July 2019
Volume 60, Issue 9
Open Access
ARVO Annual Meeting Abstract  |   July 2019
A 44 channel suprachoroidal retinal prosthesis: initial psychophysical results
Author Affiliations & Notes
  • Matthew A Petoe
    Bionics Institute, East Melbourne, Victoria, Australia
    Medical Bionics, University of Melbourne, East Melbourne, Victoria, Australia
  • Samuel A Titchener
    Bionics Institute, East Melbourne, Victoria, Australia
    Medical Bionics, University of Melbourne, East Melbourne, Victoria, Australia
  • Mohit N Shivdasani
    Graduate School of Biomedical Engineering, The University of New South Wales, Sydney, New South Wales, Australia
    Bionics Institute, East Melbourne, Victoria, Australia
  • David AX Nayagam
    Bionics Institute, East Melbourne, Victoria, Australia
    Department of Pathology, University of Melbourne, East Melbourne, Victoria, Australia
  • Stephanie B Epp
    Bionics Institute, East Melbourne, Victoria, Australia
  • Joel Villalobos
    Bionics Institute, East Melbourne, Victoria, Australia
    Medical Bionics, University of Melbourne, East Melbourne, Victoria, Australia
  • Nicholas N Sinclair
    Bionics Institute, East Melbourne, Victoria, Australia
    Medical Bionics, University of Melbourne, East Melbourne, Victoria, Australia
  • Chris E Williams
    Bionics Institute, East Melbourne, Victoria, Australia
    Medical Bionics, University of Melbourne, East Melbourne, Victoria, Australia
  • Nick Barnes
    Data61, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Canberra, Australian Capital Territory, Australia
    Research School of Engineering, Australian National University, Canberra, Australian Capital Territory, Australia
  • William G Kentler
    Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria, Australia
  • Maria Kolic
    Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
  • Elizabeth Kate Baglin
    Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
  • Carla J Abbott
    Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
    Opthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
  • Lauren N Ayton
    Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
    Opthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
  • Chi D Luu
    Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
    Opthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
  • Penelope J Allen
    Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
    Opthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
  • Footnotes
    Commercial Relationships   Matthew Petoe, Bionics Institute (P), Bionic Vision Technologies Pty Ltd (F); Samuel Titchener, Bionic Vision Technologies Pty Ltd (F); Mohit Shivdasani, Bionics Institute (P); David Nayagam, Bionics Institute (P), Bionic Vision Technologies Pty Ltd (F); Stephanie Epp, Bionic Vision Technologies Pty Ltd (F); Joel Villalobos, Bionics Institute (P); Nicholas Sinclair, Bionics Institute (P); Chris Williams, Bionics Institute (P), Bionic Vision Technologies Pty Ltd (F); Nick Barnes, Bionic Vision Technologies Pty Ltd (F), Data61, Commonwealth Scientific and Industrial Research Organisation (P); William Kentler, Bionic Vision Technologies Pty Ltd (F); Maria Kolic, Bionic Vision Technologies Pty Ltd (F); Elizabeth Baglin, Bionic Vision Technologies Pty Ltd (F); Carla Abbott, Bionic Vision Technologies Pty Ltd (F); Lauren Ayton, Bionic Eye Technologies Inc (USA) (E); Chi Luu, Bionic Vision Technologies Pty Ltd (F), Centre for Eye Research Australia (P); Penelope Allen, Bionic Vision Technologies Pty Ltd (F), Centre for Eye Research Australia (P)
  • Footnotes
    Support  National Health and Medical Research Council (GNT#1082358); Industry support from Bionic Vision Technologies Pty Ltd; Melbourne Neuroscience Institute Australian Government Research Training Program; Health Investment Grant (Clive and Vera Ramaciotti Foundation); Operational Infrastructure Support from the Victorian Government
Investigative Ophthalmology & Visual Science July 2019, Vol.60, 4993. doi:https://doi.org/
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    • Get Citation

      Matthew A Petoe, Samuel A Titchener, Mohit N Shivdasani, David AX Nayagam, Stephanie B Epp, Joel Villalobos, Nicholas N Sinclair, Chris E Williams, Nick Barnes, William G Kentler, Maria Kolic, Elizabeth Kate Baglin, Carla J Abbott, Lauren N Ayton, Chi D Luu, Penelope J Allen; A 44 channel suprachoroidal retinal prosthesis: initial psychophysical results. Invest. Ophthalmol. Vis. Sci. 2019;60(9):4993. doi: https://doi.org/.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : The success of our clinical trial of a prototype suprachoroidal retinal prosthesis (NCT01603576) in 2014 led us to develop a 44 channel device, with the aim of providing visual information to patients with profound vision loss due to retinitis pigmentosa (RP).

Methods : A 44-channel electrode array was implanted in the suprachoroidal space in eligible patients with advanced retinal dystrophy. After recovery from the surgery they commenced fitting (‘switch-on’) and training with the device. Thresholds for visual perception of phosphenes were assessed using a 2-down 1-up modified staircase procedure. Discriminability of individual phosphenes was assessed using a 3-interval forced choice (3-IFC) ‘odd one out’ discrimination task across pairs of phosphenes selected from retinotopically central and peripheral locations. Functional vision, when using the device with a head-mounted camera (1:1 zoom), was assessed in a square localization task using 10-degree wide high-contrast squares and a 4-alternative forced choice (4-AFC) direction-of-motion task using 7 degree/second moving bars, on a 40-inch touchscreen at arm’s length.

Results : Four patients (age 39-66 years) with rod-cone dystrophy (RP) and with only perception of light vision were recruited. All participants were able to perceive phosphenes. Average phosphene thresholds of all 4 subjects in the first 30 days post switch-on were 182 ± 96 nC, (mean ± S.D., range 38 to 454 nC). Discriminability scores varied according to phosphene selection: pairs involving retinotopically central versus peripheral locations scored 67 to 100% across participants; pairs involving only central locations scored 33 to 100% across participants. Touch precision during the square localization task was significantly better with Device On versus Device Off for the two participants who had been in the study long enough to reach this evaluation time-point at 20 weeks post switch-on. The loci of touch points (mean ± S.D.) spanned 12.7 ± 8.0 degrees (Device On) vs. 33.0 ± 18.6 degrees (Device Off) for P1 and 9.8 ± 5.1 degrees (Device On) vs. 20.8 ± 10.6 degrees (Device Off) for P2 indicating greater precision for Device On. Detection of motion scores ranged from 35 to 100% with Device On, versus 25% with Device Off.

Conclusions : A 44-channel suprachoroidal retinal prosthesis is able to produce discriminable phosphenes and enable functional vision in screen-based tasks.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

 

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