Independent voltage driving system for ocular stimulation with programmable contact control

Abstract

A method and system delivers customizable microcurrent stimulation to ocular tissue using a three half-bridge driver circuit. The system includes a control circuit that selectively switches high-side and low-side transistors, such as MOSFETs, to generate various electrical waveforms, such as stepped, asymmetric biphasic, pulsed, and triangular waveforms. These waveforms are applied to electrodes in contact with the eye for therapeutic treatment, addressing conditions like age-related macular degeneration (AMD) and other ocular disorders. The system allows for adjustments in amplitude, frequency, and duration of the waveforms, providing personalized treatment protocols tailored to patient-specific needs. High-impedance periods are included between pulses to promote tissue recovery and enhance patient comfort. Additionally, a non-transitory computer-readable storage medium stores a program that controls the system, enabling real-time waveform generation and dynamic adjustment during treatment. This approach offers a flexible and efficient solution for ocular therapy, improving both treatment outcomes and patient experience.

Description

[0001] INDEPENDENT VOLTAGE DRIVING SYSTEM FOR OCULAR

[0002] STIMULATION WITH PROGRAMMABLE CONTACT CONTROL

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS

[0004] This application claims priority to pending United States Provisional Application No. 63 / 651,790, filed on May 24, 2024, the contents of which are incorporated herein by reference. The application further claims priority to co-pending PCT applications PCT / US24 / 41736 and PCT / US24 / 41762, both of which were filed on August 9, 2024. The contents of both PCT applications are incorporated herein by reference.

[0005] STATEMENT RE: FEDERALLY SPONSORED RESEARCH / DEVELOPMENT

[0006] Not Applicable

[0007] BACKGROUND

[0008] 1. Technical Field

[0009] The present disclosure relates generally to treatment of dry Age-Related Macular Generation (AMD). The disclosure is more particularly directed to a system and method for treatment of dry AMD by ocular administration of microcurrent.

[0010] 2. Description of the Related Art

[0011] AMD is the leading cause of severe vision loss in North America. Moreover, its prevalence is expected to double over the next 20 years as baby boomers continue to age. More specifically, AMD is responsible for 8.7% of all blindness worldwide and is the most common cause of blindness in developed countries. Its prevalence increases with age and is therefore magnified by population ageing. AMD causes damage to the macula, the central part of the retina responsible for seeing details. There are two types of AMD: dry or atrophic; and wet or neo-vascular. Virtually all AMD begins in the dry form and according to the Canadian Ophthalmological Society, nine of ten people with AMD suffer from dry AMD.

[0012] Dry or atrophic AMD accounts for 85% of cases and is characterized by retinal pigmented epithelium dysfunction, and is a risk factor for, or even a precursor state of wet AMD, characterized by choroidal neovascularization. Geographic atrophy with loss of the retinal pigmented epithelium is accompanied by atrophy of adjacent photoreceptors and is a late stage of AMD. Dry AMD is debilitating with loss of ability to read, recognize faces, see signs while driving, producing greater life stress, lower activity levels, greater risk of depression, functional disability and also an associated increased risk of cognitive impairment. Risk factors for dry AMD include smoking, increasing age, higher serum cholesterol levels, and obesity. While treatment with vascular endothelial growth factor (VEGF) inhibitors is effective in wet AMD, presently there are no approved treatments for dry AMD.

[0013] A likelihood of an individual developing AMD is primarily determined by genetic predisposition, ethnicity, and health. If you are Caucasian, and your parents, grandparents or siblings have had AMD, you are at a substantially increased risk of developing the disease. Many studies have asserted that those with a history of smoking are also susceptible.

[0014] The understanding and treatment of dry AMD have evolved significantly over time, beginning with the anatomical identification of the macula in the mid- 19th century. Although the specific disease of AMD was not recognized initially, Dr. Otto Haab, a Swiss ophthalmologist, provided one of the earliest descriptions of what he called “senile macular disease” in older adults in the late 19th century. By the 1920s, "Senile Macular Degeneration" became a more commonly used term, and a distinction was made between the wet and dry forms of AMD, with dry AMD being more prevalent and less severe, characterized by drusen (yellow deposits under the retina) and changes in the retinal pigment epithelium.

[0015] The development of diagnostic tools such as fluorescein angiography from the 1960s to the 1980s allowed for better identification and differentiation of dry AMD from other retinal conditions, establishing drusen, geographic atrophy, and retinal pigment epithelium changes as hallmark features. The advent of optical coherence tomography (OCT) in the 1990s revolutionized the ability to visualize retinal layers in detail, enabling more precise and non-invasive monitoring of disease progression. Research into the pathophysiology of AMD during the 1990s and 2000s revealed that oxidative stress, inflammation, and lipid metabolism were key contributors to its development. Genetic studies highlighted the role of the complement system, with specific genes such as CFH (complement factor H) being implicated. In 2005, the Age-Related Eye Disease Study (AREDS) demonstrated that a combination of antioxidants (vitamins C and E), zinc, and beta-carotene could slow AMD progression in certain patients, though this regimen was more effective for intermediate or advanced stages and did not cure the disease or restore lost vision. The 2008 AREDS2 study refined these findings by testing additional nutrients, such as lutein, zeaxanthin, and omega-3 fatty acids, and concluded that substituting betacarotene with lutein and zeaxanthin was safer and equally effective in reducing the risk of advanced AMD. Despite these advancements, no FDA-approved therapies specifically for treating dry AMD beyond the AREDS / AREDS2 supplements exist. The focus has largely remained on lifestyle modifications, such as smoking cessation, dietary adjustments, and regular monitoring.

[0016] Emerging treatments like complement inhibitors, such as pegcetacoplan (tradename EMPAVELI - indicated for the treatment of paroxysmal nocturnal hemoglobinuria (PNH) in adults to reduce hemolysis and improve hemoglobin levels), have shown promise in slowing the progression of geographic atrophy in clinical trials. However, these treatments are not yet approved in countries such as the United States and Canada, where the standard approaches continues to emphasize AREDS / AREDS2 supplements and lifestyle changes.

[0017] Microcurrent therapy, also known as microcurrent stimulation (MCS) or microcurrent electrical stimulation (MES), is another treatment that has been explored for dry AMD. This therapy involves applying low-intensity electrical currents to specific areas around the eyes to improve cellular function and promote retinal health. It is believed that microcurrent may stimulate the mitochondria within retinal cells, enhancing energy production, reducing oxidative stress, and potentially slowing AMD progression.

[0018] Studies and case reports have suggested that microcurrent therapy can help stabilize or even improve vision in some patients by promoting the removal of drusen, reducing inflammation, or improving blood circulation in the retina and choroid. Drusen are formed from accumulation of waste materials and lipids (fatty proteins) between the retina and a layer called Bruch's membrane, which is just beneath the retinal pigment epithelium (RPE). These waste materials consist of cellular debris and byproducts that naturally occur from the metabolic processes of the retinal cells. Over time, the eye's ability to clear this waste diminishes, especially with aging or due to genetic factors, leading to the buildup of drusen. Factors such as oxidative stress, inflammation, and impaired clearance of cellular waste in the retina are believed to contribute to their formation.

[0019] Microcurrent therapy is available in Canada through certain specialized eye clinics or holistic health centers, although it is not considered a standard treatment and is not widely accessible. The therapy is typically administered at a healthcare provider location by an ophthalmologist or trained healthcare provider using small electrodes placed around the eyes or on specific acupuncture points near the eyes. Microcurrent therapy represents a non-invasive adjunctive approach to managing dry AMD.

