Review of the main colour vision clinical assessment tests. / Revisión de los principales test clínicos para evaluar la visión del color.

INTRODUCTION: Congenital colour vision deficiencies affect 8% of the male and 0.5% of the female population. The study of colour vision is a complex process due to several factors: the psychophysics of vision itself, the difficulty to establish mathematical models for its analysis, the vague correlation of results between different tests, and the influence of external factors such as lighting, the tests condition, or the experience of the examiner and the patient. In the present document, a simplified review was carried out on the main colour vision tests available in clinical practice. MATERIAL AND METHODS: Once a filtered preliminary review was made of the bibliography related to the study of colour vision using the PubMed search tool, the most used tests in clinical practice were selected according to their frequency of use and the purpose for which they were applied. A bibliographic study was then carried out on each particular test according to the design of the shown stimuli, its target population, and its sensitivity and specificity. RESULTS: From the 95 publications found using the PubMed search tool, in 41 of them, colour tests were used by researchers in their methodology. From the 64 colour tests used, 19 of them were different (with 4 of them being different tests adapted by research groups, and 2 of them carried out online). The most used tests were the following: Ishihara test (10.88%), Farnsworth-Munsell (7.04%), Farnsworth-Munsell 100 Hue (6.4%), Cambridge Colour Test (3.84%), Hardy-Rand-Rittler (3.2%), tests developed by the groups (2.56%), the Anomaloscope (1.28%), the online tests (1.28%) and, finally, Colour Assessment and Diagnosis (0.64%), Pflüger Trident Colour Plates (0.64%), Toothguide Training Box (0.64%), Lanthony Desaturated D-15 (0.64%), City University Test (0.64%), Universal Colour Discrimination Test (0.64%), and Rabin Cone Contrast Test (0.64%). CONCLUSIONS: The Anomaloscope is the "gold standard" in terms of colour vision testing, despite its incompatibility with daily clinical practice. It is fairly complex to use, difficult to understand for children, and its practice requires having the time available. Nevertheless, it is possible to reach an accurate approximation through the combination of some of the tests listed in this article. The above mentioned tests are a good alternative to determine the presence of dyschromatopsia in settings closer to daily clinical practice or in less controlled settings than a clinical study. The major drawback among the wide range of tests available for the study of colour vision is the difficulty to compare results between tests, since units of the reported data are usually different, and experience is required for its correct interpretation. Currently, there is no consensus on which colour test is the most complete. It is, therefore, advisable to use at least 2 tests in order to ensure diagnoses, and have more extensive information about the visual perception of patients.

Prevalence of color vision deficiency among arc welders / Prevalencia de la deficiencia de la visión del color entre los soldadores con arco eléctrico

Purpose: This study was performed to investigate whether occupationally related color vision deficiency can occur from welding. Methods: A total of 50 male welders, who had been working as welders for at least 4 years, were randomly selected as case group, and 50 age matched non-welder men, who lived in the same area, were regarded as control group. Color vision was assessed using the Lanthony desatured panel D-15 test. The test was performed under the daylight fluorescent lamp with a spectral distribution of energy with a color temperature of 6500K and a color rendering index of 94 that provided 1000lx on the work plane. The test was carried out monocularly and no time limit was imposed. All data analysis were performed using SPSS, version 22. Results: The prevalence of dyschromatopsia among welders was 15% which was statistically higher than that of nonwelder group (2%) (p=0.001). Among welders with dyschromatopsia, color vision deficiency in 72.7% of cases was monocular. There was positive relationship between the employment length and color vision loss (p=0.04). Similarly, a significant correlation was found between the prevalence of color vision deficiency and average working hours of welding a day (p=0.025). Conclusions: Chronic exposure to welding light may cause color vision deficiency. The damage depends on the exposure duration and the length of their employment as welders (AU)

