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By testing individuals as well as a group seasonal oscillations of the Anomaloscope's mixing screw regulation could be observed. For that reason further standardization of research methods is requested.
There are many advantages to the computerization of colour vision tests. However, previous computerized colour vision tests have involved equipment and methods not commonly used in clinical practice. We created computer emulations of the City University Colour Vision Test (CUT), Ishihara plates and American Optical Hardy-Rand-Rittler (AO-HRR) plates using a commonly available 24-bit colour Macintosh computer. Our colour monitor was calibrated to standard display white (D65), and colour plates were imaged with a colour scanner. The computerized colour images were compared with the standard test plates in a sample of 21 subjects with normal colour vision, 10 patients with congenital red-green defect and 1 patient with an acquired mixed colour defect. The computer images of the three tests correlated well with their conventional counterparts on kappa statistic analysis (p < 0.001), for both the colour normal and colour defective groups. We conclude that our computer emulations of the CUT, Ishihara and AO-HRR tests screen subjects with normal colour vision with high specificity and delineate congenital colour defects with a sensitivity comparable to that of their conventional counterparts.
Air traffic controllers perform a number of tasks which involve color identification, color discrimination, and color naming. Normal color vision is required for air traffic controllers, although the requirement is currently under review. The most critical task involving color is the distinction of red and black on flight strips; the distinction must be made reliably, quickly, and routinely for flight safety. In this study of four protanopes and three normals, all the protanopes were unable to make this distinction reliably under the lighting levels encountered at air traffic control (ATC) centers, whereas none of the normals had any difficulty. Protanopes also made numerous errors with other ATC tasks involving color. The use of a red filter, often recommended to aid color defectives, actually made performance worse and additionally compounded the usual protanopic loss of brightness for red light. When Snellen visual acuity was tested using the red filters, protanopes needed up to four times larger letters than the color normals. It is concluded that protanopes have inadequate vision for safe performance of some current ATC tasks.
A field study was conducted among 21 male workers exposed to styrene of concentration below 30 ppm in a fiber-reinforced plastic boat manufacturing plant. Twenty-one male workers with similar age groupings, years of education, and social and occupational state served as referents. The mean end-of-shift urinary mandelic acid (MA) and phenylglycoxylic acid (PGA) for the exposed workers were 84 mg/g creatinine and 66 mg/g creatinine, respectively. The Lanthony D-15 Hue Desaturated Panel was used to evaluate color discrimination of the exposed and referent groups. The results of the test were expressed as total color difference score (TCDS). The exposed workers' mean TCDS (a higher score denotes poorer color discrimination ability) was significantly (p < 0.0006) higher than the referents'. Neurobehavioral tests were also conducted, using the World Health Organization's Neurobehavioral Core Test Battery (NCTB). All the results of the NCTB were poorer for the exposed than for the referents. However, significant differences were observed only for Digit Span, Digit Symbol, and Benton Visual Retention tests. These results suggest that low exposure to styrene could affect some psychometric performance and may impair color vision.
The slow progression of diabetic retinopathy makes it difficult to assess the effects of intervention therapy. There is thus a need for surrogate markers of visual change in diabetes. Colour vision tests and electroretinography (ERG) may be useful in this regard; yet little is known of their relative performance in the assessment of visual dysfunction in diabetes. The aim of the present study was to compare colour discrimination (100 hue test) and ERG indices (oscillatory potentials (OP) and pattern ERG (PERG)) in the evaluation of aretinopathic IDDM patients. Colour discrimination was abnormal in 10 aretinopathic IDDM patients when compared with nine age matched controls; mean square root 100 hue error scores were 10.38 (SD 2.89) versus 4.77 (1.87) respectively, p < 0.01. OP implicit times of the ERG were also abnormal; for example, for right eye, mean OP1 implicit time for diabetics versus OP1 implicit time for controls was 20.1 (2.0) versus 18.6 (1.4) ms, p = 0.03. Comparison of the two techniques suggested that the 100 hue test was more sensitive and more specific than ERG OP implicit times in the detection of diabetic visual dysfunction in these patients.
