Utility index and vision-related quality of life in patients awaiting specialist eye care.

OBJECTIVES: This study aimed to ascertain utility and vision-related quality of life in patients awaiting access to specialist eye care. A secondary aim was to evaluate the association of utility indices with demographic profile and waiting time. METHODS: Consecutive patients that had been waiting for ophthalmology care answered the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25). The questionnaire was administered when patients arrived at the clinics for their first visit. We derived a utility index (VFQ-UI) from the patients' responses, then calculated the correlation between this index and waiting time and compared utility across demographic subgroups stratified by age, sex, and care setting. RESULTS: 536 individuals participated in the study (mean age 52.9±16.6 years; 370 women, 69% women). The median utility index was 0.85 (interquartile range [IQR] 0.70-0.92; minimum 0.40, maximum 0.97). The mean VFQ-25 score was 70.88±14.59. Utility correlated weakly and nonsignificantly with waiting time (-0.05, P = 0.24). It did not vary across age groups (P = 0.85) or care settings (P = 0.77). Utility was significantly lower for women (0.84, IQR 0.70-0.92) than men (0.87, IQR 0.73-0.93, P = 0.03), but the magnitude of this difference was small (Cohen's d = 0.13). CONCLUSION: Patients awaiting access to ophthalmology care had a utility index of 0.85 on a scale of 0 to 1. This measurement was not previously reported in the literature. Utility measures can provide insight into patients' perspectives and support economic health analyses and inform health policies.

Influence of lighting on visual performance.

PURPOSE: This review emphasizes the effect of light on visual efficiency, the impact of different lighting focuses, types of lighting, and their influence on vision and productivity. Light sources and standards are intriguing subjects for ophthalmologists. Guidelines regarding the level of lighting influence on visual activities can enhance visual performance.Methods: This article was developed based on literature reviews, with a bibliographic survey conducted in databases such as PubMed, MEDLINE, Web of Science, Embase, LILACS, and SciELO. RESULTS: Provides recommendations for understanding information regarding the influence of lighting on visual performance. CONCLUSION: Proper workplace lighting is crucial for improving visual efficiency, safety, productivity, and worker health. Efficient workplace lighting should avoid light sources directed towards the worker's face, prevent harmful glare, be more intense in the work area, and uniform in the rest of the room. Ophthalmologists should be knowledgeable about and provide guidance on correct lighting to ensure patient comfort and satisfaction with visual correction.

The nature and distribution of putative non-functional alleles suggest only two independent events at the origins of Astyanax mexicanus cavefish populations.

BACKGROUND: Several studies suggested that cavefish populations of Astyanax mexicanus settled during the Late Pleistocene. This implies that the cavefish's most conspicuous phenotypic changes, blindness and depigmentation, and more cryptic characters important for cave life, evolved rapidly. RESULTS: Using the published genomes of 47 Astyanax cavefish from la Cueva de El Pachón, El Sótano de la Tinaja, La Cueva Chica and El Sótano de Molino, we searched for putative loss-of-function mutations in previously defined sets of genes, i.e., vision, circadian clock and pigmentation genes. Putative non-functional alleles for four vision genes were identified. Then, we searched genome-wide for putative non-functional alleles in these four cave populations. Among 512 genes with segregating putative non-functional alleles in cavefish that are absent in surface fish, we found an enrichment in visual perception genes. Among cavefish populations, different levels of shared putative non-functional alleles were found. Using a subset of 12 genes for which putative loss-of-function mutations were found, we extend the analysis of shared pseudogenes to 11 cave populations. Using a subset of six genes for which putative loss-of-function mutations were found in the El Sótano del Toro population, where extensive hybridization with surface fish occurs, we found a correlation between the level of eye regression and the amount of putative non-functional alleles. CONCLUSIONS: We confirm that very few putative non-functional alleles are present in a large set of vision genes, in accordance with the recent origin of Astyanax mexicanus cavefish. Furthermore, the genome-wide analysis indicates an enrichment of putative loss-of-function alleles in genes with vision-related GO-terms, suggesting that visual perception may be the function chiefly impacted by gene losses related to the shift from a surface to a cave environment. The geographic distribution of putative loss-of-function alleles newly suggests that cave populations from Sierra de Guatemala and Sierra de El Abra share a common origin, albeit followed by independent evolution for a long period. It also supports that populations from the Micos area have an independent origin. In El Sótano del Toro, the troglomorphic phenotype is maintained despite massive introgression of the surface genome.

