Patent Publication Number: US-2022226156-A1

Title: Intraocular micro-display system with intelligent wireless power delivery

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/846,428, filed May 10, 2019, which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     This disclosure relates generally to ophthalmic devices, and in particular but not exclusively, relates to intraocular micro-displays. 
     BACKGROUND INFORMATION 
     Disease or injury to the cornea can lead to opacification or significant optical damage to the cornea, such that the individual is effectively rendered blind. The blindness may occur despite the patient having a fully functioning retina. For these patients with an intact retina but otherwise blind due to vascularization or damage to the cornea, implantation of an intraocular micro-display in the excised lens of the eye (e.g., capsular sack region) can restore image reproduction onto their fully functioning retina, thereby returning vision to the patient. 
     A proposed solution for an electronic intraocular micro-display involves the use of a transcutaneous tether that couples a wireless transmitter positioned behind the ear to the intraocular micro-display. This tether provides power and data communication to the intraocular micro-display. The transcutaneous nature and complex surgery required for this proposed solution, likely makes this solution prone to physiological compatibility issues and inflammation. Since the tether protrudes outside of the eye and back into subcutaneous flesh on the side of the face, the tether also presents an infection risk. 
     To avoid the use of a transcutaneous tether, the intraocular micro-display and related circuitry must have a sufficiently compact form factor to fit entirely within the eye in the region of the capsular sack. As such, power delivery, power storage, and power management of such a small display system presents a significant challenge. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Non-limiting and non-exhaustive embodiments of the invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. Not all instances of an element are necessarily labeled so as not to clutter the drawings where appropriate. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles being described. 
         FIGS. 1A and 1B  are plan and side view illustrations of an intraocular micro-display (IOMD) system including an IOMD implant and an auxiliary head unit, in accordance with an embodiment of the disclosure. 
         FIG. 1C  is a cross-sectional illustration of the IOMD system with the the IOMD implant implanted within an eye for projecting images onto a retina, in accordance with an embodiment of the disclosure. 
         FIG. 2  is a functional block diagram of an auxiliary head unit, in accordance with an embodiment of the disclosure. 
         FIG. 3  is a functional block diagram of an IOMD implant, in accordance with an embodiment of the disclosure. 
         FIG. 4  is a block diagram illustrating a communication protocol between the IOMD implant and the auxiliary head unit for delivering power and image data to the IOMD implant from the auxiliary head unit, in accordance with an embodiment of the disclosure. 
         FIG. 5  is a flow chart illustrating a process for adjusting image data transmitted to the IOMD implant based upon an ACK signal to throttle power consumption of the IOMD implant, in accordance with an embodiment of the disclosure. 
         FIG. 6  is a diagram illustrating techniques of fading images transmitted to the IOMD implant between multi-color and monochrome, in accordance with an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of a system, apparatus, and method of operation for delivering power and image data to an intraocular micro-display (IOMD) implant from an auxiliary head unit are described herein. In the following description numerous specific details are set forth to provide a thorough understanding of the embodiments. One skilled in the relevant art will recognize, however, that the techniques described herein can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring certain aspects. 
     Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. 
     Embodiments of the IOMD system disclosed herein are suitable for patients with intact retinas, yet are blind due to vascularization, occlusion, opacity, or otherwise damage of the cornea. The disclosed IOMD system seeks to restore sight to these patients by implanting an electronic micro-display (referred to as an intraocular micro-display or IOMD) into the eye, such as in the capsular sack region of the eye previously occupied by an excised lens. The IOMD is included within an IOMD implant to project reproduced images onto the patient&#39;s fully functioning retina. 
