Retinal implants may help the blind see

A group of French researchers is hoping its work will make what once seemed like science fiction a reality: Making blind people see again.

Diego Ghezzi, the Medtronic Chair in Neuroengineering at the École Polytechnique Fédérale de Lausanne (EPFL), has made this the focus of his research. Since 2015, he and his team have been developing a retinal implant that works with camera-equipped smart glasses and a microcomputer.

“Our system is designed to give blind people a form of artificial vision by using electrodes to stimulate their retinal cells,” Ghezzi said in a EPFL release.

The system includes a camera embedded in the smart glasses captures images in the wearer’s field of vision, and sends the data to a microcomputer placed in one of the eyeglasses’ end-pieces.

The data is sent to a microcomputer, which turns the data into light signals which are transmitted to electrodes in the retinal implant. The electrodes then stimulate the retina in such a way that the wearer sees a simplified, black-and-white version of the image.

According to EPFL, this simplified version is made up of dots of light that appear when the retinal cells are stimulated. The wearers must learn to interpret the many dots of light in order to make out shapes and objects.

“It’s like when you look at stars in the night sky – you can learn to recognize specific constellations,” Ghezzi explained in the release. “Blind patients would see something similar with our system.”

According to EPFL, the system has yet to be tested on humans, and the research team still hopes to be certain of its results.

Ghezzi noted in the release that securing the medical approvals necessary takes time.

“We came up with a process for testing it virtually – a type of work-around,” he explained.

According to EPFL, the retinal implants they developed contain 10,500 electrodes, with each one serving to generate a dot of light.

Ghezzi noted that the researchers were not sure if the number of electrodes would be too many or too few. 

“We had to find just the right number so that the reproduced image doesn’t become too hard to make out,” he said in the statement. “The dots have to be far enough apart that patients can distinguish two of them close to each other, but there has to be enough of them to provide sufficient image resolution.”

Moreover, Ghezzi pointed out in the release that the engineers had to ensure that each electrode could reliably produce a dot of light.

“We wanted to make sure that two electrodes do not stimulate the same part of the retina,” he said. “So we carried out electrophysiological tests that involved recording the activity of retinal ganglion cells. And the results confirmed that each electrode does indeed activate a different part of the retina.”

Ghezzi explained that the team’s experiments indicated that the system’s capacity does not need to be improved any further, and is ready for clinical trials.