Computational methodology to support functional vision assessment in premature infants: A viability study.

BACKGROUND: Premature newborns have a higher risk of abnormal visual development and visual impairment. OBJECTIVE: To develop a computational methodology to help assess functional vision in premature infants by tracking iris distances. METHODS: This experimental study was carried out with children up to two years old. A pattern of image capture with the visual stimulus was proposed to evaluate visual functions of vertical and horizontal visual tracking, visual field, vestibulo-ocular reflex, and fixation. The participants' visual responses were filmed to compose a dataset and develop a detection algorithm using the OpenCV library allied with FaceMesh for the detection and selection of the face, detection of specific facial points and tracking of the iris positions is done. A feasibility study was also conducted from the videos processed by the software. RESULTS: Forty-one children of different ages and diagnoses participated in the experimental study, forming a robust dataset. The software resulted in the tracking of iris positions during visual function evaluation stimuli. Furthermore, in the feasibility study, 8 children participated, divided into Pre-term and Term groups. There was no statistical difference in any visual variable analyzed in the comparison between groups. CONCLUSION: The computational methodology developed was able to track the distances traveled by the iris, and thus can be used to help assess visual function in children.

The Metabolism of 2-arachidonoylglycerol in Rod Outer Segments Is Modulated by Proteins Involved in the Phototransduction Process.

We previously reported that 2-arachidonoylglycerol (2-AG) synthesis by diacylglycerol lipase (DAGL) and lysophosphatidate phosphohydrolase (LPAP) and hydrolysis by monoacylglycerol lipase (MAGL) in rod outer segments (ROS) from bovine retina were differently modified by light applied to the retina. Based on these findings, the aim of the present research was to evaluate whether 2-AG metabolism could be modulated by proteins involved in the visual process. To this end, ROS kept in darkness (DROS) or obtained in darkness and then subjected to light (BROS) were treated with GTPγS and GDPßS, or with low and moderate ionic strength buffers for detaching soluble and peripheral proteins, or soluble proteins, respectively. Only DAGL activity was stimulated by the application of light to the ROS. GTPγS-stimulated DAGL activity in DROS reached similar values to that observed in BROS. The studies using different ionic strength show that (1) the highest decrease in DROS DAGL activity was observed when both phosphodiesterase (PDE) and transducin α (Tα) are totally membrane-associated; (2) the decrease in BROS DAGL activity does not depend on PDE association to membrane, and that (3) MAGL activity decreases, both in DROS and BROS, when PDE is not associated to the membrane. Our results indicate that the bioavailability of 2-AG under light conditions is favored by G protein-stimulated increase in DAGL activity and hindered principally by Tα/PDE association with the ROS membrane, which decreases DAGL activity.

A fase terminal do filho com câncer: percepções dos profissionais hospitalares / The terminal phase of children with cancer: perceptions of hospital professionals / La fase terminal del hijo con cáncer: percepciones de los profesionales del hospital

O confronto com o câncer de um filho e a percepção da sua morte como inevitável dão lugar a experiências parentais relevantes para a pesquisa científica. Este estudo teve como objetivo investigar, por meio da percepção dos profissionais hospitalares, o modo como os pais experienciam a fase terminal e fim de vida do filho com câncer para melhor compreender os processos psicoemocionais experienciados por esses pais diante da cronicidade da doença e da morte do filho. No sentido de alcançar esse objetivo, realizou-se um estudo qualitativo de tipo fenomenológico envolvendo 17 profissionais de dois hospitais portugueses de referência em oncologia pediátrica. Os dados foram recolhidos com recurso a um guia de entrevista semiestruturada. Na percepção dos profissionais hospitalares, os resultados evidenciam que esses pais experienciam múltiplas dificuldades e preocupações na fase terminal da doença do filho e no pós-morte, bem como um sofrimento extremo e desestruturação biopsicossocial e espiritual na família. O conhecimento aprofundado da fenomenologia desses processos é essencial para o desenho e a implementação de intervenções emocionais, cognitivas, comportamentais e sociais mais ajustadas às dificuldades e preocupações parentais vividas no fim de vida e pós-morte.(AU)