Objetivo: Este estudio se realizó para investigar si se puede producir una deficiencia de la visión del color relacionada con la profesión de soldador. Métodos: Se seleccionó como grupo del caso a un total de 50 soldadores que habían ejercido la profesión durante un mínimo de cuatro años, y se les comparó con 50 varones no soldadores que vivían en la misma zona, como grupo de control. Se evaluó la visión del color utilizando el test Lanthony D-15 desaturado. La prueba se llevó a cabo bajo la lámpara fluorescente de luz de día, con una distribución energética espectral con temperatura cromática de 6.500K y un índice de representación de 94 que aportaba 1000 lux en el plano de trabajo. La prueba se realizó de forma monocular, no imponiéndose ningún límite de tiempo. Los análisis de los datos se realizaron utilizando el software SPSS, versión 22. Resultados: La prevalencia de la discromatopsia entre los soldadores fue del 15%, lo cual fue estadísticamente superior al grupo de no soldadores (2%) (p=0,001). Entre los soldadores con discromatopsia, la deficiencia de la visión del color en el 72,7% de los casos fue monocular. Se produjo una relación positiva entre la duración del empleo y la pérdida de la visión del color (p=0,04). De forma similar, hallamos una correlación entre la prevalencia de la deficiencia de la visión del color y la media de horas laborales de una jornada de soldadura (p=0,025). Conclusiones: La exposición crónica a la luz de la soldadura puede causar una deficiencia de la visión del color. El daño depende de la duración de la exposición, y del tiempo en la profesión como soldadores (AU)

Multichannel perimetric alterations in systemic lupus erythematosus treated with hydroxychloroquine / Alteraciones de la perimetría multicanal en el lupus eritematoso sistémico tratado con hidroxicloroquina

Systemic lupus erythematosus (SLE) is a multiorgan autoimmune disease of unknown etiology with many clinical manifestations. We report the first case of SLE in which visual alterations were evaluated with multichannel perimetry. Some achromatic and color vision alterations may be present in SLE, especially when treated with hydroxychloroquine. The sensitivity losses detected in the chromatic channels in the central zone of the visual field were consistent with the results of the FM 100 Hue color test. Likewise, the multichannel perimetry detected sensitivity losses in the parafoveal area for both chromatic channels, especially for the blue-yellow (AU)

El lupus eritematoso sistémico (LES) es una enfermedad autoinmune multiorgánica de etiología desconocida, con muchas manifestaciones clínicas. Reportamos el primer caso de LES en el que se evaluaron las alteraciones visuales utilizando la perimetría multicanal. En el LES pueden presentarse ciertas alteraciones acromáticas y de la visión del color, especialmente cuando se trata la enfermedad con hidroxicloroquina. Las pérdidas de sensibilidad detectadas en los canales cromáticos de la zona central del campo visual fueron consistentes con los resultados de la prueba de color FM 100 Hue. De igual modo, la perimetría multicanal detectó pérdidas de sensibilidad en el área parafoveal para ambos canales cromáticos, y en especial para el azul-amarillo (AU)

Use of color lights for the detection of anomalies in quality systems.

The importance of eye care in the industry is a first level topic, due to most of the assembly and manufacturing aimed companies of various products that require direct health care of their employees, specially eye care. The lighting system, the lamp features and job tasks are factors that impact over the visual performance of the worker. Each of these factors, either by themselves or in conjunction, influences the visual performance of the employee, and therefore its safety and efficacy. Some of the reported symptoms are: problem of visual fixation, eye redness, tearing, headache, blurred vision, eyelids heaviness and dry eyes, [7]. The research was developed with 48 people, 27 male and 21 female, in the range of ages of 17 to 58 years old. In the experiment were used illumination system base on Diode Emitting lights (LED's) of five different colors (White, Blue, Green, Red and Yellow), the reason of use of LED's it is because are source of monochromatic light, also it is also saving power light and low heating dissipation.

[Colour comparison tests in unilateral optic neuropathies]. / Farbvergleichstests bei einseitigen Optikusneuropathien.

