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Foster DH, Nascimento SM. Little information loss with red-green color deficient vision in natural environments. iScience 2023; 26:107421. [PMID: 37593460 PMCID: PMC10428128 DOI: 10.1016/j.isci.2023.107421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 05/10/2023] [Accepted: 07/13/2023] [Indexed: 08/19/2023] Open
Abstract
Inherited color vision deficiency affects red-green discrimination in about one in twelve men from European populations. Its effects have been studied mainly in primitive foraging but also in detecting blushing and breaking camouflage. Yet there is no obvious relationship between these specific tasks and vision in the real world. The aim here was to quantify the impact of color vision deficiency by estimating computationally the information available to observers about colored surfaces in natural scenes. With representative independent sets of 50 and 100 hyperspectral images, estimated information was found to be only a little less in red-green color vision deficiency than in normal trichromacy. Colorimetric analyses revealed the importance of large lightness variations within scenes, small redness-greenness variations, and uneven frequencies of different colored surfaces. While red-green color vision deficiency poses challenges in some tasks, it has much less effect on gaining information from natural environments.
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Affiliation(s)
- David H. Foster
- Department of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL, UK
| | - Sérgio M.C. Nascimento
- Physics Center of Minho and Porto Universities (CF-UM-UP), University of Minho, 4710-057 Braga, Portugal
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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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Arnegard S, Baraas RC, Neitz J, Hagen LA, Neitz M. Limitation of standard pseudoisochromatic plates in identifying colour vision deficiencies when compared with genetic testing. Acta Ophthalmol 2022; 100:805-812. [PMID: 35113505 PMCID: PMC9614865 DOI: 10.1111/aos.15103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 11/12/2021] [Accepted: 01/20/2022] [Indexed: 12/22/2022]
Abstract
PURPOSE The Ishihara pseudoisochromatic (PIC) plate test is the most used test for identifying red-green colour-deficient individuals, but it is not known how the Ishihara results compare with that of genetics testing. Here, the outcome of genotype analysis of OPN1LW and OPN1MW was compared with that of the Ishihara (24-plate ed., 1964) and the Hardy-Rand-Rittler (4th ed. 2002) PIC plate tests. METHODS Healthy participants with normal habitual visual acuity (n = 454, 16-24 years; 193 males; logMAR ≤ 0.00) gave saliva samples for opsin gene analysis and performed the two PIC plate tests as part of a cross-sectional study. The criteria for failing the PIC tests were according to manufacturers' instructions. DNA was extracted and used in genotyping assays of OPN1LW and OPN1MW genes from each participant using the Agena MassArray genotyping system. RESULTS Ten male (5.2%) and 3 (1.1%) female participants were identified as red-green colour deficient based on PIC tests alone. The combination of MassArray and PIC test results identified 10.4% of male and 0.8% of female participants to be colour deficient (males: 0.5% protan and 9.9% deutan; females: 0.8% deutan). Hardy-Weinberg calculations based on male frequencies from combining the MassArray and the PIC test results gave female frequency estimates of colour deficiency and carriers closely matching measured frequencies. CONCLUSIONS MassArray identified twice as many colour-deficient males as identified from PIC tests alone. Combining results from MassArray and the PIC tests proves to be more reliable than any single test at correctly identifying red-green colour-deficient individuals and carriers.
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Affiliation(s)
- Solveig Arnegard
- National Centre for Optics, Vision and Eye Care, Faculty of Health and Social Sciences, University of South-Eastern Norway, Kongsberg, Norway
| | - Rigmor C. Baraas
- National Centre for Optics, Vision and Eye Care, Faculty of Health and Social Sciences, University of South-Eastern Norway, Kongsberg, Norway
| | - Jay Neitz
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
| | - Lene A. Hagen
- National Centre for Optics, Vision and Eye Care, Faculty of Health and Social Sciences, University of South-Eastern Norway, Kongsberg, Norway
| | - Maureen Neitz
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
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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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Nascimento SMC, Foster DH. Information gains from commercial spectral filters in anomalous trichromacy. OPTICS EXPRESS 2022; 30:16883-16895. [PMID: 36221522 DOI: 10.1364/oe.451407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 04/19/2022] [Indexed: 06/16/2023]
Abstract
Red-green color discrimination is compromised in anomalous trichromacy, the most common inherited color vision deficiency. This computational analysis tested whether three commercial optical filters with medium-to-long-wavelength stop bands increased information about colored surfaces. The surfaces were sampled from 50 hyperspectral images of outdoor scenes. At best, potential gains in the effective number of surfaces discriminable solely by color reached 9% in protanomaly and 15% in deuteranomaly, much less than with normal trichromacy. Gains were still less with lower scene illumination and more severe color vision deficiency. Stop-band filters may offer little improvement in objective real-world color discrimination.