[0020] Microcurrent treatments for conditions like dry AMD are typically applied in sessions that last about 15 to 45 minutes each. The frequency of these sessions can vary depending on the specific treatment protocol and the patient's response, but they are often administered two to three times per week initially.

[0021] Microcurrent treatments for conditions like dry AMD typically use very low- intensity electrical currents, usually in the range of 10 to 500 microamperes (pA). This level of current is much lower than what is used in conventional electrical stimulation therapies and is designed to be gentle enough not to cause discomfort or muscle contraction. The exact current level used can vary depending on the specific device, the treatment protocol, and the patient's individual needs. Most microcurrent devices allow for adjustments within this range to tailor the treatment to the patient’s tolerance and therapeutic response. The goal is to apply a current level that stimulates cellular repair and regeneration without causing any adverse effects.

[0022] For microcurrent treatments like those used for dry AMD, the voltage range is typically very low, usually between 1 to 20 volts (V). The voltage is kept low to ensure that the current remains at the microampere level (10 to 500 pA), which is gentle enough to avoid discomfort or any significant risk to the patient while still delivering therapeutic effects. A specific voltage applied can vary depending on the device and the treatment protocol, but it is controlled to provide just enough electrical potential to drive the desired microcurrent through the tissues without causing pain or adverse effects. After an initial period, which could range from several weeks to a few months, the frequency may be reduced to once a week or once every few weeks for maintenance. The overall duration of treatment can vary widely, with patients undergoing microcurrent therapy indefinitely, depending on individual conditions and observed benefits.

[0023] BRIEF SUMMARY

[0024] In accordance with an example embodiment of the present disclosure, a system and method for delivering microcurrent stimulation to ocular tissue uses a three halfbridge driver circuit. The system generates customizable electrical waveforms by selectively switching between high-side and low-side transistors to produce controlled electrical signals. These signals are applied to electrodes in contact with the eye, providing therapeutic microcurrent stimulation for ocular conditions.

[0025] The system is capable of generating various types of waveforms, including stepped, asymmetric biphasic, pulsed, and triangular waveforms, each tailored to meet specific treatment needs. The waveforms can be adjusted in terms of amplitude, frequency, and duration via a control interface, allowing for personalized treatment protocols based on patient requirements. The system also incorporates high-impedance periods between pulses to allow tissue recovery, optimizing both comfort and efficacy.

[0026] The system also includes a computer-readable storage medium that stores a program for controlling the system, enabling dynamic real-time control of the microcurrent treatment based on feedback from sensors or user inputs. The method and system offer a flexible, efficient, and customizable approach to ocular microcurrent stimulation therapy.

[0027] BRIEF DESCRIPTION OF THE DRAWINGS

[0028] These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which:

[0029] Figure 1 illustrates a block diagram of an example embodiment of an independent voltage driving system for ocular stimulation with programmable contact control; Figures 2A and 2B illustrate an example embodiment of a MCS treatment system 200, illustrated as a wearable headset;

[0030] Figure 3 illustrates a circuitry block diagram of an example embodiment of an independent voltage driving system for ocular stimulation;

[0031] Figure 4 illustrates an example embodiment of a three half-bridge driver circuit for wave generation in an optical MCS treatment system;

[0032] Figure 5 illustrates an example embodiment for generation of a square wave MCS treatment using a three half-bridge generator;

[0033] Figure 6 illustrates an example embodiment of a three half-bridge treatment wherein gate voltage inputs generate a treatment waveform with high-impedance periods;

[0034] Figure 7 illustrates an example embodiment of a three half-bridge treatment system using a stepped treatment waveform; and

[0035] Figure 8 illustrates an example embodiment of a three half-bridge system using a triangular or ramped treatment waveform

[0036] DETAILED DESCRIPTION

[0037] The detailed description set forth below in connection with the appended drawings is intended as a description of certain embodiments of a system and method for delivering microcurrent stimulation to ocular tissue uses a three half-bridge driver circuit, and is not intended to represent the only forms that may be developed or utilized. The description sets forth the various structure and / or functions in connection with the illustrated embodiments, but it is to be understood, however, that the same or equivalent structure and / or functions may be accomplished by different embodiments that are also intended to be encompassed within the scope of the present disclosure. It is further understood that the use of relational terms such as first and second, and the like are used solely to distinguish one entity from another without necessarily requiring or implying any actual such relationship or order between such entities.

[0038] Conventional MCS treatment circuitry is designed to deliver low-level electrical currents to specific areas, such as the eyes, to stimulate cellular activity, improve blood flow, and promote healing. For ocular treatments, the goal is to stimulate retinal cells and surrounding tissues to help manage conditions like dry AMD. The primary function of this circuitry is to generate and control the microurrents that are applied to the target tissues. The circuitry creates electrical signals, often in the form of pulses. These currents are kept at safe levels, typically in the microampere range, to avoid causing pain or damage to the tissues.

[0039] Overall, conventional MCS circuitry is designed to generate controlled, low- level electrical currents, adjust stimulation parameters to suit specific therapeutic needs, and deliver these currents safely through electrodes to the target tissues. The circuitry includes power management and safety features to ensure effective and safe treatment for conditions like dry AMD. Periodic waves, such as square waves, are used to quickly depolarize cells, while sine waves offer smoother, more comfortable delivery. Most conventional MCS circuits provide some level of adjustment for these stimulation parameters, such as intensity and frequency. These adjustments can be manual or programmable, allowing the treatment to be tailored to the patient's specific needs. Amplifiers boost the signal to a desired level, ensuring that the current is within a therapeutic range. A user interface allows the user to adjust these treatment parameters. Once the signal is modulated and amplified, it is sent to the output terminals connected to the electrodes on the patient’s body. The electrodes make contact with the skin around the eyes, allowing the microcurrent to flow through the tissues, while the circuit maintains a steady output to ensure consistent treatment.

[0040] Conventional MCS circuitry is driven from power received from power outlets. A bi-phasic treatment waveform may be obtained by the use of dual power supplies. Wall socket power typically provides alternating current (AC) which can be easily converted into both positive and negative direct current (DC) voltages using standard power supply components.

[0041] When using power from a wall socket, an AC -DC converter or power supply unit can be designed to convert the AC input (typically 110V or 220V, depending on the region) into both positive and negative DC outputs relative to a common ground. This is done through a process that includes rectification (converting AC to DC), filtering (removing ripples from the DC output), and regulation (stabilizing the DC voltage to the desired levels). Dual output power supplies can provide both a positive and a negative voltage, such as +5V and -5V, with respect to a shared ground. The circuitry interfaces with electrodes that deliver the current to the target area, such as eye pads or contact points around the eyes. It ensures a stable connection between the device and the body, managing resistance to ensure effective delivery of the therapeutic current.

[0042] Using power from an outlet for ocular MCS devices has several disadvantages. One major issue is safety. Devices that plug into an outlet are exposed to higher voltage levels, which can be dangerous if there is a malfunction, wiring problem, or damage to the device. A power surge or fault could lead to electrical shocks or burns, making these devices less safe, especially for use at home. Outlet-powered devices are also more susceptible to electromagnetic interference (EMI) from other electrical devices and fluctuations in the power supply. This interference can disrupt the precise delivery of electrical currents needed for effective treatment, potentially affecting the device's performance and reducing its therapeutic benefits. Electrical noise from household appliances or other sources can make it difficult to maintain consistent stimulation. Another disadvantage is reduced portability and flexibility. Being tethered to an electrical outlet limits where and how the device can be used, confining patients to areas near power sources. This lack of portability makes it inconvenient for daily use, especially if the patient needs to move around, travel, or use the device in various settings.

