April 2011
Volume 52, Issue 14
Free
ARVO Annual Meeting Abstract  |   April 2011
Mobility Experiments With Simulated Vision and sensory substitution of Depth
Author Affiliations & Notes
  • Nick M. Barnes
    Canberra Research Laboratory, NICTA, Canberra, Australia
    College of Engineering,
    Australian National University, Canberra, Australia
  • Paulette Lieby
    Canberra Research Laboratory, NICTA, Canberra, Australia
  • Hugh Dennett
    Canberra Research Laboratory, NICTA, Canberra, Australia
  • Chris McCarthy
    Canberra Research Laboratory, NICTA, Canberra, Australia
  • Nianjun Liu
    Canberra Research Laboratory, NICTA, Canberra, Australia
  • Janine G. Walker
    Centre for Mental Heath Research,
    Australian National University, Canberra, Australia
  • Footnotes
    Commercial Relationships  Nick M. Barnes, Patent related to the approach (P); Paulette Lieby, None; Hugh Dennett, None; Chris McCarthy, None; Nianjun Liu, None; Janine G. Walker, None
  • Footnotes
    Support  Bionic Vision Australia (ARC SRI on Bionic Vision Science and Technology), NICTA (DBCDE, Australian Govt, and ARC), NH&MRC Capacity Building Grant #418020
Investigative Ophthalmology & Visual Science April 2011, Vol.52, 4945. doi:
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    • Get Citation

      Nick M. Barnes, Paulette Lieby, Hugh Dennett, Chris McCarthy, Nianjun Liu, Janine G. Walker; Mobility Experiments With Simulated Vision and sensory substitution of Depth. Invest. Ophthalmol. Vis. Sci. 2011;52(14):4945.

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

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Abstract

Purpose: : Depth information derived from stereo or using active sensors is robust to changes in lighting, contrast, and texture. Depth perception is critical to negotiating overhanging obstacles, which are an important hazard for the visually impaired. We evaluated depth information as a visual representation for mobility for normally-sighted volunteers using simulated prosthetic vision, including in the presence of overhanging obstacles.

Methods: : 4 normally-sighted participants (20/20, Peli-Robson>=0.95) used a mobile artificial vision stimulator set with 30x35 pixels centrally displayed identically to both eyes to navigate a mobility course. A shroud blocked their normal vision. Each phosphene corresponded to the depth of the corresponding visual field. Participants traversed a course viewing color images at full-resolution to establish their preferred walking speed. The course consisted of 6x3 1.5m cells with removable curtains at intersections. Paths were changed to avoid memory effects. Unfamiliar overhanging obstacles of varying size were introduced to some trials. Institutional Ethics Board approval was obtained.

Results: : Depth is an effective representation for mobility: average percentage of preferred walking speed (PPWS) was significantly >50% in trials with (n=24) and without (n=30) obstacles (p<0.05). No significant difference was observed in PPWS when comparing trials with and without obstacles (p=0.24).

Conclusions: : Participants were able to effectively navigating using depth as a visual representation, at greater than half their preferred walking speed. They showed little difficulty in adapting to the substitution of depth, and negotiated suspended obstacles without significant disruption. Depth information shows promise as a visual representation to be used on a retinal prosthesis. We are conducting further trials to compare depth with standard phosphene approaches.

Keywords: retina 
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