Color Discrimination Test Research Articles

Mercury toxicity in the Amazon: contrast sensitivity and color discrimination of subjects exposed to mercury

We measured visual performance in achromatic and chromatic spatial tasks of mercury-exposed subjects and compared the results with norms obtained from healthy individuals of similar age. Data were obtained for a group of 28 mercury-exposed subjects, comprising 20 Amazonian gold miners, 2 inhabitants of Amazonian riverside communities, and 6 laboratory technicians, who asked for medical care. Statistical norms were generated by testing healthy control subjects divided into three age groups. The performance of a substantial proportion of the mercury-exposed subjects was below the norms in all of these tasks. Eleven of 20 subjects (55%) performed below the norms in the achromatic contrast sensitivity task. The mercury-exposed subjects also had lower red-green contrast sensitivity deficits at all tested spatial frequencies (9/11 subjects; 81%). Three gold miners and 1 riverine (4/19 subjects, 21%) performed worse than normal subjects making more mistakes in the color arrangement test. Five of 10 subjects tested (50%), comprising 2 gold miners, 2 technicians, and 1 riverine, performed worse than normal in the color discrimination test, having areas of one or more MacAdam ellipse larger than normal subjects and high color discrimination thresholds at least in one color locus. These data indicate that psychophysical assessment can be used to quantify the degree of visual impairment of mercury-exposed subjects. They also suggest that some spatial tests such as the measurement of red-green chromatic contrast are sufficiently sensitive to detect visual dysfunction caused by mercury toxicity.

Multifocal Electroretinography, Color Discrimination and Ocular Toxicity in Tamoxifen Use

Purpose: To study prospectively retinal function, color discrimination, and ocular toxicity in women treated with standard-dosage tamoxifen for breast cancer. Methods: Thirty visually asymptomatic patients with at least 2 years of continuous tamoxifen therapy underwent multifocal electroretinography (ERG), color discrimination testing, and ophthalmic examination. The results were compared with 17 patients who were not taking tamoxifen after breast cancer surgery and to an additional age-matched group of 21 healthy women. Results: Multifocal electroretinogram amplitudes and latencies were comparable among the three studied groups, and individual recordings were within age norms from our own lab. In the treated group, mild diffuse color vision loss was found in two patients with normal fundi. Three other patients had ocular toxic effects, with two cases of refractile retinal crystals and one case of keratopathy. Conclusions: The aspects of central retinal function that are assessed by multifocal ERG were not affected even after at least 2 years of tamoxifen use, suggesting that the multifocal ERG is not sufficiently sensitive to detect tamoxifen-associated change that might occur. Some degree of color vision loss and ocular toxic effects were found in a few cases of this cohort suggesting that women using tamoxifen should receive an eye exam at least as often as recommended for middle-aged people.

Evaluation of cerebral dyschromatopsia using color afterimage

Cerebral dyschromatopsia is traditionally evaluated by color discrimination tests such as the Farnsworth-Maunsell 100 Hue Test. These tests are also used to evaluate color-perception deficits caused by eye disease, and they do not tell us whether color perception is impaired in the eye or in the brain. Here, we used color afterimage to isolate color-perception deficits in the brain from those in the eyes, in a patient with cerebral dyschromatopsia. The results showed that the patient perceived color afterimage of yellow and blue with abnormal duration and chromaticity. On the other hand, the patient performed normally on the Farnsworth-Maunsell 100 Hue Test. We conclude that the color afterimage test would be useful to evaluate color perception in the brain.

