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Somers LP, Franklin A, Bosten JM. Empirical tests of the effectiveness of EnChroma multi-notch filters for enhancing color vision in deuteranomaly. Vision Res 2024; 218:108390. [PMID: 38531192 DOI: 10.1016/j.visres.2024.108390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 03/11/2024] [Accepted: 03/16/2024] [Indexed: 03/28/2024]
Abstract
Manufacturers of notch filter-based aids for color vision claim that their products can enhance color perception for people with anomalous trichromacy, a form of color vision deficiency (CVD). Anecdotal reports imply that people with CVD can have radically enhanced color vision when using the filters. However, existing empirical research largely focussed on the effect of notch filters on performance on diagnostic tests for CVD has not found that they have any substantial effect. Informed by a model of anomalous trichromatic color vision, we selected stimuli predicted to reveal the effects of EnChroma filters. Using these stimuli, we tested the ability of EnChroma filters to enhance color vision for 10 deuteranomalous trichromats in three experiments: 1. asymmetric color matching between test and control filter conditions, 2. color discrimination measured using four alternative forced-choice, and 3. color appearance measured using dissimilarity ratings to reconstruct subjective color spaces using multidimensional scaling. To investigate potential effects of long-term adaptation or perceptual learning, participants completed all three experiments at two time points, on first exposure to the filters, and after a week of regular use. We found a significant effect of the filters on color matches in the direction predicted by the model at both time points, implying that the filters can enhance the anomalous trichromatic color gamut. However, we found minimal effect of the filters on color discrimination at threshold. We found a significant effect of the filters in enhancing the appearance of colors along the red-green axis at the first time point, and a trend in the same direction at the second time point. Our results provide the first quantitative experimental evidence that notch filters can enhance color perception for anomalous trichromats.
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Affiliation(s)
- Lucy P Somers
- Sussex Vision Lab, School of Psychology, University of Sussex, Falmer, UK
| | - Anna Franklin
- Sussex Baby Lab and Sussex Colour Group, School of Psychology, University of Sussex, Falmer, UK
| | - Jenny M Bosten
- Sussex Vision Lab, School of Psychology, University of Sussex, Falmer, UK.
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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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EMERY KARAJ, ISHERWOOD ZOEYJ, WEBSTER MICHAELA. Gaining the system: limits to compensating color deficiencies through post-receptoral gain changes. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2023; 40:A16-A25. [PMID: 37132998 PMCID: PMC10157001 DOI: 10.1364/josaa.480035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 12/14/2022] [Indexed: 05/04/2023]
Abstract
Color percepts of anomalous trichromats are often more similar to normal trichromats than predicted from their receptor spectral sensitivities, suggesting that post-receptoral mechanisms can compensate for chromatic losses. The basis for these adjustments and the extent to which they could discount the deficiency are poorly understood. We modeled the patterns of compensation that might result from increasing the gains in post-receptoral neurons to offset their weakened inputs. Individual neurons and the population responses jointly encode luminance and chromatic signals. As a result, they cannot independently adjust for a change in the chromatic inputs, predicting only partial recovery of the chromatic responses and increased responses to achromatic contrast. These analyses constrain the potential sites and mechanisms of compensation for a color loss and characterize the utility and limits of neural gain changes for calibrating color vision.
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Affiliation(s)
- KARA J. EMERY
- Department of Psychology and Graduate Program in Integrative Neuroscience, University of Nevada, Reno, Reno NV 89557
- Center for Data Science, New York University, New York NY 10011
| | - ZOEY J. ISHERWOOD
- Department of Psychology and Graduate Program in Integrative Neuroscience, University of Nevada, Reno, Reno NV 89557
| | - MICHAEL A. WEBSTER
- Department of Psychology and Graduate Program in Integrative Neuroscience, University of Nevada, Reno, Reno NV 89557
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Bosten JM, Coen-Cagli R, Franklin A, Solomon SG, Webster MA. Special issue: Calibrating the visual system. Vision Res 2022; 201:108132. [PMID: 36279610 DOI: 10.1016/j.visres.2022.108132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jenny M Bosten
- School of Psychology, University of Sussex, Brighton, United Kingdom
| | - Ruben Coen-Cagli
- Department of Systems and Computational Biology and Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Anna Franklin
- School of Psychology, University of Sussex, Brighton, United Kingdom
| | - Samuel G Solomon
- Department of Experimental Psychology, University College London, London, United Kingdom
| | - Michael A Webster
- Department of Psychology and Graduate Program in Integrative Neuroscience, University of Nevada, Reno, Reno NV, USA.
