Cigarette smoke is a complex chemical mixture, involving health-damaging components such as carbon monoxide, ammonia, pyridine, toluene and nicotine. While cognitive functions have been well documented in heavy smokers, spatial vision has been less characterized. In the article, we investigated smoking effects through contrast sensitivity function (CSF), a rigorous procedure that measures the spatial vision. Data were recorded from 48 participants, a group of non-smokers (n = 16), a group of chronic and heavy cigarette smokers (n = 16) and deprived smokers (n = 16); age range 20–45 years. Sinewave gratings with spatial frequencies ranging from 0.25 to 20 cycles per degree were used. All subjects were free from any neurological disorder, identifiable ocular disease and had normal acuity. No abnormalities were detected in the fundoscopic examination and in the optical coherence tomography exam. Contrary to expectations, performance on CSF differed between groups. Both smokers and deprived smokers presented a loss of contrast sensitivity compared to non-smokers. Post-hoc analyses suggest that deprived smokers were less sensitive at all spatial frequencies. These results suggest that not only chronic exposure to cigarette compounds but also withdrawal from nicotine affected spatial vision. This highlights the importance of understanding diffuse effects of smoking compounds on visual spatial processing.

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Purpose The goals of the study were to further assess contrast sensitivity to (1) investigate the existence of monocular vs. binocular differences; (2) observe possible differences between sample sizes; (3) investigate the effects of test-retest repeatability. Methods Contrast sensitivity measurements were obtained by presenting eight horizontal sine-wave gratings (ranging from 0.2 to 20 cycles per degree). A three-up-one-down method was used to obtain thresholds with a criterion of 79.4% correct responses for each spatial frequency. The mean of 12 reversals was used for obtaining thresholds, and the two-alternative forced-choice method was used. Data were recorded in 55 naive observers from 20 to 45 years. All participants were free from identifiable ocular disease and had normal visual acuity. Results We observed the absence of differences on CSF for both monocular and binocular observers, as well as the absence of differences between large sample sizes. The latter investigation revealed a high degree of repeatability across time (baseline to 6 months later) with the higher test-retest for low and high spatial frequencies. Conclusions Our results indicated that spatial contrast sensitivity measurements were little influenced by variables, such as binocular summation, eye dominance, sample size and time using the Metropsis test. The results obtained here have significance for basic and clinical vision science.

Alcohol is one of the most consumed psychoactive substances in the world, and the negative impact related to alcohol use has become a worldwide public health issue. Alcohol is able to affect diffusely several areas of the Central Nervous System, which could impair visual functions, including eye movements, and cognitive processes. The objective of the present study was to investigate the effects of moderate alcohol intake in eyes movements, as an indicator of cognitive processing underlying the visual search in a the Maze task. We investigated the concentration of 0.08% blood alcohol concentration (BAC), using an intra-subject, double-blind, and placebo-controlled experimental design with a sample size of 20 young adults (11 men and nine women). All volunteers participated in both conditions, i.e., alcohol (0.08%) and placebo (0.00%), in a counterbalanced order. We use the Tobii TX300 eye tracker to evaluate eye movements during completion of Visual Maze Test. The results showed significant differences in the following eye movement patterns: the first fixation latency, number and duration of fixations (mean and total), the number and duration of saccades (mean and total), and the total execution time in the test. In addition, we investigate the areas of interest (AOI), decision points in which the participant must decide which course to follow. We verified that the participants in the alcohol condition had a significantly greater number of fixations in both AOI, in comparison to the placebo condition. Overall, our findings confirm that moderate doses of alcohol can change the eye movements of young adults. These alterations may evidence the influence of alcohol in cognitive processes, such as flexibility, attention, and planning, which are required during resolution of Maze Task.

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Background: Cigarette smoke is probably the most significant source of exposure to toxic chemicals for humans, involving health-damaging components, such as nicotine, hydrogen cyanide and formaldehyde. The aim of the present study was to assess the influence of chronic heavy smoking on color discrimination (CD). Methods: All subjects were free of any neuropsychiatric disorder, identifiable ocular disease and had normal acuity. No abnormalities were detected in the fundoscopic examination and in the optical coherence tomography exam. We assessed color vision for healthy heavy smokers ( n = 15; age range, 20-45 years), deprived smokers ( n = 15, age range 20-45 years) and healthy non-smokers ( n = 15; age range, 20-45 years), using the psychophysical forced-choice method. All groups were matched for gender and education level. In this test, the volunteers had to choose the pseudoisochromatic stimulus containing a test frequency at four directions (e.g., up, down, right and left) in the subtest of Cambridge Colour Test (CCT): Trivector. Results: Performance on CCT differed between groups, and the observed pattern was that smokers had lower discrimination compared to non-smokers. In addition, deprived smokers presented lower discrimination to smokers and non-smokers. Contrary to expectation, the largest differences were observed for medium and long wavelengths. Conclusions: These results suggests that cigarette smoking, chronic exposure to its compounds, and withdrawal from nicotine affect color discrimination. This highlights the importance of understanding the diverse effects of nicotine on attentional bias.

Objective: Chronic tobacco consumption, classified as tobacco use disorder (TUD), has been associated with a variety of health problems. Investigations of face processing in TUD are hampered by lack of evidence. Here, we evaluated facial detection in TUD and assessed test-retest reliability for a facial detection task. Methods: Participants were instructed to detect the orientation (either left or right) of a face when it was presented with a face/non-face pair on the monitor screen, using Bayesian entropy estimation. Bland-Altman analysis and intraclass correlation coefficients were used to test the reliability of the task. The general linear model and Bayesian statistics were then used to evaluate differences between TUD (n=48) and healthy controls (n=34). Results: The reliability of the task was high for the 96 stimuli presentations. Slower reaction times (p o 0.001) and lower discrimination index (p o 0.001) were observed in the TUD group than for healthy controls. Mediation analysis indicated direct effects of smoking duration on reaction time (p o 0.001) and discrimination index (p o 0.001). Conclusions: Overall, we observed high reliability of this task and reduction of facial detection in tobacco use disorder. We conclude our findings are significant for public health initiatives and call for follow-up studies.