Demonstration of a genotype–phenotype correlation in the polymorphic color vision of a non‐callitrichine New World monkey, capuchin (Cebus apella)

Color-vision polymorphism in New World monkeys occurs because of an allelic polymorphism of the single-copy red-green middle-to-long-wavelength-sensitive (M/LWS) opsin gene on the X chromosome. Because color-vision types can readily be estimated from allelic types of the M/LWS opsin gene, this polymorphic system offers researchers an excellent opportunity to study the association between vision and behavior. As a prerequisite for such studies, genetically determined color-vision types must be concordant with phenotypes determined directly by behavioral criteria (e.g., by a color discrimination test). However, such correlations between genotypes and phenotypes have been studied only for callitrichine species. Using genetic, electrophysiological, and behavioral approaches, we evaluated the color vision of brown capuchin monkeys (Cebus apella), a representative non-callitrichine model animal for physiology and behavior. Two allelic M/LWS opsins-P545 and P530-were identified in the studied captive population. Females had one or both of the alleles, and males had either one. The retinal sensitivity in P530 dichromats was short-wave shifted relative to that in P545 dichromats, whereas that in P530/P545 trichromats was between the two groups. In a discrimination task using Ishihara pseudo-isochromatic plates, P530/P545 trichromats were successful in discriminating stimuli that P530 and P545 dichromats were unable to discriminate. In a food-search task, P530/P545 trichromats were able to locate red targets among green distracters as quickly as among white distracters, whereas both types of dichromats took longer. These results demonstrate the mutual consistency between genotypes and phenotypes of color vision, and provide a solid genetic basis on which the ecology and evolution of color vision can be investigated.

Long‐term macular function in eyes with central serous chorioretinopathy

This study aimed to investigate the long-term effects of central serous chorioretinopathy (CSCR) on macular function. Sixty-two eyes of 31 patients were included in this study. All patients were diagnosed with unilateral CSCR at the Retina Unit of the Ophthalmology Department, Trakya University Medical Faculty, and had a post-attack bilateral visual acuity of 6/6 and a follow-up period of a minimum of 6 months. Visual function was assessed using the Amsler grid, 40-hue colour discrimination test, visual field examination by means of Octopus automatic perimeter and Cambridge contrast sensitivity tests. Of the 31 patients, 71% were men and 29% were women, with a mean age of 39.3 +/- 7.6 years. The patients had a mean follow-up period of 50.6 +/- 40.5 months after the acute attack. Metamorphopsia was observed in 67.7% of the cases with CSCR. A colour discrimination defect was found in 48.4% of the CSCR eyes and in 54.8% of the fellow eyes. As compared with the fellow eyes, the mean deviation in the central 10 degrees of visual field was significantly higher (t = 2.9, P = 0.007) and the mean contrast sensitivity score was significantly lower (t = -3.2, P = 0.004) in the CSCR eyes. Patients with unilateral CSCR were observed to have long-term bilateral colour discrimination defects, and eyes with clinical CSCR were determined to have central relative scotoma and loss of contrast sensitivity.

Short Communication: Colour vision and proficiency in diagnostic microscopy

The microscopical diagnosis of infectious diseases is an essential medical laboratory service in resource-poor countries. We conducted an external quality assessment (EQA) of peripheral laboratories in southern Ethiopia using a panel of 20 ready-prepared sputum and blood smears containing either no pathogens or locally common pathogens. Microscopists also undertook a colour discrimination test (Farnsworth-Munsell 100 hue test). Twenty microscopists from 10 health centres participated. Their microscopy results were compared with that of the EQA controllers. Their Kappa indices of agreement ranged from 0.1 to 0.89 (mean+/-SD: 0.58+/-0.21). Kappa values were analysed according to microscopists' colour discrimination ability. The Kappa indices for the correct reading of diagnostic smears were associated with the colour vision ability of the technicians. Our results suggest that routine quality improvement activities may not achieve their desired effect if the colour discrimination abilities of technicians are not considered.

Brain but not lung functions impaired after a chlorine incident.

