Axial current steering modulates lens pathology-dependent intraocular electric convergence under temporally interfering electrical stimulation: a computational analysis

Temporal Interference Stimulation (TIS) is a low invasive technique for retinal modulation that utilizes the interference of high-frequency electric fields. Compared to conventional transcorneal electrical stimulation, TIS, by virtue of its enhanced depth penetration capabilities, enables selective modulation of deep-seated central retina, thereby establishing itself as a promising precise-therapeutic modality for diverse retinal pathologies. Clinically, retinal pathologies frequently coexist with concurrent lens pathologies. However, the functional efficacy of TIS in ocular systems with lens pathologies remains undocumented in current scientific literature. To explore intraocular electrical convergence under TIS, this study constructed multi-layered finite element models of normal aged and lens diseased human eyeball (NAE and LDE) with detailed anterior segment structures. The results firstly demonstrated a stable ground setting with compromising computational efficiency in NAE model. Subsequently, we found that lens lesions elevate the Lens Potential Convergence (LPC) up to 36.05% ± 0.06% (SD) of retinal potential levels in LDE model (compared with 28.10% ± 0.09% (SD) in NAE model as a reference). Using Axial Current Steering (ACS) by adjusting the current ratio between electrodes within paired channels, LPC was successfully reduced to 3.62% ± 0.01% (SD), accompanied by a 28% reduction in 90% retinal potential peak width surprisingly. This work elucidates the interference mechanisms of TIS targeting in enriched eye model and validates the effectiveness of the proposed ACS strategy, providing theoretical support for the future clinical application of TIS.