Coping with children's cancer and the perception of their inevitable death give rise to parental experiences that are important to study. This study aimed to investigate, based on hospital professionals' perspectives, how parents experience the terminal phase and end of life of their children suffering from cancer to better understand the psycho-emotional processes these parents experienced in face of the chronicity of the disease and their children's death. To achieve this objective, a qualitative phenomenological study was carried out involving 17 professionals of two Portuguese hospitals that are reference in pediatric oncology. Data were collected using a semi-structured interview guide. From the perspective of hospital professionals, results show that these parents experience multiple difficulties and concerns in the terminal phase of their children's disease and postmortem, as well as the extreme suffering and biopsychosocial and spiritual disruption of the family. A deeper understanding of the phenomenology of these processes is essential to design and implement better adjusted emotional, cognitive, behavioral, and social interventions aimed at the parental difficulties and concerns experienced at the end of life and after death.(AU)

El enfrentamiento del cáncer de un hijo y la percepción de su muerte como inevitable dan lugar a experiencias parentales importantes que deben ser estudiadas. Este estudio pretende identificar desde la percepción de los profesionales del hospital cómo los padres viven la fase terminal y el final de la vida de su hijo con cáncer con el fin de comprender mejor los procesos psicoemocionales que viven estos padres ante la cronicidad de la enfermedad y la muerte de su hijo. Para ello, se realizó un estudio cualitativo, con enfoque fenomenológico, en el que participaron 17 profesionales de dos hospitales portugueses de referencia en oncología pediátrica. Para recoger los datos se aplicó un guion de entrevista semiestructurada. En cuanto a la percepción de los profesionales del hospital, estos padres experimentaron múltiples dificultades y preocupaciones en la fase terminal de la enfermedad de su hijo y postmuerte, así como un sufrimiento extremo y una desestructuración biopsicosocial y espiritual en la familia. El conocimiento en profundidad de la fenomenología de estos procesos es esencial para elaborar e implementar intervenciones emocionales, cognitivas, conductuales y sociales más acordes a las dificultades y preocupaciones parentales que se experimentan al final de la vida y la postmuerte.(AU)

Crypsis by background matching and disruptive coloration as drivers of substrate occupation in sympatric Amazonian bark praying mantises.

Background matching and disruptive coloration are common camouflage strategies in nature, but few studies have accurately measured their protective value in living organisms. Amazon's Bark praying mantises exhibit colour patterns matching whitish and greenish-brown tree trunks. We tested the functional significance of background matching and disruptive coloration of different praying mantis morphospecies (white, grey and green) detected by DNA barcoding. Through image analysis, avian visual models and field experiments using humans as potential predators, we explored whether the background occupation of mantises provides camouflage against predation. Data were obtained for individuals against their occupied tree trunks (whitish or greenish-brown) and microhabitats (lichen or bryophyte patches), compared to non-occupied trunks. White and grey mantises showed lower colour contrasts against occupied trunks at the scale of tree trunk, with no differences in luminance contrasts. Conversely, green mantises showed lower colour and luminance contrasts against microhabitats and also exhibited high edge disruption against greenish-brown trunks. The camouflage of white and green mantis models against colour-matching trunks increased search time and reduced encounter distance of human predators. We highlight the importance of camouflage strategies at different spatial scales to enhance individual survival against predators. Specifically, we present a stunning study system to investigate the relationship of phylogenetically related species that use camouflage in sympatry.

Factores asociados a baja agudeza visual en una población escolar de la ciudad de Bucaramanga, Colombia / Factors Associated with Low Visual Acuity in a School Population in the City of Bucaramanga, Colombia / Fatores associados à baixa acuidade visual em uma população escolar da cidade de Bucaramanga, Colômbia

