Optic Nerve Stimulation to Aid the Blind
August 21, 2019 | EPFLEstimated reading time: 2 minutes

Scientists from EPFL in Switzerland and Scuola Superiore Sant’Anna in Italy are developing technology for the blind that bypasses the eyeball entirely and sends messages to the brain. They do this by stimulating the optic nerve with a new type of intraneural electrode called OpticSELINE. Successfully tested in rabbits, they report their results in Nature Biomedical Engineering.
“We believe that intraneural stimulation can be a valuable solution for several neuroprosthetic devices for sensory and motor function restoration. The translational potentials of this approach are indeed extremely promising,” explains Silvestro Micera, EPFL’s Bertarelli Foundation Chair in Translational Neuroengineering, and Professor of Bioelectronics at Scuola Superiore Sant’Anna, who continues to innovate in hand prosthetics for amputees using intraneural electrodes.
Blindness affects an estimated 39 million people in the world. Many factors can induce blindness, like genetics, retinal detachment, trauma, stroke in the visual cortex, glaucoma, cataract, inflammation or infection. Some blindness is temporary and can be treated medically. How do you help someone who is permanently blind?
The idea is to produce phosphenes, the sensation of seeing light in the form of white patterns, without seeing light directly. Retinal implants, a prosthetic device for helping the blind, suffer from exclusion criteria. For example, half a million people worldwide are blind due to retinitis pigmentosa, a genetic disorder, but only a few hundred patients qualify for retinal implants for clinical reasons. A brain implant that stimulates the visual cortex directly is another strategy albeit risky. A priori, the new intraneural solution minimizes exclusion criteria since the optic nerve and the pathway to the brain are often intact.
Previous attempts to stimulate the optic nerve in the 1990s provided inconclusive results. EPFL’s Medtronic Chair in Neuroengineering Diego Ghezzi explains, “Back then, they used cuff nerve electrodes. The problem is that these electrodes are rigid and they move around, so the electrical stimulation of the nerve fibers is unstable. The patients had a difficult time interpreting the stimulation, because they kept on seeing something different. Moreover, the cuff electrodes probably had limited selectivity because they recruited superficial fibers.”
Intraneural electrodes may indeed be the answer for providing rich visual information to the subjects. They are also stable and less likely to move around once implanted in a subject, according to the scientists. Cuff electrodes are surgically placed around the nerve, whereas intraneural electrodes pierce through the nerve.
Together, Ghezzi, Micera and their teams engineered the OpticSELINE, an electrode array of 12 electrodes. In order to understand how effective these electrodes are at stimulating the various nerve fibers within the optic nerve, the scientists delivered electric current to the optic nerve via OpticSELINE and measured the brain’s activity in the visual cortex. They developed an elaborate algorithm to decode the cortical signals. They showed that each stimulating electrode induces a specific and unique pattern of cortical activation, suggesting that intraneural stimulation of the optic nerve is selective and informative.
As a preliminary study, the visual perception behind these cortical patterns remains unknown. Ghezzi continues, “For now, we know that intraneural stimulation has the potential to provide informative visual patterns. It will take feedback from patients in future clinical trials in order to fine-tune those patterns. From a purely technological perspective, we could do clinical trials tomorrow.”
With current electrode technology, a human OpticSELINE could consist of up to 48-60 electrodes. This limited number of electrodes is not sufficient to restore sight entirely. But these limited visual signals could be engineered to provide a visual aid for daily living.
Testimonial
"The I-Connect007 team is outstanding—kind, responsive, and a true marketing partner. Their design team created fresh, eye-catching ads, and their editorial support polished our content to let our brand shine. Thank you all! "
Sweeney Ng - CEE PCBSuggested Items
Weaning the U.S. Military Off a Tablet Supply Chain That Leads to China
09/08/2025 | Jim Will, USPAETablet computers are essential to how our military fights, moves and sustains, but these devices are built on a fragile global supply chain with strong ties to China. Building domestic manufacturing to eliminate this vulnerability is feasible if we tap into the information and capabilities that already exist and create strong demand for tablets produced by trusted and assured sources.
Standard of Excellence: The Human Touch in an Automated World
08/27/2025 | Anaya Vardya -- Column: Standard of ExcellenceWe live in a world where everything from groceries to tech support is a click away. Automation has revolutionized the way we conduct business. From order tracking systems to AI-powered chatbots, automation can increase speed, improve accuracy, and reduce costs. However, with all that progress comes a critical challenge: How do we ensure that we don’t lose the human touch, the very thing that makes business relationships meaningful?
Marcy’s Musings: Continuing to Invent the Future With SEL
08/19/2025 | Marcy LaRont -- Column: Marcy's MusingsTwo years ago, PCB007 Magazine devoted an issue to Schweitzer Engineering Labs (SEL), a new captive greenfield PCB facility in Moscow, Idaho. We highlighted some of the most cutting-edge achievements in facility layout, design, and equipment in the PCB fabrication industry. SEL was a shining example of what was possible, providing insight and inspiration to PCB fabricators looking toward growth and expansion.
Global Excellence in PCB Design: The Global Electronics Association Expands to Italy
08/07/2025 | Global Electronics AssociationIn today's rapidly evolving electronics industry, printed circuit boards (PCBs) serve as the critical backbone influencing the success, reliability, and time-to-market of countless products. Recognizing this essential role, the Global Electronics Association (formerly IPC), a worldwide leader in electronics standards, certification, and education, is now expanding its internationally acclaimed PCB design training to Italy.
Driving Innovation: Inner Layer Alignment Methods in PCB Production
08/06/2025 | Kurt Palmer -- Column: Driving InnovationIn PCB manufacturing, precision is a fundamental requirement. Among many complex processes, the accurate registration of inner layers before lamination is one of the most critical. Much like a child's game where rings must be perfectly stacked onto a single pin, PCB manufacturers align multiple conductive and insulating layers to form a cohesive, functional board. This alignment directly affects PCB precision; tighter layer alignment results in smaller "annular rings," superior performance, and higher yields.