Patent Publication Number: US-8523928-B2

Title: System for inner eyelid heat and pressure treatment for treating meibomian gland dysfunction

Description:
RELATED APPLICATIONS 
     The present application is a continuation application of, and claims priority to, U.S. patent application Ser. No. 12/015,675, now U.S. Pat No. 8,128,673 entitled “System for Inner Eyelid Heat and Pressure Treatment for Treating Meibomian Gland Dysfunction,” filed on Jan. 17, 2008, which is a continuation-in-part patent application of the following U.S. applications: Ser. No. 11/434,033 entitled “Method and Apparatus for Treating Gland Dysfunction Employing Heated Medium,” filed on May 15, 2006; Ser. No. 11/434,446 entitled “Method and Apparatus for Treating Gland Dysfunction,” filed on May 15, 2006 now abandoned; Ser. No. 11/434,054, now U.S. Pat No. 8,083,787 entitled “Method and Apparatus for Treating Meibomian Gland Dysfunction,” filed on May 15, 2006; Ser. No. 11/541,291, now U.S. Pat No. 7,981,095 entitled “Method and Apparatus for Treating Meibomian Gland Dysfunction Employing Fluid Jet,” filed on Sep. 29, 2006; Ser. No. 11/541,418, now U.S. Pat No. 7,981,145 entitled “Treatment of Meibomian Glands,” filed on Sep. 29, 2006; Ser. No. 11/541,308 entitled “Melting Meibomian Gland Obstructions,” filed on Sep. 29, 2006; and Ser. No. 11/893,669 entitled “Meibomian Gland Illuminating and Imaging,” filed on Aug. 17, 2007; and which also claims priority to U.S. Provisional Patent Application No. 60/880,850 entitled “Method and Apparatus for Treating Meibomian Gland Obstructive Disease,” filed on Jan. 17, 2007, all of which are incorporated herein by reference in their entireties. 
    
    
     FIELD OF THE INVENTION 
     The field of the invention relates in general to treatment of mammalian eyes. More particularly, the present invention relates to treatment of meibomian gland dysfunction (MGD), which may be either responsible for or be a contributing factor to a patient suffering from a “dry eye” condition. A patient&#39;s meibomian glands are treated to aid in facilitating a sufficient protective lipid layer being generated and retained on the tear film of the eye to retain aqueous. 
     BACKGROUND OF THE INVENTION 
     In the human eye, the tear film covering the ocular surfaces is composed of three layers. The innermost layer in contact with the ocular surface is the mucus layer. The mucus layer is comprised of many mucins. The middle layer comprising the bulk of the tear film is the aqueous layer. The aqueous layer is important in that it provides a protective layer and lubrication to prevent dryness of the eye. Dryness of the eye can cause symptoms such as itchiness, burning, and irritation, which can result in discomfort. The outermost layer is comprised of many lipids known as “meibum” or “sebum.” This outermost lipid layer is very thin, typically less than 250 nm in thickness. The lipid layer provides a protective coating over the aqueous and mucus layers to limit the rate at which these underlying layers evaporate. A higher rate of evaporation of the aqueous layer can cause dryness of the eye. Thus, if the lipid layer is not sufficient to limit the rate of evaporation of the aqueous layer, dryness of the eye may result. The lipid layer also lubricates the eyelid during blinking, which prevents dry eye. Dryness of the eye is a recognized ocular disease, which is generally known as “dry eye.” If the lipid layer can be improved, the rate of evaporation is decreased, lubrication is improved, and partial or complete relief of the dry eye state is achieved. 
     The sebum that forms the outermost lipid layer is secreted by meibomian glands  10  of the eye, as illustrated in  FIGS. 1-3  of this application. The meibomian glands are enlarged, specialized sebaceous-type glands (hence, the use of “sebum” to describe the secretion) located on both the upper eyelid  12  and lower eyelid  14 . The meibomian glands contain orifices  16  that are designed to discharge lipid secretions onto the lid margins, thus forming the lipid layer of the tear film as the mammal blinks and spreads the lipid secretion. The typical human upper eyelid  12  has about twenty five (25) meibomian glands and the lower eyelid  14  has about twenty (20) meibomian glands, which are somewhat larger than those located in the upper lid. Each meibomian gland  10  has a straight long central duct  18  lined with four epithelial layers on the inner surface of the duct  18 . Along the length of the central duct  18  are multiple lateral out-pouching structures  20 , termed acini, where the secretion of the gland is manufactured. The inner lining of each acinus  20  differs from the main central duct  18  in that these specialized cells provide the secretions of the meibomian gland. The secretions flow from each acinus  20  to the duct  18 . 
     While it has not been established with certainty, there appears to be a valve system between each acinus  20  and the central duct  18  to retain the secretion until it is required, at which time it is discharged into the central duct  18 . The meibomian secretion is then stored in the central duct  18  and is released through the orifice of each gland onto the lid margin. Blinking and the squeezing action of the muscle of Riolan surrounding the meibomian glands  10  are thought to be the primary mechanism to open the orifice for the release of secretion from the meibomian gland  10 . Blinking causes the upper lid  12  to pull a sheet of the lipids secreted by the meibomian glands  10  over the other two layers of the tear film, thus forming a type of protective coating which limits the rate at which the underlying layers evaporate. Thus, a defective lipid layer or an insufficient quantity of such lipids can result in accelerated evaporation of the aqueous layer which, in turn, causes symptoms such as itchiness, burning, irritation, and dryness, which are collectively referred to as “dry eye.” 
     Various treatment modalities have been developed to treat the dry eye condition. These modalities include drops, which are intended to replicate and replace the natural aqueous tear film and pharmaceuticals which are intended to stimulate the tear producing cells. For example, eye drops such as Refresh Endura™, Soothe™, and Systane™ brand eye drops are designed to closely replicate the naturally occurring healthy tear film. However, their use and administration are merely a treatment of symptoms and not of the underlying cause. Further, the use of aqueous drops is generally for an indefinite length of time and consequently, extended use can become burdensome and costly. 
     Pharmaceutical modalities, such as the use of tetracycline, have also been suggested to treat meibomian gland dysfunction. One such treatment is disclosed in U.S. Patent Application Publication No. 2003/0114426 entitled “Method for Treating Meibomian Gland Disease,” U.S. Pat. No. 6,455,583 entitled “Method for Treating Meibomian Gland Disease” to Pflugfelder et al., and PCT Publication Application No. WO 99/58131 entitled “Use of Tetracyclines for Treating Meibomian Gland Disease.” However, this treatment has not proven to be universally clinically effective, and it may be unnecessary in cases where MGD is the result of obstruction of the gland without infection. 
     The use of corticosteroids has also been proposed to treat MGD as disclosed in U.S. Pat. No. 6,153,607 entitled “Non-preserved Topical Corticosteroid for Treatment of Dry Eye, filamentary Keratitis, and Delayed Tear Clearance (or Turnover)” to Pflugfelder et al. Again, this proposed treatment appears to treat the symptoms of dry eye, as opposed to treatment of the underlying cause. 
     Additionally, the use of topically applied androgens or androgen analogues has also been used to treat acute dry eye signs and symptoms in keratoconjuctivitis sicca. This is disclosed in U.S. Pat. Nos. 5,958,912 and 6,107,289, both entitled “Ocular Therapy in Keratoconjunctivitis Sicca Using Topically Applied Androgens or TGF-beta.” and both to Sullivan. 
     There is a correlation between the tear film lipid layer and dry eye disease. The various different medical conditions and damage to the eye and the relationship of the lipid layer to those conditions are reviewed in Sury Opthalmol 52:369-374, 2007. It is clear that the lipid layer condition has the greatest effect on dry eye disease when compared to the aqueous layer or other causes. Thus, while dry eye states have many etiologies, the inability of the meibomian gland  10  to sufficiently generate the lipid layer is a common cause of common dry eye state. This state is the condition known as “meibomian gland dysfunction” (MGD). MGD is a disorder where the meibomian glands  10  are obstructed or occluded.  FIG. 3  illustrates an example of such obstructions  22 ,  24  or occlusions  22 ,  24 . Plug obstructions  22  can occur in the orifice  16  of the central duct  18 . Alternatively, obstructions and occlusions  22 ,  24  can occur that block particular acinus  20 . The obstructions or occlusions  22 ,  24  can mean that the meibomian glands  10  are partially blocked or plugged, completely blocked or plugged, or any variation thereof. Obstructions and occlusions  22 ,  24  can be in a solid, semi-solid, or thickened, congealed secretion and/or a plug, leading to a compromise, or more specifically, a decrease in or cessation of secretion. Also, with a reduced or limited secretion, the meibomian gland  10  may be compromised by the occluded or obstructive condition often evidenced by a yellowish color, indicating a possible infection state. Alternatively, the meibomian gland  10  may be otherwise compromised so that the resulting protective lipid film is not adequate for preventing evaporation of the underlying layers on the eye. 
     MGD is frequently the result of keratotic obstructions, which partially or completely block the meibomian gland orifices  16  and/or the central duct (canal)  18  of the gland  10 , or possibly the acini or acini valves (assuming they do in fact exist) or the acini&#39;s junction  20  with the central duct  18 . Such obstructions  22 ,  24  compromise the secretory functions of the individual meibomian glands  10 . More particularly, these keratotic obstructions may be associated with or result in various combinations of bacteria, sebaceous ground substance, dead, and/or desquamated epithelial cells (see, Meibomian Gland Dysfunction and Contact Lens Intolerance, Journal of the Optometric Association, Vol. 51, No. 3, Korb et al., (1980), pp. 243-51). 
     Hormonal changes, which occur during menopause and particularly changing estrogen levels, can result in thickening of the oils secreted by the meibomian glands  10 . This may result in clogged gland orifices. Further, decreased estrogen levels may also enhance conditions under which staphylococcal bacteria can proliferate. This can cause migration of the bacteria into the glands  10  compromising glandular function and further contributing to occlusion, thus resulting in a decreased secretion rate of the meibomian gland  10 . 
     When the flow of secretions from the meibomian gland  10  is restricted due to the existence of an occlusion  22 ,  24 , cells on the eyelid margin have been observed to grow over the gland orifice  16 . This may further restrict sebum flow and exacerbate a dry eye condition. Additional factors may also cause or exacerbate meibomian gland dysfunction including age, disorders of blinking, activities such as computer use which compromise normal blinking, contact lens use, contact lens hygiene, cosmetic use, or other illness, particularly diabetes. It has been theorized that the acini  20  of the glands  10  may have valves at their junction with the main channel of the gland  10 . 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  20 . These obstructions or occlusions  22 ,  24  may have various compositions. 
     The state of an individual meibomian gland  10  can vary from optimal, where clear meibomian fluid is produced; to mild or moderate meibomian gland dysfunction where milky fluid or inspissated or creamy secretion is produced; to total blockage, where no secretion of any sort can be obtained (see “Increase in Tear Film Lipid Layer Thickness Following Treatment of Meibomian Gland Dysfunction,” Lacrimal Gland, Tear Film, and Dry Eye Syndromes,” Korb, et al., pp. 293-98, Edited by D. A. Sullivan, Plenum Press, New York (1994)). Significant chemical changes of the meibomian gland  10  secretions occur with meibomian gland dysfunction and consequently, the composition of the naturally occurring tear film is altered, which in turn, contributes to dry eye. 
     MGD may be difficult to diagnose, because visible indicators are not always present. For example, meibomitis, an inflammation of the meibomian glands  10 , can lead to MGD. Meibomitis may also be accompanied by blepharitis (inflammation of the lids). While meibomitis is obvious by inspection of the external lids, MGD may not be obvious even when examined with the magnification of the slit-lamp biomicroscope. This is because there may not be external signs or the external signs may be so minimal that they are overlooked. The external signs of MGD without obvious lid inflammation may be limited to subtle alterations of the meibomian gland orifices  16 , overgrowth of epithelium over the orifices  16 , and pouting of the orifices  16  of the glands  10  with congealed material acting as obstructions. In severe instances of MGD without obvious lid inflammation, the changes may be obvious, including serrated or undulated lid margins, orifice recession and more obvious overgrowth of epithelium over the orifices  16 , and pouting of the orifices  16 . 
     Thus to summarize, the meibomian glands  10  of mammalian (e.g., human) eyelids secrete oils that prevent evaporation of the tear film and provide lubrication to the eye and eyelids. These glands can become blocked or plugged (occluded) by various mechanisms leading to so-called “dry eye syndrome.” While not the only cause, MGD is a known cause of dry eye syndrome. The disorder is characterized by a blockage of some sort within the meibomian glands  10  or at their surface preventing normal lipid secretions from flowing from the meibomian glands  10  to form the lipid layer of the tear film. Such secretions serve to prevent evaporation of the aqueous tear film and lubricate the eye and eyelids  12 ,  14 , hence, their absence can cause dry eye syndrome. Obstructions or occlusions  22 ,  24  of the meibomian glands  10  may be present over or at the orifice  16  of the gland  10 , in the main channel  18  of the gland  10 , which may be narrowed or blocked, or possibly in other locations including the passages from the acini  20  to the main channel  18 . 
     While the present state of the art provides a number of treatments for dry eye, there is a need to treat the underlying cause, as opposed to the symptom. Many patients suffer from dry eye as a result of obstructions or occlusions in the meibomian glands. Thus, a need exists to provide effective treatment of the meibomian glands to restore a sufficient flow of sebum to the lipid layer of the eye to limit the rate of evaporation of the underlying layers. This includes loosening or removing possible obstructions or occlusions  22 ,  24  in the meibomian glands  10 .  FIG. 2  of the application shows the obstructions or occlusions  22 ,  24  of  FIG. 3  in the meibomian glands  10  removed to restore sebum flow to the lipid layer. 
     SUMMARY OF THE DETAILED DESCRIPTION 
     One embodiment of the present invention includes the breakthrough and previously unknown method of applying heat to the inner surface of the eyelid to treat dry eye caused by meibomian gland dysfunction (MGD). Applying heat to the inside of the eyelid can effectively and efficiently raise the temperature at the meibomian glands to a temperature sufficient to melt, loosen, or soften more serious occlusions or obstructions in the meibomian glands. The occlusions or obstructions can then be physically expressed to improve sebum flow from the meibomian glands to reduce evaporation of the aqueous layer. 
     Some patients have obstructions or occlusions in their meibomian glands that will not sufficiently melt, loosen, or soften to be expressed without attaining heightened temperatures at the meibomian glands. In many instances, these temperatures either cannot be achieved when applying heat to the outside of the eyelid, or these temperatures may be achievable, but only after applying heat to the outside of the eyelid for a significant period of time. Heightened temperatures may also only be achieved by applying heat at unsafe temperatures that would either produce an unacceptable pain response to the patient or damage to the patient&#39;s eyelid. This is because of the temperature drop between the outside of the eyelid and the meibomian glands due to conductive heat loss. Heat applied to the outside of the eyelid must conductively travel through the eyelid tissue and through the tarsal plate that encases the meibomian glands inside the eyelid. As an example, it may take twenty to thirty minutes for the temperature at the meibomian glands to reach only a temperature of 41 to 42 degrees Celsius when applying heat to the outside of the eyelid that will not burn or damage the patient&#39;s eyelid or surrounding tissue. Temperatures may need to reach between 43 to 45 degrees Celsius, for example, for melting, loosening, or softening of certain obstructions or occlusions in a patient&#39;s meibomian glands. 
     Until the present application, it was only known to apply heat to the outside of the eyelid to treat meibomian gland dysfunction (MGD). Medical professionals would have thought it counterintuitive to apply heat to the inside of the eyelid. It was thought that applying heat to the inside of the eyelid would risk damage to the eyelid or the eyeball itself. Previous studies of heat application to skin showed that damage could occur for temperatures at or above 45 degrees Celsius. These studies were conducted on external keratinized skin. The tissue on the inner eyelids is non-keratinized epithelium, and as such, is not as well protected from heat as keratinized skin. Thus, one would naturally believe that applying heat to the inside of the eyelid would produce a pain response at lower temperatures than on the outer eyelid surface. However, it has been surprisingly discovered that applying heat to the inside of the eyelid is not only safe, but effective at dislodging obstructions and/or occlusions in the meibomian glands as part of a MGD treatment. 
     It was hypothesized that heating the inside of the eyelid may provide a more efficient conductive heat transfer to the meibomian glands. Attaining a more efficient heat transfer may allow higher temperatures to be attained at the meibomian glands and/or in a more efficient time to melt, loosen, or soften more serious obstructions or occlusions in the meibomian glands. Heat conduction increases with thinner tissue. The meibomian glands are located closer to the inside surface of the eyelid than the outside surface of the eyelid. Further, there is no tarsal plate located between the inside of the eyelid and the meibomian glands. Thus, it was discovered than conductive heat transfer to the meibomian glands is more efficient when heating the inside of the eyelid. 
     In this regard, an experiment was carried out where heat was applied to the inside of the eyelid (and more particularly the palpebral conjunctiva) against traditional notions and known principles. It was discovered that heat could be applied to the inside of the eyelid without damaging the patient&#39;s eye if temperature is regulated. For example, it was determined that most patients can tolerate a surface temperature of 43-44.5 degrees Celsius without anesthesia and without significant pain. It was found that some patients could tolerate temperatures over 44.5 degrees Celsius without anesthesia. Further, it was discovered that heightened temperatures at the meibomian glands could be attained and in less time when applying heat to the inside of the eyelid than to the outside of the eyelid due to more effective conductive heat transfer and the proximity of the heating to the eyelid surface. 
     While not limiting to the present invention, the ability to effectively and more efficiently raise the temperature at the meibomian glands by applying heat to the inside or inner surface of the eyelid may prove instrumental in reaching the melting, loosening, or softening points of obstructions or occlusions. Applying heat to the inside of the eyelid can also include applying heat to the meibomian glands orifices that are located at the inner surface of the eyelid at the lid margin. The orifices may also be obstructed or occluded. The application of heat to the inside of the eyelid and proximate or directly to the meibomian glands orifices may also prove instrumental in restoring sufficient sebum flow for the lipid layer. When the term or phrase applying heat to the “inside” or “inner surface” of the eyelid is referenced in this application, such also encompasses the application of heat to the meibomian glands orifices. 
     The application of heat may be regulated, meaning that a heating means or element is controlled to be within the temperatures and means that are safe for the inner surface of the eyelid and at a sufficient temperature for melting, loosening, or softening an occlusion or obstruction in the meibomian gland. The heat is maintained for a period of time sufficient to melt, loosen, or soften the occlusions or obstructions. Either during heat application or after heat application is removed, the occlusions or obstructions in the meibomian glands are expressed to remove obstructions or occlusions thus providing an improved pathway to restore or improve sebum flow from the gland. 
     In one embodiment, increasing the temperature of the surface of the palpebral conjunctiva to at least 37 degrees Celsius can begin to provide therapeutic effect for milder cases of MGD. A therapeutic temperature can be any temperature above body temperature. One preferred range for treatment is 43 to 45 degrees Celsius, with a target of 43 to 44.5 degrees Celsius. A time range to apply heat may be a period between 1-10 minutes, and may be limited to a range of 3-6 minutes. Temperature in this range has been found effective and comfortable to the patient when treating MGD. 
