A bionic eye being developed by a team of researchers at the University of Sydney and the University of New South Wales has shown to be safe and stable for long-term implantation in a three-month study, paving the way toward human trials. The Phoenix99 Bionic Eye is an implantable system, designed to restore a form of vision to patients living with severe vision impairment and blindness caused by degenerative diseases such as retinitis pigmentosa. The device has two main components that need to be implanted: a stimulator attached to the eye and a communication module positioned under the skin behind the ear. The researchers used a sheep model to observe how the body responds and heals when implanted with the device, with the results allowing for further refinement of the surgical procedure. The biomedical research team says the device could be trialed in human patients. The Phoenix99 works by stimulating the retina – a thin stack of neurons lining the back of the eye. In healthy eyes, the cells in one of the layers turn incoming light into electrical messages that are sent to the brain. In some retinal diseases, the cells responsible for this crucial conversion degenerate, causing vision impairment. The system bypasses these malfunctioning cells by stimulating the remaining cells directly, effectively tricking the brain into believing that light was sensed. “Importantly, we found the device has a very low impact on the neurons required to ‘trick’ the brain,” said Samuel Eggenberger, a biomedical engineer who is completing his doctorate with Head of School of Biomedical Engineering professor Gregg Suaning. “There were no unexpected reactions from the tissue around the device, and we expect it could safely remain in place for many years.” The team will now apply for ethics approval to perform clinical trials in human patients, as they continue to develop and test advanced stimulation techniques.