Nonlinear cortical encoding of color predicts enhanced McCollough effects in anomalous trichromats

Robinson, Alan; Bosten, Jenny; MacLeod, Donald I. A.

doi:10.1016/j.visres.2022.108153

Cited by 5 publications

(2 citation statements)

References 66 publications

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“…Another stimulus consideration lies in the saturations of the to-be-discriminated colors. There is evidence that the contrast response functions of anomalous trichromats are steeper than those of normal trichromats at high (physical) red-green contrasts (Knoblauch et al, 2020;Boehm et al, 2021;Robinson et al, 2023). It is therefore possible that discrimination thresholds for saturated colors may be better facilitated by EnChroma filters than at the white point where we measured discrimination thresholds.…”

Section: Discussionmentioning

confidence: 92%

Empirical tests of the effectiveness of EnChroma multi-notch filters for enhancing color vision in anomalous trichromacy

Bosten¹,

Franklin²,

Somers³

2023

Preprint

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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 an effect of EnChroma filters. Using these stimuli, we tested the ability of EnChroma filters to enhance color vision for 10 anomalous 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. We found a significant effect of the filters in enhancing the appearance of colors along the red-green axis, but only at the first time point, and not after a week of regular use. Our results provide the first good evidence that notch filters can enhance color perception for anomalous trichromats.

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Section: Discussionmentioning

confidence: 92%

Empirical tests of the effectiveness of EnChroma multi-notch filters for enhancing color vision in anomalous trichromacy

Bosten¹,

Franklin²,

Somers³

2023

Preprint

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“…In particular, anomalous trichromats are thought to show 'postreceptoral compensation' of their impaired retinal L/(L+M) color signals (Regan & Mollon, 1997;Boehm et al, 2014), where representations of anomalous trichromats' equivalents of L/(L+M) color differences are thought to be expanded in the cortex so that the range of contrasts may appear roughly the same for anomalous trichromats as for normal trichromats (Boehm et al, 2014;Tregillus et al, 2021). Although postreceptoral compensation may be incomplete (Emery et al, 2023;Robinson et al, 2023), and there may be individual differences in its extent (Boehm et al, 2021), it may limit the extent to which EnChroma glasses can have an effect on color appearance. The model requires validation from behavioral experiments to determine whether the predicted changes in saturation as represented in the cone-opponent mechanisms lead to equivalent changes in perceived saturation.…”

Section: Discussionmentioning

confidence: 99%

Predicted effectiveness of EnChroma multi-notch filters for enhancing color perception in anomalous trichromats

Bosten,

Somers

2023

Preprint

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EnChroma filters are aids designed to improve color vision for anomalous trichromats. However, their use is controversial, because the results of lab-based assessments of their effectiveness have so far largely failed to agree with positive anecdotal reports. However, the effectiveness of EnChroma filters will vary depending on the conditions of viewing, including whether the stimuli are broadband reflective surfaces or colors presented on RGB displays, whether illumination spectra are broadband or narrowband, the transmission spectra of particular filters, and the cone spectral sensitivity functions of the observer. We created a model of anomalous trichromatic color vision to predict the effects of EnChroma filters on red-green color vision. Using the model we varied illumination, filter model and observer cone sensitivity functions, and tested the effect of presenting colors as broadband reflective surfaces or on RGB displays. We also used hyperspectral images to assess the impact of the filters on red-green color vision for natural scenes. Model results predicted that the filters are broadly effective at enhancing red-green contrasts under a range of viewing conditions, but are substantially more effective for deuteranomals than for protanomals. They are predicted to be more effective for broadband reflective surfaces presented under broadband illuminants than for surfaces presented under narrowband illuminants or for colors presented on RGB displays. Since the potential impacts of contrast adaptation and perceptual learning are not considered in the model, itneeds validating empirically. Results of empirical tests of the effects of EnChroma filters on deuteranomalous color vision in comparison with model predictions are presented in an accompanying paper (Somers et al., in prep.).

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Predicted effectiveness of EnChroma multi-notch filters for enhancing color perception in anomalous trichromats

Somers,

Bosten

2024

Vision Research

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Nonlinear cortical encoding of color predicts enhanced McCollough effects in anomalous trichromats

Cited by 5 publications

References 66 publications

Empirical tests of the effectiveness of EnChroma multi-notch filters for enhancing color vision in anomalous trichromacy

Empirical tests of the effectiveness of EnChroma multi-notch filters for enhancing color vision in anomalous trichromacy

Predicted effectiveness of EnChroma multi-notch filters for enhancing color perception in anomalous trichromats

Predicted effectiveness of EnChroma multi-notch filters for enhancing color perception in anomalous trichromats

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