Luminosity thresholds of colored surfaces are determined by their upper-limit luminances empirically internalized in the visual system

We typically have a fairly good idea whether a given object is self-luminous or illuminated, but it is not fully understood how we make this judgment. This study aimed to identify determinants of the luminosity threshold, a luminance level at which a surface begins to appear self-luminous. We specifically tested a hypothesis that our visual system knows the maximum luminance level that a surface can reach under the physical constraint that a surface cannot reflect more light than any incident light and applies this prior to determine the luminosity thresholds. Observers were presented with a 2-degree circular test field surrounded by numerous overlapping colored circles and luminosity thresholds were measured as a function of (i) the chromaticity of the test field, (ii) the shape of surrounding color distribution, and (iii) the color of the illuminant of the surrounding colors. We found that the luminosity thresholds peaked around the chromaticity of test illuminants and decreased as the purity of the test chromaticity increased. However, the loci of luminosity thresholds across chromaticities were nearly invariant to the shape of the surrounding color distribution and generally resembled the loci drawn from theoretical upper-limit luminances and upper-limit luminance boundaries of real objects. These trends were particularly evident for illuminants on the black-body locus and did not hold well under atypical illuminants, such as magenta or green. These results support the idea that our visual system empirically internalizes the gamut of surface colors under natural illuminants and a given object appears self-luminous when its luminance exceeds this internalized upper-limit luminance.     

高度近视眼不同后巩膜形态黄斑中心凹分布研究

目的：研究高度近视眼黄斑中心凹在不同后巩膜形态的分布。

方法：收集2016-05/2018-02南昌大学第三附属医院高度近视患者126例207眼,按照Curtin的后巩膜形态分类方法分为三组：A组为Ⅰ和Ⅱ型后巩膜形态眼,B组为Ⅲ型后巩膜形态眼,C组为Ⅶ、Ⅸ、Ⅹ型后巩膜形态眼。将眼底后极部区域分为1、2、3区域。测量中心凹至通过视盘中心垂直线的水平距离(HDFCO)、中心凹至通过视盘中心水平线的垂直距离(VDFCO)和视力。研究在高度近视不同后巩膜形态中心凹位置的分布。

结果：在后极部1区,3眼(1.5%)均来自A组。在后极部2区,117眼(56.5%)来自A组,15眼(7.2%)来自B组,13眼(6.3%)来自C组。三组HDFCO分别为5 037±507、4 771±509、5 585±773μm(F=8.38,P<0.01)。三组VDFCO分别为615±297、643±322、504±363(F=0.87,P=0.41)。在后极部3区,43眼(20.7%)来自A组,7眼(3.4%)来自B组,9眼(4.4%)来自C组。三组HDFCO分别为5 048±683、4 444±540、5 293±840(F=3.13,P=0.05)。三组VDFCO分别为1 385±484、1 225±201、1 664±318μm(F=2.18, P=0.12)。中心凹位于2区和3区的高度近视眼平均最佳矫正视力(LogMAR)分别为4.87±0.22 和 4.77±0.27(t=-1.55,P=0.12)。

结论：高度近视眼黄斑中心凹位置在不同后巩膜形态中发生轻微变化,对最佳矫正视力无影响。     

百分制色觉定量检测表对正常人及先天性色觉异常者色觉感色力及辨色力的评估

目的 通过自行设计百分制色觉定量检测表(百分制量表)检查正常人及先天性色觉异常者色觉感色力和辨色力的差异。设计诊断技术评价。研究对象 采用俞自萍色盲本筛查色觉正常者48例(男性46例,女性2例);采用Farnsworth Munsell(FM-100)色相检测法确诊的红色觉异常者28例(男性27例,女性1例),绿色觉异常者71例(男性68例,女性3例)。方法 采用自制百分制量表检测受试者的色觉感色力和辨色力,并对评分进行对比分析,采用中位数(四分位数)描述。主要指标红色、绿色及蓝色感色力和红绿、红蓝及绿蓝辨色力百分制量表评分。结果 用百分制量表评价,正常人红色、绿色、蓝色感色力评分分别为96(95,97)、98(97,98)、95(92.25,96);红绿、红蓝、绿蓝辨色力评分分别为97(97,98)、96(95,97)、98(97,98)。与正常人相比,先天性红色觉异常患者的红色感色力[91.5(89.25,93)]、蓝色感色力[93(90,95)]和红蓝辨色力[90.50(86.25,92)]评分下降(Z=-6.837、-3.151、-6.780,P均<0.01);先天性绿色...     

