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Marques DN, Gomes AE, Linhares JMM, Nascimento SMC. Discrimination of natural colors in anomalous trichromacy and the effects of EnChroma and Vino filters. OPTICS EXPRESS 2023; 31:18075-18087. [PMID: 37381526 DOI: 10.1364/oe.451326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 05/19/2022] [Indexed: 06/30/2023]
Abstract
It is still unclear how well anomalous trichromats discriminate natural colors and whether commercial spectral filters improve performance in these conditions. We show that anomalous trichromats have good color discrimination with colors drawn from natural environments. It is only about 14% poorer, on average, than normal trichromats in our sample of thirteen anomalous trichromats. No measurable effect of the filters on discrimination was found, even after 8 hours of continuous use. Computations of cone and post-receptoral signals show only a modest increase in medium-to-long-wavelength difference signals, which may explain the absent effect of the filters.
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Álvaro L, Linhares JMM, Formankiewicz MA, Waugh SJ. Coloured filters can simulate colour deficiency in normal vision but cannot compensate for congenital colour vision deficiency. Sci Rep 2022; 12:11140. [PMID: 35778454 PMCID: PMC9249763 DOI: 10.1038/s41598-022-13877-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 05/30/2022] [Indexed: 11/28/2022] Open
Abstract
Red-green colour vision deficiency (CVD) affects ~ 4% of Caucasians. Notch filters exist to simulate CVD when worn by colour vision normal (CVN) observers (simulation tools), or to improve colour discrimination when worn by CVD observers (compensation tools). The current study assesses effects of simulation (Variantor) and compensation (EnChroma) filters on performance in a variety of tasks. Experiments were conducted on 20 CVN and 16 CVD participants under no-filter and filter conditions (5 CVN used Variantor; 15 CVN and 16 CVD used EnChroma). Participants were tested on Ishihara and Farnsworth-Munsell 100 hue tests, CVA-UMinho colour discrimination and colour naming tasks and a board-game colour-sorting task. Repeated-measures ANOVAs found Variantor filters to significantly worsen CVN performance, mimicking protanopia. Mixed-model and repeated-measures ANOVAs demonstrate that EnChroma filters do not significantly enhance performance in CVD observers. Key EnChroma results were replicated in 8 CVD children (Ishihara test) and a sub-sample of 6 CVD adults (CVA-UMinho colour discrimination and colour naming tasks) for a smaller stimulus size. Pattern similarity exists across hue for discrimination thresholds and naming errors. Variantor filters are effective at mimicking congenital colour vision defects in CVN observers for all tasks, however EnChroma filters do not significantly compensate for CVD in any.
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Affiliation(s)
- Leticia Álvaro
- Anglia Vision Research, School of Psychology and Sport Science, Anglia Ruskin University, East Road, Cambridge, CB1 1PT, UK. .,Dpto. Psicología experimental, Procesos cognitivos y Logopedia, Universidad Complutense de Madrid, 28883, Pozuelo de Alarcón, Spain.
| | - João M M Linhares
- Physics Centre of Minho and Porto Universities (CF-UM-UP), Gualtar Campus, University of Minho, 4710-057, Braga, Portugal
| | - Monika A Formankiewicz
- Anglia Vision Research, School of Psychology and Sport Science, Anglia Ruskin University, East Road, Cambridge, CB1 1PT, UK
| | - Sarah J Waugh
- Anglia Vision Research, School of Psychology and Sport Science, Anglia Ruskin University, East Road, Cambridge, CB1 1PT, UK.,Centre for Vision Across the Life Span, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK
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Salomão RC, Martins ICVDS, Risuenho BBO, Guimarães DL, Silveira LCL, Ventura DF, Souza GS. Visual evoked cortical potential elicited by pseudoisochromatic stimulus. Doc Ophthalmol 2019; 138:43-54. [PMID: 30617670 DOI: 10.1007/s10633-018-09669-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/31/2018] [Indexed: 11/25/2022]
Abstract
PURPOSE Visual evoked cortical potentials (VECPs) are useful for investigating the mechanisms and dysfunctions of color vision. Chromatic sinusoidal gratings are generally used to elicit VECPs, but they require long psychophysical measurements to match the perceptual luminance between their stripes. An alternative method is to use pseudoisochromatic stimuli, which makes use of luminance noise to mask luminance clues and force the target perception to be dependent on chromatic contrast. In this study, we compared VECPs generated by sinusoidal gratings and pseudoisochromatic gratings. Contrary to chromatic sinusoidal gratings, pseudoisochromatic stimuli do not require the use of previous methods to find the equiluminance of the stimulus. METHODS Normal trichromats were recruited to be tested with red-green chromatic sinusoidal gratings and pseudoisochromatic gratings presented by pattern onset-offset and pattern reversal modes in five spatial frequencies. In addition, we also tested four different chromatic contrast pairs in pattern onset-offset mode presentation in five trichromats and one colorblind subject (deuteranope). RESULTS Pattern onset-offset VECPs elicited by sinusoidal gratings had a larger amplitude than those obtained with pseudoisochromatic stimuli, whereas pattern reversal VECPs elicited by pseudoisochromatic gratings had similar amplitudes compared to those elicited by sinusoidal gratings. We found no difference between the VECP amplitudes elicited by sinusoidal and pseudoisochromatic gratings containing different chromatic contrast. Color-blind subjects displayed absent or small responses to the stimuli. CONCLUSION Pseudoisochromatic stimulus can be an alternative stimulus to generate VECPs dominated by the chromatic mechanism.
