Credit: Anne Brooke USFWS

US researchers have stimulated blind rat retinas with ultrasound, enabling them to perceive basic shapes, a technique they said could allow a non-invasive therapy for some forms of blindness.

The research team, led by Professor Qifa Zhou from the University of Southern California, created a small ultrasound device that directs sound waves to the retina. “The neurons present in the retina possess channels that respond to mechanical stimulation,” explained Gengxi Lu, a PhD student in Prof Zhou’s lab. “These neurons are activated when we use ultrasound to generate mechanical pressure,” he said.

Having applied the system to blind rats, the team measured activity in the visual cortex via a multi-electrode array. They found the rat was able to perceive visualisations comparable to the pattern of ultrasound stimulation projected to the eye. Although researchers used a transducer in front of the rat’s eyeball to send the ultrasound signals, their ultimate goal is to create a wireless contact lens, said Prof Zhou.