色觉异常疾病的视觉电生理评价

色觉是视觉功能的一个基本而重要的组成部分,是人类视网膜锥体细胞的特殊感觉功能。一般先天性色盲多无自觉症状,通常在体检中进行常规色觉检查时被发现。继发性色觉障碍更需要及早明确原发疾病对色觉是否产生影响。色觉检查方法的特异性、敏感性及发现疾病早期特有的表现尤为重要。色觉检查的方法很多,但大多数属于主观检查法,包括假同色图测验、色相排列测验和色盲镜等;客观检查以视觉电生理检查为主,其中荧光素眼底血管造影（FFA）、视网膜密度检测、CT扫描等有助于明确视神经、视网膜及黄斑病变的形态学评估。临床视觉电生理检查属于客观的功能学检查方法,对于一些特殊人群色觉的评定及对某些继发性色觉改变的早期诊断显示了一定的优势。就临床电生理在继发性色觉障碍疾病中的特征性表现及早期诊断价值进行综述。     

Implications of inherited color vision deficiency on occupations: A neglected entity!

Purpose:To highlight the plight of individuals with congenital color vision deficiency (CVD).Methods:This is a retrospective study in which 191 electronic medical records of individuals with the diagnosis of inherited CVD, who visited the eye institute, between January 2010 and January 2021 were included. The inclusion criteria included diagnosis based on the failure in pseudoisochromatic plates (Ishihara / Hardy, Rand and Rittler (HRR) and age range between 18 and 35 years. The patient’s medical history, age, gender, type of defect, and preference for colored contact lenses was noted. Medical records were excluded if the participant had any other ocular pathology apart from congenital CVD.Results:At least 30% (57/191) of the individuals explicitly requested for color vision examination for a job-related purpose. Amongst them, the most common jobs aspired were army (~25%; [14/57]) followed by police (21%; [12/57]). There was only 2.6% (5/191) of individuals in which the type of CVD (protan/deutan) was classified. Only 5.2% of them (10/191) sought an X-Chrome contact lens trial.Conclusion:This study reported the occupational setbacks experienced by individuals with CVD. This study highlights the need to identify CVD at a younger age, thereby avoiding occupational-related setbacks later in life.     

Effects of retinal eccentricity on displacement thresholds for unidirectional and oscillatory stimuli

Motion sensitivity was determined for line stimuli undergoing unidirectional and oscillatory displacements at various retinal eccentricities. Oscillatory motions of short duration were found to produce consistently greater motion thresholds than unidirectional stimuli at each eccentricity tested. Increasing retinal eccentricity elevated motion thresholds similarly for both forms of stimulus motion. The observed differences between unidirectional and oscillatory stimuli are attributed to differences in the temporal summation of the two forms of stimuli at short duration. These findings also suggest that differences in motion sensitivity between central and peripheral vision are quantitative rather than qualitative.     

Luminance dependency of perceived color shift after color contrast adaptation caused by higher-order color channels

Color adaptation is a phenomenon in which, after prolonged exposure to a specific color (i.e. adaptation color), the perceived color shifts to approximately the opposite color direction of the adaptation color. Color adaptation is strongly related to sensitivity changes in photoreceptors, such as von Kries adaptation and cone-opponent mechanisms. On the other hand, the perceptual contrast of colors (e.g. perceptual saturation of the red-green direction) decreases after adaptation to a stimulus with spatial and/or temporal color modulation along the color direction. This phenomenon is referred to as color contrast adaptation. Color contrast adaptation has been used to investigate the representation of colors in the visual system. In the present study, we measured color perception after color contrast adaptation to stimuli with temporal color modulations along complicated color loci in a luminance-chromaticity plane. We found that, after the observers adapted to color modulations with different chromaticities at higher, medium, and lower luminance (e.g. temporal alternations among red, green, and red, each at a different luminance level), the chromaticity corresponding to perceptual achromaticity (the achromatic point) shifted to the same color direction as the adaptation chromaticity in each test stimulus luminance. In contrast, this luminance dependence of the achromatic point shift was not observed after adaptation to color modulations with more complex luminance-chromaticity correspondences (e.g. alternating red, green, red, green, and red, at five luminance levels, respectively). In addition, the occurrence or nonoccurrence of the luminance-dependent achromatic point shift was qualitatively predicted using a noncardinal model composed of channels preferring intermediate color directions between the cardinal chromaticity and luminance axes. These results suggest that the noncardinal channels are involved in the luminance-dependent perceived color shift after adaptation.     

