View clinical trials related to Diabetic Retinopathy.
Filter by:Macular hole in proliferative diabetic retinopathy with fibrovascular proliferation may have unique features. Internal limiting membrane peeling facilitates hole closure only in cases with shallow macular detachment. Final vision is associated with preoperative visual acuity and degree of macula elevation.
Vitrectomy is one of the major treatment methods for complications of diabetic retinopathy. As surgical techniques and instruments improve, high anatomical success may be achieved; however, functional results are less favorable. Despite attached retina, postoperative visual function may be affected by various macular and disc abnormalities. Major changes include optic atrophy, atrophic retina, poor macular perfusion, and structural alternations of the macula. Funduscopy, fluorescein angiography, and, more recently, optical coherence tomography (OCT) can be used to detect and document these alterations. Although fluorescein angiography is valuable in the assessment of various macular lesions as well as retinal vascular abnormalities, its usefulness in evaluating macular changes is limited in eyes that have undergone diabetic vitrectomy. The quality of the images may be compromised by mild diffuse hyperfluorescence in the posterior pole in middle and late phase angiography, which obscures capillary detail and subtle macular changes. Furthermore, quantification of changes may not be possible. Recently, optical coherence tomography has become very useful for the detection of vitreomacular abnormalities. The examination is noninvasive, can qualify the changes and detect subtle abnormalities not evident with other imaging studies. In this study, OCT was applied to investigate how common macular structure abnormalities are present after surgery for complications of diabetic retinopathy, and how they may affect visual prognosis.
Fractalkine (FKN) is a chemoattractant and adhesion molecule for leukocytes. Angiogenic effect of FKN also has been reported. We investigate FKN-mediated angiogenesis in ocular angiogenic disorders.
To more clearly ascertain the relationship between ocular manifestations of sickle cell disease and diabetes, specifically; whether the presence of sickle cell trait exacerbates the disease progression of diabetic retinopathy.
There is evidence from a variety of animal studies that choroidal blood flow is under neural control. Recent results in humans indicate that a light/dark transition is associated with a short lasting reduction in choroidal blood flow. Several observations indicate that the changes in choroidal perfusion are triggered at least in part by neural mechanisms. Particularly, we have shown that during unilateral dark/light transition both eyes react with choroidal vasoconstriction strongly indicating a neural mechanism for blood flow regulation. Investigation of changes in choroidal blood flow during light/dark transition may represent an interesting approach to study neural dysregulation at the level of the eye in patients with IDDM. Accordingly, the hypothesis of reduced choroidal blood flow responses to a light/dark transition in patient with IDDM will be tested. This response in choroidal blood flow will be correlated to parameters of diabetic neuropathy and diabetic retinopathy.
A variety of studies demonstrate that ocular blood flow is altered in diabetes and retinal perfusion abnormalities have been proposed to contribute to the pathogenesis of diabetic retinopathy. Various animal and human studies have demonstrated that retinal and optic nerve blood flow increase in response to diffuse luminance flicker. Based on studies with ERG, this effect has been attributed to augmented activity in the retinal ganglion cells and associated axons indicating a coupling mechanism between neuronal activity and retinal blood flow. Whereas a variety of studies describe the effects of flickering light on retinal and optic nerve head blood flow, the knowledge about this coupling in the diabetic retina is sparse. In view of the fact that neural activity and blood flow are strongly coupled in the human retina, one could hypothesize that neurodegenerative changes in the retina could contribute to the vascular dysregulation and in turn lead to changes of ocular perfusion. The investigators set out to investigate whether the coupling of neural activity and blood flow is impaired in patients with early stage diabetic retinopathy compared to those in healthy volunteers.
Objective: Diabetic macular edema (DME) is a frequent manifestation of diabetic retinopathy, a leading cause of blindness in the United States. The only proven treatment for DME is laser photocoagulation. Sirolimus has been shown to inhibit the production, signaling and activity of many growth factors relevant to the development of diabetic retinopathy. Therefore, this study will investigate the safety and efficacy of multiple sirolimus injections in patients with DME. Study Population: Eligibility criteria include central macular thickening > 260 microns and visual acuity 20/32 or worse in one or both eyes. Design: Five participants will be enrolled into this open-label pilot study. After receiving a 20 μL (440 μg) subconjunctival injection in the study eye at baseline and Month 2, the participants will be re-evaluated every two months for at least one year for possible additional injections. During follow-up, participants will not undergo re-injection if they show significant clinical improvement or treatment success, defined as no intraretinal fluid or cysts present on optical coherence tomography (OCT) OR 100% reduction in excess retinal thickness over 260 microns on OCT OR no leakage on fluorescein angiography (FA). Beginning at Month 4, participants will be assessed for treatment failure, defined as loss of 15 or more letters of vision compared to baseline at two consecutive visits OR a 50% or greater increase in total retinal thickness as measured by OCT at two consecutive visits. Individual participants deemed treatment failures will continue receiving sirolimus injections, but will be allowed to receive focal laser therapy for any amenable leaking microaneurysms at Month 4. Beginning at Month 6, focal laser therapy will be permitted for both treatment failures and participants who do not meet the criteria of a treatment success. Participants will have the option of continuing treatment until a common termination date of one year. Outcome Measures: The primary outcome is the change in visual acuity in the study eye at six months compared to baseline. Secondary outcomes include changes in visual acuity in the study eye at one year as compared with baseline, changes in retinal thickness as measured by OCT and changes in fluid leakage in the macula as demonstrated by FA at six months, one year and throughout the study period in the study and fellow eyes. Safety outcomes include number and severity of systemic and ocular toxicities, adverse events and infections, and the number of participants withdrawn from study therapy.
The study is designed as a prospective cohort study to assess changes in visual acuity and retinal thickening and surgical complications in subjects undergoing vitrectomy for diabetic macular edema. The study also aims to identify subgroups in which there appears to be a benefit of vitrectomy and subgroups in which vitrectomy does not appear to be beneficial and to obtain data that can be used to plan a randomized trial. Subject will be followed through 2 years, with a primary outcome at 6 months post vitrectomy surgery. The vitrectomy procedure will be performed based on the investigators usual care and is not considered part of the research although the procedure performed will be collected.
The purpose of this study is to determine whether systemic administration of darbepoetin alpha results in the progression or regression of diabetic macular edema.
Diabetic macular edema is a common cause of visual loss among diabetic patients. Studies have demonstrated the role of vascular endothelial growth factor (VEGF) in the pathogenesis of edema. This study designed to evaluate the effect of Intravitreal injection of a recombinant monoclonal anti-VEGF antibody, Bevacizumab, for treatment of diabetic macular edema.