[0043] Additionally, devices that rely on outlet power often need extra components for power conversion and regulation, such as transformers and voltage regulators. These components add to the size, weight, and complexity of the device, making it bulkier and less comfortable to wear or use. The added complexity also increases the chances of component failure, which can reduce the reliability and lifespan of the device.

[0044] The need for a power outlet can also discourage regular use, which may reduce patient compliance with the treatment plan. If the device is inconvenient or cumbersome to set up and use, patients may be less likely to use it as prescribed, which can negatively affect treatment outcomes. Outlet-powered devices are also vulnerable to power supply issues, such as outages, surges, and fluctuations. These interruptions can disrupt therapy sessions, potentially reducing their effectiveness or causing discomfort. Power surges can even damage the device, leading to costly repairs or replacements.

[0045] Patients might also feel less safe and comfortable using a device that plugs into an outlet, due to concerns about electrical shocks or accidents and the need to stay close to a power source. This perception can lower their confidence in the device and reduce compliance with the treatment. Furthermore, the additional components needed for handling mains power can increase the cost of manufacturing and maintaining the device, making it more expensive in the long run.

[0046] Overall, while using power from an outlet provides a continuous power supply, it comes with significant drawbacks, including safety risks, interference issues, limited portability, increased size and complexity, and potential inconvenience for users. These factors can negatively impact the usability, safety, and effectiveness of the device, making battery-powered options generally more appealing for ocular MCS treatments.

[0047] A solution to the afore-noted concerns is to move to a battery powered system. Designing a battery-powered system for ocular MCS involves several challenges. One of the main challenges is the limited power capacity of batteries. Batteries can only store a finite amount of energy, which restricts how long the device can operate between charges. For MCS devices that need to deliver precise and continuous microcurrents, it can be difficult to ensure that the battery lasts long enough while keeping the device small and lightweight using conventional circuitry.

[0048] A device powered by a wall socket has a continuous power source that doesn’t require complex circuitry to generate separate positive and negative voltages, as would be needed with a battery setup. However, it is not well suited for battery power operation. Such would require a complex (more expensive, added weight) components like voltage inverters, DC-DC converters, or charge pumps to create a dual power supply from a single battery.

[0049] Maintaining consistent performance as the battery discharges is also a challenge. As a battery loses charge, its voltage can fluctuate, which can affect the performance of the MCS device. The circuitry needs to include components that regulate the voltage to ensure that the output current stays stable and within the desired therapeutic range, even when the battery's charge level drops. This often requires the use of efficient voltage regulators or converters that can handle changes in input voltage without using too much power.

[0050] Integrating all the necessary features for effective and safe MCS treatment — like real-time monitoring, feedback mechanisms, adjustable parameters, and wireless communication — into a battery-powered system makes the design more complex. Each feature uses power and may need additional circuitry, which has to be as power-efficient as possible. Balancing all these requirements while keeping the device compact, lightweight, and easy to use is a significant engineering challenge.

[0051] Overall, designing a battery-powered MCS system involves overcoming multiple challenges related to power management, size, and consistent performance, while also ensuring the device remains user-friendly and cost-effective.

[0052] Example embodiments herein address the above-noted concerns and provide a compact, reliable and battery powered MCS driver by employing three half-bridge drivers that can independently drive a high, low, or high-impedance value to apply a therapeutic current, such as via a square wave, to one or both eyes, suitably with a single common contact pad.

[0053] In electronics, a full bridge circuit (H-bridge) consists of four switches and allows for bidirectional control of current through a load, enabling both forward and reverse operation, which is ideal for applications like DC motor control or generating alternating current (AC) signals. In contrast, a half bridge circuit uses only two switches and can control current in one direction, typically between a high voltage, low voltage (ground), and a high-impedance state. A half-bridge driver is an electronic circuit used to control the flow of electrical current. It is called a "half-bridge" because it is made up of two switches, usually transistors, arranged in a specific way that forms one-half of a full bridge circuit. These switches are known as the "high-side" and "low-side" switches. They are connected in series between a positive voltage supply and ground, with their midpoint serving as the output that connects to the load. By controlling these two switches, the half-bridge driver can produce three different output states: high, low, or high-impedance. In the high state, the high-side switch is turned on while the low- side switch is off, allowing current to flow from the positive voltage supply to the load. In the low state, the low-side switch is on while the high-side switch is off, allowing current to flow from the load to ground. In the high-impedance state, both switches are turned off, resulting in no current flow through the load. This allows the circuit to control the direction of current flow through the load, making it ideal for creating alternating electrical fields for stimulation devices. Half-bridge drivers are efficient because the transistors used can switch on and off quickly, reducing power loss and heat generation. Example embodiments of the subject application employ three half-bridge drivers each able to drive the output to a common programmable voltage, battery negative, or high impedance (neither). Previous implementations drive positive and negative voltages with respect to a common face contact ground reference. In this implementation, the face contact may be driven to a programmable voltage while the eye contacts are driven to battery negative. This achieves an equivalent difference in potential with a simpler circuit with fewer components. It also allows for a current to be generated between the eye contacts without a current path to the face. Each of the three half-bridge drivers consist of a pair of semiconductor devices that connect the output lead to high, low, or neutral voltage potential.

[0054] The waveforms generated by a dual power supply design and a three half-bridge driver design differ in their method of creating and controlling the voltage levels for an ocular Microcurrent Stimulation (MCS) device. In a dual power supply design, the waveform is created using two separate power sources — a positive voltage supply and a negative voltage supply — relative to a common ground reference, often placed on the face. This setup allows the waveform to alternate directly between these two voltages, creating a transition from a positive voltage to a negative voltage and back. The waveform is centered around the common ground, meaning that each phase swings above or below this ground level. In contrast, the three half-bridge driver design uses a single power source, such as a battery, to create the waveform. Each of the three halfbridge drivers can independently control its output to a high voltage (programmable), a low voltage (battery negative), or a high-impedance state, where no voltage is applied. This design does not require two separate power supplies. Instead, it can adjust which contact is at a high voltage, low voltage, or disconnected (high-impedance), allowing for more customized and flexible waveforms.

[0055] A dual power supply waveform typically looks like a standard square or sine wave that alternates symmetrically around a central zero line, which is the common ground. Each positive phase is followed directly by a negative phase, producing a clear and predictable pattern of stimulation, with direct transitions between positive and negative voltages based on the timing set by the circuit. In the three half-bridge driver design, the waveform can be more varied and complex. Since each half-bridge can independently control the voltage or be set to a high-impedance state, the transitions can include not only shifts between high and low voltages but also moments where the output is disconnected. This results in a waveform that may include pauses, varying phase lengths, and different amplitudes, allowing greater flexibility in how the stimulation is delivered.

[0056] The dual power supply design offers straightforward control but with less flexibility, as it relies on switching between two fixed voltages set by the power supplies, without the ability to dynamically adjust the pattern or introduce safety features like high-impedance states. In contrast, the three half-bridge design offers more control and safety by generating a wider variety of waveforms, adjusting each output independently to different voltage states. This flexibility improves safety by allowing parts of the circuit to be isolated to prevent unintended currents, and it enables more tailored treatment patterns for specific therapeutic needs. The dual power supply design depends heavily on a common ground to create the necessary potential differences for stimulation, producing a waveform that is always symmetrical around this ground reference. The three half-bridge driver design, however, does not rely on a common ground in the same way. Instead, it uses independent control over each contact point to establish the required potential differences, referencing a programmable voltage or battery negative. This approach offers more options for directing stimulation currents and creates a more versatile stimulation pattern.

