Patent Publication Number: US-2022218514-A1

Title: Ophthalmic devices, systems and methods for treating dry eye

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to ophthalmic devices for treating dry eye, and, in particular but not exclusively, relates to ophthalmic devices for treating dry eye through heating Meibomian glands and/or cooling a surface of the eye. 
     BACKGROUND 
     Dry eye disease is one of the most common eye conditions worldwide. Many dry eye cases are related to the absence of, or severely reduced production of, meibum, an oily substance produced by the Meibomian (also expressed as meibomian) glands. There are Meibomian glands located in the upper and lower eyelids, and lipids are a major component of meibum. One of the root causes of the lack of meibum are Meibomian glands that become completely or partially clogged. Lack of meibum production and secretion are some symptoms of Meibomian gland dysfunction. 
     Many dry eye cases are also related to lack of tear production or tears that evaporate too quickly. 
     Normally, the lipid layer produced by the Meibomian glands spreads evenly into a thin protective film over the air-tear interface above the cornea. Every time a person blinks a slight amount of lipid protective film is spread. However, there are many conditions under which this oily layer no longer spreads out evenly over the tear film and this process can be interrupted, reduced, or even stopped entirely, including inadequate blinking from excessive screen time known as computer vision syndrome. 
     The absence of an outer protective lipid layer reduces the evaporation time for the tear film covering the eye leading to interrelated issues of inadequate production of tears and meibum. 
     Some treatments for Meibomian gland dysfunction include using warm compresses, eyelid cleansing compounds, and massaging the eyelids gently to try to reduce eyelid inflammation. Other known eye treatments include heating the outside of the eyelids using heating pads. Some treatments for inadequate tear production include application of various types of artificial tears. Known treatments either lack effectiveness or are too costly. 
     Thus, there remains a need for less costly and more convenient ways of treating dry eye disease generally, and Meibomian gland dysfunction and/or inadequate tear production in particular. 
     SUMMARY 
     The present disclosure advantageously describes a system for treating dry eye. According to some aspects, the system includes an underlid device having an anterior surface and a posterior surface, wherein the anterior surface is configured to contact a portion of an eyelid, and wherein the posterior surface is configured to contact a portion of an eyeball. The underlid device further includes a Peltier heat pump. The Peltier heat pump includes a first surface configured to heat the eyelid when the underlid device is positioned between the eyelid and the eyeball, and a second surface configured to cool a portion of a surface of the eyeball when the underlid device is positioned between the eyelid and the eyeball. The underlid device further includes an energy storage element coupled to the Peltier heat pump and configured to supply power to the Peltier heat pump. Some embodiments further include a buck converter configured to couple the energy storage element to the Peltier heat pump. 
     In some aspects, the present disclosure describes a device for treating dry eye and configured to be positioned between an eyelid and sclera. The device includes a first surface that is convex for contacting the eyelid and a second surface that is concave for contacting the sclera. The device further includes an energy storage device and a Peltier device. The Peltier device includes a third surface configured to heat a portion of the eyelid and a fourth surface configured to cool a portion of the sclera when power is delivered to the Peltier device. The device further includes a circuit configured to couple the energy storage device to the Peltier device to supply power to the Peltier device, wherein heat is transferred within the Peltier device when power is supplied to the Peltier device resulting in heating of the third surface and cooling of the fourth surface, thereby heating the portion of the eyelid and cooling the portion of the sclera, respectively. In some embodiments, the circuit includes a buck converter. 
     In some aspects, the present disclosure describes a method of ophthalmic treatment using an underlid device when the underlid device is positioned beneath the surface of an eyelid. The underlid device includes an energy storage element, a buck converter and a Peltier device connected in series. The Peltier device includes a first surface and a second surface, wherein the first surface is configured to heat a portion of the conjunctiva of the eyelid and the second surface is configured to cool a portion of the sclera. The Peltier device is configured to transfer heat such that the first surface increases in temperature and the second surface decreases in temperature when power is supplied using the energy storage element and the buck converter. The method includes generating a signal, by a sensor, determining that a condition is satisfied based on the signal, and based on the condition being satisfied, supply power to the Peltier device using the energy storage element and the buck converter to heat the first surface and cool the second surface, thereby heating the portion of the conjunctiva and cooling the portion of the sclera. 