     Embodiments disclosed herein leverage advances in wireless power transfer technologies and miniaturized electronics to achieve wireless power transfer and wireless image data transfer from an auxiliary head unit that is worn on, or otherwise mounted to, the patients head. The power and image data signals are wirelessly communicated to an IOMD implant that is surgically positioned in the same area of the eye where an intraocular lens (IOL) would be placed. As such, the form factor of the IOMD implant should be compact, leaving little room for onboard energy storage, data processing, and data reception circuitry. Accordingly, some embodiments disclosed herein describe a batteryless implant that instead relies upon inductive charging of a compact capacitor (e.g., supercapacitor). Capacitors have much longer life spans than rechargeable batteries, thus reducing the need for surgically replacing a battery. In some embodiments, the inductive charging circuitry is used to extract a clock signal from the auxiliary head unit, which is then leveraged to support higher frequency/bandwidth synchronous data communications (e.g., for real-time image transfer) between the IOMD implant and the auxiliary head unit. With synchronous data communications and inductive charging, fewer, simpler, and more compact electronic components with longer serviceable lifespans are used within the IOMD implant to support high bandwidth wireless data communications between the auxiliary head unit and the IOMD implant. 
     An IOMD that runs at a traditional full color, 20 fps may consume significant power, and thus generate significant heat, over sustained periods of operation. Accordingly, some embodiments describe the use of an acknowledgement (ACK) signaling protocol from the IOMD implant back to the auxiliary head unit to throttle power consumption based upon implant temperature, power reception strength, and overall power budgeting needs of the system. In various embodiments, power consumption is throttled by adjusting image frame rates and/or by fading multi-color images to monochromatic images using a variety of techniques as described below. 
       FIGS. 1A, 1B, and 1C  illustrate an IOMD system  100  that includes an IOMD implant  105  and an auxiliary head unit  110 , in accordance with an embodiment of the disclosure.  FIGS. 1A and 1B  are plan and side view illustrations, respectively, while  FIG. 1C  is a cross-sectional illustration of IOMD system  100 . The illustrated embodiment of auxiliary head unit  110  includes a frame  115 , a camera module  120 , an antenna mount  125 , a charging antenna  130 , a data antenna  135 , embedded electronic circuitry  140 , and a user interface  145 . The illustrated embodiment of antenna mount  125  includes a flexible eye-safe enclosure  150  mounted to frame  115  via an articulating arm  155 . The illustrated embodiment of IOMD implant  105  includes an enclosure  160  in which electronics are disposed along with focusing optics  165 . 
     During operation auxiliary head unit  110  inductively powers IOMD implant  105  via power signal  131  output from charging antenna  130 . Auxiliary head unit  110  further captures forward facing images with camera module  120  and wirelessly transmits those images to IOMD implant  105  via data signals  136 . In one embodiment, this image capture and transmit is executed in real-time. IOMD implant  105  harvests energy from power signal  131 , uses that energy to power receiver and controller circuitry for decoding data signals  136  and display circuitry for projecting the image onto retina  170  of eye  175 . Again, in one embodiment, the reception, decoding, and display of the image data are executed in real-time and provide the user with virtual, real-time, forward facing vision. 
     Auxiliary head unit  110  includes frame  115  for mounting auxiliary head unit  110  to the user&#39;s head. Although  FIGS. 1A-C  illustrate frame  115  in the shape of eyeglasses, it should be appreciated that frame  115  may assume a variety of different shapes and configurations for mounting to the user&#39;s head including an eyepatch, googles, a visor, headgear, or otherwise. Camera module  120  is disposed in or on frame  120  and oriented to acquire images in the direction of the user&#39;s forward vision. Antenna mount  125  includes an articulating arm  155  to get at least power antenna  130  close to the user&#39;s eye  175  for effective wireless charging of IOMD implant  105 . As such, antenna mount  125  includes a flexible eye-safe enclosure  150  in which charging antenna  130  is disposed. In the illustrated embodiment, data antenna  135  is also disposed within flexible eye-safe enclosure  150  for close proximity to IOMD implant  105 . In other embodiments, data antenna  135  may be disposed elsewhere within frame  115 . In yet another embodiment, power antenna  130  and data antenna  135  may be the same physical antenna operated at different frequencies. Eye-safe enclosure  150  may be fabricated of a variety of soft, flexible, dielectric materials, such as molded silicon, etc. Although  FIGS. 1A-C  illustrate auxiliary head unit  115  as a single contiguous frame, in other embodiments, auxiliary head unit  115  may be segmented into two or more body-wearable modular components that may be interconnected and mounted or worn in various locations about the body or clothing. Furthermore, although  FIGS. 1A-C  illustrate a monocular IOMD system, the illustrated components may be replicated to implement a binocular IOMD system. 
