Color signal systems for the red-green color blind: an experimental test of the three-color signal system proposed by Judd.
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Color↗
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Results for “Color Vision Defects”
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A simple screening test for color matching in dentistry.
This study compared a simple and readily available shade guide color-matching test with the general industry standard test for color discrimination. This study indicates that a simple screening test for color defective vision and color discrimination skills in dentistry can be performed by matching two Vita-Lumin shade guides. Those dental office personnel who score a low number of matches in the Vita test (that is, seven or fewer correct matches) should have additional color discrimination testing and refer shade matching to other personnel with higher scores.
Adult↗
[The Medical Union of Canada in 1883; color blindness in railway navigation reports].
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Canada↗
Typical total color blindness reinterpreted.
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Color Perception↗
Visual function in neurofibromatosis.
OBJECTIVES: To evaluate the visual function in patients with neurofibromatosis (NF) and to study the etiology and incidence of visual dysfunction associated with NF. PATIENTS AND METHODS: A total of 75 patient with diagnostic criteria for NF were evaluated. Neuro-ophthalmological examination as well as electrophysiological and imaging studies were performed. Special attention was given to the presence of visual dysfunction and to its correlation with the ophthalmic changes that were found. RESULTS: Ocular findings were present in 42 (56%) patients. Visual dysfunction was identified in only 11 (14.7%) patients. Visual acuity decrease was the most prevalent change, being present in eight (72.7%) of patients with visual dysfunction. Nystagmus, strabismus, visual field defects, and color vision defects were also detected. Therapy is also reviewed. The prognosis of the 11 patients with visual dysfunction was unfavorable, and is discussed. CONCLUSION: The prevalence of NF and ophthalmological findings related to it make the problem of visual dysfunction in NF a serious one, deserving of the attention of all ophthalmologists. Clinical examination, associated with complementary diagnostic techniques (mainly imaging studies), allows NF's identification, definition, and therapy. The high prevalence of asymptomatic ocular findings in NF (73.8%) highlights the role of imaging techniques in its evaluation.
Adolescent↗
[Monocular tests for color vision in normals and color defectives].
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Biometry↗
Color vision testing.
The science of color vision testing has evolved since its inception in the late 1700s. Since then, the rudimentary technique of comparing color names has been replaced by more sophisticated methods. Commonly used tests in clinical practice today include isochromatic plates, arrangement tests, anomaloscopes, and lantern tests. Each category has unique attributes that make it suitable for a particular clinical situation. The clinician should be aware of the requirements for administering and grading each test type. Factors such as the quality of the illuminant and the size of the field of view are important elements in setting up a proper color vision laboratory. Currently, no treatment exists for congenital color vision defects. However, studies show that diagnosis of these defects early in life may help children adjust better to tasks at school and may help adults understand their limitations at work. Acquired color vision defects are often used as markers of ocular pathology in the clinical setting. Different color vision tests are appropriate for diagnosing the different categories of defects. Sometimes, a battery of tests may be appropriate. This paper is a review of the current knowledge in the field of color vision testing.
Color Perception↗
Computerized color-vision test based upon postreceptoral channel sensitivities.
An automated, computerized color-vision test was designed to diagnose congenital red-green color-vision defects. The observer viewed a yellow appearing CRT screen. The principle was to measure increment thresholds for three different chromaticities, the background yellow, a red, and a green chromaticity. Spatial and temporal parameters were chosen to favor parvocellular pathway mediation of thresholds. Thresholds for the three test stimuli were estimated by four-alternative forced-choice (4AFC), randomly interleaved staircases. Four 1.5-deg, 4.2 cd/m2 square pedestals were arranged as a 2 x 2 matrix around the center of the display with 15-minute separations. A trial incremented all four squares by 1.0 cd/m2 for 133 ms. One randomly chosen square included an extra increment of a test chromaticity. The observer identified the different appearing square using the cursor. Administration time was approximately 5 minutes. Normal trichromats showed clear Sloan notch as defined by log (deltaY/deltaR), whereas red-green color defectives generally showed little or no Sloan notch, indicating that their thresholds were mediated by their luminance system, not by the chromatic system. Data from 107 normal trichromats showed a mean Sloan notch of 0.654 (SD = 0.123). Among 16 color-vision defectives tested (2 protanopes, 1 protanomal, 6 deuteranopes, & 7 deuteranomals), the Sloan notch was between -0.062 and 0.353 for deutans and was < -0.10 for protans. A sufficient number of color-defective observers have not yet been tested to determine whether the test can reliably discriminate between protans and deutans. Nevertheless, the current data show that the test can work as a quick diagnostic procedure (functional trichromatism or dichromatism) of red-green color-vision defect.
Automation↗
Sahlgren's Saturation Test for acquired dyschromatopsia: increased lightness enhances sensitivity.
