In Vivo Safety Evaluation of Acoustic Radiation Force for Optical Coherence Elastography of the Crystalline Lens.

Purpose: To evaluate the safety of acoustic radiation force (ARF) for in vivo lens biomechanics measurement in rabbits. Methods: Twelve New Zealand albino white rabbits were exposed to acoustic radiation force at intensities exceeding the US Food and Drug Administration (FDA)-recommended safety limits by 8 to 14 times. A spherically focused 3.5-MHz ARF transducer created deformations on the lens surface, which was imaged using a spectral-domain optical coherence tomography system during the ARF application. Intraocular pressure measurements and ocular health assessments using slit-lamp and OCT imaging were conducted pre- and postexposure over 3 weeks. Results: Hyperemia was observed in two rabbits immediately postexposure but resolved within 24 hours. No substantial changes in intraocular pressure were detected, and both slit-lamp examination and optical coherence tomography imaging showed normal ocular health across all groups after the follow-up period. Conclusions: ARF is a potentially safe technique for assessing the biomechanical properties of the lens in vivo. No eye damage was observed, even when ARF was applied at intensities well above FDA regulatory limits. Translational Relevance: This study is an important step toward the translation of the technology for ARF elastography of the crystalline lens, for studies on the mechanism of presbyopia, and to enable the assessment of new presbyopia treatments relying on lens softening.