Introducción. La baja agudeza es un problema de salud pública en el mundo, que aumenta año tras año, relacionada con factores comportamentales poco saludables como el sedentarismo. La baja agudeza afecta especialmente a escolares, en quienes la visión representa uno de los sistemas más importantes para su desarrollo, tanto para el aprendizaje como para las relaciones sociales. El objetivo es establecer asociación entre baja agudeza visual y características sociodemográficas y comportamentales en una población escolar de la ciudad de Bucaramanga, Colombia. Metodología. Estudio observacional de corte transversal basado en datos recolectados de encuestas a estudiantes de una institución educativa de Bucaramanga entre los años 2006 y 2017, sobre las cuales se realizó un análisis bivariado entre características sociodemográficas y comportamentales con baja agudeza visual. Resultados. La prevalencia de baja agudeza visual fue de 33.57%, con mayor prevalencia de baja agudeza visual en mujeres y aquellos con mayor índice de masa corporal. La agudeza visual baja no tuvo asociación estadísticamente significativa con las otras variables estudiadas. Discusión. Las mujeres tienen una mayor prevalencia de baja agudeza visual. Parece existir una relación entre la actividad física y la agudeza visual. Conclusiones. Las diferencias encontradas según el sexo pueden deberse a patrones comportamentales diferentes entre hombres y mujeres, como la actividad física y el sedentarismo. Hacen falta estudios que evalúen la causalidad de la asociación entre los problemas de agudeza visual y los hábitos de vida poco saludables. Palabras clave: Agudeza Visual; Adolescente; Conducta Sedentaria; Visión Ocular; Baja Visión.

Introduction. Low visual acuity is a public health problem worldwide, which is increasing year by year, and it is associated with unhealthy behavioral factors such as sedentary lifestyle. Low visual acuity particularly affects schoolchildren, whom eyesight is one of the most important abilities for their development, both in terms of learning and social interactions. The objective of this study is to establish an association between low visual acuity, sociodemographic, and behavioral characteristics of a student population in Bucaramanga, Colombia. Methodology. This was a cross-sectional observational study based on data collected from surveys of students within an educational institution sited in Bucaramanga between 2006 and 2017. A bivariate analysis was conducted between sociodemographic and behavioral characteristics and low visual acuity. Results. The prevalence of low visual acuity was 33.57%, with a higher prevalence of low visual acuity in women and those with a higher body mass index. However, low visual acuity didn't have a statistically significant association with the other variables studied. Discussion. Women have a higher prevalence of low visual acuity. There appears to be an association between physical activity and visual acuity. Conclusions. The encountered differences according to sex may be due to different behavioral patterns between males and females, such as physical activity and sedentary lifestyle. Further studies are needed to assess the causality of the association. Keywords: Visual Acuity; Adolescent; Sedentary Behavior; Vision, Ocular; Vision, Low.

Introdução. A baixa acuidade é um problema de saúde pública no mundo, que aumenta a cada ano, relacionada a fatores comportamentais pouco saudáveis, como o sedentarismo. A baixa acuidade atinge especialmente as crianças em idade escolar, para as quais a visão representa um dos sistemas mais importantes para o seu desenvolvimento, tanto para a aprendizagem quanto para as relações sociais. O objetivo é estabelecer uma associação entre baixa acuidade visual e características sociodemográficas e comportamentais em uma população escolar na cidade de Bucaramanga, Colômbia. Metodologia. Estudo observacional transversal baseado em dados coletados em pesquisas com estudantes de uma instituição de ensino de Bucaramanga entre 2006 e 2017, nos quais foi realizada uma análise bivariada entre características sociodemográficas e comportamentais com baixa acuidade visual. Resultados. A prevalência de baixa acuidade visual foi de 33.57%, com maior prevalência de baixa acuidade visual em mulheres e naqueles com maior índice de massa corporal. A baixa acuidade visual não teve associação estatisticamente significativa com as demais variáveis estudadas. Discussão. As mulheres apresentam maior prevalência de baixa acuidade visual. Parece haver uma relação entre atividade física e acuidade visual. Conclusões. As diferenças encontradas segundo o sexo podem ser decorrentes de diferentes padrões comportamentais entre homens e mulheres, como atividade física e sedentarismo. Estudos são necessários para avaliar a causalidade da associação entre problemas de acuidade visual e hábitos de vida pouco saudáveis. Palavras-chave: Acuidade Visual; Adolescente; Comportamento Sedentário; Visão Ocular; Baixa Visão.

On the Functional Role of Gamma Synchronization in the Retinogeniculate System of the Cat.

