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Achromatopsia (ACHM) is a congenital cone photoreceptor disorder characterized by reduced visual acuity, nystagmus, photophobia, and very poor or absent color vision. Pathogenic variants in six genes encoding proteins composing the cone phototransduction cascade (CNGA3, CNGB3, PDE6C, PDE6H, GNAT2) and of the unfolded protein response (ATF6) have been related to ACHM cases, while CNGA3 and CNGB3 alone are responsible for most cases. Herein, we provide a clinical and molecular overview of 42 Brazilian patients from 38 families affected with ACHM related to biallelic pathogenic variants in the CNGA3 and CNGB3 genes. Patients' genotype and phenotype were retrospectively evaluated. The majority of CNGA3 variants were missense, and the most prevalent CNGB3 variant was c.1148delC (p.Thr383Ilefs*13), resulting in a frameshift and premature stop codon, which is compatible with previous publications in the literature. A novel variant c.1893T>A (p.Tyr631*) in the CNGB3 gene is reported for the first time in this study. A great variability in morphologic findings was observed in our patients, although no consistent correlation with age and disease stage in OCT foveal morphology was found. The better understanding of the genetic variants landscape in the Brazilian population will help in the diagnosis of this disease.

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Purpose: To evaluate color vision changes and retinal processing of chromatic and luminance pathways in subjects with Alzheimer disease (AD) and mild cognitive impairment (MCI) compared with a matched control group and whether such changes are associated with impaired brain glucose metabolism and ß-amyloid deposition in the brain. Methods: We evaluated 13 patients with AD (72.4 ± 7.7 years), 23 patients with MCI (72.5 ± 5.5 years), and 18 controls of comparable age (P = 0.44) using Cambridge color test and the heterochromatic flicker ERG (HF-ERG). The Cambridge color test was performed using the trivector protocol to estimate the protan, deutan and tritan color confusion axes. HF-ERG responses were measured at a frequency of 12 Hz, which ERGs reflect chromatic activity, and at 36 Hz, reflecting luminance pathway. A study subsample was performed using neuropsychological assessments and positron emission tomography. Results: Patients with AD presented higher mean values indicating poorer color discrimination for protan (P = 0.04) and deutan (P = 0.001) axes compared with the controls. Along the tritan axis, both patients with AD and patients with MCI showed decreased color vision (P = 0.001 and P = 0.001) compared with controls. The analyses from the HF-ERG protocol revealed no differences between the groups (P = 0.31 and P = 0.41). Diffuse color vision loss was found in individuals with signs of neurodegeneration (protan P = 0.002, deutan P = 0.003 and tritan P = 0.01), but not in individuals with signs of ß-amyloid deposition only (protan P = 0.39, deutan P = 0.48, tritan P = 0.63), regardless of their clinical classification. Conclusions: Here, patients with AD and patients with MCI present acquired color vision deficiency that may be linked with impaired brain metabolism.

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Color vision tests use estimative of threshold color discrimination or number of correct responses to evaluate performance in chromatic discrimination tasks. Both approaches have advantages and disadvantages. In the present investigation, we compared the number of errors during color discrimination task in normal trichromats and participants with color vision deficiency (CVD) using pseudoisochromatic stimuli at fixed saturation levels. We recruited 28 normal trichromats and eight participants with CVD. Cambridge Color Test was used to categorize their color vision phenotype, and those with a phenotype suggestive of color vision deficiency had their L- and M-opsin genes genotyped. Pseudoisochromatic stimuli were shown with target chromaticity in 20 vectors radiating from the background chromaticity and saturation of 0.06, 0.04, 0.03, 0.02, 0.01, and 0.005 u'v' units. Each stimulus condition appeared in four trials. The number of errors for each stimulus condition was considered an indicator of the participant's performance. At high chromatic saturation, there were fewer errors from both phenotypes. The errors of the normal trichromats had no systematic variation for high saturated stimuli, but below 0.02 u'v' units, there was a discrete prevalence of tritan errors. For participants with CVD, the errors happened mainly in red-green chromatic vectors. A three-way ANOVA showed that all factors (color vision phenotype, stimulus saturation, and chromatic vector) had statistically significant effects on the number of errors and that stimulus saturation was the most important main effect. ROC analysis indicated that the performance of the fixed saturation levels to identify CVD was better between 0.02 and 0.06 u'v' units reaching 100%, while saturation of 0.01 and 0.005 u'v' units decreased the accuracy of the screening of the test. We concluded that the color discrimination task using high saturated stimuli separated normal trichromats and participants with red-green color vision deficiencies with high performance, which can be considered a promising method for new color vision tests based in frequency of errors.

