View clinical trials related to Normal Tension Glaucoma.
Filter by:Purpose: To study the feasibility of a larger study by determining the tolerability of measuring blood pressure (BP) and intraocular pressure (IOP) over 24 hours in an ambulatory fashion with automatic devices. Participants: 20 patients with moderate to severe normal tension glaucoma and 20 non-glaucomatous patients. Procedures (methods): Both BP and IOP will be measured automatically in each participant in an ambulatory fashion during a 24-hour period. BP will be monitored using an appropriately sized cuff Oscar 2 (Suntech Medical, Morrisville, NC), which will be placed by a person trained in ambulatory BP monitoring devices. The device will be set up to automatically inflate every 30 minutes during the day and every hour during the night to measure and record the BP. IOP will be measured using Sensimed Triggerfish contact lens (Sensimed AG, Lausanne, Switzerland); the measurements will be taken and recorded every 10 minutes. The contact lens will be inserted by eye doctors (investigators). Both monitoring devices will be removed the following day.
Glaucoma is among the leading causes for blindness in the western world. Elevated intraocular pressure (IOP) has been identified as the most important risk factor. However, some patients progress despite adequate IOP lowering while some subjects with elevated IOP never develop glaucoma. Other patients develop glaucoma although IOP measurements were always in the normal range. Therefore, other factors must be involved. In the last years, studies using MRI have been performed and evidence has accumulated that also changes in retrobulbar structures are present, in particular in the lateral geniculate nucleus and the visual cortex. However, these studies were limited by the low spatial resolution of the MRI instruments used. The investigators propose to overcome this problem by using an ultrahigh-field Magnetom 7T whole-body MR scanner (Siemens Medical, Germany) installed at the MR Centre of Excellence at the Medical University of Vienna. This scanner is equipped with a 32-channel head coil and the SC72 high-performance gradient system and is thus perfectly suited for structural and functional imaging. The aim of the present study is to investigate whether structural and functional parameters are altered in patients with primary open angle glaucoma (POAG), normal tension glaucoma (NTG), ocular hypertension (OHT) compared to healthy control subjects. The exact topographical survey of intracranial structures such as the LGN and the assessment of neuronal structures by DTI may allow for the better assessment of therapeutic responses to new neuroprotective agents.
Clinical features, optical coherence tomography findings and surgical outcome in eyes with macular retinoschisis and detachment with normal tension glaucoma but without optic disc pit or high myopia were evaluated.
Glaucoma is a leading cause of blindness worldwide, whose treatment - intraocular pressure lowering - is only partially effective in preventing disease progression. Accordingly, other variables, such as ocular blood flow-related factors, have been implicated in disease pathogenesis. However, most findings involving vascular variables come from partial, small-scale studies. Furthermore, recent technological advances have identified a number of ocular blood flow variables that have yet to be tested in large scale trials. Therefore, a study that specifically aims at uncovering the role of vascular aspects in glaucoma is needed. For this purpose, a cross-sectional, observational case-control study will be conducted in the University Hospitals Leuven. This will be the largest-yet study on the subject, involving more than 750 patients. This will allow the creation of a specific cohort of patients where the vascular aspects are thought to be particularly important (low-tension glaucoma). It will use the largest combination yet of vascular-related measuring techniques (dynamic contour tonometry, optic coherent tomography, colour Doppler imaging and retinal oximetry)
Ocular blood flow has been consistently demonstrated to be altered in glaucoma patients when compared to otherwise healthy individuals. Numerous Doppler studies have shown a decrease in flow velocities in the retrobulbar arteries in what appears to be related to the degree of the glaucomatous disease. The anatomic pathway of the several arteries into the eye is intricately complicate, with at least one of them (the central retina artery) penetrating the optic nerve before entering the eye and supplying the innermost structures of the globe. As the optic nerve is surrounded by a layer of cerebrospinal fluid (CSF) which is in continuity with the rest of the central nervous system, this central retinal artery has also to cross this CSF containing compartment. Because of the intrinsic pressure this CSF - corresponding to the intracranial pressure at the orbital level - the possibility exists that this pressure around the optic disc could affect the blood flow of the arteries that go through it. The investigators will try to detect if a correlation exists between the optic nerve sheath diameter and the blood flow in the retrobulbar vessels of glaucoma patients.