Fast gamma oscillations, generated within the retina, and transmitted to the cortex via the lateral geniculate nucleus (LGN), are thought to carry information about stimulus size and continuity. This hypothesis relies mainly on studies conducted under anesthesia and the extent to which it holds under more naturalistic conditions remains unclear. Using multielectrode recordings of spiking activity in the retina and the LGN of both male and female cats, we show that visually driven gamma oscillations are absent for awake states and are highly dependent on halothane (or isoflurane). Under ketamine, responses were nonoscillatory, as in the awake condition. Response entrainment to the monitor refresh was commonly observed up to 120 Hz and was superseded by the gamma oscillatory responses induced by halothane. Given that retinal gamma oscillations are contingent on halothane anesthesia and absent in the awake cat, such oscillations should be considered artifactual, thus playing no functional role in vision.SIGNIFICANCE STATEMENT Gamma rhythms have been proposed to be a robust encoding mechanism critical for visual processing. In the retinogeniculate system of the cat, many studies have shown gamma oscillations associated with responses to static stimuli. Here, we extend these observations to dynamic stimuli. An unexpected finding was that retinal gamma responses strongly depend on halothane concentration levels and are absent in the awake cat. These results weaken the notion that gamma in the retina is relevant for vision. Notably, retinal gamma shares many of the properties of cortical gamma. In this respect, oscillations induced by halothane in the retina may serve as a valuable preparation, although artificial, for studying oscillatory dynamics.

An Overview towards Zebrafish Larvae as a Model for Ocular Diseases.

Despite the obvious morphological differences in the visual system, zebrafish share a similar architecture and components of the same embryonic origin as humans. The zebrafish retina has the same layered structure and cell types with similar metabolic and phototransduction support as humans, and is functional 72 h after fertilization, allowing tests of visual function to be performed. The zebrafish genomic database supports genetic mapping studies as well as gene editing, both of which are useful in the ophthalmological field. It is possible to model ocular disorders in zebrafish, as well as inherited retinal diseases or congenital or acquired malformations. Several approaches allow the evaluation of local pathological processes derived from systemic disorders, such as chemical exposure to produce retinal hypoxia or glucose exposure to produce hyperglycemia, mimicking retinopathy of prematurity or diabetic retinopathy, respectively. The pathogenesis of ocular infections, autoimmune diseases, or aging can also be assessed in zebrafish larvae, and the preserved cellular and molecular immune mechanisms can be assessed. Finally, the zebrafish model for the study of the pathologies of the visual system complements certain deficiencies in experimental models of mammals since the regeneration of the zebrafish retina is a valuable tool for the study of degenerative processes and the discovery of new drugs and therapies.

Retinorecipient areas in the common marmoset (Callithrix jacchus): An image-forming and non-image forming circuitry.

The mammalian retina captures a multitude of diverse features from the external environment and conveys them via the optic nerve to a myriad of retinorecipient nuclei. Understanding how retinal signals act in distinct brain functions is one of the most central and established goals of neuroscience. Using the common marmoset (Callithrix jacchus), a monkey from Northeastern Brazil, as an animal model for parsing how retinal innervation works in the brain, started decades ago due to their marmoset's small bodies, rapid reproduction rate, and brain features. In the course of that research, a large amount of new and sophisticated neuroanatomical techniques was developed and employed to explain retinal connectivity. As a consequence, image and non-image-forming regions, functions, and pathways, as well as retinal cell types were described. Image-forming circuits give rise directly to vision, while the non-image-forming territories support circadian physiological processes, although part of their functional significance is uncertain. Here, we reviewed the current state of knowledge concerning retinal circuitry in marmosets from neuroanatomical investigations. We have also highlighted the aspects of marmoset retinal circuitry that remain obscure, in addition, to identify what further research is needed to better understand the connections and functions of retinorecipient structures.

A monocular wide-field speed sensor inspired by the crabs' visual system for traffic analysis.

The development of visual sensors for traffic analysis can benefit from mimicking two fundamental aspects of the visual system of crabs: their panoramic vision and their visual processing strategy adapted to a flat world. First, the use of omnidirectional cameras in urban environments allows for analyzing the simultaneous movement of many objects of interest over broad areas. This would reduce the costs and complications associated with infrastructure: installation, synchronization, maintenance, and operation of traditional vision systems that use multiple cameras with a limited field of view. Second, in urban traffic analysis, the objects of interest (e.g. vehicles and pedestrians) move on the ground surface. This constraint allows the calculation of the 3D trajectory of the vehicles using a single camera without the need to use binocular vision techniques.The main contribution of this work is to show that the strategy used by crabs to visually analyze their habitat (monocular omnidirectional vision with the assumption of a flat world ) is useful for developing a simple and effective method to estimate the speed of vehicles on long trajectories in urban environments. It is shown that the proposed method estimates the speed with a root mean squared error of 2.7 km h-1.

