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- Binocular vision and balance measurement and analysisPublication . Oliveira, Manuel; Mendanha, Luís; Pereira, Leonor MonizAn individual’s ability to see and function visually is determined largely by the relative contributions of a number of underlying components of vision designated as visual abilities. These visual abilities are: acuity, visual field, motility, brain functions, and light and color reception others consider also contrast, accommodation, and binocular vision. It is through the conjugated movement of the two eyes that we can fix and pursue one object. The ocular movements and the binocular vision are linked and they are influenced mutually. The measurement device most often used for measuring eye movements is commonly known as an eye tracker. Objective: To characterize the signal having into account the type of ocular movement that means saccadic and fixation movements. Habitually, the objective of the analysis is to locate regions where the signal brusquely changes position, indicating the end of the fixation and the beginning of the saccade. Later the signal assumes a stationary position, indicating the beginning of a new fixation.
- Eye tracker, binocular vision and oculomotor balance: exploratory studyPublication . Mendanha, Luís; Oliveira, Manuel; Pereira, Leonor MonizIntroduction: It is not clearly determined if vision provokes movement or if it is movement itself that provokes and propitiates the visual search and exploration. Lack of concentration phenomena, localization mistakes, and excessive visual effort is associated with binocular function alterations and therefore they can restrict or even turn the daily routine in the different areas of human activity impossible. The study of visual tracking will enable us to characterize the fixation and saccadic movement. Aim of the study: The study aims to analyze the eye tracking of individuals with alterations of oculomotor balance or of the binocular vision, by comparing them with individuals without these alterations.
- Caracterização da direcção do olhar em indivíduos com e sem insuficiência de convergênciaPublication . Mendanha, Luís; Silva, Leonor Moniz PereiraA eficácia do nosso sistema visual influencia o modo como recolhemos e processamos a informação. Uma visão ineficiente pode provocar uma menor capacidade no desempenho de algumas tarefas. Uma das situações mais comuns, onde isso se verifica é a insuficiência de convergência. Assim, pretendemos investigar a existência de diferenças significativas, durante a fixação e perseguição de um alvo, em indivíduos com e sem insuficiência de convergência. Utilizámos uma amostra composta por adultos jovens, distribuídos por dois grupos, um formado por indivíduos com visão binocular normal e outro por indivíduos com insuficiência de convergência, ambos com 26 participantes. Os resultados obtidos apontam para uma perda de qualidade relativamente à fixação e perseguição visual, nos indivíduos com insuficiência de convergência e parecem sugerir também uma maior estabilidade da fixação e um movimento sacádico mais preciso nos indivíduos com visão binocular normal. Deste modo, a correcção da insuficiência de convergência é fundamental para a existência de um conforto visual adequado de modo a permitir um normal desempenho nas diferentes actividades diárias, evitando-se assim, repercussões negativas na qualidade de vida dos indivíduos.
- Eye tracker, binocular vision and oculomotor balance: exploratory studyPublication . Mendanha, Luís; Oliveira, Manuel; Pereira, Leonor MonizWe have analysed the vision direction with the Eye Tracker System ASL-model 504 of individuals with alterations of oculomotor balance or binocular vision, comparing them with individuals without those kinds of alterations. The sample was composed of 40 individuals, men, and women, with ages between 18 and 23. They were distributed as follows: individuals with normal binocular vision (NBV) in binocular and monocular conditions and with convergence insufficiency (CI). Significant differences were found between the studied groups, pointing out that the absence of binocularity, as the existence of convergence insufficiency, entails clearly a quality loss of the visual pursuit.
- Binocular vision and balance measurement and analysisPublication . Oliveira, Manuel; Mendanha, Luís; Pereira, Leonor MonizAn individual's ability to see and function visually is determined largely by the relative contributions of a number of underlying components of vision designated as visual abilities. These visual abilities are: acuity, visual field, motility, brain functions, and light and colour reception others consider also contrast, accommodation, and binocular vision. The efficacy of our visual system influences the way we collect and process information. It is through the conjugated movement of the two eyes that we can fix and pursue one object. The ocular movements and the binocular vision are linked and they are influenced mutually. The measurement device most often used for measuring eye movements is commonly known as an eye tracker. In order to characterize the mechanisms of fixation and persecution and the way how binocular vision influences them, we use in our study the Eye Tracking System-ASL 504, because allows an evaluation next to the natural conditions. Our sample was composed by young adults, distributed in two groups, one formed by individuals with normal binocular vision evaluated in two different conditions (binocular and monocular) and another one by individuals with convergence insufficiency, both with 24 participants. The individuals observe a small target, moving in four directions (left-right; right-left; up-down; down-up). The selected variables were: the mean duration of the fixation and mean saccadic amplitudes. The study of normality seems to indicate that the Eye Tracker is an efficient system for the study of ocular movements (fixation and pursuit). The eye-tracking system that we use showed good discrimination for the selected variables. We think that this study shows the important contribution that eye tracking can give in the analysis, of the functional alterations of binocular vision because allows us to evaluate them in conditions very next to reality.