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Results for “Color Vision Defects”

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PubMed1990

Color vision characteristics of visually impaired children.

A classroom assessment of color vision characteristics of children with low vision was conducted using a battery of tests. The results showed 75% of the children failed one or more tests, although only 24% had a moderate or severe color vision defect. Comparisons with the low vision clinic color vision assessment showed that many of the children were not identified as being color vision defective. Considering the use of color-coded information in education, greater emphasis on color vision evaluations in routine low vision examinations is recommended.

Child↗

PubMed1988

Performance of the standard pseudoisochromatic plate test.

The Standard pseudoisochromatic Plate (SPP) test was administered to 346 normals, 55 anomalous trichromats, and 46 dichromats. Its ability to detect and classify congenital color defectives was assessed. The performance of each plate was assessed separately and compared with its colorimetric properties. The test as a whole achieves a high level of accuracy in separating normals from color vision defectives [Youden's Index (YI) = 92.4%] and a high reliability (71.3%) in classification of the congenital color vision defectives. The performance of individual plates in separating color normals and color vision defectives of individual plates varies (YI ranges from 69.8 to 86.1%). A set of three plates can be chosen, which achieves a performance similar to that of the whole test. The test is found to be a reliable clinical screening method for congenital red-green color vision defectives.

Color Perception Tests↗

PubMed1975

Predictive validities of several clinical color vision tests for aviation signal light gun performance.

Scores on the American Optical Company (AOC) test (1965 edition), Dvorine test, Farnsworth Lantern test, Color Threshold Tester, Farnsworth-Munsell 100-Hue test, Farnsworth Panel D-15 test, and Schmidt-Haensch Anomaloscope were obtained from 137 men with color-defective vision and 128 men with normal color vision. The validity of each of these tests in predicting scores on the aviation signal light gun was assessed by using daytime and nighttime administrations of the light gun as the criteria. Two "best sets" of plates from the AOC and Dvorine tests were selected by calculating a multiple regression equation in a stepwise manner with the nighttime and then the daytime administration of the signal light gun test as the criteria. Based on a graphic presentation of the miss and false alarm rates for each test at various possible cut scores, suggestions were made regarding the use of each test and the selection of optimal pass/fail scores.

Aerospace Medicine↗

PubMed1990

Molecular genetics of X chromosome-linked color vision among populations of African and Japanese ancestry: high frequency of a shortened red pigment gene among Afro-Americans.

Red-green color vision in humans is mediated by the X chromosome-linked highly homologous red and green pigment genes. Color vision defects are caused by deletions and fusions involving these genes. However, we found the frequency of molecular abnormalities among Caucasians to be twice as high as that of phenotypic color vision defects. Among Japanese the frequency of phenotypic and molecular color vision defects was similar (approximately 5%). Among Afro-Americans, molecular defects (largely green-red fusion genes) were at least five times more frequent (21%) than phenotypic color vision defects (approximately 4%). In addition, 35% of Afro-Americans, 2% of Japanese, and less than 1% of Caucasians had a shortened red pigment gene not associated with phenotypic color vision defects. This gene lacked 1.9 kilobases in its first intron and had the identical size as the green pigment gene from which it presumably originated by gene conversion in an ancestral African population. This gene and the closely linked glucose-6-phosphate dehydrogenase A+ variant were in linkage equilibrium. A model for the evolutionary origin of the color vision pigment genes in higher primates is portrayed.

Black People↗

PubMed1992

Selective expression of human X chromosome-linked green opsin genes.

The human red and green photopigments are specified by genes on the long arm of the X chromosome (Xq28). In individuals with normal color vision, the locus was proposed to consist of a single red pigment gene upstream of one or more copies of green pigment genes. The presence of a single red pigment gene in the array was confirmed by demonstration of only one retinal mRNA transcript coding for the red opsin. In individuals with multiple green pigment genes, it is unknown whether all genes are expressed. We analyzed the sequence of red- and green-specific mRNA from retinas of individuals with multiple green pigment genes in comparison with the corresponding genomic DNA sequences. The data showed that only a single green pigment gene is expressed. We therefore suggest that a locus control-like element, already known to be located 3.8 kilobases upstream of the transcription initiation site of the red pigment gene, allows transcription of only a single copy of the green pigment genes, probably the most proximal copy. This finding provides an explanation for the not-infrequent presence of 5' green-red hybrid genes in individuals with normal color vision. Such hybrid genes are usually associated with defective color vision. We suggest that 5' green-red hybrid genes produce defective color vision only when their position in the gene array allows expression in the retinal cone cells.