A spontaneous venous pulsation over the optic disc is an ophthalmological sign that can potentially be found in up to 98% of healthy individuals. In fact, the lack of this spontaneous retinal venous pulse has been consistently implicated as an indicator of a more advanced form of certain ocular diseases, specifically open-angle glaucoma. However, the mechanisms behind these change in the retinal venous system are not clear. Some evidence suggests that extraocular features such as intracranial pressure (ICP) may play a role in regulating the intraocular venous outflow. The reasons for this hypothetical downstream resistance to venous outflow are not fully understood, with advances in this field being limited by our technological-imposed difficulties in assessing the structures behind the globe. However, it has been established that the volume of cerebrospinal fluid surrounding the optic nerve correlates with the ICP at the orbital level. Recent studies have suggested that non-invasive ultrasound-based recordings have correlated this surrogate for orbital ICP with the intraocular pressure (IOP) in glaucoma patients with an otherwise normal IOP range (normal tension glaucoma - NTG). The investigators will therefore conduct a test to determine if this cerebrospinal volume surrounding the optic nerve correlates with the frequency of observation of an otherwise signal of venous dysfunction (i.e. the lack of a visible pulse in the retinal central vein) Additionally, the investigators will assess if this correlation is different between healthy individuals, hypertensive primary-open angle glaucoma or NTG patients.
Retinal ischemia is thought to play an important role in the pathogenesis of glaucoma. Recent findings have confirmed that there is a direct correlation between the levels of venous oxygen saturation and the degree of the glaucomatous disease, presumably due to a decrease in retinal cell metabolism. However, glaucoma patients have been suggested to have a different pattern in retinal venous circulation. For instance, the observation of a visible pulsating central retinal vein is a phenomenon that can be seen in up to 98% of the healthy individuals but is identifiable in less than 50% of glaucoma patients. While the nature of these venous changes are not year clear, the lack of a visible pulsating flow could suggest an increased intraluminal venous pressure due to some obstruction from both ocular or extraocular structures. This undetermined increase in venous pulse pressure could then significantly decrease perfusion pressures and therefore further decrease oxygen supply to the retinal tissues. The investigators will therefore try to determine if there is a significant difference between the oxygen saturation of the retinal vessels in both glaucoma patients with and without a visible pulsating central vein
Interplay between the increasing IOP and decreasing blood pressure (BP) during the 24-hour period, especially in the nocturnal period, may lead to insufficient perfusion pressure of the optic nerve and contribute to the glaucomatous damage in adjunct to the antero-posterior vectorial mechanical impact on the lamina cribrosa, the translaminar pressure. Patients with progressive VF loss showed greater nocturnal BP dips than patients with stable VF. Reduced mean intraocular perfusion pressure (IOPP) was significantly associated with the extent of glaucomatous damage. How the nycthemeral IOP fluctuation influences glaucoma progression has not been studied in a prospective manner and remains to be elucidated. The purpose of this study is to assess the relationship between the 24-hour IOP fluctuation pattern and the 24-hour BP pattern in patients with primary open angle glaucoma (POAG). IOP fluctuations will be monitored with SENSIMED Triggerfish®, a portable investigational device using a contact lens sensor that monitors the IOP fluctuation continuously over 24-hours.
The purpose of the study is to prove if there is any difference in the nerve fiber layer between patients with normal- and high-tension-glaucoma with similar structural optic nerve head parameters.
Purpose To evaluate efficacy and safety of combigan(Brimonidine/Timolol) and 0.5% Timoptic (Timolol) ophthalmic solutions in normal tension glaucoma patients.