Researchers have developed a new type of retinal implant that significantly restores lost vision field. This innovation by Ecole Polytechnique Fédérale de Lausanne (EPFL) engineers can help people who have become blind due to the loss of photoreceptor cells in their retinas.
The retinal implant 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," says Diego Ghezzi, who holds the Medtronic Chair in Neuroengineering (LNE) at EPFL's School of Engineering.
The 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 microcomputer 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. This simplified version is made up of dots of light that appear when the retinal cells are stimulated. However, 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. Blind patients would see something similar with our system," says Ghezzi.
However, the system has not yet been tested on humans. The research team first needs to be certain of their results. "We aren't yet authorized to implant our device in human patients, since obtaining the medical approval takes a long time. But we came up with a process for testing it virtually—a type of work-around," says Ghezzi. More specifically, the engineers developed a virtual reality program that can simulate what patients would see with the implants. Their findings have just been published in Communication Materials.
The engineers have performed tests at constant resolution but different field-of-vision angles. "We started at five degrees and opened up the field all the way to 45 degrees. We found that the saturation point is 35 degrees—the object remains stable beyond that point," says Ghezzi. All these experiments demonstrated that the system's capacity doesn't need to be improved any further, and that it's ready for clinical trials. But the team will have to wait a little longer before their technology can be implanted in actual patients.