A workplace bleach exposure incident was studied in 13 women to determine whether chlorine caused neurobehavioral and pulmonary functional effects. We compared neurophysiological and neuropsychological measurements in 13 chlorine-exposed women, 4.5 years after exposure, and 41 unexposed women. Reaction times, balance, blink reflex latency, color discrimination and several psychological tests were measured. Pulmonary function was assessed by spirometry. A profile of mood states and frequencies of 35 symptoms were obtained. Chlorine exposed women performed statistically significantly below unexposed women for simple and choice reaction times, balance with eyes open and eyes closed, color discrimination, grip strength, Culture Fair, digit symbol substitution, vocabulary, trail making B and pegboard. Profile of mood states scores and frequency symptoms were elevated. Respiratory symptoms were elevated but pulmonary volumes and flows were not reduced. Chlorine bleach exposure was associated with impaired neurobehavioral functions and elevated POMS scores and symptom frequencies. Alternatives to chlorine should be used.

A double-blind placebo-controlled evaluation of the acute effects of sildenafil citrate (Viagra) on visual function in subjects with early-stage age-related macular degeneration

PURPOSE: To assess the effects of a single 100-mg dose of sildenafil citrate on visual function in men with early-stage age-related macular degeneration. DESIGN: Randomized double-blind placebo-controlled clinical trial. METHODS: Nine men (mean age 71 years, range 59–85 years) with early-stage (minimal visual impairment and large drusen in the macula) age-related macular degeneration and 20/40 or better-corrected visual acuity in at least one eye were prospectively randomized to receive either placebo or sildenafil citrate (Viagra; Pfizer Inc, New York, New York) 100 mg as a single oral dose. After 7–14 days, they received the alternate treatment. Subjects underwent visual acuity, Amsler grid, color discrimination (D15), traffic light, Humphrey perimetry, and photo-stress testing in each eye before and at specific intervals within 8 hours after dosing. RESULTS: Compared with placebo, no pattern of errors were evident in any visual function test following sildenafil administration. No statistically or clinically relevant changes from baseline were observed in visual acuity, Humphrey perimetry (corrected pattern standard deviation), D15 color discrimination, or photo-stress tests. No clinically relevant changes were observed in the Amsler grid or traffic light tests. Sildenafil treatment was associated with transient mild or moderate headache, flushing, and rhinitis. There were no visual adverse events spontaneously reported to the investigator. CONCLUSION: A single 100-mg dose of sildenafil was well tolerated and produced no acute visual effects or exacerbation of preexisting visual impairment in nine men with early-stage age-related macular degeneration.

Visual tests for measuring the picture quality of teleconsultations for medical purposes

Telemedicine provides a new way of delivering medical services. The good quality of the picture is, however, essential for a proper and reliable teleconsultation, especially in the cases when visual information about the patient's physical condition is of great importance as in ophthalmology and dermatology. Therefore real-time telemedical applications need standards for these procedures, e.g. minimum requirements for resolution, as well as contrast and color discrimination. The present study was carried out to test these parameters in a real environment. A panel of different resolution, contrast sensitivity and color discrimination tests was carried out for five test persons via PictureTel videoconference system by ISDN 128 kbit/s line speed and in a normal way. The good color discrimination of the teleconsultation system makes it possible to use the system in the evaluation of different skin lesions and exemas. However, the poor resolution and especially poor contrast sensitivity makes the use of the equipment valueless in the evaluation of diseases where the diagnoses are based on the discrimination of small details, like the biomicroscopical analysis of inflammatory cells in the aqua's humor in cases of intraocular inflammation. The authors are suggesting a simple panel of tests to optimize and standardize these parameters.

A new colour vision arrangement test to detect functional changes in diabetic macular oedema

AIMA study was undertaken to investigate the correlation between colour discrimination tests and the presence of macular oedema in patients with type I diabetes to find a sensitive diagnostic tool...