Infant color vision: infants' spontaneous color preferences are well behaved

Stochastic transitivity (ST) is a property of preferences among pairs of objects formed from three alternatives, a, b, and c. In general, ST states that if a is preferred to b, and b is preferred to c, then a will be preferred to c. Stochastic transitivity can be weak, moderate, strong or strict (see text). In the present paper, we analyse the presence and degree of ST in the data from two experiments concerning 12-week-old infants' spontaneous color preferences. In the first experiment (Triads), we tested five sets of three stimuli in pairs of two (a vs. b, b vs. c, a vs. c). In each case two stimuli were chromatic and one was White. Strict ST was seen in all cases. In Experiment 2 (Complementaries), we tested White against pairs of stimuli from opposite sides of the White point (red vs. blue-green, blue vs. yellow, and green vs. purple). The purities required for equal (50/50) preference between the two chromatic stimuli were consistent with the preferences for each of the two stimuli over White. In addition, 12 new triads were generated from the Complementaries experiment. Strict ST was seen in six out of 12 cases, and Moderate ST was seen in the other six. As discussed further in the accompanying paper [Zemach, I. K., Chang, S., & Teller, D. Y. (2007). Infant color vision: prediction of infants' spontaneous color preferences], White was the least preferred stimulus in every triad tested. Although more extensive studies are needed, the data suggest that infants' hue preferences are reasonably well behaved across different choices of stimulus pairs.     

Human color constancy based on the geometry of color distributions

The physical inputs to our visual system are dictated by the interplay between lights and surfaces; thus, for surface color to be stably perceived, the influence of the illuminant must be discounted. To reveal our strategy to infer the illuminant color, we conducted three psychophysical experiments designed to test our optimal color hypothesis that we internalize the physical color gamut under various illuminants and apply the prior to estimate the illuminant color. In each experiment, we presented 61 hexagons arranged without spatial gaps, where the surrounding 60 hexagons were set to have a specific shape in their color distribution. We asked participants to adjust the color of a center test field so that it appeared to be a full-white surface placed under a test illuminant. Results and computational modeling suggested that, although our proposed model is limited in accounting for estimation of illuminant intensity by human observers, it agrees fairly well with the estimates of illuminant chromaticity in most tested conditions. The accuracy of estimation generally outperformed other tested conventional color constancy models. These results support the hypothesis that our visual system can utilize the geometry of scene color distribution to achieve color constancy.     

Color mixture thresholds measured on a color television — a new method for analysis,classification and diagnosis of neuro-ophthalmic disease

A color television display can be used to determine color and brightness discrimination thresholds using identical adaptation conditions and experimental technique. The color discrimination threshold is measured by using an equiluminous test spot - i.e. one which differs in color from the surrounding screen but has the same luminance. Because there is no brightness clue, the subject is forced to detect such a spot by using color discrimination. It is shown how color and brightness thresholds may be determined from threshold measurements of different color-mixtures even though it is not known beforehand which stimulus will be equiluminous for the subject. Results are shown for normal subjects, congenital color defectives and for two patients having optic nerve disease who show respectively non-selective and selective loss of color discrimination compared to brightness discrimination. Normal control data are presented, illustrating the effect of eccentricity, optical blur, viewing distance, pupil size and age. It is concluded that the technique is relatively insensitive to moderate variations in these factors and that it is more sensitive in detecting selective color loss than a spectral sensitivity technique which has been described previously.     

