View clinical trials related to Normal Tension Glaucoma.
Filter by:In addition to intraocular pressure blood perfusion pressure in the optic nerve is an important factor determing the cause of glaucoma. Increasing evidence suggests that in glaucoma patients retinal blood may be decreased.
Glaucoma is characterized by a progressive loss of retinal ganglion cells (RGCs) leading to optic nerve head (ONH) damage and associated visual field defects. The main risk factor for glaucoma is elevated intraocular pressure (IOP). Reducing IOP slows down the progression of the disease as several large multicenter trials have shown. Some patients, however, still progress despite adequately controlled IOP. As such, there is considerable interest in approaches that rescue RGCs independent of IOP, a strategy called neuroprotection. Although this field was actively discovered in the last 20 years in the brain and the eye, no non-IOP related treatment is clinically available to date. Various approaches are currently studied in some detail. One interesting strategy focuses on the neurovascular unit. The blood flow of the human retina is controlled by complex mechanisms that include myogenic, metabolic and hormonal factors. The high consumption of oxygen in the human retina is crucial for normal functioning of the organ. As in the brain, blood flow in the retina is also controlled by neurovascular coupling. This means that the retina increases its blood flow to regions in which neurons are activated. This is done in an effort to provide more oxygen and glucose to the active neurons. In the recent years evidence has accumulated that astrocytes play a key role in mediating this vasodilator signal. In the brain, abnormalities in neurovascular coupling have been observed in diseases like stroke, hypertension, spinal-cord injury and Alzheimer's disease. This break-down of neurovascular coupling is considered to play a key role in neuronal death in these diseases. In the retina, abnormalities in neurovascular coupling have been observed in diseases as diabetes and glaucoma. Most of the data obtained in the human retina stem from a system that measures retinal vasodilatation during stimulation with flickering light. The investigators have previously shown that flicker stimulation of the retina is, however, also associated with a pronounced increase in retinal blood velocities. In this study the investigators employed laser Doppler velocimetry (LDV) for the measurement of retinal blood velocities, but this technique is not clinically applicable because it requires excellent fixation of the subject under study. In the present study, the investigators propose to use an alternative system for neurovascular coupling that they have developed recently. In this approach, the investigators use bi-directional Fourier-domain optical coherence tomography for the assessment of retinal blood flow. Optical coherence tomography (OCT) is a non-invasive optical imaging modality enabling cross-sectional tomographic in vivo visualization of internal microstructure in biological systems. In ophthalmology, OCT has become a standard tool in visualizing the retina and nowadays is considered also as a standard tool in the diagnosis of retinal disease. In the recent years, conventional time domain OCT was replaced by Fourier domain OCT providing significantly improved signal quality. This bidirectional system overcomes the limitations of previously realized techniques, which include doubtful validity and limited reproducibility. In addition, pattern ERG, multifocal ERG and oscillatory potentials will be measured to allow for concomitant assessment of neural function. The investigators seek to measure neurovascular coupling in the human retina in patients with early primary open angle glaucoma (POAG), normal tension glaucoma, ocular hypertension and a healthy control group. In order to obtain information on neurovascular coupling, both neuronal function as well as retinal blood flow need to be measured. In the present study, the investigators will employ pattern ERG, multifocal ERG as well as oscillatory potentials to assess the function of the inner retina. Retinal blood flow through major retinal arterial and venous branch vessels will be measured before, during and after flicker stimulation with the dual-beam bidirectional Fourier Domain Doppler OCT coupled to the commercially available Dynamic Vessel Analyzer (DVA) produced by IMEDOS, Jena, Germany, which provides adequate resolution to study the retinal circulation.
The purpose of this study is to evaluate the effect of Ginkgo biloba extract (GBE) on the number of blood vessels in the back of the eye as well as the amount of blood flow at the nailfold(where the fingernail meets the skin) of the 4th finger in the hand.This finger, along with the 5th finger, has the most transparent skin, which makes imaging a little easier. GBE is an over-the-counter pill, made from a natural powder taken from the Gingko (Maidenhair) tree, that is widely used. A technique called Optical Coherence Tomography Angiography (OCTA),will be used to measure the small blood vessels at the back of the eye, the macula (the area of sharpest vision), and the optic disc (the point at which the nerve fibers from the retina enter to form the optic nerve, which transmits visual impulses to the brain).
Purpose: To analyze the relationship between normal-tension glaucoma (NTG) and serum bilirubin levels. Materials and Methods: This research included 38 patients with NTG and 38 healthy controls with similar age and sex distribution, for a total of 76 subjects. Serum samples were taken from all of the subjects, direct serum bilirubin, indirect serum bilirubin and the total serum bilirubin were measured.
This study evaluates the possible acute changes in peripapillary blood flow after instillation of antiglaucoma medications in patients with primary open angle glaucoma (POAG), normal tension glaucoma (NTG), or ocular hypertension (OHTN) using Optical Coherence Tomography (OCT) angiography.
Evaluation of the optimal dose for the efficacy in reduction of intraocular pressure and safety of PHP-201 ophthalmic solution in patients with normal tension glaucoma
The objective of this study is to evaluate the long-term efficacy and safety of COMBIGAN® (brimonidine tartrate/timolol malate) in patients only using COMBIGAN® (brimonidine tartrate/timolol malate) and also in patients who require additional IOP lowering with LUMIGAN® (bimatoprost) 0.01%.
Globally primary open angle glaucoma (POAG) affects over 60 million people. The exact pathogenesis of POAG is poorly understood. A significant risk factor for glaucoma is advancing age. The rate of ageing is not the same in all age matched individuals. The concept of accelerated ageing suggests that the presence of a number of specific genetic, environmental or systemic risk factors may cumulate to accelerate the ageing process in some individuals and lead to the development of age-related disease. Understanding the factors that influence accelerated ageing is vital. Advanced glycation end products (AGEs) are a complex group of compounds that are naturally formed. They accumulate gradually with age in cells, tissues and blood vessels throughout the body where they adversely affect structure and function. Circulating AGE levels can be influenced by oxidative stress levels and dietary intake. Recent research has found that sustained exposure to high levels of circulating AGEs could be a major factor in the development of a number of chronic age-related degenerative disorders, including POAG. To date there have been few clinical studies that have been able to non-invasively explore the association between AGE levels and the development and progression of glaucomatous optic neuropathy (GON), or to explore the possible contribution that oxidative stress and dietary intake make to total tissue AGE levels in such patients. Furthermore little is understood about the relationship between AGE levels and retinal vascular function, a parameter known to be altered in GON that also could be influenced by AGE levels. The proposed study will aim to evaluate whether tissue-bound AGE levels are associated with parameters of retinal vascular function, oxidative stress, dietary intake and the presence of GON. Establishing this association could increase our understanding of the pathogenesis of GON and allow a new biomarker for accelerated ocular ageing to be realised
The main aim of this study is to determine the trans-laminal cribrosa pressure difference (TLCPD) for normal tension glaucoma (NTG) patients from the brain and the eye in supine, upright and minor head down tilt positions. It is also to investigate the venous drainage system in the same body positions.
The purpose of this study is to investigate IOP reduction efficacy of travoprost 0.004% ophthalmic solution (TRAVATAN Z®) in subjects with normal tension glaucoma.