Alleles↗

PubMed1985

Standard Pseudoisochromatic Plates part 2.

The Standard Pseudoisochromatic Plates part 2 are able to detect acquired blue-yellow color vision defects as well as acquired and congenital red-green color vision defects. One test plate might be age dependent. The value of 3 test plates is not clear.

Adolescent↗

PubMed1989

Note on color preference and color vision test performance.

The incidence of color deficient vision was investigated using the Pseudo-Isochromatic Plates on a relatively large and representative group. In the sample of 112 adults aged 20 to 80 yr. and comprised of 53% women and 12% minorities, 8% of men and 3% of women were color deficient. Over-all performance indicated no effects for sex or race. Nearly half of the plates were nondiscriminating among sex, minority/majority, and "normal" and "defective" color vision groups. Named color preferences within the "normal" group strongly favored blues and reflected no sex differences.

Adult↗

PubMed1988

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↗

PubMed1991

[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↗

PubMed1992

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↗

PubMedDate not supplied

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↗

PubMed1990

Normative data for the standard pseudoisochromatic plates--Part 2.

The Standard Pseudoisochromatic Plates--Part 2 are designed as a screening test for acquired color vision deficiencies. In order to control for age-related changes in color vision, it is necessary to establish norms for this test. Results from this study suggest that, disregarding one figure on the first test plate, one or more blue-yellow errors indicate a blue-yellow color vision defect for patients between 20 and 60 years, whereas two or more blue-yellow errors are indicative of a blue-yellow color vision defect for patients under 20 years and over 60 years. For modified red-green test figures, one or more errors are suggestive of a red-green defect for patients under 60 years, whereas two or more errors indicate red-green vision defect for patients over 60 years. Asking patients to judge which figure is more distinct on each test plate is not useful in comparing responses between patients.

Adolescent↗

PubMed1988

[Evaluation of the central visual field by the Friedmann Mark I analyzer and color vision in 85 patients with multiple sclerosis. Correlation with visual evoked potentials in 50 cases].

Analysis of the visual field using Friedmann's analyser Mark I and color study in 85 multiple sclerosis patients. Static perimetry of the central visual field and test batteries (Ishihara plates, 15 Hue Standard, 15 Hue of Lanthony) for acquired color vision defects were performed in 85 multiple sclerosis patients (61 definite, 12 probable, 12 possible cases). Results in patients were compared to data obtained in 53 control subjects matched for age. 64% of the 85 patients and 52% of 48 patients with no history of optic nevritis showed visual field abnormalities and/or color vision defects. Comparison with VEP was available in 50 patients. While 10 patients had abnormal VEP and normal static perimetry and coloration tests, 5 patients had the reverse findings.

Adolescent↗

PubMed1985

Improved color test results with large-field viewing in dichromats.

Standard methods for screening color vision defects may be expected to underestimate a color defective's complete chromatic discrimination abilities because the viewing field is confined to the fovea (central 2 degrees). Large-field (8 degrees) Farnsworth-Munsell 100-hue and dichotomous (D-15) tests were constructed. The 100-hue test, along with its small-field counterpart, was administered to five deuteranopes (green defectives) and four protanopes (red defectives). The D-15 small- and large-field tests were given to these same subjects with the addition of two deuteranopes and one protanope. Both deuteranopes and protanopes showed marked improvement on the large-field D-15 and 100-hue tests. This improvement in performance for large-field over small-field viewing is consistent with color-matching data, which show large-field trichromacy in observers who have been demonstrated to be small-field red-green dichromats. These results suggest that tests confined to central fovea viewing provide an incomplete functional description of the color vision of an appreciable number of classic dichromats.

Color Perception↗

PubMed1991

[The Nagel anomaloscope in the diagnosis of eye diseases].

