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RESUMO Investigou-se a relação entre percepção visual e tremor essencial (TE). Realizou-se uma revisão dos estudos publicados sobre o tema nas bases de dados PubMed, BIREME, CINAHL, Web of Science, PsycINFO, SciELO, SCOPUS e ELSEVIER desde a origem até 05 de janeiro de 2017. A triagem, extração de dados e avaliação foram realizadas por dois revisores. Para avaliar a qualidade dos estudos utilizou-se as diretrizes do National Institutes of Health (NIH). De 132 estudos potencialmente elegíveis, 12 foram selecionados de acordo com os critérios de elegibilidade. Os resultados indicaram que pessoas com TE apresentam baixa sensibilidade visual quando comparados com indivíduos saudáveis, apesar de não apresentarem prejuízos na visão de cores. Apesar da heterogeneidade dos dados, observamos que existem prejuízos visuais em pessoas com TE e estes podem ser uma das principais características clínicas não-motoras.

ABSTRACT It was investigated whether essential tremor (ET) patients would exhibit visual impairments. Studies published in the following databases were reviewed: PubMed, BIREME, CINAHL, Web of Science, PsycINFO, SciELO, SCOPUS, and ELSEVIER, from inception to January 05th, 2017. Two independent reviewers performed screening, data extraction, and assessment of the data. The NIH assessment tools used to assess study quality. Out of 132 references, 12 were selected according to the eligibility criteria. Results indicated that ET patients have lower visual sensitivity when compared to control groups. There was no significant evidence for color vision impairment. Despite the findings for heterogeneity, visual impairments in ET patients were observed, and these may be one of the main non-motor clinical characteristics.

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This study, an extension of Fernandes et al. (2017), provided consistent contrast sensitivity function (CSF) measurements in a large sample. CSF was assessed for luminance stimuli in different 48 chronic smokers and 50 healthy nonsmokers. Stimuli for the CSF were Gabor patches with spatial frequencies of .2, 2.5, 5.0, 10.0, and 20.0 cycles per degree (cpd). The use of Gabor patches minimizes uncertainty in spatial position and detection of frequencies. The Gabor patches consisted of vertical gratings that were multiplied by a two-dimensional spatial Gaussian envelope. All of the groups were matched for gender and level of education. All of the participants were free from any neurological disorder, cardiovascular disease, and identifiable ocular disease, and they had normal or corrected-to-normal visual acuity. No abnormalities were detected on the fundoscopic examination or optical coherence tomographic examination. The smoker group had a lower CSF compared with healthy nonsmokers at all spatial frequencies. These results indicate that cigarette smoking or chronic exposure to its constituent compounds affects early-stage visual discrimination, suggesting the existence of deficits in early visual spatial processing in smokers.

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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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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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