     In one embodiment, the application of heat may be regulated. Regulated heat can include controlling heat according to a temperature profile. The temperature profile may be a constant temperature, include ramp-ups, ramp-downs, peaks and valleys. Further, the temperature profile may include heat pulses or be modulated with various characteristics, including the use of on/off switching or pulse width modulation (PWM) techniques for example. The use of modulated heat may allow the temperature to be raised even higher at the eyelid without damages to the patient&#39;s eyelid since the increased temperatures are applied for shorter periods of time. Obstructions or occlusions in the meibomian glands may have melting, loosening, or softening points that are beyond temperatures that may be applied without the use of modulated heat. The temperature needed to melt, loosen, or soften obstructions or occlusions may depend on how keratinized the obstruction or occlusion is. Not all obstructions or occlusions have the same melting, loosening, or softening points. 
     By example only, elevated temperatures between 45 and 55 degrees Celsius may be possible when applying regulated heat, especially if the eyelid has been anesthetized. However, heat should always be applied to the eyelid at temperatures that take into consideration the pain response of the patient as well as whether damage will occur to the patient&#39;s eyelid and/or surrounding tissues. Depending on the severity of the patient&#39;s MGD or the patient&#39;s pain tolerance, elevated temperatures may be used with patients on an individualized basis when applying heat. It has been found that lighter skinned patients can generally tolerate less heat than darker skinned patients, and darker skinned patients tend to exhibit less inflammation as a result of exposure to the heat. Other factors, including humidity, may contribute to a patient&#39;s tolerance of greater temperatures. For example, humans can generally tolerate heat up to 70 to 80 degrees Celsius in dry saunas where humidity is low. Application of heat in higher humidity environments may cause pain and/or burns to occur at lower temperatures. 
     Severe cases of MGD that cause substantial irritation or risk to the patient may call for temperatures that would produce category one or two burns to the patient&#39;s eyelid, since these burns generally heal. Temperatures that cause category three burns should be avoided. In summary, treatment times and/or temperature can be adjusted to account for these differences. The present invention is not limited to any particular temperature or time ranges as long as therapeutic temperature is being applied to the meibomian glands. 
     The regulated heat can be maintained at a therapeutic temperature for a treatment period. The treatment period can be approximately 1 to 10 minutes for example. The heat could also be repeatedly applied and maintained for a desired period of time to keep the occlusion or obstruction in a melted, loosened, or softened state. Either during or after such treatment by regulated heat, mechanical expression of lipids and other fluids from the meibomian glands has been found to clear obstructions which have essentially melted or been placed in a suspension state (by virtue of melting materials binding solids together). 
     In one embodiment, after expression of the occlusions or obstructions is performed, an optional pharmacological agent may be applied to the meibomian gland to promote the free flow of sebum and/or reduce or prevent inflammation or infections of the eye or eyelids. Many pharmacological agents have been proposed for treatment of dry eye syndrome, any of which may be effective or more effective upon clearing of obstructions within the meibomian glands. Some of the pharmacological agents that may be utilized include, but are not limited to: antibiotics such as topical or oral tetracycline and chemically modified tetracycline, testosterone, topical or oral corticosteroids, topical androgens or androgen analogues, omega 3 fatty acid compounds such as fish oils, Laennec, enzymes that promote lipid production, agents that stimulate production of enzymes that promote lipid production, and/or any agent which acts as a secretagogue to enhance meibomian gland secretion or secretion of other tear components. For example, androgen and androgen analogues and TGF-beta have been reported to act as a secretagogue to enhance meibomian gland secretion. 
     These compounds are illustrative examples of appropriate pharmacological agents, but those skilled in the art will appreciate that other pharmacological compounds may be utilized. 
     Also, agents, such as Restasis (cyclosporine A), that replace or promote production of the tear component may also be applied more effectively after treating the meibomian glands according to the present invention. Treating the meibomian glands improves the lipid layer thus reducing evaporation and conserving the aqueous layer. Conservation of the aqueous layer reduces the need for tear substitutes to be applied through tear component agents. Thus, tear component agents may not have to be used as often when employing the present invention to treat a patient&#39;s MGD. 
     In the course of experimenting with the application of heat to the inside of the eyelid, it was also discovered that convective heat losses occur due to blood flow in the blood vessels located inside the eyelid. Blood flow through blood vessels located inside the eyelid produces convective heat losses. The blood flow serves as a natural “heat sink” provided by the body. Convective heat loss is lessened when applying heat to the inside of the eyelid than when applying heat to the outside of the eyelid. This is because fewer blood vessels are located between the meibomian glands and the inside of the eyelid than the outside of the eyelid. The meibomian glands are located closer to the inside of the eyelid. However, convective heat loss still occurs when heating the inside of the eyelid. However, it was discovered that if the blood flow was reduced, convective heat losses could be minimized allowing for temperatures to be attained and sustained at the meibomian glands in an even more efficient manner and in less time. 
     Thus, one embodiment of the present invention also includes the further application of force to the patient&#39;s eyelid in addition to heat. The application of force can further assist in obtaining higher temperatures more efficiently inside the eyelid at the palpebral conjunctiva and at the meibomian gland in a shorter period of time and thus more efficiently. This is because the application of force may reduce blood flow to the eyelid to reduce convective heat loss, as discussed above. 
     Applying force can also result in a more efficient conductive heat transfer from an applied heat source, because the pressure created by the force causes the heat source to be compressed against the tissue of the eyelid. This compression can have several benefits. Compression spreads out the tissue to which heating is applied thus making it thinner and improving conductive heat transfer. Compression can also “squeeze out” air pockets at the surface of the eyelid due to the microscopic roughness of skin. Thus, compression of the heat source against the eyelid increases the surface contact between the heat source and the surface of the eyelid (which increases the heat transfer equation) to provide a more effective conductive heat transfer to the meibomian glands. This results in the meibomian glands being heated to the desired temperature level in a shorter period of time due to these gained efficiencies. Further, increased temperatures may be attained that may not have otherwise been obtained, or obtained using less heat or thermal energy. Because the heating is located in close proximity to the eyelid surface and heating is further compressed against the eyelid surface, heat transfer is very efficient providing for the temperature at the surface of the eyelid to be very close to the temperature at the meiboimian glands. 
     The applied force may be regulated, meaning that a force generating means is controlled to be within pressure ranges that are safe to be applied to the eyelid and at sufficient pressure to allow the temperature at the meibomian gland to be raised sufficiently. The force can also be a constant force and be provided manually. The force may be applied during heating, after heating, or both during and after heating. In either case, the force may assist in expressing occlusions or obstructions when in a loosened, softened, or melted state from the meibomian glands. The force may include vibratory type forces, including those generated mechanically or those using fluid type devices or mechanisms. The level of force needed to express obstructions or occlusions in the glands may be greatly reduced when heat is applied to the obstructions or occlusions to place them in a melted, softened, or loosened state. 
     The application of force can also stimulate the movement of fluids or suspensions of occlusions or obstructions from the glands. The present invention can be used with devices, which generally apply a regulated force or milking action to the eyelid to express the fluids or suspensions or to otherwise mechanically stimulate the movement of fluids from the glands. In some instances, a small, gentle, continuous force applied to the eyelid will assist in expression of the fluids and suspensions. Vibration can also be used when applying force simultaneously or immediately after the heating to further assist in the expression. 
     Any apparatus, device, or tool can be used to apply heat and/or force to the eyelids to treat MGD. In one embodiment, a force can be applied to the outside of the eyelid while heat is applied to the inside of the eyelid to treat MGD. The heating of the inner surface of the upper or lower eyelid can be done by any convenient method. The lids can be heated one at a time or both at once, depending on the time available to remove the occlusions once heated and the device or method to heat being employed is removed. Several heat and force application devices are disclosed. 
     One device for heating the palpebral conjunctiva is disclosed in U.S. Provisional Patent Application Ser. No. 60/880,850, previously referenced above and to which the present application claims priority. In this application, a lid warmer containing a heating element is placed in-between the eyeball and against the palpebral conjunctiva. The heating element is energized or powered to generate a heat to the inside of the eyelids when the lens in placed on the eyeball. The lid warmer may also contain an integrated insulator that prevents substantial heat from reaching the eyeball and thus protects the cornea and sclera. The heating element may be biased according to its location in the lid warmer, and in particular to be located behind the insulator proximate the eyelid, to produce more heat on the insides of the eyelid than on the eyeball. The lid warmer may also contain a platform. The platform provides a handle for insertion or adjustment of the heating element, and an area to encapsulate heating components, including an electrical interface to allow an attached heating controller to generate an electrical signal to the heating element to produce a regulated heat to the inside of the eyelid. 
     The lid warmer may also be used in conjunction with a device that generates a regulated force to the outside of the eyelid when heat is applied to the inside of the eyelid. In one embodiment, an eyecup having an inflatable bladder is placed on the outside of the eyelid while the lens is sitting on the eyeball. The eyecup may include an interface that allows the eyecup to be placed onto the platform extending from the lid warmer. In this manner, when the eyecup is engaged onto the platform and the bladder is inflated, a regulated force is applied to the outside of the eyelid, thus compressing the eyelid against the lid warmer at the inside of the eyelid. Thus, the meibomian glands are “sandwiched” between, meaning surrounded by, the eyecup and the lid warmer, wherein the eyecup applies a force vector towards the lid warmer to create a pressure on the eyelid and at the meibomian glands within the eyelid. This assists in loosening obstructions or occlusions in the meibomian glands as well as reduces blood flow in the eyelids to prevent convective heat loss of the heat generated by the lid warmer. 
     Alternatively, a membrane could be attached to the eyecup and employed to generate force. The membrane could be made of different materials and materials that stretch, and are resilient. Several embodiments are disclosed involving a lid warmer and eyecup to be used to apply heat and force to the eyelid as part of treating MGD. The present invention is not limited to any particular type of lid warmer and/or force generating apparatus or device. 
     In another embodiment, force and heat can be applied to tissue proximate the meibomian glands to treat MGD. As discussed above, the application of force can further assist in obtaining higher temperatures at the meibomian glands and in a shorter period of time and thus more efficiently. The application of force can improve conductive heat transfer efficiency and/or reduce convective heat loss. Any apparatus, device, or tool can be used to apply heat and force to the tissue proximate the meibomian glands. The application of force may also allow heat to be maintained for a longer period of time. This is because the application of force may reduce blood flow to the eyelid, thus reducing convective heat loss and increasing conductive heat transfer into the eyelid and to the glands. The heat and/or force applied to the tissue can be regulated, as discussed above. The force may be applied during heating, after heating, or both during and after heating. The force can remain after the heat is removed, thus increasing the time before the body&#39;s heat sink effect returns the eyelid to normal temperature. The application of force may also assist in expressing the occlusions or obstructions when in a loosened, softened, or melted state from the meibomian glands. 
     In another embodiment, force can be applied to the inside of the eyelid and heat applied to the outside of the eyelid to treat MGD. As discussed above, the application of force can further assist in obtaining higher temperatures at the meibomian gland and in a shorter period of time and thus more efficiently. The application of force can to improve conductive heat transfer efficiency and/or reduce convective heat loss. Any apparatus, device, or tool can be used to apply heat and force to the outside of the eyelid. The application of force may also allow heat to be maintained on the outside of the eyelid for a longer period of time. This is because the application of force may reduce blood flow to the eyelid, thus reducing convective heat loss and increasing conductive heat transfer into the eyelid and to the glands. The heat applied to the outside of the eyelid and/or the force applied to the inside of the eyelid can be regulated, as discussed above. The force may be applied during heating, after heating, or both during and after heating. The force can remain after the heat is removed, thus increasing the time before the body&#39;s heat sink effect returns the eyelid to normal temperature. The application of force may also assist in expressing the occlusions or obstructions when in a loosened, softened, or melted state from the meibomian glands. 
     In another embodiment, force and heat can both be applied to the outside of the eyelid to treat MGD. As discussed above, the application of force can further assist in obtaining higher temperatures at the meibomian gland and in a shorter period of time and thus more efficiently. The application of force can improve conductive heat transfer efficiency and/or reduce convective heat loss. Any apparatus, device, or tool can be used to apply heat and force to the outside of the eyelid. The application of force may also allow heat to be maintained on the outside of the eyelid for a longer period of time. This is because the application of force may reduce blood flow to the eyelid, thus reducing convective heat loss and increasing conductive heat transfer into the eyelid and to the glands. The heat and/or force applied to the outside of the eyelid can be regulated, as discussed above. The force may be applied during heating, after heating, or both during and after heating. The force can remain after the heat is removed, thus increasing the time before the body&#39;s heat sink effect returns the eyelid to normal temperature. The application of force may also assist in expressing the occlusions or obstructions when in a loosened, softened, or melted state from the meibomian glands. 
     In yet another embodiment, heat can be applied to both the inside and outside of the eyelid to treat MGD. Force can also be applied to the eyelid. As discussed above, the application of force can further assist in obtaining higher temperatures at the meibomian gland and in a shorter period of time and thus more efficiently. The application of force can improve conductive heat transfer efficiency and/or reduce convective heat loss. Any apparatus, device, or tool can be used to apply heat and force to the outside of the eyelid. The application of force may also allow heat to be maintained on the outside of the eyelid for a longer period of time. This is because the application of force may reduce blood flow to the eyelid, thus reducing convective heat loss and increasing conductive heat transfer into the eyelid and to the glands. The heat and/or force applied to the outside of the eyelid can be regulated, as discussed above. The force may be applied during heating, after heating, or both during and after heating. The force can remain after the heat is removed, thus increasing the time before the body&#39;s heat sink effect returns the eyelid to normal temperature. The application of force may also assist in expressing the occlusions or obstructions. 
     Those skilled in the art will appreciate the scope of the present invention and realize additional aspects thereof after reading the following detailed description of the preferred embodiments in association with the accompanying drawing figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the invention, and together with the description serve to explain the principles of the invention. 
         FIG. 1  illustrates an exemplary upper and lower human eyelid showing the meibomian glands; 
         FIG. 2  illustrates an exemplary cutaway view of a meibomian gland; 
         FIG. 3  illustrates an exemplary cutaway view of a meibomian gland having several clogging mechanisms; 
         FIG. 4  illustrates an exemplary eyelid temperature profile of an inner and outer eyelid temperature versus time when heat is applied to the exterior of the eyelid; 
         FIG. 5  illustrates an exemplary eyelid lid temperature profile of inside and outside eyelid temperature versus time when heat is applied to the inside the eyelid; 
         FIG. 6  is a flowchart illustrating an exemplary process of applying heat to the inner eyelid relating to treating meibomian glands; 
         FIG. 7  illustrates an exemplary lid temperature profile of eyelid temperature versus time when heat and force is applied to inside the eyelid; 
         FIG. 8  is a flowchart illustrating an exemplary process of applying heat to the inner eyelid with the addition of force applied to the outside or outer surface of the eyelid relating to treating the meibomian glands; 
         FIG. 9  illustrates a heat and force application device according to one embodiment relating to the present invention to facilitate the application of heat to the inside and force to the outside of a patient&#39;s eyelid relating to treating meibomian glands; 
         FIG. 10  illustrates a lid warmer component of the heat and force application device illustrated in  FIG. 9 , which is adapted to fit onto a patient&#39;s eye to controllably deliver heat to the inside of the patient&#39;s eyelid, according to one embodiment relating to the present invention; 
         FIG. 11  illustrates the process of placing the lid warmer on the patient&#39;s eye inside the eyelid to install the heat application device onto a patient&#39;s eye for treating the meibomian glands, according to one embodiment relating to the present invention; 
         FIG. 12  illustrates a cross-sectional view of the lid warmer illustrated in  FIGS. 9-11  to further illustrate heat delivery components and features of the lid warmer, according to one embodiment relating to the present invention; 
         FIGS. 13A and 13B  illustrate embodiments of a lid warmer and eyecup heat and force application device for securing the eyecup to the lid warmer as part of installing the force application device onto a patient&#39;s eye for treating the meibomian glands; 
         FIG. 14  illustrates an interface adapted to be attached between the eyecup and the controller of  FIGS. 9-13B  for facilitating selective and controllable communication of heat and/or force to the eyelid, according to one embodiment of the present invention; 
         FIG. 15  illustrates a top level system diagram of the temperature and pressure control and communication components of the heat and force application device for selectively and controllably communicating to the lid warmer and eyecup components to apply heat to the inside of a patient&#39;s eyelid and/or force to the outside of the patient&#39;s eyelid, according to one embodiment relating to the present invention; 
         FIG. 16  illustrates an interface circuit diagram for the heating and force application device, according to one embodiment relating to the present invention; 
         FIG. 17  illustrates a pressure control system for the heating and force application device to selectively and controllably apply force to the outside of a patient&#39;s eyelid, according to one embodiment relating to the present invention; 
         FIG. 18  illustrates a temperature control system for the heating and force application device to selectively and controllably apply heat to the inside of a patient&#39;s eyelid, according to one embodiment relating to the present invention; 
         FIG. 19  is a flowchart illustrating the basic process employed by the heat and force application device to selectively and controllably apply heat to the inside of a patient&#39;s eyelid and/or force to the outside of the patient&#39;s eyelid, according to one embodiment relating to the present invention; 
         FIG. 20  illustrates a system state flow diagram for the heating and force application device, according to one embodiment relating to the present invention; 
         FIGS. 21A and 21B  illustrate the “Reset” state flow diagram according to the system state flow diagram of  FIG. 20 , according to one embodiment relating to the present invention; 
         FIG. 22  illustrates the optional “Fuseblow” state flow diagram according to the system state flow diagram of  FIG. 20 , according to one embodiment relating to the present invention; 
         FIG. 23  illustrates the “Run” state flow diagram according to the system state flow diagram of  FIG. 20 , according to one embodiment relating to the present invention; 
         FIG. 24  illustrates the “Pause” state flow diagram according to the system state flow diagram of  FIG. 20 , according to one embodiment relating to the present invention; 
         FIGS. 25A and 25B  illustrate the “Monitor” state flow diagram according to the system state flow diagram of  FIG. 20 , according to one embodiment relating to the present invention; 
         FIG. 26  illustrates the “Stop” state flow diagram according to the system state flow diagram of  FIG. 20 , according to one embodiment relating to the present invention; 
         FIG. 27  illustrates an exploded perspective view of an alternative heat and force application device for treating MGD, according to one embodiment relating to the present invention; 
         FIG. 28  is an illustration of the alternative heat and force application device according to a cross section taken along line A-A in  FIG. 27 , according to one embodiment relating to the present invention; 
         FIG. 29  illustrates an exploded view of the alternative heat and force application device according to  FIG. 27 , according to one embodiment relating to the present invention; 
         FIG. 30  illustrates a sectional view of the alternative heat and force application device according to  FIG. 27 , according to one embodiment relating to the present invention; 
         FIGS. 31A and 3B  are illustrations of another alternative heat and force application device, according to one embodiment of the present invention; 
         FIG. 32  is an illustration of another alternative heat and force application device, according to one embodiment of the present invention; 
         FIG. 33  is an illustration of another alternative heat and force application device, according to one embodiment of the present invention; 
         FIG. 34  is an illustration of another alternative heat and force application device, according to one embodiment of the present invention; 
         FIG. 35  is an illustration of another alternative heat and force application device, according to one embodiment of the present invention; 
         FIGS. 36A and 36B  are illustrations of another alternative heat and force application device, according to one embodiment of the present invention; 
         FIG. 37  is an illustration of another alternative heat and force application device, according to one embodiment of the present invention; 
         FIGS. 38A and 38B  are illustrations of another alternative heat and force application device, according to one embodiment of the present invention; 
         FIG. 39  is an illustration of another alternative heat and force application device, according to one embodiment of the present invention; 
         FIG. 40  is an illustration of another alternative heat and force application device, according to one embodiment of the present invention; 
         FIG. 41  is a flowchart illustrating an alternative meibomian gland treatment employing applying heat and force to tissue proximate the meibomian gland to reduce heat loss when heat is applied to melt, loosen, or soften obstructions or occlusions; 
         FIG. 42  is a flowchart illustrating an alternate meibomian gland treatment employing applying heat to the outside of a patient&#39;s eyelid and force to the inside of the patient&#39;s eyelid for treating meibomian glands; 
         FIG. 43  is a flowchart illustrating an alternate meibomian gland treatment employing applying heat and force to the outside of a patient&#39;s eyelid for treating meibomian glands; and 
         FIG. 44  is a flowchart illustrating an alternate meibomian gland treatment employing applying heat to both the inside and the outside of a patient&#39;s eyelid for treating meibomian glands. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the invention and illustrate the best mode of practicing the invention. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the invention and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims. 
