Active clinical trials for "Retinal Diseases"

Introduction: Diabetic mellitus (DM) is a prevalent disease in Hong Kong (HK) and diabetic retinopathy (DR) is one of the most common complications of DM. Screening for DR is a cost-effective method to identify patients who are at risk of vision loss so that timely treatment can be provided to patients. In Hong Kong, the Hospital Authority has recently set up screening services (RAMP) in the government outpatient clinics and all DM patients attending these clinics will be screened at least once every two years and some every six months, according to their individual risks. However, those diabetic patients who attend the private sector for their primary care may not have access to this service. Aim: This study from the University of Hong Kong aims to determine the characteristics of a sustainable approach to setting up an effective and quality-controlled screening service for DR in the private primary care sector of Hong Kong and to estimate the potential benefit to be gained in terms of impact on avoidable vision loss, costs of care and potential for further development of this model in chronic disease care. Methods:A screening centre is being set up and a randomised study carried out in which screening will be offered at three different fee levels to subjects recruited by their general practitioner (GP). The following data will be collected (a) willingness to attend screening at the different fee levels (b) screening findings in terms of DR and other eye diseases (c) risk factors and other characteristics of those screened and unscreened. The information will allow us to estimate the level of fee which best combines effectiveness with sustainability in the longer term.

Type 2 Diabetes (TD2) is the leading cause of new cases of preventable blindness in these countries (and the gold-standard treatment, laser photocoagulation has proven to be effective in preventing vision loss at the end stage of eye disease due to proliferative diabetic retinopathy (PDR) that occurs in 3 to 6 % of the cases.Therefore, the ongoing search for predictive factors of sight threatening stages of diabetic retinopathy has become more important. Previous studies that have examined candidate predictive factors for diabetic eye disease have mostly focused on systemic risk factors leading to PDR. Among various clinical parameters, increased HbA1c % levels, uncontrolled blood pressure, diabetes duration, neuropathy and elevated triglycerides have been associated with PDR. Some genetic factors may also account for the development of PDR and are prospectively considered in this study .

The aim of this study is to compare the effectiveness of identifying diabetic retinopathy using tele-medicine based Digital Retinal Imaging in Diabetes Clinics with that of the conventional referral system. Hypothesis: Tele-medicine based digital retinal imaging involving a diabetes centre will identify proportionately more diabetic patients with DR and lead to higher acceptance rate with subsequent ophthalmic referral and management

Introduction: There is no debate that people with diabetes should be screened for the development of retinopathy which can threaten their sight. However, there is no routine screening for retinopathy in Hong Kong at present. Many overseas countries find that they miss a large proportion of their target population and, with reliance on co-payments for screening, as is the case with the limited opportunistic screening at present, the cost-effectiveness of any routine service in Hong Kong could be reduced as is predicted by Hart's inverse care law. Aim: This study will determine the potential cost-effectiveness of screening for retinopathy in Hong Kong under a free system and one in which a co-payment is charged. Methods: Primary care patients attending General Outpatient Clinics on Hong Kong Island for their routine diabetic care will randomly be offered screening either at no charge or with the normal co-payment of $65. Those who are willing and unwilling to be screened will be compared for their clinical, lifestyle and socioeconomic characteristics and those unwilling will be asked their reasons. The uptake of screening at no fee and with a payment will be compared as will the prevalence of retinopathy in the two fee groups. Subsequent screening at one year will be offered at the same fee and uptake again compared. The principal analyses will (a) identify the characteristics of those willing to be screened and reasons for not being screened (b) the uptake of screening when a co-payment is charged compared to when it is free (c) whether there is a difference in the prevalence of retinopathy between the group willing to pay and those who accept free screening and (d) the uptake of re-screening in year 2. The resulting cost-effectiveness model will use these data, the cost data collected during the study and overseas data on benefits of treatment to model the cost-effectiveness of screening for retinopathy in Hong Kong if it were to be offered free or with a co-payment. This information will be important to determine the most cost-effective means of implementing this preventative strategy to preserve sight and quality of life.

Vascular Endothelial Growth Factor (VEGF) is a dimeric glycoprotein, naturally expressed in epithelial and tumor cells (1). Normal Retinal vascularization has two phases: In the first fase, cells of mesenquimatous origin form the first superficial plexus (14-21 weeks of gestation). In the second phase, denominated "angiogenesis phase", the superficial and deep capillary plexus are formed (15,20). The Retinopathy of Prematurity (ROP) was described for the first time in 1942 (4), at the present moment it is a public health problem in the developing countries. The International Classification of ROP classifies it in 5 stages, dividing it in 3 anatomical zones. It is a public health problem that continuous without having an effective prophylaxis. The early diagnosis and treatment in thresholds stages have changed the prognosis of this disease (11,12).

Diabetes has reached epidemic levels in North America and with it, diabetic retinopathy is increasingly affecting the vision of millions of people. Despite treatment many patients still have vision loss that cannot be improved medically or with prescription eyeglasses. Our study is going to look at an FDA Class 1 Exempted visual aid that uses augmented reality to help people see better.

Aflibercept, a recombinant fusion antibody that binds to all subtypes of VEGF and PlGF, has been shown to induce effective regression of retinal neovascularization secondary to PDR but there had been lack of a well-structured prospective study about adjunctive use of intravitreal injection of Aflibercept (IVA) to reduce postoperative VH in PPV for PDR. In this study, we aim to assess the effect of preoperative IVA on the incidence of postoperative VH after PPV for PDR.

To determine if a novel intraocular injection guide (IIG) reduces patient discomfort during and after intravitreal injections.

To determine the vitreous levels of fractalkine, cysteine-rich 61 (Cyr61), and VEGF in patients with PDR. Verifying that it is greater to that found in non-diabetic patients with different non-angiogenetic diseases.

Long-standing diabetes is often complicated by retinopathy. The mechanisms that induce the development of diabetic retinopathy are incompletely understood and include alterations in bone marrow derived vasculogenic cells called "endothelial progenitor cells". Fenofibrate is a PPAR-alpha agonist used for the treatment of mixed dislipidemia and hypertriglyceridemia. In a trial conducted in type 2 diabetic patients, the drug fenofibrate has reduced retinopathy-related endpoints suggesting a direct effect of the drug on the mechanisms that drive the development of this complication. Herein, the investigators hypothesize that fenofibrate treatment can increase circulating EPC levels in diabetic patients with retinopathy, compared to placebo.