Color acceptance of direct dental restorative materials by human observers

The purposes of this study were to evaluate the CIELAB, CMC (2:1), and CMC (1:1) formulas to identify which provides the best indicator for acceptability of small color differences in the esthetic dental restorative materials, to determine if different groups of observers have different levels of acceptability, and to estimate the color difference that would indicate acceptability between a restoration and an adjacent tooth. The subject population of human observers was divided into four groups, each containing 12 subjects. The composition of the groups were: Group 1, dental auxiliaries and hygienists; Group 2, dentists; Group 3, dental materials scientists; and Group 4, patients. A color vision screening test was administered to each subject to ensure that only observers with normal color vision were evaluated. A composite resin color discrimination test was developed specifically for this study. This test was composed of six sets of discs fabricated from dental composite resin restorative materials. Each set consisted of one standard disc representing tooth color. In each set, six discs representing composite resin restorations were matched to the standard disc for a total of 36 pairings in the test. Color differences between the standard discs and the restoration discs were calculated in CIELAB, CMC (1:1), and CMC (2:1) color units. The subjects were asked to evaluate the composite resin materials as to acceptability of color differences between the disc pairs. The data were analyzed by logistic regression analysis for each observer and by each ΔE formula to generate receiver operating characteristics (ROC) curves. The areas under these ROC curves were calculated and ranked. ANOVA and Tukey's Studentized Range (HSD) Test were applied to the ranks. In regard to the acceptance of dental restorations based solely on color difference, the CMC (1:1) color difference formula gave better correlation than the CIELAB formula for small color differences in the esthetic dental restorative materials. There were significant differences found between the experiment groups in regard to acceptability of color differences using the CMC (1:1) and CIELAB formulas. The dental hygienist/auxiliaries group proved to be more discriminating in accepting differences between tooth and composite resin restorative material color than patients. The mean 50:50 ΔE replacement points for all subjects were 2.29 and 2.72 color units for the CMC (1:1) and CIELAB formulas, respectively. © 2000 John Wiley & Sons, Inc. Col Res Appl, 25, 278–285, 2000

Variability of stimulus detection, form discrimination, and color recognition with suprathreshold campimetry in brain-damaged patients

This study was performed to assess the reliability of a new method of suprathreshold stimulus detection campimetry and color and form campimetry, and especially to analyze learning effects in the application of these methods. A total of 27 patients (mean age 53.2±17.7 years) with postchiasmatic damage of the visual system were examined on five different occasions with computer-based campimetric tests of suprathreshold stimulus detection (PeriMa), form recognition (Peri-Form), and color discrimination (PeriColor). Either 250 or 500 stimuli were presented on a 17? CRT monitor to achieve high-resolution campimetry in the central visual field (±21.5° vertical and ±27° horizontal eccentricity). Average correlations of the number of detected/correctly recognized stimuli in five consecutive measurements ranged from r=0.86 to r=0.94. As a measure of the variability of visual field size, the individual standard deviation of the five results of each test was taken (stimulus detection: ±4.2%, form recognition: ±6.2%, color recognition: ±6.4%). A measurement of horizontal distances between the vertical meridian and the border of the defective area at the positions of upper/lower 20°, upper/lower 10° and 0°, showed average individual standard deviations between ±1.9° and ±2.9° of visual angle. Correlations between visual field variability and (a) physical health and subjective mental condition, (b) patient’s age, (c) sustained attention, (d) size of defective field, and (e) cause of lesion were small and not significant. We found a learning effect from the first to the fifth measurement, defined as the average increase of detected/correctly recognized stimuli, amounting to 3.1% (stimulus detection), 3.0% (form recognition), and 9.0% (color discrimination, all). To achieve homogeneity of variances and to reduce the influence of the size of the defective field, we used the standard deviation from the individual mean (as 100%) of each patient for further statistical analyses. After this transformation, average deviations from the individual mean of detected/correctly recognized stimuli of each patient were considerably increased: ±9.7% (PeriMa), ±13.8% (PeriForm), and ±12.4% (PeriColor). ANOVA showed significant learning effects. An investigation of horizontal distances from the vertical meridian showed learning effects especially in Periform (+1.7°) and in Pericolor (+2.8°).