[0057] Figure 1 illustrates a block diagram 100 of an example embodiment of an independent voltage driving system for ocular stimulation with programmable contact control. The block diagram represents an ocular Microcurrent Stimulation (MCS) controller that uses three half-bridge drivers for delivering precise electrical stimulation to the eyes. Microcontroller 104 is a central control unit of the MCS device. It functions to generate control signals, execute the treatment protocols, and adjust treatment parameters based on real-time feedback. Microcontroller 104 takes input from feedback sensors 108 and processes this information to ensure that the correct electrical stimulation patterns are delivered. It also communicates with other components, such as Pulse Width Modulation (PWM) generator 112, to control output treatment signals.

[0058] PWM generator 112 creates a pulse width modulation signals used to control three half-bridge drivers 116. PWM is used to regulate voltage levels applied to the electrodes by rapidly switching the drivers on and off at specific frequencies and duty cycles. Microcontroller 104 instructs the PWM generator to adjust these parameters to achieve the desired waveform characteristics, such as amplitude, frequency, and duration, for effective ocular therapy.

[0059] Three half-bridge drivers 116 manage the delivery of electrical currents to electrode contacts 120 placed on a patient eyes. Each half-bridge driver consists of two semiconductor switches, which can independently connect their output to a high voltage, a low voltage (such as battery negative), or a high-impedance state (disconnected). By dynamically controlling these drivers, the device can create various stimulation patterns, including complex waveforms that are optimized for different therapeutic needs. The half-bridge drivers are controlled by the signals from PWM generator to ensure the precise delivery of electrical pulses to the eye contacts.

[0060] Power supply 124 provides electrical power for all components in the MCS device, including microcontroller 104, PWM generator 112, and half-bridge drivers 116. It supplies a stable voltage to ensure consistent performance of the electronic circuitry. The power supply may be a single battery or an external source, and it provides the high and low voltages needed to create the appropriate potential differences for stimulation.

[0061] Feedback sensor 108 monitors various parameters, such as resistance between electrodes, contact quality, and other suitably physiological responses. The feedback sensor continuously provides data to microcontroller 104, allowing it to adjust the output in real-time. For example, if the contact resistance changes due to movement or moisture, microcontroller 104 can modify the PWM signals to maintain the correct stimulation levels, ensuring both safety and effectiveness.

[0062] Electrode contacts 120 are points where the electrical currents are delivered to the patient’s eyes. The contacts are connected to the outputs of three half-bridge drivers 116, and they apply electrical pulses generated by the drivers to the targeted areas. The precise control over the voltage levels and timing at the electrode contacts is crucial for optimizing the therapeutic effects while minimizing discomfort or potential harm to the delicate tissues of the eye.

[0063] Figures 2A and 2B illustrates an example embodiment of a MCS treatment system 200, illustrated as a wearable headset. Treatments with examples of this electrical stimulation system 200 are not invasive and do not involve drugs. The microcurrent therapy employed by these examples of electrical stimulation system 200 are comparable to a modern-day TENS device in terms of being harmless to a patient.

[0064] More specifically, microcurrent provides electrical stimulation to nerve fibers through cutaneous electrodes, using lower current than transcutaneous electrical nerve stimulation (TENS). Microcurrent is best known for skin healing with reduction of inflammation, improved local blood circulation, and improved mitochondrial function, and has even recently been adapted for direct cardiac application to improve reduced ejection fraction heart failure. Wound healing is improved by microcurrent energy through alterations in cell metabolism, changes in extracellular matrix and pro- inflammatory signals. Animal studies of transpalpebral electrical stimulation demonstrated a positive signal, preventing photoreceptor loss and improving retinal function, as well as stimulating Muller cells toward neuroregeneration and repair. A study of human volunteers found a microcurrent effect on ganglion cells that was polarity-dependent. In twenty-eight patients with planned vitrectomy, thirteen received microcurrent pre-operatively. In treatment patients, positive effects were demonstrated on retinal cell function and survival, and reduced proinflammatory cytokines (IL-6, IL- 8), and reduced bioactive lipid mediator expression (lysophosphatidylcholine), compared to 15 patients who did not receive microcurrent. An early study demonstrated that transpalpebral microstimulation could be safely administered to patients with dry AMD, treating 25 eyes in seventeen patients receiving two to ten weekly treatments, finding improvement in visual acuity in 52% of eyes.

[0065] In other words, an electro-therapeutic electrical stimulation system 200 in accordance with examples of this technology employs very small doses of electrical energy (microcurrent) to: slow the progression in early-stage AMD, and revitalize macular structures & significantly restore vision in advanced AMD. Treatment is painless and takes only minutes. Extensive studies have demonstrated the treatment to be completely safe. The electrical stimulation system 200 in accordance with example of this technology can be portable (along with a carrying case), and be battery operated or rechargeable (e.g., with 30 treatments per charge). It can have convenient, easily accessible device controls, low-weight (e.g., 0.45 kg), and easy to clean and maintain.

[0066] Microcurrent therapy that utilize wavelengths and microcurrent waveforms applied to injured tissue increases the total current in the diseased region and restores natural responses and characteristics for cells and tissue to regain and maintain their viability. Retinal cells that were considered dead are not dead, but are in a toxic dormant state and are revived with microcurrent therapy. Current science has shown that when microcurrent therapy is applied, damaged retinal blood vessels become more absorptive and adenosine triphosphate (ATP) production / release occurs, promoting enhanced vision in patients with macular degeneration (AMD). Examples of this technology utilize a regimen of microcurrent therapy applied at wavelengths and microcurrent waveforms that stimulate retinal blood flow and electrical cellular response to achieve maximal visual acuity improvement.

[0067] In an example treatment, each procedure takes approximately 32 minutes, and includes a 40-cycle treatment of microcurrent stimulation applied to four sites around the eyes (upper left lid, lower left lid, upper right lid and lower right lid) for 40 seconds at each location, simultaneously.

[0068] With each trial subject, significant restored vision can be achieved with the first approximately 30-minute treatment. For example, a patient can expect to go from 20 / 200 vision to 20 / 40 vision in 3 weeks using the electrical stimulation system 200 in accordance with examples of this technology.

[0069] The electrical stimulation system 200 in accordance with examples of this technology can have one-time or multiple-time eyecup electrode adjustment. Conductive gel can be provided on skin around the eyes and / or on eyecup electrodes 214(1) and 214(2), and to the headset's conductive face pads 216. The electrical stimulation system 200 in accordance with examples of this technology is placed on a patient's head. When ready for treatment, the patient presses a start button to begin a preset treatment.

[0070] The electrical stimulation system 200 in accordance with an example of this technology includes wearable headset 204 and an AC-powered operated signal generator 90 that provides a pulsed microcurrent waveform output with a default varying frequency pattern from 1 - 50 Hz and a settable current level between 50 - 200 pA. This signal is fed to the headset 204 comprising two independent eyecup electrodes 214(1) and 214(2), which deliver current to the eye (with the eyelid closed). In an example, the current completes a circuit through the conductive face pads 216 (using, for example, conductive fibers or mesh embedded in the face pads 216) which are in electrical contact with the patient’s face and / or forehead, while the headset 204 is worn by the patient. Compression of the face pads 216 to the face / forehead is accomplished by, for example, elastic straps 208 of the headset 204. This configuration ensures that the electrical contacts of the face pads 216 are held tightly against the face / forehead. Other configurations for completing the current path are possible such as by doing so in an eye-to-eye manner, e.g., by not using the face pads 216 as an electrical conduit. Signal parameters, timing, and auditory feedback control operations are controlled by a microprocessor (not shown) housed in a control unit (also not shown) which itself may be housed in the face module 212 (of the headset 204) or another part of the headset 204. Although the signal generator 224 is shown in FIG. 2A as being separate from the headset 204, it may alternatively be incorporated into any part of headset 204 including within or attached to the face module 212. An optional face module cover 220 may be raised or lowered from the face module 212 and may provide access to the components (e.g., the control unit if housed in the face module 212, and eyecup electrodes 214(1) and 214(2)) within the face module 212.