     One embodiment of the present invention includes the breakthrough and previously unknown method of applying heat to the inner surface of the eyelid to treat dry eye caused by meibomian gland dysfunction (MGD). Applying heat to the inside of the eyelid can effectively and efficiently raise the temperature at the meibomian glands to a temperature sufficient to melt, loosen, or soften more serious occlusions or obstructions in the meibomian glands. The occlusions or obstructions can then be physically expressed to improve sebum flow from the meibomian glands to reduce evaporation of the aqueous layer. 
     Some patients have obstructions or occlusions in their meibomian glands that will not sufficiently melt, loosen, or soften to be expressed without attaining heightened temperatures at the meibomian glands. In many instances, these temperatures either cannot be achieved when applying heat to the outside of the eyelid, or these temperatures may be achievable, but only after applying heat to the outside of the eyelid for a significant period of time. Heightened temperatures may only be achieved by applying heat at unsafe temperatures that would either produce an unacceptable pain response to the patient or damage to the patient&#39;s eyelid. This is because of the temperature drop between the outside of the eyelid and the meibomian glands due to conductive heat loss. Heat applied to the outside of the eyelid must conductively travel through the eyelid tissue and through the tarsal plate that encases the meibomian glands inside the eyelid. As an example, it may take twenty to thirty minutes for the temperature at the meibomian glands to reach only a temperature of 41 to 42 degrees Celsius when applying heat to the outside of the eyelid that will not burn or damage the patient&#39;s eyelid or surrounding tissue. Temperatures may need to reach between 43 to 45 degrees Celsius, for example, for melting, loosening, or softening of certain obstructions or occlusions in a patient&#39;s meibomian glands. 
     Until the present application, it was only known to apply heat to the outside of the eyelid to treat meibomian gland dysfunction (MGD). Medical professionals would have thought it counterintuitive to apply heat to the inside of the eyelid. It was thought that applying heat to the inside of the eyelid would risk damage to the eyelid or the eyeball itself. Previous studies of heat application to skin showed that damage could occur for temperatures at or above 45 degrees Celsius. These studies were made on external keratinized skin. The tissue on the inner eyelids is non-keratinized epithelium, and as such, is not as well protected from heat as keratinized skin. Thus, one would naturally believe that applying heat to the inside of the eyelid would produce a pain response at lower temperatures than on the outer eyelid surface. However, it has been surprisingly discovered that applying heat to the inside of the eyelid is not only safe, but effective at dislodging obstructions and/or occlusions in the meibomian glands as part of a MGD treatment. 
     It was hypothesized that heating the inside of the eyelids may provide a more efficient conductive heat transfer to the meibomian glands. Attaining a more efficient heat transfer may allow higher temperatures to be attained at the meibomian glands and in a more efficient time to melt, loosen, or soften more serious obstructions or occlusions in the meibomian glands. The meibomian glands are located closer to the inside surface of the eyelid than the outside surface of the eyelid. Further, there is no tarsal plate located between the inside of the eyelid and the meibomian glands. Thus, it was discovered than conductive heat transfer to the meibomian glands is more efficient when heating the inside of the eyelid. Heat conduction increases with thinner tissue. 
     In this regard, an experiment was carried out where heat was applied to the inside of the eyelid (and more particularly the palpebral conjunctiva) against traditional notions and known principles. It was discovered that heat could be applied to the inside of the eyelid without damaging the patient&#39;s eye if regulated. For example, it was determined that most patients can tolerate a surface temperature of 43-44.5 degrees Celsius without anesthesia and without significant pain. It was found that some patients could tolerate temperatures over 44.5 degrees Celsius without anesthesia. Further, it was discovered than heightened temperatures could be attained and in less time when applying heat to the inside of the eyelid than to the outside of the eyelid due to more effective conductive heat transfer and the proximity to the heating device. 
     An exemplary lid temperature profile  32  that may be generated when heat is applied to the inside of the eyelid is illustrated in  FIG. 5 . There, a graph depicts what the temperature of the inner surface of an eyelid may be as a function of time when a source of constant heat is applied to an example subject patient. A heat source attached to the inside of the patient&#39;s eyelid is turned on for a period of time. For this patient, it took approximately 30 seconds for the eyelid&#39;s inner surface to reach about 44 degrees Celsius. Unlike the lid temperature profile illustrated in  FIG. 4 , the inner surface of the patient&#39;s eyelid did reach a higher temperature when heat was applied to the inside of the eyelid. For example, it may only take two to three minutes to bring the temperature at the meibomian glands to 43-45 degrees Celsius or higher when applying heat to the inside of the eyelid. While not limiting to the present invention, the ability to raise the temperature at the meibomian glands may prove instrumental in melting, loosening, or softening obstructions or occlusions in the meibomian gland to reach the loosening, softening, or melting point of the obstruction or occlusion. 
     In this regard, an embodiment of the present invention to apply heat to the inside or inner surface of the eyelid proximate the meibomian glands to treat MGD in basic form is illustrated in the flowchart of  FIG. 6 . This has the advantage in that it typically takes less time to raise the temperature at the meibomian glands sufficient to melt, loosen, or soften an obstruction or occlusion than if heat were applied directly to the outside of the eyelid. Further, heating the inside of the eyelid may allow higher temperatures to be achieved than if the outside of the eyelid were heated. 
     First, heat is applied to the inner surface of the eyelid to a temperature adequate to melt, loosen, or soften obstructions or occlusions in the meibomian glands (step  40 ). For example, heat may be applied to raise the temperature at the inside of the eyelid to 43-47 degrees Celsius, although the present invention is not limited to this temperature range. A time range to apply heat may be a period between 1-10 minutes, and may be limited to a range of 3-6 minutes. The heat may be regulated meaning that a heating means or element is controlled to be within the temperatures and means that are safe for the inner surface of the eyelid and at a sufficient temperature for melting, loosening, or softening an occlusion or obstruction in the meibomian gland. By sufficient temperature, this refers to the amount of heating needed to heat the palpebral conjunctiva to achieve the desired melting, loosening, or softening of the obstruction. The heat may be maintained for a period of time until the temperature reaches the desired level sufficient to melt, loosen, or soften the obstructions or occlusions (step  42 ). For example, the heat may be applied for 1 to 10 minutes, although the present invention is not limited to any particular amount of heat application time. Thereafter, either during heating or after, obstructions or occlusions in the meibomian glands may be expressed so that sebum flow is restored from the glands to establish a sufficient lipid layer (step  44 ). 
     While not limiting to the present invention, the ability to effectively and more efficiently raise the temperature at the meibomian glands may prove instrumental in melting, loosening, or softening obstructions or occlusions in the meibomian gland to reach the loosening or melting point of the obstruction or occlusion. 
     As used herein, the terms “melt,” “loosen,” and “soften” and variants thereof are to be interpreted broadly. These terms broadly encompass any change in form or state of the obstructive or occluding material causing or contributing to an obstruction or occlusion related to a disorder of the eye or eyelid structure to a form such that the obstruction or occlusion can be more easily freed or expressed. This includes, but is not limited to, changing form from less of a solid form or state to more of a liquefied form or state, including but not limited to dissolving, loosening, liquefying, and/or softening of the obstructive or occluding material to be removed, and/or dissolving, loosening, liquefying, or softening of material that holds together particulate matters causing or contributing towards the obstruction or occlusion related to a disorder of the eye or eyelid structure and other modalities. 
     The application of heat may be regulated, meaning that a heating means or element is controlled to be within the temperatures and means that are safe for the inner surface of the eyelid and at a sufficient temperature for melting, loosening, or softening an occlusion or obstruction in the meibomian gland. The heat is maintained for a period of time sufficient to melt, loosen, or soften the occlusions or obstructions. Either during heat application or after heat application is removed, the occlusions or obstructions in the meibomian glands are expressed to remove obstructions or occlusions thus providing an improved pathway to restore or improve sebum flow from the gland. 
     In one embodiment, increasing the temperature of the surface of the palpebral conjunctiva to at least 37 degrees Celsius can begin to provide therapeutic effect for milder cases of MGD. A therapeutic temperature can be any temperature above body temperature. One preferred range for treatment is 43 to 45 degrees Celsius, with a target of 43 to 44.5 degrees Celsius. A time range to apply heat may be a period between 1-10 minutes, and may be limited to a range of 3-6 minutes. Temperature in this range has been found effective and comfortable to the patient when treating MGD. 
     In one embodiment, the application of heat may be regulated. Regulated heat can include controlling heat according to a temperature profile. The temperature profile may be a constant temperature, include ramp-ups, ramp-downs, peaks and valleys. Further, the temperature profile may include heat pulses or be modulated with various characteristics, including the use of on/off switching or pulse width modulation (PWM) techniques for example. The use of modulated heat may allow the temperature to be raised even higher at the eyelid without damages to the patient&#39;s eyelid since the increased temperatures are applied for shorter periods of time. Obstructions or occlusions in the meibomian glands may have melting, loosening, or softening points that are beyond temperatures that may be applied without the use of modulated heat. The temperature needed to melt, loosen, or soften obstructions or occlusions may depend on how keratinized the obstruction or occlusion is. Not all obstructions or occlusions have the same melting, loosening, or softening points. 
     By example only, elevated temperatures between 45 and 55 degrees Celsius may be possible when applying regulated heat, especially if the eyelid has been anesthetized. However, heat must always be applied to the eyelid at temperatures that take into consideration the pain response of the patient as well as whether damage will occur to the patient&#39;s eyelid and/or surrounding tissues. Depending on the severity of the patient&#39;s MGD or the patient&#39;s pain tolerance, elevated temperatures may be used with patient&#39;s on an individualized basis when applying heat. It has been found that lighter skinned patients can generally tolerate less heat than darker skinned patients, and darker skinned patients tend to exhibit less inflammation as a result of exposure to the heat. Other factors, including humidity, may contribute to a patient&#39;s tolerate to greater temperatures. For example, humans can generally tolerate heat up to 70 to 80 degrees Celsius in dry saunas where humidity is low. Application of heat in higher humidity environments may cause pain and/or burns to occur at lower temperatures. 
     Severe cases of MGD that cause substantial irritation or risk to the patient may even call for temperatures that would produce category one or two burns to the patient&#39;s eyelid, since these burns generally heal. Temperatures that cause category three burns should be avoided. In summary, treatment times and/or temperature can be adjusted to account for these differences. The present invention is not limited to any particular temperature or time ranges as long as therapeutic temperature is being applied. 
     The regulated heat can be maintained at a therapeutic temperature for a treatment period. The treatment period can be approximately 1 to 10 minutes for example. The heat could also be repeatedly applied and maintained for a desired period of time to keep the occlusion or obstruction in a melted, loosened, or softened state. Either during or after such treatment by regulated heat, mechanical expression of lipids and other fluids from the meibomian glands has been found to clear obstructions which have essentially melted or been placed in a suspension state (by virtue of melting materials binding solids together). 
     Optionally, after expression of the occlusions or obstructions is performed (step  44 ), an optional pharmacological agent may be applied to the meibomian gland to promote the free flow of sebum and/or reduce or prevent inflammation or infections of the eye or eyelids (step  46 ). Many pharmacological agents have been proposed for treatment of dry eye syndrome, any of which may be effective or more effective upon clearing of obstructions within the meibomian glands. Some of the pharmacological agents that may be utilized include, but are not limited to: antibiotics such as topical or oral tetracycline and chemically modified tetracycline, testosterone, topical or oral corticosteroids, topical androgens or androgen analogues, omega 3 fatty acid compounds such as fish oils, Laennec, enzymes that promote lipid production, agents that stimulate production of enzymes that promote lipid production, and/or any agent which acts as a secretagogue to enhance meibomian gland secretion or secretion of other tear components. For example, androgen and androgen analogues and TGF-beta have been reported to act as a secretagogue to enhance meibomian gland secretion. These compounds are illustrative examples of appropriate pharmacological agents, but those skilled in the art will appreciate that other pharmacological compounds may be utilized. 
     Also, agents, such as Restasis (cyclosporine A), that replace or promote production of the tear component may also be applied more effectively after treating the meibomian glands according to the present invention. Treating the meibomian glands improves the lipid layer, thus reducing evaporation and conserving the aqueous layer. Conservation of the aqueous layer reduces the need for tear substitutes to be applied through tear component agents. Thus, tear component agents may not have to be used as often when employing the present invention to treat a patient&#39;s MGD. 
     In the course of experimenting with the application of heat to the inside of the eyelid, it was also discovered that convective heat losses occur due to blood flow in the blood vessels located inside the eyelid. Blood flow through blood vessels located inside the eyelid produces convective heat losses. The blood flow serves as a natural “heat sink” provided by the body. Convective heat loss is lessened when applying heat to the inside of the eyelid than when applying heat to the outside of the eyelid. This is because fewer blood vessels are located between the meibomian glands and the inside of the eyelid than the outside of the eyelid. The meibomian glands are located closer to the inside of the eyelid. However, convective heat loss still occurs when heating the inside of the eyelid. However, if the blood flow were reduced, convective heat losses could be minimized allowing for temperatures to be attained and sustained at the meibomian glands in an even more efficient manner and in less time. 
     In this regard, an exemplary lid temperature profile  50  when heat is applied to the inside of the eyelid and force at various pressure levels is applied to the outside of the eyelid is illustrated in  FIG. 7 . There, a graph depicts the temperature at the inner and outer surface of an eyelid as a function of time when a source of constant heat and pressure is applied to an example subject patient. Initially, no heat or pressure is applied to the eyelid. In this example, the temperature at the inside of the eyelid is approximately 36 degrees Celsius while the temperature at the outside of the eyelid is approximately 35 degrees Celsius. When the heat source is turned on to apply heat to the inside of the eyelid and a 70 mm Hg pressure is applied to the outside of the eyelid, the temperature at the inside of the eyelid dramatically increases quickly. The pressure being applied to the eyelid is reducing blood flow in the eyelid, which reduces convective heat loss and increases conductive heat gain. The temperature at the outside of the eyelid increases quickly as well, but less dramatically than at the inside of the eyelid since the heat source is at the inside of the eyelid. A nominal temperature of approximately 40.5 and 38.3 degrees Celsius is reached at the inside and outside of the eyelid, respectively. 
     If the pressure is increased, even higher temperatures are attained as illustrated in  FIG. 4 . Finally, when the heat source is completely shut off, the temperature degrades. However, the temperature at the eyelid does not degrade immediately due to the force continuing to be applied. Again, the force reduces blood flow to prevent convective heat loss. If both heat and force are shut off after being applied, the temperature at the eyelid does degrade more rapidly. This is because blood flow in the eyelid is unobstructed, allowing the body&#39;s blow flow to “quickly convect the heat away. Thus, the lid temperature profile  50  of  FIG. 7  illustrates temperature at the eyelid can be increased effectively and quickly with the application of force in addition to heat. Note that the application of force to reduce convective heat loss can be applied whether heat is applied to the inside or outside of the eyelid. As illustrated in  FIG. 7 , the application of force is effective in both scenarios. 
     Thus, one embodiment of the present invention also includes the further application of force to the patient&#39;s eyelid in addition to heat. The application of force can further assist in obtaining higher temperatures more efficiently inside the eyelid at the palpebral conjunctiva and at the meibomian gland in a shorter period of time and thus more efficiently. This is because the application of force may reduce blood flow to the eyelid to reduce convective heat loss, as discussed above. 
     In this regard, an embodiment of the present invention to apply heat and force to the eyelid to treat MGD is illustrated in the flowchart of  FIG. 8 . First, heat is applied to the eyelid to raise the temperature at the meibomian glands to the desired level (step  60 ). For example, heat may be applied to raise the temperature at the inside of the eyelid to 44-47 degrees Celsius. The heat may be applied to the inside or outside of the eyelid, or both sides of the eyelid. The heat may also be regulated, meaning that a heating means or element is controlled to be within the temperatures and means that are safe for the eyelid and at a sufficient temperature for melting, loosening, or softening an occlusion or obstruction in the meibomian gland. A force is also applied to the eyelid to reduce blood flow in the eyelid to allow the applied heat to more quickly raise the temperature at the meibomian glands (step  62 ). The force may be applied to the inside or outside of the eyelid. 
     The heat and/or force may be maintained for a period of time sufficient to raise the temperature at the meibomian glands sufficient to melt, loosen, or soften the obstructions or occlusions (step  64 ). The force may be maintained after heat is removed, or vice versa depending on the treatment technique desired. Maintaining force after heat is removed may cause the temperature at the meibomian glands to dissipate more slowly than if force is removed. Maintaining heat without maintaining force may be employed to allow blood flow in the eyelids, such as between successive treatments. For example, it may be desirable to maintain heat to lessen the total amount of treatment time while applying and removing force between treatments. Also, it may not be necessary to apply significant amounts of force or for the same duration as heat if the obstruction or occlusion is located in close proximity to the lid margin rather than in the deeper portions of the meibomian gland. 
     Applying force can also result in a more efficient conductive heat transfer from an applied heat source, because the pressure created by the force causes the heat source to be compressed against the tissue of the eyelid. This compression can have several benefits. Compression spreads out the tissue to which heating is applied thus making it thinner and improving conductive heat transfer. Compression can also “squeeze out” air pockets at the surface of the eyelid due to the microscopic roughness of skin. Thus, compression of the heat source against the eyelid increases the surface contact between the heat source and the surface of the eyelid (which increases the heat transfer equation) to provide a more effective conductive heat transfer to the meibomian glands. This results in the meibomian glands being heated to the desired temperature level in a shorter period of time due to these gained efficiencies. Further, increased temperatures may be attained that may not have otherwise been obtained, or obtained using less heat or thermal energy. Because the heating is located in close proximity to the eyelid surface and heating is further compressed against the eyelid surface, heat transfer is very efficient providing for the temperature at the surface of the eyelid to be very close to the temperature at the meiboimian glands. 