     As illustrated, IOMD implant  105  is entirely disposed within eye  175  and does not include electronic cables or tethers extending out of eye  175  to auxiliary head unit  110 . Similarly, auxiliary head unit  110  is an independent, discrete unit that is worn on the user&#39;s head. Auxiliary head unit  110  includes embedded electronics for powering and orchestrating the operation of IOMD system  100  including itself and IOMD implant  105 . 
       FIG. 2  is a functional block diagram of an auxiliary head unit  200 , in accordance with an embodiment of the disclosure. Auxiliary head unit  200  is one possible implementation of auxiliary head unit  110 . The illustrated embodiment of auxiliary head unit  200  includes a frame  201 , a power source  205 , a wireless power transmitter  210 , a camera module  215 , an auxiliary controller  220 , a data transceiver  225 , a clock  230 , a user interface  235 , a power antenna  240 , and a data antenna  245 . 
     Power source  205  is provided within frame  201  to power the internal electronics of auxiliary head unit  200  and IOMD implant  105  via inductive power transfer. In one embodiment, power source  205  is a rechargeable battery (e.g., lithium ion battery). IOMD implant  105  is inductively charged via wireless power transmitter  210  and power antenna  240 . In one embodiment, wireless power transmitter  210  emits power signal  131  as a continuous wave signal having a sufficiently low frequency f 1  (e.g., 13.5 MHz, 27 MHz, etc.) for efficient eye-safe power coupling. The frequency of wireless power transmitter  210  may be based upon clock  230 . In one embodiment, clock  230  is a high fidelity, low power resonator, such as a quartz crystal oscillator. 
     Power source  205  also powers camera module  215 , auxiliary controller  220 , and data transceiver  225 . Camera module  215  may include a charged coupled device (CCD) sensor, a complementary metal-oxide-semiconductor (CMOS) sensor, or otherwise that acquires the images relayed to IOMD implant  105 . Data transceiver  225  transmits the image data representing the acquired images as data signals  136 . Data signals  136  are encoded on a carrier signal having a frequency f 2  (e.g., 2.4 GHz). Data transceiver  225  may use any number of encoding techniques including one or more of frequency modulation, phase modulation, amplitude modulation, and/or time multiplexing. Frequency f 2  is higher than frequency f 1 , since it can be transmitted at lower power for safety and provides a higher bandwidth for transmission of still or video images. In one embodiment, frequency f 2  is generated based upon clock  230  as well. For example, frequency f 2  may be a multiplied or upscaled version of frequency f 1 , or frequency f 1  may be a divided or downscaled version of frequency f 2 . In either case, clock signals based upon f 1  and f 2  may be phase aligned to support synchronous data communications where f 2  is regenerated at IOMD implant  105  based upon f 1 . 
     Auxiliary controller  220  orchestrates the operation of the other functional components. For example, auxiliary controller  220  may receive and decode an acknowledgment (ACK) signal  250  from IOMD implant  105 , and in response, adjust the image data sent to IOMD implant  105  to throttle power consumption of IOMD implant  105 . ACK signal  250  may be received as a backscatter modulation of power signal  131  on power antenna  240 , or received as an actively transmitted signal over data antenna  245 . In either case, ACK signal  250  may operate as an acknowledgement that a given image frame has been received and displayed by the IOMD implant  105 . Additionally. ACK signal  131  may also include an indication of reception strength of power signal  131  by IOMD implant  105  and/or an indication of operational temperature of IOMD implant  105 . Thus, IOMD implant  105  may use a low bandwidth return channel to transmit acknowledgments along with power readings and temperature readings. The acknowledgments, power readings, and temperature readings may then be used by auxiliary controller  220  to throttle power consumption of IOMD implant  105  by adjusting the frame rate and/or color characteristics of the image data transmitted to IOMD implant  105 . 
