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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.
11

Surgical outcomes of recurrent macular hole

Sharifzadeh, Arya 08 April 2016 (has links)
Idiopathic macular hole is a disease of the eye with unknown cause, but a pathology that, over the course of several decades of investigation by clinicians and researchers alike, has become readily treatable with surgical intervention at a very high rate of successful repair. The current study presents a retrospective case series exploring surgical outcomes for treatment of recurrent macular holes. The study additionally provides a window into the past, present, and future of macular holes across all clinical considerations, and importantly performs a supplementary statistical meta analysis of reoperation success rates in the relevant field of published data- the first of its kind. The introductory background of the present study establishes a natural history of idiopathic macular holes in clinical discovery, classification, and management. The study's case series data specifically focuses on the phenomenon of macular hole recurrence, offering surgical outcome measures of patients undergoing primary and secondary repair operations in a single-center, single-surgeon design. The findings of the retrospective series support the hypothesis that macular hole reoperation does achieve successful anatomical closure in a majority of cases. A meta analysis performed on the current field of published clinical research pertaining to recurrent macular holes established cumulative success rates across a variety of surgical conditions. The present study's findings were then compared to the corresponding measures across the landscape of recurrent macular hole literature, to help inform a niche of clinical research that continues to be an area of investigation and discovery. In presenting a cohesive, synthesized narrative of recurrent macular holes, the study provides a foundation wherein ongoing collaborative efforts in the field can continue to build upon a blueprint currently set in place, and work towards finding a cause behind an otherwise idiopathic disease.
12

Multiple Laser Photocoagulation Treatments for the Management of Diabetic Macular Edema

Vora, Sadhna Raju 15 November 2006 (has links)
The purpose of this study was to evaluate functional and funduscopic outcomes amongst patients receiving multiple treatments with macular laser photocoagulation for clinically significant diabetic macular edema. A record review was conducted of patients who had multiple macular laser treatments for diabetic macular edema. As part of routine follow-up for diabetic macular edema, visual acuity and funduscopic findings were assessed before a given laser treatment and at 6 months afterwards. The study included 64 eyes from 41 patients. There was no statistically significant difference between the proportion of eyes that showed funduscopic improvement after treatment 1 versus the proportion of eyes that improved after subsequent treatments. For the first laser treatment, 44 of the 64 eyes (69%) showed funduscopic improvement in edema. 35/64 (55%) of eyes showed improvement after the second treatment (p=0.15); 29/40 (72.5%) eyes showed improvement after the third treatment (p=0.85); 15/18 (83.3%) eyes showed improvement after treatments[greater than or equal to]4 (p=0.36). Similarly, in terms of visual acuity outcomes, there was no statistically significant difference between the proportion of eyes with preserved visual acuities after treatment 1 compared to repeat treatments. This study found that the majority of eyes that receive re-treatment after initial laser therapy will respond with an improvement in macular edema.
13

Avaliação da concentração sérica da lectina ligante de manose na degeneração macular relacionada a idade

