Electrical stimulation for the treatment of blindness?
Newly developed technology can help blind people see it again. Supplying the optic nerve with electrical current through a special electrode stimulates the visual cortex.
A recent study by the École polytechnique fédérale de Lausanne and Scuola Superiore Sant & # 39; Anna found that the electrode can supply the optic nerves of rabbits, leading to stimulation of the visual cortex. The results of the study were published in the English journal Nature Biomedical Engineering.
Retinal implants are only suitable for a few people
Millions of people around the world cannot or only partially see them. Although this is often due to retinal damage, few people are suitable for retinal implantation. The retina is located in the back of the eye and captures photographs, which transform the optic nerve into impulses. They are sent to the brain, where the image is created.
Electrical stimulation of the optic nerve in rabbits
In the study, the rabbit optic nerve was directly supplied with electricity through an OpticSELINE electrode. This stimulated the visual cortex of animals, a brain region where information from the retina is processed. It is unclear whether this will allow the blind person normal vision, but the potential of the technology is becoming clear, the researchers said.
How Do Retinal Implants Work?
Retinal implants have been developed for the genetic disorder of retinitis pigmentosa. The method involves replacing damaged retinal cells with electronic implants that stimulate the remaining healthy cells to generate a signal along the optic nerve. The implant requires a small incision in the eye. Retinal implants can help restore the sight of people who are blind on the retina due to cell loss. The retinal implant contains electrodes that stimulate the cells of the retina. It is basically a network of implants that are placed directly on the retina. The implants are then connected to the glasses, the computer and the portable microcomputer. The camera captures images that enter the user's field of view and sends them to a computer. The computer converts this image into electrical signals that are transmitted to the electrodes. The electrodes stimulate the cells in the retina based on the patterns of light detected in the field of view. The patient must then learn to interpret the incoming visual sensations to be able to see. Because the method has only limited success so far, users are still dependent on visual aids like guide dogs.
Optical Implant Problems
Researchers are working to create a grid with a larger surface area to expand the user's field of view and improve the quality of the displayed image. Customizing the implant is also a challenge. The incision in the eyes should be as small as possible to avoid tissue damage. Since the 1990s, attempts have been made to restore vision by stimulating the optic nerve. At the time, so-called cuff nerve electrodes were used. The problem is that these electrodes are rigid and moving, making electrical stimulation of nerve fibers unstable, the researchers said. Patients had difficulty interpreting stimulation because they still saw something different.
Intraneural stimulation can create informative visions
In the current method, the research group used intraneural electrodes. OpticSELINE was created from twelve electrodes, which together gave electrical power to the rabbit's visual cortex. The researchers monitored activity in this part of the brain and developed a sophisticated signal decoding algorithm. They found that each electrode resulted in a specific and unique pattern of cortical activation. The study is now clear that intraneural stimulation can create informative visions, the researchers explain. (As)
- Vivien Gaillet, Annarita Cutrone, Fiorenzo Artoni, Paola Vagni, Ariastity Mega Pratiwi et al .: Spatial selective activation of the visual cortex by intraneural stimulation of the optic nerve, in Nature Biomedical Engineering (Inquiry: 08/20/2019), Nature Biomedical Engineering