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Affiliation(s)
- Railson Cruz Salomão
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil
- Núcleo de Medicina Tropical, Universidade Federal do Pará, Av Generalíssimo Deodoro 92, Umarizal, Belém, Pará, 66055240, Brazil
| | | | | | - Diego Leite Guimarães
- Núcleo de Medicina Tropical, Universidade Federal do Pará, Av Generalíssimo Deodoro 92, Umarizal, Belém, Pará, 66055240, Brazil
| | - Luiz Carlos Lima Silveira
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil
- Núcleo de Medicina Tropical, Universidade Federal do Pará, Av Generalíssimo Deodoro 92, Umarizal, Belém, Pará, 66055240, Brazil
- Universidade CEUMA, São Luiz, Maranhão, Brazil
| | | | - Givago Silva Souza
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
- Núcleo de Medicina Tropical, Universidade Federal do Pará, Av Generalíssimo Deodoro 92, Umarizal, Belém, Pará, 66055240, Brazil.
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de Loureiro TMG, Brodeur K, Schade G, Brito FAC, Salomao RC, Miquilini L, Bonci DMO, Baran LCP, Hauzman E, Goulart PRK, Cortes MIT, Ventura DF, Fitzgerald MEC, Souza GS. Effect of the Decrease in Luminance Noise Range on Color Discrimination of Dichromats and Trichromats. Front Behav Neurosci 2018; 12:292. [PMID: 30532699 PMCID: PMC6265314 DOI: 10.3389/fnbeh.2018.00292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 11/12/2018] [Indexed: 11/23/2022] Open
Abstract
Color vision assessment can be done using pseudoisochromatic stimuli, which has a luminance noise to eliminate brightness differences between the target and background of the stimulus. It is not clear the influence of the luminance noise on color discrimination. We investigated the effect of change in the luminance noise limits on color discrimination. Eighteen trichromats and ten congenital dichromats (eight protans, two deutans) had their color vision evaluated by the Cambridge Colour Test, and were genetically tested for diagnostic confirmation. The stimuli were composed of a mosaic of circles in a 5° circular field. A subset of the circles differed in chromaticity from the remaining field, forming a letter C. Color discrimination was estimated in stimulus conditions differing in luminance noise range: (i) 6–20 cd/m2; (ii) 8–18 cd/m2; (iii) 10–16 cd/m2; and (iv) 12–14 cd/m2. Six equidistant luminance values were used within the luminance noise limits with the mean stimulus luminance maintained constant under all conditions. A four-alternative, forced-choice method was applied to feed a staircase procedure to estimate color discrimination thresholds along eight chromatic axes. An ellipse model was adjusted to the eight color discrimination thresholds. The parameters of performance were threshold vector lengths and the ellipse area. Results were compared using the Kruskal-Wallis test with a significance level of 5%. The linear function model was applied to analyze the dependence of the discrimination parameters on the noise luminance limits. The first derivative of linear function was used as an indicator of the rate of change in color discrimination as a function of luminance noise changes. The rate of change of the ellipse area as a function of the luminance range in dichromats was higher than in trichromats (p < 0.05). Significant difference was also found for individual thresholds in half of the axes we tested. Luminance noise had a greater effect on color discrimination ability of dichromats than the trichromats, especially when the chromaticities were close to their protan and deutan color confusion lines.
