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Authors
Abstract(s)
Introdução: A técnica do Olhar Preferencial é usada para medir a acuidade visual em indivíduos que tenham dificuldade em verbalizar respostas, como por exemplo, em indivíduos com deficiência intelectual. Esta técnica pode ser aplicada objetivamente através de uma plataforma informática desenvolvida. Tradicionalmente na aplicação desta técnica são usadas redes espaciais com varias frequências. No entanto, estas redes podem ser substituídas por optótipos mais complexos como as figuras LEA. A utilização de figuras com um filtro passa-alto “vanishing”, tem como vantagem incrementar a sensibilidade da medida à desfocagem. Para além disso, os autores consideram que as figuras LEA podem aumentar o interesse do observador no teste.
Objetivo: O objetivo deste estudo é medir a acuidade visual numa população com deficiência intelectual de maneira objetiva através de uma plataforma informática. Pretende-se ainda averiguar a precisão dos resultados obtidos com a acuidade visual medida usando um teste de correspondência de símbolos.
Métodos: Esta dissertação está dividida em três experiências. Na primeira experiência, que consistia em avaliar se a acuidade visual alterava com o tempo de exposição aos estímulos, participaram 5 indivíduos compensados de modo a atingir uma acuidade visual de 0,00 logMAR ou melhor. A segunda experiência contou com dois indivíduos, devidamente compensados, sendo que, esta experiência tinha como objetivo avaliar a variabilidade de acuidade visual para os diferentes estímulos criados. Na terceira experiência, existiram dois grupos, os controlos, que englobou vinte indivíduos, sem qualquer tipo de anomalia intelectual, com erro refrativo não compensado e os casos, que englobou um total de trinta e um indivíduos com algum tipo de deficiência intelectual, com erro refrativo não compensado. Esta terceira experiência teve como objetivo avaliar o desempenho da plataforma informática criada numa população com deficiência intelectual
Resultados: A primeira experiência demonstrou que existe uma relação entre a acuidade visual e o tempo de exposição ao estímulo visual, existindo um ganho de AV com o aumento do tempo de exposição até atingir um ponto de saturação. Na segunda experiência foi possível concluir que existe variabilidade entre os diferentes estímulos visuais, no entanto, esta variabilidade é menor entre os estímulos do mesmo conjunto de optótipos, principalmente nos optótipos LEA em que a variabilidade é muito reduzida. Na terceira e derradeira experiência foi possível concluir que a plataforma desenvolvida e adaptada permite uma avaliação fiável da AV. Por outro lado, numa população com deficiência intelectual, o sistema também funciona bem, ou seja, os indivíduos conseguem completar o teste mantendo a cabeça no devido lugar, no entanto, os valores obtidos para a AV tem uma fiabilidade muito reduzida em indivíduos com deficiências mais profundas, dado que, em casos que a deficiência é leve, os resultados podem ser considerados fiáveis.
Conclusões: O teste do olhar preferencial corrido na plataforma informática funciona bastante bem na população com deficiência intelectual, na medida em que estes indivíduos conseguem completar o teste sem dificuldade, sem interrupções e sem quererem abandonar o mesmo. Em indivíduos com grau de deficiência leve, os valores de AV extraídos são considerados fiáveis. Existem, no entanto, distrações ao nível do olhar fazendo com que os valores de AV extraídos pelo teste tenham uma fiabilidade muito reduzida, em especial, para graus mais profundos de deficiência pelo qual, existem melhorias a fazer no método de medição da AV. Podem ainda ser feitas algumas melhorias no teste em si de modo a captar com mais facilidade a atenção deste tipo de população.