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Mushtaq F, Baraas RC, Al-Saud LM, Mirghani I, van der Zee C, Yates E, Keeling A, Mon-Williams MA, Manogue M. Should prospective dental students be screened for colour vision deficits? Br Dent J 2018; 221:227-8. [PMID: 27608568 DOI: 10.1038/sj.bdj.2016.633] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2016] [Indexed: 11/09/2022]
Abstract
A perennial question in dental education is: what skills and aptitudes should be assessed in prospective dental students? Intellectual capacity and manual dexterity understandably rank highly, but are there minimum thresholds for visual perception that applicants need be able to demonstrate before they enter the profession? We have recently flagged this issue with regard to the thresholds of stereoscopic acuity required for a dentist when operating on teeth. In the present article, we highlight the issue of identifying a minimum acceptable level of colour vision.
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Affiliation(s)
- F Mushtaq
- School of Psychology, Faculty of Medicine and Health, University of Leeds, Leeds, West Yorkshire
| | - R C Baraas
- Department of Optometry and Visual Science, National Centre for Optics, Vision and Eye Care, University College of Southeast Norway, Kongsberg, Norway
| | - L M Al-Saud
- School of Dentistry, Faculty of Medicine and Health, University of Leeds, Leeds, West Yorkshire
| | - I Mirghani
- School of Dentistry, Faculty of Medicine and Health, University of Leeds, Leeds, West Yorkshire
| | - C van der Zee
- School of Dentistry, Faculty of Medicine and Health, University of Leeds, Leeds, West Yorkshire
| | - E Yates
- School of Dentistry, The University of Western Australia, Crawley, Australia
| | - A Keeling
- School of Dentistry, Faculty of Medicine and Health, University of Leeds, Leeds, West Yorkshire
| | - M A Mon-Williams
- School of Psychology, Faculty of Medicine and Health, University of Leeds, Leeds, West Yorkshire.,Department of Optometry and Visual Science, National Centre for Optics, Vision and Eye Care, University College of Southeast Norway, Kongsberg, Norway.,Bradford Institute of Health Research, Bradford Teaching Hospitals NHS Trust, Bradford
| | - M Manogue
- School of Dentistry, Faculty of Medicine and Health, University of Leeds, Leeds, West Yorkshire
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de Almeida VMN, Fiadeiro PT, Nascimento SMC. Effect of Scene Dimensionality on Colour Constancy with Real Three-Dimensional Scenes and Objects. Perception 2010; 39:770-9. [DOI: 10.1068/p6485] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The effect of scene dimensionality on colour constancy was tested with real scenes and objects. Observers viewed a three-dimensional (3-D) scene, or its two-dimensional (2-D) planar projection, through a large beam-splitter that projected the virtual image of a real test object (a cube or its 2-D projection) so that it appeared part of the scene. Test object and scene could be illuminated independently with high chromatic precision. In each trial, the illuminance of the scene changed abruptly from 25 000 K to 6700 K and the illuminant of the test object changed either consistently or inconsistently with it by a variable quantifiable amount. Observers had to decide whether the test object underwent a change in its materials. The extent of constancy obtained in the experiment was not influenced by scene dimensionality and varied significantly with the colour of the test object. These results suggest that color constancy in the conditions tested here may be determined by local spectral quantities.
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Affiliation(s)
| | | | - Sérgio M C Nascimento
- Department of Physics, Gualtar Campus, University of Minho, 4710-057 Braga, Portugal
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Baraas RC, Foster DH, Amano K, Nascimento SMC. Color constancy of red-green dichromats and anomalous trichromats. Invest Ophthalmol Vis Sci 2009; 51:2286-93. [PMID: 19892868 DOI: 10.1167/iovs.09-4576] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose. Color-vision deficiency is associated with abnormalities in color matching and color discrimination, but its impact on the ability of people to judge the constancy of surface colors under different lights (color constancy) is less clear. This work had two aims: first, to quantify the degree of color constancy in subjects with congenital red-green color deficiency; second, to test whether the degree of color constancy in anomalous trichromats can be predicted from their Rayleigh anomaloscope matches. Methods. Color constancy of red-green color-deficient subjects was tested in a task requiring the discrimination of illuminant changes from surface-reflectance changes. Mondrian-like colored patterns, generated on the screen of a computer monitor, were used as stimuli to avoid the spatial cues provided by natural objects and scenes. Spectral reflectances were taken from the Munsell Book of Color and from natural scenes. Illuminants were taken from the daylight locus. Results. Protanopes and deuteranopes performed more poorly than normal trichromats with Munsell spectral reflectances but were less impaired with natural spectral reflectances. Protanomalous and deuteranomalous trichromats performed as well as, or almost as well as, normal trichromats, independent of the type of reflectance. Individual differences were not correlated with Rayleigh anomaloscope matches. Conclusions. Despite the evidence of clinical color-vision tests, red-green color-deficient persons are less disadvantaged than might be expected in their judgments of surface colors under different lights.