     Additional aspects, features, and advantages of the present disclosure will become apparent from the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Illustrative embodiments of the present disclosure will be described with reference to the accompanying drawings, of which: 
         FIGS. 1A and 1B  present different views of a system for treating dry eye, according to some aspects of the present disclosure. 
         FIG. 2  is a block diagram of an embodiment of an underlid device, according to some aspects of the present disclosure. 
         FIG. 3  is a circuit diagram of an embodiment of a buck converter in an underlid device, according to some aspects of the present disclosure. 
         FIGS. 4A and 4B  are perspective views of portions of different embodiments of underlid devices that include a Peltier device, according to some aspects of the present disclosure. 
         FIG. 5  is a block diagram of components in a frame, according to some aspects of the present disclosure. 
         FIG. 6  is a view of an eyelid side of an underlid device, according to some aspects of the present disclosure. 
         FIG. 7  presents a method of operating an underlid device, according to some aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It is nevertheless understood that no limitation to the scope of the disclosure is intended. Any alterations and further modifications to the described devices, systems, and methods, and any further application of the principles of the present disclosure are fully contemplated and included within the present disclosure as would normally occur to one skilled in the art to which the disclosure relates. For example, while therapeutic devices are illustrated in terms of devices placed underneath a lower eyelid for treatment of dry eye, the devices can also be placed underneath an upper eyelid for treatment of dry eye. In particular, it is fully contemplated that the features, components, and/or steps described with respect to one embodiment may be combined with the features, components, and/or steps described with respect to other embodiments of the present disclosure. For the sake of brevity, however, the numerous iterations of these combinations will not be described separately. 
     An exemplary system  100  for treating dry eye according to one embodiment is illustrated in  FIG. 1A . As shown, the system  100  includes a pair of devices  110 , each device  110  positioned between a lower eyelid and a patient&#39;s eyeball, a frame  120  worn by the patient, and a communication device  130 , such as a smartphone, cellular phone or tablet.  FIG. 1B  is a cross-sectional side view of device  110  positioned between an eyelid  140  and eyeball  150 , with the cross-section along the line indicated in  FIG. 1A .  FIG. 1B  illustrates the eyelid  140  and eyeball  150  spaced apart from the device  110 , but in use the device  110  will typically touch at least a portion of eyeball  150  and at least a portion of eyelid  140 . 
     As shown in  FIG. 1A , each device  110  is configured to cover only a portion of the surface of an eyeball residing underneath an eyelid when the eyelid is open and not cover any portion of the pupil. Thus, the form factor of each device is significantly different than a contact lens, which is typically designed to cover the entire pupil when worn. In other words, in some embodiments, each device  110  is configured to reside against only the sclera. Although each device  110  is illustrated as residing underneath a lower eyelid, each device  110  may instead reside underneath an upper eyelid for treatment of dry eye. 
     Each device  110  is located underneath an eyelid and adjacent to an inner surface of the eyelid, as illustrated in  FIG. 1B , and an outline of a top view of each device  110  as projected on an outer surface of a patient&#39;s skin is shown in  FIG. 1A . In some embodiments, each device  110  may be referred to as an underlid device  110 . Although two devices  110  are shown in  FIG. 1A , a patient may only wear one device  110  at a given time. In an embodiment, each device  110  includes a Peltier device (not shown), sometimes referred to as a Peltier heat pump, as discussed further herein. 
