Use of an application on the measles vaccine for Warao indigenous refugees in Brazil.

Objective: To evaluate the need to develop an application with information about the measles vaccine for Warao indigenous people.

Methods: This was a quantitative study conducted at the Espaço de Acolhimento Tapanã refugee shelter in the city of Belém, Pará, Brazil. The study sample was selected for convenience.

Chromatic discrimination in fixed saturation levels from tufted capuchin monkeys with different color vision genotypes.

Recent research has proposed new approaches to investigate color vision in Old World Monkeys by measuring suprathreshold chromatic discrimination. In this study, we aimed to extend this approach to New World Monkeys with different color vision genotypes by examining their performance in chromatic discrimination tasks along different fixed chromatic saturation axes. Four tufted capuchin monkeys were included in the study, and their color vision genotypes were one classical protanope, one classical deuteranope, one non-classical protanope, and a normal trichromat.

High prevalence of sexual infection by human papillomavirus and Chlamydia trachomatis in sexually-active women from a large city in the Amazon region of Brazil.

Background: The Human Papillomavirus (HPV) and Chlamydia trachomatis are the most prevalent Sexually Transmitted Infections (STIs) worldwide, and are associated cervical cancer and pelvic inflammatory disease, respectively. However, 80% of women testing positive are asymptomatic. In the Amazon region, young women, in particular, are widely exposed to the infections and their consequences.

Comparison of Visual Functions of Two Amazonian Populations: Possible Consequences of Different Mercury Exposure.

The present study investigated the visual perimetry and color vision of two Amazonian populations differently exposed to mercury. Ten riverines environmentally exposed to mercury by fish eating and 34 gold-miners occupationally exposed to mercury vapor. The visual perimetry was estimated using the Förster perimeter and the color vision was evaluated using a computerized version of Farnsworth-Munsell test.

A proposed correction in the weighted method to score the Ishihara test.

Objective: Ishihara test is a color vision test, whose results consider that all plates of the test have the same weighting. Rodriguez-Carmona et al. (Aviat Space Environ Med 83:19-29, 2012) proposed an equation to quantify the Ishihara test results (severity index), which took an account the rate of hits from the different plates of the test considering the performance of trichromat or colorblind population.

Psychophysical Evaluation of Visual Functions of Ex-Alcoholic Subjects After Prolonged Abstinence.

Chronic alcohol abuse can lead to a brain damages, and the health status of alcoholics even after a long-term alcohol abstinence is a public health concern. The present study investigated the color vision and spatial luminance contrast sensitivity of a group of 17 ex-alcoholics (46.3 ± 6.

Incomplete myelopathy and human T cell lymphotropic virus type-1 (HTLV-1).

This was a cross-sectional prospective study. We performed a multivariate statistical analysis of the neurological signs and symptoms of patients infected with human T cell lymphotropic virus type 1 (HTLV-1) in an attempt to separate them into distinct groups and identify clinical-neurological manifestations that could differentiate the various profiles. The study was performed in the city of Belém (state of Pará), located in the Amazon region of Brazil, from 2014 to 2016.

Color vision impairment with low-level methylmercury exposure of an Amazonian population - Brazil.

Land exploitation that follows deforestation and mining can result in soil erosion and the release of mercury to the waters of rivers in the Amazon Basin. Inorganic mercury is methylated by bacteria that are present in the environment and it serves as a source of human contamination through fish consumption in the form of methylmercury. Long-term exposure to low-level methylmercury in the riverside populations can lead to nervous system alterations, some of which are visual impairments such as loss of luminance contrast sensitivity, restricted visual fields and color vision defects.

Evidence of Asymptomatic Visual Losses after Surgical Repair of Cerebral Aneurysm.

Deficits in visual acuity, visual field, and oculomotor function are commonly detected after repair of cerebral aneurysms. However, when these deficits are absent, it does not mean that other potential visual deficits also are absent. Here, we report three cases that after complete recover from surgical repair of cerebral aneurysms presented minimal visual acuities of about 20/20 and no visual disturbances.

Psychophysical Evaluation of Congenital Colour Vision Deficiency: Discrimination between Protans and Deutans Using Mollon-Reffin's Ellipses and the Farnsworth-Munsell 100-Hue Test.

We have used the Farnsworth-Munsell 100-hue (FM 100) test and Mollon-Reffin (MR) test to evaluate the colour vision of 93 subjects, 30.4 ± 9.7 years old, who had red-green congenital colour vision deficiencies.

