View clinical trials related to Optic Disk.
Filter by:The presence of optic disc swelling at the fundus is a non-specific clinical sign that can occur in many ophthalmologic, neuro-ophthalmologic or encephalic pathologies. The diagnostic range is vast, including inflammatory pathologies of the optic nerve, infiltrative or compressive orbital pathologies, idiopathic or secondary intracranial hypertensions, not to mention the pseudo optic disc swelling found in drüsens. MRI is increasingly being used as a first-line examination to obtain an etiologic diagnosis in a patient with optic disc swelling. It allows a rapid diagnosis to be made in cases of inflammatory pathology or compressive or infiltrative pathology. It can provide very suggestive elements in the case of intracranial hypertension. It appears to be potentially useful in diagnosing ischemic optic neuropathy or in directing towards an etiological diagnosis of Giant Cell Arteritis. The development of new high-resolution MRI sequences has made it possible to obtain extremely fine resolutions of a few hundred microns in the plane. Apart from a few clinical cases and small series, there is no precise evaluation of the interest of these new sequences in the positive and etiological diagnosis of ophthalmological, neuro-ophthalmological and encephalic pathologies responsible for the presence of optic disc swelling. The objective of our study is therefore to evaluate the diagnostic contribution and the gain in diagnostic confidence provided by these new sequences in the context of pathologies manifesting as optic disc swelling.
Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. The existence of an effective autoregulation in the optic nerve circulation has been shown in animals and humans. The exact mechanism behind this autoregulation is still unknown. The motive for the investigation of optic nerve head (ONH) blood flow autoregulation is to enhance the understanding of pathologic eye conditions associated with ocular vascular disorders. To clarify the regulatory mechanisms of ONH microcirculation is of critical importance to understand the pathophysiology of glaucoma because there is evidence that glaucoma is associated with optic nerve head ischemia. Several studies indicate that a disturbed autoregulation might contribute to glaucomatous optic neuropathy. Previous findings suggest endothelial dysfunction in glaucomatous optic neuropathy, in particular alterations in endothelin- and nitric oxide- system, which both play an important role in local regulation of vascular tone. In the present study, changes in ocular perfusion pressure will be performed during administration of drugs, which may potentially alter the pressure-flow relationship. These drugs include endothelin-1 and the nitric oxide synthase inhibitor NG-monomethyl-L-arginine (L-NMMA).
Because of their antiinflamatory effects, glucocorticoids are often used to reduce edema in neurologic tissue and to otherwise mitigate the consequences of neural inflammation. For example, high dose prednisolone treatment has been shown to be an effective therapy for different eye diseases including severe Graves´ Ophthalmopathy and acute optic neuritis. However, contradictory results exists for the influence of high dose prednisolone therapy per se on tissue blood flow. Thus, in the current study, we plan to investigate the effect of high dose, short time therapy with intravenous prednisolone in patients with optic neuritis and severe Graves´ Ophthalmopathy.