Pradella, Fernando Morandini January 2014 (has links)
Orientadora : Profª. Drª. Iara José de Messias-Reason / Co-orientadores : Prof. Dr. Renato Mitsunori Nisihara e Prof. Dr. Mario Teruo Sato / Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências da Saúde, Programa de Pós-Graduação em Medicina Interna. Defesa : Curitiba, 27/08/2014 / Inclui referências : f. 58-64 / Resumo: Introdução: A Degeneração Macular Relacionada a Idade (DMRI) é a principal causa de cegueira no ocidente em pessoas acima de 65 anos de idade. Nos EUA, estima-se que mais de 8 milhões de pacientes tenham DMRI. A idade é o principal fator de risco e com o aumento da expectativa de vida, espera-se maior número de casos nos próximos anos. A atividade inflamatória na fisiopatologia da DMRI tem sido cada vez mais estudada e cresce em importância a cada dia, com vários mecanismos propostos, com especial atenção ao sistema complemento. Objetivos: Avaliação do papel da lectina ligante de manose (MBL) do sistema complemento em pacientes com DMRI. Pacientes e Métodos: Foram avaliados 136 indivíduos (60 homens e 76 mulheres), com idade acima de 55 anos. Dentre eles, 68 eram portadores de DMRI e 68 eram controles. Esses foram pareados com os pacientes de acordo com idade, sexo, características étnicas, socioeconômicas e origem geográfica. A concentração sérica de MBL foi avaliada através do método TRIFMA. O estudo foi realizado no Centro da Visão do Hospital de Clínicas da Universidade Federal do Paraná e compreendeu: consulta oftalmológica completa (exame oftalmológico, tomografia de coerência óptica com protocolo específico); coleta de sangue, análise laboratorial e estatística. Resultados: As concentrações de MBL não mostraram diferenças significantes quanto a etnia, idade, sexo, IMC ou tabagismo entre grupos de pacientes e controles. A mediana da MBL para os casos foi de 608 ng/mL (30 - 3415ng/mL) e controles 739 ng/mL (30 - 6039 ng/mL); p = 0,4770. Comparando-se DMRI exsudativa com a forma seca, observou-se menor concentração de MBL na forma exsudativa (476 ng/mL) em relação a forma seca (893 ng/mL). Entretanto, esses resultados não mostraram diferença estatisticamente significante (p = 0,1011). Houve discreta diminuição, não significativa, dos níveis de MBL com o avanço da idade nos controles. Conclusões: Os resultados obtidos não demonstraram associação entre a concentração sérica de MBL e a DMRI ou com suas formas clinicas exsudativa e seca. Palavras-chave: Degeneração macular relacionada a idade. Sistema complemento. MBL. Marcadores inflamatórios. / Abstract: Introduction: Age Macular Degeneration (AMD) is the leading cause of blindness in the Western population over 65 years. In the U.S., more than 8 million patients have some degree of AMD. The major risk factor for AMD is the age and due to the increase in the global life expectancy, a higher number of cases are expected. The inflammatory activity in the pathophysiology of the disease has been studied for years, gaining importance in the recent years. Several mechanisms have been proposed with special attention paid to the complement system. Objectives: To evaluate the role of mannose-binding lectin (MBL) of complement system in AMD patients. Patients and Methods: A total of 136 subjects with age over 55 years were evaluated (68 patients with AMD and 68 controls). All subjects were followed up at the Vision Centre of the Hospital de Clínicas - Federal University of Paraná in Curitiba - Brazil. For all individuals complete ophthalmologic exams and optical coherence tomography using a specific protocol were performed. Blood samples were collected for MBL measurement. Results: There was no difference regarding ethnicity, age, gender, BMI or smoking habits between patients and controls. The median MBL levels for AMD patients was 608 ng /mL (30-3415 ng/mL -) and for the controls 739 ng/mL (30-6039 ng/mL), with no statistically significant difference (p= 0,4770). There was no difference either when comparing exudative with dry AMD, with median MBL of 476 ng/mL in the exudative form and 893 ng/mL in the dry form (p=0,1011). There was no difference between men and women regarding MBL serum levels and a not significant decrease in MBL levels was observed with aging in controls. Conclusions: There was no association between MBL serum levels and AMD or with the exudative and dry clinical forms of AMD. Keywords: Age macular degeneration, complement system, MBL, inflammatory markers.
14

Effects of combination therapies on age-related macular degeneration

Lo, David January 2013 (has links)
Age-related macular degeneration (AMD) is the most common cause of vision loss in America for people over the age of 60. Due to damage to the retina, symptoms normally include blurred central vision, difficulty reading, and seeing shadows. While there is no cure for the disease, there are treatments that slow its progression and can restore vision. The treatments explored in this paper are: anti-vascular endothelial growth factor (VEGF) drugs, photodynamic therapy (PDT) and steroids. All three require invasive eye procedures that carry their own risks. The possibility of more effective treatments by combining these therapies is being tested through clinical trials. Studies of combined PDT and anti-VEGF, combined PDT and steroids, and anti-VEGF monotherapy were reviewed, comparing changes in average visual acuity, foveal thickness, and number of injections administered. PDT and anti-VEGF was concluded to be the most efficient of the three, requiring fewer injections while showing an increase in visual acuity similar to anti-VEGF monotherapy.
15

Bruch's membrane and its collagen

Karwatowski, Wojciech Stefan Stanislaw January 1997 (has links)
No description available.
16