AIM OF THE STUDY: Colour comparison tests are a subjective supplement to the swinging flashlight test. We have investigated the specificity and sensitivity, compared 3 exactly defined different colours (red, green, blue), and looked for age relationships. METHOD: 101 patient with various unilateral optic neuropathies were compared to 103 age-correlated healthy controls in randomised order by letting the patient evaluate red, green and blue colour charts of 5.5 cm diameter. RESULTS: The area under the receiver operator characteristics curve was 0.804 for red, 0.821 for green and 0.789 for blue, and for any of the 3 colours 0.835 (at least one colour was seen differently). Best results were obtained when even small differences in colour perception were considered as pathological. 29 healthy controls perceived colours differently in both eyes, 24 of those being older than 50 years. The specificity decreased with age, was significant for green and red, not for blue. DISCUSSION: There were no significant differences between the 3 colours in all age groups. Evaluation of more than one colour does not increase the sensitivity significantly. Even small differences have to be considered as pathological to obtain the highest possible sensitivity. Test specifity decreases with age.

[Test-retest reliability of a web-based colour vision test]. / Untersuchungen zur Re-Test Reliabilität eines webbasierten Farbsehtests.

BACKGROUND: Screening tests should be simple, with high acceptance, low costs and offer a high sensitivity and specificity as well as high reliability. The test-retest reliability of a web-based colour vision test was evaluated. METHOD: The results of 386 subjects, who had performed the web-based colour vision test with 25 colour plates twice (available at http://www.farbsehtest.de), were analysed from an mySQL data base. Retests were performed spontaneously, normally on the same day, or through an email newsletter with a request to repeat the test. Test-retest reliability was assessed by calculating the kappa coefficient and the corresponding confidence interval. The McNemar test was used as a complementary procedure to detect the presence of systematic differences between test results. RESULTS: The kappa coefficient rises with increasing time interval between the first test performance and the test repetition. Thus it was 0.24 when the test was repeated within one hour (confidence interval 0.07 - 0.41, n = 63), it increases to 0.83 (confidence interval 0.75 - 0.92, n = 240) in the subjects who repeated the test at the earliest after two years. While the proportion of failed tests (< 3 mistakes) in the second test performance markedly decreases when the test is repeated in the short term within one hour (p < 0.001, McNemar), we were unable to identify any systematic differences (p = 0.602) for a time interval of more than one day. CONCLUSIONS: The web-based colour vision test is a reliable screening test with good reproducible results as well under uncontrolled examination conditions. Subjects must perform the test with serious intent and should not aim at a positive test result by training or manipulation because of self-delusion. Test results are reliable if the time interval between test and retest is more than one day.

The effect of illumination on gray color

The present study explored the perceptual process of integration of luminance information in the production of the gray color of an object placed in an environment viewed from a window. The mean luminance of the object was varied for each mean luminance of the environment. Participants matched the gray color of the object with that of Munsell chips in a viewing box. The results show that the Munsell values so obtained are linear measures of gray color. The results support the possibility that the gray color of the object derives from an additive integration of the information about mean luminance of the object and about mean luminance of the environment, with the weights of this information varying with the mean luminances(AU)

Categorical color constancy for simulated surfaces.

Color constancy is the ability to perceive constant surface colors under varying lighting conditions. Color constancy has traditionally been investigated with asymmetric matching, where stimuli are matched over two different contexts, or with achromatic settings, where a stimulus is made to appear gray. These methods deliver accurate information on the transformations of single points of color space under illuminant changes, but can be cumbersome and unintuitive for observers. Color naming is a fast and intuitive alternative to matching, allowing data collection from a large portion of color space. We asked observers to name the colors of 469 Munsell surfaces with known reflectance spectra simulated under five different illuminants. Observers were generally as consistent in naming the colors of surfaces under different illuminants as they were naming the colors of the same surfaces over time. The transformations in category boundaries caused by illuminant changes were generally small and could be explained well with simple linear models. Finally, an analysis of the pattern of naming consistency across color space revealed that largely the same hues were named consistently across illuminants and across observers even after correcting for category size effects. This indicates a possible relationship between perceptual color constancy and the ability to consistently communicate colors.