Broad-band visual capacities are not selectively impaired in Alzheimer's disease

Histological examination of the optic nerves of Alzheimer's disease (AD) patients has revealed a selective degeneration of large axon ganglion cells. This morphological abnormality raises the possibility of a selective impairment of broad-band channel visual function. To test this hypothesis, we administered visual psychophysical tests associated with either the color-opponent or the broad-band retinocortical channel to 14 AD patients and 29 elderly control subjects (ECS). In previous studies in monkeys, these tests had been sensitive to the effects of either parvocellular or magnocellular LGN lesions. In the present study, the color-opponent channel was assessed by tests of texture and color discrimination; the broad-band channel was assessed by tests of flicker and motion detection. Logistic regression analysis indicated that all tests collectively discriminated diagnostic groups at a borderline level of significance ( p = 0.09). ANOVA also indicated a trend towards overall depressed function for AD patients on some capacities tested. Analyses comparing the prevalence of deficits in the AD and ECS groups showed that a significantly greater number of AD patients than ECS had deficits on texture discrimination, blue-violet discrimination, and 4.72°/s motion detection. No individual subject demonstrated a selective impairment of broad-band channel function. The visual deficits in AD did not resemble those caused by lesions of magnocellular LGN in monkeys, indicating that the visual impairment in AD is not a functional reflection of damage limited to the broad-band channel. Rather, the perceptual deficits we observed may be due to neuropathological changes in visual association cortices, particularly the ventral visual pathway, in which parvocellular as well as magnocellular capacities are represented. The deficits are found in a subset of AD patients, suggesting that they are not an obligatory correlate of mild to moderate AD but, instead, reflect individual differences in the distribution of neuropathological changes in visual cortices.

色彩弁別能力に関する研究

With the aim of evaluating training and improving the ability to distinguish colors necessary for developing an esthetical prosthetic appliance, 20 dental students of our university were subjected to color discrimination tests to evaluate their ability, and the following results were obtained.1. The ability to distinguish red, yellow, green and purple colors was judged to be fair in 19 (95%) students and excellent in one (5%) student.2. When the results were analyzed by sex, males showed the highest ability for distinguishing red colors, followed by green, yellow and purple colors; the ability to distinguish purple colors was particularly low. In females, the corresponding order was red, green, purple and yellow, and their ability to distinguish red colors was at the same level as that for green colors, and their ability to distinguish purple colors was at the same level as that for yellow colors.3. In all subjects, the ability to distinguish red and green colors was relatively high, while that for yellow and purple colors was relatively low.

Color discrimination testing reveals early printshop solvent neurotoxicity better than a neuropsychological test battery

Twenty standardized neuropsychological tests were compared to the Lanthony D-15 desaturated panel test of chromotopsia to determine which measures would most effectively discriminate solvent-exposed print workers from controls. All the workers of the printing services of Université du Québec a Montréal (N = 29) were assessed excepted one who refused to participate. Twenty-nine workers (employed on a full time basis) matched for occupation, age, sex, education, vocabulary, and written arithmetic (p >.13) with the print workers served as controls. Air samples revealed exposure to ethanol, perchloroethylene, methyl chloride, xylene, toluene, and stoddard solvent in the print shop. None of the 20 neuropsychological measures yielded a statistically significant decrement in the print workers. On the other hand, the Lanthony D-15 test revealed a significant group difference (p <.01) and a highly significant interaction between job category within the print shop and dyschromatopsia (p <.001) - the graphists, photocopiers, and printers/binders manifesting increasing severity of impairment as a function of increasing magnitude, and/or type, of dose. The results were interpreted to mean that in a cohort of printers with low seniority (10.42 years) such as this one, neuro-opthalmotoxic effects can be observed earlier than putative neuropsychotoxic effects with the tools at hand.

