Influência da idade sobre a discriminação de luminância com mascaramento de ruído cromático

Abstract

Understanding the influence of the visual response to color contrasts and luminance is indispensable for a better understanding of visual processing under natural conditions. Current studies point out that with aging, humans present modifications in color perception and have decreased sensitivity especially after 40 years of age. Thus, we proposed in this research, to compare the influence of age on threshold perception of luminance masked by color noise in subjects distributed into two age groups, from 20 to 40 years old and over 50 years old, without comorbidities. This was an observational study of the cross-sectional analytic-descriptive type, conducted in the Neurology Laboratory of the Universidade Federal do Amapá - UNIFAP, where 42 volunteers participated, half for each age group, who were recruited through an invitation published in social networks. The participants were submitted to a previous interview to investigate the presence of neurological, metabolic and degenerative diseases that could compromise vision, then 03 psychophysical tests were performed, being 02 screening tests: the assessment of visual acuity (FrACT) and the Ishihara test and finally, the final test of this study for the evaluation of threshold luminance contrast discrimination with color masking. The risk that could arise from the research would be the extensive time spent performing the tests, which could lead to discomfort that could be relieved by taking breaks between tests and when requested by the participant. The benefits would be individual, due to the broad visual evaluation that the participant could enjoy; and collective, due to the contribution to the expansion of knowledge related to the interaction mechanisms between color and brightness in human vision, especially with advancing age. To assess data distribution, we applied the Shapiro-Wilk normality test. For analysis of variance, we used the one-way ANOVA test, followed by a Tukey's multiple comparisons test to compare parameters in each group; the unpaired Student's t-test with Welch's correction was used to compare parameters between groups. The results of the study confirm the hypothesis that advancing age affects the interaction between color and luminance, further corroborating the hypothesis that in the elderly the likely decrease in the perception of blue-yellow psychophysical mechanisms would induce decreased inhibition of color noise on threshold luminance perception.