View clinical trials related to Glaucoma.
Filter by:Boston keratoprosthesis (KPro) is a piece of specialized plastic that replace sick cornea (transparent structure at the front of the eye) in patients who have failed or those who are expected to have poor results with traditional corneal transplantation. While the Kpro can offer dramatic improvement in vision, it is also associated with several complications. Glaucoma (optic nerve damage due to high pressure inside the eye) is one of the most common complications after KPro surgery and can potentially cause irreversible vision loss. The implantation of a glaucoma drainage device (GDD), a tiny tube that drains the liquid inside the eye by bypassing the natural drainage system, is an effective option to lower the eye pressure in patients with KPro. Given the frequency and potentially devastating effects of glaucoma among KPro patients, some surgeons recommend to put in a GDD as a preventative measure. However, there is no consensus on when is the best timing to perform such surgery in relation to the Boston Kpro surgery. Hypothesis: For patients undergoing the Boston KPro surgery, implanting a GDD simultaneously, at the time of surgery, is more efficacious than at 6 months later, in the prevention of the progression of glaucoma and in maintaining better visual functions. Methods: The investigators aim to recruit 40 patients over 4 years. Recruited patients will be randomly assigned to 2 groups: 1) simultaneous GDD implantation at the Boston KPro surgery, and 2) GDD implantation 6 months after the Boston KPro surgery. Once recruited, patients will be followed before the KPro surgery, postoperative day 1, week 1, month 1, 3, 6 and 12. Standard ophthalmological exam will be performed at each visit. Additional non-invasive glaucoma tests and evaluation (visual fields and optic nerve photo) will be performed on day 1, month 1, 3, 6 and 12. For patients assigned to group 2, a GDD will be implanted 6 months after the KPro surgery. They will have additional follow-ups on post-GDD surgery day 1, week 1 and month 1. Results of visual acuity, visual fields, optic nerve evaluation and complications will be compared between the two groups to determine the better timing of GDD implantation.
Clinical Retina research studies often collect aqueous samples in hopes of estimating levels of drug or cytokines in the vitreous. Little is known about how well vitreous and aqueous correlate. This study will collect vitreous and aqueous samples at the same time to evaluate and compare drug and cytokine levels. The overall objective of this study is to evaluate the molecular concentration of growth factors, cytokines and chemokines in human aqueous humor and vitreous samples collected from individuals undergoing pars plana vitrectomy for tractional retinal detachment secondary to proliferative diabetic retinopathy, exudative or tractional retinal detachment secondary to macular degeneration, macular hole or neovascular glaucoma.
Glaucoma is an optic neuropathy in which the main risk factor is intraocular pressure (IOP). The search for other variables involved in glaucoma pathogenesis and progression has identified both systemic and ocular signs of vascular dysfunction in glaucoma patients, such as migraine, peripheral vasospasm, systemic hypotension and cerebral microvascular ischemia. Ocular blood flow studies using Color Doppler Imaging (CDI) technology has demonstrated blood velocities and increased vascular resistance (RI) to exist in such patients when compared to healthy controls. However, a CDI examination provides far more additional information, such as arterial pulsatility (PI) and mean blood velocities (MFV). While these have been used for decades now to study cerebral arteries vasoreactivity, little is known about how these variables are changed in glaucoma patients. We have recently demonstrated that these variables can be used to identify a change in the normal vascular activity when there is increased resistance. In glaucoma patients, a cutpoint in RI of the retrobulbar arteries could be determined beyond which PI increased significantly. This sharp increase in the PI has been used as an indirect signal that the vessel's ability to buffer a decreased perfusion pressure has been surpassed. The normal response to a decreased perfusion in a vascular territory with autoregulation is an increase in dilation in the downstream microcirculation, increasing cross section area in an attempt to keep a steady MFV. As PI is calculated using the vessel's MFV [PI = (PSV-EDV)/MFV], it is highly sensitive to changes in this variable. As such, the cutpoints we have identified in glaucoma patients are therefore an indirect assessment of the vessel's autoregulation limit. While our data could provide the rational as to why these RI values are associated with progression, the clinical question arises as to whether these cutpoints can be modulated by topical glaucoma therapy. As some medications such as carbonic anhydrase inhibitors have been found to have a positive effect in disease progression in what appears to be a non-IOP related effect, we considered the hypothesis that these drugs could have a positive impact on the ocular's microcirculation vasoactive response, potentially enabling to keep a steady MFV into higher values of vascular resistance.
Objective perimetry can better monitor visual field defects in retinal dystrophy and Glaucoma patients than conventional subjective perimetry. The PLR ( Pupil Light Reflex to short and long wavelength stimuli should be significantly lower compared to healthy participants in areas of visual field defects in retinal dystrophy and Glaucoma patients.
The specific aims of the clinical studies are to: - Develop a directional high-resolution OCT and OCT angiography prototype to improve imaging of structure and perfusion. - Validate wide-field OCT and OCT angiography parameters to improve early glaucoma detection. - Simulate visual field results by combining structural and angiography OCT data. - Assess abilities of above technologies and OCT-derived parameters on predicting glaucoma detection, conversion, and progression.
The purpose of this study is to determine if lowering the pressure inside the eye improves blood flow to the eye.
To investigate the effect of patterned laser trabeculoplasty (PLT) compared to selective laser trabeculoplasty (SLT) on intraocular pressure (IOP) in treatment naiv patients suffering from open-angle glaucoma or ocular hypertension. Values for IOP will be measured at baseline, 1 day and 1 month post-interventional as well as 2, 3, 6, 9, 12, 18 and 24 months after treatment. - Trial with medical device
The need for low vision services (LVS) will increase exponentially over the coming years due to the anticipated and exponential growth in the ageing population in Singapore and a rise in chronic non-communicable eye diseases. Finding the best evidenced-based management for chronic eye diseases contributing to low vision (LV) is therefore crucial. Improving patient responsibility is the key to managing LV effectively.1 This means achieving optimum self management (SM).2 However, there are currently no LV SM programs in Singapore and none has been evaluated using a randomized controlled trial (RCT) design, the gold standard methods to evaluate health interventions. The aims of this study are to assess the effectiveness of the 'Living Successfully with Low Vision (LSLV)' program in improving quality of life (QoL) in 160 elderly people with LV attending the Singapore National Eye Centre (SNEC) LV clinic. Of these, 80 will be randomly allocated to receive the LSLV 4-week SM program while the remaining 80 will receive the usual care. Comparisons will be made to determine the efficacy of the LSLV program. QoL, self-efficacy, emotional well being, and vision-specific distress will be assessed 2 weeks after training, and at six months and 12 months post intervention. This study will be the first evidenced-based RCT investigating the effectiveness of a novel vision-specific self-management strategy to improve QoL. It will also adopt a longitudinal design where the effectiveness of these interventions will be evaluated at 12 months-the first follow-up assessment of that duration at both national and international levels. Furthermore this will be the first study to characterize and profile the patients where the effect of the program did not demonstrate an improvement in both primary and secondary outcomes six months after its completion. The future clinical implications of this study include the potential to implement a successful model of LV rehabilitation in other tertiary centres around the country.
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
It is a comparative study of Safety and Efficacy of Canaloplasty and Non-penetrating Deep Sclerectomy Combined With Phacoemulsification to Treat Glaucoma and Cataract. It is a Randomised, Prospective Study.