Clinical measures of central vision function in glaucoma and ocular hypertension.

A generalized loss of visual sensitivity, even for foveal targets, has been reported as an early sign of glaucoma. In the present study of central vision, we used relatively simple and rapid clinical tests of color thresholds, color discrimination, and spatial contrast sensitivity to compare the vision of three age-matched groups of patients who had primary open angle glaucoma (n = 33) or ocular hypertension (n = 32) as well as normal subjects (n = 24). The largest sensitivity losses for both glaucoma and ocular hypertensive groups were disclosed by a color threshold test with blue lights designed to isolate the blue-sensitive pathways of the visual system. The loss of sensitivity for both the glaucoma group and the ocular hypertensive group is consistent with recent reports (from postmortem studies of human eyes) of extensive axon death even in the absence of glaucomatous field defects.

Color vision polymorphism and its photopigment basis in a callitrichid monkey ( Saguinus fuscicollis)

The color vision of five saddle-backed tamarins ( Saguinus fuscicollis) was studied. Behavioral tests of color discrimination and spectral sensitivity indicate that this species has a color vision polymorphism. Individual monkeys have either dichromatic or trichromatic color vision. Measurements of the spectral sensitivity of cones on this species were made on nine animals with the technique of electroretinogram (ERG) flicker photometry. Both the electrophysiological and the behavioral results suggest that there are four classes of cone pigment in this species. In addition to a short wavelength sensitive cone, apparently common to all tamarins, there are three classes of middle to long wavelength cone (λ max = 545, 557 and 562 nm). Individual animals have either one or two of the latter types. The color vision variation in this species differs for males and females.

Color-discrimination tests on fibers in ground squirrel optic nerve.

Color-discrimination tests on fibers in ground squirrel optic nerve.G H Jacobs, B Blakeslee, and R B TootellG H Jacobs, B Blakeslee, and R B TootellPublished Online:01 May 1981https://doi.org/10.1152/jn.1981.45.5.903MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByRetinal inputs to the geniculate relay cells in the eastern chipmunk (Tamias sibiricus asiaticus): a comparison between color and non-color sensitive cellsBrain Research, Vol. 404, No. 1-2Intensity coding and luxotonic activity in the ground squirrel lateral geniculate nucleusVision Research, Vol. 27, No. 12Shouldn't directional movement detection necessarily be “colour-blind”?Vision Research, Vol. 25, No. 7Refractive state, depth of focus and accommodation of the eye of the California ground squirrel (Spermophilus Beecheyi)Vision Research, Vol. 24, No. 10 More from this issue > Volume 45Issue 5May 1981Pages 903-14 https://doi.org/10.1152/jn.1981.45.5.903PubMed7241176History Published online 1 May 1981 Published in print 1 May 1981 Metrics

Report on a group form for the measurement of color-word interference: speed of color discrimination test.

Although there have been some suggestions towards the development of a standardized form for a group version of Stroop's color-word interference test yet, to some extent, a group form has not been applied in psychological research. In this study the equivalence of group and individual procedures as well as some standards for psychological tests of the group form were examined. The results show that the interference score does not comply with the requirements of psychological tests and the equivalence of the interference scores of the group and individual procedures could not be determined. For further research experimental analysis of convergent and discriminant validity is suggested.

Field-dependence-independence as "sensitivity" of the nervous system: supportive evidence with color and weight discrimination.

Consistent with a conceptualization of field-dependence as a partially genetically based “sensitivity” of the nervous system, it was hypothesized that field-independent Ss would perform better than field-dependent Ss on tests of color and weight discrimination. 56 Ss selected as extreme on tests of both field-dependence—independence and introversion—extraversion performed color and weight discrimination tasks. The color discrimination results very strongly support the hypothesis. The weight data provide additional support, but weight discrimination appears to interact with introversion—extraversion in addition to being related to field-dependence.