Tritan defects found by using Velhagen's pseudoisochromatic plates (24th edition).
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Adult↗
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Results for “Color Vision Defects”
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[Monochromatic ERG responses in congenital color perception defects. Spectral characteristics with selective chromatic adaptations].
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Adaptation, Ocular↗
Validity of the Holmes-Wright lantern as a color vision test for the rail industry.
A simulated field test was designed to determine whether the Holmes-Wright A lantern (HWA) is a valid color vision test for the rail industry. The simulation replicated viewing rail signal lights at 0.8 km distance under daylight conditions. Using the worst-normal as the maximum number of allowable errors on the simulation, 94% of the color-defectives failed both tests on the first trial and 92% failed at the second session. The HWA had a higher false negative rate than a false alarm rate. The majority of individuals who had discrepancies on the two tests were mild deutans. Results from the Ishihara test were marginally better at predicting performance on the simulation.
Color Perception Tests↗
Anomaloscope examination: scotopization (the luminance fall).
PURPOSE: The evaluation of a criterion for the detection of pathologic scotopization in routine anomaloscope examination. METHODS: Fifty congenital protan subjects, 50 congenital deutan subjects, 30 autosomal recessive congenital achromats, and 25 (44 eyes) acquired type I red-green defective subjects were selected. The anomaloscope examination was according to the Linksz procedure. The luminance fall was calculated as the slope quotient SQ: Y units luminance fall per X units width of the matching range. RESULTS: The mean SQ was -0.01 for congenital deutan subjects, -0.40 for congenital protan subjects and -1.30 for congenital achromats. There was no overlap between the three groups. Pathologic scotopization was found in 98% of the eyes presenting with an acquired type I colour vision defect. CONCLUSION: Calculation of the slope quotient SQ is helpful for the detection of pathologic scotopization in acquired colour vision deficiency.
Color Vision Defects↗
Polymorphisms of red-green vision in some populations of Southern Africa.
Some 5,000 schoolboys of the Khoikhoi, Negro, "Coloured," and Malay populations were screened with the Ishihara plates, and those with defective red-green vision were diagnosed with an anomaloscope. The findings are presented in terms of the six protan and deutan mutant alleles, a few large population-samples (e.g., Nama and Zulu) being characterized by absence of the allele for protanopia. The overall frequencies of mutants range from less than 1% to over 4%. No correspondence was found between these data and linguistic affinities of eight Bantu-speaking groups, nor between the frequencies of colorblindness and previously estimated proportions of San genes in these eight populations; on the other hand, a north-south cline of increasing frequences of mutants and of dichromacies among the Bantu-speakers was noted. The overall frequency of defective red-green vision among Cape Coloureds, 3.3%, is compatible with previously estimated racial composition of this population. The Malay sample is characterized by the highest frequency of protan mutants (2%), a 1:1 protan-deutan ratio, and an overall frequency of 4% of red-green defects. The study illustrates the potential value of anomaloscopic characterization of colorblindness in attempts to evaluate human evolutionary processes.
Adolescent↗
Visual mechanisms for the analysis of spatial pattern.
After a brief outline of the structure and electrophysiology of the normal visual pathways, the responses, as revealed by psychophysical studies, of the visual system to spatially and temporally varying stimuli are reviewed. An appropriate network model, involving two sequentially organized classes of visual channel, is presented. Examples are given in which the psychophysical methods developed to analyse the normal visual pathways are applied to cases in which these pathways are defective (amblyopia, albinism, hemianopia, parietal cortical lesion, inhibitory central colour vision defect). These cases not only illustrate the value of psychophysical techniques in analysing disturbances of visual function but are also suggestive of the mechanisms involved in higher processing of the retinal image.
Adolescent↗
Spectrally selective flash early receptor potential (ERP) in dichromats.
The human spectrally selective flash early receptor potential (ERP) was studied in 12 dichromats: 6 protanopes (12 eyes) and 6 deuteranopes (12 eyes). Color filters used were Kodak Wratten filters No.23A, No.57, and No.47 for the red, green, and blue flash ERPs, respectively. The ERP amplitude was measured between the summits of R1 and R2. Mean amplitudes of the red flash ERP and green flash ERP were highly significantly decreased in the protanopes (p less than 0.001) and deuteranopes (p less than 0.01) as compared with the corresponding data in 10 normal subjects (20 eyes). The mean amplitude of the blue flash ERP was significantly lower than normal (p less than 0.001) in the deuteranopes. The mean ratio of the blue flash ERP amplitude to the red flash ERP amplitude showed a highly significant increase in the protanopes (p less than 0.001) and a highly significant decrease in the deutoranopes (p less than 0.001) compared with the mean ratio in the normal subjects, indicating a new, useful index for the objective clinical detection of congenital color defects.
Adolescent↗
[Multiple evanescent white dot syndrome].
A 38-year-old male patient experienced a unilateral visual acuity decrease to 20/60 and showed white dots at the level of the retinal pigment epithelial interface characteristic of multiple evanescent white dot-syndrome. Fluorescein angiography demonstrated early hyperfluorescent defects and some late staining. In spite of improvement of the visual acuity and the alterations of the fundus, an enlargement of the blind spot and some sharply demarcated depigmentations of the retinal pigment epithelium remain. This case shows, that already at the beginning of symptoms the characteristic white dots may be present. Enlargement of the blind spot and depigmentations of the retinal pigment epithelium may remain as defects after multiple evanescent white dot-syndrome.