[0071] Each of the eyecup electrodes 214(1) and 214(2) is coupled to the signal generator 224 and configured to contact and deliver the microcurrent waveform to the skin surface (such as eyelids) within an eye region of a patient. In examples described herein, the first position is a calibration position used when the headset 204 is worn, or not worn, by the patient and allows for positioning or repositioning of each of the eyecup electrodes 214(1) and 214(2) on the platform 228 by a user (i.e., the patient, or other person such as a helper / assistant). Eyecup electrode platform assembly 226 comprises a platform 228 that enables each of the eyecup electrodes 214(1) and 214(2) to be movably and removably coupled (via, for example, a magnet).

[0072] The microcurrent generation in examples of this disclosure may employ the types described in U.S. Patent Nos. 10,456,579 (issued to Salazar), 11,007,367 (issued to O'Clock), or 11,896,827 (issued to O'Clock) which are herein incorporated by reference. Other aspects of the electrical stimulation system 200 (or microcurrent device), including methods therefor, disclosed in these patents may be employed in any of the examples of this disclosure and which are also all herein incorporated by reference. An example MCS treatment prescription may include device parameter configuration settings such as provided in the table below.

[0073] Figure 3 illustrates a circuitry block diagram 300 of an example embodiment of an independent voltage driving system for ocular stimulation suitably used in connection with a treatment headset. Included is agitator circuitry 304 which includes a three half-bridge driver system for generating waves for ocular MCS application, such as with the MCS treatment headset detailed in connection with Figures 2A and 2B. It is to be appreciated that agitator, as used herein, refers to a component or mechanism that delivers controlled microcurrent pulses or patterns to stimulate the ocular tissues, such as the retina, optic nerve, or surrounding cells. Controlled electrical stimulation agitates or activates the target cells and tissues through electrical impulses. System power is suitably provide by battery charger and power system 308. Also illustrated is a user input 312, suitably comprised of membrane switches to allow for user interaction and control for ocular MCS treatment. User feedback module 316 suitably provides audible or haptic feedback to users undergoing treatment. Non-visual feedback is advantageous given that users may already be visually impaired, as well a rendered incapable of seeing anything whatsoever while wearing a headset during treatment. Processing is accomplished by processor module 320, comprised of any suitable controller or microcontroller as will be understood by one of ordinary skill in the art Figure 4 illustrates an example embodiment of a three half-bridge driver circuit 400 for wave generation in an optical MCS treatment system, suitably formed within agitator circuitry 304 of Figure 3. The half-bridge driver circuit is suitably formed transistors such as by the use of transistors, such as N-channel MOSFETS 404, 408 and 412. MOSFETs are suited for ocular MCS systems due to their fast switching speed, low power consumption, and high efficiency, which enable precise control of therapeutic waveforms while minimizing energy loss and heat generation. Their high input impedance and voltage-controlled operation simplify the control circuitry, making them easy to interface with microcontrollers. Additionally, MOSFETs can handle high currents and voltages, are highly efficient, and come in compact sizes, making them suited for portable, battery-powered medical devices where space and power efficiency are critical.

[0074] N-channel MOSFET provide for switching and amplifying electronic signals and include an ability to conduct current when a positive voltage is applied to a gate terminal relative to a source terminal. In the illustrated example, a SI1029X-T1-GE3 N-channel MOSFET, manufactured by Visha Intertechnology, Inc., is utilized given its design for efficient power switching with features such as a low on-resistance of 0.008 Q, high current handling capability of 4.5 A, and low gate charge for fast switching. It is housed in a compact SOT-23 package and supports logic-level gate drive, making it suitable for use in power management, load switching, and battery-power providing high efficiency and small size for use in an ocular MCS treatment headset.

[0075] Each of N-channel MOSFETS 404, 408 and 412 include connections PG, NG, PD, ND, PS and SN. In the example embodiment of a three half-bridge driver circuit using three SI1029X-T1-GE3 MOSFETs for an ocular Microcurrent Stimulation (MCS) device, the terms PG, NG, PD, ND, PS, and SN refer to different points where these MOSFETs are connected and controlled. PG (Positive Gate) represents the gate input of the MOSFET that receives a positive voltage signal to turn on the high-side MOSFET, allowing current to flow from the positive voltage supply to the output. NG (Negative Gate) refers to the gate input that controls the low-side MOSFET, which is turned off when a lower voltage (near ground) is applied; when this MOSFET is on, it connects the output to ground. PD (Positive Drain) refers to the drain terminal of the high-side MOSFET, which is connected to the positive voltage supply and allows current to flow to the load when the MOSFET is on. ND (Negative Drain) denotes the drain terminal of the low- side MOSFET, which connects to the output when turned on, allowing current to flow from the load back to ground. PS (Positive Source) typically represents the source terminal of the high-side MOSFET, which is connected to the output node and the positive supply when the MOSFET is turned on. SN (Source Negative or Source Ground) refers to the source terminal of the low-side MOSFET, which is tied to ground.

[0076] By controlling the PG and NG inputs, the circuit switches the MOSFETs to direct current flow and create the desired electrical stimulation waveforms for the ocular MCS device. The three half-bridge driver circuit, using MOSFETs like the SI1029X-T1-GE3, shapes the treatment waveform in an ocular Microcurrent Stimulation (MCS) device by controlling how electrical currents are delivered to the eye. This circuit allows precise switching between different voltage states — high, low, and high-impedance — at its outputs, which determines the pattern, timing, and strength of the microcurrent stimulation applied.

[0077] Each half-bridge in the circuit has two MOSFETs: a high-side MOSFET that connects the output to a positive voltage and a low-side MOSFET that connects the output to ground. The circuit controls which MOSFETs are on or off using the gate signals: PG (Positive Gate) to turn on the high-side MOSFET and NG (Negative Gate) to turn on the low-side MOSFET. By selectively turning these MOSFETs on or off, the circuit can switch the output between a high voltage, a low voltage, or leave it in a high- impedance state where it is not connected to either

[0078] This capability allows the circuit to create different types of waveforms needed for MCS treatment. For a biphasic waveform, the circuit alternates between turning on the high-side MOSFET to send a positive voltage and then the low-side MOSFET to connect the output to ground. This creates a pattern where the current flows first in one direction and then the other, which is useful for stimulating retinal cells. A monophasic waveform can be created by only using one state, like repeatedly connecting the output to a positive voltage while occasionally switching to a high-impedance state to provide a rest period. The circuit can adjust the amplitude, frequency, and duration of the waveforms by controlling how long each MOSFET is on or off. For example, keeping the high- side MOSFET on for a longer period extends the positive phase of the waveform, while adjusting the frequency of switching determines how fast the waveform alternates. Additionally, the circuit can introduce high-impedance periods by turning both MOSFETs off, allowing for breaks in the stimulation that help prevent overstimulation and give tissues time to recover.

[0079] Overall, the three half-bridge driver circuit provides a flexible way to generate various waveform shapes, such as square, triangular, or pulsed patterns, which can be customized to meet different therapeutic needs. This flexibility is important for optimizing the treatment according to the specific condition being treated, the patient's needs, and the desired therapeutic outcomes.