     The device  110  comprises a first surface (or anterior surface)  114  configured to heat the eyelid when the device is positioned underneath the eyelid. Correspondingly, the device  110  comprises a second surface (or posterior surface)  116  configured to cool a surface of an eyeball when the device  110  is positioned underneath the eyelid. In some embodiments, the second surface cools scleral nerves. Directing heat to the underside of an eyelid heats Meibomian glands in the eyelid. Heating Meibomian glands may loosen oils, such as meibum, clogging or partially clogging the glands, so that the glands are unclogged, thereby secreting sufficient oil onto the surface of the eye. Insufficient oil secretion from Meibomian glands is associated with dry eye syndrome. Cooling a surface of the eyeball (using the Peltier device) may stimulate tear production, also to treat dry eye issues, such as aqueous deficient dry eye disease. These and other aspects of underlid devices  110  are explained further herein. As shown in  FIG. 1B , in some embodiments, the first surface  114  is convex in order to better align with an adjacent surface of the eyelid  140 , and the second surface  116  is concave in order to better align with an adjacent surface of eyeball  150 . 
     The frame  120  may include portions that reside over a person&#39;s ear (not shown) to hold the frame  120  in place, and the frame  210  may or may not include glass eyepieces. The frame  120  may be any sort of known eyeglass frame form factor. The frame  120  may be referred to as an external frame because it is worn outside of a human body. 
     The frame  120  wirelessly communicates with the devices  110 , according to an embodiment. For example, the frame  120  is in communication with devices  110  to receive data from one or both devices  110 . For example, a device  110  may include one or more sensors to measure variables such as temperature, blink rate, or tear osmolarity, and information collected from measurements may be communicated from a device  110  to frame  120 . In an embodiment, the frame  120  also wirelessly charges each device  110  by transmitting power to each device  110 , using conventional wireless charging techniques, as discussed further herein. 
     In an embodiment, the communication device  130  communicates wirelessly with frame  120 . For example, the communication device  130  may receive data collected by frame  120 , or may transmit operating instructions to frame  120 . In an embodiment, the communication device  130  aggregates and/or processes received data and transmits such data or processed data to other devices via a network (not shown), such as the Internet. 
       FIG. 2  presents a block diagram of an embodiment of an underlid device  110 . In this embodiment, the device  110  includes one or more energy storage devices  210 , one or more circuit components  220 , such as antennas or coils, configured for wireless charging and communication, a processor  230 , a buck converter  240 , a Peltier device  260 , and one or more sensors  250 . 
     An energy storage device  210  stores energy for powering device  110  (power is understood in the art to be energy delivered per unit time). Examples of an energy storage device  210  include a capacitor, such as a supercapacitor, or a battery. The energy storage device  210  includes two or more supercapacitors, which are connected in series or in parallel, according to an embodiment. 
     An example circuit component  220  is an antenna, such as a loop antenna. The antenna generally can take any useful form for performing wireless charging via inductive wireless charging and/or for providing communications capability for the device  110 . The antenna may reside on a surface of the device  110  or may reside inside the device  110 . 
     Exemplary device  110  in  FIG. 2  includes one or more sensors  250  as shown. An example sensor  250  is a pair of electrodes. Such electrodes may be configured to sense the onset of a blink via electromyography (EMG) to provide blink detection. For example, the electrodes may measure electric potential or voltage generated by a conjunctiva or other cells in the eyelid to detect the onset of a blink. The electrodes may also, or alternatively, be configured to stimulate the eyelid muscles to cause a person to blink. Sensors  250  may also include a temperature sensor configured to generate a temperature signal based on a temperature of Meibomian glands. In one embodiment, when the underlid device  110  is placed or mounted underneath an eyelid, such a temperature sensor is positioned to contact a portion of the conjunctiva, adjacent to the Meibomian glands. Sensors  250  may also include an osmolarity sensor configured to generate a moisture signal indicative of an amount of moisture, such as an amount of tear solution, in contact with the sensor. For example, a pair of electrodes can be used to measure tear conductance or impedance, which is used as a measure of tear osmolarity, and the processor  230  may utilize a look-up table or formula to convert conductance measurements to osmolarity values. In an embodiment, the electrodes are formulated from platinum iridium. For example, if a small voltage (AC or DC) is applied across the electrodes, a small current (AC or DC) is generated that can be measured, with the resulting impedance computed as the complex voltage divided by the complex current according to Ohm&#39;s law. 
