May 2003
Volume 44, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2003
Lateral Interactions in Peripheral Vision
Author Affiliations & Notes
  • R.G. Giorgi
    Schepens Eye Research Institute, Harvard Medical School, Boston, MA, United States
  • G.P. Soong
    Optometry & Vision Science, University of Auckland, Auckland, New Zealand
  • R.L. Woods
    Optometry & Vision Science, University of Auckland, Auckland, New Zealand
  • E. Peli
    Optometry & Vision Science, University of Auckland, Auckland, New Zealand
  • Footnotes
    Commercial Relationships  R.G. Giorgi, None; G.P.Y. Soong, None; R.L. Woods, None; E. Peli, None.
  • Footnotes
    Support  NIH Grants EY05957 and EY12890
Investigative Ophthalmology & Visual Science May 2003, Vol.44, 4092. doi:
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    • Get Citation

      R.G. Giorgi, G.P. Soong, R.L. Woods, E. Peli; Lateral Interactions in Peripheral Vision . Invest. Ophthalmol. Vis. Sci. 2003;44(13):4092.

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

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Abstract

Abstract: : Purpose: When viewed foveally, contrast detection of a Gabor patch (target) is facilitated by collinear, displaced high-contrast Gabor masks (flankers). Polat and Sagi (1994, Proc. Nat. Acad. Sci., 91, 1206) reported that the same phenomenon occurred in the periphery, but no data was presented. Williams and Hess (1998, J. Opt. Soc. Am. A, 15, 2046) found no facilitation in a limited number of conditions tested using a spatial 2AFC paradigm. In the present study, we measured contrast detection in peripheral vision in an effort to resolve this conflict in the literature. Methods: Five normally-sighted subjects participated in temporal and spatial 2AFC experiments. Experiment 1 examined the effect of eccentric viewpoint (2°, 4°, 6° & 12°) on facilitation using 4 test-flanker distances (2, 4, 6 & 8λ, where λ=cpd-1) and a spatial frequency of 2cpd. Experiment 2 examined the effect of spatial frequency (1, 2, 4, 6 and 8cpd). Experiment 3 measured the effect of flanker contrast (10, 20, 40 & 80%). Experiment 4 tested the effect of global orientation of the stimulus pattern (vertical or horizontal). In experiments 2, 3 and 4, eccentricity was 4° and test-flanker distance was 4λ. Results: Facilitation was found to occur in many but not all conditions. Maximum facilitation occured at a test-flanker distance of 4-6λ, whereas maximum facilitation occurs at 2-3λ in central vision. Facilitation varied between subjects and with spatial frequency. Flanker contrast had no effect over the range evaluated. Equal facilitation was found for both global arrangements of the stimulus pattern. Conclusion: Facilitation of contrast detection does occur in the near periphery of normally-sighted subjects, although the magnitude of the effect is less than found in central vision. The value of such facilitation for persons with central vision impairment needs to be examined.

Keywords: contrast sensitivity • spatial vision • low vision 
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