Ultrasound stimulation for non-invasive visual prostheses

Abstract

Globally, it is estimated there are more than 2.2 billion visually impaired people. Visual diseases such as retinitis pigmentosa, age-related macular degeneration, glaucoma, and optic neuritis can cause irreversible profound vision loss. Many groups have investigated different approaches such as microelectronic prostheses, optogenetics, stem cell therapy, and gene therapy to restore vision. However, these methods have some limitations such as invasive implantation surgery and unknown long-term risk of genetic manipulation. In addition to the safety of ultrasound as a medical imaging modality, ultrasound stimulation can be a viable non-invasive alternative approach for the sight restoration because of its ability to non-invasively control neuronal activities. Indeed, recent studies have demonstrated ultrasound stimulation can successfully modulate retinal/brain neuronal activities without causing any damage to the nerve cells. Superior penetration depth and high spatial resolution of focused ultrasound can open a new avenue in neuromodulation researches. This review summarizes the latest research results about neural responses to ultrasound stimulation. Also, this work provides an overview of technical viewpoints in the future design of a miniaturized ultrasound transducer for a non-invasive acoustic visual prosthesis for non-surgical and painless restoration of vision.

Nanoparticle-based optical interfaces for retinal neuromodulation: a review

“…The capacity of low intensity focused ultrasound to provide non-invasive and reversible modulation of neural activity with spatial selectivity on the-millimeter scale has been known since 1929 ( Harvey, 1929 ). The technique has recently attracted significant attention for transcranial modulation of the central nervous system, particularly since it was recognized that nerve activity could be excited or suppressed, depending on the combination of ultrasound parameters, experimental models and conditions ( Naor et al, 2016 ; Fomenko et al, 2018 ; Blackmore et al, 2019 ; Rabut et al, 2020 ; Wang et al, 2020 ; Zhang T. T. et al, 2021 ; Badadhe et al, 2022 ). High intensity focused ultrasound is understood to ablate tissue due to heat generated by the mechanical wave interacting with the tissue, whereas low intensity ultrasound has demonstrated a favorable safety profile ( Pasquinelli et al, 2019 ; Radjenovic et al, 2022 ).…”

“…This confluence has encouraged pilot studies of ultrasonic stimulation of the retina as an alternative approach to vision restoration in cases of retinal degeneration. This topic has been comprehensively reviewed, together with the associated engineering challenges for developing an acoustic retinal prosthesis ( Naor et al, 2016 ; Lo et al, 2020 ; Rabut et al, 2020 ; Badadhe et al, 2022 ; Lu et al, 2022 ). In an initial report, Naor et al (2012) were able to record potentials from the scalps of anesthetized rats evoked by ultrasound directed towards their retina.…”