June 2017
Volume 58, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2017
Retinal prosthesis users’ shifts in hand-camera coordination correlate with changes in eye orientation
Author Affiliations & Notes
  • Michael P Barry
    Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States
  • Sophia Diaz-Aguilar
    Neuroscience, Johns Hopkins University, Baltimore, Maryland, United States
  • Liancheng Yang
    Ophthalmology - Lions Vision Center, Johns Hopkins University, Baltimore, Maryland, United States
  • Gislin Dagnelie
    Ophthalmology - Lions Vision Center, Johns Hopkins University, Baltimore, Maryland, United States
  • Footnotes
    Commercial Relationships   Michael Barry, Second Sight Medical Products (F), Second Sight Medical Products (P); Sophia Diaz-Aguilar, None; Liancheng Yang, None; Gislin Dagnelie, eSight Corporation (I), eSight Corporation (C), Quadra Logic Technologies (F), Second Sight Medical Products (C), Second Sight Medical Products (P)
  • Footnotes
    Support  NEI grant T32 EY007143
Investigative Ophthalmology & Visual Science June 2017, Vol.58, 4687. doi:
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    • Get Citation

      Michael P Barry, Sophia Diaz-Aguilar, Liancheng Yang, Gislin Dagnelie; Retinal prosthesis users’ shifts in hand-camera coordination correlate with changes in eye orientation. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4687.

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

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Abstract

Purpose : Determine whether previously observed shifts in hand-camera coordination of retinal prosthesis users correspond with long-term changes in eye orientation.

Methods : Two Argus II retinal prosthesis users performed 3 pointing tasks on 2 different setups every 1–2 weeks over 8 months. One setup used a chinrest with an eye-tracking camera. The second setup allowed the participant to use the Argus II glasses and camera to visually scan a touchscreen with head movements. On the eye-tracking tower, participants were asked to either point to percepts using a touchscreen when electrodes were activated by computer control, or touch the screen directly in front of the nose, when no stimulation was provided. When using the Argus II glasses, participants touched randomly located 4° circular targets as accurately as possible 100–300 times per session.
Eye orientation was measured by tracking the implanted eye’s pupil center and a corneal reflection. Optimal camera alignment positions (OCAPs) were estimated from pointing errors when using the Argus II camera.
Correlated eye-tracking and OCAP data were collected on the same day. Correlation significance was determined using bootstrap resampling of ordinate values. Rates of change were estimated using ordinary least squares regression.

Results : Over the measurement period, subject S1’s OCAP shifted leftward 0.02°/day and downward 0.03°/day. S2’s OCAP shifted downward 0.01°/day. Each of these OCAP-time correlations were significant (p < 10-4).
Horizontal and vertical shifts in OCAPs correlated with changes in average eye orientation for both subjects. S1’s horizontal and S2’s CAP changes correlated best with stimulation-OFF eye orientation changes (S1 horizontal: Pearson’s correlation coefficient r = 0.26, p < 10-6; S2 horizontal: r = 0.07, p < 10-4; S2 vertical: r = 0.08, p < 10-6). S1’s vertical CAP changes correlated best with stimulation-ON eye changes (r = 0.13, p < 10-6).
Subtracting average changes in eye orientation from OCAPs for S1 reduced the horizontal rate of change by 47% and vertical by 104%. S2’s OCAP vertical rate of change was corrected by 103%.

Conclusions : Changes in hand-camera coordination correlate with long-term changes in average eye orientation. Eye tracking integrated into a visual prosthesis may be used to estimate and at least partially compensate for changes in hand-camera coordination over time.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

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