View clinical trials related to Retina.
Filter by:The purpose of this clinical trial is to evaluate the effect of different intensity of repeated low-level red-light (RLRL) therapy on the choroidal and retinal blood flow among adults.
The purpose of this clinical trial is to evaluate the effect of different intensities of repeated low-level red-light (RLRL) therapy on the choroidal and retinal blood flow among adults.
Alzheimer disease is hard, long and expensive to diagnose. In order to help the clinician, a new biomarker in Alzheimer disease seems to be very useful. The retina, as a window of the brain, could offer a new way to diagnose this common disease. Indeed, a retinal atrophy could especially appear in Alzheimer disease. Besides, many aspects about retinal alteration, visual function and their link with the disease deserve to be more explored. So as to fill these gaps, a new study about retinal specificity in Alzheimer disease appears to be relevant.
Mainstream oximetry devices use two-wavelength systems to photograph the retina and estimate the oxygen saturation levels in the retinal vessels by comparing light absorption in the blood of the vessels at the selected wavelengths. This method limits the measurements to large retinal vessels, depends heavily on calibration and is non-reproducible across machines. The few numbers of wavelengths used (two) also makes it very susceptible to noise (such as cataract). These shortcomings have largely limited the use of retinal oximetry in clinical practice. A new technology for retinal oximetry has recently been developed to address issues of dual-wavelength oximeters. Zilia Ocular's oximetry machine uses multi-wavelengths of light to take continuous oxygenation measurements of any targeted regions of the retina. It can measure any area of the retina, including the blood vessels, retinal tissues and the optic nerve head. Its multi-wavelength design also allows it to be less susceptible to noise, more precise and reproducible. This technology has the potential to extend our understanding of retinal pathologies, serve as a new marker for retinal health and even be used as a diagnostic tool to detect retinal injuries before they become visible. Zilia's novel technology is one of its kind, allowing continuous and accurate measurements of the retina's oxygen saturation. In order to apply this technology to study and investigate retinal diseases, we need to first examine its performance in normal eyes and build a normative database as a reference. Thus, the purpose of the current study is to build a database of baseline oximetry values in healthy Caucasian subjects. The reproducibility of the measurements will also be studied in a subset of patients.
Improvement of retinal medical imaging opens new perspectives for exploring the retinal structures. Optical coherence spectral domain (SD-OCT), which has been widely used in the last ten years, is certainly the most advanced device. In the analysis of patients without retinal disease using SD-OCT, granulations in the interdigitation area were observed. These granulations have never been described with this device. They could correspond either to the degradation products of the external segments of the photoreceptors or to melanosomes. A descriptive study of these granulations at different examination times and in different lighting situations would allow us to obtain essential information for a better understanding of this area. Based on the results, larger studies could explore this area more finely in retinal pathologies involving dysfunctions of photoreceptors or of the pigmentary epithelium.
This protocol is an extension of protocol 0002, Proof of Concept and Dose Ranging Study of carbidopa-levodopa in Neovascular AMD. that is a 3 month study of escalating doses of carbidopa-levodopa in neovascular AMD. This trial is a 9 month extension for patients who successfully complete protocol 0002 and wish to continue carbidopa-levodopa therapy. It will use the two higher dose regimens of protocol 0002. these will be assigned according to how well the higher dose was tolerated in protocol 0002.
An increasing number of clinical studies on SD-OCT of ocular pathologies and potential new clinical applications has recently been published in the peer-reviewed literature. However, the successful use of SD-OCT in routine clinical use depends upon the diagnostic sensitivity, biometric accuracy and reliability of the SD-OCT machines. This prospective, comparative, observational study aims to evaluate the imaging quality and diagnostic performance of two commercially available SD-OCT machines for both the anterior and posterior segment of the eye.
Retinal emboli is a common phenomenon in cardiac catheterization. In this study the investigators evaluate the incidence of retinal emboli post diagnostic and therapeutic cardiac catheterization over 300 patients. The incidence was 6.3% and had no clinical sequel on visual acuity and visual field.
Impaired retinal blood flow has been implicated in the pathogenesis of diabetic retinopathy. Patel et al. (1992) showed that retinal blood flow increases with the level of diabetic retinopathy. Grunwald et al. (1996) reported that patients with insulin dependent diabetes mellitus (IDDM) of relatively short duration have increased retinal blood flow, even before the onset of diabetic retinopathy. On the other hand the data of Bursell et al. (1996) indicate that IDDM patients have reduced retinal blood flow, when they have normal blood glucose levels, but this study may have considerable methodological limitations. Acute elevations of blood glucose levels, however, result in an increase in retinal blood flow (Grunwald et al. 1987, Bursell et al. 1996). Based on previous experimental data the investigators hypothesize that ocular blood flow is increased in early diabetes and reduced at later stages of the disease. Previous studies have demonstrated that metabolic conditions such as hyperglycemia influence outcome parameters and thereby might have confounded results regarding ocular blood flow in diabetic retinopathy. The investigators will therefore study patients with IDDM during euglycemic conditions.
A number of common eye diseases such as retinal artery and vein occlusion, diabetic retinopathy, age-related macular degeneration, glaucoma and anterior ischemic optic neuropathy are associated with ocular perfusion abnormalities. Although this is well recognized there is not much possibility to improve blood flow to the posterior pole of the eye in these diseases. Since many years, moxaverine is used in the therapy of perfusion abnormalities in the brain, the heart and the extremities. This is based on a direct vasodilator effect of the drug, but also on the rheological properties of red blood cells. Whether moxaverine affects blood flow in the eye is unknown. The present study aims to investigate whether moxaverine may improves blood flow in the eye after systemic administration.