Title: Electrical Stimulating of Retina to Restore Vision
Speaker: Leanne Chan, Assistant Professor, City University of Hong Kong
Time: 10:00-11:00 am, March 27 (Tuesday)
Location: Room 401, School of Microelectronics
Organizer: Prof. Guoxing Wang, School of Microelectronics
1. Talk Abstract
Hundreds of thousands worldwide suffer low vision or no vision due to the outer retinal disease such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP). Recent progress of clinical trials from several retinal prosthesis groups have shown the promise of giving the blind to see again. Despite the loss of the photoreceptors, a significant number of inner retinal neurons survive the outer retinal disease. Activating the intact ganglion cells using electrical stimulation from a retinal prosthesis device can restore functional vision. Simulation results have shown that advanced visual tasks, such as facial recognition and navigation, require a high-resolution implant (600 to 1000 electrodes). However, small electrodes will inject charge at higher current density compared to large electrodes which will result in an unsafe stimulation. This study investigated the safety and efficiency of electrical stimulation from a small electrode in a retinal degenerated animal model. We performed in vivo electrophysiology and morphometric analysis on normal and S334ter-line3 rats in an extensive age range (aged 84-782 days). We correlated the high threshold current required with the low density of surviving ganglion neurons in the same degenerated retina. Our results also showed that short pulse width (<0.5ms) was required to maintain safe stimulation limits in old degenerated retina.
2. Brief Biography
Leanne Lai-hang Chan received her B.Eng. degree in electrical engineering from the University of Hong Kong in 2002. She then went to University of Southern California (USC) for graduate school, earning degrees in Biomedical Engineering (M.S. 2006, Ph.D. 2009) and Electrical Engineering (M.S. 2004). She continued her research in visual system using electrophysiological recording as a tool to study plasticity in mammalian central nervous system (CNS) in a neuroscience research group. She was appointed as Assistant Professor of Electronic Engineering at City University of Hong Kong in December 2011. Her research interests include neural prostheses, electrical stimulation of neural tissue, visual evoked responses, in vivo electrophysiology, and biomimetic implantable systems.