Locating basic Spanish colour categories in CIE L*u*v* space: Identification, lightness segregation and correspondence with English equivalents

Se realizaron cinco experimentos para identificar las categorías cromáticas básicas (CCB) del español y ubicarlas en el espacio CIE L*u*v*. Empleando una tarea de listas elicitadas y otra de denominación monolexémica libre, se confirmó la existencia de 11 CCB. Mediante una tarea de estimación de sinonimia, se concluyó que, en español, se emplean 2 términos sinónimos (morado y violeta) para denominar una categoría equivalente a la inglesa purple. Tres experimentos proporcionaron información acerca de la localización colorimétrica de las 11 CCB del español. Dos emplearon tareas de denominación monolexémica (libre y restringida) y el tercero requirió la señalización de prototipos y de buenos ejemplares. Se observó que las CCB del español y del inglés son esencialmente equivalentes en número y delimitación colorimétrica, por lo puede considerarse que nuestro trabajo extiende y complementa la investigación previa (sobre CCB inglesas) en lo referente a la localización de las categorías acromáticas en el espacio de color, los vínculos entre categorías cromáticas y acromáticas (ni rojo ni naranja tienen vínculos directos con las categorías acromáticas), y la dependencia de la claridad que muestra el uso de las CCB. Por último, destaca la existencia de 2 categorías próximas a ser básicas: beige y granate(AU)

Five experiments were performed to identify the basic Spanish colour categories (BCCs) and to locate them in the CIE L*u*v* space. The existence of 11 BCCs was confirmed using an elicited list task and a free monolexemic naming task. From the results provided by a synonymicity estimation task, it was concluded that, in Spanish, 2 synonymous terms (morado and violeta) are used to name a category equivalent to the English category purple. Three experiments provided information about the colourimetric localization of the 11 Spanish BCCs. Two experiments used monolexemic naming tasks (free and restricted) and a third required the free signalling of prototypes and good exemplars. It was observed that Spanish and British BCCs are essentially equivalents in number and colourimetric delimitation and, therefore, our work can be considered to extend and complement previous research (on English BCCs) insofar as achromatic categories in colour space localization, the links between chromatic and achromatic categories (red and orange have no direct links with achromatic categories), and the dependence of the use of BCCs on lightness are concerned. Lastly, our results indicate the existence of 2 categories that are nearly basic: beige and garnet(AU)

Color contrast in macaque V1.

We explored the neural basis for spatial color contrast (red looks redder surrounded by green) and temporal color contrast (red looks redder if preceded by green) in primary visual cortex (V1) of the alert macaque. Using pairs of stimuli, we found a subset of neurons that gave stronger responses to sequences of red and green spots and stronger responses to adjacent red and green spots. These cells combined their cone inputs linearly: for a red-ON-center cell, the sum of the OFF response to green and the ON response to red predicted the peak response to red preceded by green. These 'color' cells, which could underlie hue discrimination because they show cone opponency, could mediate spatial and temporal color contrast. In contrast, the majority of cortical cells, which do not show overt cone opponency but which are often orientation tuned and/or direction selective, are by themselves incapable of mediating hue discrimination. The remarkable degree of specialization shown by cells in V1, especially that of the double-opponent color cells, is discussed.

[Positive influence of color experience on result of color-arrangement-test Roth 28-hue (E) desaturated - a clinical study on 44 patients]. / Positiver Einfluss von Farberfahrung auf das Ergebnis von Farbsinnprüfungen mit dem Farbpigmentprobentest Roth 28-hue (E) desaturiert - Klinische Studie an 44 Probanden.