Sahlgren's Saturation Test (SST) is a simple sorting test designed for the detection and grading of acquired color vision defects. Like other pigment-based color vision tests, the SST color samples have medium lightness, i.e., they belong to the intermediate part of the gray scale. We tested normal controls and subjects with congenital or acquired dyschromatopsia with five SST versions that differed only in the amount of lightness. The sensitivity of the test increased considerably with increasing lightness. Therefore, the lightness level of SST has now been changed from 30 to 10 Natural Color System units.
Color↗
[Dyschromatopsias and pictorial art].
The influence of color vision defects on pictorial art was studied using three methods. 1) From a theoretical standpoint, the possibilities of choice of the color-blind painter are determined by the nature of his color perception. Characteristic errors result from the fact that he has to choose between many hues which are different to a normal individual but which all look the same to him. 2) Evaluation of the clinical cases of painters with dyschromatopsias has shown evidence of the following: a) the color-blind painter makes mistakes according to the type of color defect; b) if the color-blind painter makes several copies of the same model, he makes different mistakes at each attempt; c) when several color-blind painters make copies of the same model, they also make different mistakes, even when they suffer from the same type of color vision defect. Preferences for some colored patterns were studied by means of a forced choice procedure and choices of color-blind individuals were often characteristic of their dyschromatopsia. Recent clinical case of acquired dyschromatopsia reported in the literature are discussed, as is a personal case of a painter suffering from tapeto-retinal degeneration. This was a severe dyschromatopsia with a neutral zone in purple (so-called scotpic axis, by Verriest's terminology). The painting of this artist tended to be monochromatic, mainly in green and green-blue colors. 3) Recent studies in art history have shown that only the romantic etcher Meryon was definitively color deficient. The more dubious cases of the Polish painter Grottger and of Eugène Carrière are discussed and conclusions are negative. Among acquired dyschromatopsias, there have been many recent papers devoted to cataract dyschromatopsias, concerning the cases of Rouault, Monet and Mary Cassatt. The hypothesis of a degree of chromatopsia or dyschromatopsia of toxic origin in the case of Van Gogh is also assessed. In conclusion, the problem of the relations between congenital or acquired dyschromatopsias and pictorial art seems very complex and great care is required when making deductions and advancing hypotheses.
Color Perception↗
Dichromacy and its effect on a young male.
Deuteranopia is a dichromatic color vision defect which may cause problems for an individual asked to perform color-oriented tasks. This can especially create problems for grade school children in classrooms whose instructional material depends heavily on color. This case report presents a child with a deuteranopic color vision defect who was mistakenly labeled learning disabled because of his inability to learn and perform color oriented tasks.
Child↗
Prevalence of congenital color deficiencies in secondary-school students in Tehran.
PURPOSE: A population-based study was conducted to determine the prevalence of color deficiencies in secondary-school students (ages 12-14) in Tehran. METHODS: A total of 2,058 students (1,136 males, 922 females) were examined with Ishihara pseudoisochromatic color plates. RESULTS: In the study population, 97 cases of defective color vision were detected, including 93 males and 4 females. The affected individuals all had negative histories of previous systemic and ocular disease or chronic use of medications. The visual acuity was 20/20 and the fundus was normal in all affected students. Of the 93 cases of defective color vision in males (8.18%), 56 cases (4.93%) involved deuteranomaly, 13 (1.14%) protanomaly, 13 (1.14%) deuteranopia, and 11 (0.97%) protanopia. The four cases in females (0.43%) involved deuteranomaly in three cases (0.32%) and protanomaly in 1 case (0.11%). Deuteranopia and protanopia were not detected in females. CONCLUSION: This is the first study to determine the prevalence of congenital color blindness in Iran. The results agree with reports of prevalence of congenital color blindness from Western Europe.
Adolescent↗
[Color vision in glaucoma].
This article is a general view of evaluated acquired color vision defects in the early stages of primary glaucoma and in patients at risk for glaucoma. The articles published until now indicates a decrease in color discriminating sensitivity in the short wavelength part of the visible spectrum in patients with glaucoma as well as in patients with ocular hypertension. It has been found a positive correlation between the blue-yellow color vision defects and the perimetric changes in the glaucomatous eyes. Blue-yellow color vision testing with the anomaloscope may serve as an additional test in the early diagnosis of glaucoma but the absence of dyschromatopsia does not exclude the disease.
Color Perception↗
Color vision in diabetic school children.
The color vision of 64 diabetic school children was studied. Acquired color vision defects due to diabetes could not be found in any of the children. Two of the children had a congenital red-green color vision defect. In the examination, three different pseudoisochromatic plate tests (Isihara, Standard Pseudoisochromatic Plates part 2, and Lanthony Tritan Album) were used as well as the Nagel anomaloscope and three different cap arrangement tests (Panel D 15, Lanthony Desaturated Panel, and Farnsworth-Munsell 100 hue). The plate tests and the anomaloscope examination were fast, reliable, and well accepted by the children. The cap arrangement tests took more time, and many of the children neither liked nor properly performed these tests. Twelve color dependent glucose strip tests for diabetes care at home were also studied. A few of the youngest school children made mistakes in interpreting the colors of these strips, although their color vision was normal.
Adolescent↗
Acquired dyschromatopsia in combined exposure to solvents and alcohol.
HYPOTHESIS: Does occupational exposure to solvents in combination with alcohol intake give rise to acquired color vision defects? METHOD: A total of 138 individuals exposed to solvents (toluene, xylene, trichloroethylene, tetrachloroethylene) were examined using Lanthony's D-15 test and compared with 100 nonexposed controls. The extent of color vision loss was quantitatively assessed based on Bowman's color confusion index (CCI). A cumulative exposure index was calculated from the hours of exposure per day and the years of exposure. In 30 persons who were exposed to trichloroethylene and tetrachloroethylene, urinary trichloroacetic acid was assessed as a parameter of exposure. Alcohol intake was calculated as based on interviews of patients in grams of ethyl alcohol per week. RESULTS: Individuals who consumed more than 250 g alcohol/week and were simultaneously exposed to solvents showed a significantly elevated CCI (P = 0.0044). No significant correlation emerged between trichloroacetic acid excretion in the urine or the cumulative exposure index and the CCI. CONCLUSION: The combination of alcohol intake and occupational exposure to solvents discloses the risk of acquired subclinical color vision defects.
Adult↗
Classification of Farnsworth-Munsell 100-hue test results in the early treatment diabetic retinopathy study.
PURPOSE: To classify and describe clinically meaningful classes of color vision defects using pretreatment Farnsworth-Munsell 100-hue results from the Early Treatment Diabetic Retinopathy Study (ETDRS) patients using standard statistical techniques. DESIGN: The ETDRS was a randomized trial investigating retinal photocoagulation and oral aspirin in diabetic retinopathy. METHODS: Farnsworth-Munsell (FM) 100-hue test was successfully administered before initiation of study treatment in each eye of 2701 of the 3711 ETDRS patients. Test results were converted into a Fourier series, classified by cluster analysis in the deferred-treatment group of eyes, and verified in the immediate-treatment group of eyes as separate samples. RESULTS: Cluster analysis uncovered thirteen distinct patterns. Pattern A (51% or 1366 of the eyes) showed unimpaired hue discrimination and was comprised of younger patients with no or little macular edema. Pattern B eyes (10% or 262) showed generalized impairment of hue discrimination with no main axis defect. Patterns C (C1, C2, C3), comprising 26% (or 698) of the eyes, showed increasing severity of the yellow-blue diabetic retinopathy defect, associated with increasing mean age and increasing macular edema severity. Patterns D (D1, D2), comprising 6% (or 164) of the eyes, were similar to the C patterns but showed a stronger yellow-blue defect. Patterns E (E1, E2, E3), or approximately 2% (or 38) of the eyes and predominantly male, exhibited the expected pattern for congenital protan defect. Patterns F, G, and H, approximately 6% (or 153) of the eyes, showed distinct patterns of one-sided axes. The nomenclature is arbitrary. CONCLUSIONS: Cluster analysis of FM 100-hue test results has found 13 patterns of impaired hue discrimination, helpful in understanding color vision defects in diabetes mellitus.
Adult↗
[Clinical advantages of colorimetric exploration in the early diagnosis of glaucomatous neuropathy].
AIM: The purpose of this investigation was to evaluate acquired color vision defects in the early stages of primary glaucoma and in patients at risk for glaucoma. MATERIAL AND METHODS: Patients with primary open-angle glaucoma, normal-tension glaucoma and ocular hypertension were examined with the IF-2 anomaloscope. The Rayleigh equation and the Moreland equation were tested. We studied the relationships between color vision defects and the other tested variables. RESULTS: We found the mean value of the setting range of the Moreland equation significantly increased in all tested groups. Color vision disturbances were found in 57% of eyes with glaucoma and in 31% of eyes with ocular hypertension. We found a positive correlation between the blue-green colour vision defects and the perimetric changes in the glaucomatous eyes. These results indicate a decrease in color discriminating sensitivity in the short wavelength part of the visible spectrum in patients with glaucoma as well as in patients with ocular hypertension. CONCLUSION: Blue-yellow color vision testing with the anomaloscope may serve as an additional test in the early diagnosis of glaucoma but the absence of dyschromatopsia does not exclude the disease.
Adult↗
[Representation of normal and pathologic macular color vision].
INTRODUCTION: The computerized chromatic test allows a graphic visualization of the colors perceived by normal and pathologic retina. MATERIAL AND METHOD: This test was returned by an album (six series of plates with ten levels of saturation), a lamp and a program for graphic representation. RESULTS: The graphic image was returned by the computer. For a normal eye, the aspect of the chart was a set of ten concentric saturation levels: the most saturated circle were located on the outside. For an acquired or congenital dyschromatopsia, the limits of the neutral zone are located in the center and are constituted by the most saturated level of blind charts of the album. DISCUSSION AND CONCLUSION: The informatized chromatic test is a very easy one to appreciate color vision defects.
Color Perception Tests↗