     Further, note that while the exact reduction in times to heat the meibomian glands will vary from patient to patient when force is applied, and may be based on the amount of pressure applied to the patient&#39;s eyelid, in general, the change in heating times can vary by as much as several hundred percent, for example, when compared to previous methods. As an example, this can translate into five (5) or more minutes that one has to expel an obstruction or occlusion before such re-solidifies when compared with prior methods. 
     The force may be regulated, meaning that a force generating means is controlled to be within the pressure ranges that are safe to be applied to the eyelid and at sufficient pressure to allow the temperature at the meibomian gland to be raised sufficiently. The force can also be a constant force and be provided manually. For example, force may be provided by a technician or doctor&#39;s finger or thumb as heat is applied. The force may be applied during heating, after heating, or both during and after heating. In either case, the force may assist in expressing occlusions or obstructions when in a loosened, softened, or melted state from the meibomian glands. The force may include vibratory type forces, including those generated mechanically or those using fluid type devices or mechanisms. The force can be applied at a particular location or vector of the patient&#39;s eyelid to be specifically directed to the meibomian glands. This may reduce the level of force needed to express obstructions or occlusions in the glands. The level of force needed to express obstructions or occlusions in the glands may also be greatly reduced when heat is applied to the obstructions or occlusions to place them in a melted, softened, or loosened state. Other means for applying the force may be selected from one or more of a number of modalities wherein the frequency of vibration may be including low frequency vibration (generally less than 1000 Hz), sonic (generally 1000 Hz to 20,000 Hz) or ultrasonic energy (generally greater than 20,000 Hz), fluid jet such as air or water, microwave energy, needles, micro-needles, laser energy, RF energy, aspiration/suction, vacuum, pressure, compression and functional equivalents thereof. 
     The application of force can also stimulate the movement of fluids or suspensions of occlusions or obstructions from the glands. The present invention can be used with devices which generally apply a regulated force or milking action to the eyelid to express the fluids or suspensions or to otherwise mechanically stimulate the movement of fluids from the glands. In some instances, a small, gentle, continuous force applied to the eyelid will assist in expression of the fluids and suspensions. Vibration can also be used when applying force simultaneously or immediately after the heating to further assist in the expression. 
     Thereafter, either during heating and/or the application of force or after either, obstructions or occlusions in the meibomian glands may be expressed so that sebum flow is restored from the glands to establish a sufficient lipid layer (step  66 ). 
     Just as discussed above in the flowchart of  FIG. 6  where only heat is applied, the application of heat may be regulated. Regulated heat can include controlling heat according to a temperature profile. The temperature profile may be a constant temperature, include ramp-ups, ramp-downs, peaks and valleys. Further, the temperature profile may include heat pulses or be modulated with various characteristics, including the use of on/off switching or pulse width modulation (PWM) techniques for example. The use of modulated heat may allow the temperature to be raised even higher at the eyelid without damages to the patient&#39;s eyelid since the increased temperatures are applied for shorter periods of time. Obstructions or occlusions in the meibomian glands may have melting, loosening, or softening points that are beyond temperatures that may be applied without the use of modulated heat. The temperature needed to melt, loosen, or soften obstructions or occlusions may depend on how keratinized the obstruction or occlusion is. Not all obstructions or occlusions have the same melting, loosening, or softening points. 
     By example only, elevated temperatures between 45 and 55 degrees Celsius may be possible when applying regulated heat, especially if the eyelid has been anesthetized. However, heat must always be applied to the eyelid at temperatures that take into consideration the pain response of the patient as well as whether damage will occur to the patient&#39;s eyelid and/or surrounding tissues. Depending on the severity of the patient&#39;s MGD or the patient&#39;s pain tolerance, elevated temperatures may be used with patient&#39;s on an individualized basis when applying heat. It has been found that lighter skinned patients can generally tolerate less heat than darker skinned patients, and darker skinned patients tend to exhibit less inflammation as a result of exposure to the heat. Other factors, including humidity, may contribute to a patient&#39;s toleranc of greater temperatures. For example, humans can generally tolerate heat up to 70 to 80 degrees Celsius in dry saunas where humidity is low. Application of heat in higher humidity environments may cause pain and/or burns to occur at lower temperatures. 
     Severe cases of MGD that cause substantial irritation or risk to the patient may even call for temperatures that would produce category one or two burns to the patient&#39;s eyelid, since these burns generally heal. Temperatures that cause category three burns should be avoided. In summary, treatment times and/or temperature can be adjusted to account for these differences. The present invention is not limited to any particular temperature or time ranges as long as therapeutic temperature is being applied. 
     The regulated heat can be maintained at a therapeutic temperature for a treatment period. The treatment period can be approximately 1 to 10 minutes for example. The heat could also be repeatedly applied and maintained for a desired period of time to keep the occlusion or obstruction in a melted, loosened, or softened state. Either during or after such treatment by regulated heat, mechanical expression of lipids and other fluids from the meibomian glands has been found to clear obstructions which have essentially melted or been placed in a suspension state (by virtue of melting materials binding solids together). 
     Optionally, after expression of the occlusions or obstructions is performed (step  66 ), an optional pharmacological agent may be applied to the meibomian gland to promote the free flow of sebum and/or reduce or prevent inflammation or infections of the eye or eyelids (step  68 ). The discussion regarding use of pharmacological agents above for the flowchart in  FIG. 6  is equally applicable for this embodiment and thus will not be repeated here. Those compounds are illustrative examples of appropriate pharmacological agents, but those skilled in the art will appreciate that other pharmacological compounds may be utilized. 
     In one embodiment, a force can be applied to the outside of the eyelid while heat is applied to the inside of the eyelid to treat MGD. The heating of the inner surface of the upper or lower eyelid can be done by any convenient method. The lids can be heated one at a time or both at once, depending on the time available to remove the occlusions once heated. One device for heating the palpebral conjunctiva is illustrated in  FIGS. 9-14 . 
       FIG. 9  illustrates the overall device referred to as a heat and force application device  70 . In this embodiment, the heat and force application device  70  consists of a hand-held, battery-operated controller  72  that contains heat and pressure generating and regulation components. The controller  72  can also be a non hand-held device that is either mounted or rests on a table top, for example. The controller  72  as described herein is intended to describe and encompass any device, including but not limited to electronic and pneumatic controls and supporting components, that is adapted to allow and control the application of heat and/or force to the patient&#39;s eyelid. The controller  72  is connected to a disposable component  74 , via a controller interface  76 , to generate heat and force at an eyelid  78 , as illustrated in  FIG. 9 . The disposable component  74  consists of a lid warmer  90  provided in the form of a lens (illustrated in  FIGS. 10-12 ) that applies heat to the inside of the patent&#39;s eyelid and interfaces with an eye cup to apply force to the outside of the patient&#39;s eyelid (illustrated in  FIGS. 13-14 ). Both can be used in concert to treat MGD for a single eye. The interface  76  tubing can be wrapped around the patient&#39;s ear  77  with any excess clipped to the patient&#39;s clothing. The heat and force application device  70  is intended for use by physicians to apply localized heat and pressure therapy for treating MGD. 
     The controller  72  contains a user interface  80  to allow a physician or other technician to control the heat and force application device  70 . Temperature and pressure being applied to the patient&#39;s eyelid  78  can be seen on a temperature display  82  and a pressure display  84 . By observing temperature and pressure displays  82 ,  84 , the physician can determine when a therapeutic temperature and pressure have been reached. For example, the temperature and pressure displays  82 ,  84  may be segment bar graphs so that both the temperature and pressure levels and the increasing or decreasing nature of the temperature and pressure levels can be seen. The temperature level to be reached at the patient&#39;s eyelid can either be set to a static level within the controller  72 , or controllable by a physician or technician. The force and thus the pressure applied to the patient&#39;s eyelid is controllable by squeezing a force lever  86 . When a physician or technician desires to apply force, the force lever  86  can be squeezed. To release force and thus reduce pressure, the force lever  86  is disengaged. The pressure created by the force applied to the patient&#39;s eyelid is displayed on the pressure display  84 . 
     A timer display  88  can be provided on the controller  72  to display the amount of time that heat and/or force has been applied to the patient&#39;s eyelid  78 . The timer display  88  can display a cumulative amount of time passed or provide a countdown timer if an initial duration is set. For example, the timer display  88  may be comprised of a number of seven segment displays. In one embodiment, the timer display  88  will count down from one hundred eighty (180) seconds and will flash at one hundred twenty (120) seconds and sixty (60) seconds, which is an indicator to the physician to release the force lever  86  and then reapply force and pressure by squeezing the lever  86  again. 
       FIG. 10  illustrates the disposable component  74  in more detail. The disposable component  74  consists of a lid warmer  90  that includes a lens in the disclosed embodiment. The lens  90  contains a heating element to apply heat to a patient&#39;s eyelids  91 A,  91 B, but also provides an insulating back plate against which force may be applied. As illustrated in  FIG. 11 , the lens  90  is placed on the patient&#39;s eye with the patient&#39;s upper and lower eyelids  91 A,  91 B resting on the outside surface of the lens  92 . Before installation, the scleral side of lens  90  may be lubricated with saline, or equivalent lubricating drops. The lens  90  is then inserted onto the patient&#39;s eye under the eyelids  91 A,  91 B. A heating element (not shown) is contained within the lens  90  that can apply heat to the inside of the patient&#39;s eyelid when installed. The material used to construct the lens  90  is not electrically conductive, but is thermally conductive to allow heat from the heating element inside to be transferred to the patient&#39;s eyelid. The lens  90  can be constructed out of a plastic, including a clear plastic such as LEXAN HPS2 for example. Further, the lens  90  can be constructed from a biocompatible material, such as polymethylmethacrylate (PMMA), epoxy, or other materials well known to those skilled in the art. The lens  90  may be flexible, but ideally should be only minimally compressible to fit against the patient&#39;s eyeball. 
     The lens  90  also contains a lid warmer platform or tab  94  that is attached to the lens  90 . The lid warmer platform  94  may be connected perpendicularly to the lens  90  such that it extends away from the patient&#39;s eye when installed. The lid warmer platform  94  provides several benefits. First, provides a handle for insertion and movement or adjustment of the lens  90  and its heating element. Second, it provides a guide post for a compression force device to attach to apply a force to the patient&#39;s eyelid while the lens  90  applies heat to the inside of the patient&#39;s eyelid. It can also support a lens electrical interface  96  to allow the lens  90  to electrically connect the heating element inside the lens  90  to the controller  72  via the interface  76 . The controller  72  can then apply electrical energy to the heating element to generate heat within the lens  90  and thus to the inside of the patient&#39;s eyelid when installed. Second, it provides a support structure for interface circuitry  98 . The interface circuitry  98  provides electrical connections for energizing the heating element and communicating temperature measured at the lens  90  back to the controller  72  for heat regulation. The interface circuitry  98  will discussed later in this application and in regard to  FIG. 16 . 
       FIG. 12  illustrates a cross-sectional view of the lid warmer employing the lens  90  illustrated in  FIGS. 9-11  to further illustrate heat delivery components and features of the lid warmer, according to one embodiment of the present invention. The lens  90  is formed by a scleral side  93  being attached to an eyelid side  92 . The scleral side  93  of the lens  90  contains a bend  100  around its circumference edge to provide an attachment edge  102  to support attachment of the eyelid side  92 . Because of the bend  100 , a hollow chamber  104  is formed inside the lens  90 . The hollow chamber  104  supports a heating element  106  contained inside the lens  90  to generate heat when energized. The heating element  106  abuts against the eyelid side  92  of the lens  90  so that the heat generated is located adjacent the inner eyelid to apply heat to the meibomian glands. The heating element  106  is attached to the interface circuitry  98  via a fused link  108 , which is then attached to the controller  72  via the lid warmer platform  94  being attached to the controller interface  76 . In this manner, the controller  72  can cause the heating element  106  inside the lens  90  to generate heat by applying an electrical signal to the interface circuitry  98  which is connected to the heating element  106 . If the temperature exceeds the threshold temperature level of the fused link  108 , the link  108  would melt and create an open circuit to disable the heating element  106  for safety reasons. Alternatively, the fused link  108  could be a thermal link provided as an integrated part of the heating element such that the fused link  108  would melt and create an open circuit at a given threshold temperature. 
     The heating element  106  may be provided in any form or material. The heating element  106  may be a resistive type heater, a thick film heater, or any one of a number of other types, such as a “flex circuit” (etched metal on flexible substrate) well known to those skilled in the art. The heating element  106  can be formed to the shape of the lens  90 . In the illustrated example, the heating element  106  is a material that is both electrically and thermally conductive. This may be important. The electrical conductivity characteristic allows current to be applied to the heating element  106  to generate resistive heat. The thermal conductivity characteristic serves to evenly distributes the resistive heat over the entire heating element  106  to more evenly distribute the heat to the patient&#39;s eyelid. Without these characteristics, it may be more difficult to regulate heat generated by the heating element to efficiently and effectively melt, loosen, or soften obstructions or occlusions in the meibomian glands. Examples include the E5101 carbon-loaded polyphenylene sulfide and the E2 liquid crystal polymer, both manufactured by Cool Polymers, Inc. 
     The size of the lens  90  may also play a part in the heating element  106  selection and the amount of heat it must generate to be effective in MGD treatment. The lens  90  distributes heat generated by the heating element  106 . A larger lens  90  may distribute the heat generated by the heating element  106  more uniformly and over a larger surface area. Also note that the application of heat to the patient&#39;s eyelid does not necessarily have to include an embedded heating element  106  in the lens  90 . Heat application may be provided as part of the environment, such as air for example. The amount of heat applied, the temperature reached at the meibomian glands as a result, where the heat is applied on the patient&#39;s eyelid or surrounding tissue, and the duration of heat applied can control the selection of the heating source. 
     In addition to the insulation provided by the material used to construct the lens  90 , the lens  90  may also contain an integrated insulator inside the chamber  104  as an additional measure of insulation. Insulation prevents substantial heat from reaching the eyeball and thus protects the cornea and sclera. As employed herein, the term “insulate” or “insulation” is intended to include any component or material and/or specific geometries of components or materials, wherein there is greater resistance to thermal conduction or radiation towards the surface of the eye than towards the eyelid. Stated alternatively, in the insulator thermal energy radiates more easily towards the eyelid  91 A,  91 B than towards the eyeball surface in order to minimize the possibility of causing injury to the eyeball. In the lens  90  example of  FIG. 12 , the integrated insulator is air and is formed by the natural gap that exists by the space left by the heating element  106  not filling up the entire volume of the chamber  104 . The heating element  106  is biased according to its location in the lens  90 , and in particular to be located behind the integrated insulator, to produce more heat on the insides of the patient&#39;s eyelid than on their eyeball. 
       FIG. 13A  illustrates an eyecup  110  that is adapted to allow the controller  72  to apply a force to the patient&#39;s eyelids  91 A,  91 B in addition to heat. The eyecup  110  is acurved carrier  112  that supports an inflatable bladder  114 . The inflatable bladder  114  is attached to the curved carrier  112 . The inflatable bladder  114  is then connected to the controller  72  via a tubing  118  in the controller interface  76  (see  FIG. 14 ) such that the controller  72  can pump air into the tubing  118  to inflate the inflatable bladder  114 . When inflated, the eyecup  110  applies force to the outside of the eyelid  91 A,  91 B while heat can be applied via the lens  90  and heating element  106 . To apply force to the patient&#39;s eyelids  91 A,  91 B, the bladder  114  is inflated under control of the controller  72 . To release the force and thus reduce pressure, the air in the bladder  114  is released by the controller  72 . 
     When desired to be used, the lid warmer platform  94  is inserted into an eyecup orifice or slot  113  in the eyecup  110  between a latching mechanism  116 . The latching mechanism  116  provides a means to secure the lid warmer platform  94  to the eyecup  110  when in use as well as provide an interface to electrically connect the lid warmer electrical interface  96  to the controller  72  via the controller interface  76 . The latching mechanism  116  is comprised of a carrier  117  having a semi-circular carrier base  119 . The carrier base  119  receives an eyecup platform  121  attached to the eyecup  110 . The carrier base  119  and eyecup platform  121  can be squeezed together like a clip to control an opening through which the lid warmer platform  94  is inserted into the carrier  117  when inserted into the orifice  113  of the eyecup  110 . When the carrier base  119  is not squeezed against the eyecup platform  121 , the carrier opening through which the lid warmer platform  94  is inserted closes to secure the lid warmer platform  94  to the carrier  117 , and thus the eyecup  110 . The eyecup platform  119  is adapted to allow the lid warmer platform  94  to rest on top when inserted into the eyecup orifice  113 . When inserted, the electrical interface  96  of the lid warmer  74  contacts a carrier interface  123 , which provides an electrical connection between the electrical interface  96  and the controller interface  76 . 
       FIG. 13B  illustrates an alternative latching mechanism  116 A to one illustrated in  FIG. 13A . The latching mechanism  116  is compressed in the horizontal plane while the eyecup  110  is moved forward along the lid warmer tab  94  until it rests against the outside of the patient&#39;s eyelids  91 A,  91 B. When the latching mechanism  116  is released, the eyecup  110  is fixed in place in its location along the lid warmer tab  94 . In this manner, the patient&#39;s eyelids  91 A,  91 B are “sandwiched” between the lens  90  and the eyecup  110 . More information and detail regarding the latching mechanism  116  is illustrated in  FIGS. 27-30  and will be described later in this application. 
       FIG. 14  illustrates more detail regarding the controller interface  76 . The controller interface  76  couples the controller  72  to the lens  90  and eyecup  110  to allow the controller  72  to controllably apply heat and/or force to the patient&#39;s eyelid as part of a MGD treatment. The controller interface  76  contains a connector  120  on one end that connects to the controller  72 . The connector  120  includes both an electrical interface  122  and a pneumatic interface  124 . The electrical interface  122  allows the controller  72  to send and receive electrical signals over an electronics wiring  126  to and from the lid warmer  90 , as will be described in more detail below. The electronics wiring  126  interfaces with an eyecup electrical connector  128  on the eyecup  110  such that the lid warmer electrical interface  96  of the lid warmer  90  is connected to the electronics wiring  126  when the lid warmer platform  94  is inserted into the eyecup  110 , as illustrated in the examples of  FIGS. 13A and 13B . The pneumatic interface  124  allows the controller  72  to pump into the tubing  118  to inflate the inflatable bladder  114  on the eyecup  110  to apply force to the patient&#39;s eye and to deflate the air in the inflatable bladder  114  to release force and relieve pressure. In the illustrated embodiment, the pneumatic interface  124  is securely coupled to the inflatable bladder  114  on the eyecup  110 . 
