Scientists at Ecole Polytechnique Federale de Lausanne in Switzerland have developed a new technology that can completely bypass the eyeball and send messages directly to the brain through the optic nerve. The new type of intraneural electrode is expected to provide a visual aid for permanently blind people. The intraneural electrode is called OpticSELINE.
Retinal implants to treat blindness are taking a faster pace in development. The concept of this technology involves allowing users to sense light, which is experienced as a white pattern. The technology doesn’t provide full vision, but it can provide a visual aid to blind people for doing simple daily life tasks. Retinal implants can help people who have visual impairments, but it is not suitable for completely blind people.
Implanting a device in the brain that can directly stimulate the visual cortex is another option for visual aid. This options is risky because and is hardly used for general therapy. As many people still have their optic nerve connection with the brain intact, scientists have developed a device that stimulates the optic nerve.
“We believe that intraneural stimulation can be a valuable solution for several neuroprosthetic devices for sensory and motor function restoration,” said Silvestro Micera, a researcher involved in the study. “The translational potential of this approach is extremely promising.”
Researchers have previously attempted to develop such techniques, as early as the 1990s. “Back then, they used cuff nerve electrodes,” explained Diego Ghezzi, another researcher involved in the study. “The problem is that these electrodes are rigid and they move around, so the electrical stimulation of the nerve fibers becomes unstable. The patients had a difficult time interpreting the stimulation because they kept on seeing something different. Moreover, they probably have limited selectivity because they recruited superficial fibers.”
The latest device developed by the scientists contains electrodes that directly penetrate into the optic nerve. These intraneural electrodes are more stable than cuff electrodes. To test the functioning of this device, the researchers delivered an electric current in rabbits and monitored their brain activity. Each electrode generated a different response in the brain, indicating that the device can produce stimulation.
“For now, we know that intraneural stimulation has the potential to provide informative visual patterns,” said Ghezzi. “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.”