View clinical trials related to Diabetic Retinopathy.
Filter by: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 compare the amount of intraoperative intraocular bleeding during 23-gauge pars plana vitrectomy (PPV) for diabetic traction retinal detachment (TRD) with and without preoperative intravitreal bevacizumab treatment.
Imaging of retinal morphological changes with time secondary to laser treatment as assessed with high definition optical coherence tomography (OCT). Furthermore changes in retinal function as an effect of treatment will be documented by visual acuity testing using ETDRS charts and microperimetry. The change in vascular leakage will be assessed by performing fluorescein angiography, flare counts will be performed monthly.
Evaluation of safety and tolerability of a single injection of NOVA63035 "Corticosteroid" administered at one of four doses in patients with diabetic macular edema (DME) secondary to diabetic retinopathy
Persistent or recurrent vitreous hemorrhage after vitrectomy for diabetic retinopathy complications is a common occurrence with an incidence of 12% to 63%. This complication may prolong vitreous clear-up and delay visual rehabilitation significantly, and sometimes requires additional procedures or surgery. The causes of bleeding are diverse. Evidence suggests fibrovascular proliferation from the sclerotomy sites or from the vitreous base may be an important source of recurrent vitreous hemorrhage; other sources of bleeding include iatrogenic intraoperative injury of retinal vessels, and incomplete removal of fibrovascular tissues. We have reported on the possible benefit of peripheral retinal cryotherapy and cryotherapy treatment of sclerotomy sites to prevent delayed-onset recurrent vitreous hemorrhage, and the possible benefit of intravitreal long-acting gas to reduce the occurrence of early postoperative recurrent vitreous hemorrhage, especially for cases with active fibrovascular proliferation. However, minor recurrent vitreous hemorrhage and prolonged reabsorption of lysed blood clots from surgical trauma remain important factors to cause media opacity long enough to prevent quick visual rehabilitation. Intravitreal bevacizumab has been noted to induce rapid regression of retinal and iris neovascularization in proliferative diabetic retinopathy. Further, presurgical administration of intravitreal bevacizumab may reduce intraoperative bleeding during membrane dissection in PDR with traction retinal detachment. We hypothesize that presurgical treatment of intravitreal bevacizumab may reduce intraoperative bleeding and the amount of residual blood clots, while intraoperative infusion of long-acting gas may facilitate post-operative recovery of surgically injured retinal vessels. These combined effects would thus enhance early clear-up of vitreous opacity from clot lysis and recurrent retinal bleeding. To investigate this hypothesis, a clinical prospective study was undertaken to evaluate the effects of bevacizumab pretreatment combined with intravitreal infusion of long-acting gas on the clearance speed and the recurrence rate of early postoperative vitreous hemorrhage in vitrectomy for active diabetic fibrovascular proliferation.
This study will identify genes that are associated with inflammation or degeneration of the retina (membrane lining the back of the eye that relays vision signals to the brain). It is thought that many retinal conditions are due to an altered immune system and are based on how the person s genes function and communicate. People 4 years of age or older who have a retinal condition such as uveitis, age-related macular degeneration or diabetic retinopathy may be eligible for this study. Healthy volunteers and healthy people who have a family member with one of these conditions are also eligible. Patients with inherited retinal degeneration are excluded. Participants undergo the following tests and procedures: - Eye examination to assess visual acuity (eye chart test) and eye pressure, and to examine the pupils, lenses, retina and eye movements. Photographs of the inside of the eye may also be taken. The pupils are dilated with drops for this examination. - Blood draw for genetic testing. Participants may also undergo one or more of the following tests: - Optical coherence tomography. This is a type of photograph of the back of the eye to measure thickness of the retina. - Fluorescein angiography and indocyanine green angiography. Pictures of the eye s blood vessels are taken using either a fluorescein or indocyanine green dye. The dye is injected into a vein in an arm and travels to the blood vessels in the eyes. A camera takes pictures of the dye as it flows through the blood vessels. - Electroretinogram (ERG) to measure retinal function. The patient sits in a dark room for 30 minutes with his or her eyes patched. Then, a small metal disk electrode is taped to the forehead, the eye patches are removed, the surface of the eye is numbed with eye drops, and contact lenses are placed on the eyes. The patient then watches flashing lights. The contact lenses sense small electrical signals generated by the retina when the light flashes....
The purpose of this study is to determine if diabetic retinopathy can be treated with prostaglandin analogues, prostaglandin synthesis inhibitors or carbonic anhydrases inhibitors.
Diabetic neovascularization refers to a type of diabetic retinopathy which is worsening by the abnormal growth of blood vessels in the back of the eye, damaging the retina. The usual treatment is a type of laser, called panretinal photocoagulation. One drawback is that the amount of space within the eye for use of this treatment eventually has its limit, and should not be used too near the part of the retina used for detailed vision (the macula). In similar eye disorders, there are certain injectable medications called anti-VEGF treatments which can slow down or stop this abnormal blood vessel growth. This study sought to compare use of ranibizumab versus standard panretinal photocoagulation in treatment of diabetic neovascularization.