressure with which the heating unit contacts the eyelid.

86. The method according toclaim 74, wherein the heating element comprises a resistive heating element.

87. A computer readable storage medium storing instructions that, when executed on a programmed processor, carry out the method according toclaim 74.

88. A method of treating a mammalian eyelid, comprising heating the eyelid and maintaining a prescribed temperature for at least 4 minutes and no more than 60 minutes, while simultaneously applying mechanical energy and pressure to the eyelid.

89. A method of treating at least one mammalian eyelid, comprising applying continuous regulated heat to the at least one mammalian eyelid for a duration no longer than 60 minutes and applying a force to the eyelid during heating or within 3 minutes following heating for the purpose of clearing meibomian gland obstructions.

90. An apparatus for providing the controlled application of heat to the eyelid of a mammal comprising:

a heater unit having a means to produce heat in a specified temperature range;

an eyelid interfacing mechanism that couples the heater unit into contact with the eyelid; and

a means for adjusting the contact of the heater unit with the eyelid.

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