No / The purpose of this research was to correlate in vivo spatial and spectral morphologic changes of short- to long-pulse 532 nm Nd:YAG retinal laser lesions using Fourier-domain optical coherence tomography (FD OCT), autofluorescence (AF), fluorescein angiography (FA), and multispectral imaging. Ten eyes with treatment-naive preproliferative or proliferative diabetic retinopathy were studied. A titration grid of laser burns at 20, 100, and 200 milliseconds was applied to the nasal retina and laser fluence titrated to produce four grades of laser lesion visibility: subvisible (SV), barely visible (BV, light-gray), threshold (TH, gray-white), and suprathreshold (ST, white). The AF, FA, FD-OCT, and multispectral imaging were performed 1 week before laser, and 1 hour, 4 weeks, and 3 and 6 months post-laser. Multispectral imaging measured relative tissue oxygen concentration. Laser burn visibility and lesion size increased in a linear relationship according to fixed fluence levels. At fixed pulse durations, there was a semilogarithmic increase in lesion size over 6 months. At 20 milliseconds, all grades of laser lesion were reduced significantly in size after 6 months: SV, 51%; BV, 54%; TH, 49%; and ST, 50% (P < 0.001), with retinal pigment epithelial proliferation and photoreceptor infilling. At 20 milliseconds, there was healing of photoreceptor inner segment/outer segment junction layers compared with 100- and 200-millisecond lesions. Significant increases in mean tissue oxygenation (range, four to six units) within the laser titration area and in oxygen concentration across the laser lesions (P < 0.01) were detected at 6 months. For patients undergoing therapeutic laser, there may be improved tissue oxygenation, higher predictability of burn morphology, and more spatial localization of healing responses of burns at 20 milliseconds compared with longer pulse durations over time / Optimedica Corp., the Manchester Academic Health Sciences Centre, and the NIHR Manchester Biomedical Research Centre. JD was funded by a College of Optometrists PhD Studentship, United Kingdom.

L’impact laser obtenu avec les systèmes actuels de photocoagulation laser de la rétine n’est pas maitrisé. L’enjeu est d'obtenir un confinement 3D de l'impact laser, c’est-à-dire de contrôler son positionnement et son extension, pour éviter de porter atteinte aux couches saines de la rétine. Un tel confinement pourrait être réalisé si l’on disposait d’un système laser plus ouvert et d’un dispositif permettant de corriger en temps réel les aberrations de l'œil. L’optique adaptative permet une telle correction ; cette technique est utilisée depuis une vingtaine d’années dans le domaine du diagnostic (imagerie). Cependant, sa mise en œuvre pour des applications thérapeutiques, telles que la photocoagulation laser, nécessite encore d’en améliorer la robustesse : alors qu’en imagerie il suffit de reprendre une image si la précédente est mauvaise, le confinement de l’impact laser doit être assuré en permanence durant toute la procédure chirurgicale. Le but de la thèse est de guider le développement ultérieur d’un système d’optique adaptative médical visant à assister un système de photocoagulation laser de la rétine. Le dimensionnement d’un tel système doit s’appuyer sur une solide connaissance des aberrations oculaires. Ainsi, une étude hautement résolue temporellement et spatialement des aberrations dynamiques de l’œil de grande ampleur a été réalisée et de cette étude, des conclusions sur le dimensionnement d’un système d’optique adaptative pour l’œil ont été tirées. Par ailleurs, un banc de test d’optique adaptative haute cadence a été conçu et intégré pour se confronter aux problèmes pratiques que pose la mise en place d’un système d’optique adaptative pour l’œil. / The laser lesion delivered by current retinal photocoagulation laser systems is not well controlled. The issue is to get a better confinement of the laser lesion that is to control the size of the laser lesion as well as the laser lesion positioning in the retina, in order to prevent any retinal damage. Such a confinement could be reached if the laser system featured a higher numerical aperture and was associated with a real-time correction of the aberrations of the eye. Adaptive optics gives access to such a correction; this technique has been used for the past twenty years for diagnosis (retinal imaging). However, further work is still to be achieved to improve the robustness of current adaptive optics systems before implementing adaptive optics in therapeutic systems, in particular in retinal laser photocoagulation systems. Indeed, unlike imaging where the acquisition can be repeated as many times as necessary, the confinement of the laser lesion must be maintained over time during the whole laser treatment. In this thesis, we provide guidance for the future design of an adaptive optics system for retinal photocoagulation. Such a design has to rely on a thorough knowledge of the ocular aberrations to correct. Thus, a highly temporally as well as spatially resolved aberrometry study on a large population was performed and conclusions on the design of an adaptive optics system for the eye were drawn from this study. Besides, a test bench was designed and set up to face the practical problems coming with the implementation of an adaptive optics system for the eye.

No description available.

No description available.

