## 4 Discussion  
This study presents a novel wireless digital controller for high-density stimulation devices. The proposed system addresses key challenges in retinal prostheses, including resolution enhancement, crosstalk reduction, and flicker-free vision. By integrating a hexagonal electrode structure and an overlapping stimulation technique, the system effectively mitigates the drawbacks of high-density electrode arrays while maintaining low power consumption.  
One of the key challenges in high-density retinal implants is electrical crosstalk, which can reduce spatial resolution and lead to distorted visual perception [20]. Our system addresses this issue by placing the reference electrode near the active electrodes, thereby limiting the spread of charge and preventing unwanted activation. This spatial optimization is essential in high-resolution retinal prostheses, as previous studies have shown that higher electrode densities improve visual acuity and increase crosstalk risks [25]. By incorporating a hexagonal stimulation pattern, our digital controller effectively controls the stimulation area.  
Power efficiency is critical in retinal implants, as excessive power consumption can lead to heat dissipation and potential tissue damage [17]. Our system consumes 3.2 mW, slightly higher than some previous designs but necessary to support the 256 independent stimulation channels. The overlapping stimulation technique balances this trade-off, which ensures a flicker-free vision frequency, enhancing patient comfort [26]. Future work should focus on optimizing power management strategies to reduce energy consumption further while maintaining high-resolution stimulation.  
Another key contribution of our study is the global digital controller, which enables dynamic pulse shaping with 128 distinct biphasic pulse patterns, allowing patient-specific stimulation adjustments. Tailoring stimulation parameters is essential for minimizing current leakage and preventing overstimulation [7,8]. While our system demonstrated stable performance, further improvements in stimulation algorithms could enhance spatial resolution and long-term efficacy, ensuring its clinical viability.  
Despite these advancements, this study has limitations that should be addressed in future research. While the system was validated through simulations and prototype testing, further biological validation using animal models or clinical trials is necessary to assess its safety and efficacy in real physiological environments. Additionally, although the hexagonal stimulation pattern effectively reduces crosstalk, further refinement of stimulation algorithms could enhance spatial resolution. Future research should explore  
Figure 10: (**a**) Measurement environment picture for this work. (**b**) Oscilloscope results were captured for received data and current pulses generated with respect to data.  
higher-density electrode arrays, machine learning-based adaptive stimulation, and long-term clinical trials to ensure the system's real-world viability. By integrating optimized pulse shaping, efficient wireless telemetry, and a compact digital architecture, our system represents a clinically promising advancement in high-density retinal prostheses, offering a potential breakthrough for patients with retinal degenerative diseases.