Processing of color signals in female carriers of color vision deficiency

Konstantakopoulou, Evgenia; Rodriguez‐Carmona, Marisa; Barbur, John L.

doi:10.1167/12.2.11

Cited by 18 publications

(10 citation statements)

References 43 publications

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“…Color vision was examined with a low vision version of the Color Assessment and Diagnosis (CAD-LV) test (City Occupational Ltd., London, UK). The CAD test has been used to examine both congenital 37 and acquired color vision deficiencies, 38 , 39 and is validated with a reported high test-retest reliability. 40 To ascertain the degree of noncongenital deficiencies and elucidate if it was receptoral or postreceptoral in origin, some participants were invited to do the Cambridge Color Test (CCT; Cambridge Research Systems Ltd., Cambridge, UK), and anomaloscope (HMC Oculus Anomaloscope MR, Type 47700; Oculus Optikgeräte GmbH, Wetzlar, Germany).…”

Section: Methodsmentioning

confidence: 99%

Color Vision in Aniridia

Pedersen

Hagen

Landsend

et al. 2018

Invest. Ophthalmol. Vis. Sci.

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PurposeTo assess color vision and its association with retinal structure in persons with congenital aniridia.MethodsWe included 36 persons with congenital aniridia (10–66 years), and 52 healthy, normal trichromatic controls (10–74 years) in the study. Color vision was assessed with Hardy-Rand-Rittler (HRR) pseudo-isochromatic plates (4th ed., 2002); Cambridge Color Test and a low-vision version of the Color Assessment and Diagnosis test (CAD-LV). Cone-opsin genes were analyzed to confirm normal versus congenital color vision deficiencies. Visual acuity and ocular media opacities were assessed. The central 30° of both eyes were imaged with the Heidelberg Spectralis OCT2 to grade the severity of foveal hypoplasia (FH, normal to complete: 0–4).ResultsFive participants with aniridia had cone opsin genes conferring deutan color vision deficiency and were excluded from further analysis. Of the 31 with aniridia and normal opsin genes, 11 made two or more red-green (RG) errors on HRR, four of whom also made yellow-blue (YB) errors; one made YB errors only. A total of 19 participants had higher CAD-LV RG thresholds, of which eight also had higher CAD-LV YB thresholds, than normal controls. In aniridia, the thresholds were higher along the RG than the YB axis, and those with a complete FH had significantly higher RG thresholds than those with mild FH (P = 0.038). Additional increase in YB threshold was associated with secondary ocular pathology.ConclusionsArrested foveal formation and associated alterations in retinal processing are likely to be the primary reason for impaired red-green color vision in aniridia.

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Section: Methodsmentioning

confidence: 99%

Color Vision in Aniridia

Pedersen

Hagen

Landsend

et al. 2018

Invest. Ophthalmol. Vis. Sci.

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“…Verriest [48] argued that carriers exhibited higher error scores than normal trichromats, but he tested at 100 lx, which is considerably lower than that in the present study (at nearly 1000 lx). It is possible that some carriers' color vision might be more compromised under lower light levels [20]. This might explain the discrepancy in the literature as to whether or not carriers perform worse than normal trichromats on the FM100-Hue test [6][7][8]48].…”

Section: A Color Discrimination (Fm100-hue and Cct)mentioning

confidence: 99%

“…[47], [64], [67], [70], and [71]; for an exception, see Ref. [20]). Thus, little is known about how they would fare in comparison with those who make no errors.…”

Section: Why Do Deutan Carriers and Some Normal Females Show Poor mentioning

confidence: 99%

Performance of normal females and carriers of color-vision deficiencies on standard color-vision tests

Dees

Baraas

2014

J. Opt. Soc. Am. A

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Carriers of red-green color-vision deficiencies are generally thought to behave like normal trichromats, although it is known that they may make errors on Ishihara plates. The aim here was to compare the performance of carriers with that of normal females on seven standard color-vision tests, including Ishihara plates. One hundred and twenty-six normal females, 14 protan carriers, and 29 deutan carriers aged 9-66 years were included in the study. Generally, deutan carriers performed worse than protan carriers and normal females on six out of the seven tests. The difference in performance between carriers and normal females was independent of age, but the proportion of carriers that made errors on pseudo-isochromatic tests increased with age. It was the youngest carriers, however, who made the most errors. There was considerable variation in performance among individuals in each group of females. The results are discussed in relation to variability in the number of different L-cone pigments.