一种新的计算机适应色觉试验

目的:提出一种新的计算机适应色觉试验(NCACVT)并且解释它在实际应用中的可靠性和重要性.方法:法一孟二式100色度试验(FM100HT)和Holmgren试验已经被改良并且适应计算机应用.经典的Ishihara假同色法试验方法(IPPT)已被假定是色盲的一个简便的筛选检查工具;因此依照Ishihara试验结果,受试者被分为色觉有缺陷组(第1组)和对照组(第2组).第1组为色觉有缺陷者13例(男12例,女1例),年龄在19～29(平均21)岁,而第2组为对照组,13个受试者色觉无缺陷(男8例,女5例),年龄在19～28(平均22)岁.为了研究两组人的色觉敏感性,所有的受试者都要进行FM100HT和NCACVT试验.将经典的IPPT,FM100HT和NCACVT的试验结果用统计学方法进行比较.在这两组中NCACVT和FM100HT的误差计分用秩和检验来分析.结果:在误差计分中的差别分别在统计学上是有显著意义的(U=169,P＜0.05;U=153 P＜0.05).根据NCACVT来诊断色觉缺陷的临界点是通过使用接受机器作特征曲线(ROC)而被发现是23.根据23这个临界点的误差计分,在筛选检查色觉缺陷方面,发现NCACVT具有100%的敏感性和100%的特异性.结论:根据Harper和Reeves,这些特点使得这个试验成为一个可靠的、有创意的眼科实践筛选试验.     

Projected color slides as a method for mass screening of red-green color deficient individuals

University students (111, both male and female) were screened for red-green color deficiency using projected 35mm slides reproduced from Ishihara and H-R-R color plates. Ishihara and H-R-R color plates were tested in the same individuals at a second setting and the responses compared: 6.3% of the students were identified as color deficient by the Ishihara and 80.2% by the H-R-R projected slides while 5.4% were designated color blind by the Ishihara plates and 4.5% by the H-R-R plates. The sensitivity of both screening systems was 100%; the specificity of the Ishihara slides was 98.1% compared to only 20.8% for the H-R-R. The 9.8% prevalence of red-green deficiency detected by the Ishihara plates and 8.2% by the H-R-R plates for males is similar to the 6 to 9% frequency found for Caucasian males in other population studies. Within rigid guidelines, projected color slides have potential usefulness as a screening method for detecting individuals with red-green color deficiencies.     

黄色人工晶状体植入对比敏感度和色觉的研究

目的 研究黄色人工晶状体（ＩＯＬ）植入眼内主观感觉、对比敏感度和色觉的变化。方法老年白内障６０人（６６眼）,随机分成两组,植入黄色ＩＯＬ３０眼,普通ＰＭＭＡＩＯＬ３６眼。术后１周,１,３,６月时,分别询问主观感觉、测量视力对比敏感度、色觉。结果 黄色ＩＯＬ比普通ＰＭＭＡ ＩＯＬ在空间对比敏感度的低、中频率上显著长春市,主观感觉也较好。结论 黄色ＩＯＬ比普通ＰＭＭＡＩＯＬ在空间对比敏感度的低、中频率     

A simple modification of the Farnsworth-Munsell 100-Hue test for much faster assessment of color vision

Purpose:

The Farnsworth-Munsell (FM) 100-hue test is well known but is also time consuming, especially its analytical component. To reduce this needless time-waste during precious working hours, a simple modification was devised.

Design:

Prospective, comparative, observational study.

Materials and Methods:

A transparent clear plastic carrier box replaced the opaque one, allowing ready digital photodocumentation of top and bottom without even opening the box, or handling/inverting the caps -200 reportedly normals and 50 known color vision defectives could be easily tested on this modified-FM and results stored, allowing rapid turnover. The captured scores with patient ID were analyzed, at leisure, outside hospital time, saving 45-60 minutes/patient. After recording, the box was promptly handed over to the next subject for rearrangement. Times taken for test/patient were recorded.

Results:

Running time was reduced from 60-75 min to ~15 min/patient with no waste of invaluable lab hours. Turnover time is limited to capturing two photographs (~60 sec). The box is relatively cheap and easy to maintain.

Conclusions:

Our simplified FM 100-hue test allowed rapid assessment of color visions with easy data storage of both top and bottom.     