The Nagel anomaloscope can be incorporated in the diagnosis of eye diseases. Three parameters are relevant: 1. The measure of the absolute matching range (scale units) 2. The preferred direction of the widened matching range (to red or to green) 3. The luminance matches with the yellow (decreasing matches indicating a pathologic scotopisation). - Six pathologic anomaloscope findings can be differentiated: 1. Pseudoprotanomaly (retinal diseases; type III acquired blue-yellow defects) 2. Symmetrically widened absolute matching range (reduced hue discrimination without reference to its etiopathology) 3. Absolute matching range asymmetrically widened to red with scotopisation (retinal diseases; type III acquired blue-yellow defects or type I acquired red-green defects) or without scotopisation (retinal diseases or optic nerve diseases; type III acquired blue-yellow defects) 4. Absolute matching range asymmetrically widened to green (mostly optic nerve diseases; type II acquired red-green defects) 5. Acceptance of both end matches ("0" up to "73") with scotopisation (retinal diseases) or without scotopisation (optic nerve diseases) 6. Achromatic matches (selective cone diseases, such as Stargardt's dystrophy or progressive cone dystrophy). Indications for anomaloscope examinations and clinical application of the method are discussed in ten cases. The utility of the Rayleigh-equation consists in diagnosing pathologic scotopisation (differential diagnosis between retinal diseases and optic nerve diseases) and in making a quantitative evaluation of the acquired color vision defect (follow-up examination).

Color Perception Tests↗

PubMedDate not supplied

Color vision screening of young children.

Early detection of congenital color vision defects is desirable, but school screening studies have been stymied by lack of a suitable test. We evaluated a new color vision test, the APT-5, for use by volunteer screeners in schools and preschools. The screeners tested 1794 children, ages 3 to 13 years, and found the APT-5 easy to use with young children ages 5 years and up. Children who failed the screening were recruited for diagnostic color vision testing; for the children ages 5 to 13 years, 56% of those who failed the screening were successfully recruited. Data analysis indicated that the false-positive rate in this age group was 1% to 2%, and that for boys in this age group the positive predictive value was 71% to 81%. Retest data indicated that most false-positives were not due to the test itself, but to other factors in the school screening situation. Two thirds of all children scored as abnormal by anomaloscopy were simple deuteranomalous, indicating that the APT-5 effectively identified even mild color defects. The results of this trial indicate that the APT-5 is suitable for school color vision screening of children ages 5 years and up.

Adolescent↗

PubMedDate not supplied

[The examination of color vision using a 2 metameric equation method].

Modern anomaloscopes with four independent light channels (i.e. Besançon-Anomalometer which was presented in 1979 at the SFO Congress) allow accurate examinations of color vision. In our routine clinical examination, we use two metameric equations: the red-green Rayleigh equation and the blue-green Moreland equation. This so called Two-Equation-Method enables the diagnosis of congenital and acquired color vision defects in a precise qualitative as well as quantitative way. For both equations the goal of the examination is to measure the absolute matching range. Abnormal color vision is diagnosed if the absolute matching range is shifted and/or enlarged in one or both of the two metameric equations. In congenital colour vision deficiencies, the results are similar to those obtained with the Nagel anomaloscop. The different types of acquired defects are compared with the types of Verriest's classification. A computer controlled clinical examination of color vision, which will make the procedure simplier and shorter for the patient is actually being developed.

Color Perception↗

PubMed1978

Autosomal recessive incomplete achromatopsia with protan luminosity function.

A unique form of dichromatic color vision is described in a family with incomplete achromatopsia. In 1966, incomplete achromatopsia was diagnosed in 4 of 14 children of a consanguineous marriage. The 4 affected had best visual acuities of 6/60 or 6/180, pendular nystagmus, and aversion to bright lights. The ERG showed minimal photopic responses. No abnormality of rod function was present. There was a severe color vision defect. In 1976, one of the patients returned for further color testing. Color tests included measurement of the luminous efficiency function using heterochromatic flicker photometry and colorimetric evaluation. The luminous efficiency function resembled that of the protanope. From the colorimetric measurements, we conclude that the patient has a unique form of dichromatic color vision mediated by two visual photopigments: the normal MWS cone photopigment and a photopigment with the spectral characteristics of rhodopsin.

Adolescent↗