A New Interpretation of the Relative Central Scotoma for Blue Stimuli under Photopic Conditions

  • R. Lakowski
  • P. Dunn
Part of the Documenta Ophthalmologica Proceedings Series book series (DOPS, volume 19)

Abstract

In an earlier paper a relative central scotoma for a blue stimulus as reported by Verriest and Israel and others was not found. The reason was thought to be a combination of luminance and target size differences between the experimenters, involving the phenomenon of summation.

A Goldmann perimeter identical to Verriest’s was used to examine six subjects on the Goldmann targets at three different target sizes and at the luminances used by Verriest.

Results show duplication of Verriest’s results when his method is followed, however this involves changing both size and maximum target luminance from colour to colour. When photometrically equated targets are used, and only target size is varied, from colour to colour, it becomes apparent that the foveal sensitivity for the blue target is no different than for the other targets, and in fact it is the parafoveal thresholds which are higher for the blue target. These results show an increase in sensitivity to a short wavelength stimulus with a dominant wavelength λD 454 nm, outside the fovea, the effect being maximal at the parafovea. This effect was absent in our study using a target of λD 474 nm, at a higher luminance value and a smaller target size.

Keywords

Retina Eter Scotoma 

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Copyright information

© Dr W. Junk bv Publishers 1979

Authors and Affiliations

  • R. Lakowski
    • 1
  • P. Dunn
    • 1
  1. 1.Visual Laboratory Department of PsychologyThe University of British ColumbiaVancouverCanada

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