     By regulating the power consumption of IOMD implant  105 , auxiliary controller  220  is also regulating the power consumption of auxiliary head unit  200 , which is powering IOMD implant  105 . Accordingly, auxiliary controller  220  may decide to throttle the power consumption of IOMD implant  105  because IOMD implant  105  is approaching an upper limit safe operating temperature of eye  175  (e.g., 39 to 40 degrees Celsius upper limit), or because IOMD implant  105  is not harvesting sufficient power from power signal  131  to operate at full capacity (e.g., flexible eye-safe enclosure  150  has not been properly aligned by the end user). Additionally, auxiliary controller  220  may throttle power consumption of IOMD implant  105  because power source  205  is running low on power, or in response to a user request to enter a power conserve mode of operation. Accordingly, the image data may be adjusted due to power scarcity in one or both of IOMD implant  105  or auxiliary head unit  200 . 
     Auxiliary controller  220  may be implemented with hardware logic (e.g., application specific integrated circuit, field programmable gate array, etc.), implemented with software/firmware instructions stored in memory and executed by a microprocessor, or a combination of both. User interface  235  may include a variety of physical interfaces to enable the user to interact with IOMD system  100 . For example, user interface  235  may include a touch pad to receive gesture commands (e.g., swipe forward, swipe back, tap, double tap, etc.), one or more buttons, dials, switches, knobs, or otherwise. In one embodiment, auxiliary controller  220  may generate visual feedback overlays on the acquired images that are transmitted to IOMD implant  105 . These visual feedback overlays may include visual acknowledgments when the user interacts with user interface  235 , power readings of power source  205 , operational mode selections, temperature readings, a power coupling reading to aid the user in alignment of flexible eye-safe enclosure  150 , or otherwise. 
       FIG. 3  is a functional block diagram of an IOMD implant  300 , in accordance with an embodiment of the disclosure. IOMD implant  300  represents one possible implementation of IOMD implant  105 . The illustrated embodiment of IOMD implant  300  includes an enclosure  301 , a power antenna  305 , power harvesting circuitry  310 , an energy storage unit  315 , clock recovery circuitry  320 , a phase lock loop (PLL)  325 , an IOMD controller  330 , one or more sensors  335 , a transmit module  340 , a data antenna  345 , receiver circuitry  350 , a display controller  355 , a micro-display  360 , and optics  165 . The illustrated embodiment of power harvesting circuitry  310  includes a power rectifier  365  and a power converter  370 . The illustrated embodiment of receiver circuitry  350  includes a low noise amplifier (LNA)  375  and a demodulator  380 . 
     In the illustrated embodiment, the electronic components of IOMD implant  300  are housed within a biocompatible enclosure  301  that is sized and shaped for implantation into eye  175 . In one embodiment, enclosure  301  is sized for implantation into the region of the capsular sack of eye  175 . In one embodiment, enclosure  301  is a hermetically sealed enclosure fabricated of metal, polymers, or otherwise. 
     During operation, power signal  131  output from auxiliary head unit  110  is incident upon power antenna  305 . In various embodiments, power antenna  305  is disposed in or on enclosure  301 . In yet other embodiments, power antenna  305  may be externally attached or tethered to enclosure  301 , and implanted into another region of eye  175 , such as under the sclera. In one embodiment, power antenna  305  is a loop antenna suitable for harvesting inductive power operating at frequency f 1 . Power harvesting circuitry  310  is coupled to power antenna  305  to harvest the wireless power incident thereon. Power harvesting circuitry  310  includes power rectifier  365  and power converter  370 . In one embodiment, power rectifier  365  is implemented with one or more diodes for rectification while power converter  370  is implemented as a direct current (DC) to DC buck converter. Other power harvesting circuitry components may be used. Power harvesting circuitry  310  is used to charge energy storage unit  315 . In one embodiment, energy storage unit  315  is implemented with a capacitor, such as a supercapacitor. In yet other embodiments, a rechargeable battery may be implemented, though such implementations may have a shorter life span, and thus requiring periodic surgical replacement. Alternatively, energy storage unit  315  may be implanted into another region of eye  175  (e.g., under the sclera) and tethered to enclosure  301 . Placing a battery within the sclera may provide for less invasive replacement procedures. However, the components are all implanted into eye  175 , and thus less susceptible to infection compared to a transcutaneous tether extending external to the eye. 
