Dissertação apresentada para obtenção do grau de Doutor em Engenharia Metalurgica, na Faculdade de Engenharia da Universidade do Porto, sob a orientação do Prof. Doutor Mário Barbosa

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L’atròfia geogràfica (AG) és la variant avançada de la degeneració macular associada a l’edat seca i es caracteritza per la presència d’àrees d’atròfia de l’epiteli pigmentari de la retina (EPR) que creixen progressivament, amb pèrdua secundària dels fotorreceptors i la coriocapilar adjacents. Actualment és una condició sense tractament. L’acumulació de lipofuscina a l’EPR, visualitzable clínicament mitjançant l’autofluorescència del fons d’ull (AFU) com a zones d’elevada autofluorescència, ha estat vinculada a la progressió de l’AG en alguns estudis. De fet, s’han descrit certs patrons (“fenotips”) en l’AFU basats en la distribució d’hiperautofluorescència que s’han associat amb taxes específiques de progressió de la malaltia. En aquesta Tesi hem fet un estudi clínic prospectiu per simplificar la complexa classificació dels patrons d’AFU i avaluar el paper de la hiperautofluorescència, un biomarcador de la lipofuscina, en la progressió de l’AG. / Geographic atrophy (GA) is the advanced form of dry age-related macular degeneration. It is characterized by large areas of retinal pigment epithelium (RPE) atrophy that grow progressively, with concomitant loss of photoreceptors and choriocapillaris. Currently, there is no treatment for this disorder. Lipofuscin build-up within the RPE, which is identifiable by fundus autofluorescence (FAF) as areas of increased autofluorescence, has been linked to GA progression in some studies. Actually, the distribution of hyperautofluorescence on FAF identified some patterns (“phenotypes”), which have been associated with specific rates of disease growth. We conducted a prospective clinical study to simplify the complex classification of FAF patterns and to determine the role of increased FAF, a biomarker of lipofuscin, in the progression of GA.

Tesi per compendi de publicacions. La consulta íntegra de la tesi, inclosos els articles no comunicats públicament per drets d'autor, es pot realitzar prèvia petició, a l'Arxiu de la UPC / The optical characterization of an intraocular lens (IOL) provides objective and quantitative information that is essential to fully understand its performance as an implant that replaces the crystalline lens in the human visual system. Additionally, it can be used to predict the performance of the new IOL designs. This thesis analyses the main sources of uncertainty in the calculation of the IOL power and the compensation of the residual refractive errors by using some unconventional degrees of freedom. The thesis focuses on the in vitro characterization of a variety of commercially available IOLs (monofocal, multifocal, spherical, aspherical, apodized, full-­-aperture, and of different materials, powers and additions) in optical bench. To this end, we have designed and implemented the necessary methods of measurement and an experimental setup that, according to the international standard regulation, reproduces the conditions of such implants in the human eye. We have developed a method to measure the energy efficiency of IOLs. This method has allowed us to explain the clinical results obtained in the evaluation of the stereoscopic acuity when using two tests based on different principles. The optical imaging quality of IOLs has been quantified through the experimental measurement of the modulation transfer function and the fringe visibility (contrast). We have developed and implemented a method to characterize some artifact, named halo, that can be perceived by those patients implanted with multifocal IOLs. Finally, all the experimental results have been used as a basis for the comparison of the IOL performances. / La caracterización óptica de las lentes intraoculares (IOLs del inglés Intraocular Lenses) proporciona una información objetiva y cuantitativa que es necesaria para comprender su funcionamiento como implante que sustituye al cristalino en el sistema visual humano. Además, permite predecir el rendimiento de los nuevos diseños. Dicha caracterización se debe llevar a cabo mediante pruebas in vivo en pacientes ya implantados así como con pruebas in vitro en banco óptico o mediante simulación teórica. Esta tesis analiza las fuentes de error en el cálculo de la potencia de las lentes intraoculares y la compensación de los errores refractivos residuales mediante el uso de grados de libertad no convencionales. Se centra, fundamentalmente, en la caracterización in vitro de una variedad de lentes comercialmente disponibles (monofocales, multifocales, esféricas, asféricas, apodizadas, no-­-apodizadas, y distintos materiales, potencias y adiciones) en un banco óptico. Para ello se ha diseñado y puesto a punto los métodos de medida, un montaje experimental que reproduzca las condiciones en las que las lentes se implantan en el ojo y de acuerdo con la normativa internacional. Se ha medido la calidad óptica a través de la Función de Transferencia de Modulación o la visibilidad de franjas (contraste). Se ha desarrollado e implementado un método para la cuantificación experimental de la eficiencia energética de los distintos modelos de IOLs. Este método ha servido para explicar algunos resultados clínicos obtenidos al evaluar la visión estereoscópica con dos tests con diferente principio de funcionamiento. Se ha desarrollado e implementado un método para caracterizar el halo que perciben algunos pacientes implantados con IOLs multifocales

The "Macular Projector" MAP, designed by us, is so effective, reliable and predictive as the Guyton-Minkowski PAMÒ and Retinometer Heine Lambda 100 in the assessment of potential visual acuity. The PAM has the advantage, above two equipments, allowing us to display the macular area when performing the test; as well as being an easy to use and comfortable to carry. The MAP is highly predictive, in patients with cataracts without associated diseases, with a low error rate and high reliability; without influence by the degree of cataract / El “Proyector Macular” MAP, diseñado por nosotros, es tan eficaz, fiable y predictivo como el Guyton-Minkowski PAMÒ y el Retinometro Heine Lambda 100 en la valoración de la Agudeza Visual Potencial. Con la ventaja, añadida sobre los otros dos, que nos permite visualizar el área macular, mientras realizamos la prueba; además de ser un equipo fácil de usar y cómodo de transportar. La predictibilidad, en pacientes con cataratas y sin patologías asociadas, para el MAP fue muy alta, con un rango de error bajo, sin verse influenciados por el grado de catarata; demostrándonos una alta fiabilidad