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Affiliation(s)
| | - Ketan Brodeur
- University of Michigan, Ann Arbor, MI, United States
| | | | | | | | - Leticia Miquilini
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | | | | | - Einat Hauzman
- Instituto de Psicologia, Universidade de São Paulo, São Paulo, Brazil
| | | | | | - Dora Fix Ventura
- Instituto de Psicologia, Universidade de São Paulo, São Paulo, Brazil
| | - Malinda E C Fitzgerald
- Southern College of Optometry, Memphis, TN, United States.,Biology, Didactic Faculty and Anatomy and Neurobiology, Christian Brothers University, Memphis, TN, United States.,University of Tennessee Health Science Center, Memphis, TN, United States
| | - Givago Silva Souza
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil.,Núcleo de Medicina Tropical, Universidade Federal do Pará, Belém, Brazil
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Miquilini L, Walker NA, Odigie EA, Guimarães DL, Salomão RC, Lacerda EMCB, Cortes MIT, de Lima Silveira LC, Fitzgerald MEC, Ventura DF, Souza GS. Influence of Spatial and Chromatic Noise on Luminance Discrimination. Sci Rep 2017; 7:16944. [PMID: 29208981 PMCID: PMC5717058 DOI: 10.1038/s41598-017-16817-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 11/17/2017] [Indexed: 11/21/2022] Open
Abstract
Pseudoisochromatic figures are designed to base discrimination of a chromatic target from a background solely on the chromatic differences. This is accomplished by the introduction of luminance and spatial noise thereby eliminating these two dimensions as cues. The inverse rationale could also be applied to luminance discrimination, if spatial and chromatic noise are used to mask those cues. In this current study estimate of luminance contrast thresholds were conducted using a novel stimulus, based on the use of chromatic and spatial noise to mask the use of these cues in a luminance discrimination task. This was accomplished by presenting stimuli composed of a mosaic of circles colored randomly. A Landolt-C target differed from the background only by the luminance. The luminance contrast thresholds were estimated for different chromatic noise saturation conditions and compared to luminance contrast thresholds estimated using the same target in a non-mosaic stimulus. Moreover, the influence of the chromatic content in the noise on the luminance contrast threshold was also investigated. Luminance contrast threshold was dependent on the chromaticity noise strength. It was 10-fold higher than thresholds estimated from non-mosaic stimulus, but they were independent of colour space location in which the noise was modulated. The present study introduces a new method to investigate luminance vision intended for both basic science and clinical applications.
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Affiliation(s)
- Leticia Miquilini
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil
| | - Natalie A Walker
- University of Tennessee Health Science Center, Memphis, TN, United States of America
| | - Erika A Odigie
- Christian Brother's University, Memphis, TN, United States of America
| | | | | | | | | | - Luiz Carlos de Lima Silveira
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.,Núcleo de Medicina Tropical, Universidade Federal do Pará, Belém, Pará, Brazil.,Universidade Ceuma, São Luiz, Maranhão, Brazil
| | - Malinda E C Fitzgerald
- University of Tennessee Health Science Center, Memphis, TN, United States of America.,Christian Brother's University, Memphis, TN, United States of America
| | - Dora Fix Ventura
- Instituto de Psicologia, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Givago Silva Souza
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil. .,Núcleo de Medicina Tropical, Universidade Federal do Pará, Belém, Pará, Brazil.
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Álvaro L, Linhares JMM, Moreira H, Lillo J, Nascimento SMC. Robust colour constancy in red-green dichromats. PLoS One 2017; 12:e0180310. [PMID: 28662218 PMCID: PMC5491172 DOI: 10.1371/journal.pone.0180310] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 06/13/2017] [Indexed: 11/19/2022] Open
Abstract
Colour discrimination has been widely studied in red-green (R-G) dichromats but the extent to which their colour constancy is affected remains unclear. This work estimated the extent of colour constancy for four normal trichromatic observers and seven R-G dichromats when viewing natural scenes under simulated daylight illuminants. Hyperspectral imaging data from natural scenes were used to generate the stimuli on a calibrated CRT display. In experiment 1, observers viewed a reference scene illuminated by daylight with a correlated colour temperature (CCT) of 6700K; observers then viewed sequentially two versions of the same scene, one illuminated by either a higher or lower CCT (condition 1, pure CCT change with constant luminance) or a higher or lower average luminance (condition 2, pure luminance change with a constant CCT). The observers' task was to identify the version of the scene that looked different from the reference scene. Thresholds for detecting a pure CCT change or a pure luminance change were estimated, and it was found that those for R-G dichromats were marginally higher than for normal trichromats regarding CCT. In experiment 2, observers viewed sequentially a reference scene and a comparison scene with a CCT change or a luminance change above threshold for each observer. The observers' task was to identify whether or not the change was an intensity change. No significant differences were found between the responses of normal trichromats and dichromats. These data suggest robust colour constancy mechanisms along daylight locus in R-G dichromacy.
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Affiliation(s)
- Leticia Álvaro
- Anglia Vision Research, Department of Vision and Hearing Sciences, Anglia Ruskin University, Cambridge, United Kingdom
- Facultad de Psicología, Universidad Complutense de Madrid, Pozuelo de Alarcón, España
- * E-mail:
| | | | - Humberto Moreira
- Facultad de Psicología, Universidad Complutense de Madrid, Pozuelo de Alarcón, España
| | - Julio Lillo
- Facultad de Psicología, Universidad Complutense de Madrid, Pozuelo de Alarcón, España
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