       FIG. 15  supplements  FIG. 14  to illustrate the interface components between the controller  72  and the disposable component  74  and the eyecup  110 , at a system level. The controller  72  of the heat and force application device  70  contains a pressure control system  130  and a temperature control system  132 . The pressure control system  130  is the control component within the controller  72  that controls the pressure from the force applied to the patient&#39;s eye via the eyecup  110 . The temperature control system  132  is the control component within the controller  72  that controls the heat applied to the patient&#39;s eye via the lid warmer  90 . The pressure control system  130  also communicates the pressure in the tubing  118  to a pressure sensor  134  within the pressure control system  130 . The pressure sensor  134  is used to determine the pressure level in the tubing  118  to display the pressure on the pressure display  84  as well as to provide feedback to the controller  72  to provide the various functions and controls for the system, as will be described in more detail below. The pressure sensor  134  also allows the recordation of pressure data to be recorded by the controller  72 , or an external data acquisition device (not shown) coupled to the controller  72 , if desired. 
       FIG. 15  also illustrates more detail regarding the latching mechanism  116  on the eyecup  90 . The latching mechanism  116 A facilitates providing a connection between the lid warmer  90  and the lid warmer platform  94  and the eyecup  110 , and the lid warmer  90  to the electronics wiring  126  when the eyecup orifice  113  is slipped over to the lens platform  94  to secure the eyecup  110  to the patient&#39;s eyelid. Two different types of latching mechanism  116 ,  116 A were previously illustrated in  FIGS. 13A and 13B , either of which can be used to secure the platform  94  to the eyecup  110 , or any other type may be used. 
       FIG. 16  illustrates the specific wiring and supporting circuitry that comprises the electronics wiring  126  to interface the controller  72 , and particularly the temperature control system  132 , to the lid warmer  90  to apply heat to the patient&#39;s eye for the disclosed embodiment. Six wires make up the electronics wiring  126 . The six interface wires are connected to the interface circuitry  98  that is embedded in the disposable component  74 . HEATER+ and HEATER− are connected to the heating element  106  in the lid warmer  90  when the platform  94  is connected to the controller interface  76 . THERM 1 + and THERM 2 + are coupled to two thermistors  136 A,  136 B. The two thermistors  136 A,  136 B provide an indication of temperature at the patient&#39;s eyelid as part of a temperature feedback mechanism to allow the temperature control system  132  to monitor the temperature for control. Because in the preferred embodiment, the temperature drop between the heating element  106  and the inside of the patient&#39;s eyelid is minimal, regulating temperature is simpler. This is because the thermistors  136 A,  136 B record temperatures closer to the actual temperatures at the glands and thus temperature overshooting is minimized. It is important to attempt to minimize temperature overshoot so as to not damage the patient&#39;s tissue. Temperature thermostats or other more complicated regulation circuits may be employed to regulate temperature as well if desired, especially if temperature overshooting is an issue. Further, the size of the heating element and power supply could also be selected so that only a known maximum amount of heat could be generated even if the heating element  106  were energized all the time. This would avoid use of a regulation circuit to prevent temperature overshoot. 
     Two thermistors  136 A,  136 B are provided for redundancy and error checking in the event one fails. Both thermistors  136 A,  136 B should provide the same signal indicative of temperature. Both thermistors are coupled to a common RETURN to provide common current return/grounding. Lastly, a FUSE line is provided and linked to a fuse  138 , which is also coupled to the RETURN line. As will be discussed later in this application, the controller  72  can send a current over the FUSE line sufficient to blow fuse  138 . The controller  72  can blow the fuse  138  to provide an indication that the lid warmer  90  has been previously used. Thus, if the lid warmer  90  is reused, the controller  72  can detect the open circuit on the FUSE line and know that the fuse  138  has been previously blown. 
       FIG. 17  illustrates additional components of the pressure control system  130  to provide more detail for the disclosed embodiment. The pressure control system  130  contains an electric pump  139  to pump air into the tubing  118 . Other types of pumps may be used. A check valve  140  is provided inline in the tubing  118  between the electric pump  139  and the inflatable bladder  114  to allow the controller  72  to draw in air to the system to use to inflate the inflatable bladder  114  without backflow release. A relief valve  141  is also provided as a safety measure to ensure that line pressure to the eyecup  110  does not exceed maximum pressure settings in the controller  72 . As illustrated in  FIG. 15  and discussed above, the pressure sensor  134  is coupled to the tubing  118  to communicate the pressure in the tubing  118  to the pressure control system  130  for various functions. 
       FIG. 18  illustrates the temperature control system  132  in more detail for the preferred embodiment. The temperature control system  132  includes a power system  142  to provide power to the system components. In the disclosed embodiment, batteries  144  are used as the power supply. Energy from the batteries  144  are provided to a reverse battery protection and low battery detection circuit  146 . If the batteries  144  are low in power, a low battery signal is communicated over a low battery signal line  148  to a timer and display controller  150 . The timer and display controller  150  is responsible for controlling therapy timers and displaying them on the timer display  88 . The timer and display controller  150  is also used to communicate other codes to the user regarding the controller  72 , including the low battery signal. The energy from the batteries  144  are also routed to various DC-DC converters  152  to provide various voltage levels needed by the controller  72  and its components for operation. Note that the present invention is not limited to any particular type of power system or specific power components. 
     The temperature control system  132  may also contain a data interface  154  to provide pressure and temperature data to a data logger  156 . The data logger  156  may also contain a timer interface  158  to the timer and display controller  150  so that times can be recorded for the data. The data logger  156  may be used to record data regarding patient treatments for analysis and/or to provide data for test purposes. The data logger  156  may be coupled to a test connector  160  so that logged data regarding the system may be viewed and/or recorded via an external device (not shown) coupled to the test connector  160 . 
     The remainder of the temperature control system  132  consists of various components of the controller  72  that provide the overall operation and control of the heat and force application device  70 . These components are provided in the form of various circuits and control components, including programmable gate arrays (PGA). The components interact together to provide a system logic for operation of the system. These components will be described in conjunction with  FIGS. 21-26  below, which describe the logic control of the system. Note that these components can be provided by either analog or digital circuitry, and can be provided using a microprocessor-based architecting, including software, if desired. 
       FIGS. 21-26  illustrate the state machine of the controller  72  and the various operations performed in the states that provide the operation and logic of the heat and force application device  70 . However, before turning the state machines and the logic of the various states, a high level overall operation of the controller  72  is described with respect to the flowchart of  FIG. 19 .  FIG. 19  will be discussed in conjunction with the various states that make up the state machine of the controller  72  illustrated in  FIG. 19 . 
       FIG. 19  illustrates a flowchart which describes the overall operation and logic of the heat and force application device  70  that is carried out by the controller  72  and its systems, including the pressure control system  130  and the temperature control system  132 , according to an embodiment of the present invention. The process starts by the controller  72  resetting in the reset state (step  200  in  FIG. 19 , reset state  220  in  FIG. 20 ). The controller  72  always starts in a reset state in the disclosed embodiment. The reset state may occur as a result of a power cycle or if a new disposable component  74  is connected to the controller  72 . After resetting, the controller  72  performs a series of tests prior to beginning treatment to determine if the controller  72  and its components are operating properly (decision  202  in  FIG. 19 ). If not, an error is noted and the controller  72  stops operation by entering into the stop state (step  204  in  FIG. 19 , stop state  224  in  FIG. 20 ). The stop state disables the heater. If the controller  72  is operating properly (decision  202  in  FIG. 19 ), the controller  72  proceeds with the operations to begin a treatment by entering the run and monitor states (states  226  and  228  in  FIG. 20 ). 
     As an option, the controller  72  may first blow a fuse on the lid warmer  90  to create an open circuit in a fuse blow state (step  205  in  FIG. 19 , fuse blow state  222  in  FIG. 20 ). This is so a lid warmer  90  cannot be reused for subsequent treatments for safety and contamination reasons. As part of the operation check in decision  202 , the controller  72  may determine if the fuse on the lid warmer  90  has been blown in the reset state ( 220  in  FIG. 20 ). If so, this would be an indication that the lid warmer  90  has already been used, and the controller  72  would enter the stop state (step  204  in  FIG. 19 , stop state  224  in  FIG. 20 ). The controller  72  will continue to allow operation with the installed lid warmer  90  after the fuse is blown until the lid warmer  90  is removed. In such case, the controller  72  will enter the reset state (step  200  in  FIG. 19 , reset state  220  in  FIG. 20 ). 
     Next, the controller  72  prepares for a therapy. The controller  72  may first initialize therapy timers in the timer and display controller  150 . Timers allow the user of the controller  72  to track the amount of time that therapy has occurred, including heat and force application. Different patients may require different amounts of time for the application of heat and force during treatments. For example, a treatment cycle may include the application of heat for three minutes, but force may need to be applied, disengaged, and reapplied several times during the three minute therapy time period. 
     Subsequently, the controller  72  enables the temperature control system  132  and the pressure control system  130  to apply heat and force to the patient&#39;s eyelid as part of a run state (step  208  in  FIG. 19 , run state  226  in  FIG. 20 ). In the disclosed embodiment of the lid warmer  90  and eyecup  110 , heat is applied to the inside of the patient&#39;s eyelid, and force is applied to the outside of the patient&#39;s eyelid, as previously discussed. However, note that the controller  72  could also be used to apply heat and/or force to any part of the patient&#39;s eye or supporting structure, including but not limited to both to the outside of the patient&#39;s eyelid, and heat to the outside and force to the inside of the patient&#39;s eyelid. The controller  72  then monitors the temperature and force applied to the patient&#39;s eyelid as part of the heat and pressure regulation in a monitor state (step  210  in  FIG. 19 , monitor state  228  in  FIG. 20 ). The run and monitor states  226 ,  228  operate simultaneously in the preferred embodiment so that heat and force are constantly being applied and temperature and pressure monitored during therapy. If during the run or monitor  226 ,  228 , an error is detected (decision  212  in  FIG. 19 ), the controller  72  enters the stop state to discontinue therapy (step  216  in  FIG. 19 , stop state  224  in  FIG. 20 ). If an error is not detected, the run and monitor states  226 ,  228  continue until either an error is detected (decision  212  in  FIG. 19 ) or the therapy is completed (decision  214  in  FIG. 19 ). 
       FIGS. 21-26  illustrate flowcharts that detail the operation of the various states executed by the controller  72  to control temperature and pressure to provide MGD treatment, according to the disclosed embodiment. Each of these states were described generally above with respect to the flowchart in  FIG. 19  and the state diagram in  FIG. 20 . Now, each state and their specific operations and functionalities as it contributes towards the operation of the heat and force application device  70  and its controller  72  will be described in more detail. Since some operations require information from various components in the pressure and temperature control systems  130 ,  132 , references to these various components will be made as the operations of the states are described. This includes reference to components previously and not previously introduced in the temperature control system  132  in  FIG. 18 . 
       FIG. 21  illustrates a flowchart of the reset state  220  (step  230 ). The controller  72  enters the reset state  220  when either a power cycle occurs or a new disposable lid warmer  90  (with an intact fuse  138  as an optional feature) is installed (step  232 ). Thereafter, the controller  72  checks to determine if the power supply voltage is above a set minimum voltage level (decision  234 ). In the disclosed embodiment, the batteries  144  must provide at least 2.4 Volts. If they do not, an battery error (e.g. “bAt”) is displayed on the timer display  88  (step  236 ). Referring to  FIG. 19 , the low battery error is displayed by timer and display controller  150  on the timer display  88  in response to the low battery signal sent from the low battery detection circuit  146  over the low battery signal line  148 . 
     If the batteries  144  are producing a sufficient voltage, the controller  72  continues with the reset state  220  by next determining if the disposable component  74  is installed (decision  238 ). If not, the controller  72  is not ready for operation. However, before going to the stop state  224  (step  246 ), the controller  72  takes the opportunity to perform a pressure diagnostic test. Referring to  FIG. 18 , the pressure sensor  134  signal indicative of measured pressure in the tubing  118  is communicated to a pressure level comparator  162 , which communicates the pressure level to the pressure display  84  and to an error checking control system  164 . Ideally, the pressure in the tubing  118  should not be greater than ambient pressure. If the pressure sensor  134  does not provide a signal indicative of ambient pressure (decision  240 ), this is an indication that the pressure sensor  134  may not be operating properly. Thus, a pressure sensor  134  error message (e.g. “E_ 4 ”) may be displayed on the timer display  88  (step  244 ), via the ERRORS signal line  171  (see  FIG. 18 ), before the controller enters the stop state  224  (step  246 ). If the pressure sensor  134  is properly measuring pressure, the timer display  88  remains in the reset display state (e.g. “ — — — ”) (step  244 ) and the controller  72  waits until a disposable component  74  is installed (decision  238 ). Note that because ambient pressure may not be 0 mm Hg depending on where the heat and force application device  70  is located, a threshold pressure level is used. In the disclosed embodiment, the threshold pressure level is 1 psi. 
     Once the disposable component  74  is installed, the controller  72  can next optionally determine if the fuse  138  on the lid warmer  90  is blown (decision  248 ). This check is only performed if the lid warmer  90  is equipped with a fuse  138  that can be blown by the controller  72  to indicate when the disposable component  74  has been previously used for a treatment. In this instance and referring to  FIG. 18 , a fuse detect and blow circuit  168  communicates a fuse detect signal over the FUSE DETECT line  173  from the interface circuitry  98  on the disposable component  74  to the error check controls system  164 . This is so the controller  72  can determine if the disposable component  74  has been previously used. If the fuse  138  is blown, the controller  72  will not allow therapy to be provided using the currently installed disposable component  74  for safety and sterility reasons until the disposable component  74  is replaced with a previously unused disposable one (which will have an intact fuse  138  on the interface circuitry  98 ). The controller  72  will display an error message (e.g. “E_ 1 ”) on the timer display  88 , via the FUSE signal line  170  to indicate to the user that the disposable component  74  must be replaced (step  250 ) before going to the stop state  224  (step  252 ). 
     If the fuse  138  is not blown on the disposable component  74  (decision  248 ) or if the fuse check feature is not included in the controller  72 , the controller  72  next determines if the heating element  106  is connected (decision  253 ). If not, the controller displays a connect message (e.g. “Con”) on the timer display  88  to indicate to the user that the heating element  106  (i.e. the lid warmer  90 ) is not connected to the controller  72  and thus therapy cannot begin (step  255 ). Once the heating element  106  is connected to the controller  72 , the controller  72  next determines if the temperature level at the lid warmer  90  is lower than room or ambient temperature (decision  254 ). If so, this is an indication that the disposable component  74  may not be installed on a patient&#39;s eyelid such that the user is ready for the controller  72  to begin therapy. Referring to  FIG. 18 , thermistor conditioning circuits  172 A,  172 B communicate signals from each of the thermistors  136 A,  136 B at the disposable component  74  to the error checking control system  164 . In response, the connect message (e.g. “Con”) may again be displayed on the timer display  88  (step  255 ). The controller  72  will continue to check the heating element  106  connection and the temperature at the lid warmer  90  until the thermistors  136 A,  136 B read a temperature of room temperature or greater (decision  254 ). This provides some assurance that the disposable component  74  is installed on the patient. 
     Next, the controller  72  will check to determine if the temperature level at the lid warmer  90  is lower than body temperature (e.g. 30 degrees Celsius) (decision  254 ). This enables the controller  72  to determine if the disposable component  74  is installed on the patient&#39;s eye, because if so installed, the temperature at the lid warmer  90  should be at least body temperature. If the temperature at the lid warmer  90  is not at least body temperature, an error message (e.g. “LO”) may be displayed on the timer display  88  in response to indicate to the user that the temperature at the lid warmer  90  is abnormally low (step  256 ). The controller  72  will thereafter cycle back through the series of checks to ensure that the lid warmer  90  is properly installed and ready for use in therapy (decisions  253 ,  257 ,  254 ,  258 ). 
     Once the temperature of the lid warmer  90  is at or above room temperature (decision  254 ), the controller  72  then determines if the temperature at the lid warmer  90  is at a temperature level that is higher than would be expected before therapy has begun (i.e. an over temperature level, e.g. 30 degrees Celsius) (decision  258 ). This may be indicative of an ambient temperature that is deemed to high to begin therapy. If so, an error message (e.g. “E_ 6 ”) may be displayed on the timer display  88  by the error check control system  164  (step  260 ) before the controller  72  enters the stop state  224  (step  262 ). If not, the controller will check the pressure level in the tubing  118 , via the pressure sensor  134 , to ensure pressure level is at ambient pressure since the controller  72  has not inflated the bladder  114  to generate a pressure to the patient&#39;s eyelid (decision  264 ). If the pressure level is lower than ambient pressure, this may be an indication of an error, such as an error with the pressure sensor  134  or the power source. If the pressure level is lower than ambient pressure, the controller  72  will check to determine if the battery voltage is sufficient (decision  261 ) and repeat through the series of checks (decisions  253 ,  257 ,  254 ,  258 ,  264 ) before allowing therapy to start. Once these series of checks have been satisfied, therapy can begin. In response, the controller  72  will cause the timer display  88  to be reset to indicate the beginning of a therapy session (e.g. a 180 second countdown) (step  265 ). The controller  72  will then check to ensure that the pressure level in the tubing  118  is not higher than ambient pressure or a desired pressure level that would be indicative of a pressure sensor  134  or other problem (decisions  267 , steps  269 ,  271 ) before proceeding to the run state  226 , or the fuse blow state  222  if provided (step  268 ). 
     After leaving the reset state  220 , the controller  72  may go into the fuse blow state  222  (step  272 ), which is illustrated in  FIG. 22 . If provided, the controller  72  blows the fuse  138  on the lid warmer  90  so that it cannot be reused after the controller  72  is reset (step  273 ). Referring to  FIG. 18 , the error checking control system  164  causes a sufficient current to be sent over the FUSE BLOW line  174  and to the fuse detect and blow circuitry  168  to blow the fuse  138  at the disposable component  74 . The controller  72 , via the error check control system  164 , then checks to see if the fuse  138  was successfully blown via the FUSE DETECT line  173  (decision  274 ). If not, and after seven unsuccessful attempts to do so (decision  276 ), an error message (e.g. “E_ 7 ”) may be generated on the timer display  88  (step  278 ) before going to the stop state  224  (step  280 ). It the fuse  138  is successfully blown, the controller  72  is ready to provide therapy. The controller  72  enters the run and monitor states  226 ,  228  (step  282 ) to be executed simultaneously to apply heat and force to the patient&#39;s eyelid as well as monitor the temperature and pressure applied for control purposes. 
       FIG. 23  illustrates the run state  226  (step  300 ). The controller  72  enters the run state  226  to begin therapy either from the reset state  220  (step  268  in  FIG. 21 ) or optionally from the fuse blow state  222  (step  282  in  FIG. 22 ). The run state  226  will be discussed before the monitor state  228 , which is illustrated in  FIGS. 25A and 25B . Turning to  FIG. 23 , the run state  226  begins by the controller  72  initializing a cycle timer and beginning a count down timer at the count down time value programmed into the system (step  302 ). Turning to  FIG. 18 , the timer and display controller  150  resets the timers. The count down timer is displayed on the timer display  88 . The cycle timer will cause the timer display  88  to blink at the end of a cycle such that the timer display  88  is used to provide the cycle timer and countdown timer information to a user. 