La visió és considerada un important indicador de salut i qualitat de vida tant de les persones com de les comunitats. El coneixement de les xifres de distribució de l’impediment visual poblacional, esdevé una eina de planificació imprescindible per l’elaboració de polítiques públiques de salut. L’objectiu principal de l’estudi, és pal·liar la situació de buit de dades referents a l’impediment visual a Catalunya i millorar l’efectivitat de la seva recol·lecció, per orientar la planificació de polítiques públiques i els protocols de les societats de prevenció de riscos laborals. Aquest estudi conclou en 4 principals resultats: a) proporciona per primera vegada, dades de l’impediment visual en adults a Catalunya que indiquen majors prevalences entre les dones, la gent gran i els col·lectius de pitjor posició socioeconòmica; b) introdueix noves preguntes de visió, conferint a l’Enquesta de Salut Catalunya la capacitat d’orientar la planificació de polítiques de salut; c) determina que en una població laboral, l’error refractiu corregit es concentra majoritàriament entre les dones i els treballadors no manuals; d) conclou que la utilització de correcció òptica és més comú entre els grups socialment més avantatjats i en determinades ocupacions amb majors requeriments de visió. / Vision is considered an important indicator of the health status and quality of life of both individuals and communities, and reliable data on the distribution of visual impairment is an essential planning tool for the development of public health policies. The overall aim of this study was to resolve the problem of lack of data on visual impairment in Catalonia, and to improve the effectiveness of data collection on visual health for public policy planning. This study produced four main findings: a) for the first time, it provides data on visual impairment in adults in Catalonia, showing a higher prevalence among women, seniors and people of lower socioeconomic status; b) it introduces new questions on vision, giving ESCA the capacity to influence health policy planning; c) it reveals that corrected refractive error in the working population is concentrated mainly among women and non-manual workers; and d) it confirms that the use of optical correction is more common among socially advantaged groups and in certain occupations with greater vision requirements

Made available in DSpace on 2014-06-11T19:23:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-11-03Bitstream added on 2014-06-13T20:50:36Z : No. of bitstreams: 1 bechara_kq_me_arafcf.pdf: 612220 bytes, checksum: 736809f7fd8297ed0cd47e2fcd8eedba (MD5) / Universidade Estadual Paulista (UNESP) / Um importante viés observado nos instrumentos de avaliação da dieta é a subnotificação ou o sub-registro do consumo de alimentos. Quando um indivíduo saudável e em balanço energético equilibrado relata um consumo energético muito baixo, implausível com a viabilidade biológica, este é identificado como um subnotificador ou sub-relatador. O objetivo deste estudo foi comparar seis diferentes abordagens para avaliação da subnotificação da ingestão energética entre obesas que aguardam na fila de espera para a cirurgia bariátrica, bem como verificar a associação da subnotificação com algumas características das voluntárias. Os resultados obtidos foram analisados em dois artigos científicos, sendo que o primeiro foi focado na comparação de diferentes abordagens para avaliar a subnotificação e o segundo se destina aos fatores associados à subnotificação na amostra. Participaram do estudo 100 candidatas à cirurgia da obesidade da Clínica Bariátrica de Piracicaba, localizada no interior do estado de São Paulo, Brasil. Dados como idade, cor, estado civil, grau de escolaridade, hábito de fumar, consumo de bebida alcoólica e alteração de peso recente foram obtidos por meio de uma entrevista. Para divisão das participantes em classes econômicas foi utilizado o questionário da Associação Brasileira de Empresas de Pesquisa. Medidas antropométricas e de composição corporal também foram coletadas. A subnotificação do consumo alimentar foi avaliada baseada na diferença entre ingestão energética relatada (IErel) e requerimentos energéticos calculados: gasto energético de repouso (GER) e o nível de atividade física (NAF). Foram adotadas seis abordagens para definição de pontos de corte levando... / An important bias observed in diet assessment instruments is food intake underreporting or under-recording. When a healthy individual in a balanced energy state reports a very low energy intake, implausible with biological viability, this individual is called an underreporter. The objective of this study was to compare six different approaches for assessing energy intake underreporting in obese women in the waiting line for bariatric surgery, as well as to verify the association between underreporting and some characteristics of these women. The results were analyzed in two scientific articles. The first article focused on the comparison of different approaches for assessing underreporting and the second article focused on the factors associated with underreporting by the studied sample. The sample consisted of 100 women in the waiting line for bariatric surgery at the Bariatric Clinic of Piracicaba, a city located in upstate São Paulo, Brazil. An interview was used for collecting the following data: age, skin color, marital status, education level, smoking status, intake of alcoholic beverages and recent weight changes. The questionnaire created by the Brazilian Market Research Association (Associação Brasileira de Empresas de Pesquisa) was used to determine the socioeconomic classes of the participants. Anthropometric measurements and body composition data were also collected. Underreporting was determined by the difference between reported energy intake (rEI) and calculated energy requirements: resting metabolic rate (RMR) and physical activity level (PAL). Six approaches were used for defining the cut-off points, taking into account the variances of the components of the equation rEI:RMR = PAL, as a function of assumed PAL, number of subjects (n) of the sample and measured or estimated... (Complete abstract click electronic access below)