Discrimination thresholds of normal and anomalous trichromats: Model of senescent changes in ocular media density on the Cambridge Colour Test

Shinomori, Keizo; Panorgias, Athanasios; Werner, John S.

doi:10.1364/josaa.33.000a65

Cited by 15 publications

(12 citation statements)

References 40 publications

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“…The study only included Caucasians, and from an age range that did not include anyone older than 70 (healthy controls) and 78 (early AMD) years old, potentially limiting the generalizability of our results. Despite this limitation, the observed continuous age-related decline in L-cone acuity from young adulthood is the same as that observed for other measures of chromatic sensitivity ( Knoblauch et al, 2001 ; Dees et al, 2015 ; Shinomori et al, 2016 ). Furthermore, the inclusion of the more elderly low-risk AMD participants helps to emphasize the differences from those with the more severe form of early AMD.…”

Section: Discussionsupporting

confidence: 68%

“…There is one report of shortening of cone outer and inner segments in healthy aging ( Elsner et al, 2020 ), as well as a reported decline in mitochondrial membrane potential and cellular energy in cone IS ( Eells, 2019 ). In parallel, it is well known that there is a senescent decline, that begins in young adulthood, in spatio-chromatic contrast sensitivity ( Dees et al, 2015 ) and other measures of chromatic sensitivity ( Knoblauch et al, 2001 ; Shinomori et al, 2016 ). Furthermore, L-cone isolating (spatio-chromatic) acuity has been reported to correlate with cone density ( Baraas et al, 2017 ).…”

Section: Introductionmentioning

confidence: 99%

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The Relationship Between Perifoveal L-Cone Isolating Visual Acuity and Cone Photoreceptor Spacing—Understanding the Transition Between Healthy Aging and Early AMD

Baraas

Horjen

Gilson

et al. 2021

Front. Aging Neurosci.

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Background: Age-related macular degeneration (AMD) is a multifactorial degenerative disorder that can lead to irreversible loss of visual function, with aging being the prime risk factor. However, knowledge about the transition between healthy aging and early AMD is limited. We aimed to examine the relationship between psychophysical measures of perifoveal L-cone acuity and cone photoreceptor structure in healthy aging and early AMD.Methods and Results: Thirty-nine healthy participants, 10 with early AMD and 29 healthy controls were included in the study. Multimodal high-resolution retinal images were obtained with adaptive-optics scanning-light ophthalmoscopy (AOSLO), optical-coherence tomography (OCT), and color fundus photographs. At 5 degrees retinal eccentricity, perifoveal L-cone isolating letter acuity was measured with psychophysics, cone inner segment and outer segment lengths were measured using OCT, while cone density, spacing, and mosaic regularity were measured using AOSLO. The Nyquist sampling limit of cone mosaic (Nc) was calculated for each participant. Both L-cone acuity and photoreceptor inner segment length declined with age, but there was no association between cone density nor outer segment length and age. A multiple regression showed that 56% of the variation in log L-cone acuity was accounted for by Nc when age was taken into account. Six AMD participants with low risk of progression were well within confidence limits, while two with medium-to-severe risk of progression were outliers. The observable difference in cone structure between healthy aging and early AMD was a significant shortening of cone outer segments.Conclusion: The results underscore the resilience of cone structure with age, with perifoveal functional changes preceding detectable changes in the cone photoreceptor mosaic. L-cone acuity is a sensitive measure for assessing age-related decline in this region. The transition between healthy aging of cone structures and changes in cone structures secondary to early AMD relates to outer segment shortening.

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Section: Discussionsupporting

confidence: 68%

Section: Introductionmentioning

confidence: 99%

The Relationship Between Perifoveal L-Cone Isolating Visual Acuity and Cone Photoreceptor Spacing—Understanding the Transition Between Healthy Aging and Early AMD

Baraas

Horjen

Gilson

et al. 2021

Front. Aging Neurosci.