     As shown, the device  110  in  FIG. 2  also includes a processor  230 . The processor  230  may take the form of any known processor, such as an integrated circuit (IC), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a general-purpose processor. The processor  230  is configured to provide any combination of the following: heating control, power management (such as managing the energy storage element  210  or energy harvesting via wireless charging), EMG blink sensing, blink timing, or stimulating the blink reflex, according to an embodiment. For example, in some embodiments, processor  230  couples to sensors  250  (such as a pair of electrodes) to provide both blink sensing and blink stimulation, taking one or more measurements from electrodes to perform blink sensing and applying voltages or currents to electrodes to perform blink stimulation by stimulating the eyelid. 
     The device  110  in  FIG. 2  also includes a Peltier device  260 , sometimes referred to as a Peltier heat pump. A voltage applied across a Peltier device, such as Peltier device  260 , causes heat transfer within the device, such that one side of the Peltier device increases in temperature and an opposite side of the Peltier device decreases in temperature, resulting a temperature difference or gradient across the Peltier device. 
     The Peltier device  260  comprises a first surface (or anterior surface) configured to heat the eyelid when the device is positioned underneath the eyelid. Correspondingly, the Peltier device  260  comprises a second surface (or posterior surface) configured to cool a surface of an eyeball when the device is positioned underneath the eyelid. In some embodiments, the second surface cools scleral nerves. By powering the Peltier device  260 , such as using the energy storage device  210  to apply a voltage across Peltier device  260 , the Meibomian glands are heated, and the scleral nerves are cooled when the ophthalmic device  110  is mounted or positioned underneath an eyelid of the eye. By heating Meibomian glands, sufficient oils may be produced to relieve dry eye, and cooling scleral nerves can trigger reflex tear production also relieving dry eye. Cooling scleral nerves also can trigger a blink reflex, which coincides with Meibomian gland heating to provide additional assistance in oil flow from Meibomian glands. Thus, the Peltier device  260  is a convenient device for treating Meibomian gland dysfunction and/or aqueous deficient dry eye disease, leading to increased flow of meibum oil and/or increased tear production, according to at least one embodiment. 
     The device  110  in  FIG. 2  also includes buck converter  240 . A buck converter, such as buck converter  240 , is a type of DC-to-DC power converter. This disclosure recognizes that a buck converter  240  provides relatively high efficiency power delivery to the Peltier device  260 . For example, some embodiments achieve 50% efficiency, compared with roughly 1% efficiency when a buck converter is not used. This disclosure recognizes that a buck converter  240  delivers sufficient power for operating the device  110 , despite sometimes producing undesirable voltage ripple, and recognizes that the resulting device  110  operates sufficiently. Accordingly, this disclosure recognizes that a power supply that includes one or more supercapacitors connected in series with a buck converter supplies sufficient power to the Peltier device  260  and other components to operate the device  110 , according to at least one embodiment. More generally, some embodiments utilize a known circuit coupled between the Peltier device  260  and energy storage device  210  for delivering power from a DC power source to a Peltier device. In some embodiments, such a circuit includes a buck converter. 
     An example embodiment of a buck converter  240  is illustrated in  FIG. 3 . In this embodiment, the buck converter includes a switch  342  (such as one or more transistors), a diode  344 , an inductor  346 , and a capacitor  348  configured as shown in  FIG. 3 . The buck converter  240  operates in an “on-state” when switch  342  is closed and in an “off-state” when switch  342  is open. As shown in  FIG. 3 , the buck converter  240  is connected between the energy storage device  210  and Peltier device  260 . In some embodiments, the energy storage device  210  and Peltier device  260  together form all or part of a power supply. 