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ABSTRACT Objective: The goal of the study is to analyze the color vision acuity pattern in undergraduates of health courses and to discuss the impact of these diseases in this population. Color deficiencies interfere significantly in the daily routine of professionals in the health area who need to discern different color hues in several situations of their everyday practice. Methods: Sixty-four volunteers, undergraduates of health courses of the Federal University of Alfenas (UNIFAL-MG), participated in the study. One man was excluded because he did not fit the inclusion criteria. Two groups were analyzed according to sex with the Farnsworth Munsell 100-Hue test. Results: There were no significant differences between the eyes and between the groups analyzed. The color vision acuity pattern is between 35 and 40, according to the Total Error Score. The gender issue does not influence the general pattern of the color vision acuity of the health courses undergraduates when those with color vision disorders are removed. Conclusion: Screenings and guidance should be given to undergraduates of health courses so that, aware of their condition of presenting some type of color disorder, they shall make the appropriate decision on which career to follow so that such limitation does not interfere with the quality of their daily life.

RESUMO Objetivo: O objetivo do estudo é analisar a acuidade visual média para cores de estudantes da área de saúde e discutir o impacto das doenças que a afetam nessa população. Deficiências cromáticas interferem de forma significativa no dia a dia de profissionais da área da saúde que necessitam de discernir diferentes matizes em diversas situações de sua prática profissional. Métodos: Participaram da pesquisa 64 voluntários, estudantes de cursos da área de saúde da Universidade Federal de Alfenas, sendo que 1 homem foi excluído por não se adequar aos critérios de inclusão. Dois grupos foram analisados, de acordo com o sexo, com o teste de Farnsworth Munsell 100-Hue. Resultados: Não houve diferenças significativas entre os olhos e entre os grupos analisados. O padrão de visão de cores encontra-se entre 35 e 40, de acordo com a Pontuação do Erro Total. A questão de gênero não influencia no padrão geral da qualidade de visão de cores de estudantes da área de saúde, quando retirados aqueles que apresentam distúrbios da visão cromática. Conclusão: Devem ser realizadas triagens e orientação para estudantes de cursos da área de saúde para que, cientes da sua condição de apresentar algum tipo de distúrbio cromático, possam tomar a decisão adequada sobre qual carreira seguir para que tal limitação não interfira na qualidade de sua vida diária.

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PURPOSE: Visual evoked cortical potentials (VECPs) are useful for investigating the mechanisms and dysfunctions of color vision. Chromatic sinusoidal gratings are generally used to elicit VECPs, but they require long psychophysical measurements to match the perceptual luminance between their stripes. An alternative method is to use pseudoisochromatic stimuli, which makes use of luminance noise to mask luminance clues and force the target perception to be dependent on chromatic contrast. In this study, we compared VECPs generated by sinusoidal gratings and pseudoisochromatic gratings. Contrary to chromatic sinusoidal gratings, pseudoisochromatic stimuli do not require the use of previous methods to find the equiluminance of the stimulus. METHODS: Normal trichromats were recruited to be tested with red-green chromatic sinusoidal gratings and pseudoisochromatic gratings presented by pattern onset-offset and pattern reversal modes in five spatial frequencies. In addition, we also tested four different chromatic contrast pairs in pattern onset-offset mode presentation in five trichromats and one colorblind subject (deuteranope). RESULTS: Pattern onset-offset VECPs elicited by sinusoidal gratings had a larger amplitude than those obtained with pseudoisochromatic stimuli, whereas pattern reversal VECPs elicited by pseudoisochromatic gratings had similar amplitudes compared to those elicited by sinusoidal gratings. We found no difference between the VECP amplitudes elicited by sinusoidal and pseudoisochromatic gratings containing different chromatic contrast. Color-blind subjects displayed absent or small responses to the stimuli. CONCLUSION: Pseudoisochromatic stimulus can be an alternative stimulus to generate VECPs dominated by the chromatic mechanism.

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Diabetes causes a panretinal neurodegeneration herein termed diabetic retinal neuropathy, which manifests in the retina early and progresses throughout the disease. Clinical manifestations include changes in the ERG, perimetry, dark adaptation, contrast sensitivity and colour vision which correlate with laboratory findings of thinning of the retinal neuronal layers, increased apoptosis in neurons and activation of glial cells. Possible mechanisms include oxidative stress, neuronal AGE accumulation, altered balance of neurotrophic factors and loss of mitohormesis. Retinal neural damage precedes and is a biologically plausible cause of retinal vasculopathy later in diabetes, and this review suggests that strategies to target it directly could prevent diabetes induced blindness. The efficacy of fenofibrate in reducing retinopathy progression provides a possible proof of concept for this approach. Strategies which may target diabetic retinal neuropathy include reducing retinal metabolic demand, improving mitochondrial function with AMPK and Sirt1 activators or providing neurotrophic support with neurotrophic supplementation.