Colour Vision Impairment in Young Alcohol Consumers.

Alcohol consumption among young adults is widely accepted in modern society and may be the starting point for abusive use of alcohol at later stages of life. Chronic alcohol exposure can lead to visual function impairment. In the present study, we investigated the spatial luminance contrast sensitivity, colour arrangement ability, and colour discrimination thresholds on young adults that weekly consume alcoholic beverages without clinical concerns.

Influence of retinopathy on the achromatic and chromatic vision of patients with type 2 diabetes.

Background: Luminance contrast sensitivity and colour vision are considered to have great predictive value in the evaluation of type 2 diabetic retinopathy. However, these two visual characteristics have seldom been investigated in the same group of patients. In the present study we measured contrast sensitivity and colour vision in a group of patients with type 2 diabetes and correlated the results with estimates of common metabolic markers for the disease.

Evidence for two types of lateral interactions in visual perception of temporal signals.

The aim of this work was to investigate the mechanisms of lateral interactions involved in flicker perception. Furthermore, the spatial properties of the monoptic and dichoptic components of these mechanisms were studied. We quantified the perceived flicker strength (PFS) in the center of a test stimulus, which was simultaneously modulated with a surround stimulus of variable size.

Joint entropy for space and spatial frequency domains estimated from psychometric functions of achromatic discrimination.

We used psychometric functions to estimate the joint entropy for space discrimination and spatial frequency discrimination. Space discrimination was taken as discrimination of spatial extent. Seven subjects were tested.

Psychophysical evaluation of achromatic and chromatic vision of workers chronically exposed to organic solvents.

The purpose of this paper was to evaluate achromatic and chromatic vision of workers chronically exposed to organic solvents through psychophysical methods. Thirty-one gas station workers (31.5 ± 8.

Spatial distributions of on- and off-responses determined with the multifocal ERG.

We studied the contribution of retinal on and off-mechanisms in the multifocal electroretinogram (mfERG) by measuring responses to saw tooth stimuli. Six healthy subjects participated in this study. Rapid-on and rapid-off sawtooth stimuli with a period of 427 ms were presented in a multifocal pattern composed of 19 hexagons.

Flicker ERGs representing chromaticity and luminance signals.

Purpose: To test the hypothesis that electroretinograms (ERGs) reflect luminance activity when measured at high temporal frequencies and chromatic activity when measured near 12 Hz.

Methods: The authors measured the responses to stimuli in which the output of red and green light-emitting diodes was modulated in counterphase at different ratios, varying the luminance content in the stimulus while keeping the red-green chromatic contrast and its phase constant.

Results: The high temporal frequency electroretinography was determined mainly by the luminance contrast.

Rod bipolar cells in the retina of the capuchin monkey (Cebus apella): characterization and distribution.

Rod bipolar cells in Cebus apella monkey retina were identified by an antibody against the alpha isoform of protein kinase C (PKCalpha), which has been shown to selectively identify rod bipolars in two other primates and various mammals. Vertical sections were used to confirm the identity of these cells by their characteristic morphology of dendrites and axons. Their topographic distribution was assessed in horizontal sections; counts taken along the dorsal, ventral, nasal, and temporal quadrants.

Color discrimination ellipses of trichromats measured with transient and steady state visual evoked potentials.

The purpose of this work is to investigate the use of different forms of visual evoked potentials (VEPs) to measure color discrimination thresholds and to plot color discrimination ellipses (MacAdam, 1942). Five normal trichromats (24.5 +/- 2.

Normal and dichromatic color discrimination measured with transient visual evoked potential.

It would be informative to have an electrophysiological method to study, in an objective way, the effects of mercury exposure and other neurotoxics on human color vision performance. The purpose of the present work was to study human color discrimination by measuring chromatic difference thresholds with visual evoked potential (VEP). Six young normal trichromats (24 +/- 1 years old) and one deutan (26 years old) were tested.

Visual impairment on dentists related to occupational mercury exposure.

A detailed assessment of visual function was obtained in subjects with low-level occupational mercury exposure by measuring hue saturation thresholds and contrast sensitivity functions for luminance and chromatic modulation. General practice dentists (n=15) were compared to age-matched healthy controls (n=13). Color discrimination estimated by the area of Mac Adam ellipses was impaired, showing diffuse discrimination loss.