Bio: Yoav Nahum is a cornea specialist and head of outpatient clinics at the Ophthalmology department, Beilinson Hospital. He holds a MD from the Hebrew university of Jerusalem, He completed his Ophthalmology residency in Rabin Medical Center, and a clinical fellowship in Corneal and External eye disease in Villa Igea Hospital, Forli', Italy. Yoav's research is focused at lamellar corneal transplantation techniques. Yoav is the coordinator of joint projects with Afeka College of Engineering at Rabin medical center.
Abstract: Corneal disease a leading cause for blindness worldwide, second only to cataract. In recent years, new techniques of lamellar corneal transplantation have gradually replaced traditional full-thickness corneal transplantation for a majority of patients. Also, several types of corneal prostheses are now available for replacing the diseased cornea, when conventional corneal transplantation is unsuitable. The talk will present these techniques and discuss new technical challenges which they pose.
Bio: Dr. Mandel is an assistant Professor in the School of Optometry and Visual Science and Institute for Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Israel. He is a medical doctor and ophthalmic surgeon and holds a PhD in bioengineering from the Hebrew University, Jerusalem. His research is focused on various ophthalmic technologies aimed at restoration of sight, such as retinal prosthesis, stem cell and combination of these modalities.
Abstract: Current retinal prostheses have been shown to provide useful vision in blind patients by direct electrical activation of the inner retinal neurons. However, inherent limitations of direct neuronal activation (lack of proximity and non-selective neuronal activation), make it challenging to achieve full restoration of vision. We propose a paradigm shift toward sight restoration with a hybrid retinal prosthesis composed of a high-density electrode array (pixel distance down to the cellular size of 10- 15µm), where each individual electrode is coupled with a glutamatergic neuron to create a tight neuron-electrode coupling. Following implantation of the hybrid prosthesis, the glutamatergic neurons integrate and synapse with the host retinal circuits. Patterned electrical stimulation of these glutamatergic neurons by the electrodes modulates glutamate release onto the synapse with the host bipolar cells after which the remaining retinal circuitry is activated in an identical manner to natural vision. We hypothesize that the ultimate electrode-neurons proximity and the low charge neural activation threshold allow for the significant reduction in electrode dimensions and an increase in pixel density as well as the continuous graded potential activation, similarly to the bipolar and photoreceptor cells while the indirect activation of the host retina by glutamatergic neurons, can potentially preserve the natural visual circuits (e.g. ON and OFF).
In this talk I will present our results with stem cell engineering, device fabrication and preliminary electrophysiological data and discuss the many challenges and potential approaches toward the development of hybrid retinal implant.
Bio: Dr. Eli Peli earned a BSc in Electrical Engineering and an MSc in Biomedical Engineering from the Technion Israel Institute of Technology. He received his OD degree from the New England College of Optometry, Boston. Currently Dr. Peli is the Moakley Scholar in Aging Eye Research at Schepens Eye Research Institute, Massachusetts Eye and Ear, and Professor of Ophthalmology at Harvard Medical School. Since 1983 he has been caring for visually impaired patients as the director of the Vision Rehabilitation Service at the New England Medical Center Hospitals. Dr. Peli is a Fellow of the American Academy of Optometry, a Fellow of the Optical Society of America, a Fellow of the SID (Society for Information Display), and a Fellow of the SPIE (The International Society of Optical Engineering). He was presented the 2001 Glenn A. Fry Lecture Award and the 2009 William Feinbloom Award by the American Academy of Optometry, the 2004 Alfred W. Bressler Prize in Vision Science (shared with Dr. R. Massof) by the Jewish Guild for the Blind, the 2006 Pisart Vision Award by the Lighthouse International, the 2009 Alcon Research Institute award (shared with Dr. R. Massof), the 2010 Otto Schade Prize from the SID (Society for Information Display), the 2010 Edwin H Land Medal awarded jointly by the Optical Society of America and the Society for Imaging Science and Technology, and the 2017 Charles Prentice Medal by the American Academy of Optometry. Dr. Peli's principal research interests are image processing in relation to visual function and clinical psychophysics in low vision rehabilitation, image understanding and evaluation of display-vision interaction. He also maintains an interest in oculomotor control and binocular vision. Dr. Peli is a consultant to many companies in the ophthalmic instrumentation area and to manufacturers of head mounted displays (HMD). He served as a consultant on many national committees, including the National Institutes of Health, NASA’s Aviation Operations Systems advisory committee, US Air Force, Department of Veterans Affairs, US Navy Postdoctoral Fellowships Program, US Army Research Labs, and US Department of Transportation, Federal Motor Carrier Safety Administration. Dr. Peli has published more than 200 peer reviewed scientific papers and has been awarded 10 US Patents. He edited a book entitled Visual Models for Target Detection with special emphasis on military applications and co-authored a book entitled Driving with Confidence: A Practical Guide to Driving with Low Vision.
Abstract: Most visual prostheses and sensory substitution devices use a head-mounted video camera to acquire high-resolution wide-field images and convert those to low resolution, low dynamic range and limited field-of-view sensory display. Cluttered natural scenes are difficult to interpret, even when such images are presented as simulated phosphene-like images examined with normal vision. To improve prostheses functionality, we are developing methods to de-clutter object of interest (OI) from background clutter.
In natural vision, background de-cluttering may be achieved by motion parallax caused by the user’s active head movement supported by vestibular and visual fixation reflexes. However, the head-mounted camera in visual prostheses continues to be pointed straight during the translational head movement and does not rotate and fixate the OI as the eyes do during similar head movements. We invented OI locking system enabling effective motion parallax from the head-mounted camera and have shown that approach to be helpful in object recognition under low resolution and narrow field-of-view.
We also developed de-cluttering system based on light-field technology. In a confocal image from the light-field camera, edge filtering keeps the OI and removes the blurred background clutter. We have shown such imaging system to be highly effective in improving the recognition rate at a wide range of resolutions of static binary edge image. In addition, the light-field camera can provide multiple viewpoint images, enabling motion parallax cues from a single integral image, without head movement. This enables generating a data set of object images that may be used to study object recognition with combinations and variations of these techniques.
Bio: Dr. Avi Caspi received his Ph.D. from Weizmann Institute of Science in 2002. He conducted a post-doctoral research at the University of California in Santa Barbara in the field of eye movements. Dr. Caspi joined Second Sight Medical Products, Inc. at 2005. At Second Sight Dr. Caspi developed the image processing and the programming algorithm the Argus II retinal prosthesis.
In 2013, Dr. Caspi joined the Jerusalem College of Technology in Israel. Currently he is the chairman of the Department of Electrical and Electronics Engineering at Jerusalem College of Technology and a consultant to Second Sight Medical Products.
Abstract: Mapping between retinotopic (retina-centered) and spatiotopic (world-centered) coordinate systems is essential for observing a stable perception of a scene across eye movements. The brain uses a combination of several circuits to achieve this goal. It is unknown at what accuracy these brain circuitries map artificial vision induced by a retinal and cortical visual prostheses.
In a series of experiments we quantified the precision of retinotopic to spatiotopic mapping in visual prosthesis. Patients were instructed to place a handheld marker to indicate the location of the percept from the electrical stimulation. The correlation of pupil location at the onset of the stimulation with the head-centered percept location was used to measure the precision of retinotopic to spatiotopic mapping. We have shown that the brain of a blind person can accurately shift the percept from the electrical stimulation to the correct place in the world. Accurate shifting of the line of sight can be used to steer the line of sight of a visual prosthesis to provide enhanced functional sight for the blind.