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O termo "discromatopsia congênita" ("daltonismo") designa os defeitos de visão cromática, cuja taxa de prevalência entre homens é de 6% a 10%. Este estudo investigou as percepções de discromatópsicos quanto ao diagnóstico, suas dificuldades e mecanismos de enfrentamento do problema. Foi realizada pesquisa com metodologia clínica-qualitativa, na qual participaram 13 homens universitários, compondo uma amostra intencional, fechada por saturação teórica. Os dados foram coletados por meio de entrevistas individuais semiestruturadas. Os relatos foram gravados, transcritos e compuseram um corpus investigado pela técnica de análise de conteúdo categorial temática. Os participantes relataram dificuldades objetivas e subjetivas com materiais didáticos, práticas de ensino, interações com colegas e professores, já a partir do início da socialização secundária. Posteriormente, foram referidas, sobretudo, dificuldades relacionadas à decodificação de sinais de trânsito. Os participantes desenvolveram algumas habilidades de enfrentamento dessas dificuldades, mas aguardam ações a serem desencadeadas pelos poderes públicos, dirigidas ao atendimento das suas necessidades sociais, educacionais e trabalhistas...

The term congenital dyschromatopsia (colorblindness) refers to color vision genetic deficiency, whose prevalence rate is 6 to 10% among men. This study investigated the perceptions of subjects with congenital dyschromatopsia regarding diagnosis, their difficulties and coping mechanisms of the condition. This research was carried out using a clinical-qualitative methodology, in which 13 male university students took part, consisting of a purposeful sample concluded by theoretical saturation. Data were collected by conducting semi-structured individual interviews. Reports were recorded, transcribed and a corpus was made investigated by the technique of thematic categorical content. Participants reported objective and subjective difficulties with didactic material, teaching practice, interactions with colleagues and teachers, already from the beginning of their secondary socialization. Subsequently, difficulties in decoding traffic lights were mainly reported. Participants developed some coping skills to face these challenges, but await actions to be initiated by the Brazilian government to meet their social, education and labor needs...

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The authors describe two cases of hereditary dyschromatopsia and discuss the efficiency of the color vision tests. The patients were disapproved in different federal public examinations because Ishihara's test diagnosed hereditary dyschromatopsia. Ophthalmological evaluation was normal. No symptoms related to dyschromatopsia were presented. Panels D15 and Roth D 28 were normal. Desaturated D 15 showed deuteranomaly in case one. In the second case the comparative color vision tests showed nonspecific disorder. The diagnosis of dyschromatopsia is complex. The authors recommend comparative color vision tests to complement the Ishihara test for a better understanding of the color deficiency.

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As autoras relatam dois casos de discromatopsia hereditária e discutem a eficiência dos testes cromáticos no diagnóstico de uma discromatopsia. Os pacientes foram reprovados em diferentes concursos públicos federais por apresentarem diagnóstico de discromatopsia hereditária pelo teste de Ishihara. Submeteram-se a exame oftalmológico, com resultados dentro da normalidade. Procuraram novo parecer para melhor caracterização da sua discromatopsia. Não havia sintomas relacionados à deficiência. Os testes Panel D15 simples, D28 de Roth mostraram-se normais e o D15 dessaturado confirmou deutanomalia no caso 1. No segundo caso os testes de comparação mostraram alterações sem significado cromático. O diagnóstico de uma discromatopsia é muito complexo. As autoras destacam a importância de realização de testes de visão cromática complementares ao teste de Ishihara para diagnóstico de uma discromatopsia.

The authors describe two cases of hereditary dyschromatopsia and discuss the efficiency of the color vision tests. The patients were disapproved in different federal public examinations because Ishihara's test diagnosed hereditary dyschromatopsia. Ophthalmological evaluation was normal. No symptoms related to dyschromatopsia were presented. Panels D15 and Roth D 28 were normal. Desaturated D 15 showed deuteranomaly in case one. In the second case the comparative color vision tests showed nonspecific disorder. The diagnosis of dyschromatopsia is complex. The authors recommend comparative color vision tests to complement the Ishihara test for a better understanding of the color deficiency.

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PURPOSE: to evaluate the frequency of dyschromatopsias among the 10 to 45-year-old male Indian population of Lalima village, Terena ethnicity, in Miranda-MS, using the fourth edition of the pseudoisochromatic HRR test (Hardy, Rand and Rittler). METHODS: Lalima village in Miranda-MS was visited in January and February 2005. The visits only occurred after the approval of the project by the Committee of Ethics and Research of UFMS, by the National Committee of Ethics and Research, by the Indian National Foundation, and by the chief of Lalima village. The test was applied in 226 Indians who had been previously submitted to ophthalmologic examination for the detection of abnormalities that could doubt the applicability of the test. The test was performed under natural illumination, in sunny days, however with no direct sunlight. The test was applied and analyzed by the same experimenter in all the Indians. RESULTS: Two hundred and twenty-six men were examined (60.1%) of the total male population of 376 individuals between 10 and 45 years old who live in Lalima village. No cases of dyschromatopsia were found in this population examined with the HRR test. CONCLUSIONS: Once it is known that incidence of dyschromatopsias among the white male Caucasian population is about 6-8%, the results of the present study indicate a low prevalence of dyschromatopsias in this Indian population of Terena ethnicity, since no cases were detected in the examined sample. Other studies using different methods must be made to reinforce the present results. It would also be interesting to genetically examine this population and verify the genes that code for photopigments.

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