     Clock recovery circuitry  320  is also coupled to power antenna  305  to extract and recover a synchronous clock signal from power signal  131  from auxiliary head unit  200 . Accordingly, clock recovery circuitry  320  operates to recover the lower frequency f 1  from the carrier wave of power signal  131 . Frequency f 1  (or a partial/whole multiple thereof) is then provided to the other circuit components of IOMD implant  300  for synchronous timing. In particular, PLL  325  may be used to lock onto the phase of the synchronous clock output from clock recovery  320  and an upconverted frequency f 2  provided to receiver circuitry  350  to synchronously demodulate data signal  136  received from auxiliary head unit  200  over data antenna  345 . Receiver circuitry  350  includes LNA  375  to amplifier data signal  136  and demodulator  380  to down convert and decode the higher frequency f 2  data signal  136 . Demodulator  380  may be implemented using a variety of decoding circuits, such as, an energy detect circuit, an IQ receiver, or otherwise. Data signals  136  may be modulated using one or more of frequency modulation, phase modulation, amplitude modulation, quadrature modulation, etc. 
     The decoded data signals  136  are then provided to display controller  355  as the image data to be displayed by micro-display  360 . In one embodiment, micro-display  360  is implemented as a multi-color light emitting diode (LED) display array. In other embodiments, micro-display  360  is a backlit liquid crystal display (LCD) or otherwise. Micro-display  360  outputs the image based upon the received image data, which is projected through focusing optics  165  onto retina  170 . 
     IOMD implant  300  also includes IOMD controller  330 , which serves to orchestrate the operation of the other functional components of IOMD implant  300 . As with auxiliary controller  220 , IOMD controller  330  may be implemented in hardware logic, implemented in software/firmware logic stored to a machine readable medium and executed by a microcontroller, or implemented in a combination of both. 
     In the illustrated embodiment, IOMD controller  330  is coupled to receive sensor readings from one or more sensors  335 . Sensor(s)  335  may include a temperature sensor to monitor the operational temperature of IOMD implant  300 . In this regard, the temperature sensor is a proxy reading for power consumption or power dissipation within IOMD implant  300 . The temperature sensor also serves as a safety measure to ensure the eye tissue surrounding IOMD implant  300  is not damaged due to elevated operational temperatures. 
     In one embodiment, sensors  335  also include a voltage sensor coupled to energy storage unit  315  to measure and monitor the voltage across the electrodes of energy storage unit  315 , and thus measure the stored energy. The measured voltage across energy storage unit  315  may also serve as a proxy for, or an indication of, the reception strength of power signal  131 . Alternatively, sensors  335  may be coupled to power harvesting circuitry  310  and/or power antenna  305  to directly measure received voltage. 
     IOMD controller  330  further includes logic for generating the ACK signal, which is transmitted back to the auxiliary head unit  200  via transmit module  340  as a feedback data path. Auxiliary head unit  200  uses the ACK signal to manage overall system power consumption by adjusting frame rates, color fading, and transmit power. The ACK signal may operate as an acknowledgment of each received image frame, an indication that the data frame was correctly received and displayed, an indication of the operating temperature of IOMD implant  300 , and an indication of reception strength (or a proxy thereof, such as voltage level on energy storage unit  315 ). 
       FIG. 3  illustrates two options for implementing the feedback data path. Option (1) illustrates transmit module  340  coupled to power antenna  305  to provide the feedback data path over the lower frequency f 1  wireless power charging path. With option (1), transmit module  340  operates as an RFID tag to modulate the impedance of power antenna  305  and generate ACK signal  250  as a backscatter modulation of power signal  131 . Option (2) illustrates transmit module  340  coupled to data antenna  345  to provide the feedback data path over the high frequency f 2  wireless data signal path. With option (2), transmit module  340  is an active transmitter for generating ACK signal  250 . Of course, options (1) and (2) need not be mutually exclusive, but rather, in some embodiments, both options may be implemented and used selectively based upon available power budget and bandwidth needs for the feedback data path. 
