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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Tele-oftalmologia em atenção primária / Tele-ophthalmology in primary care

Alexandre Chater Taleb 01 October 2009 (has links)
Introdução: As maiores causas mundiais de cegueira são preveníveis ou tratáveis. Mais de metade dos casos são devido a catarata ou erros de refração não corrigidos. Passo fundamental para a identificação precoce destas alterações, a triagem de acuidade visual pode ser feita por trabalhadores da saúde e educação habilitados para tal. A capacitação destas pessoas peca pela ausência de profissionais habilitados e disponíveis em número suficiente para esta tarefa. A possibilidade de aplicação de método eficaz de capacitação à distância por telemedicina pode ajudar o Brasil a alcançar as metas da OMS para o ano 2020. Métodos: Elaborou-se uma estratégia de educação à distância para trabalhadores de Equipes de Saúde da Família (ESF), por telemedicina, para o desenvolvimento de habilidade prática em área específica da saúde, aqui aplicada em oftalmologia. Aplicou-se a metodologia desenvolvida para a criação de um Instrumento Interativo de Capacitação em Triagem de Acuidade Visual (IICTAV). Baseado em objetos de aprendizagem sistematizados (em iconografia 3D e vídeos contextualizados) criados especificamente para este fim, associados a um simulador de casos, o IICTAV foi aplicado a trabalhadores da saúde de ESFs de todo o Brasil. Elaborou-se questionários para a avaliação da retenção de ganho de informação e da transformação desta informação em conhecimento, com aplicabilidade prática na correta triagem visual de pacientes. Resultados: Foram criados sete objetos de aprendizagem (OA), que podem ser utilizados isolados ou em conjunto. Associados a três simuladores de casos, os OAs foram aplicados em três cursos distintos, a 511 trabalhadores da ESFs, a maioria agentes comunitários de saúde, com 94,8% de acertos na avaliação conduzida. Conclusão: O IICTAV mostrou-se eficaz em habilitar os trabalhadores da saúde a ele expostos na técnica de avaliação da acuidade visual. A metodologia aplicada pode ser difundida por telemedicina para todo o Brasil, ampliando seu escopo para o desenvolvimento de outras habilidades práticas / Introduction: Most prevalent global causes of blindness are either preventable or treatable. More than fifty percent of blindness is due to cataract or unmet correction of refractive errors. Visual acuity screening is a major first step on the early detection of these conditions and may be performed by skilled health workers and teachers. Proper training of these workers lacks human resources both in quantity and availability. Being able to effectively teach health workers the skills to perform visual screening tests using telemedicine and distance education might help Brazil comply with WHO goals for 2020. Methods: A distance education strategy was planned for primary care health workers from Brazilian Family Health Teams to develop specific technical skills in health care. It was first applied to ophthalmology. The strategy was used to create an Interactive Visual Acuity Screening Skill Development Course (IVASSDC). The course was based on standardized learning objects (3D iconography and contextualization videos) who were specially designed and created as well as on a case simulator. The IVASSDC was applied to primary care health workers from all over Brazil. Questionnaires were created to address information retention and its development into knowledge that could allow an adequate visual acuity screening. Results: Seven learning objects and three case simulators were created to be used as a set or isolated. The set of educational tools was applied to 511 health workers from Brazilian Family Health Teams, most of them undergraduate community health agents. It proved effective in 94,8% of the evaluated participants. Conclusion: The Interactive Visual Acuity Screening Skill Development Course proved to be effective on the development of a specific skill in health workers from Brazil. The method can be spread through telemedicine to the whole country and can be applied to the development of other health techniques skills
72

Triagem de acuidade visual reduzida em uma unidade de atenção básica à saúde / Screening of reduced visual acuity in a basic health care unit