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Affiliation(s)
- Rigmor C Baraas
- Department of Optometry and Visual Science, Buskerud University College, Kongsberg, Norway.
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Cole BL, Lian KY, Lakkis C. Using clinical tests of colour vision to predict the ability of colour vision deficient patients to name surface colours. Ophthalmic Physiol Opt 2007; 27:381-8. [PMID: 17584289 DOI: 10.1111/j.1475-1313.2007.00493.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To determine the predictive power of commonly used tests for abnormal colour vision to identify patients who can or cannot name surface colours without error. METHODS The colour vision of 99 subjects with colour vision deficiency (CVD) was assessed using the Ishihara, the Richmond HRR (2002), the Farnsworth D15, the Medmont C100 and the Nagel anomaloscope. They named 10 surface colours (red, orange, brown, yellow, green, blue, purple, white, grey and black), which were presented in two shapes (lines and dots) and three sizes. The surface colours were also named by an age-matched group of 20 subjects with normal colour vision. The performance of the clinical tests to predict the CVD subjects who made no colour naming errors and those who made errors is expressed in terms of the predictive value of a pass P((P)) and the predictive value of a fail P((F)). RESULTS The P((P)) values of the tests were between 0.59 and 0.70 and P((F)) values were between 0.77 and 1.00. CONCLUSIONS A 'mild' classification with the Richmond HRR test, especially if no more than two errors are made on the HRR diagnostic plates, identifies patients with abnormal colour vision who are able to name surface colour codes without error or only the occasional error. A pass of the Farnsworth D15 test identifies patients who will make no or few (up to 6%) errors with a 10 colour code, but who will be able to name the colours of a seven colour code that does not include orange, brown and purple. If protans are excluded, the predictive value for a pass P((P)) for the Farnsworth D15 is improved from 0.59 to 0.70. The anomaloscope is not an especially good predictor of those who can recognise surface colour codes. However, an anomaloscope range >35 units identifies those who have difficulty in recognising surface colour codes, as does a fail at the Farnsworth D15 test.
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Affiliation(s)
- Barry L Cole
- Department of Optometry and Vision Sciences, University of Melbourne, Victoria, Australia.
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Foster DH, Amano K, Nascimento SMC. Color constancy in natural scenes explained by global image statistics. Vis Neurosci 2006; 23:341-9. [PMID: 16961965 PMCID: PMC1896061 DOI: 10.1017/s0952523806233455] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Accepted: 03/09/2006] [Indexed: 11/07/2022]
Abstract
To what extent do observers' judgments of surface color with natural scenes depend on global image statistics? To address this question, a psychophysical experiment was performed in which images of natural scenes under two successive daylights were presented on a computer-controlled high-resolution color monitor. Observers reported whether there was a change in reflectance of a test surface in the scene. The scenes were obtained with a hyperspectral imaging system and included variously trees, shrubs, grasses, ferns, flowers, rocks, and buildings. Discrimination performance, quantified on a scale of 0 to 1 with a color-constancy index, varied from 0.69 to 0.97 over 21 scenes and two illuminant changes, from a correlated color temperature of 25,000 K to 6700 K and from 4000 K to 6700 K. The best account of these effects was provided by receptor-based rather than colorimetric properties of the images. Thus, in a linear regression, 43% of the variance in constancy index was explained by the log of the mean relative deviation in spatial cone-excitation ratios evaluated globally across the two images of a scene. A further 20% was explained by including the mean chroma of the first image and its difference from that of the second image and a further 7% by the mean difference in hue. Together, all four global color properties accounted for 70% of the variance and provided a good fit to the effects of scene and of illuminant change on color constancy, and, additionally, of changing test-surface position. By contrast, a spatial-frequency analysis of the images showed that the gradient of the luminance amplitude spectrum accounted for only 5% of the variance.
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Affiliation(s)
- David H Foster
- Sensing, Imaging, and Signal Processing Group, School of Electrical and Electronic Engineering, University of Manchester, Manchester, United Kingdom.
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