     In one embodiment, power antenna  305  is shaped as a loop antenna to harvest radio frequency or microwave frequency wireless power. However, it should be appreciated that power antenna  305  may assume a variety of sizes and shapes to harvest power from various frequencies of electromagnetic (EM) radiation. Similarly, data antenna  345  may assume a variety of different sizes and shapes to effectively receive (and optionally transmit) data signals  136  and/or ACK signal  250  at the higher frequency f 2  (e.g., 2.4 GHz or otherwise). For example, data antenna  345  may be a dipole antenna, a patch antenna, or otherwise. In one embodiment, data antenna  345  is an optical antenna (e.g., photo receiver or photo transceiver) and data signals  136  are optical wavelength EM radiation. In yet another embodiment, power antenna  305  and data antenna  345  may be implemented as a single physical antenna that is shared between power harvesting circuitry  310 , receiver circuitry  350 , and transmit module  340 . The sharing may be time sharing or frequency sharing where power harvesting circuitry  310  and transmit module  340  operate at frequency f 1  while receiver circuitry  350  operates on frequency f 2 . In this shared embodiment, power antenna  305  and data antenna  345  are graphical representations of the different functional uses for a single physical antenna. 
       FIG. 4  is a block diagram illustrating a communication protocol between IOMD implant  300  and auxiliary head unit  200  for delivering power and image data to IOMD implant  300  from auxiliary head unit  200 , in accordance with an embodiment of the disclosure. During operation, IOMD implant  330  receives data signal  136 . Receiver circuitry  350  decodes the data signal  136  to extract the image data, which is passed to micro-display  360  for projection of an image frame onto the retina  170 . In response, IOMD controller  330  commences building an ACK packet to acknowledge accurate reception and display of the image frame. Additionally, IOMD controller  330  monitors sensors  335  to determine the operating temperature of IOMD implant  300  and voltage level of energy storage unit  315 . In one embodiment, the voltage level of energy storage unit  315  is deemed to be a proxy for, or indication of, the reception or coupling strength of power signal  131  at power antenna  305 . IOMD controller  330  then generates the ACK packet for transmission as ACK signal  250 . In one embodiment, the ACK packet includes the acknowledgment, an indication of the current operating temperature, and an indication of the reception strength of power signal  131 . ACK signal  250  is then transmitted to auxiliary head unit  220 . 
     In response to receiving ACK signal  250 , auxiliary head unit  220  decodes the ACK packet to determine whether the previous image frame was received, the operating temperature of IOMD implant  300 , and the received power available to IOMD implant  300 . With this information, auxiliary controller  220  is able to make informed decisions for adjusting the frame rate and color fading of the image data encoded and transmitted to IOMD implant  300 . By adjusting the frame rate and color fading, auxiliary controller  220  effectively throttles the power consumption of IOMD implant  300 . In addition to considering the operating temperature and power reception of IOMD implant  300 , auxiliary controller  220  may also consider user requests (e.g., requests received via user interface  235 ) and the power level of power source  205  within auxiliary head unit  200 . For example, the user may request a power save mode, a high frame rate mode, etc. Accordingly, auxiliary controller  220  operates as the master of IOMD implant  300  taking into account user requests and its own power level, as well as, feedback from IOMD implant  300 , when throttling the power consumption of IOMD implant  300 . 
       FIG. 5  is a flow chart illustrating a process  500  executed by auxillary controller  220  for adjusting image data transmitted to IOMD implant  300  to throttle power consumption of IOMD implant  300 , in accordance with an embodiment of the disclosure. The decisions made by auxiliary controller  220  are based upon one or more of user requests, power levels (both IOMD implant received power and auxiliary head unit battery levels), and operating temperature of IOMD implant  300 . 
     In a decision block  505 , auxiliary controller  220  inspects ACK signal  250  to determine the reported operating temperature of IOMD implant  300 . If the operating temperature of IOMD implant  300  is greater than a temperature threshold T 1  (e.g., T 1 =39 degrees Celsius), then auxiliary controller  220  ceases transmission of image data to IOMD implant  300  (process block  510 ). For example, the upper threshold T 1  may be selected to be no more than 2 degrees Celsius above the expected body temperature of a human eye so as not to impart deleterious thermal heating or stress on the surrounding eye tissue. Additionally. IOMD implant  300  may include a safety mechanism that automatically disables IOMD implant  300  should its temperature rise above temperature threshold T 1  (process block  510 ). However, if the operating temperature of IOMD implant  300  is reported as residing between temperature thresholds T 1  and T 2  (e.g., T 1 =39 degrees Celsius and T 2 =37 degrees Celsius), then auxiliary controller  220  reduces the frame rate of images transmitted to IOMD implant  300  to reduce the processing power and heat dissipation needed to decode the images (process block  515 ). For example, the frame rate may be reduced to transmitting still images on a periodic basis (e.g. one image every 2 secs, 5 secs, 10 secs, or otherwise). This mode of operation may be referred to as “photograph mode.” The images transmitted in “photograph mode” may be color images, monochromatic images, or even fading combinations of monochromatic and multi-color images, as discussed below in connection with  FIG. 6 . The use of monochromatic images (or partial monochromatic images) consumes less power since fewer LEDs in a micro-LED display are activated. 