Carlos Fernando Adani Pereira 24 August 2018 (has links)
Introdução: No Brasil, os programas de prevenção dos distúrbios oculares têm se mostrado insuficientes. A consulta ambulatorial na Atenção Básica à Saúde poderia ser uma oportunidade para o rastreamento de agravos oculares. Objetivos: Determinar a prevalência e causas dos agravos oculares em crianças e adolescentes que utilizam os ambulatórios de Atenção Primária e avaliar a adequação existente nesses ambulatórios na aplicação de testes para a triagem visual. Casuística e Métodos: Estudo de corte transversal com 435 crianças e adolescentes que utilizavam os ambulatórios de Pediatria e Hebiatria do Centro Médico Social Comunitário Vila Lobato e que se submeteram à triagem visual utilizando-se a tabela de Snellen, um questionário e o Teste do Reflexo Vermelho do Olho. Resultados: Da amostra total, 70 (16%) dos indivíduos apresentaram distúrbios oculares e foram encaminhados ao oftalmologista, sendo que desses, 59 (84,2%) compareceram à consulta. O erro refracional foi detectado em 31 (52,5%) indivíduos examinados pelo oftalmologista, sendo o astigmatismo e a hipermetropia os mais comuns (18,6% e 15,2%, respectivamente). A miopia foi o erro refracional de menor prevalência encontrado, correspondendo a 1,7% dos indivíduos e 6,8% apresentaram outras patologias oculares. Conclusões: O estudo mostrou a prevalência de 16% de agravos oculares na população estudada. Verificou-se, também, que as consultas ambulatoriais em Atenção Primária à Saúde são uma oportunidade real para a aplicação de testes visuais. / Introduction: In Brazil, prevention programs for ocular disorders have proved insufficient. Outpatient consultation in Primary Health Care could be an opportunity for eye screening. Objectives: To determine the prevalence and causes of eye diseases in children and adolescents who use Primary Care outpatient clinics and to evaluate the suitability of these outpatient clinics in the application of tests for visual screening. Casuístic and Methods: A cross-sectional study with 435 children and adolescents using Pediatrics and Hebiatrics outpatient clinics at Vila Lobato Community Social Medical Center who underwent visual screening using the Snellen table, a questionnaire, and the Red Reflex Test Eye. Results: Of the total sample 70 (16%) of the pacients presented low visual acuity and were referred to the ophthalmologist, 59 (84.2%) of the pacients attended the consultation. The refractive error was detected in 31 (52.5%) of the pacients examined by the ophthalmologist, with astigmatism and hyperopia being the most common (18.6% and 15.2%, respectively). Myopia was the refractive error with the lowest prevalence found corresponding to 1.7% of the pacients, and 6.8% presented other ocular pathologies. Conclusions: The study showed the prevalence of 16% of ocular diseases in the study population. It has been realized that outpatient consultations in Primary Health Care are a real opportunity for the application of visual tests.
73

Estudo comparativo da densidade e topografia de neurônios de retinas de Philodryas olfesii e P. patagoniensis (serpentes, colubridae)

Hauzman, Einat 16 April 2009 (has links)
As serpentes são um grupo altamente diversificado, encontradas em praticamente todas as regiões do planeta, ocupando diferentes ambientes. Sua diversidade adaptativa indica a grande variabilidade dos órgãos sensoriais, adaptados ao hábitat e hábitos de cada espécie. Estudos sobre o sistema visual das serpentes são escassos e tem grande importância na compreensão de caracteres ecológicos, comportamentais e filogenéticos. Nos vertebrados as informações visuais são projetadas na retina e inicialmente processadas nessa camada neural, antes do processamento que ocorre no sistema nervoso central. Os tipos de células encontradas na retina, bem como sua densidade e distribuição variam entre as espécies e determinam especializações do sistema visual. Neste trabalho foi feita uma quantificaçao comparativa de fotorreceptores e neurônios da camada de células ganglionares (CCG) de duas espécies de serpentes colubrídeas diurnas, Philodryas olfersii e P. patagoniensis. Para tanto foram utilizadas técnicas de imunohistoquímica de opsinas e de marcação de Nissl. Serpentes adultas obtidas no Instituto Butantan foram anestesiadas com tiopental (30mg/kg) e sacrificadas com CO2. Os olhos foram enucleados e as retinas dissecadas e fixadas em paraformaldeido 4%. Um olho de cada serpente foi utilizado para fazer cortes radiais e testar diferentes tipos e concentrações de anticorpos. Para a preparação das retinas planas foram utilizados o anticorpo JH455, produzido em coelhos contra opsinas sensíveis aos comprimentos de onda curto de humanos (cones S) e o anticorpo JH492, produzido em coelhos contra opsinas sensíveis aos comprimentos de onda médio e longo de humanos (cones L/M). Foi utilizado anticorpo secundário biotinilado (gt -rb biot) e a revelação feita com estreptavidina acoplada a molécula florescente CY3. Os cortes radiais e as retinas planas foram observadas em microscópio fluorescente equipado com câmara digital conectada a microcomputador dotado de programa para captura de imagens. A partir de imagens da retina obtidas com espaçamento mínimo de 0,5 mm foram feitas as contagens das células e os mapas de isodensidade celular. A densidade média dos fotorreceptores foi semelhante nas duas espécies (11.183,1 ± 1.107,4 células/mm2 em P. olfersii e 11.531,2 ± 1.054,9 células/mm2 em P. patagoniensis), assim como a proporção dos diferentes tipos de cones (3% cones S e 83% cones L/M em P. olfersii, e 5% cones S e 85% cones L/M em P. patagoniensis). As densidades de células da CCG também foram semelhantes (10.117,5 ± 1.026 células/mm2 em P. olfersii e 9.834,9 ± 2.772,2 células/mm2 em P. patagoniensis). Entretanto, os mapas de isodensidade mostraram diferentes regiões de especialização. P. olfersii apresentou uma faixa horizontal e duas areas centralis de maior densidade celular, uma na região central e uma na região caudal, indicando a melhor acuidade visual nos campos de visão frontal e lateral, o que possivelmente auxilia na locomoção e forrageamento no extrato arbóreo. P. patagoniensis apresentou maior densidade celular na região ventral e rostral, indicando a maior acuidade no campo visual superior e posterior, auxiliando na percepção da aproximação de predadores e animais maiores, importante para a sobrevivência de serpentes terrestres e possivelmente para a percepção de presas localizadas em estrato arbustivo. / Snakes are a diversified group found in almost all regions of the planet, occupying different habitats, with exception to Polar Regions, a few islands and the deeper ocean waters. Its diversity indicates the high variability of sensory organs, which are adapted to the habits and habitats of each species. Studies about snakes visual system are scarce and have a great importance for the understanding of their ecology, behavior and phylogeny. In vertebrates the visual information is projected in the retina and initially processed in this neural tissue, before its processing in the central nervous system. The different kinds of cells present, as well as its density and distribution in the retina, vary between species and determinate specializations of the visual system. In this study we compared the density and distribution of photoreceptors and neurons of the ganglion cells layer (GCL) of two diurnal colubridae snakes, the arboreal Philodryas olfersii and the terrestrial P. patagoniensis, with opsins immunohistochemistry and Nissl staining. Adult snakes obtained in Instituto Butantan were anesthetized with thiopental (30mg/Kg) and the euthanasia was done with CO2. The eyes were enucleated and the retinas dissected and fixed in paraformaldeid 4%. One eye of each species was sectioned to test different antibodies and the counting for the determination of topographic distribution of density was made in flattened wholemount retinas. In the wholemounts retinas it was utilized the antibodies JH455 produced in rabbit against human S cone opsins and JH492 produced in rabbit against human L/M cone opsins. The photoreceptors density were similar in the two species (11,1831 ± 1,107.4 cells/mm2 in P. olfersii and 11,531.2 ± 1,054.9 cells/mm2 in P. patagoniensis), as well as the proportion of the different types of cells (3% S cones and 83% L/M cones in P. olfersii, and 5% S cones and 85% L/M cones in P. patagoniensis). The GCL cells density were also similar (10,117.5 ± 1,026 cells/mm2 in P. olfersii and 9,834.9 ± 2,772.2 cells/mm2 in P. patagoniensis). However, the isodensity maps showed different specializations regions. P. olfersii showed a horizontal streak and two areae (area centralis) with higher density, in the central and in the caudal regions, indicating a better visual acuity in the lateral and in the frontal visual field, what is possibly very important for locomotion and searching for preys (foraging) in the arboreal layer. P. patagoniensis showed a higher cell density in the ventral and rostral regions of the retina, indicating a better visual acuity in the superior and posterior visual field, what is important to perceive the approaching of predators and terrestrial animals and preys located in underbushes above the snake.
74