Adult↗
[A NEW EYE SYNDROME WITH X-CHROMOSOMAL TRANSMISSION. A FAMILY CLAN WITH FUNDUS ALBINISM, FOVEA HYPOPLASIA, NYSTAGMUS, MYOPIA, ASTIGMATISM AND DYSCHROMATOPSIA].
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Albinism↗
[Determining a standard for the diagnosis of blue-yellow defects in the F-M 100 hue test].
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Color Perception Tests↗
[Determining a standard for the diagnosis of red-green defects in the F-M 100 hue test].
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Color Perception Tests↗
Influence of pathologic scotopization on the extended Rayleigh match.
Pathologic scotopization, an important symptom of retinal disease, can be studied by means of the Nagel II anomaloscope. This method is called the micro-screw method. The micro-screw method was performed in 14 congenital and 13 acquired colour vision defective individuals. The method proves to be useful in detecting symptoms of rod intrusion in colour vision under photopic conditions.
Color Perception Tests↗
Spectral sensitivities of acquired color defects analyzed in terms of color opponent theory.
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Amblyopia↗
Colour vision defects in asymptomatic carriers of the Leber's hereditary optic neuropathy (LHON) mtDNA 11778 mutation from a large Brazilian LHON pedigree: a case-control study.
AIMS: To determine if asymptomatic carriers from a previously identified large pedigree of the Leber's hereditary optic neuropathy (LHON) 11778 mtDNA mutation have colour vision deficits. METHODS: As part of a comprehensive analysis of over 200 members of a large Brazilian LHON pedigree spanning seven generations, colour vision tests were obtained from 91 members. Colour vision was tested one eye at a time using the Farnsworth-Munsell 100 (FM-100) hue colour vision test. The test was administered under uniform conditions, taking into account: ambient light levels, daylight colour temperature of 6700 kelvin, and neutral uniform background. Tests were scored using the FM-100 MS-Excel computer scoring program. Defects were determined and categorised as tritan, deutan, or protan. Categorisation of each dyschromatopsia was based on review of demonstrated axis computer generated plots and age adjusted error scores which coincided with Verriest 95% confidence intervals. Only the axis with the greatest magnitude error score was used to classify the defect. 55 of the 91 test subjects were LHON mtDNA 11778 J haplotype mutation carriers, proved by mtDNA analysis. The remaining 36 subjects were age matched non-blood relatives (off pedigree), who served as controls. RESULTS: 27 of 55 carriers (49.10%) were shown to have colour vision defects in one or both eyes. 13 of the 27 (48%) abnormal tests in the carrier group were tritan defects and the remaining 14 (52%) were deutan defects. Nine of the 27 (33%) abnormals in the carrier group were identified as having bilateral defects. Six of these were deutan, and the remaining three were tritan dyschromatopsias. Only six of the 36 (16.66%) age matched controls were found to have any type of dyschromatopsia. Five (83.3%) of these were deutan defects. The remaining one was a tritan defect. The difference between the two groups using a chi(2) test with one degree of freedom was statistically significant with a p value less that 0.001. CONCLUSIONS: Until now, LHON has always been characterised by a sudden, devastating vision loss. Asymptomatic carriers, those without vision loss, were considered unaffected by the disease. It now appears that asymptomatic carriers of the LHON mutation are affected by colour vision defects and may manifest other subtle, yet chronic, changes.
Brazil↗
An analysis of colour vision in 10,000 patients.
Examination of a great number of patients resulted in the depth localisation theory. The combination of this theory with the fixation-eccentrisation theory is clinically useful: acquired colour vision defects can be subdivided by the fixation mode and by signs of receptor damage. There are indications that in multiple sclerosis the slowly progressive cases present with more receptor damage than the acute cases.
Adolescent↗
Color matching and Stiles-Crawford effect in central serous choroidopathy.
Color matching and Stiles-Crawford effect measurement were performed in 3 patients with central serous choroidopathy, 2 normal and 1 deuteranomalous trichromats. The color matches in the affected eye of each patient were displaced to red and could be explained by the hypothesis that the visual photopigments are in reduced optical density due to receptor disorientation caused by serous elevation of the sensory retina. The Stiles-Crawford effects of the affected eyes was abnormal confirming the hypothesis of receptor disorientation. The type III color defect accompanied by pseudo-protanomaly ascribable to receptor disorientation as occurs in central serous choroidopathy may be differentiated from the type III defect without pseudo-protanomaly.
Absorption↗
Evaluation of an updated HRR color vision test.
The HRR pseudoisochromatic plate (pip) test was originally designed as a screening and diagnostic test for color vision deficiencies. The original HRR test is now long out of print. We evaluate here the new 4th edition of the HRR test, produced in 2002 by Richmond Products. The 2002 edition was compared to the original 1955 edition for a group of subjects with normal color vision and a group who had been previously diagnosed as having color vision deficiencies. The color deficient subjects spanned the range of severity among people with red-green deficiencies except for one individual who had a mild congenital tritan deficiency. The new test compared favorably with the original and in at least two areas, outperformed it. Among subjects with deutan defects the classification of severity correlated better with the anomaloscope results than the original; all the subjects who were classified as dichromats on the anomaloscope were rated as "severe" on the new HRR, while those diagnosed as anomalous trichromats were rated as mild or medium on the new test. Among those with moderate and severe defects the new test was highly accurate in correctly categorizing subjects as protan or deutan. In addition, a mild tritan subject made a tritan error on the new test whereas he was misdiagnosed as normal on the original.
Adult↗