Retinal Blood Flow and Vascular Reactivity in Diabetic Retinopathy

Gilmore, Edward 13 December 2006 (has links)
Introduction Retinal vascular reactivity is impaired in patients with diabetes and is thought to be involved in the onset and progression of diabetic retinopathy (DR). Previous studies that have utilized hyperoxia to assess retinal vascular reactivity have been limited due to confounding factors associated with the administration of oxygen and have used a variety of different instruments to measure retinal blood flow. The influence of blood glucose at the time of blood flow assessment has also not been systemically investigated. The specific aims of each Chapter are as follows: Chapter 3: To compare three systems used to administer hyperoxia to human subjects. Chapter 4: To quantify the magnitude and timeline of change of retinal hemodynamic parameters induced by an isocapnic hyperoxic stimulus. Chapters 5, 6 and 7: To quantify the magnitude of change of retinal hemodynamic parameters induced by hyperoxia, hyperglycemia and combined hyperoxia / hyperglycemia, respectively, in groups of diabetic patients with no clinically visible, and mild-to-moderate, DR and in age-matched subjects without diabetes. Methods Chapter 3: Subjects breathed air followed by oxygen, or oxygen plus carbon dioxide using a non-rebreathing system, or air followed by oxygen using a sequential rebreathing system. The magnitude of change and variability of CO2 concentrations was compared between systems. Chapter 4: Baseline retinal blood flow data was acquired while the subjects breathed air using a sequential rebreathing system. An isocapnic hyperoxic stimulus was initiated and maintained for 20 minutes. Air was then re-administered for 10 minutes. Retinal blood flow measurements were acquired every minute over the course of the study. The magnitude of change of each hemodynamic parameter was determined by fitting individual data with a sigmoidal function. For Chapter 5, 6 and 7 diabetic patients with no clinically visible, and mild-to-moderate, DR were stratified into groups based upon their retinopathy status. Age-matched non-diabetic subjects were recruited as controls. Baseline retinal blood flow data was acquired while subjects breathed air. Retinal blood flow measurements were then acquired after exposure to (a) hyperoxia, (b) hyperglycemia and (c) combined hyperoxic / hyperglycemic stimuli. Change in hemodynamic parameters was compared between groups and correlated with objective measures of retinal edema. Results Chapter 3: The difference in group mean end-tidal CO2 levels between baseline and hyperoxia was significant for oxygen administration using a non-rebreathing system. The sequential rebreathing technique resulted in a significantly lower variability of individual CO2 levels than either of the other techniques. Chapter 4: An ~11% decrease of diameter, ~36% decrease of velocity and ~48% decrease of blood flow was observed in response to isocapnic hyperoxia in young, healthy subjects. A response time of 2.30??0.53 minutes and 2.62??0.54 minutes was observed for diameter and velocity, respectively. Chapter 5: Retinal blood velocity, flow, and WSR significantly decreased in response to isocapnic hyperoxia in all groups. The magnitude of the reduction of blood flow was significantly reduced with increasing severity of retinopathy. There was a significant relationship between baseline objective edema index values and retinal vascular reactivity. Chapter 6: A significant change in blood glucose level was observed for all groups. No significant change in any hemodynamic parameter was found in patients with diabetes and in age-matched subjects without diabetes. Chapter 7: Retinal blood velocity and flow significantly decreased in all groups in response to combined hyperoxic / hyperglycemic provocation. The vascular reactivity response was not significantly different across the groups. Conclusions Chapter 3: Control of CO2 is necessary to attain standardized, reproducible hyperoxic stimuli for the assessment of retinal vascular reactivity. Chapter 4: Arteriolar retinal vascular reactivity to isocapnic hyperoxic provocation occurs within a maximum of 4 minutes. Although there was a trend for diameter to respond before velocity, the response characteristics were not significantly different between diameter and velocity. Different response characteristics of the retinal vasculature to transmural pressure mediated autoregulation as opposed to metabolic mediated vascular reactivity are suggested. Chapter 5: The vascular reactivity response in terms of the reduction of blood flow relative to baseline was significant in all groups but the magnitude of the change in flow was significantly reduced with increasing severity of retinopathy. A loss of retinal vascular reactivity is indicated in patients with moderate DR without clinically evident diabetic macular edema (DME), and in patients with DME. Chapter 6: Unaltered retinal arteriolar blood flow was found 1 hour after glucose ingestion in patients with diabetes and in age-matched subjects without diabetes. These results do not support the theory that retinal blood flow is affected by an acute increase of blood glucose in diabetic patients and in subjects without diabetes. Chapter 7: The vascular reactivity response to a combined hyperoxic / hyperglycemic provocation produced a pronounced reduction in blood flow. Unlike the response to hyperoxia alone, the vascular reactivity response was not significantly different across the groups. This suggests that hyperglycemia may influence the retinal vascular reactivity response to hyperoxia.
17

