June 2021
Volume 62, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2021
Detailed binocular scotoma mapping reveals adaptive saccades in macular degeneration
Author Affiliations & Notes
  • Cécile Vullings
    Smith-Kettlewell Eye Research Institute, San Francisco, California, United States
  • Zachary Lively
    Smith-Kettlewell Eye Research Institute, San Francisco, California, United States
  • Preeti Verghese
    Smith-Kettlewell Eye Research Institute, San Francisco, California, United States
  • Footnotes
    Commercial Relationships   Cécile Vullings, None; Zachary Lively, None; Preeti Verghese, None
  • Footnotes
    Support  Fulbright grant (C.V.), Rachel C. Atkinson & C.V. Starr postdoctoral fellowship (C.V.), and NIH grant NIH R01 EY029730 (P.V.)
Investigative Ophthalmology & Visual Science June 2021, Vol.62, 3546. doi:
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    • Get Citation

      Cécile Vullings, Zachary Lively, Preeti Verghese; Detailed binocular scotoma mapping reveals adaptive saccades in macular degeneration. Invest. Ophthalmol. Vis. Sci. 2021;62(8):3546.

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

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Abstract

Purpose : When the scotoma is binocular in macular degeneration (MD), objects can be obscured and individuals are often unaware that they are missing information. Current methods of detailed scotoma mapping are mainly monocular; very few methods offer the same level of precision for binocular scotoma. We propose a new method to map precisely the binocular scotoma and use this detailed map to investigate adaptive saccade strategies in visual search.

Methods : Six individuals with MD and 4 age-matched controls participated in our study. First, we measured the peripheral fixation locus, the location of the foveal pit and the extent of the monocular scotoma in each eye using an OCT/SLO. Then, we extensively mapped the monocular and binocular scotomata with an eyetracker while fixation was carefully monitored. Participants fixated a cross and responded whenever they detected a briefly flashed dot. The flashes were first presented on a coarse grid, and then at manually selected points to examine the edges of the scotoma in finer detail (Fig 1A). Finally, participants completed a visual search task where they had to report the number of Gaussian blobs randomly distributed across a natural scene.

Results : Monocular scotomata measured in the SLO and eyetracker were highly similar (mean d’ value = 2.54), validating the eyetracking method to map scotoma. Moreover, all participants used clustered fixation loci corresponding to their dominant preferred fixation locus. Importantly, the binocular map from the eyetracker was consistent with the overlap of the monocular scotoma profiles from the SLO. In the visual-search task, all participants made mostly horizontal saccades, but individuals with MD made significantly more saccades toward their scotoma than controls for the same directions (Fig 1B). However, their median amplitude was smaller, and therefore a single saccade was not sufficient to fully uncover the region hidden by a large scotoma (Fig 1C). Instead of making sequential saccades toward the scotoma, participants frequently made backward saccades directed to newly uncovered regions.

Conclusions : Our eyetracker method offers a reliable and sensitive tool for measuring the functional binocular scotomata. Determining the location and extent of the binocular scotoma with respect to the fixation locus reveals ocumolotor adaptations in daily life such as backward saccades to explore newly uncovered regions during visual search.

This is a 2021 ARVO Annual Meeting abstract.

 

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