Retinal degenerative diseases lead to blindness due to loss of the “image capturing” photoreceptors, while neurons in the “image-processing” inner retinal layers are relatively well-preserved. Information can be reintroduced into the visual system by photovoltaic subretinal implants, which convert incident light into electric current and stimulate the secondary retinal neurons.
To provide sufficient light intensity for photovoltaic stimulation while avoiding visual perception by remaining photoreceptors, images captured by a camera are projected onto the retina from augmented-reality glasses using pulsed near-infrared light. This design avoids the use of bulky electronics and wiring, thereby greatly reducing the surgical complexity and enabling scaling the number of photovoltaic pixels to thousands. Many features of the natural retinal signal processing are preserved in this approach, and spatial resolution matches the pixel pitch (so far 100 μm pixels in human patients, and 50 μm in rodents). For a broad acceptance of this technology by patients who lost central vision due to Age-Related Macular Degeneration, visual acuity should exceed 20/100, which requires pixels smaller than 25 μm. I will present a 3-dimensional electro-neural interface scalable to cellular dimensions and discuss the outlook and challenges for future developments.
AP483 Optics and Electronics Seminar Series 2019-20 (Sponsored by Ginzton Laboratory, SPRC, Applied Physics, Physics, and HEPL).
Prof. Palanker studies interactions of electric fields with biological cells and tissues, and develops optical and electronic technologies for diagnostic, therapeutic, surgical, and prosthetic applications, primarily in ophthalmology. In the range of optical frequencies, his studies include laser-tissue interactions with applications to ocular therapy and surgery, and interferometric imaging of neural signals. In the field of electro-neural interfaces, he is developing high-resolution photovoltaic retinal prosthesis for restoration of sight and implants for electronic control of organs.
Several of his developments are in clinical practice world-wide: Pulsed Electron Avalanche Knife (PEAK PlasmaBlade, Medtronic), Patterned Scanning Laser Photocoagulator (PASCAL, Topcon), Femtosecond Laser-Assisted Cataract Surgery (Catalys, J&J), and Neural Stimulator for enhancement of tear secretion (TrueTear, Allergan). Photovoltaic retinal prosthesis for restoration of sight (PRIMA, Pixium Vision) is in clinical trials.
Daniel Palanker is a Professor of Ophthalmology and Director of the Hansen Experimental Physics Laboratory at Stanford. He received an MSc in Physics in 1984 from the State University of Armenia in Yerevan and a PhD in Applied Physics in 1994 from the Hebrew University of Jerusalem, Israel.