Impact of Ultrasound Transducer Positioning on Acoustic Particle Manipulation in the Anterior Chamber

Purpose: A novel noninvasive technique utilizing standing acoustic waves has been developed to trap and redirect intraocular particles within the anterior chamber, presenting a potential preventive treatment for pathologies such as hyphema and pigmentary glaucoma. Because clinical translation requires a rigorous understanding of the influence of geometric parameters, the purpose of this study is to investigate the effects of transducer positioning, incidence angle, and impact contour to define the operational window for successful acoustic manipulation. Methods: We conducted experimental and numerical investigations to evaluate how acoustic trapping at nodal regions can be used to guide particles away from the trabecular meshwork. To thoroughly assess the particle manipulation, the experimental results were quantitatively analyzed and validated against a two-dimensional Finite Element Acoustic Model (FEAM) alongside theoretical Gor’kov radiation force calculations to predict nodal formation and trap stability. Results: Our findings indicate that low incidence angles (5°–15°) are critical for maximizing the effective standing wave potential and ensuring efficient particle control. Conversely, incidence angles exceeding 30° result in a transition from stable standing waves to acoustic streaming dominance, which serves as the primary failure mode. Furthermore, while a 4 mm impact contour at 15° improves trapping consistency along the x-axis compared to a 2 mm contour, broader z-axis streaks imply trade-offs regarding effective particle sweeping. The FEAM and Gor’kov force calculations demonstrated high compatibility in predicting the experimental nodal formations. Conclusions: This study quantitatively establishes the geometric baselines and operational windows required to optimize intraocular acoustic manipulation. By identifying the optimal transducer parameters and acoustic streaming failure modes, these findings provide a crucial foundation for the future clinical translation of this noninvasive technique.