Artificial Vision

Title: Challenges in the Arrival of Prosthetic Vision  

Author: Gregg Suaning

Affiliation: Graduate School of Biomedical Engineering, University of South Wales, Australia


The blind are capturing their first glimpses of what the future may bring in the restoration of sight through prosthetic vision. Clear benefits have been demonstrated, but there remains far to go before so-called 'bionic eyes' can restore more than rudimentary vision. This presentation will discuss the challenges the field faces, and some proposed solutions for overcoming these challenges. Strategies include new stimulation paradigms and device configurations to selectively target specific neuronal elements that may lead to more meaningful perceptions.



Title: A Smart Electrode for Retinal Stimulator with the Large Number of Stimulus Electrodes

Author: Jun Ohta

Affiliation: Graduate School of Materials Science, Nara Institute of Science Technology, Japan


This talk presents a smart electrode for a retinal stimulator with the large number of stimulus electrodes. The smart electrode consists of a stimulus electrode combined with a CMOS (complementary metal-oxide-semiconductor) microchip on a flexible substrate. Since each microchip can turn on and off its associated electrode for stimulation through external control circuitry, only small number of interconnection wires are required. In this presentation, the concept, fabrication process and experimental results in vitro and in vivo are shown.



Title: The Design of Subretinal Implant Chip with Shared IrO2 Electrodes and Adaptive Background Current Cancellation Techniques

Author: Chung-Yu Wu

Affiliation: Biomedical Electronics Translational Research Center and Department of Electronics Engineering, National Chiao Tung University, Taiwan.


The circuit and system innovation of a photovoltaic-cell-powered image sensing and current stimulation chip in 180-nm CMOS Image Sensor (CIS) technology for subretinal implant is presented. In the chip, the infra-red (IR) light is incident on photovoltaic cells and pixels whereas visible light is mainly incident on pixels. The Active Pixel Sensor (APS) circuit with the adaptive background current cancellation (ABCC) technique is proposed to cancel the background current generated by the IR on the pixel photodiode. Thus the current generated by the visible light can be integrated transformed to biphasic stimulation currents. A charge pump circuit is designed to increase power supply voltage and thus injection charges. Under the Divisional Power Supply Scheme (DPSS) operation that pixels are turned on individually, the shared electrode scheme is proposed to increase the electrode size. An experimental chip has been designed and fabricated in 180-nm CIS CMOS technology. The chip size is 3mm x 3mm. Post-processes are adopted to deposite IrO2 on top of the on-chip electrodes. Perylene-c passivation is also used to make the implantable chip biocompatible. Finally, future development on subretinal prosthetic systems is discussed.



Title: A High- Density and Flexible Imaging Sensor Retinal Prosthesis

Authors: L.-S. Fan1,5, Z.-T. Lai3, J. Huang1, C. Y. Liu1, Y.T. Cheng1, Y. J. Lai1, L. Chiang1,  H. Chan1, J. Hong1, Y. C. Chen1, Z. Y. Hsiao1, J. Huang1, F. Wu1, K. Yew1, A. Bauquet1, M. Sheu1, H. Chen2,  S. Chen1, F. S. Hsu1, L. J. Lee4, C. G. Cheng1, C. H. Yang3,4, T. C. Chen3, C. M. Yang3,4

Affiliation: 1Iridium Medical Technology Corporation, 2Inst. of Electronics, Natl. Tsing-Hua Univ., 3Dept. of Ophthalmology, National Taiwan University Hospital, 4School of Medicine, National Taiwan University, 5Inst. of NEMS, Natl. Tsing-Hua Univ.


We report a 4,000-pixel high-acuity retinal prosthesis. The retinal prosthesis includes a flexible chip implemented using a 180 nm mixed-signal CMOS Image Sensor technology with a pixel array sensing image and generating bi-phasic electrical stimulations to enable a high visual acuity. This image-sensing retinal prosthesis uses SIROF electrodes 10 um in size and the CMOS retinal chip is made into a contact lens shape conforming to the surface of a human eyeball for a better stimulation resolution and a lower stimulation threshold, and it is passivated for long-term biocompatibility. We use in vivo, ex vivo and in vitro experiments to evaluate the surgery procedure, biocompatibility, thermal and mechanical reliability and the potential efficacy of the retinal prosthesis. Surgery procedure using mini pigs as the animal model has been verified, and preliminary experiments show the biocompatibility (ISO 10993) of the system. The maximum temperature rise has been verified to be within spec. and an accelerated test of the mechanical reliability of the retinal chip equivalent to operating the retinal prosthesis for ~10 years under the extreme mechanical stress condition has shown no sign of mechanical failure. In vivo and ex vivo pattern-reversal EEP experiments are used to assess the potential visual acuity of the implanted high-density retinal prosthesis in the subretinal space. The averaged EEP signal amplitude falls within the background signal between the stripe width of 60 m and 30 m. The corresponding visual acuity is 20/250. The same sub retinal patterned stimulations are used in the ex vivo experiments using whole-cell patch clamping to measure the RGC action potential. In the ex vivo experiments, patch clamped RGC’s can detect, with correlated spiking, the reversal events at a stripe width of 26 m, indicating a potential stripe resolution of up to 20/120 for this retinal prosthesis.

Online Submission Registration Conference Program

 Important Dates

Call for abstracts:
Nov 15,2016

Symposium submission deadline:
Feb 28, 2017

Abstract submission deadline:
Mar 31, 2017 Apr 17, 2017

Early registration deadline:
Mar 31, 2017 Apr 30, 2017

All deadlines are midnight latest time zone on earth.