title: Towards high-resolution retinal prostheses with direct optical addressing and inductive telemetry.
abstract: Despite considerable advances in retinal prostheses over the last two decades, the resolution of restored vision has remained severely limited, well below the 20/200 acuity threshold of blindness. Towards drastic improvements in spatial resolution, we present a scalable architecture for retinal prostheses in which each stimulation electrode is directly activated by incident light and powered by a common voltage pulse transferred over a single wireless inductive link.
  
  
  
  The hybrid optical addressability and electronic powering scheme provides separate spatial and temporal control over stimulation, and further provides optoelectronic gain for substantially lower light intensity thresholds than other optically addressed retinal prostheses using passive microphotodiode arrays. The architecture permits the use of high-density electrode arrays with ultra-high photosensitive silicon nanowires, obviating the need for excessive wiring and high-throughput data telemetry. Instead, the single inductive link drives the entire array of electrodes through two wires and provides external control over waveform parameters for common voltage stimulation.
  
  
  
  A complete system comprising inductive telemetry link, stimulation pulse demodulator, charge-balancing series capacitor, and nanowire-based electrode device is integrated and validated ex vivo on rat retina tissue.
  
  
  
  Measurements demonstrate control over retinal neural activity both by light and electrical bias, validating the feasibility of the proposed architecture and its system components as an important first step towards a high-resolution optically addressed retinal prosthesis.
authors.affiliation: Department of Bioengineering, University of California, San Diego, La Jolla, CA, 92093 USA. Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA, 92093 USA.
authors.forename: Sohmyung
authors.initials: S
authors.lastname: Ha
authors.forename: Massoud L
authors.initials: ML
authors.lastname: Khraiche
authors.forename: Abraham
authors.initials: A
authors.lastname: Akinin
authors.forename: Yi
authors.initials: Y
authors.lastname: Jing
authors.forename: Samir
authors.initials: S
authors.lastname: Damle
authors.forename: Yanjin
authors.initials: Y
authors.lastname: Kuang
authors.forename: Sue
authors.initials: S
authors.lastname: Bauchner
authors.forename: Yu-Hwa
authors.initials: YH
authors.lastname: Lo
authors.forename: William R
authors.initials: WR
authors.lastname: Freeman
authors.forename: Gabriel A
authors.initials: GA
authors.lastname: Silva
authors.forename: Gert
authors.initials: G
authors.lastname: Cauwenberghs
mesh_terms: D000818:Animals; D011211:Electric Power Supplies; D004558:Electric Stimulation; D004581:Electronics; D005071:Evoked Potentials; D009924:Organ Culture Techniques; D011474:Prosthesis Design; D051381:Rats; D013686:Telemetry / Q000295:instrumentation*; D057488:Visual Prosthesis; D059015:Wireless Technology