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“…Since our model predicts that extreme L cone fractions lead to larger f matching-range values, female carriers of dichromacy should have on average a larger f matching-range value. This may explain the observation that such carriers have on average an f matching-range that are about 2–3 times of that for non-carrier normal trichromats[19], though this difference in f matching-range has not been observed in other studies[26]. Regardless, our analysis above also leads to prediction (3) that a larger f matching-range is more likely to occur in a deutan than a protan carrier.…”

Section: Summary and Discussionmentioning

confidence: 50%

“…This is because typically n L > n M in normal non-carriers, hence, given each p value,

n_{L}^{'} (protan carrier) = p n_{L} > 1 - n_{L}^{'} (deutan carrier) = p n_{M} .

This means, the distance of

n_{L}^{'}

(protan carrier) from the extreme 0 is larger than the distance of

n_{L}^{'}

(deutan carrier) from the extreme 1, i.e., extreme L cone fractions are more likely in deutan than protan carriers. Predictions (2) and (3) regarding the f matching-range in female carriers must be tested using sufficiently large (larger than those from the observations so far[19, 26]) pools of female carriers for whom the spectral sensitivity of their underlying pigments is known and for whom the relative ratio of L:M cones is known. New imaging techniques may allow for L:M ratio to be estimated more expeditiously in these subjects[27].…”

Section: Summary and Discussionmentioning

confidence: 99%

An analytical model of the influence of cone sensitivity and numerosity on the Rayleigh match

Carroll

2016

J. Opt. Soc. Am. A

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The Rayleigh match is defined by the range of mixtures of red and green lights that appear the same as an intensity-adjustable monochromatic yellow light. The perceptual match indicates that the red/green mixture and the yellow light have evoked the same respective cone absorptions in the L- and M-cone pathways. Going beyond the existing models (e.g., Pokorny et al 1973, He & Shevell, 1995; Thomas & Mollon, 2004; Barbur et al 2008), the Poisson noise in cone absorptions is proposed to make the matching proportion of red-green mixtures span a finite range, since any mixture in that range evokes cone absorptions that do not differ from those by a yellow light by more than the variations in the absorption noise. We derive a mathematical formula linking the match midpoint or match range with the sensitivities and numerosities of the two cones. The noise-free, exact, matching point, close to the mid-point of the matching range, depends only on the L- and M-cone sensitivities to each of the red, green, and yellow lights (these sensitivities in turn depend on the preferred wavelengths (λmax) and optical densities of the cone pigments and the various pre-receptor retinal light filtering properties). Meanwhile, the matching range depends on both these cone sensitivities and the relative numerosity of the L- and M-cones. The model predicts that, in normal trichromats, all other things being equal, the match range is smallest when the ratio r between L and M cone densities is r = R−1/2 with R as the ratio between the sensitivities of the L and M cones to the yellow light, i.e., when L and M cones are similarly abundant in typical cases, and as r departs from R−1/2 the match range increases. For example, when one cone type is 10 times more numerous, the match range increases 2-3 fold, depending on the sensitivities of the cones. Testing these model predictions requires either a large data set to identify the effect of one factor (e.g., cone numerosity) while averaging out the effects of the other factors (e.g., cone sensitivities), or for all factors to be known. A corollary of this prediction is that, because they are more likely than usual to have very different L and M cone densities, the matching ranges of normal female trichromats who are carriers of dichromacy (but not anomalous trichromacy) are likely to have a larger matching range than usual, particularly for the deutan carriers. In addition, the model predicts that in strong tetrachromats (whose four dimensions of color are preserved post-receptorally), the Rayleigh matching is either impossible or the matching range is typically smaller than usual.

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Processing of color signals in female carriers of color vision deficiency

Cited by 18 publications

References 43 publications

Color Vision in Aniridia

Color Vision in Aniridia

Performance of normal females and carriers of color-vision deficiencies on standard color-vision tests

An analytical model of the influence of cone sensitivity and numerosity on the Rayleigh match

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