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Abstract The aim of this study was to analyze the contrast sensitivity of spatial luminance and the color discrimination thresholds of the protan, deutan, and tritan axes of people with leprosy. This study included 8 subjects with leprosy (M = 4, W = 4, M = 33.38 ± 8.7) and 8 healthy subjects (M = 4, W = 4, M = 30.89 ± 5.8). The contrast sensitivity was evaluated by the Metropsis software version 11.0 with vertical sinusoidal grids of frequencies of 0.2, 0.5, 1, 5, 10, and 16 cycles per degree of visual angle (cpd) and color vision by the desaturated Lanthony D15 tests and the trivector and ellipse protocols of the Cambridge Color Test. The results showed significant differences between the groups in the processing of spatial frequencies of 0.2 (U = 14; p = .018); 5.0 (U = 45.0; p = .001); 10.0 (U = 45.0; p = .001), and 16.0 (U = 45.0; p = .001) cpd. The difference in color recognition through D15d (U = 4.0; p = .002). Ellipse 2 (U = 10.0; p = .012) and ellipse 3 (U = 9.0; p = .009) were discriminated against. Overall, the results indicate that leprosy changes the visual processing of low, medium, and high spatial frequencies, as well as the sensitivity of the short wavelength (tritan line of confusion) and long (protan line of confusion) cones.

Este estudo teve como objetivo avaliar a curva de sensibilidade ao contraste para estímulos de grades senoidais verticais de frequências espaciais de 0,2; 0,6; 1; 3,1; 6,1; 8,8; 13,2 e 15,6 ciclos por grau de ângulo visual; em um ritmo de 24 horas de adultos saudáveis de diferentes cronotipos. Participaram desta pesquisa 18 voluntários do sexo masculino com idade de 19 a 31 anos (M=23,8; DP=3,29). Os participantes foram divididos em grupos de acordo com o cronotipo: Matutino (n=5), Intermediário (n=9) e Moderadamente vespertino (n=4). Utilizaram-se como instrumentos medidas neuropsicológicas e o software Metropsis para avaliar a Função de Sensibilidade ao Contraste (FSC). As medidas da FSC foram realizadas com o método psicofísico da escolha forçada entre duas alternativas espaciais. Os resultados apresentaram alterações nas dimensões relacionadas ao processamento cognitivo e na FSC de sujeitos Matutinos [F (14; 76303) = 38,92; p

Abstract The aim of this study was to measure visual contrast sensitivity (CS) of luminance using vertical sinusoidal gratings with spatial frequencies of 0.6, 2.5, 5.0 and 20.0 cycles per degree of visual angle in chronic alcoholics in abstinence period. The participants were 20 volunteers (26–59 years of age) divided into two groups: the study group (SG) consisted of 10 volunteers with a clinical history of chronic alcoholism abstinence and the control group (CG) consisted of 10 healthy volunteers. Each group had five female and five male participants. All participants had normal or corrected visual acuity and were free of identifiable diseases. The psychophysical method of forced choice between two temporal alternatives (2AFC) was used to measure visual CS of luminance of 41.2 cd/m2. The results showed significant differences between groups for all spatial frequencies tested (p< 0.001). These results suggest alterations in the visual perception related to chronic alcohol consumption even after years of abstinence.

This study aimed to evaluate the contrast sensitivity curve for the stimuli of vertical sinusoidal grids with spatial frequencies of .2; .6; 1; 3.1; 6.1; 8.8; 13.2 and 15.6 cycles per degree of visual angle, in a 24- hour rhythm of healthy adults of different chronotypes. This study had 18 participants aged 19 to 31 years (M=23.8; SD=3.29) divided into groups according to the chronotype: Morningness (n=5), Intermediate (n=9) and Moderate Eveningness (n=4). Neuropsychological measures and the Metropsis software were used to evaluate the Contrast Sensitivity Function (CSF). CSF measurements were performed by the psychophysical method of forced choice between two spatial alternatives. Results showed significant changes in the dimensions related to cognitive processing and CSF for morning subjects [F (14; 76303) = 38.92; p < .05], Intermediate subjects [F (14, 505) = 2.79; p< .05] and moderately evening subjects [F (14, 279) = 2.75; p< .05] in accordance with the measured time. The study concluded that contrast sensitivity is an important aspect to the study of circadian visual perception, suggesting that the sensorial mechanisms which process visual contrast are directly related to the time and pattern of people's chronotypes. [ABSTRACT FROM AUTHOR]