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An adequate oxygenation and retinal perfusion is essential for the function of the inner retina. There is a wide range of autoregulation mechanisms to ensure a sufficient ocular blood and oxygen supply during changes in systemic blood pressure or intraocular pressure (IOP). Nonetheless, various retinopathies such as diabetic retinopathy, which is the leading cause of blindness in people aged 20-65 in the western world, are highly associated with hypoxia (Pemp and Schmetterer 2008). Hence, measurements of oxygen levels in retinal vessels are needed to further our understanding of these ischemic diseases. It is a well known fact and a commonly employed method to measure oxygen saturation of blood through light transmission (Kramer 1934). However, this approach is not feasible in the human eye. Therefore, reflection must be used, meaning the amount of incident light must be estimated based on the amount of light reflected (for a review see Harris 2003). This is a difficult task and investigators in this field have encountered several problems, including optical complexities, nonlinear sensors and eye movement (Beach et al 1999; Delori 1988). Nonetheless considerable progress has been made over the past decades and the development of an reliable oximeter reported (Hardarson et al 2006).
In the present study this technique will be applied in healthy subjects as well as in patients with COPD during room-air conditions. The procedure takes approximately 15 minutes in each subject and will be performed in only one eye.
Observational Model: Cohort, Time Perspective: Prospective
Department of Clinical Pharmacology, Medical University of Vienna
Not yet recruiting
Medical University of Vienna
Published on BioPortfolio: 2014-08-27T03:18:33-0400
Central retinal artery occlusions (CRAO) are the equivalent of an ischemic stroke (IS) at the retinal level. They share the same risk factors and common pathology. Their incidence is lower...
Purpose of the study is to examine the retinal blood flow in chronic cases of retinal artery occlusion with non-invasive, non-contact optical coherence tomography angiography.
Retinal artery occlusions (RAO) cause deterioration in visual acuity and visual fields. In computational fluid dynamics (CFD) studies [Kaufmann et al. 2012] 10% of ascending emboli caused ...
Retinal detachments correspond to a separation of the neuroepithelium from the pigment epithelium. They can be exudative (sometimes in conjunction with a tumor), tractional, traumatic (pos...
Remote ischemic conditioning (RIC) is a therapeutic strategy for protecting organs or tissue against the detrimental effects of acute ischemia-reperfusion injury. It remains unknown whethe...
We report a patient with branch retinal artery occlusion predominant Susac syndrome and review the literature on current diagnostic modalities and therapeutic approaches for this rare condition.
Here we report the case of a 78-year-old male patient with a 2-day history of low visual acuity and fundus and who was diagnosed with central retinal artery occlusion. In addition, the patient had an ...
To report on the rate and timing of retinal reattachment and outcomes for retinoblastoma children who have total retinal detachments at presentation to our center and were treated with intra-arterial ...
The aim was to quantitatively compare retinal vascular detail as seen on optical coherence tomography angiography (OCTA) and matched histology in the human eye. 13 normal human donor eyes were used. T...
This case report presents a patient with central retinal artery occlusion (CRAO) who was successfully treated with hyperbaric oxygen (HBO₂) but subsequently suffered a recurrence of his visual loss.
Central retinal artery and its branches. It arises from the ophthalmic artery, pierces the optic nerve and runs through its center, enters the eye through the porus opticus and branches to supply the retina.
Sudden ISCHEMIA in the RETINA due to blocked blood flow through the CENTRAL RETINAL ARTERY or its branches leading to sudden complete or partial loss of vision, respectively, in the eye.
Transient complete or partial monocular blindness due to retinal ischemia. This may be caused by emboli from the CAROTID ARTERY (usually in association with CAROTID STENOSIS) and other locations that enter the central RETINAL ARTERY. (From Adams et al., Principles of Neurology, 6th ed, p245)
Direct myocardial revascularization in which the internal mammary artery is anastomosed to the right coronary artery, circumflex artery, or anterior descending coronary artery. The internal mammary artery is the most frequent choice, especially for a single graft, for coronary artery bypass surgery.
A group of rare, idiopathic, congenital retinal vascular anomalies affecting the retinal capillaries. It is characterized by dilation and tortuosity of retinal vessels and formation of multiple aneurysms, with different degrees of leakage and exudates emanating from the blood vessels.
Diabetes is a lifelong condition that causes a person's blood sugar level to become too high. The two main types of diabetes are: type 1 diabetes type 2 diabetes In the UK, diabetes affects approximately 2.9 million people. There are a...
Within medicine, nutrition (the study of food and the effect of its components on the body) has many different roles. Appropriate nutrition can help prevent certain diseases, or treat others. In critically ill patients, artificial feeding by tubes need t...