Factors affecting two-point discrimination in Argus II patients

Ezgi I. Yücel, Roksana Sadeghi, Arathy Kartha, Sandra Rocio Montezuma, Gislin Dagnelie, Ariel Rokem, Geoffrey M. Boynton, Ione Fine, Michael Beyeler

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Two of the main obstacles to the development of epiretinal prosthesis technology are electrodes that require current amplitudes above safety limits to reliably elicit percepts, and a failure to consistently elicit pattern vision. Here, we explored the causes of high current amplitude thresholds and poor spatial resolution within the Argus II epiretinal implant. We measured current amplitude thresholds and two-point discrimination (the ability to determine whether one or two electrodes had been stimulated) in 3 blind participants implanted with Argus II devices. Our data and simulations show that axonal stimulation, lift and retinal damage all play a role in reducing performance in the Argus 2, by either limiting sensitivity and/or reducing spatial resolution. Understanding the relative role of these various factors will be critical for developing and surgically implanting devices that can successfully subserve pattern vision.

Original languageEnglish (US)
Article number901337
JournalFrontiers in Neuroscience
StatePublished - Aug 24 2022

Bibliographical note

Funding Information:
EY was funded through a University of Washington Institute for Neuroengineering and University of Washington eScience Institute Washington Research Foundation Innovation Graduate Fellowship in Neuroengineering Fellowship; NIH-NEI R01-62-5032 (IF and GB) and NIH R00 EY029329 (MB).

Publisher Copyright:
Copyright © 2022 Yücel, Sadeghi, Kartha, Montezuma, Dagnelie, Rokem, Boynton, Fine and Beyeler.


  • current spread
  • modeling
  • psychophysics
  • retina
  • retinal prosthesis
  • sight restoration

PubMed: MeSH publication types

  • Journal Article


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