P2Y1 receptor signaling contributes to high salt-induced priming of the NLRP3 inflammasome in retinal pigment epithelial cells

Prager, Philipp, Hollborn, Margrit, Steffen, Anja, Wiedemann, Peter, Kohen, Leon, Bringmann, Andreas 14 December 2016 (has links) (PDF)
Background: Systemic hypertension is a risk factor of age-related macular degeneration (AMD), a chronic inflammatory disease. Acute hypertension is caused by increased extracellular osmolarity after intake of dietary salt (NaCl). We determined in cultured human retinal pigment epithelial (RPE) cells whether high extracellular NaCl alters the gene expression of inflammasome-associated proteins, and whether autocrine/paracrine purinergic (P2) receptor signaling contributes to the NaCl-induced NLRP3 gene expression. Methodology/Principal Findings: Hyperosmolarity was induced by the addition of 100 mM NaCl or sucrose to the culture medium. Gene and protein expression levels were determined with real-time RT-PCR and Western blot analysis, respectively. IL-1β and IL-18 levels were evaluated with ELISA. Nuclear factor of activated T cell 5 (NFAT5) expression was knocked down with siRNA. High extracellular NaCl induced NLRP3 and pro-IL-1β gene expression, while the gene expression of further inflammasome-associated proteins (NLRP1, NLRP2, NLRP6, NLRP7, NLRP12, NLRC4, AIM2, ASC, procaspase-1, pro-IL-18) was not altered or below the detection threshold. The NaCl-induced NLRP3 gene expression was partially dependent on the activities of phospholipase C, IP3 receptors, protein kinase C, the serum and glucocorticoid-regulated kinase, p38 MAPK, ERK1/2, JNK, PI3K, and the transcription factors HIF-1 and NFAT5. Pannexin-dependent ATP release and P2Y1 receptor activation is required for the full induction of NLRP3 gene expression. High NaCl induced a transient increase of the NLRP3 protein level and a moderate NLRP3 inflammasome activation, as indicated by the transient increase of the cytosolic level of mature IL-1β. High NaCl also induced secretion of IL-18. High extracellular NaCl induces priming of the NLRP3 inflammasome in RPE cells, in part via P2Y1 receptor signaling. The inflammasome priming effect of NaCl suggests that high intake of dietary salt may promote local retinal inflammation implicated in the development of AMD.
18

Veränderung der postoperativen zentralen Makuladicke nach Kataraktoperation unter Prostaglandinanaloga-Therapie im Vergleich zu einer Kontrollgruppe / Change in postoperative central macular thickness after cataract surgery with prostaglandin analog therapy compared to a control group

Guggenmoos-Schreyer, Felix Rudolph 13 August 2019 (has links)
No description available.
19

Effects of normobaric hyperoxia on diabetic macular edema and visual acuity

Zeng, Ke 17 June 2019 (has links)
PURPOSE: Diabetic macular edema (DME) is the most common cause of vision loss in patients with diabetic retinopathy. This study aims to approach diabetic macular edema and diabetic retinopathy as ischemic conditions and explores a potential treatment through hyperoxia. The study measured changes in retinal thickness, visual acuity, and contrast sensitivity in subjects receiving normobaric oxygen. METHODS: Fifty-one patients with diabetic macular edema at Beth Israel Deaconess Medical Center Eye Clinic (Boston, MA) received oxygen via a face mask at 5 liters per minute for 3 hours. Retinal thickness at the central subfield and maximal retinal thickness were measured using optical coherence tomography. Contrast sensitivity, best corrected visual acuity, and intraocular pressure were measured before and after oxygen as well. RESULTS: Macular thickness from diabetic macular edema decreased by an average of 2.09% (p < .05) at the point of maximal thickness, and by 0.88% (p < .05) at the central subfield. Vision also improved by an average of 0.043 LogMAR units (p < .05). Changes in macular thickness and visual acuity were non-significant in healthy control eyes that received oxygen. The results of hyperoxia on contrast sensitivity were indeterminate. CONCLUSIONS: We found that normobaric hyperoxia for 3 hours reduces macular thickness from diabetic macular edema and improves visual acuity. This study offers additional evidence that diabetic macular edema is an ischemic disorder and suggests that oxygen therapy may serve as an alternate or complimentary treatment of DME. / 2020-06-17T00:00:00Z
20

Catechins against sodium iodate-induced retinal degeneration. / CUHK electronic theses & dissertations collection

January 2013 (has links)
Yang, Yaping. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 156-165). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese.

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