[0080] Figure 5 illustrates an example embodiment for generation of a square wave MCS treatment 500 using a three half-bridge generator. The square wave, which alternates between positive and negative voltages, is one of the simplest and most commonly used waveforms in microcurrent stimulation. Application of the illustrated gate voltages 504 to the three half-bridge system result in the illustrated output voltage square wave 508. Various treatment waveforms, such as the square wave, are suitably generated in conjunction with a microcontroller. GPIO (General -Purpose Input / Output) pins are flexible digital signal pins on a microcontroller or microprocessor that can be configured as either input or output. They are used to interface with the subject three half-bridge system. In the context of pseudocode for the three half-bridge driver circuit generating treatment waveforms, the GPIO pins control the High-Side and Low-Side MOSFET gates. These GPIO pins are set to output mode and are programmed to turn the MOSFETs on or off at the right times to create the desired waveforms. An example embodiment of microcontroller pseudocode to generate a square waveform follows:

[0081] BEGIN

[0082] INITIALIZE GPIO pins for High-Side and Low-Side MOSFETs

[0083] SET timer to control the period for positive and negative square wave phases

[0084] LOOP / / Positive Phase

[0085] TURN ON High-Side MOSFET

[0086] TURN OFF Low-Side MOSFET

[0087] WAIT for half period (positive half of the wave)

[0088] / / Negative Phase

[0089] TURN OFF High-Side MOSFET

[0090] TURN ON Low-Side MOSFET

[0091] WAIT for half period (negative half of the wave)

[0092] / / Repeat cycle

[0093] END LOOP

[0094] END

[0095] The square waveform delivers sharp transitions between high and low voltages, which can effectively stimulate the retina or other tissues. The square wave’s straightforward and repetitive nature makes it a reliable option for general ocular treatments, where a steady and consistent stimulation is required to achieve therapeutic results. It is frequently used in MCS devices for its ease of control and predictable effects.

[0096] Figure 6 illustrates an example embodiment of a three half-bridge treatment wherein gate voltage inputs generate a treatment waveform 600 with high-impedance periods. Application of the illustrated gate voltages 604 to the three half-bridge system result in the illustrated output wave 608. An example embodiment of microcontroller pseudocode to generate this waveform follows:

[0097] BEGIN

[0098] INITIALIZE GPIO pins for High-Side and Low-Side MOSFETs

[0099] SET timer to control pulse and high-impedance durations

[0100] LOOP

[0101] / / Positive Pulse

[0102] TURN ON High-Side MOSFET

[0103] TURN OFF Low-Side MOSFET

[0104] WAIT for pulse duration / / High-Impedance Period (No current)

[0105] TURN OFF both High-Side and Low-Side MOSFETs

[0106] WAIT for high-impedance period duration

[0107] / / Negative Pulse

[0108] TURN OFF High-Side MOSFET

[0109] TURN ON Low-Side MOSFET

[0110] WAIT for pulse duration

[0111] / / High-Impedance Period (No current)

[0112] TURN OFF both High-Side and Low-Side MOSFETs

[0113] WAIT for high-impedance period duration

[0114] / / Repeat cycle

[0115] END LOOP

[0116] END

[0117] This waveform consists of distinct pulses separated by high-impedance periods where no current flows. The pulsed pattern allows for bursts of stimulation followed by rest periods, which can help in avoiding muscle or nerve fatigue. The high-impedance periods ensure that the tissue has time to recover between pulses, which may improve comfort and safety. This type of waveform may be useful in situations where short, intense bursts of stimulation are needed to activate certain biological processes or where prolonged stimulation could cause irritation or damage. Pulsed waveforms with high- impedance periods might be used to maximize the therapeutic benefits of electrical stimulation while minimizing potential side effects.

[0118] Figure 7 illustrates an example embodiment of a three half-bridge treatment system using a stepped treatment waveform 700. Application of the illustrated gate voltages 704 to the three half-bridge system result in the illustrated output wave 708. An example embodiment of microcontroller pseudocode to accomplish generation of a stepped treatment waveform is as follows:

[0119] BEGIN

[0120] INITIALIZE GPIO pins for High-Side and Low-Side MOSFETs SET timer to control step duration LOOP

[0121] / / Step 1 : Low voltage

[0122] TURN ON Low-Side MOSFET

[0123] TURN OFF High-Side MOSFET

[0124] WAIT for step duration

[0125] / / Step 2: Medium voltage

[0126] TURN OFF Low-Side MOSFET

[0127] TURN ON High-Side MOSFET

[0128] WAIT for step duration

[0129] / / Step 3 : High-impedance (no current)

[0130] TURN OFF both High-Side and Low-Side MOSFETs

[0131] WAIT for step duration

[0132] / / Step 4: Medium voltage, reverse direction

[0133] TURN ON Low-Side MOSFET

[0134] TURN OFF High-Side MOSFET

[0135] WAIT for step duration

[0136] / / Step 5 : High-impedance (no current)

[0137] TURN OFF both High-Side and Low-Side MOSFETs

[0138] WAIT for step duration

[0139] / / Repeat steps

[0140] END LOOP

[0141] END

[0142] The stepped waveform provides a gradual, controlled pattern of electrical stimulation that helps prevent adaptation, controls the dose of stimulation, targets different retinal cells, enhances blood flow, aids in sensory training, and allows for highly customizable treatment protocols. These characteristics make it particularly useful for a range of ocular conditions, including retinal degenerative diseases, ischemic retinopathies, and conditions involving abnormal sensory processing or retinal sensitivity. The alternative stepped treatment waveform is designed to provide a more controlled and gradual pattern of electrical stimulation. It ramps up and down in distinct steps, with high-impedance periods in between, which prevents overstimulation and helps the retinal cells remain responsive. This waveform is particularly useful for avoiding adaptation, where the tissue becomes less sensitive to continuous stimulation. By adjusting the voltage in steps, it allows precise control over the amount of energy delivered, making it suitable for conditions like Age-Related Macular Degeneration (AMD) or diabetic retinopathy. Additionally, the gradual increase in stimulation can target different types of retinal cells and improve blood flow to the area.

[0143] The pulsed waveform with high-impedance periods provides short bursts of electrical stimulation followed by high-impedance rest periods. This approach helps to prevent muscle or tissue fatigue by allowing recovery between pulses. The pulsed nature of the waveform can maximize the therapeutic effect while minimizing discomfort or overstimulation. It is particularly useful in situations where brief, intense stimulation is needed without causing irritation or long-term damage to the tissue

[0144] Figure 8 illustrates an example embodiment of a three half-bridge system using a triangular or ramped treatment waveform. Application of the illustrated gate voltages 804 to the three half-bridge system result in the illustrated output wave 808. This waveform gradually ramps up and down in voltage, creating a smooth, continuous transition between high and low levels. An example embodiment of pseudocode to generate this waveform follows:

[0145] BEGIN

[0146] INITIALIZE GPIO pins for High-Side and Low-Side MOSFETs

[0147] SET timer to control ramp intervals

[0148] SET step increment for ramping the voltage

[0149] SET max voltage and min voltage

[0150] / / Start with both MOSFETs OFF (high-impedance state)