BACKGROUND: The color arrangement test can be applied for early diagnosis of diabetic retinopathy, even small confusion of colors influence clinical diagnosis. It is therefore necessary to be aware of influential factors. METHODS: Forty-four patients with color-experience (VW-Werk Wolfsburg) were included and devided in two groups: group 1: non-smokers without ophthalmological and systemic diseases (n = 27, 42+/-9 years), group 2: smokers without ophthalmological and systemic diseases (n = 17; 43+/-8 years). The control group 3 (n = 30; 42+/-4 years) included non-smokers and the control group 4 (n = 10; 42+/-8 years) smokers, both groups without color-experience, ophthalmological and systemic diseases. Besides the ophthalmological examinations (visual acuity, refraction, intraocular pressure, slit lamp and fundus examination) the color-vision was tested by the color-arrangement-test Roth 28-hue (E) desaturated monocularly under standard conditions: The background used was black cardboard, illuminated by two Osram fluorescent lamps (L36W/12LDL Daylight) providing 2000 lux at the test table. RESULTS: Ophthalmological examination in all subjects was without pathological findings. The mean error score in the non-smokers with color-experience (median+/-mean absolute deviation: 48+/-47) was lower than in the non-smokers without color experience (72+/-45; Mann-Withney-U-Test: p = 0.02). The mean error score in the smokers with color-experience (60+/-60) was lower than in the smokers without color-experience (156+/-65; p = 0.0014). No statistically significant difference was found between the measurements of the right and left eye (Wilcoxon-Test: group 1: p = 0.89; group 2: p = 0.9; group 3: p = 0.77; group 4: p = 0.87). CONCLUSION: Color experience improves the results in color-arrangement-tests like the Roth 28-hue (E) desaturated and should be considered in quantitative evaluation.

Color vision and occupational chemical exposures: I. An overview of tests and effects.

The paper presents a summary of the literature published until December 2000 on effects from some industrial chemical exposures on color perception, as well as short descriptions of the tests applied. Several different tests have been used to study acquired alterations of color vision. These changes are frequently found in the blue-yellow axis. Many of the tests were originally designed to detect congenital alterations in the red-green axis, and thus have relatively low sensitivity when studying chemically induced deficits in color perception. At present, the Lanthony D15-desaturated panel seems most suitable for application in industrial settings, since it is clearly the most sensitive and easily administered test. Color vision seems to be a physiological function very sensitive to several chemicals. The potency of industrial chemicals to induce color vision deficiencies has often been investigated during the last two decades. The chemicals most frequently studied are different solvents and mercury. Pronounced effects on color perception have been reported following chronic exposure to organic solvents such as styrene, carbon disulphide, perchloroethylene, n-hexane and solvent mixtures, and to organic as well as inorganic mercury. The effect of occupational toluene exposure seems not as well established, since only slight effects and several negative studies have been reported. For some of these compounds the effect on color vision has been further established through the finding of clear dose-effect relationships. In a few cases, even acute exposure situations, e.g. exposure to toluene for a few hours or acute alcohol intake, seem to affect color perception. Follow-up studies are needed to investigate the possible reversibility of effects in relation to discontinued or reduced exposures.

Color vision and occupational chemical exposures. II. Visual functions in non-exposed subjects.

This paper presents data on visual functions (visual acuity, contrast sensitivity, and several tests of color vision), in a group of 199 non-exposed healthy subjects with an even distribution over the age range 18-65 years, and sex. Although subjects with obvious congenital color vision deficiencies were removed from the analyses (four males), females were superior to males on several of the color vision tests applied. Age influenced visual acuity and contrast sensitivity, while color discrimination was less affected. Correlations between functions of the right and the left eye in the individual subjects were rather low, ranging from 0.40 to 0.73. Correlations between visual acuity and contrast sensitivity on the one hand and color discrimination ability on the other hand were still lower (r < 0.20). These low correlations between functions in the two eyes support the need for testing each eye separately.

Colour vision: Is colour constancy real?

Colour constancy is typically weaker in the laboratory than it seems in our everyday experience. New measurements using real-world stimuli show that colour constancy is in fact almost perfect, and that several different perceptual mechanisms contribute to achieving it.

[Functional study of the visual system in the cosmonaut by color campimetry]. / Issledovanie funktsional'nogo sostoianiia zritel'noi sistemy kosmonavta metodom tsvetovoi kampimetrii.

An investigation of series of experiments on the visual system dynamics carried out by cosmonaut-researcher Iurii Mikhailovich Baturin [correction of Yuri M. Batourin] in the piloted complex "Mir" in August 1998. The implementation of the method of the visual system investigation with the use of the luminance sensitivity thresholds to the stimuli of distinguished spectral components in different points of the visual field helps to clarify some negative dynamics of the visual system functional conditions reflected in the luminance sensitivity thresholds.