Effects of the Interference of Sensory Systems on Postural Control in Congenitally Blind Subjects.

The postural system requires the sensory systems to maintain postural control (PC). Blind subjects use the somatosensory system to keep PC whereas sighted subjects use the visual system. So what happens to PC when challenging the sensory systems? We analyzed the center of pressure (COP) in ten blind and 10 sighted subjects under conditions: eyes open/closed (interference of visual system) and on firm/foam surfaces (interference of somatosensory system). We found that under the condition of eyes open on a firm surface, the blind subjects relied on the somatosensory system, whereas sighted subjects relied on the visual system. However, when eyes closed and on foam surface, similar behavior was found in both groups for all COP variables. In general blind subjects use their somatosensory system as the main sensory input to maintain PC.

Psychometric Properties of Scales for Assessing the Vision-related Quality of Life of People with Low Vision: A Systematic Review.

OBJECTIVE: To synthesize information on the psychometric properties of scales used to assess vision-related quality of life in people with low vision. METHODS: A systematic review was conducted. The Cochrane Library, Embase, PubMed, Bireme and Epistemonikos databases were consulted in July 2020. Eligibility assessment of abstracts and full texts was performed independently by two investigators.A standardized template was used for data extraction regarding study design, scale and version, clinical condition of participants, and psychometric properties measured, using database-specific controlled vocabulary terms for low vision and keywords for vision-related quality of life and validity. Data was synthesized considering two approaches for scales validations, Classical Test Theory and Rasch Analysis. RESULTS: A total of 53 articles were included in our analysis. In total, 40 studies evaluated the NEI VFQ scale, four evaluated the IVI scale, two evaluated the VA LV VFQ instrument and seven validated the LVQOL scale. This review found that the VRQoL NEI VFQ, IVI, LVQOL and VA LV VFQ-48 scales have adequate psychometric properties, with good internal consistency, when assessed using the CTT approach. The NEI VFQ scale also showed adequate test-retest reliability and adequate construct and content validity. The NEI VFQ and LVQOL scales showed inadequate items and multidimensionality when Rasch analysis was used. The IVI scale showed potential for assessing change in HRQoL after providing interventions to patients with low vision. CONCLUSIONS: Many questionnaires exist to measure vision-related quality of life in people with low vision, but the psychometric properties of the questionnaires are variable.

The nuclear factor E2-related factor 2 and age-related macular degeneration.

After the discovery of anti-vascular endothelial growth factor agents as treatment of wet age-related macular degeneration, the number of studies with the objective to understand the molecular mechanisms involved in the age-re lated macular degeneration genesis has increased. The importance of the nuclear factor e2-related factor 2 lies in its activation-derived proteins being involved in the maintenance of the redox balance and consequent prevention of degenerative macular disease. This article aims to present the characteristics of nuclear factor e2-related factor 2 and describe the main nuclear factor e2-related factor 2-activated antioxidant enzymes that contribute to the preservation of vision.

Análise cinética e cinemática da saída de bloco em natação de atletas deficientes visuais / Kinetic and kinemaic analysis of block start in swimming in visually impaired athletes

Objetivos: investigar e correlacionar a cinética e cinemática da saída de bloco em natação de atletas deficientes visuais e normovisuais. Métodos: foram comparados parâmetros de desempenho entre os nadadores de ambos os sexos. A amostra contou com 16 nadadores, sendo 4 cegos, 2 baixa visão e 10 normovisuais. Análise inferencial com teste Shapiro-Wilk, estatística inferencial teste T e, para correlação entre variáveis, o teste de Pearson, com nível de significância em 5%. Correlacionamos a variável dinamométrica, nas fases de tempo de bloco, tempo em 5 metros e tempo em 16 metros. Resultados: foram percebidas diferenças significativas de (0,030, 0,029 e 0,001), respetivamente, pois foram menores para os nadadores normovisuais. Na variável cinética, o pico de força resultante dos nadadores normovisuais foi, significativamente, maior (0,024). O ângulo de saída dos nadadores normovisuais foi também, significativamente, maior (0,030). Nas fases de tempo de reação, tempo de voo, força horizontal e vertical, ângulo de entrada e distância de voo, não apresentaram diferenças significativas. Observou-se uma correlação expressiva, entre as variáveis tempo de bloco e tempo em 5 metros (0,688); tempo de bloco e tempo em 16 metros (0,689); tempo em 5 metros e tempo em 16 metros (0,928); e o tempo de voo e ângulo de saída (0,941). O pico de força apresentou uma correlação significativa na maioria das variáveis do estudo com exceção do tempo de reação e o ângulo entrada. Conclusão: a ausência da visão acarreta na defasagem da performance e nos resultados em provas de natação de alto rendimento para deficientes visuais.