     A processor or controller, such as processor  230 , controls the operation of the switch  342 , according to one embodiment. In some embodiments, the switch is closed periodically for a duration of time and then opened at the end of the duration of time, and the process is repeated. Both the period and the duration of time may be adjustable to adjust the frequency of operation (computed as inverse of the period), periodicity and/or duty cycle. For example, the switch  342  may be closed for a half cycle and opened for a half cycle, wherein the cycle repeats at a frequency of several or tens or hundreds of kilohertz (kHz). 
     According to some experiments, 50 milliwatts (mW) of power may be used to power the underlid device  110 . Operating at 50 mW for is requires 50 millijoules (mJ) of energy. Energy stored in a capacitor can be represented as 0.5*C*V2, where C represents capacitance and V represents voltage. As an example, a 7.5 millifarad (mF) supercapacitor, as an example energy storage device  210 , operating at 2.6V with a 25Ω source impedance provides a small form factor. A DC-to-DC power converter, such as a buck converter, must be able to deliver 50 mW into a 0.3Ω load, according to some embodiments. 
     According to some embodiments, a buck converter  240  using a 30 microhenry (uH) inductor  346  that is 1 mm×0.5 mm×6 mm, switching at 100 kHz (using switch  342 ), is both desirable and realizable. Such a device may be about 50% efficient (limited by supercapacitor source resistance and other losses). This is much better than alternative embodiments that achieve only 1% efficiency when a buck converter is not used. 
     In some embodiments, wireless charging of a device  110 , for example using a wireless charger in frame  120 , can occur at a 20 microampere (μA) rate. A 20 μA rate of charging would take roughly 16 mins to recharge a 2.6V, 7.5 mF capacitor. It is possible to boost charging past 20 uA (e.g., up to 100 μA), which would increase the rate of charging at the expense of higher cost or complexity. Wireless charging of the device  110  may occur while power is being delivered to a Peltier device  260 , according to some embodiments. 
       FIGS. 4A and 4B  present perspective views of portions of different embodiments of underlid device  110  that include a Peltier device  260 . In operation, a voltage is applied across Peltier device  260  which results in heat transfer from one portion of the Peltier device  260  to another. Referring to  FIGS. 4A and 4B , when a voltage is applied across the Peltier device  260 , one surface  422  increases in temperature and another surface  424  decreases in temperature as heat transfer occurs within the device  260 . There is thus a temperature gradient produced across the Peltier device  260 , between a higher temperature surface  422  to a lower temperature surface  424 . 
     The Peltier device  260  in  FIG. 4A  is surrounded by a thermal insulator  420 , such as silicone, that helps restrict unwanted loss of heat from the Peltier device  260 , such as through heat transfer by radiation from the device  260  or conduction from the device  260  to surrounding materials. In use, the surface  422  is positioned proximate an eyelid and the surface  424  is positioned proximate an eyeball. When electric power is supplied to the Peltier device  260  to cause heat transfer, the surface  422  is used to heat Meibomian glands in the eyelid, thereby loosening oils that have solidified and blocked or partially blocked Meibomian glands, and the surface  424  is used to cool scleral nerves in the eyeball, which can have the effect of inducing tear production, thereby treating dry eye by replacing evaporated tear solution. 
     The Peltier device  260   FIG. 4B  is not necessarily surrounded by a thermal insulator but rather surfaces  422  and  424  are adjacent to, with at least a portion resting against, thermal conductors  426  and  428 , respectively. An example thermal conductor is a hydrogel, which is also comfortable for patients. In use, the surface  422  is positioned proximate an eyelid and the surface  424  is positioned proximate an eyeball. When voltage is applied to the Peltier device  260  to cause heat transfer, the surface  422  is used to heat Meibomian glands in the eyelid, as the thermal conductor  426  facilitates heat transfer from surface  422  to the eyelid, and the surface  424  is used to cool scleral nerves in the eyeball, as the thermal conductor  428  facilitates heat transfer from the eyeball to surface  424 . A thermal conductor is a material generally understood to provide relatively high thermal conductivity, such as thermal conductivity exceeding 100 W/m/K (Watts/meter/Kelvin) at around 293 K and atmospheric pressure. A thermal insulator is a material generally understood to provide relatively low thermal conductivity, such as thermal conductivity below 1 W/m/K at the conditions described above. 
