A flexible high-precision photoacoustic retinal prosthesis

Abstract

Retinal degenerative diseases of photoreceptors are a leading cause of blindness with no effective treatment. Retinal prostheses aim to restore sight by stimulating remaining retinal cells. Here, we present a photoacoustic retinal stimulation technology. We designed a polydimethylsiloxane and carbon-based flexible film that converts near-infrared laser pulses into a localized acoustic field with 56-μm lateral resolution, aiming at high-precision acoustic stimulation of mechanosensitive retinal cells. This photoacoustic stimulation resulted in robust and localized modulation of retinal ganglion cell activity in both wild-type and degenerated ex vivo retinae. When a millimeter-sized photoacoustic film was implanted in the rat subretinal space, pulsed laser stimulation generated neural modulation in vivo along the visual pathway to the superior colliculus, as measured by functional ultrasound imaging. The biosafety of the film was confirmed by the absence of short-term adverse effects under optical coherence tomography retinal imaging, while local thermal increases were measured below 1 °C. These findings demonstrate the potential of photoacoustic stimulation for high-acuity visual restoration over a large field of view in blind patients.