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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.
1

Adaptometria de escuro para estudos de retina

Stefenon, M?rcio 19 December 2013 (has links)
Made available in DSpace on 2015-04-14T13:56:31Z (GMT). No. of bitstreams: 1 458958.pdf: 7355419 bytes, checksum: 8a2fa20967c4240f1bb187644d3207a4 (MD5) Previous issue date: 2013-12-19 / Vision is one of the most important senses of man. Many diseases that affect the sense of vision are related to the retina. Some of these diseases specifically affecting the photoreceptors, light-sensitive cells that is the first stage of vision. The examinations of dark adaptation have motivated interest in the study of mechanisms of retinal diseases. This exam directly accesses the functions of the photoreceptors by noninvasive methods. The technique consists in measuring the time to recovery of sensitivity of the retina after exposing the retina to a controlled amount of light. The dark adaptometry equipment is used to monitor the response of these cells to a light stimulus and then reveal some deficiency in the operation. This work describes the procedures, calculations, measurements and verifications necessary for the calibration of an existing dark adaptometer. This equipment was developed in the Image Laboratory at PUCRS, led by Professor Dario Azevedo, Ph.D. from a modified fundus camera. This dark adaptometer is able to test localized regions of the retina, while visualizing the regions of interest, and therefore compensating for any eye movements. For calibration of dark adaptometer, various calculations based on literature review was conducted. After using instruments such as spectrometer, radiometer, and light meter luminometer dark adaptometer was calibrated. The operation of each block that makes up this instrument was checked. Measurements of illuminance values of the light stimulus, retinal luminance attenuation of dark adaptometer, attenuation imposed by optical fiber, was observed throughout the range of attenuation filters (0 dB to 60 dB), also checked the operation of the wheels were made and a shutter that filters are controlled by the motor steps. The dark adaptometer met all specifications, i.e., the values set in the calculations in this work has been achieved. / A vis?o ? um dos mais importantes sentidos do homem. Muitas doen?as que afetam o sentido da vis?o est?o relacionadas com a retina. Algumas dessas doen?as afetam especificamente os fotorreceptores, c?lulas sens?veis ? luz, que ? o primeiro est?gio da vis?o. Os exames de adapta??o ao escuro t?m motivado o interesse no estudo de mecanismos de doen?as de retina. Esse exame acessa diretamente as fun??es dos fotorreceptores por m?todos n?o invasivos. A t?cnica consiste, em medir o tempo de recupera??o da sensitividade da retina, depois de expor a retina a uma quantidade controlada de luz. Um equipamento de adaptometria ao escuro ? utilizado para monitorar a resposta destas c?lulas a um est?mulo luminoso e ent?o revelar alguma defici?ncia no funcionamento. Neste trabalho, est?o descritos os procedimentos, c?lculos, medidas e verifica??es necess?rias para a calibra??o de um adapt?metro de escuro j? existente. Este equipamento foi desenvolvido no Laborat?rio de Imagens da PUCRS, liderado pelo professor Dario Azevedo Ph.D. a partir de uma c?mera de fundus modificada. Este adapt?metro de escuro ? capaz de testar, de forma localizada, regi?es da retina permitindo, a crit?rio do examinador testar e mapear exclusivamente as regi?es que forem do seu interesse e compensar eventuais movimentos oculares. Para a calibra??o do adapt?metro de escuro, foi realizados diversos c?lculos com base na revis?o bibliogr?fica. Ap?s, utilizando instrumentos como espectrofot?metro, espectroradi?metro, lux?metro e luminanc?metro o adapt?metro de escuro foi calibrado. Foi verificado o funcionamento de cada bloco que comp?e este instrumento. Foram realizadas as medidas dos valores de ilumin?ncia do est?mulo luminoso, lumin?ncia retinal, atenua??es do adapt?metro de escuro, atenua??o impostas pela fibra ?ptica, foi verificado toda a faixa de atenua??o dos filtros (0 dB at? 60 dB), tamb?m verificado o funcionamento das rodas de filtros e do shutter que s?o comandados pelos motores de passos. O adapt?metro de escuro atendeu todas as especifica??es, ou seja, os valores definidos nos c?lculos neste trabalho foram atingidos.

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