Introduction: The preferential looking method is used to assess the visual acuity in people who struggle to verbalize their answers, like for example, individuals with intellectual disability. This method can be applied trough objective techniques, using an informatic platform. Usually this method uses sinusoidal waves, with different frequencies. However, we can replace this stimulus with more complex stimulus, like LEA optotypes. The utilization of this figures with a high-pass filter, allows some advantages like increasing the defocus sensibility. Besides that, the authors consider that this substitution can make this method much more interesting to the observer. Objective: The objective of this study is to measure visual acuity in a population with Intellectual Disability using an informatics platform that runs a Preferential Looking teste. We also pretend to ascertain the precision of the results obtained with the visual acuity values obtained through the use of optotypes with symbols. Methods: This study was divided into three experiments. On the first one, the main gold was to assess if the exposition time had effect on the visual acuity, being that, five persons participated in this experiment, all of them were compensated in order to obtain a 0,00 logMAR score or better. The second one, consisted in evaluating the variability of the different visual stimulus created. In this case, only three individuals completed the experience, being that, all of them were also compensated in order to obtain a 0,00 logMAR score or better. In the last one, the aim was to evaluate the performance of the platform when used in a population with Intellectual Disability. Results: The first experiment showed that a relation between visual acuity and exposition time exists, being that, with the increase of the exposition time, the visual acuity keeps getting better until it reaches a saturation point. In the second one, it was possible to conclude that variability between the different visual stimuli exists, however, this variability is smaller when the opotypes belong to the same group. The variability reaches smaller values with the LEA optotypes. In the third and last experiment it was possible to conclude that the developed platform allows to obtain a reliable visual acuity value in a population without any kind of intellectual disability, giving results with a good reliability. On the other hand, in the population with intellectual disability, the platform also works well, that is, they keep their head where it should be and most of them complete the test with success, however, the results for visual acuity obtained with this population have low reliability for more severe conditions, since that, in cases that are less severe, it was also possible to obtain reliable visual acuity values.Conclusions: The preferential looking test that runs in the informatics platform works well in a population with intellectual disability, because a large part of the population submitted to the test was able to complete it without difficulty, interruptions or will to leave the test. If the intellectual disability level is low, the visual acuity values that are given from the test are reliable. There are, however, some distractions when it comes to looking to the visual stimulus, and due to that, the visual acuity results show low reliability, especially in individuals that have more severe conditions, whereby, there are some improvements to do in the method of measuring the visual acuity value. Some improvements can also be done to the test, so it can be more appellative to this kind of population.
Introduction: The preferential looking method is used to assess the visual acuity in people who struggle to verbalize their answers, like for example, individuals with intellectual disability. This method can be applied trough objective techniques, using an informatic platform. Usually this method uses sinusoidal waves, with different frequencies. However, we can replace this stimulus with more complex stimulus, like LEA optotypes. The utilization of this figures with a high-pass filter, allows some advantages like increasing the defocus sensibility. Besides that, the authors consider that this substitution can make this method much more interesting to the observer. Objective: The objective of this study is to measure visual acuity in a population with Intellectual Disability using an informatics platform that runs a Preferential Looking teste. We also pretend to ascertain the precision of the results obtained with the visual acuity values obtained through the use of optotypes with symbols. Methods: This study was divided into three experiments. On the first one, the main gold was to assess if the exposition time had effect on the visual acuity, being that, five persons participated in this experiment, all of them were compensated in order to obtain a 0,00 logMAR score or better. The second one, consisted in evaluating the variability of the different visual stimulus created. In this case, only three individuals completed the experience, being that, all of them were also compensated in order to obtain a 0,00 logMAR score or better. In the last one, the aim was to evaluate the performance of the platform when used in a population with Intellectual Disability. Results: The first experiment showed that a relation between visual acuity and exposition time exists, being that, with the increase of the exposition time, the visual acuity keeps getting better until it reaches a saturation point. In the second one, it was possible to conclude that variability between the different visual stimuli exists, however, this variability is smaller when the opotypes belong to the same group. The variability reaches smaller values with the LEA optotypes. In the third and last experiment it was possible to conclude that the developed platform allows to obtain a reliable visual acuity value in a population without any kind of intellectual disability, giving results with a good reliability. On the other hand, in the population with intellectual disability, the platform also works well, that is, they keep their head where it should be and most of them complete the test with success, however, the results for visual acuity obtained with this population have low reliability for more severe conditions, since that, in cases that are less severe, it was also possible to obtain reliable visual acuity values.Conclusions: The preferential looking test that runs in the informatics platform works well in a population with intellectual disability, because a large part of the population submitted to the test was able to complete it without difficulty, interruptions or will to leave the test. If the intellectual disability level is low, the visual acuity values that are given from the test are reliable. There are, however, some distractions when it comes to looking to the visual stimulus, and due to that, the visual acuity results show low reliability, especially in individuals that have more severe conditions, whereby, there are some improvements to do in the method of measuring the visual acuity value. Some improvements can also be done to the test, so it can be more appellative to this kind of population.
Description
Keywords
Deficiência Intelectual Erro Refrativo Olhar Preferencial Optótipos ?Vanishing?