Objectives: to investigate and correlate the kinetics and kinematics of the starting block in swimming of visually impaired and visually impaired athletes. Methods: The method used was to compare performance parameters between swimmers of both sexes. The sample had 16 swimmers being 4 blind, 2 low vision and, 10 normovisuals. Inferential analysis with Shapiro-Wilk test, inferential statistics T-test, and for correlation between variables the Pearson's test, with a significance level of 5%. We correlated the dynamometric variable, in the phases of block time, time in 5 meters and time in 16 meters. Results: Resulting in significant differences of (0.030, 0.029, and 0.001, block time, 5 and 16 meters respectively) lower for the normovisual swimmers. In the kinetic variable, the peak force resulting from normal-vision swimmers was significantly higher (0.024). The departure angle of normal-vision swimmers was also significantly higher (0.030). In the phases of reaction time, flight time, horizontal and vertical force, entry angle and flight distance, there were no significant differences. An expressive correlation was observed between the variables block time and time in 5 meters (0.688); block time and time on 16 meters (0.689); time on 5 meters and time on 16 meters (0.928); and flight time and departure angle (0.941). The force peak showed a significant correlation in most of the variables under study except for the reaction time and the imput angle. Conclusion: the absence of vision leads to a lack of performance and results in high-performance swimming tests.

Differences in chromatic noise suppression of luminance contrast discrimination in young and elderly people.

Aging causes impairment of contrast sensitivity and chromatic discrimination, leading to changes in the perceptual interactions between color and luminance information. We aimed to investigate the influence of chromatic noise on luminance contrast thresholds in young and older adults. Forty participants were divided equally into Young (29.6 ± 6.3-year-old) and Elderly Groups (57.8 ± 6.6-year-old). They performed a luminance contrast discrimination task in the presence of chromatic noise maskers using a mosaic stimulus in a mosaic background. Four chromatic noise masking protocols were applied (protan, deutan, tritan, and no-noise protocols). We found that luminance contrast thresholds were significantly elevated by the addition of chromatic noise in both age groups (P < 0.05). In the Elderly group, but not the younger group, thresholds obtained in the tritan protocol were lower than those obtained from protan and deutan protocols (P < 0.05). For all protocols, the luminance contrast thresholds of elderly participants were higher than in young people (P < 0.01). Tritan chromatic noise was less effective in inhibiting luminance discrimination in elderly participants.

A Novel Velocity-Based Control in a Sensor Space for Parallel Manipulators.

It is a challenging task to track objects moving along an unknown trajectory. Conventional model-based controllers require detailed knowledge of a robot's kinematics and the target's trajectory. Tracking precision heavily relies on kinematics to infer the trajectory. Control implementation in parallel robots is especially difficult due to their complex kinematics. Vision-based controllers are robust to uncertainties of a robot's kinematic model since they can correct end-point trajectories as error estimates become available. Robustness is guaranteed by taking the vision sensor's model into account when designing the control law. All camera space manipulation (CSM) models in the literature are position-based, where the mapping between the end effector position in the Cartesian space and sensor space is established. Such models are not appropriate for tracking moving targets because the relationship between the target and the end effector is a fixed point. The present work builds upon the literature by presenting a novel CSM velocity-based control that establishes a relationship between a movable trajectory and the end effector position. Its efficacy is shown on a Delta-type parallel robot. Three types of experiments were performed: (a) static tracking (average error of 1.09 mm); (b) constant speed linear trajectory tracking-speeds of 7, 9.5, and 12 cm/s-(tracking errors of 8.89, 11.76, and 18.65 mm, respectively); (c) freehand trajectory tracking (max tracking errors of 11.79 mm during motion and max static positioning errors of 1.44 mm once the object stopped). The resulting control cycle time was 48 ms. The results obtained show a reduction in the tracking errors for this robot with respect to previously published control strategies.