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| Barboni,M.T.S.; Gomes,B.D.; Souza,G.S.; Rodrigues,A.R.; Ventura,D.F.; Silveira,L.C.L.. |
| The purpose of the present study was to measure contrast sensitivity to equiluminant gratings using steady-state visual evoked cortical potential (ssVECP) and psychophysics. Six healthy volunteers were evaluated with ssVECPs and psychophysics. The visual stimuli were red-green or blue-yellow horizontal sinusoidal gratings, 5° × 5°, 34.3 cd/m2 mean luminance, presented at 6 Hz. Eight spatial frequencies from 0.2 to 8 cpd were used, each presented at 8 contrast levels. Contrast threshold was obtained by extrapolating second harmonic amplitude values to zero. Psychophysical contrast thresholds were measured using stimuli at 6 Hz and static presentation. Contrast sensitivity was calculated as the inverse function of the pooled cone contrast threshold. ssVECP... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Contrast sensitivity; Color vision; Steady-state visual evoked cortical potential; Visual thresholds; Spatial vision; Psychophysics. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2013000200154 |
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| Calandrini,T.S.S.; Miquilini,L.; Laranjeiras-Neto,M.R.; Tongu,M.T.S.; Silva,M.P.; Souza,G.S.; Cortes,M.I.T.. |
| The visual system of women changes during pregnancy. Few reports have addressed the effects of pregnancy on color vision. We aimed to compare the color vision of women in the first, second, and third trimesters of pregnancy. Fifty women were divided into first (n=10), second (n=10), third trimester pregnancy groups (n=10), and non-pregnant group (n=20). We used the Farnsworth D15 and Lanthony desaturated D15 (D15d) tests. The hue ordering quantified the amount of error (C-index) and the chromatic selectivity of the errors (S-index). Bland-Altman analysis was applied to the hue ordering data. No difference was found for Farnsworth D15 test results obtained from the pregnant groups and the non-pregnant group (P<0.0083). For the Lanthony D15 desaturated... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Pregnancy; Visual system; Color vision; Psychophysics. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2019000200606 |
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| Baldo,M.V.C.; Namba,J.. |
| If a dot is flashed in perfect alignment with a pair of dots rotating around the visual fixation point, most observers perceive the rotating dots as being ahead of the flashing dot (flash-lag effect). This perceptual effect has been interpreted to result from the perceptual extrapolation of the moving dots, the differential visual latencies between flashing and moving stimuli, as well as the modulation of attentional mechanisms. Here we attempted to uncouple the attentional effects brought about by the spatial predictability of the flashing dot from the sensory effects dependent on its visual eccentricity. The stimulus was a pair of dots rotating clockwise around the fixation point. Another dot was flashed at either the upper right or the lower left of the... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Attention; Flash-lag effect; Vision; Psychophysics. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002000800014 |
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