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“…However, the study only focused on young people with a normal color vision system. The color constancy of old people and color deficient people under RGB‐LED light sources was not investigated herein because the color vision of old people is affected by complex aging effects related to the S‐cone and that of color deficient people is affected by the lack or mutation of the L‐ or M‐cone . However, the investigation on color constancy of these 2 groups of people under RGB‐LED light sources is useful and should be investigated in the future.…”

Section: Discussionmentioning

confidence: 99%

Categorical color constancy under RGB‐LED light sources

Liao

Yan

et al. 2018

Color Research & Application

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The light-emitting diode (LED)-based light sources have been widely applied across numerous industries and in everyday practical uses. Recently, the LED-based light source consisting of red, green and blue LEDs with narrow spectral bands (RGB-LED) has been a more preferred illumination source than the common white phosphor LED and other traditional broadband light sources because the RGB-LED can create many types of illumination color. The color rendering index of the RGB-LED, however, is considerably lower compared to the traditional broadband light sources and the multi-band LED light source (MB-LED), which is composed of several LEDs and can accurately simulate daylight illuminants. Considering 3 relatively narrow spectral bands of the RGB-LED light source, the color constancy, which is referred to as the ability of the human visual system to attenuate influences of illumination color change and hold the perception of a surface color constant, may be worse under the RGB-LED light source than under the traditional broadband light sources or under the MB-LED. In this study, we investigated categorical color constancy using a color naming method with real Munsell color chips under illumination changes from neutral to red, green, blue, and yellow illuminations. The neutral and 4 chromatic illuminants were produced by the RGB-LED light source. A modified use of the color constancy index, which describes a centroid shift of each color category, was introduced to evaluate the color constancy performance. The results revealed that categorical color constancy under the 4 chromatic illuminants held relatively well, except for the red, brown, orange, and yellow color categories under the blue illumination and the orange color category under the yellow illumination. Furthermore, the categorical color constancy under red and green illuminations was better than the categorical color constancy under blue and yellow illuminations. The results indicate that a color constancy mechanism in the visual system functions in color categories when the illuminant emits an insufficient spectrum to render the colors of reflecting surfaces accurately. However, it is not recommended to use the RGB-LED light source to produce blue and yellow illuminations because of the poor color constancy.

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“…Normative values for JNDs measured with the CCT are available in terms of different age groups [20][21][22] or different color-vision abilities [23,24]. However, these normative results generally represent data measured close to the neutral reference point that compares different groups of subjects.…”

Section: Introductionmentioning

confidence: 99%

Chromatic Discrimination Thresholds as a Function of Color Differences and Cone Excitations

Urbin

Nagy

2021

Period. Polytech. Mech. Eng.

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In this paper, Just Noticeable Differences (JNDs) of color-normal subjects measured towards the Protan, Deutan, and Tritan confusion points are presented as a function of the chromaticity of the reference points. Measurements were executed with the Cambridge Colour Test Trivector test in equidistant reference points towards eight directions equally spaced and centered on the neutral reference point in the CIE 1976 UCS diagram.Results were evaluated as the function of the distance between the reference points and the neutral point. The reference points were the chromaticities of the backgrounds of the pseudoisochromatic plates in the test, and the neutral point was defined as equal energy white. The evaluation was performed considering ∆Eu'v' differences and L/(L + M) and S/(L + M) ratios of the cone-excitations.Chromatic discrimination thresholds exceeded the normative upper limit of color normal subjects in ∆Eu'v' units at extreme reference points. Shifting the reference points from the neutral point towards the confusion points indicated an increase of Just Noticeable Differences measured towards the confusion points following second-order polynomials. Based on our results a model estimating the JNDs expressed in ∆Eu'v' units towards the confusion points was recommended.Even though CIE 1976 UCS diagram is not a perceptually uniform color space, the Just Noticeable Differences measured with the CCT correlate with the corresponding L' and S' cone excitations. This confirms the basic applicability of the CIE 1976 UCS diagram for characterizing Just Noticeable Differences. For complete perceptual analysis, the use of cone-excitation-based metrics is still essential and recommended.

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Discrimination thresholds of normal and anomalous trichromats: Model of senescent changes in ocular media density on the Cambridge Colour Test

Cited by 15 publications

References 40 publications

The Relationship Between Perifoveal L-Cone Isolating Visual Acuity and Cone Photoreceptor Spacing—Understanding the Transition Between Healthy Aging and Early AMD

The Relationship Between Perifoveal L-Cone Isolating Visual Acuity and Cone Photoreceptor Spacing—Understanding the Transition Between Healthy Aging and Early AMD

Categorical color constancy under RGB‐LED light sources

Chromatic Discrimination Thresholds as a Function of Color Differences and Cone Excitations

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