gms | German Medical Science

Optogenetics is a gene therapy technique which holds lots of potential as a neural interface but also has lots of challenges. It is currently under trial both in the US and Europe for use in a retinal prosthesis form of visual restoration for those with Retinitis Pigmentosa. These trials have been underway for 4 years at the time writing but are as yet unpublished. Perhaps the most important conclusion to date is that optogenetics has done no harm. This can, therefore, indicate safe use in deeper brain regions to treat other conditions. We have a major fund called CANDO to bring an optogenetic clinical solution for use in the brain. The first target is actually epilepsy, as resection of the seizure focus is an existing clinical solution. But in parallel, we are exploring optogenetic methods for use in a visual cortical prosthesis. We have therefore developed an exemplar clinically translatable system, as well as version for experiments in non-human primates. Clinical exemplar system: We have developed a headset operating under battery power, which incorporates an imaging system and video processor. The headset also transmits both wireless power and data to the implant control system. This control system sits inside a hermetic case and transmits power and data to a brain unit which stimulates the visual cortex. Our project has a clinical translation focus, so much of our effort has been to develop innovations to ensure implant longevity and stability. In addition, key issues such as thermal impact and photochemical damage have been explored with respect to the regulatory frameworks. Non-human primate test system: We have been doing limited studies of single LED probes in rodents to determine basic efficacy. Then more in-depth experiments have been performed in non-human primates (Macaque & Marmoset). We have, therefore developed systems for both acute and chronic studies and are correlating stimulus data with biophysical models to understand optimal forms of stimulation.