     Returning to decision block  505 , if the operating temperature of IOMD implant  300  is reported as being below temperature threshold T 2 , then process  500  continues to a decision block  520 . In decision block  520 , auxiliary controller  220  throttles the power consumption of IOMD implant  300  based upon the available power. Power consumption is throttled by adjusting frame rate and/or color fading of the transmitted image data. If power is deemed to be highly scarce (either due to poor wireless power coupling between auxiliary head unit  200  and IOMD implant  300 , or due to a depleted power source  205  in auxiliary head unit  200 ), then only monochromatic images with a low periodic frame rate (e.g., one frame every 2 seconds) are transmitted (process block  525 ). Referring to  FIG. 6 , image frame  603  is a fully monochromatic image. If more power is deemed available, then auxiliary controller  220  may transmit color images that fade to monochrome at the low periodic frame rate (process block  530 ). Referring to  FIG. 6 , auxiliary controller  220  may initially transmit a full-color image frame  601  that then fades to either a fully monochrome image frame  603  or a hybrid image frame  602 . Hybrid image frame  602  includes a multi-color center region  610  and a monochromatic peripheral region  605 . Multi-color center region  610  corresponds to the portion of the image frame that is projected onto the user&#39;s central foveal vision where acuity is highest. Monochromatic peripheral region  605  corresponds to the portion of the image frame that is projected onto the user&#39;s peripheral vision where acuity is diminished. Hybrid image frame  602  may also be referred to as a partially monochromatic image. If yet more power is deemed available, then auxiliary controller  220  may transmit hybrid image frames  602  with increasing frame rates (process block  535 ). If even more power is deemed available (or the user requests higher frame rate vision), then auxiliary controller  220  may transmit monochrome video at yet a higher frame rate (e.g., 5, 10, 20 frames/sec, or otherwise) (process block  540 ). Finally, if power is deemed to be plentiful, then full color, full frame rate (e.g., 20 or 30 frames/sec) video may be transmitted to IOMD implant  300 . 
     Accordingly, image quality may be adjusted by auxiliary controller  220  to regulate power consumption. The image quality can be adjusted by reducing/increasing frame rate of the image data, or the image quality may be adjusted by fading multi-color images into monochromatic images. This fading may be accomplished over time by fading between consecutively transmitted image frames (e.g., initially transmitting full-color image frame  601  then transitioning subsequently transmitted frames to either one of image frames  602  or  603 ). Additionally (or alternatively), fading may be accomplished within a given image frame by transmitting only hybrid image frames  602  that are multi-color in foveal region  610 , but monochromatic in peripheral region  605 . 
     The processes explained above are described in terms of computer software and hardware. The techniques described may constitute machine-executable instructions embodied within a tangible or non-transitory machine (e.g., computer) readable storage medium, that when executed by a machine will cause the machine to perform the operations described. Additionally, the processes may be embodied within hardware, such as an application specific integrated circuit (“ASIC”) or otherwise. 
     A tangible machine-readable storage medium includes any mechanism that provides (i.e., stores) information in a non-transitory form accessible by a machine (e.g., a computer, network device, personal digital assistant, manufacturing tool, any device with a set of one or more processors, etc.). For example, a machine-readable storage medium includes recordable/non-recordable media (e.g., read only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, etc.). 
     The above description of illustrated embodiments of the invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. 
     These modifications can be made to the invention in light of the above detailed description. The terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification. Rather, the scope of the invention is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation.