A bionic eye under development has shown to be safe and stable for long-term implantation in a three-month animal study, paving the way towards human trials.
The Phoenix99 Bionic Eye, being developed by University of Sydney and UNSW, 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 consists of two main implants: a stimulator attached to the eye and a communication module positioned under the skin behind the ear.
Published in Biomaterials, 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 is now confident the device could be trialled in human patients and have applied for ethical approval.
The Phoenix99 Bionic Eye works by stimulating the retina which, in healthy eyes, the cells in one of the layers turn incoming light into electrical messages. 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. There were no unexpected reactions from the tissue around the device and we expect it could safely remain in place for many years,” said Mr Samuel Eggenberger, a biomedical engineer who is completing his doctorate with Head of School of Biomedical Engineering Professor Gregg Suaning.
“Our team is thrilled by this extraordinary result, which gives us confidence to push on towards human trials of the device. We hope that through this technology, people living with profound vision loss from degenerative retinal disorders may be able to regain a useful sense of vision,” said Mr Eggenberger.
Professor Gregg Suaning said the positive results are a significant milestone for the Phoenix99 Bionic Eye.
“This breakthrough comes from combining decades of experience and technological breakthroughs in the field of implantable electronics,” said Prof Suaning.
A patient is implanted with the Phoenix99, and a stimulator is positioned on the eye and a communication module implanted behind the ear. A tiny camera attached to glasses captures the visual scene in front of the wearer, and the images are processed into a set of stimulation instructions which are sent wirelessly through to the communication module of the prosthesis.
The implant then transfers the instructions to the stimulation module, which delivers electrical impulses to the neurons of the retina. The electrical impulses, delivered in patterns matching the images recorded by the camera, trigger neurons which forward the messages to the brain, which interprets the signals as seeing the scene.
Source: University of Sydney