Objective quantification of sensory function using a battery of smartphone applications

Zarei, Kasra 01 May 2017 (has links)
Sensory deficits represent a major global public health problem. According to the World Health Organization, vision impairment affects an estimated 300 million people worldwide, and hearing impairment affects an estimated 360 million people worldwide. Consistent clinical evaluations for all individuals with sensory deficits cannot be practically realized due to the rising costs of healthcare, capital and labor limitations, and inaccessibility to healthcare due to a multitude of factors including proximity. The high prevalence of visual and hearing deficits can be lessened through consistent, comprehensive, at-home testing which can allow a larger amount of the affected and at-risk populations to be screened for abnormal function earlier and prior to permanent loss, and provide a wealth of patient-specific data that can be used to understand the time-scale of diseases and monitor the effectiveness of clinical interventions in unprecedented detail. While health-oriented smartphone applications exhibit a strong presence on the app stores, these applications are seldom vetted by expert scientists, engineers, and clinicians, and there are considerable opportunities for methodological improvements. The present work discusses the creation, calibration, and proof-of-concept, preliminary validation of a suite of psychophysical tests implemented as smartphone applications that can be utilized to rapidly and objectively quantify several functional sensory behaviors including flicker sensitivity, contrast sensitivity, visual acuity, and hearing-in-noise. Rigorous steps were undertaken to perform the necessary calibrations (a feat not routinely achieved by the creators of existing medical smartphone applications), and ensure the technical validity of the varying stimuli presented. Preliminary tests in the clinic have documented the potential of these tests to objectively provide numerous quantifications of, but not limited to, individual visual and hearing function, and variation between normal and abnormal subjects and function. The foundation laid by this work allows novel psychophysical tests to rapidly be implemented, vetted, and added to this battery of publicly and universally accessible medical smartphone applications.
75

Eye preference in human subjects : Consistency across measures and correlation with handedness

Bengtsson, Therése January 2010 (has links)
<p>The aim of the present study was to determine the distributions of and correlations between hand preference, visual acuity and eye preference through a series of tests in 50 males 50 females aged between 17 and 39 years. Handedness was determined through the Edinburgh handedness inventory questionnaire. The handedness distribution was: right-handed 90%, left-handed 1 %, and ambidextrous 9%. I found that 30 % had better visual acuity with their right eye, 39 % had better visual acuity with their left eye, and 31% had the same visual acuity with both eyes. 75.2% on average used their right eye in the battery of tests and 24.8% on average used their left eye. There were no statistically significant differences between the sexes or age groups with any of the measures. No correlation was found between eye preference and visual acuity or eye preference and hand preference among all subjects. No statistically significance between the sexes was found.</p>
76

Eye preference in human subjects : Consistency across measures and correlation with handedness

Bengtsson, Therése January 2010 (has links)
The aim of the present study was to determine the distributions of and correlations between hand preference, visual acuity and eye preference through a series of tests in 50 males 50 females aged between 17 and 39 years. Handedness was determined through the Edinburgh handedness inventory questionnaire. The handedness distribution was: right-handed 90%, left-handed 1 %, and ambidextrous 9%. I found that 30 % had better visual acuity with their right eye, 39 % had better visual acuity with their left eye, and 31% had the same visual acuity with both eyes. 75.2% on average used their right eye in the battery of tests and 24.8% on average used their left eye. There were no statistically significant differences between the sexes or age groups with any of the measures. No correlation was found between eye preference and visual acuity or eye preference and hand preference among all subjects. No statistically significance between the sexes was found.
77

