Congenital Dyschromatopsia Research Articles

Evaluation of a New Test for the Diagnosis of Congenital Dyschromatopsia in Children: the Color Vision Evaluation Test

To evaluate the validity, reproducibility, and feasibility of the "Color Vision Evaluation Test" (CVET) for the diagnosis of congenital dyschromatopsia. Prospective, monocentric, sensitivity, and specificity analysis study comparing the CVET with the Farnsworth 15 Hue standard test (15 Hue STF). A total of 155 children from the Paediatric University Hospital of Nice were screened (both eyes) using Ishihara's pseudoisochromatic cards, which allowed dividing them into a dyschromatic group and a control group. All children underwent twice the 15 Hue STF and the CVET with at least 7days between both series of tests. Patients' mean age was 7.56 ± 3.51 years in the dyschromatic group and 8.92 ± 2.9 years in the control group. At the first evaluation, the sensitivity and specificity were 95.7% and 96.4%, respectively, for the CVET and 75% and 58.9%, respectively, for the 15 Hue STF (P < .001). The reproducibility of the CVET was 100%, whereas that of the 15 Hue STF was 88.4% (P= .01). The mean test explanation duration was 18.8 seconds for the CVET and 17.7 seconds for the 15 Hue STF (P= .3). In the dyschromatic group, the mean duration of the CVET was always significantly longer than that of the 15 Hue STF (P < .001). The children subjectively preferred to undergo the CVET rather than the 15 Hue STF in 84.6% of cases (P < .001). The CVET is a rapid, reliable, and reproducible test for the diagnosis of congenital dyschromatopsia. It is accessible to young children.

Névrite optique àMycoplasma pneumoniae

Optic neuritis (ON) is an inflammatory disease whose etiology remains obscure. We report a case of ON attributable to Mycoplasma pneumoniae (MP). A 26-year-old man presented a sudden onset bilateral loss of visual acuity, without any history of pulmonary or ear-nose-throat infection. Diagnosis of optic neuritis was made on the basis of visual field loss, though optic disks and visual evoked potentials were normal. Color vision could not be assessed due to a congenital dyschromatopsia. The neurological examination was normal. On magnetic resonance imaging, there was no enhancement or enlargement of optic nerves, but a demyelinating lesion of the cervical spinal cord. Lumbar puncture revealed lymphocytic meningitis with 60 white blood cells, all of them being lymphocytes. Oligoclonal bands were presents in the CSF. With no evidence of any other infection or auto-immune disease, the diagnosis of Mycoplasma pneumoniae infection was established due to the presence of Mycoplasma pneumoniae specific IgM antibodies. Outcome was quite favorable within three months without treatment. Neurological symptoms--encephalitis, meningitis, polyradiculitis, or more rarely ON or cerebella ataxia--are the main extra pulmonary manifestations of Mycoplasma pneumoniae infection. Search for anti-Mycoplasma pneumoniae IgM antibodies should be performed routinely when On is diagnosed.

Prevalence of color vision-deficient individuals among dental students

O objetivo deste estudo foi identificar indivíduos deficientes para visão de cores, testando a acuidade visual dentre um grupo de estudantes de Odontologia, e comparar o resultado obtido com os resultados encontrados na literatura, considerando o prejuízo das discromatopsias congênitas para a Odontologia, especialmente na escolha da cor dental. Foram escolhidas seis cartas determinadas dentre as cartas da seqüência do Teste de Ishihara e essas foram apresentadas como seis “slides” para 308 indivíduos, alunos de Odontologia. Durante a apresentação, o indivíduo preenchia um formulário com suas informações pessoais e a leitura da carta que estava vendo. O Teste de Ishihara é um teste de leitura de placas pseudo-isocromáticas usado para identificar indivíduos com discromatopsias congênitas; e é o mais usado dos testes para esse fim. Trezentos e oito indivíduos foram avaliados. Desses, 121 (39,3%) eram homens e 187 (60,7%) eram mulheres, com idades entre 19 e 37 anos. Do total, 13 (4,2%) foram considerados indivíduos cor-deficientes: 8 (6,6%) homens e 5 (2,6%) mulheres. Após a análise estatística, pudemos afirmar que, com 95% de probabilidade, a proporção real de homens cor-deficientes está no intervalo de 3,14% a 12,16%; e a proporção real de mulheres cor-deficientes está no intervalo de 0,96% a 5,68%. Rejeitamos a hipótese de que a população feminina deste estudo está de acordo com a encontrada na literatura. Por outro lado, a população masculina deste estudo parece estar de acordo com os achados da literatura.

Color vision in school children: evaluation of a new test

OBJECTIVE: To compare standard color vision test results (Ishihara test) with a new test developed by the authors ("crayon" test) for the detection of congenital dyschromatopsia. METHODS: Cross-sectional study of 712 children from three public schools and one private school in the city of Porto Alegre, state of Rio Grande do Sul. Children with learning disabilities, or systemic and ocular diseases were excluded from this random sample. Two color vision tests, Ishihara test (short version with 14 plates) and crayon test (developed by the authors) were sequentially applied. Each test was applied by different evaluators and analyzed by a third evaluator. RESULTS: The crayon test showed a specificity of 100% (99.3-100%) and sensitivity of 38.5% (15.1-67.7%) when compared to Ishihara test. The prevalence of congenital dyschromatopsia in this population sample was 2.6% for male children, and 0.9% for female children. CONCLUSIONS: The crayon test results showed greater specificity than Ishihara test in the studied group; however, sensitivity was not adequate for a screening test. It is necessary to improve the sensitivity so that congenital dyschromatopsia can be detected by the crayon test.

Congenital dyschromatopsia and school achievement.

In 1993-94, in Liguria (a northwestern Italian region) a study was carried out on dyschromatopsia, a congenital sex-linked form of colour blindness. 3124 junior high school boys aged 10-15 years were tested using Ishihara plates (1973 edition) and Farnsworth's D-15 test (1947 edition). 152 students were identified as colour blind (4.87%), a value slightly below the Italian average of 5.3%. The school achievement of these students was assessed by means of the school marks of two randomised subsamples composed of 82 dyschromates and 82 orthochromates, paired homogeneously by age and class. Statistical analysis indicated significantly lower general school achievement for the 82 dyschromate subjects (except for art). The learning difficulties of dyschromate persons for whom colour is a basic didactic tool are discussed. Introduction of dyschromatopsia tests at preschool would be desirable.

Blue-yellow deficiency in workers exposed to low concentrations of organic solvents.

To evaluate the effects of low concentrations of organic solvents on color vision. Color vision was examined in 24 workers exposed to mixtures of solvents and in 24 control subjects. Exposure to mixtures was below the threshold-limit values. Color vision ability was assessed using the Ishihara plates (to screen for congenital dyschromatopsia), the Farnsworth panel D-15 test, the Lanthony desaturated panel D-15 test, and the Standard Pseudoisochromatic Plates part 2 (SPP2 test). The comparatively less sensitive Farnsworth panel D-15 test failed to show any difference between the groups, but the Lanthony panel D-15 desaturated test as well as the SPP2 test showed a significant impairment in the exposed group. Errors were of the blue-yellow type. This study gives further evidence that even mixtures of organic solvents at concentrations below the threshold-limit values may impair color vision.

Empirical detection of congenital dyschromatopsia by electroretinography.

The electroretinographic rapid off-response, composed mainly of the late receptor potential of cones, is found to be abnormal in all protans and deutans so far tested. The rapid off-response can thus be used as an objective measure in the diagnosis of congenital red-green colour defect.