May 2008
Volume 49, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2008
Red-Green Spatial Contrast Sensitivity Function: Comparison Between Steady State Visual Evoked Potential and Psychophysical Measurements
Author Affiliations & Notes
  • M. T. Barboni
    Neurociências e Comportamento and Departamento de Psicologia Experimental, Universidade de São Paulo, São Paulo, Brazil
  • G. S. Souza
    Departamento de Fisiologia,
    Universidade Federal do Pará, Belém, Brazil
  • B. D. Gomes
    Departamento de Fisiologia,
    Universidade Federal do Pará, Belém, Brazil
  • A. R. Rodrigues
    Departamento de Fisiologia,
    Universidade Federal do Pará, Belém, Brazil
  • C. A. Saito
    Departamento de Fisiologia,
    Universidade Federal do Pará, Belém, Brazil
  • D. F. Ventura
    Neurociências e Comportamento and Departamento de Psicologia Experimental, Universidade de São Paulo, São Paulo, Brazil
  • L. C. L. Silveira
    Departamento de Fisiologia and Núcleo de Medicina Tropical,
    Universidade Federal do Pará, Belém, Brazil
  • Footnotes
    Commercial Relationships  M.T. Barboni, None; G.S. Souza, None; B.D. Gomes, None; A.R. Rodrigues, None; C.A. Saito, None; D.F. Ventura, None; L.C.L. Silveira, None.
  • Footnotes
    Support  CAPES, CNPq, FAPESP, FUNTEC, and FINEP-IBN Net
Investigative Ophthalmology & Visual Science May 2008, Vol.49, 3315. doi:https://doi.org/
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      M. T. Barboni, G. S. Souza, B. D. Gomes, A. R. Rodrigues, C. A. Saito, D. F. Ventura, L. C. L. Silveira; Red-Green Spatial Contrast Sensitivity Function: Comparison Between Steady State Visual Evoked Potential and Psychophysical Measurements. Invest. Ophthalmol. Vis. Sci. 2008;49(13):3315. doi: https://doi.org/.

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

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Abstract
 
Purpose:
 

To measure chromatic contrast sensitivity function (CSF) using steady state visual evoked potential (ssVEP) and to compare ssVEP and psychophysical CSF.

 
Methods:
 

Five normal trichromats (26.6 ± 1.7 years old) were monocularly tested. A red-green horizontal isoluminant grating (CIE 1976: u’= 0.288, v’= 0.480 and u’= 0.15, v’= 0.480) was presented at 5 Hz as a 5º diameter circle against a background of mean luminance (34.3 cd/m²) and mean chromaticity of the grating. Four spatial frequencies (0.4 - 2 cpd), were used. Heterochromatic Flicker Photometry protocol at 20 Hz was used to obtain the isoluminance. Psychophysical thresholds were measured with method of adjustments using the same spatio-temporal configuration as used in ssVEP as well as static presentation. ssVEP data were analyzed with a Fast Fourier Transform protocol. Second harmonic amplitude was plotted against the log pooled cone contrast and the data were fitted with a regression line. Contrast sensitivity was expressed as the reciprocal of the contrast value corresponding to the extrapolation of the fitted line to zero amplitude.

 
Results:
 

All CSFs were low-pass functions. The mean CSFs are shown in Table 1. The results of the dynamic psychophysical CSF agree with the electrophysiological CSF, while the static psychophysical CSF differed at all spatial frequencies (ANOVA p<0.05).

 
Conclusions:
 

The red-green CSF obtained using ssVEP was better correlated with the dynamic than with the static psychophysical CSF. Static thresholds were elevated in comparison to both dynamic CSFs. The results suggest that the second harmonic for the reversal pattern mode may reflect P pathway activity.  

 
Keywords: color vision • contrast sensitivity • pattern vision 
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