In some cases, visual field screening must be greatly simplified in order to obtain clinically useful information. This becomes possible when specific techniques are used for anomalies such as relative central scotoma, hemianopsia, and glaucomatous field defects. A working knowledge of visual pathway anatomy and function enables the optometrist to efficiently screen for these disorders by confrontation with red test objects, with pseudoisochromatic plates, and with the tangent screen. After the type of field defect has been determined by initial screening, recording its parameters with the tangent screen follows easily.
Glaucomatous optic nerve atrophy is associated with morphological and psychophysical changes. Using Roth's Besancon anomalometer, the Farnsworth 100 hue test and Nagel's anomaloscope, we examined color vision in 86 eyes of 51 patients suffering from chronic open-angle glaucoma and 57 eyes of 41 normal subjects. In the normal control group, blue und green sensitivity decreased and, accordingly, the anomaly quotient tested with Nagel's anomaloscope increased significantly (p less than 0.00001) with age. If the glaucoma and control groups were matched for age, refractive error and central visual acuity, decreasing blue sensitivity significantly (p less than 0.05) correlated with diminished visibility of the retinal nerve fiber bundles, a higher morphological glaucoma stage and larger perimetric defects. The presence and depth of localized defects of the retinal nerve fiber layer were not significantly different in glaucoma subgroups with lower and higher blue sensitivity, respectively, when the subgroups were matched for age, refractive error and visual acuity. No papillomorphologic marker for the cyanodyschromatopsia was detected. Red-green color vision was not significantly different between the normal and glaucoma eyes. Testing of blue color vision as an additional method is useful in the differential diagnosis of beginning glaucomatous optic nerve damage in patients with clear optic media and lack of macular changes.
A new color vision test distinguishes patients with X-chromosome-linked blue cone monochromatism from those with autosomal recessive rod monochromatism. The test consists of two instructional and four test plates. Each test plate has three identical blue-green arrows and one purple-blue arrow; test plates differ from one another only with respect to the chroma of the purple-blue arrow. All five patients with blue cone monochromatism, aged 5 to 31 years, easily distinguished the purple-blue arrow on all four test plates, whereas none of the seven patients with rod monochromatism, aged 6 to 60 years, could distinguish the purple-blue arrow on all four plates. If a boy has a reduced visual acuity, normal rod electroretinograms, and 30-Hz cone electroretinograms reduced more than 97% below normal, this test can be used to determine whether his condition is an X-chromosome-linked one or an autosomal recessive one.
Results of several previous reports have questioned the occurrence of the tritan color deficiency independently of dominantly inherited optic atrophy. This report describes the results of testing 34 members of a pedigree (including four tritans) for whom optic atrophy can be ruled out according to criteria previously described by Krill et al.
As an exploratory study six colour vision tests were given to nine male and two female achromats from the Shankhabanik community in Bishnupur, and to two additional similar males. All thirteen subjects had severe photophobia, fixation nystagmus, extreme weakness of vision (4/24 to 3/60) and the red end of the spectrum was much shortened. This research indicates that they had a form of incomplete achromatopsia, varying from an almost complete to a very severe partial loss of colour vision. The condition is inherited as an autosomal recessive. The most likely interpretation of these cases is that they are incomplete rod achromats. Their performance on the colour vision tests is tabulated, and shows complete inability to do the Ishihara test; nearly complete inability on the HRR test, with a possible slight tendency to do better in the yellow-blue than the red-green sub-tests; on Sloan's test they show approximate accordance with her results for achromats; they have severe difficulty with the dichotomous and 100-hue tests, with a possible slight tendency to make fewer errors on the G/B sections. The anomaloscope shows little abnormality of mid-matching points, but great increases in average matching ranges above the normal, although not absolute loss of colour sense, but with extreme darkening or shortening of the red end of the spectrum. Their colour naming was carefully recorded, and was fairly good occasionally, sometimes erroneous without being wildly at fault, and most often completely wrong. The records of colour naming were made, not, of course, as a form of colour vision test, but simply to illustrate the ways in which such defectives make an effort to use colour names in general use among their friends and relatives.