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Bosten JM, Coen-Cagli R, Franklin A, Solomon SG, Webster MA. Calibrating Vision: Concepts and Questions. Vision Res 2022; 201:108131. [PMID: 37139435 PMCID: PMC10151026 DOI: 10.1016/j.visres.2022.108131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The idea that visual coding and perception are shaped by experience and adjust to changes in the environment or the observer is universally recognized as a cornerstone of visual processing, yet the functions and processes mediating these calibrations remain in many ways poorly understood. In this article we review a number of facets and issues surrounding the general notion of calibration, with a focus on plasticity within the encoding and representational stages of visual processing. These include how many types of calibrations there are - and how we decide; how plasticity for encoding is intertwined with other principles of sensory coding; how it is instantiated at the level of the dynamic networks mediating vision; how it varies with development or between individuals; and the factors that may limit the form or degree of the adjustments. Our goal is to give a small glimpse of an enormous and fundamental dimension of vision, and to point to some of the unresolved questions in our understanding of how and why ongoing calibrations are a pervasive and essential element of vision.
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Affiliation(s)
| | - Ruben Coen-Cagli
- Department of Systems Computational Biology, and Dominick P. Purpura Department of Neuroscience, and Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx NY
| | | | - Samuel G Solomon
- Institute of Behavioural Neuroscience, Department of Experimental Psychology, University College London, UK
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Abstract
In our tendency to discuss the objective properties of the external world, we may fail to notice that our subjective perceptions of those properties differ between individuals. Variability at all levels of the color vision system creates diversity in color perception, from discrimination to color matching, appearance, and subjective experience, such that each of us lives in a unique perceptual world. In this review, I discuss what is known about individual differences in color perception and its determinants, particularly considering genetically mediated variability in cone photopigments and the paradoxical effects of visual environments in both contributing to and counteracting individual differences. I make the case that, as well as being of interest in their own right and crucial for a complete account of color vision, individual differences can be used as a methodological tool in color science for the insights that they offer about the underlying mechanisms of perception. Expected final online publication date for the Annual Review of Vision Science, Volume 8 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Jenny M Bosten
- School of Psychology, University of Sussex, Brighton, United Kingdom;
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Emery KJ, Kuppuswamy Parthasarathy M, Joyce DS, Webster MA. Color perception and compensation in color deficiencies assessed with hue scaling. Vision Res 2021; 183:1-15. [PMID: 33636681 DOI: 10.1016/j.visres.2021.01.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 12/07/2020] [Accepted: 01/14/2021] [Indexed: 12/20/2022]
Abstract
Anomalous trichromats have three classes of cone receptors but with smaller separation in the spectral sensitivities of their longer-wave (L or M) cones compared to normal trichromats. As a result, the differences in the responses of the longer-wave cones are smaller, resulting in a weaker input to opponent mechanisms that compare the LvsM responses. Despite this, previous studies have found that their color percepts are more similar to normal trichromats than the smaller LvsM differences predict, suggesting that post-receptoral processes might amplify their responses to compensate for the weaker opponent inputs. We evaluated the degree and form of compensation using a hue-scaling task, in which the appearance of different hues is described by the perceived proportions of red-green or blue-yellow primary colors. The scaling functions were modeled to estimate the relative salience of the red-green to blue-yellow components. The red-green amplitudes of the 10 anomalous observers were 1.5 times weaker than for a group of 26 normal controls. However, their relative sensitivity at threshold for detecting LvsM chromatic contrast was on average 6 times higher, consistent with a 4-fold gain in the suprathreshold hue-scaling responses. Within-observer variability in the settings was similar for the two groups, suggesting that the suprathreshold gain did not similarly amplify the noise, at least for the dimension of hue. While the compensation was pronounced it was nevertheless partial, and anomalous observers differed systematically from the controls in the shapes of the hue-scaling functions and the corresponding loci of their color categories. Factor analyses further revealed different patterns of individual differences between the groups. We discuss the implications of these results for understanding both the processes of compensation for a color deficiency and the limits of these processes.
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Affiliation(s)
- Kara J Emery
- Graduate Program in Integrative Neuroscience and Department of Psychology, University of Nevada, Reno, Reno, NV 89557, United States
| | - Mohana Kuppuswamy Parthasarathy
- Graduate Program in Integrative Neuroscience and Department of Psychology, University of Nevada, Reno, Reno, NV 89557, United States
| | - Daniel S Joyce
- Graduate Program in Integrative Neuroscience and Department of Psychology, University of Nevada, Reno, Reno, NV 89557, United States
| | - Michael A Webster
- Graduate Program in Integrative Neuroscience and Department of Psychology, University of Nevada, Reno, Reno, NV 89557, United States.
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