[The perceptive color space of the rabbit]. / Pertseptivnoe tsvetovoe prostranstvo krolika.

Discrimination of colors was studied using instrumental learning paradigm in three rabbits (Oryctolagus cuniculus). The rabbits were able to discriminate all but red stimuli by their color. The red stimulus could not be discriminated from the black one. The confusion matrix composed of probabilities of instrumental reactions was subjected to factor analysis in order to reveal the basic axes of the color perceptual space. The four-dimensional spherical structure of perceptual color space was obtained, which was different from that of trichromatic species in a reduction of color axes in red and yellow parts. The evidence characterizes rabbit as a protanopic animal.

[The characteristics of the color perceptive space in protanomals]. / Osobennosti tsvetovogo pertseptivnogo prostranstva protanomalov.

Color vision of three protanomal subjects was studied by means of direct paired comparison technique using 25 colors with different brightness. It was shown that the characteristics of their color vision could be completely and adequately described in the frames of the four-dimensional spherical model of color perception. The spatial axes could be identified as the two color-opponent mechanisms (red-green and blue-yellow) and the two achromatic mechanisms (brightness and darkness). Deformation of the color axes in protanomals (as compared with the normal trichromatics) was demonstrated in the "red" and "yellow" spectral region. The visual disturbance in protanomal subjects involves not only color but also achromatic mechanisms. This is manifested in the a deformation of perceptual brightness scale. In comparison with normal trichromatic subjects, the protanomals perceive the red and adjacent colors as achromatic while green, yellow-green, and orange as more bright but low-saturated colors.

[The discrimination of color images in human operative memory]. / Razlichenie tsvetovykh obrazov v operativnoi pamiati cheloveka.

Qualitative changes of color image maintained in the operative memory were studied using the modified Sperling's strategy. On the basis of estimations of difference between any two color images (from nine possible), contained in the same memory volume within 50 and 100 ms, the respective mnemonic spaces were built and afterwards correlated with the perceptual and semantic spaces. It was found out that the maintenance of a color image in the operative memory was affected by two simultaneous but independent factors. The first factor described the fading, i.e., extent of the intensity loss of the primary color image in the process of its maintenance in the operative memory. Fading was accompanied by a decrease in the signal-to-noise ratio and increase in the incidence of the casual mistakes in comparing the images with each other. The second factor determined the systematic transformation of color images in the memory expressed in the effect of clusterization of point stimuli and specific change in the between-point distances (estimations of difference).

Changes in perceived color with intermittent illumination.

Using 24 observers with normal color vision, perceived shifts in hue were determined for a yellow-red, green, and blue-green at intermittencies of 5, 10, and 20 cps. The hue shift for yellow-red was consistent with the hue shift exhibited by a deuteranomalous observer while the hue shift for green and blue-green was consistent with that exhibited by a protanomalous observer.

Impaired color vision in cocaine-withdrawn patients.

BACKGROUND: The main reinforcing effect of cocaine happens by altering dopaminergic neurotransmission in the brain reward systems. Dopamine is found in high concentrations in the retina in which it plays an important role in color vision. Therefore, we investigated whether cocaine-dependent patients might have impaired color vision. METHODS: We compared patients recently withdrawn from cocaine (n = 31) with matched normal controls (n = 31) on 2 color vision tests. RESULTS: Cocaine-withdrawn patients had significantly higher error scores than matched controls on the Farnsworth-Munsell 100-hue and Lanthony desaturated D-15 color vision tests. Also, 23 of the 31 cocaine-withdrawn patients had blue-yellow color vision losses on the Farnsworth-Munsell 100-hue test compared with 3 controls (P < .001, chi 2 test) and 15 had blue-yellow color vision loss on the Lanthony desaturated D-15 test compared with 2 controls (P < .001, chi 2 test). CONCLUSIONS: These significantly higher test error scores and blue-yellow color vision losses suggest that color vision is impaired in cocaine-withdrawn patients. Color vision testing may be useful in future studies of cocaine-dependent patients.