     In the disclosed embodiment, the cycle timer is the amount of time that force should be applied continuously to the patient&#39;s eyelid before being released. In the disclosed embodiment, this is set at one minute. The count down timer is the total therapy time for heat to be applied to the patient&#39;s eyelid. In the disclosed embodiment, the count down timer is set at three minutes. Thus, there will be three cycles during the therapy. The timers are not only used to provide a visual timing indicator to the user, but are also used to control heat and force application to the patient&#39;s eyelid as will be further discussed. These timer values could also be based on programming instructions provided by the user to the controller  72 . 
     Thereafter, the temperature control system  132  enables heat to be applied to the patient&#39;s eyelid via the lid warmer  90  and its lens (step  304 ). The beginning of heat therapy is signaled to the user by flashing the decimal point on the timer display  88  in the disclosed embodiment (step  304 ). Referring to  FIG. 18 , the therapy timer controller  150  causes an enable signal to be generated over an ENABLE line  176  to activate a lid warmer controller  178  to apply an electrical signal to the HEATER+ and HEATER− lines in the electronics wiring  126  (see  FIG. 16 ). This causes the heating element  106  in the lid warmer  90  to energize and generate heat to the patient&#39;s eyelid. The lid warmer controller  178  controls the heating element by turning on and off the electrical signal to the heating element  106 . However, any type of heating control can be employed, including but not limited to PWM techniques. Thereafter, the timer and display controller  150  determines if the cycle timer has not expired (decision  306 ). If it has expired, the therapy timer is paused (step  308 ) and the pause state  229  is entered (step  310 ). This is because the force must be released before therapy can continue. The pause state  229  is illustrated in  FIG. 24  and will be discussed later below. 
     If the cycle timer has not expired (decision  306 ), a start, alert, therapeutic temperature, and therapeutic pressure flags are checked (decisions  312 ,  314 ,  316 ,  318 ). These flags are set by the monitor state  228  as part of error checking, which is illustrated in  FIGS. 25A and 25B  and will be discussed later below. At this point, all that is required to understand is that these flags being set means that heat therapy can continue. If not, either the stop state  224  (step  317 ) or the pause therapy timer state  229  (step  308 ,  317 ) will be entered before returning back to the run state  226 . If the flags are properly set, the therapy timer will be decremented with the elapsed time as each second elapses (steps  319 ,  320 ) with heating element  106  continuing to be energized to produce heat at the lid warmer  90  until the therapy time is complete (decision  322 ). When the therapy time has completed, meaning that the therapy timer time has counted down to zero time in the disclosed embodiment, the therapy timer is stopped (step  324 ) and the stop state  224  is entered to discontinue heating the patient&#39;s eyelid (step  326 ). 
     Before describing the monitor state  228 , which is illustrated in  FIGS. 25A and 25B , the pause state  229  will next be described. The pause state  229  is illustrated in  FIG. 24 . The pause state  229  is entered to disable energizing the heating element  106  and wait for the user to release the force lever  86  (or other pressure control mechanism) before re-entering the run state  226 . This ensures that force is not continuously applied to the patient&#39;s eyelid during the entire therapy session without some relief to allow blood flow in the eyelids for safety precaution reasons. The timer and display controller  150  first disables the heating element  106  by removing the enable signal from the ENABLE line  176  to the lid warmer controller  178  (step  332 ). The timer display  88  is paused from changing, and the cycle time is flashed indicating that the end of the cycle has occurred (steps  334 ,  338 ). The start flag is checked (decisions  336 ,  340 ) to ensure that the user has released force so that therapy can be restarted, in which case the system returns back to the run state  226  (step  342 ). The start flag is set and reset in the monitor state  228 . 
     If the start flag is set (decision  336 ,  340 ), the controller  72  may also check to determine if the temperature at the lid warmer  90  is above a defined threshold temperature level. If so, this may be indicative of the heating element  106  producing a heat exceeding an upper temperature level of heat to be applied to the patient (decisions  337 ,  343 ). In the disclosed embodiment, this upper temperature threshold level is 43 degrees Celsius. However, this threshold temperature level can be set to be any temperature level threshold desired. If the threshold temperature level is exceeded, the temperature display  82  may be flashed to indicate this condition to the user as well as an error (e.g. “E_ 3 ”) being displayed on the timer display  88  (step  341 ,  343 ) before the controller  72  enters the stop state  224  (steps  343 ,  349 ). 
     The monitor state  228  is illustrated by the flowchart of  FIGS. 25A and 25B . The monitor state  228  will continuously check the temperature and pressure applied to the patient&#39;s eyelid. Temperature is checked using thermistors  136 A,  136 B, and pressure is checked using pressure sensor  134  coupled to the tubing  118 . The results of the measured temperature and pressure are displayed on the controller  72 , via the temperature and pressure displays  82 ,  84 . The temperature and pressure measurements are analyzed to ensure that no error conditions have occurred. In addition, the monitor state  228  will signal to the run state  226 , which is executing simultaneously with the monitor state  228 , when therapeutic temperatures and pressures have been reached. 
     Turning to  FIG. 25A , the temperature control system  132  determines if the temperature is above a threshold maximum temperature level failsafe for safety reasons (decision  352 ). This threshold maximum temperature level may be set to 45 degrees Celsius. If so, the over temperature condition is flashed on the temperature display  82  to indicate to the user that the temperature is over the allowed temperature setting (step  354 ). Further, an error message (e.g. “E_ 3 ”) may be displayed on the timer display  88  in the same regard (step  356 ). The controller  72  will enter the stop state  224  (step  358 ) to halt therapy. If the temperature at the lid warmer  90  is not above the set safe temperature threshold, the error checking controller checks to see if the two temperature thermistors  136 A,  136 B are different in value (decision  360 ). The thermistor  136 A,  136 B providing the higher reading is used for temperature monitoring as an additional precaution to prevent an unsafe temperature from being applied to the patient&#39;s eyelid (steps  362 ,  364 ). The measured temperature is then displayed on the temperature display  82  (step  366 ). 
     The temperature at the thermistor  136 A,  136 B used to measure the temperature is checked again to ensure that the temperature at the lid warmer  90  has not exceeded the maximum allowable temperature again as a safety precaution (decision  368 ). If the temperature has exceeded the maximum allowable temperature, the same steps previously performed earlier for this check are performed (steps  354 ,  356 ,  358 ). If not, the heater switch driver in the lid warmer controller  178  may be optionally checked to ensure that it is working correctly to ensure that heat will not be applied to the patient&#39;s eyelid when the switch is turned off via the ON/OFF signal line  180  in  FIG. 18  (decision  370 ). If the heater switch driver has a malfunction, and error message (e.g. “E_ 7 ”) may be generated on the timer display  88  to indicate the hardware failure to the user (step  372 ). The system then enters the stop state ( 224 ) to disable the application of heat (step  374 ). 
     If the heater switch driver is operating properly (decision  370 ), the system determines if the pressure level in the tubing  118  is above the maximum allowable pressure as a safety precaution to prevent too much pressure from being applied to the patient&#39;s eyelid (decision  376 ). If so, the over pressure condition is displayed on the pressure display  84  and the timer display (e.g. “E_ 5 ”) to indicate the over pressure condition to the user (step  378 ,  380 ) before entering the stop state  224  (step  382 ). If no over pressure condition exists, the measured pressure is displayed on the pressure display  84  (step  384 ). 
     Next, as illustrated in  FIG. 25B , the system determines if the temperature at the lid warmer  90  is above the therapeutic temperature setting (decision  386 ). This is an indication that the temperature has risen at the lid warmer  90  necessary to provide therapy and so that the therapy timer will accumulate in the run state  226 . The therapeuctic temperature setting is set by the system. Alternatively, it may be programmed by the user into the controller  72 . If the temperature is above the therapeutic temperature setting (decision  386 ), the therapeutic temperature flag is set (step  388 ). If not, the therapeutic temperature flag is cleared (step  390 ). 
     In a similar manner to temperature, the system also determines if the pressure in the tubing  118  indicative of the pressure applied to the patient&#39;s eyelid is above the therapeutic pressure setting (decision  392 ). This is an indication that the pressure has risen to a level necessary to provide therapy and so that the therapy timer will accumulate in the run state  226 . The therapeuctic pressure setting is set by the system. Alternatively, it may be programmed by the user into the controller  72 . If the pressure level is above the therapeutic pressure setting (decision  392 ), the therapeutic pressure flag is set (step  394 ). If not, the therapeutic pressure flag is cleared (step  396 ). The system also checks to determine if the pressure level has increased to a minimum threshold level indicative of the force lever  86  being engaged by the user to allow therapy to start (decision  398 ). If so, the start flag is set (step  400 ). If not, the start flag is cleared (step  402 ). 
     The system also monitors the temperature thermistors  136 A,  136 B to determine if their measured signals track each other as an indication of whether the thermistors  136 A,  136 B may have malfunctioned (decision  404 ). Two thermistors are unlikely to produce the same output for a given temperature, but they change in like kind in response to the same conditions. If they are properly tracking each other, the alert flag is cleared indicating that no error condition exists for the thermistors (step  406 ). If not, an error message (e.g. “E_ 2 ”) may be displayed on the timer display  88  (step  408 ) before the alert flag is set (step  410 ). As previously discussed, the run state  226  checks the alert flag as a condition of allowing therapy to continue. The monitor state  228  continues to execute in a looping fashion until a condition occurs to place the controller  72  in the stop state  224 . 
       FIG. 26  illustrates the last state of the controller state machine, the stop state  224 . The stop state  224  is entered when the total therapy time has reached its preset maximum time or any error condition occurs (step  420 ). Once in the stop state  224 , the controller  72  cannot be restarted with the same disposable component  74  for safety reasons. The heating signal to the heating element  106  is disengaged to stop heat from being applied to the patient&#39;s eyelid (step  422 ). Further, the power supply to the heating element  106  can also be disabled as a further measure to ensure that heat will no longer be applied to the patient&#39;s eyelid (step  423 ). An optional test connector may be installed to download sensor or other operational data to memory for data logging or for testing. If installed (decision  424 ), the data may be downloaded to memory (step  426 ). Once the treatment data is downloaded, the controller  72  can check the status of the battery until the controller  72  is reset to enter the reset state  230  (see.  FIG. 21 ), since the controller  72  is not performing therapy and is otherwise dormant (decision  428 , step  430 ). If the test conenctor is not installed, the controller  72  continues to check for installation of the optional test connector as well as performing a battery level check (decision  425 , step  427 ) until either installed or the controller  72  is reset to enter the reset state  220  (see  FIG. 21 ). Thereafter, the system enters the run state  226 , in which case, therapy can begin again once the error conditions are eliminated and a new disposable component  74  is installed. 
       FIGS. 27-30  illustrate an alternative embodiment of the disposable component  74 B that may be employed by the present invention to apply heat and/or force to the patient&#39;s eyelid as part of treating MGD. As illustrated in  FIGS. 27 and 28 , the apparatus comprises an insulator  440  and a means for applying force to the eyelid  91 A,  91 B, or lens  440  In the most basic form, the insulator  440  is concave in shape and minors the curvature of the eyeball  442 , substantially similar to a contact lens. As employed herein, the term “insulator” is intended to include any component or material wherein there is greater resistance to thermal conduction or radiation towards the surface of the eye than towards the eyelid. Stated alternatively, in the insulator thermal energy radiates more easily towards the eyelid than towards the eyeball surface in order to minimize the possibility of causing injury to the eyeball  442 . In the model that was constructed, the diameter was sufficient to more than cover the cornea or in the approximate range of 15 mm to 25 mm would be sufficient for most eyes assuming a corneal relief zone of approximately 16 mm. It will be noted however, that the diameter of the insulator  440  can vary beyond the ranges stated above. 
     Further, the insulator  440  is constructed from a biocompatible material such as polymethylmethacrylate (PMMA), or in the case of the prototype that was constructed, epoxy or other materials well known to those skilled in the art. The insulator  440  may be flexible, but ideally should be only minimally compressible, as will become clear from the discussion that follows. According to the invention, the insulator  440  is inserted on the surface of the eye  442 , behind the rear surface of the eyelid and should include smooth edges so as not to scratch or cut either the eyelid or the eye. As used herein the term “eyelid” or “eyelids” is intended to include the upper lid and the lower lid, either in singly or in combination. The insulator  440  provides a back plate against which force may be applied. In limited circumstances when the obstruction in the meibomian gland channel is minimal, the meibomian gland may be cleared merely through the application of force externally applied to the eyelid, such as gentle finger press. More specifically, with the insulator  440  in place behind the eyelid, finger pressure is applied to the external surface of the eyelid, the eyelid being “sandwiched” between the finger and the insulator  440 . 
     In other instances, the meibomian gland obstruction may be blocked to a degree greater than can be treated with simple pressure alone. In such cases it is necessary to apply thermal energy to the eyelid in order to loosen, break up, fracture, soften or liquefy at least a portion of the occlusion. Thermal energy may be applied by any one of the well known means for applying thermal energy such as modalities such as resistive, IR (infrared), ultrasonic heating, microwave, any one of the numerous “hot pads” that chemically produce an exothermic reaction or in the simplest form a hot compress. Experimentation has revealed that in order to be clinically effective the eyelid should be heated to a temperature of between about 35 degrees Celsius and 47 degrees Celsius. The length of time for which thermal energy (i.e. heat) is applied to the eyelid depends upon the extent that the obstruction blocks the meibomian gland channel as well as the composition of the obstruction. In very minor cases, heat may be applied to the eyelid for less than three minutes or even as little as five to fifteen seconds. On the other hand, extreme blockage may require as much as thirty minutes of heating to melt, loosen, or soften the obstruction prior to the application of force to the eyelid to express the softened obstruction. Experimentation has further revealed that the eyelids are efficient heat exchangers with circulating blood acting as the cooling mechanism and that the eyelid temperature returns to normal in less than two minutes at which time the obstruction re-hardens making extraction difficult. It is therefore necessary to apply the aforesaid expressive force to the eyelid within that time frame in order for the treatment to be successful. Thus, gentle finger pressure, preferably in a milking type action, to urge the obstruction upward and out of the meibomian gland orifice should be employed. Again, depending on the nature and location of the obstruction, mere compressive force may be effective in some instances. 
     The insulator  440  is inserted between the rear of the eyelid on the surface of the eyeball  442 , as previously described. An eyecup  447  is employed to provide force and thus pressure to the eyelid. In one embodiment of the invention, thermal energy is applied as described above such as with a hot compress, and thereafter, within the one to two minute time frame, an eyecup (which may be unheated) is placed on the outer surfaces of the eyelid and force is applied thereto to express the softened obstruction. As illustrated, the eyecup mirrors the size and shape of the eyelids when closed. 
     In  FIGS. 29 and 30 , the insulator  440  is provided with a heater means or heater  448 . In this embodiment, the insulator  440  (e.g. lens) is concave in shape; however, the curvature is greater than that of the eyeball  442  so that an air pocket is formed between the insulator  440  and the eyeball  442 . The air pocket provides additional insulation to prevent the heat applied from being conducted to the eyeball  442  surface during the treatment time. Further, ends  450  of the insulator  440  will be the only portion that actually physically contacts the eyeball  442 . This section of the insulator  440  may be constructed of a biocompatible material that will not scrape or abrade the eyeball surface such as a soft rubber, plastic, or possibly even a soft metal. It will be noted that the lower surface  452  (i.e., that portion beneath the heater  448 ) and the upper surface  454  (i.e., that portion above heater  448 ) may be fabricated from different materials in order to minimize thermal conduction towards the eyeball and to facilitate thermal conduction towards the eyelid. One method of accomplishing the foregoing is to provide small air pockets in the lower surface  452  which would add additional insulation to that layer. 
     Heater  448  may be a resistive type heater, a thick film heater, or any one of a number of other types, such as a “flex circuit” (etched metal on flexible substrate) well known to those skilled in the art. As shown in  FIG. 30 , the insulator  440  is provided with a gripping means, handle, or platform  456  in which heater terminals  458  connect to the heater  448 , battery  460 , a thermal controller unit  462  (i.e. temperature regulator), and on/off switch  464  are located. The circuit comprising the heater  448 , a power source such as battery  460 , thermal controller unit  462 , and on/off switch  464  are connected in series. The thermal controller unit/thermal regulator  462  is selected so that the temperature may be capped at an upper temperature threshold, such as at 47 degrees Celsius for example. The thermal controller unit  462  may also be designed to and turn off the circuit when that temperature is exceeded in order to prevent damage to the eye and surrounding tissue. In an alternate embodiment, the heater  448  may be connected to an “off device” power source through the use of appropriately placed contacts  466  and  468  (see  FIG. 29 ). 
     Referring now back to the disposable component  74 B of  FIGS. 26-29 , a pair of opposing spaced apart cantilevered arms  470  extend perpendicularly outward from the outer surface of the insulator  440  and together with handle  456  define means for coupling the eyecup  447  to the insulator  440 . The respective arms  470  are tapered towards each other and each includes a notch  472  the purpose of which will become evident as the description proceeds. As best illustrated in  FIG. 6 , the heater  448  fits into a corresponding depression in the insulator  440  such that the two surfaces are flush in order to provide a smooth even surface for the inner eyelid to prevent rubbing and chaffing which upon blinking. Alternatively, the heater  448  could be embedded within insulator  440  or applied or connected to the surface thereof and with a smoothing coating overlay being added. 
     The eyecup  447  is adapted to overlie the outer surface of the eyelid, substantially conforms to the surface shape thereof and is adapted to cooperate with the insulator  440 . The eyecup  447  includes a centrally located longitudinal slot  474 . Positioned on above and below slot  474  and extending perpendicularly outward from the body of eyecup  447  is a pair of flexible spaced apart opposing cantilevered engagement arms  476  which include integrally molded finger grips or handles  478  and extensions  468 . Positioned on the underside of eyecup  447  is a pair of diaphragms  480 , which are in fluid communication with each other and which includes an inlet means or inlet  482 . The diaphragms  480  are attached to the eyecup  447  via conventional means, such as glue for example (not shown). Further, it will be noted from the drawings that there is sufficient space provided between the diaphragms  480  to permit the arms  470  to pass therethrough. 
     While not illustrated, it will be noted that the eyecup  447  could be provided with a single diaphragm  480  with a hole defining an opening through which the arms  470  may pass. The diaphragms  480  may be fabricated from a biocompatible material such as polyurethane foam (open or closed cell), a sealed air balloon, or a gell-filled bladder. Again, depending upon the type and degree of obstruction, the diaphragms will vary in thickness and/or durometer. In an alternate embodiment, the diaphragms  480  may comprise bladders which may be fabricated from any flexible, expandable material such as rubber or plastic. However, it is preferred that the coefficient of expansion be linear with respect to the amount of fluid added. The bladders  480  may be partially filled or inflated with a constant amount of fluid or they may be provided with a rudimentary pump connected to inlet  482  such as is used with a perfume aerosolizer. The fluid is preferably air, but may also be a liquid such as water, saline, etc. Further, while not shown, the fluid may also be heated in order to assist in the softening of any meibomian gland obstructions which may be present. It will be noted that for any given patient, either or both of the insulator and fluid may be heated as required in order to soften any given obstructed meibomian glands. 
     While not illustrated, the bladders  480  could be fabricated in such a manner that as they inflate, pressure is applied which urges the softened gland obstructive material up the gland channel and out of the gland orifice to clear the gland. One method would be to increase the thickness of the bladders  480  such that there is less resistance (less thickness) to inflation near the bottom of the gland and the resistance increases (greater thickness) as one reaches the gland orifice. 
     In operation, the insulator  440  is placed on the sclera of the eye  442  in much the same manner as a contact lens is inserted. When properly positioned, arms  470  will extend outward between the eyelids  91 A,  91 B. The eyecup  447  is then positioned with the concavity facing the eyelid  91 A,  91 B such that the notch ends of arms  470  are inserted into slot  474 . The eyecup  447  is directed along the arms  470  until notches  472  engage arm extensions  468  thus coupling the eyecup  447  to the insulator  440  and connecting contacts  466 ,  468 . The heater  448  is then activated by switch  446  or other means to which the heated fluid in bladders  480  may be added simultaneously or serially for the preselected period of time, for example, two minutes. Thereafter, or simultaneously with the application of heat, the bladders  480  may be expanded which will urge the softened meibomian gland sebum up and out of the gland channel towards the gland orifice, thus, unblocking the gland. When treatment is complete, finger grips  478 A,  478 B are then pressed towards each other so that the eyecup  447  is free to slide off of and be removed from the arms  470 . Thereafter, the insulator  440  is removed from the eyeball  442  and treatment is complete. 
     It will be noted that various mechanisms to lock the insulator to the eyecup could be employed, such as a ratchet type mechanism on arms  470  which is released upon compression of finger grips  478 A,  478 B, a press fit of the arms  470  into slot  474  as well as other mechanisms well known to those skilled in the art, not discussed herein. Manual control and release and force as well as manual adjustment of the eyecup may be employed during treatment and/or until expression of the obstruction or occlusion in the meibomian glands is achieved. While not specifically required, it is preferable that the locking mechanisms be near “zero insertion” force in order to minimize the potential for eye injury. Further, different eyecups with different shapes and different rigidities may be employed. Some of these alternate disposable components  74  are disclosed in  FIGS. 31-40  of the present application and will be discussed below. 
       FIGS. 31A and 31B  illustrate another alternative embodiment of the disposable component  74 C that may be employed by the present invention to apply heat and/or force to the patient&#39;s eyelid as part of treating MGD. In this embodiment, the lid warmer  90 C is firmly affixed to the eyecup  110 C without the ability to separate the two or make adjustments to change the distance between the lens  90 C and the eyecup  110 C. The only moveable component is an inflatable bladder  114 C that is controlled to apply a force to the outside of the patient&#39;s eyelid. Such a disposable component  74 C may be employed as simpler to install and use by technicians during therapy since no adjustments to the position of the eyecup  110 C with respect to the lid warmer  90 C are necessary. 
     The disposable component  74 C comprises a lid warmer  90 C in the form of a lens similar to previously discussed lid warmer  90 A,  90 B. The lid warmer  90 C contains a heating element (not shown) to apply heat to the inside of the patient&#39;s eyelid when the inside surface of the lens  93 C is placed on top of the patient&#39;s eye. The lid warmer  90 C also contains a lid warmer platform  94 C to allow a technician or doctor to grasp the lid warmer  90 C and install it over top of the patient&#39;s eye. An eyecup  110 C is also provided to apply force to the outside of the patient&#39;s eyelid. The eyecup  110 C is formed by an upper and lower concave cups  471 A,  471 B. An opening  473  is provided between the two cups  471 A,  471 B about a horizontal center line of the lens  90 C for ease in making adjustments and because the meibomian glands are located above and below the center of the lens. Thus, it may not be necessary to apply force in the center of the eyecup  110 C where the upper and lower eyelids of the patient meet together when the disposable component  74 C is installed. The lid warmer platform  94  is securely fixed to the eyecup  110 C at an interface section  475  to provide a fixed distance between the inside of the eyecup  110 C and the outside surface of the lens  92 C 
       FIG. 32  illustrates another alternative embodiment of the disposable component  74 D that may be employed by the present invention to apply heat and/or force to the patient&#39;s eyelid as part of treating MGD. In this embodiment, the eyecup  110 D contains a latching mechanism  116 D that allows the eyecup  110 D to be affixed to the lid warmer platform  94 D and the distance between an inflatable bladder  479 A,  479 B and the outside surface of the lens  92 D to be adjusted. 
     In this embodiment, the eyecup  110 D design contains split upper and lower eyecups  481 A,  481 B similar to the eyecup  110 C design illustrated in  FIG. 31 , except that the eyecups  481 A,  481 B that support membranes or bladders  479 A,  479 B to apply force to the patient&#39;s eyelid are completely separated from each other. The split eyecups  481 A,  481 B allow the upper eyecup  481 A to be lifted independent of the lower eyecup  481 B to be able to release the eyecup  110 D from the lid warmer  94 D. In this regard, the lid warmer platform  94 D contains holders  483  that are adapted to secure an eyecup platform  485  attached to the eyecup  110 D to secure the eyecup  110 D to the lid warmer  94 D. The eyecup platform  485  contains a clamp  484 A hingedly attached to the lid warmer platform  94 D via hinge  487 . The lid warmer platform  94 D contains an opposing clamp  484 B, such that when the clamps  484 A and  484 B are squeezed together, the eyecup platform  485  is released from the holders  483  to release the eyecup  110 D from the lid warmer  94 D. The lid warmer platform  94 D also contains a grip handle  493  that can be held while the clamps  484 A,  484 B are squeezed to hold the lid warmer  94 D when the eyecup  110 D is released. 
       FIG. 33  illustrates another alternative embodiment of the disposable component  74 E that may be employed by the present invention to apply heat and/or force to the patient&#39;s eyelid as part of treating MGD. This embodiment is similar to the disposable component  74 E of  FIG. 32 , except that the latching mechanism  116 E to attach and release the eyecup  110 E from the lid warmer  90 E is provided completely as part of the eyecup  110 E. The latching mechanism  116 E allows the eyecup  110 F to be affixed to the lid warmer platform  94 E and the distance between an inflatable bladder  490 A,  490 B and the outside surface of the lens  92 E to be adjusted. 
     In this embodiment, the eyecup  110 E design contains a split upper and lower eyecups  491 A,  491 B similar to the eyecup  110 E design illustrated in  FIG. 32 . The upper and lower eyecups  491 A,  491 B support membranes  490 A,  490 B that apply force to the patient&#39;s eyelid. Eyecup platforms  492 ,  496  extend from the eyecup  110 E and contain clamps  494 A,  494 B hingedly attached to each other via hinge  493 . When the clamps  494 A and  494 B are squeezed together, the eyecup platforms  492 ,  496  move away from each other to release the lid warmer platform  94 E. The lid warmer platform  94 E was compressed between the eyecup platforms  492 ,  496  when the clamps  494 A,  494 B were not being squeezed to secure the lid warmer  90 E to the eyecup  110 E. The eyecup  110 E can be adjusted with respect to the lid warmer  90 E by compressing the clamps  494 A and  494 B and moving the eyecup platforms  492 ,  496  to the desired location on the lid warmer platform  94 E. The lid warmer platform  94 E may also contain a grip  489  at its end to provide better gripping of the lid warmer platform  94 E when the eyecup  110 E is adjustably placed at the desired location along the lid warmer platform  94 E. 
       FIG. 34  illustrates another alternative embodiment of the disposable component  74 F that may be employed by the present invention to apply heat and/or force to the patient&#39;s eyelid as part of treating MGD. This embodiment has a latching mechanism  116 F similar to the disposable component  74 E of  FIG. 33 , except that the eyecup  110 F is one piece having an eyecup  504  that does not contain separable components. The latching mechanism  116 F allows the eyecup  110 F to be affixed to the lid warmer platform  94 F and the distance between an inflatable bladder  502 ,  490 B and the outside surface of the lens  92 F to be adjusted. The eyecup  110 F contains a pneumatic interface  508  to allow the controller  72  to inflate the bladder  502 . 
     The eyecup  110 F also contains an eyecup platform  510  that supports the latching mechanism  116 F. The eyecup platform  510  supports eyecups  504 A,  504 B that support a membrane or bladder  502  to apply force to the patient&#39;s eyelid. The latching mechanism  116 F is comprised of eyecup clamps  512 A,  512 B that are hingedly attached to each other via hinge  513 . When the clamps  512 A and  512 B are squeezed together, an orifice  514  in the eyecup platform  510 I is unlocked to allow the lid warmer platform  94 F to be moved transversely along the eyecup platform  510 F. In this manner, the lid warmer  94 F can be affixed to the eyecup  110 F and moved to the desired distance from the eyecup  110 F. If the lid warmer  90 F and its platform  94 F are pulled away from the eyecup  110 F, the lid warmer  90 F can be released from the eyecup  110 F when platform  94 F is pulled through the orifice  514 . Just as the platform  94 F in  FIG. 33 , the lid warmer platform  94 E may also contain a grip  500  at its end to provide better gripping of the lid warmer platform  94 F when the eyecup  110 F is adjustably placed at the desired location along the lid warmer platform  94 F. 
       FIG. 35  illustrates another alternative embodiment of the disposable component  74 G that may be employed by the present invention to apply heat and/or force to the patient&#39;s eyelid as part of treating MGD. This embodiment has a latching mechanism  116 G that operates similar to the manner in which a syringe works. The eyecup  110 G is formed from one piece. An outer surface of the eyecup  522  is attached to a cylindrically-shaped tube  524  having a platform  526  on its end. The lid warmer platform  94 G extends through the tube  524  and an orifice  528  through the platform  526  and contains a lid warmer platform  94 G in the form of a plunger  520  on its end that rests against the platform  524  when fully pushed down or engaged. To move the eyecup  90 G farthest from the lid warmer  90 G, the plunger  520  is fully engaged forward or downward. To move the lid warmer  90 G closer to the eyecup  110 G, the plunger  520  is pulled upward or backwards. The plunger  520  controls the movement of the lid warmer  90 G and thus the distance between the lid warmer  90 G and the eyecup  110 G to administer therapy. 
       FIGS. 36A and 36B  illustrate another alternative embodiment of the disposable component  74 H that may be employed by the present invention to apply heat and/or force to the patient&#39;s eyelid as part of treating MGD. This embodiment is similar to the disposable component  74 E of  FIG. 33  in that separate upper and lower eyecups  530 A,  530 B are provided to apply force to the upper and lower eyelid of the patient. However, both eyecups  530 A,  530 B do not have to be engaged. Each can be engaged separately. For example, it may be desired to treat the meibomian glands in only the upper or lower eyelid of a patient and not both at the same time. In this manner, the lid warmer platform  94 H contains a hinge  534 . The upper and lower eyecups  530 A,  530 B are attached to the hinge  534  such that they can rotate over the lid warmer platform  94 H. When not in use, the eyecups  580 A,  580 B can be rotated away from the lid warmer platform  94 H as illustrated in  FIG. 36A . The lid warmer platform  94 E contains a grooved surface  531  that allows the eyecups  530 A,  530 B to be rotated about hinge  534  and moved to the outside surface of the lens  92 H as illustrated in  FIG. 36B . When in use, the eyecups  580 A,  580 B move past a notch  533  in the lid warmer platform  94 H to lock in place. 
       FIG. 37  illustrates another alternative embodiment of the disposable component  74 I that may be employed by the present invention to apply heat and/or force to the patient&#39;s eyelid as part of treating MGD. In this embodiment, the eyecup  110 I is formed by eyecup  540  that supports a membrane or bladder  541  to apply force to the patient&#39;s eyelid. The eyecup  540  contains an opening  542  through the lid warmer platform  94 I and extends through to attach the eyecup  110 I to the lid warmer platform  94 I when the disposable component  74 I is installed. The lid warmer platform  94 I contains a thickened surface  543  which locks the lid warmer platform  94 I into the split  542  and prevents the eyecup  110 I from moving about the lid warmer platform  94 I for a secure fit when in use. A handle  544  is also attached to the eyecup  540  to allow a technician to hold the eyecup  540  when adjusting the lid warmer  90 I with respect to the eyecup  540 . 
       FIGS. 38A and 38B  illustrate another alternative embodiment of the disposable component  74 J that may be employed by the present invention to apply heat and/or force to the patient&#39;s eyelid as part of treating MGD. In this embodiment, the eyecup  110 J is provided as one piece. The eyecup  110 J supports a membrane or bladder  551  to apply force to a patient&#39;s eyelid and contains a ridge  552  through which an orifice  554  protrudes through. A bladder advance mechanism  554  is placed through the orifice  554 , wherein the lid warmer platform  94 J extends through th orifice  554  in the bladder advance mechanism  556 . The bladder (not shown) is attached to the bladder advance mechanism  556 . When it is desired to advance the bladder (not shown) to the patient&#39;s eyelid to apply force, the bladder advance mechanism  556  is rotated such that notch  558  can fit inside a groove  557  on the ridge  552  to allow the bladder advance mechanism  556  to move forward through the orifice  552  towards the lid warmer  90 J and lock in place. When desired to move the bladder away from the lid warmer  90 J, the bladder advance mechanism  556  is pulled back so that the notch  558  is removed from the groove  557  and can be rotated away from the groove  557  to be supported by the ridge  552 . 
       FIG. 39  illustrates another alternative embodiment of the disposable component  74 K that may be employed by the present invention to apply heat and/or force to the patient&#39;s eyelid as part of treating MGD. In this embodiment, the eyecup  110 K is provided as one piece. The eyecup  110 K supports a membrane or bladder  561  that applies force to the patient&#39;s eyelid. The eyecup  110 K contains an outer surface  560  that contains rib structures  562 A,  562 B to support an orifice chamber  564  having an orifice  566  through which the lid warmer platform  94 K extends to attach the eyecup  110 K to the lid warmer  90 K. Squeezable eyecup platforms  568 ,  570  are attached on each side of the orifice  566  to the rib structures  562 A,  562 B on one end and to a common hinge  572  on their other end. When the eyecup platforms  568 ,  570  are squeezed, it allows the lid warmer platform  94 K to be move transversally through the orifice  566 . When the eyecup  110 K is to be placed against the patient&#39;s eyelid, a grip  578  is pulled such that a neck  576  of the lid warmer platform  94 K is inserted and locked down into a groove  574  formed in the lower eyecup platform  570 . 
       FIG. 40  illustrates another alternative embodiment of the disposable component  74 L that may be employed by the present invention to apply heat and/or force to the patient&#39;s eyelid as part of treating MGD. In this embodiment, the eyecup  110 L and lid warmer  94 L are provided as two separate pieces. Finger tabs  588 A,  588 B, attached to hinge  590 , can be depressed to allow room for an opening  482  in the eyecup  110 L to be inserted over top the lid warmer platform  94 L along opening  582  in the eyecup  580  where desired. When the eyecup  110 L is placed on the lid warmer platform  94 L in the desired location, the finger tabs  588 A,  558 B are released and the tabs  588 A,  588 B position and hold the eyecup  110 L in place. 
     Although the present application discusses and provides devices for applying heat on the inside of the eyelid and force to the outside of the eyelid to treat MGD, other configurations are possible. Heat and force may be applied in a number of different combinations and manners to treat MGD. For example,  FIG. 41  illustrates an alternative embodiment of the present invention for applying heat and force to tissue proximate a patient&#39;s meibomian gland to treat MGD. In this embodiment, heat is applied and force is applied. Heat is applied provide conductive heat transfer to the meibomian glands to the desired temperature level (step  600 ). For example, heat may be applied to raise the temperature at the inside of the eyelid between 43-47 degrees Celsius. The heat may also be regulated, meaning that a heating means or element is controlled to be within the temperatures and means that are safe for the eyelid and at a sufficient temperature for melting, loosening, or softening an occlusion or obstruction in the meibomian gland. 
     A force may also be applied to tissue proximate the patient&#39;s meibomian gland to increase the efficiency of heat transfer. As previously described, the application of force towards the heat source with the patient&#39;s eyelid “sandwiched” therebetween provides greater surface contact between the heat source and the eyelid for more efficient conductive heat transfer. Further, the application of force reduces blood flow in the eyelids to reduce convective heat loss through the eyelids and allow the temperature at the meibomian glands to not only rise to higher levels, but do so more quickly and efficiently (step  602 ). 
     The heat and/or force may be maintained for a period of time sufficient to raise the temperature at the meibomian glands sufficient to melt, loosen, or soften the obstructions or occlusions (step  604 ). The force may be maintained after heat is removed, or vice versa depending on the treatment technique desired. Maintaining force after heat is removed may reduce convective heat loss at the meibomian glands and thus keep the temperature level at the meibomian glands to the therapeutic levels for more time than if the force was removed. Maintaining heat without maintaining force may be employed to allow blood flow in the eyelids, such as between successive treatments. For example, it may be desirable to maintain heat to lessen the total amount of treatment time while applying and removing force between treatments. Also, it may not be necessary to apply significant amounts of force, or for the same duration as application of heat, if the obstruction or occlusion is located in close proximity to the lid margin rather than in the deeper portions of the meibomian gland. Thereafter, either during heating and/or the application of force or after either, obstructions or occlusions in the meibomian glands may be expressed so that sebum flow is restored from the glands to establish a sufficient lipid layer (step  606 ). 
     The force may be regulated, meaning that a force generating means is controlled to be within the pressure ranges that are safe to be applied to tissue proximate the meibomian glands and at sufficient pressure to allow the temperature at the meibomian gland to be raised sufficiently. The force may be applied during heating, after heating, or both during and after heating. In either case, the force may assist in expressing occlusions or obstructions when in a loosened, softened, or melted state from the meibomian glands. The force may include vibratory type forces, including those generated mechanically or using fluid type devices or mechanisms. The level of force needed to express obstructions or occlusions in the glands may be greatly reduced when heat is applied to the obstructions or occlusions to place them in a melted, softened, or loosened state. 
     The application of force can also stimulate the movement of fluids or suspensions of occlusions or obstructions from the glands. The present invention can be used with devices which generally apply a regulated force or milking action to the eyelid to express the fluids or suspensions or to otherwise mechanically stimulate the movement of fluids from the glands. In some instances, a small, gentle, continuous force applied to the eyelid will assist in expression of the fluids and suspensions. Vibration can also be used when applying force simultaneously or immediately after the heating to further assist in the expression. 
     Any device may be employed to generate heat on the outside of the patient&#39;s eyelid, including those described herein. Other devices may be employed, such as the apparatus disclosed in U.S. Patent Application Publication No. 2007/1016254, entitled “Method and apparatus for treating gland dysfunction employing heated medium,” and incorporated herein by reference in its entirety. In this application, an apparatus is employed to apply heat to the outside of the patient&#39;s eyelid via heated fluid transfer. Further, a gas may be employed as opposed to fluid to apply heat to the patient&#39;s eyelid. 