[0151] TURN OFF High-Side MOSFET

[0152] TURN OFF Low-Side MOSFET

[0153] LOOP

[0154] / / Ramping up the voltage

[0155] FOR voltage = min voltage TO max voltage STEP step increment

[0156] / / Apply positive ramp by turning on High- Side MOSFET

[0157] TURN ON High-Side MOSFET SET duty cycle proportional to voltage

[0158] WAIT for ramp interval

[0159] END FOR

[0160] / / High-Impedance state

[0161] TURN OFF High-Side MOSFET

[0162] TURN OFF Low-Side MOSFET

[0163] WAIT for recovery period

[0164] / / Ramping down the voltage

[0165] FOR voltage = max voltage TO min voltage STEP step increment

[0166] / / Apply negative ramp by turning on Low-Side MOSFET

[0167] TURN ON Low-Side MOSFET

[0168] SET duty cycle proportional to voltage

[0169] WAIT for ramp interval

[0170] END FOR

[0171] / / High-Impedance state

[0172] TURN OFF High-Side MOSFET

[0173] TURN OFF Low-Side MOSFET

[0174] WAIT for recovery period

[0175] / / Repeat cycle

[0176] END LOOP

[0177] END

[0178] The triangular waveform is less abrupt than a square waveform, which can make it more comfortable for patients, particularly for those who may be sensitive to sharp transitions. The high-impedance pauses allow the circuit to effectively "disconnect" at intervals, reducing the total energy delivered over time and providing recovery periods for the tissue being stimulated. This can be beneficial for therapies that aim to promote gentle stimulation and reduce the risk of overstimulation or tissue fatigue. The triangular waveform might be used to encourage gradual cellular responses or to optimize conditions where slow, controlled stimulation is needed.

[0179] In further example embodiments, the three half-bridge driver circuit is suitably implemented with enhancements that improve the system’s precision, efficiency, and adaptability. In these embodiments, the resolution of the switching control is increased, enabling finer adjustments of voltage levels and smoother transitions between states, thereby improving the accuracy of waveform generation and the effectiveness of microcurrent stimulation. The is suitably accomplishes this with programmable logic controllers (PLCs) or field-programmable gate arrays (FPGAs) to dynamically control the timing and sequencing of the half-bridge drivers, facilitating real-time adjustments to the waveform based on patient-specific feedback or pre-programmed treatment protocols.

[0180] Further example embodiments suitably implement adaptive control algorithms that adjust the switching behavior in response to real-time changes in electrode-tissue impedance, ensuring that the delivered waveform remains consistent and optimal throughout the treatment. The circuit incorporates synchronous rectification, replacing traditional diodes with MOSFETs or other low-loss components, which reduces power losses and enhances system efficiency by extending battery life and minimizing heat generation. In certain embodiments, advanced gate driver ICs are employed, featuring dead-time control, shoot-through protection, and overcurrent protection, providing increased reliability and safety in the operation of the half-bridge drivers.

[0181] In additional example embodiments, a multi-level half-bridge design is implemented, providing finer control over voltage levels and ensuring smoother transitions between waveform states, reducing electrical noise and improving waveform precision. These example embodiments may suitably include currentsensing capabilities integrated within each half-bridge driver, allowing for real-time monitoring and regulation of the current delivered to ocular tissue to ensure safety and efficacy during treatment. An example embodiment of microcontroller pseudocode for a multi-level half-bridge design follows:

[0182] BEGIN

[0183] INITIALIZE GPIO pins for controlling each level of the multi-level halfbridge drivers

[0184] INITIALIZE control parameters for voltage levels (e.g., Levell, Level2, etc.) INITIALIZE timer to control switching intervals

[0185] SET max voltage and min voltage for the waveform / / Begin treatment loop

[0186] WHILE treatment session active:

[0187] / / Ramping Up: Gradually increase voltage to max level

[0188] FOR voltage level = min voltage TO max voltage STEP voltage increment:

[0189] IF voltage level == Level 1:

[0190] TURN ON MOSFET Levell

[0191] TURN OFF MOSFET_Level2, Level3, Level4

[0192] ELSE IF voltage level == Level2:

[0193] TURN ON MOSFET_Level2

[0194] TURN OFF MOSFET Levell, Level3, Level4

[0195] ELSE IF voltage level == Level3:

[0196] TURN ON MOSFET_Level3

[0197] TURN OFF MOSFET Levell, Level2, Level4

[0198] ELSE IF voltage level == Level4:

[0199] TURN ON MOSFET_Level4

[0200] TURN OFF MOSFET Levell, Level2, Level3

[0201] END IF

[0202] WAIT for ramping interval

[0203] END FOR

[0204] / / High-Impedance Period (No current flow)

[0205] TURN OFF all MOSFETs (Levell, Level2, Level3, Level4)

[0206] WAIT for recovery interval

[0207] / / Ramping Down: Gradually decrease voltage to min level

[0208] FOR voltage level = max voltage TO min voltage STEP voltage decrement:

[0209] IF voltage level == Level4:

[0210] TURN ON MOSFET_Level4

[0211] TURN OFF MOSFET Levell, Level2, Level3

[0212] ELSE IF voltage level == Level3:

[0213] TURN ON MOSFET_Level3 TURN OFF MOSFET Levell, Level2, Level4

[0214] ELSE IF voltage level == Level2:

[0215] TURN ON MOSFET_Level2

[0216] TURN OFF MOSFET Levell, Level3, Level4

[0217] ELSE IF voltage level == Level 1 :

[0218] TURN ON MOSFET Levell

[0219] TURN OFF MOSFET_Level2, Level3, Level4

[0220] END IF

[0221] WAIT for ramping interval

[0222] END FOR

[0223] / / High-Impedance Period (No current flow)

[0224] TURN OFF all MOSFETs (Levell, Level2, Level3, Level4)

[0225] WAIT for recovery interval

[0226] / / Check for patient feedback or external signals to adjust the waveform

[0227] IF feedback signal detected:

[0228] ADJUST treatment parameters (amplitude, frequency, duration)

[0229] / / Optional: End treatment session based on timer or condition

[0230] IF treatment time expired:

[0231] BREAK loop

[0232] END WHILE

[0233] / / Turn off all MOSFETs and safely end the treatment session

[0234] TURN OFF all MOSFETs (Levell, Level2, Level3, Level4)

[0235] END session

[0236] END

[0237] The pseudocode is designed to control an ocular microcurrent stimulation (MCS) system that uses a multi-level half-bridge architecture, allowing for more refined voltage control and smoother waveform generation. The microcontroller is responsible for managing multiple MOSFETs, each tied to a specific voltage level (e.g., Levell for the lowest voltage and Level4 for the highest). The system begins by initializing the necessary GPIO pins to control these MOSFETs, as well as setting up the control parameters for voltage levels, ramping intervals, and the session’s duration. The process starts with the ramping up of the voltage, where the microcontroller gradually increases the voltage from a minimum level to the maximum by sequentially turning on the relevant MOSFETs. For example, at the lowest level, only the MOSFET controlling Level 1 is turned on, while the others are off. As the voltage increases, the MOSFET for Level 1 turns off, and the MOSFET for Level2 turns on, and so on until the maximum voltage is reached at Level4.

[0238] Once the voltage reaches the maximum level, the system transitions into a high- impedance period, where all MOSFETs are turned off to prevent current flow. This rest phase allows the ocular tissue to recover from the stimulation before the next phase. After the high-impedance period, the system begins ramping down the voltage. The process mirrors the ramp-up phase, but in reverse order. The microcontroller decreases the voltage gradually by sequentially turning off the MOSFETs in descending order of voltage levels, starting from Level4 and stepping down to Level 1. This smooth ramping down provides a controlled decrease in stimulation.

[0239] During both ramp-up and ramp-down phases, real-time feedback is continuously monitored. The system checks for feedback signals, such as changes in impedance or patient input, which can trigger adjustments to the treatment parameters, including the amplitude, frequency, or duration of the waveform. This feedback mechanism allows the system to dynamically optimize the stimulation based on the patient’s real-time response, ensuring both safety and therapeutic effectiveness.

