Researchers are making further advances in creating an artificial retina to restore vision for some people with severely limited vision. In this case, scientists at Okayama University have conducted animal trials to demonstrate the effectiveness of a new technology.
The technology relies on thin polyethylene plastic film. Rather than create a matrix of photosensors and electrodes, the system uses a photoelectric dye that converts light energy into electricity. This thin film was implanted between the retina layer and the back of the eye in rats that are specially bred to develop retinitis pigmentosa (which causes the light-sensing retina cells to die). The electricity generated by the light hitting the film directly stimulates the optic nerves. In an experiment demonstrating this implant technology, seven rats received implants with the dye-sensitized film, while another seven in a control group received implants of the untreated plastic film.
By measuring brain activity, the researchers were able to detect significantly greater response to a flashing light stimulus in the experimental group compared with the control group, eight weeks after implantation. Previous studies have shown behavioral changes in rats with the implants, indicating that their vision has been restored. The team is now planning for human clinical trials in Japan in the near future. This new approach appears to hold great promise for restoring vision in people who have lost it.