       FIG. 5  is a block diagram of components in a frame  120 , according to an embodiment. In this embodiment, frame  120  includes energy source  510 , a power delivery subsystem  550 , a processor  530 , communication transceivers  520  and  540 , and a memory  560 . The energy source  510  provides energy for the other components in the frame  120 , and a battery or one or more capacitors are examples of energy source  510 . 
     The energy source  510  may also provide energy to power the underlid device  110 . The power delivery subsystem  550  allows power to be delivered from frame  120  to at least one underlid device  110 , such as via wireless charging. For example, the power delivery subsystem  550  includes one or more coils (sometimes referred to herein as wireless charging coils) for electromagnetic coupling with one or more coils in an underlid device  110  to perform inductive wireless charging, according to an embodiment. 
     The communication transceiver  520  performs communication between the frame  120  and underlid device  110 . For example, the communication transceiver  520  receives data collected in an underlid device  110 . The data collected in the underlid device  110  may include temperature, osmolarity, and/or blink rate measurements. The communication transceiver  520  may utilize near-field communications (NFC), radio-frequency identification (RFID), or Bluetooth Low Energy (BLE) as examples. 
     The communication transceiver  540  performs communication between the frame  120  and a communication device  130 , such as a cell phone or smart phone. For example, if the frame  120  receives data collected in an underlid device  110 , the frame  120  can use communication transceiver  540  to send the collected data to the communication device  130 , so that the data may ultimately be shared with a physician or other health care provider. As another example, the frame  120  may receive instructions for operation of the underlid device  110  from a physician or other health care provider. 
     The processor  530  in  FIG. 5  is configured to control the operation of communication transceivers  520  and  540  and power delivery subsystem  550 . The memory  560  is a semiconductor memory used to store data and/or instructions for other components. The memory  560  is any suitable semiconductor memory, such as a random-access memory (RAM) (such as a synchronous dynamic RAM or SDRAM), a read-only memory (ROM) (such as a programmable ROM or PROM), a flash memory or any combination thereof. The memory  560  may be used to store the instructions for operating processor  530 , and/or transceivers  520  and  540 . The processor  530  is any suitable processor, such as an integrated circuit (IC), a field-programmable gate array (FPGA), digital signal processor (DSP), or general-purpose processor. 
     Generally, any creation, storage, processing, and/or exchange of user data associated with the method, apparatus, and/or system disclosed herein is configured to comply with a variety of privacy settings and security protocols and prevailing data regulations, consistent with treating confidentiality and integrity of user data as an important matter. For example, the apparatus and/or the system, such as device  110 , frame  120 , and/or system  100 , may include a module that implements information security controls to comply with a number of standards and/or other agreements. In some embodiments, the module receives a privacy setting selection from the user and implements controls to comply with the selected privacy setting. In other embodiments, the module identifies data that is considered sensitive, encrypts data according to any appropriate and well-known method in the art, replaces sensitive data with codes to pseudonymize the data, and otherwise ensures compliance with selected privacy settings and data security requirements and regulations. 
       FIG. 6  is a planar view of an eyelid side of an underlid device  110 , according to one embodiment. The underlid device  110  in  FIG. 6  includes a Peltier device  260 , as described herein, and electrodes  620 . The electrodes  620  may be used for blink detection. For example, the electrodes  620  may be configured to sense the onset of a blink via electromyography (EMG) to provide blink detection. The electrodes  620  are examples of sensors  250  presented in the embodiment in  FIG. 2 . In an embodiment, a portion of the surface of each of the electrodes  620  extends to the outer surface of the device  110 . Likewise, in an embodiment, a portion of the surface of the Peltier device  260  extends to the outer surface of the device  110 . Alternatively, the device  110  is covered by an overmold, such as using a silicone elastomer, suitable for contacting surfaces of the eye and eyelids, and the electrodes  620  and/or Peltier device  260  are located entirely beneath the surface of the overmold. 