[0240] Throughout the treatment, high-impedance periods are interspersed between ramping phases to prevent overstimulation and allow for recovery. The treatment session continues as long as it remains active, based on the predefined conditions or until a timer expires. If a feedback signal or condition is detected that requires the session to end, the microcontroller will safely terminate the treatment by turning off all MOSFETs.

[0241] Overall, this detailed control of the multi-level half-bridge system provides precise waveform generation with smoother voltage transitions, minimizing electrical noise and improving the effectiveness of the microcurrent stimulation. By leveraging real-time feedback, high-impedance recovery periods, and dynamic voltage control, the system offers a highly adaptable and effective approach to ocular therapy. Higher-frequency switching is also suitably used in further example embodiments, leveraging advanced transistors, such as GaN, to achieve greater waveform precision and enable the generation of higher-frequency therapeutic signals.

[0242] Other example embodiments suitably include active load balancing among the half-bridge drivers to ensure even distribution of electrical loads, extending the lifespan of system components and improving the reliability of waveform generation. Additionally, low-energy operating modes are implemented in these embodiments, reducing power consumption during high-impedance periods or during lower power phases of the treatment waveform, optimizing the system’s overall energy efficiency for long-term use, particularly in portable or battery-operated devices. These further embodiments provide significant enhancements to the three half-bridge driver circuit, ensuring superior performance, safety, and adaptability in delivering ocular microcurrent stimulation.

[0243] The particulars shown herein are by way of example only for purposes of illustrative discussion, and are not presented in the cause of providing what is believed to be most useful and readily understood description of the principles and conceptual aspects of the various embodiments of the present disclosure. In this regard, no attempt is made to show any more detail than is necessary for a fundamental understanding of the different features of the various embodiments, the description taken with the drawings making apparent to those skilled in the art how these may be implemented in practice.

Claims

WHAT IS CLAIMED IS:

1. An apparatus for delivering microcurrent stimulation to ocular tissue, comprising: a power supply; a plurality of half-bridge drivers, each half-bridge driver comprising a high-side transistor and a low-side transistor; a control circuit configured to selectively control the gates of the high-side and low-side transistors to deliver a first voltage, a second voltage, and a high-impedance state to the output terminals; wherein the output terminals are configured to connect to electrodes positioned on or near ocular tissue to deliver electrical stimulation in a controlled waveform.

2. The apparatus of claim 1, wherein the control circuit is configured to generate a stepped voltage waveform by sequentially switching between different voltage levels using the high-side and low-side transistors comprised of MOSFETs.

3. The apparatus of claim 1, wherein the control circuit is configured to generate a stepped voltage waveform by sequentially switching between different voltage levels using the high-side and low-side transistors comprised of MOSFETs.

4. The apparatus of claim 1, wherein the control circuit is configured to generate an asymmetric biphasic waveform by alternating the high-side and low-side transistors comprised as MOSFETs to create a waveform with differing positive and negative amplitudes.

5. The apparatus of claim 1, wherein the half-bridge drivers are configured to output a pulsed waveform, wherein the control circuit applies high-impedance periods between pulses to allow for tissue recovery between stimulation bursts.

6. The apparatus of claim 1, further comprising an adjustable control interface configured to allow a user to modify the amplitude, frequency, and durationof the output waveform to customize the electrical stimulation delivered to the ocular tissue.

7. The apparatus of claim 1, wherein the output terminals are connected to a pair of electrodes configured to be positioned on the eye, and the control circuit generates a square wave alternating between the first voltage and the second voltage to produce a biphasic treatment waveform.

8. A method for delivering microcurrent stimulation to ocular tissue, comprising: providing a power supply configured to output a first voltage and a second voltage; controlling a three half-bridge driver circuit, wherein each half-bridge driver includes a high-side transistor and a low-side transistor; selectively switching the high-side and low-side transistors to generate an electrical waveform; applying the electrical waveform to electrodes in contact with ocular tissue; and delivering microcurrent stimulation based on the waveform generated by the half-bridge driver circuit.

9. The method of claim 8, further comprising the steps of: generating a stepped treatment waveform by incrementally increasing the voltage output by the high-side transistor and decreasing the voltage output by the low- side transistor in predetermined intervals; and applying the stepped waveform to the ocular electrodes to deliver controlled stimulation.

10. The method of claim 8, further comprising the steps of: generating an asymmetric biphasic waveform by alternately activating the high- side transistor and low-side transistor to create positive and negative phases of differing amplitudes; anddelivering the asymmetric biphasic waveform to the electrodes to stimulate the ocular tissue with alternating current.

11. The method of claim 8, further comprising: generating a pulsed waveform by switching the high-side transistor on for a first pulse and the low-side transistor on for a second pulse, interspersed with high- impedance periods where neither transistor is activated; and applying the pulsed waveform with high-impedance periods to allow recovery time for the ocular tissue between stimulation bursts.

12. The method of claim 8, wherein the control of the high-side and low- side transistors is based on real-time feedback from impedance sensors monitoring the contact between the electrodes and the ocular tissue, the method further comprising adjusting the waveform characteristics in response to changes in electrode impedance to optimize stimulation delivery.

13. The method of claim 8, further comprising generating a triangular waveform by gradually increasing the voltage applied by the high-side transistor, followed by a high-impedance period, and then gradually decreasing the voltage by activating the low-side transistor, to create a smooth ramp-up and ramp-down waveform applied to the ocular electrodes.

14. The method of claim 8, further comprising using a control interface to adjust the amplitude, frequency, and duration of the waveform applied by the three halfbridge driver circuit, allowing for customizable microcurrent stimulation based on the patient’s therapeutic needs.

15. A non-transitory computer-readable storage medium storing a program for causing a computer to execute a control method for generating an ocular microcurrent treatment signal, the method comprising: controlling a three half-bridge driver circuit, wherein each half-bridge driver includes a high-side MOSFET and a low-side MOSFET;selectively switching the high-side and low-side MOSFETs to generate an electrical signal; and applying the electrical signal to electrodes in contact with ocular tissue to deliver microcurrent stimulation.

16. The non-transitory computer-readable storage medium of claim 15, wherein the method further comprises: generating a stepped waveform by incrementally increasing the output of the high-side MOSFET and decreasing the output of the low-side MOSFET; and applying the stepped waveform to electrodes positioned in contact with ocular tissue.

17. The non-transitory computer-readable storage medium of claim 15, wherein the method further comprises: generating an asymmetric biphasic waveform by alternating activation of the high-side and low-side MOSFETs to create a waveform with different positive and negative amplitudes; and applying the asymmetric biphasic waveform to electrodes in contact with ocular tissue.

18. The non-transitory computer-readable storage medium of claim 15, wherein the method further comprises: generating a pulsed waveform by switching the high-side MOSFET on for a first pulse, switching the low-side MOSFET on for a second pulse, and introducing high-impedance periods between pulses; and applying the pulsed waveform to the electrodes to provide intermittent microcurrent stimulation.

19. The non-transitory computer-readable storage medium of claim 15, wherein the method further comprises:generating a triangular waveform by gradually increasing the voltage applied by the high-side MOSFET, introducing a high-impedance period, and gradually decreasing the voltage applied by the low-side MOSFET; and applying the triangular waveform to electrodes in contact with ocular tissue.

20. The non-transitory computer-readable storage medium of claim 15, wherein the method further comprises: adjusting the amplitude, frequency, and duration of the waveform applied by the three half-bridge driver circuit using a control interface; and generating a customized waveform for application to electrodes in contact with ocular tissue based on the patient's therapeutic needs.

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