     Just as discussed above in the flowchart of  FIG. 6 , where only heat is applied, regulated heat can include controlling heat according to a temperature profile. The temperature profile may be a constant temperature, include ramp-ups, ramp-downs, peaks and valleys. Further, the temperature profile may include heat pulses or be modulated with various characteristics, including the use of pulse width modulation (PWM) techniques. The use of modulated heat may allow the temperature to be raised even higher at the eyelid without damage to the patient&#39;s eyelid since the increased temperatures are applied for shorter periods of time. Obstructions or occlusions in the meibomian glands may have melting, loosening, or softening points that are beyond temperatures that may be applied without the use of modulated heat. The temperature needed to melt, loosen, or soften obstructions or occlusions may depend on how keratinized the obstruction or occlusion is. Not all obstructions or occlusions have the same melting, loosening, or softening points. By example only, elevated temperatures between 47 and 55 degrees Celsius may be possible when applying modulated heat, especially if the eyelid has been anesthetized. 
     The regulated heat can be maintained at a therapeutic temperature for a treatment period. The treatment period can be approximately 1 to 10 minutes for example, since the application of force may reduce the amount of time it takes for the heat source to raise the temperature at the meibomian glands to the desired level. The heat could also be repeatedly applied and maintained for a desired period of time to keep the occlusion or obstruction in a melted, loosened, or softened state. Either during or after such treatment by regulated heat, mechanical expression of lipids and other fluids from the meibomian glands has been found to clear obstructions which have essentially melted or been placed in a suspension state (by virtue of melting materials binding solids together). 
     Optionally, after expression of the occlusions or obstructions is performed (step  606 ), an optional pharmacological agent may be applied to the meibomian gland to promote the free flow of sebum and/or reduce or prevent inflammation or infections of the eye or eyelids (step  608 ). The previous discussion in the flowcharts of  FIGS. 6 and 8  regarding use of pharmacological agents above is equally applicable for this embodiment and thus will not be repeated here. Those compounds are illustrative examples of appropriate pharmacological agents, but those skilled in the art will appreciate that other pharmacological compounds may be utilized. 
       FIG. 42  illustrates an alternative embodiment of the present invention for applying heat and force to a patient&#39;s eyelid to treat MGD. In this embodiment, heat is applied to the outside of the eyelid and force is applied to the inside of the eyelid. Heat is applied to the outside of the eyelid to provide conductive heat transfer to the meibomian glands to the desired temperature level (step  610 ). For example, heat may be applied to raise the temperature at the inside of the eyelid to between 43-47 degrees Celsius. The heat may also be regulated, meaning that a heating means or element is controlled to be within the temperatures and means that are safe for the eyelid and at a sufficient temperature for melting, loosening, or softening an occlusion or obstruction in the meibomian gland. 
     A force may also be applied to the inside of the eyelid to increase the efficiency of heat transfer. As previously described, the application of force towards the heat source with the patient&#39;s eyelid “sandwiched” therebetween provides greater surface contact between the heat source and the eyelid for more efficient conductive heat transfer. Further, the application of force reduces blood flow in the eyelids to reduce convective heat loss through the eyelids and allow the temperature at the meibomian glands to not only rise to higher levels, but do so more quickly and efficiently (step  612 ). 
     The heat and/or force may be maintained for a period of time sufficient to raise the temperature at the meibomian glands to a level sufficient to melt, loosen, or soften the obstructions or occlusions (step  614 ). The force may be maintained after heat is removed, or vice versa depending on the treatment technique desired. Maintaining force after heat is removed may reduce convective heat loss at the meibomian glands and thus keep the temperature level at the meibomian glands to the therapeutic levels for more time than if the force was removed. Maintaining heat without maintaining force may be employed to allow blood flow in the eyelids, such as between successive treatments. For example, it may be desirable to maintain heat to lessen the total amount of treatment time while applying and removing force between treatments. Also, it may not be necessary to apply significant amounts of force, or for the same duration as application of heat, if the obstruction or occlusion is located in close proximity to the lid margin rather than in the deeper portions of the meibomian gland. Thereafter, either during heating and/or the application of force or after either, obstructions or occlusions in the meibomian glands may be expressed so that sebum flow is restored from the glands to establish a sufficient lipid layer (step  616 ). 
     The force may be regulated, meaning that a force generating means is controlled to be within the pressure ranges that are safe to be applied to the eyelid and at sufficient pressure to allow the temperature at the meibomian gland to be raised sufficiently. The force may be applied during heating, after heating, or both during and after heating. In either case, the force may assist in expressing occlusions or obstructions when in a loosened, softened, or melted state from the meibomian glands. The force may include vibratory type forces, including those generated mechanically or using fluid type devices or mechanisms. The level of force needed to express obstructions or occlusions in the glands may be greatly reduced when heat is applied to the obstructions or occlusions to place them in a melted, softened, or loosened state. 
     The application of force can also stimulate the movement of fluids or suspensions of occlusions or obstructions from the glands. The present invention can be used with devices which generally apply a regulated force or milking action to the eyelid to express the fluids or suspensions or to otherwise mechanically stimulate the movement of fluids from the glands. In some instances, a small, gentle, continuous force applied to the eyelid will assist in expression of the fluids and suspensions. Vibration can also be used when applying force simultaneously or immediately after the heating to further assist in the expression. 
     Any device may be employed to generate heat on the outside of the patient&#39;s eyelid, including those described herein. Other devices may be employed, such as the apparatus disclosed in U.S. Patent Application Publication No. 2007/1016254, entitled “Method and apparatus for treating gland dysfunction employing heated medium,” and incorporated herein by reference in its entirety. In this application, an apparatus is employed to apply heat to the outside of the patient&#39;s eyelid via heated fluid transfer. Further, a gas may be employed as opposed to fluid to apply heat to the patient&#39;s eyelid. 
     Just as discussed above in the flowchart of  FIG. 6 , where only heat is applied, regulated heat can include controlling heat according to a temperature profile. The temperature profile may be a constant temperature, include ramp-ups, ramp-downs, peaks and valleys. Further, the temperature profile may include heat pulses or be modulated with various characteristics, including the use of pulse width modulation (PWM) techniques. The use of modulated heat may allow the temperature to be raised even higher at the eyelid without damage to the patient&#39;s eyelid since the increased temperatures are applied for shorter periods of time. Obstructions or occlusions in the meibomian glands may have melting, loosening, or softening points that are beyond temperatures that may be applied without the use of modulated heat. The temperature needed to melt, loosen, or soften obstructions or occlusions may depend on how keratinized the obstruction or occlusion is. Not all obstructions or occlusions have the same melting, loosening, or softening points. By example only, elevated temperatures between 47 and 55 degrees Celsius may be possible when applying modulated heat, especially if the eyelid has been anesthetized. 
     The regulated heat can be maintained at a therapeutic temperature for a treatment period. The treatment period can be approximately 1 to 10 minutes for example, since the application of force may reduce the amount of time it takes for the heat source to raise the temperature at the meibomian glands to the desired level. The heat could also be repeatedly applied and maintained for a desired period of time to keep the occlusion or obstruction in a melted, loosened, or softened state. Either during or after such treatment by regulated heat, mechanical expression of lipids and other fluids from the meibomian glands has been found to clear obstructions which have essentially melted or been placed in a suspension state (by virtue of melting materials binding solids together). 
     Optionally, after expression of occlusions or obstructions is performed (step  616 ), an optional pharmacological agent may be applied to the meibomian gland to promote the free flow of sebum and/or reduce or prevent inflammation or infections of the eye or eyelids (step  618 ). The previous discussion in the flowcharts of  FIGS. 6 and 8  regarding use of pharmacological agents above is equally applicable for this embodiment and thus will not be repeated here. Those compounds are illustrative examples of appropriate pharmacological agents, but those skilled in the art will appreciate that other pharmacological compounds may be utilized. 
       FIG. 43  illustrates an alternative embodiment of the present invention for applying heat and force to a patient&#39;s eyelid to treat MGD. In this embodiment, heat and force are both applied to the outside of the eyelid. Heat is applied to the outside of the eyelid to provide conductive heat transfer to the meibomian glands to the desired temperature level (step  620 ). For example, heat may be applied to raise the temperature at the inside of the eyelid between 43-47 degrees Celsius. The heat may also be regulated, meaning that a heating means or element is controlled to be within the temperatures and means that are safe for the eyelid and at a sufficient temperature for melting, loosening, or softening an occlusion or obstruction in the meibomian gland. 
     A force may also be applied to the outside of the eyelid to increase the efficiency of heat transfer. As previously described, the application of force may provide greater surface contact between the heat source and the eyelid for more efficient conductive heat transfer. Further, the application of force reduces blood flow in the eyelids to reduce convective heat loss through the eyelids and allow the temperature at the meibomian glands to not only rise to higher levels, but do so more quickly and efficiently (step  622 ). 
     The heat and/or force may be maintained for a period of time sufficient to raise the temperature at the meibomian glands sufficient to melt, loosen, or soften the obstructions or occlusions (step  624 ). The force may be maintained after heat is removed, or vice versa depending on the treatment technique desired. Maintaining force after heat is removed may reduce convective heat loss at the meibomian glands and thus keep the temperature level at the meibomian glands to the therapeutic levels for more time than if the force was removed. Maintaining heat without maintaining force may be employed to allow blood flow in the eyelids, such as between successive treatments. For example, it may be desirable to maintain heat to lessen the total amount of treatment time while applying and removing force between treatments. Also, it may not be necessary to apply significant amounts of force, or for the same duration as application of heat, if the obstruction or occlusion is located in close proximity to the lid margin rather than in the deeper portions of the meibomian gland. Thereafter, either during heating and/or the application of force or after either, obstructions or occlusions in the meibomian glands may be expressed so that sebum flow is restored from the glands to establish a sufficient lipid layer (step  626 ). 
     The force may be regulated, meaning that a force generating means is controlled to be within the pressure ranges that are safe to be applied to the eyelid and at sufficient pressure to allow the temperature at the meibomian gland to be raised sufficiently. The force may be applied during heating, after heating, or both during and after heating. In either case, the force may assist in expressing occlusions or obstructions when in a loosened, softened, or melted state from the meibomian glands. The force may include vibratory type forces, including those generated mechanically or using fluid type devices or mechanisms. The level of force needed to express obstructions or occlusions in the glands may be greatly reduced when heat is applied to the obstructions or occlusions to place them in a melted, softened, or loosened state. 
     The application of force can also stimulate the movement of fluids or suspensions of occlusions or obstructions from the glands. The present invention can be used with devices which generally apply a regulated force or milking action to the eyelid to express the fluids or suspensions or to otherwise mechanically stimulate the movement of fluids from the glands. In some instances, a small, gentle, continuous force applied to the eyelid will assist in expression of the fluids and suspensions. Vibration can also be used when applying force simultaneously or immediately after the heating to further assist in the expression. 
     Any device may be employed to generate heat on the outside of the patient&#39;s eyelid, including those described herein. Other devices may be employed, such as the apparatus disclosed in U.S. Patent Application Publication No. 2007/1016254, entitled “Method and apparatus for treating gland dysfunction employing heated medium,” and incorporated herein by reference in its entirety. In this application, an apparatus is employed to apply heat to the outside of the patient&#39;s eyelid via heated fluid transfer. Further, a gas may be employed as opposed to fluid to apply heat to the patient&#39;s eyelid. 
     Just as discussed above in the flowchart of  FIG. 6 , where only heat is applied, regulated heat can include controlling heat according to a temperature profile. The temperature profile may be a constant temperature, include ramp-ups, ramp-downs, peaks and valleys. Further, the temperature profile may include heat pulses or be modulated with various characteristics, including the use of pulse width modulation (PWM) techniques. The use of modulated heat may allow the temperature to be raised even higher at the eyelid without damage to the patient&#39;s eyelid since the increased temperatures are applied for shorter periods of time. Obstructions or occlusions in the meibomian glands may have melting, loosening, or softening points that are beyond temperatures that may be applied without the use of modulated heat. The temperature needed to melt, loosen, or soften obstructions or occlusions may depend on how keratinized the obstruction or occlusion is. Not all obstructions or occlusions have the same melting, loosening, or softening points. By example only, elevated temperatures between 47 and 55 degrees Celsius may be possible when applying modulated heat, especially if the eyelid has been anesthetized. 
     The regulated heat can be maintained at a therapeutic temperature for a treatment period. The treatment period can be approximately 1 to 10 minutes for example, since the application of force may reduce the amount of time it takes for the heat source to raise the temperature at the meibomian glands to the desired level. The heat could also be repeatedly applied and maintained for a desired period of time to keep the occlusion or obstruction in a melted, loosened, or softened state. Either during or after such treatment by regulated heat, mechanical expression of lipids and other fluids from the meibomian glands has been found to clear obstructions which have essentially melted or been placed in a suspension state (by virtue of melting materials binding solids together). 
     Optionally, after expression of occlusions or obstructions is performed (step  626 ), an optional pharmacological agent may be applied to the meibomian gland to promote the free flow of sebum and/or reduce or prevent inflammation or infections of the eye or eyelids (step  628 ). The previous discussion in the flowcharts of  FIGS. 6 and 8  regarding use of pharmacological agents above is equally applicable for this embodiment and thus will not be repeated here. Those compounds are illustrative examples of appropriate pharmacological agents, but those skilled in the art will appreciate that other pharmacological compounds may be utilized. 
       FIG. 44  illustrates an alternative embodiment of the present invention for applying heat and force to a patient&#39;s eyelid to treat MGD. In this embodiment, heat is applied to both the inner and external surface of the patient&#39;s eyelid. Force may also be applied to the patient&#39;s eyelid. Heat is applied to the both the inside and outside of the eyelid to provide even more efficient conductive heat transfer to the meibomian glands to the desired temperature level (step  630 ). For example, heat may be applied to raise the temperature at the inside of the eyelid between 43-47 degrees Celsius. The heat may also be regulated, meaning that a heating means or element is controlled to be within the temperatures and means that are safe for the eyelid and at a sufficient temperature for melting, loosening, or softening an occlusion or obstruction in the meibomian gland. 
     A force may also be applied to the eyelid to increase the efficiency of heat transfer. As previously described, the application of force may provide greater surface contact between the heat source and the eyelid for more efficient conductive heat transfer. Further, the application of force reduces blood flow in the eyelids to reduce convective heat loss through the eyelids and allow the temperature at the meibomian glands to not only rise to higher levels, but do so more quickly and efficiently (step  632 ). 
     The heat and/or force may be maintained for a period of time sufficient to raise the temperature at the meibomian glands sufficient to melt, loosen, or soften the obstructions or occlusions (step  634 ). The force may be maintained after heat is removed, or vice versa depending on the treatment technique desired. Maintaining force after heat is removed may reduce convective heat loss at the meibomian glands and thus keep the temperature level at the meibomian glands to the therapeutic levels for more time than if the force was removed. Maintaining heat without maintaining force may be employed to allow blood flow in the eyelids, such as between successive treatments. For example, it may be desirable to maintain heat to lessen the total amount of treatment time while applying and removing force between treatments. Also, it may not be necessary to apply significant amounts of force, or for the same duration as application of heat, if the obstruction or occlusion is located in close proximity to the lid margin rather than in the deeper portions of the meibomian gland. Thereafter, either during heating and/or the application of force or after either, obstructions or occlusions in the meibomian glands may be expressed so that sebum flow is restored from the glands to establish a sufficient lipid layer (step  636 ). 
     The force may be regulated, meaning that a force generating means is controlled to be within the pressure ranges that are safe to be applied to the eyelid and at sufficient pressure to allow the temperature at the meibomian gland to be raised sufficiently. The force may be applied during heating, after heating, or both during and after heating. In either case, the force may assist in expressing occlusions or obstructions when in a loosened, softened, or melted state from the meibomian glands. The force may include vibratory type forces, including mechanical or those using fluid type devices or mechanisms. The level of force needed to express obstructions or occlusions in the glands may be greatly reduced when heat is applied to the obstructions or occlusions to place them in a melted, softened, or loosened state. 
     The application of force can also stimulate the movement of fluids or suspensions of occlusions or obstructions from the glands. The present invention can be used with devices which generally apply a regulated force or milking action to the eyelid to express the fluids or suspensions or to otherwise mechanically stimulate the movement of fluids from the glands. In some instances, a small, gentle, continuous force applied to the eyelid will assist in expression of the fluids and suspensions. Vibration can also be used when applying force simultaneously or immediately after the heating to further assist in the expression. 
     Any device may be employed to generate heat on the inside and outside of the patient&#39;s eyelid, including those described herein. Just as discussed above in the flowchart of  FIG. 6 , where only heat is applied, regulated heat can include controlling heat according to a temperature profile. The temperature profile may be a constant temperature, include ramp-ups, ramp-downs, peaks and valleys. Further, the temperature profile may include heat pulses or be modulated with various characteristics, including the use of pulse width modulation (PWM) techniques. The use of modulated heat may allow the temperature to be raised even higher at the eyelid without damage to the patient&#39;s eyelid since the increased temperatures are applied for shorter periods of time. Obstructions or occlusions in the meibomian glands may have melting, loosening, or softening points that are beyond temperatures that may be applied without the use of modulated heat. The temperature needed to melt, loosen, or soften obstructions or occlusions may depend on how keratinized the obstruction or occlusion is. Not all obstructions or occlusions have the same melting, loosening, or softening points. By example only, elevated temperatures between 47 and 55 degrees Celsius may be possible when applying modulated heat, especially if the eyelid has been anesthetized. 
     The regulated heat can be maintained at a therapeutic temperature for a treatment period. The treatment period can be approximately 1 to 10 minutes for example, since the application of force may reduce the amount of time it takes for the heat source to raise the temperature at the meibomian glands to the desired level. The heat could also be repeatedly applied and maintained for a desired period of time to keep the occlusion or obstruction in a melted, loosened, or softened state. Either during or after such treatment by regulated heat, mechanical expression of lipids and other fluids from the meibomian glands has been found to clear obstructions which have essentially melted or been placed in a suspension state (by virtue of melting materials binding solids together). 
     Optionally, after expression of occlusions or obstructions is performed (step  636 ), an optional pharmacological agent may be applied to the meibomian gland to promote the free flow of sebum and/or reduce or prevent inflammation or infections of the eye or eyelids (step  638 ). The previous discussion in the flowcharts of  FIGS. 6 and 8  regarding use of pharmacological agents above is equally applicable for this embodiment and thus will not be repeated here. Those compounds are illustrative examples of appropriate pharmacological agents, but those skilled in the art will appreciate that other pharmacological compounds may be utilized. 
     Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present invention. Heat as used in this application can mean the application of thermal energy. Heat may be applied to the patient&#39;s eyelid, related structure, or surrounding tissue using any type of thermal energy. Force may be applied to the patent&#39;s eyelid to apply pressure to the patient&#39;s eyelid, related structure, and/or surrounding tissue using any type of force or force generating means or device. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.