Suprachoroidal Retinal Stimulation Leveraging Temporal Interference Technology: A Modelling Study.

A suprachoroidal retinal prosthesis is implanted between the choroid and the sclera, offering the advantages of low surgical complexity and high stability. However, the relatively longer distance between electrodes and the retina leads to higher retinal ganglion cells (RGC) excitation threshold and lower spatial resolution. To maximize the advantages of suprachoroidal stimulation (SS), it is of great significance to explore additional strategies to lower the threshold and improve the spatial resolution. Temporal interference (TI) was reported to induce localized neural excitation in deep regions, indicating a promising avenue for enhancing suprachoroidal retinal stimulation. This study combines the advancements of TI and SS, resulting in the novel approach of Temporal Interference-Suprachoroidal Stimulation (TI-SS). The effect of electrode position and size on the distribution of the maximum electric potential (EP max ) generated by TI-SS was investigated by finite element modelling. Higher EP max values corresponds to lower RGC excitation threshold. In addition, the EP max distribution induced by TI-SS and SS were compared. Our simulation suggests a decrease in EP max value when stimulating electrodes are moved from cornea to sclera under TI-SS. And the EP max distribution exhibits a notable transition from a bimodal distribution to a unimodal distribution as the return electrodes are moved to the posterior of the eyeball and get closer. The EP max values induced by TI-SS is generally higher than those induced by SS, indicating that RGC excitation threshold triggered by TI-SS is lower compared to SS. This study offers preliminary evidence demonstrating the enhanced performance of TI-SS in comparison to conventional SS approach.