       FIG. 7  presents a method  700  of operating an underlid device, such as the embodiments of underlid devices  110  described previously. The method  700  commences in step  710 . In step  710 , an underlid device, such as the embodiments of underlid devices  110  described previously, is positioned underneath an eyelid. For example, an underlid device is placed between an eyelid and eyeball as shown in  FIG. 1B . Once positioned, in step  720  a determination is made whether a condition is satisfied. In one embodiment, sensors, such as sensors  250  described previously, are used to provide information to a processor, such as processor  230 , in the underlid device, for use in determining whether the condition is satisfied. 
     Based on sensor readings, the processor determines whether a condition is satisfied. According to one embodiment, the sensors may include a pair of electrodes, and the electrodes are used to measure tear film conductance or impedance, which can be used to provide a measure of tear osmolarity as discussed herein. In one embodiment, if the tear osmolarity exceeds a threshold, thereby signaling a dry eye condition, the condition in step  720  is satisfied and a electrical power is supplied to a Peltier device to apply a heated surface of the underlid device to Meibomian glands and a cooled surface to the surface of the eye, thereby providing relief to or treating the dry eye condition. In one embodiment, a temperature sensor may be included and used to provide a measurement of temperature of an area on or near a surface of the patient underneath the eyelid, and, if the temperature exceeds a threshold, the Peltier devices will not be activated. Thus, a temperature sensor can be used to protect the eyelid from excessive heating. 
     The same or a different pair of electrodes can be used as a sensor for blink detection, as discussed herein. By detecting blinks and keeping track of the time between blinks, the underlid device can compute a blink rate. The blink rate may be used as a condition in step  720 . For example, if the blink rate is too low, the method  700  moves to step  730  in which power is supplied to a Peltier device in the underlid device to stimulate blinking. 
     In step  730 , power is supplied to a Peltier device to activate the Peltier device. The Peltier device may be activated according to a period and duty cycle. For example, the period may be one minute, and the duty cycle may be one percent, such that the Peltier device is activated one percent of each minute for some duration of time. The period and duty cycle may be programmable parameters stored in an underlid device. After the period of time in step  730 , the state of the device returns to step  720  to check whether a condition is satisfied and the process repeats. Power may be supplied to the Peltier device using a buck converter, e.g., by periodically opening and closing the switch in a Peltier device at a given frequency, such as 100 kHz, resulting in continuous power delivery. 
     During the method  700 , a frame is worn by the patient, such as the frame  120  described with respect to  FIGS. 1A and 5 , according to an embodiment. In an embodiment, the frame includes a larger energy source that is used to supply energy to the underlid devices, e.g., through wireless charging as discussed herein. In another embodiment, a periocular ring worn on the eye can be used to supply energy to the underlid device. In such an embodiment, the periocular ring includes a coil and energy storage component for wirelessly charging the underlid device. 
     Generally, any creation, storage, processing, and/or exchange of user data associated with the method, apparatus, and/or system disclosed herein is configured to comply with a variety of privacy settings and security protocols and prevailing data regulations, consistent with treating confidentiality and integrity of user data as an important matter. For example, the apparatus and/or the system may include a module that implements information security controls to comply with a number of standards and/or other agreements. In some embodiments, the module receives a privacy setting selection from the user and implements controls to comply with the selected privacy setting. In other embodiments, the module identifies data that is considered sensitive, encrypts data according to any appropriate and well-known method in the art, replaces sensitive data with codes to pseudonymize the data, and otherwise ensures compliance with selected privacy settings and data security requirements and regulations. 
     Persons skilled in the art will recognize that the devices, systems, and methods described above can be modified in various ways. Accordingly, persons of ordinary skill in the art will appreciate that the embodiments encompassed by the present disclosure are not limited to the particular exemplary embodiments described above. In that regard, although illustrative embodiments have been shown and described, a wide range of modification, change, and substitution is contemplated in the foregoing disclosure. It is understood that such variations may be made to the foregoing without departing from the scope of the present disclosure. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the present disclosure.