Long-term outcome after cataract surgery : a longitudinal study

Lundqvist, Britta January 2009 (has links)
Background Cataract surgery is the most common surgical procedure carried out in the developed world and surgery volumes have increased considerably during the last decades. Various aspects of the surgical procedure, including surgical incision size and intraocular lens materials, have changed substantially, improving the safety and the quality of the outcome. Previous research has primarily focused on the visual function results with a short follow-up time. Long-term population-based studies, exceeding a few years, presenting visual functional results postoperatively, have not been published. Aims To determine the effects of cataract surgery on subjectively experienced visual function and visual acuity in a defined population, and compare the results between sub-groups, on a long-term basis. Methods In this prospective, population-based investigation, all patients with presenile and senile cataract (n=810), operated on during a one-year period (1997-98), at Umeå University Hospital were included. The frequency of cataract surgery at that time, was 5.2 per 1000 population studied. Visual acuity was tested and an eye examination was performed before surgery, 4-8 weeks postoperatively, and five and ten years after surgery. Subjective visual function was assessed using self-administered questionnaires (VF-14) at all occasions. Statistical evaluations comprised analyses of variance, Mann-Whitney U-test, chi-square test, multiple linear regression, a life-table calculation, and Cox’s proportional hazard model. Results Five years after cataract surgery, subjective and objective visual function remained stable in most patients. The most frequent cause of deterioration of visual acuity and decrease in VF-14 scores was agerelated macular degeneration (ARMD). Two thirds of the patients in the cohort were women. They were significantly older than the men and more often operated on both eyes. After adjustment for age and visual acuity, women cataract surgery patients assessed their visual function worse than men both before surgery and 4 months postoperatively. Five years after surgery these differences were no longer significant. At baseline, 13% of the patients were diabetics. At the five-year followup, subjective and objective visual function remained stable in most surviving diabetics, and the longitudinal visual function was not significantly worse compared with the non-diabetics. Ten years after surgery, 28% had received treatment for posterior capsular opacification (PCO). A significantly larger proportion of patients less than 65 years at surgery (37%) compared with those 65 years or older (20%) had been treated. Conclusions Most patients sustain their level of visual acuity and visual function also five and ten years after cataract surgery. Ocular co-morbidity, such as ARMD, is the major cause of longitudinally reduced visual function. Patients suffering from diabetes did not have a significantly worse visual function after five years. A surprisingly large proportion of patients had received treatment for PCO after ten years.
78

Face Processing Patterns of Persons with Asperger Syndrome : an Eye Tracking Study

Bram, Staffan, Lönebrink, Mikael January 2011 (has links)
One of the main diagnostic criteria for Asperger Syndrome is a severe social impairment (American Psychiatric Association [DSM-IV-TR] 2000), something that has often been connected to a more specific impairment in facial recognition. However, the main diagnostic tool (the DSM-IV-TR) has received much criticism during later years and is soon to be revised (Woodbury-Smith &amp; Volkmar 2009). Among other things, many researchers claim that the diagnosis should be complemented with a sliding scale of severity (Ring, Woodbury-Smith, Watson, Wheelright &amp; Baron-Cohen 2008). The use of facial information is central in the social interaction of humans, evident in the special patterns of visual scanning that people employ for facial stimuli (Yarbus 1967). Because of that, this symptom of Asperger Syndrome has become a high research priority. The impairment in facial recognition has been connected to a bias towards detail based processing (McPartland, Webb, Keehn &amp; Dawson 2010). A recent study also connects this to an unusually high visual acuity, which could result in a disposition to focus on small facial features. In the present study. facial stimuli were prepared to provoke memory conjunction errors. This type of memory error means that a person erroneously claims to recognize a face assembled by pieces of previously shown stimuli. If a person is more prone to do so, that would imply that he or she is more focused on details than on configural information (Danielsson 2006). Two groups were tested, one consisting of non-diagnosed adults and one of adults diagnosed with Asperger Syndrome. A test for visual acuity was administered, which was followed by a series of facial recognition tasks. Responses in the latter part were given with a computer mouse, and eye fixations were recorded using a head mounted eye-tracking device. Three hypotheses were formulated. First, persons with AS were expected to perform more poorly in all facial recognition tasks. Second, persons with AS were expected to make more conjunction errors than test group subjects. Finally, persons with AS were expected to display a mean visual acuity significantly higher than that of the test group. However, no significant differences emerged between the groups in relation to either of the hypotheses, and results could not be referred to flaws in the experimental setup. Therefore, these results are taken to display the heterogeneity of the Asperger Syndrome population, and possibly the importance of early training measures to compensate for social impairments.
79