The effect of a moderate level of hypoxia on human color vision

This study reports the effect of a moderate level of hypoxia on human color discimination. We found a generalized loss of color vision affecting both red-green and blue-yellow discrimination at an altitude of 12,000 feet. Although the residual color discrimination at this altitude was within age-matched, sea-level norms, a statistically significant increase over sea level error scores was measured on the Farnsworth-Munsell 100-Hue test and the Pickford-Nicolson anomaloscope. An analysis of psychophysical and electrophysiological studies indicates that hypoxia acts by depressing retinal ganglion cell activity and that it can affect photopic visual processes as well as scotopic vision. We conclude that studies evaluating man's visual performance at altitude must consider post-receptoral processes.     

伊朗女中学生色觉缺失的患病率(英文)

色盲是常见病,先天性色盲X连锁隐性遗传。我们的研究中,随机分组抽样1600个女学生,进行Ishihara假同色表检查。其中0.63%色觉缺失,其中6例绿色弱(0.38%),4例红色弱(0.25%)。     

Changes of color vision in ocular hypertension

Fifty-six ocular hypertension (OHT) patients were examined for 2–3 days in the Eye Clinic of Kuopio University Hospital. No glaucomatous changes were found. Twenty-seven of them were found to have several risk factors for developing glaucoma and medication was started. Twenty-nine of the patients did not show risk factors and had no medication. Color vision was examined with the Farnsworth-Munsell 100 (FM 100) hue test and Besançon anomalometer, later Color Vision Meter 712 at the beginning of the study and 3 years later.None of the 56 patients showed any glaucomatous changes after 3 years of the study. In the treatment group, the FM 100 test showed significantly (paired t-test, p=0.004) improved error scores after 3 years. In the nontreatment group, 19 patients did not develop risk factors; they had no significant changes in the color vision results. In 10 patients of the non-treatment group, risk factors had developed with elevated intraocular pressure and medication was started for them after 3 years. Their color vision results in the blue anomalous quotient (AQ) of the anomalometer had significantly shifted to the blue part of the equation (paired t-test, p=0.04). The other color vision results had not changed significantly.The significantly improved FM 100 scores in the treatment group could mean, that the treatment has a beneficial effect for the OHT eyes at risk for developing glaucoma. The significant shifting of the blue AQ towards the blue part of the equation in the eyes with elevated pressure after 3 years could mean that minimal change in blue color vision measured by a blue anomaloscope might be a risk factor for glaucoma development.Abbreviations AQ anomalous quotient - FM-100 Farnsworth-Munsell 100 hue test - IOP intraocular pressure - MMP mid matching point - MR matching range - NS not significant - OHT ocular hypertension - S significant - SD standard deviation     

The Verriest Lecture 2009: Recent progress in understanding mammalian color vision

There have been significant advances in our understanding of mammalian color vision over the past 15 years. This paper reviews a number of topics that have been central to these recent efforts, including: (1) the extent and nature of ultraviolet vision in mammals, (2) the evolutionary loss of short‐wavelength‐sensitive cones in some mammals, (3) the possible roles of rod signals in mammalian color vision, (4) the evolution of mammalian color vision, and (5) recent laboratory investigations of animal color vision. Successes in linking opsin genes and photopigments to color vision have been key to the progress made on each of these issues.     

色觉形成的生物学机制研究进展

本研究综述了色觉形成的生物学机制。以M系统、P系统以及K系统为主线，描述了它们从光感受器到光感受器后的各类细胞（特别是各种神经节细胞），从神经节细胞到外膝核，从外膝核至大脑皮层有关功能区的研究进展，还讨论了三色理论、拮抗色理论的详细机制。     

What do color blind children really see? Guidelines for clinical prescreening based on recent findings

Recent research on classical red-green blind observers has shown that complete dichromacy may be present only under conditions where the viewing angle is small. For viewing angles greater than about 4 degrees, both rods and an anomalous cone have been shown to underlie a weak form of trichromacy. The conditions for rod or anomalous cone mediation of this trichromacy have also been shown to depend on the overall viewing luminance. These data taken together prompt a rethinking of the classical view of red-green dichromacy and lead to new considerations of the color discrimination performance of dichromatic candidates. In this paper we review the recent research on the presence of trichromatic abilities in classical dichromats and we relate these findings to the needs of the clinician, especially in the screening of young children.