Three hundred patients who have congenital colour vision deficiencies were examined at the author's eye clinic for 3 years (1987-1990) using 5 types of colour vision tests: Hahn's, TMC's, Okuma's (new), H-R-R's colour vision tests and Double 15 Hue Test (Hahn). The results obtained from each test were quite different in type and grade, and the summarized results were considered to be the best: Type: protan 23.3%, deutan 76.0%, unclassified 0.7% Grade: mild 20.3%, medium 25.3%, strong 54.4% The frequency of coincidence both in type and grade between the summarized results and those of each test were compared, and the highest was 62.3% in Double 15 Hue Test. The efficiency of the author's colour vision test and Double 15 Hue Test were evaluated with the data in this clinical trial, and they were found to be useful for classifying the type and estimating the grade of the congenital and also acquired colour vision deficiencies.
The results of pseudoisochromatic tests (TMC Ishihara, AOH-R-R) are relatively independent of age. In the Panel D-15, the NCT box 6/4 and the desaturated panel, ageing goes hand in hand with blue-yellow confusions. Fault-positive red-green confusions result from D8/2 examination. For the FM 100 Hue test and the Anomaloscope Nagel, the data found in the literature are confirmed. In nuclear cataract there is no increased shift of the Rayleigh equation towards the green, but towards the red.
A new sorting test requires only two minutes for quantitative estimation of saturation thresholds for bluish pigment colors. The test is highly sensitive to and specific for differences between normal subjects and individuals with acquired color vision defects. When combined with Ishihara's pseudo-isochromatic plates, it discriminates between congenital and acquired dyschromatopsias and identifies subjects with combined defects.
We gave the Farnsworth-Munsell 100-hue color vision test to 232 normal subjects between 10 and 80 years of age. One half the subjects underwent binocular testing followed by monocular testing. In the other half monocular testing preceded binocular testing. Performance was better with both eyes than with either eye alone. The worst performance occurred on monocular tests in subjects without previous experience with the task (that is, those for whom this was the first test). The well-known age trend was apparent (children and elderly have the worst color vision). New data are provided for judging the point at which the total error score may be considered pathologic.
Vision screening tests within the limits of industrial medicine examinations, together with physical examinations, were done on human individuals by means of pseudo-isochromatic charts in order to detect "red-green blindness". The tests were carried out on 1589 individuals (males and females) from 10 medium-scale plants of the Saarbrücken area (Federal Republic of Germany). The results obtained from male individuals by 919 Ishihara-tests were only considered, categorized and graphically represented according to their age groups. The data have been collected from the cases examined mostly between the years 1976 to 1977. About 1500 cases were examined per year. Because the samples were not selected at random, one has to be cautious with regard to the statistical interpretations of the results. However, due to the large number of cases included in the study, it can be statistically represented. The histogram illustrating the distribution of colour-vision deficiency, according to each age group, shows the highest peak at an age range of 30 to 35 years. This indicates that a considerable number of cases with colour-vision deficiency was discovered late. The individuals have to be early examined by school physicians, house physicians, occupational physicians, internists or ophthalmologists with this colour-vision screening test, before they enter professional life. Some symptomatical complexes of internal diseases and human genetics, i.e. related to "colour-vision blindness" are also emphasized hemophilia and hemolytic anemia due to glucose-6-phosphate dehydrogenase deficiency.
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.
Six cases of classic achromatopsia are presented. The methods of practical clinical diagnosis are discussed, including paradoxical pupillary constriction in darkness, the easily performed Sloan achromatopsia test, and electrophysiologic studies which are useful in young children. The visual and cosmetic benefits of heavily tinted contact lenses in such patients are stressed.
Defective temporal integration for a foveally fixated 100' of arc red (660 nm) Btest flash presented on a 30 cd/m2 yellow ( Schott , OG 530) background was measured in subjects with deuteranopia , as well as in subjects with anomalous trichromacy of the deutan type. The mean integration time was 77 +/- 17 ms in 12 normal subjects but only 35 +/- 6, 46 +/- 11 Band 41 +/- 15 ms in respectively 6 subjects with deuteranopia , 7 with extreme deuteranomaly Band 9 with deuteranomaly . An increase in the test duration from 10 to 200 ms increased the mean relative sensitivity by 0.85 +/- 13 log units in the normal subjects compared with 0.45 +/- 0.05, 0.57 +/- 12 and 0.56 +/- 19 in subjects with deuteranopia , extreme deuteranomaly and deuteranomaly .