Noninvasive Ultrasound Retinal Stimulation for Vision Restoration at High Spatiotemporal Resolution

Xuejun Qian; Gengxi Lu; Biju B Thomas; Runze Li; Xiaoyang Chen; K Kirk Shung; Mark Humayun; Qifa Zhou

doi:10.34133/2022/9829316

Noninvasive Ultrasound Retinal Stimulation for Vision Restoration at High Spatiotemporal Resolution

BME Front. 2022 Feb 21:2022:9829316. doi: 10.34133/2022/9829316. eCollection 2022.

Authors

Xuejun Qian^#^{1

2}, Gengxi Lu^#^{1

2}, Biju B Thomas², Runze Li^{1

2}, Xiaoyang Chen¹, K Kirk Shung¹, Mark Humayun^{1

2

3}, Qifa Zhou^{1

2}

Affiliations

¹ Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA.
² Department of Ophthalmology, University of Southern California, Los Angeles, CA 90033, USA.
³ USC Ginsburg Institute for Biomedical Therapeutics, University of Southern California, Los Angeles, CA 90033, USA.

^# Contributed equally.

Abstract

Objective. Retinal degeneration involving progressive deterioration and loss of function of photoreceptors is a major cause of permanent vision loss worldwide. Strategies to treat these incurable conditions incorporate retinal prostheses via electrically stimulating surviving retinal neurons with implanted devices in the eye, optogenetic therapy, and sonogenetic therapy. Existing challenges of these strategies include invasive manner, complex implantation surgeries, and risky gene therapy. Methods and Results. Here, we show that direct ultrasound stimulation on the retina can evoke neuron activities from the visual centers including the superior colliculus and the primary visual cortex (V1), in either normal-sighted or retinal degenerated blind rats in vivo. The neuron activities induced by the customized spherically focused 3.1 MHz ultrasound transducer have shown both good spatial resolution of 250 μm and temporal resolution of 5 Hz in the rat visual centers. An additional customized 4.4 MHz helical transducer was further implemented to generate a static stimulation pattern of letter forms. Conclusion. Our findings demonstrate that ultrasound stimulation of the retina in vivo is a safe and effective approach with high spatiotemporal resolution, indicating a promising future of ultrasound stimulation as a novel and noninvasive visual prosthesis for translational applications in blind patients.