Functional aspects of blur adaptation in human vision : a study of the mechanism of blur adaptation in human vision : its origin and scope evidenced using subjective and objective procedures

Mankowska, Aleksandra Maria January 2013 (has links)
Sensory adaptation to blur improves visual acuity under defocused conditions. This phenomenon has been successfully demonstrated using subjective measures of acuity and is known as blur adaptation. This study investigates aspects of the mechanism of blur adaptation in human vision using subjective and objective methods. Parafoveal visual acuity measured under defocused conditions demonstrates that blur adaptation is not limited to the fovea. The presence of the adaptive mechanism in the parafovea also suggests that the neural compensation that takes places under defocused conditions acts across a spatial range and is not limited to specific frequency bands. An evaluation of the contrast sensitivity function under defocus provides further evidence. Electrophysiological methods measure the effect of blur adaptation at the retina and at the visual cortex to provide objective evidence for the presence of the blur adaptation mechanism. Finally enhanced-depth imaging optical coherence tomography examines whether a period of prolonged defocus triggers any short-term changes in choroidal thickness in a similar manner to that reported in animal emmetropisation.
80

The Relationship Between 6/9 Distance Vision, Otitis Media with Effusion and Emergent Letter Name Knowledge

Casey, Maria Paula January 2013 (has links)
Background: There is a need for more well-controlled research on the relationship between vision and hearing limitations and emergent literacy to inform early literacy intervention. Two highly prevalent difficulties of early childhood, poor distance visual acuity and otitis media with effusion (OME), have been shown to be associated with literacy achievement. There is little research, however, on the relationship between these conditions and emergent literacy. Objective: The objective of this study was to assess the relationships between (1) distance visual acuity and emergent letter name knowledge, and (2) OME status and emergent letter name knowledge in children at school entry. Method: A prospective cohort of children (N=298) was recruited at school entry. Participants were aged 5, did not require special education for high needs and spoke a nationally recognized language of New Zealand. Distance vision and tympanometry testing was performed and a parent report of OME was obtained. The Wechsler Individual Test of Letter Name Knowledge and the Vocabulary and Block Design sub-tests of the Wechsler Intelligence Scale for Children were administered. Covariates of reading achievement were also measured. Results: Twenty three percent of children knew fewer than 4 letters at school entry, 31.9% had marginal distance visual acuity of 6/9 in one or both eyes and 37.2% had a history of ear infections and/or a B tympanometry test at school entry. Logistic regression tests demonstrated that both 6/9 vision (OR= 2.069, CI0.95=0.999-4.227) and OME status 10 (OR=1.846, CI0.95=1.034-3.297) were significantly associated with low letter name knowledge at school entry, controlling for covariates of emergent literacy. Another analysis showed that children with 6/9 vision and/or OME at school entry were also at greater risk for low letter knowledge (OR=2.187, CI0.95=1.067 – 4.484) than children with 6/6 vision and no OME at school entry. Conclusions: The results of the current study indicate that 6/9 distance vision and OME are risk factors for low letter name knowledge at school entry. These factors warrant greater consideration with regard to early literacy intervention, classroom teaching practices and future research.

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