En esta tesis estudiamos la población total de las células ganglionares de la retina (CGR) en rata y ratón, y desarrollamos un modelo experimental de hipertensión ocular mediante fotocoagulación láser. La población de CGR proyecta masivamente a los colículos superiores. Se observa una estría visual en la retina dorsal donde se encuentra las densidades más altas de CGR. La pequeña población de CGR ipsilateral se distribuye mayoritariamente en la periferia de la retina temporal. El aumento de la presión intraocular induce una compresión de los axones en la cabeza del nervio óptico que provoca una alteración del transporte axonal retrógrado, que induce una degeneración sectorial localizada y difusa de las CGR, preferentemente en la retina dorsal, así como de sus axones. La pérdida selectiva de las CGR en la capa de CGR, sugiere que la causa de la muerte de las CGR no se debe a una isquemia retiniana. / In this thesis we have studied the total population of retinal ganglion cells (RGCs) in rat and mouse, and developed an experimental model of ocular hypertension by laser photocoagulation. The RGC population projects massively to the superior colliculi. There is a visual streak in the dorsal retina where the highest densities of RGCs are found. The small population of ipsilateral RGCs is distributed mainly in the periphery of the temporal retina. The increase of intraocular pressure induces a compression of the axons at the optic nerve head that causes a disturbed retrograde axonal transport, inducing a localized, diffuse and sectorial degeneration of RGCs and their axons, preferably in the dorsal retina. The selective loss of RGCs in the RGC layer, suggests that the cause of the RGC loss is not due to retinal ischemia.

Submitted by Ana Lúcia Torres (bfmhuap@gmail.com) on 2017-09-29T23:29:42Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) DISSERTAÇAO RENATO GOMES.pdf: 1085453 bytes, checksum: 52c34bec90105d63a6d951a99405c02d (MD5) / Approved for entry into archive by Ana Lúcia Torres (bfmhuap@gmail.com) on 2017-09-29T23:31:18Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) DISSERTAÇAO RENATO GOMES.pdf: 1085453 bytes, checksum: 52c34bec90105d63a6d951a99405c02d (MD5) / Made available in DSpace on 2017-09-29T23:31:18Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) DISSERTAÇAO RENATO GOMES.pdf: 1085453 bytes, checksum: 52c34bec90105d63a6d951a99405c02d (MD5) Previous issue date: 2012 / Santa Casa de Misericórdia de Vitória. Escola Superior de Ciências / Objetivo: Comparar a acuidade visual em pacientes com oclusão de ramo de veia central da retina (ORVCR), antes e após tratamento combinado de injeção intravítrea de bevacizumabe com fotocoagulação a laser. Método: Uma análise retrospectiva de pacientes com ORVCR que foram tratados com injeção intravítrea de bevacizumabe (1,25mg/0,05ml) seguida de fotocoagulação a laser na área afetada. Os pacientes passaram por avaliação oftalmológica completa, incluindo medida da acuidade visual (AV) com tabela de Snellen no momento do diagnóstico e nas visitas de acompanhamento. Foram excluídos prontuários incompletos ou com erros de preenchimentos e prontuários de pacientes com outras alterações oculares que pudessem interferir nas medidas da acuidade visual. Resultados: Foram analisados 26 prontuários (11 homens e 15 mulheres) de pacientes com diagnóstico de ORCVR no Serviço de Oftalmologia da Santa Casa de Vitória durante todo o ano de 2010. Todos os pacientes foram acompanhados por 6 meses. O tempo médio de baixa da acuidade visual antes do diagnóstico foi de 21,2 dias (1-140 dias). Com acuidade visual inicial média de 0.74 LogMAR (p<0.001) e com melhora média após 6 meses do início do tratamento para 0.32 LogMAR (p<0.001), representando assim um ganho médio de 0.42 LogMAR (p<0.001) ou 19.4 letras de ETDSR (p<0.001). Foram utilizados testes não paramétricos a fim de permitir mais generalização aos resultados evitando a premissa de normalidade. O teste de Wilcoxon foi utilizado para verificar a variação da acuidade visual inicial e final. Não foram observadas complicações oculares ou sistêmicas durante o acompanhamento. Conclusão: Houve melhora da acuidade visual comparando pré o pós tratamento combinado de injeção intravítrea de bevacizumabe com fotocoagulação a laser. A estabilidade do ganho obtido no tratamento combinado com a ausência de complicações demonstra o potencial do uso combinado de injeção intravítrea de bevacizumabe com fotocoagulação a laser no tratamento de ORVCR / Purpose: Compare the visual acuity (VA) in patients with branch retinal vein occlusion (BRVO), before and after been treated with a combination of intravitreal injection of bevacizumab followed by laser photocoagulation. Method: A retrospective analyses of patients with BRVO that underwent a treatment of intravitreal injection of bevacizumab (1,25mg/ 0,05ml) followed by laser photocoagulation on the affected area. Patients went through complete eye examination, including visual acuity measure with Snellen chart on the diagnostic visit and on the follow-ups. Uncompleted and miswritten charts ware excluded as well as charts of patients with others ocular affections that could interfere in visual acuity measure Results: 26 charts (11 male and 15 female) of patients with BRVO from the Ophthalmological Department of Santa Casa de Misericórdia Hospital during 2010 were analyzed. All patients underwent a 6 months follow-up. The average VA loss before diagnostics was 21.2 days (1-140). The average VA was 0.74 LogMAR (p<0,001) with improvement after 6 month of treatment to 0.32 LogMAR (p<0,001), representing a average gain of 0.42 LogMAR (p<0,001) or 19.4 ETDRS letters (p<0,001). Non parametric tests ware used to allow more generalization of the results avoiding normality assumption. The Wilcoxon was applied to verify de VA variation during de study. No eye or systemic complications ware observed during the study. Conclusions: Visual acuity gain occur comparing before and after treatment with bevacizumab intravitreal injection followed by laser photocoagulation. The stability of the gain combined with a absences of complications demonstrate de potential of combined intravitreal bevacizumab and laser photocoagulation in patients with BRVO