Macular Degeneration: Yang YC

Yang YC. · Wolverhampton Eye Infirmary, Wolverhampton, WV3 9QR. · Hosp Med. · Pubmed #14964795 No free full text.

Abstract: Wet age-related macular degeneration (AMD) is the leading cause of blindness in the elderly population. Verteporfin photodynamic therapy (PDT) is significantly effective in preventing visual loss in patients with subfoveal choroidal neovascularization caused by exudative AMD. This article reviews verteporfin PDT and discusses treatment and evolving appraisal guidance.

Azab M, Boyer DS, Bressler NM, Bressler SB, Cihelkova I, Hao Y, Immonen I, Lim JI, Menchini U, Naor J, Potter MJ, Reaves A, Rosenfeld PJ, Slakter JS, Soucek P, Strong HA, Wenkstern A, Su XY, Yang YC, Anonymous00313. · No affiliation provided · Arch Ophthalmol. · Pubmed #15824216 No free full text.

Abstract: OBJECTIVE: To compare the treatment effect and safety of photodynamic therapy with verteporfin using a standard (SF) or reduced (RF) light fluence rate with that of placebo therapy in patients with subfoveal minimally classic choroidal neovascularization (CNV) with age-related macular degeneration. DESIGN: Phase 2, multicenter, double-masked, placebo-controlled, randomized clinical trial. SETTING: Nineteen ophthalmology practices in North America and Europe. PARTICIPANTS: Patients with initial best-corrected visual acuity of at least 20/250 and a lesion size of no greater than 6 Macular Photocoagulation Study (MPS) disc areas. METHODS: We randomly assigned 117 patients (1:1:1) to verteporfin infusion (6 mg/m(2)) and light application with an RF rate (300 mW/cm(2)) for 83 seconds (light dose of 25 J/cm(2)) or an SF rate (600 mW/cm(2)) for 83 seconds (light dose of 50 J/cm(2)) or to placebo infusion with RF or SF. Treatment was repeated every 3 months if the treating physician noted fluorescein leakage from CNV on angiography. Patients in whom a predominantly classic lesion developed could receive open-label standard verteporfin treatment. Best-corrected visual acuity was measured every 3 months, and angiographic changes were assessed by the Photograph Reading Center through the 3-month examination unless an ocular adverse event or conversion to a predominantly classic lesion was identified by an investigator. Safety was assessed throughout the study. All outcomes were on an intent-to-treat basis. RESULTS: One hundred three (88%) of 117 patients completed the 24-month examination. Twelve (30%) of 40 patients assigned to placebo received open-label standard verteporfin treatment after confirmation of presence of predominantly classic CNV. At month 12, a loss of at least 3 lines of visual acuity occurred in 5 (14%) of 36 eyes assigned to RF and 10 (28%) of 36 eyes assigned to SF, compared with 18 (47%) of 38 eyes assigned to placebo (RF, P = .002; SF, P = .08; RF + SF, P = .004). At month 24, this loss occurred in 9 (26%) of 34 eyes assigned to RF and 17 (53%) of 32 assigned to SF, compared with 23 (62%) of 37 eyes assigned to placebo (RF, P = .003; SF, P = .45; RF + SF, P = .03). Progression to predominantly classic CNV by 24 months was more common in the placebo group (11 [28%] of 39 patients compared with 2 [5%] of 38 in the RF group [P = .007] and 1 [3%] of 37 in the SF group [P = .002]). No unexpected ocular or systemic adverse events were identified. Treatment-related, usually transient visual disturbances were 13% with SF, 10% with placebo, and 5% with RF. CONCLUSIONS: Verteporfin therapy safely reduced the risks of losing at least 15 letters (> or =3 lines) of visual acuity and progression to predominantly classic CNV for at least 2 years in individuals with subfoveal minimally classic lesions due to age-related macular degeneration measuring 6 MPS disc areas or less. Based on the overall evidence available on verteporfin therapy for these lesions, the VIM Study Group would consider recommending verteporfin therapy for relatively small minimally classic lesions similar to those enrolled in the VIM Trial.

Karnon J, Czoski-Murray C, Smith K, Brand C, Chakravarthy U, Davis S, Bansback N, Beverley C, Bird A, Harding S, Chisholm I, Yang YC. · School of Health and Related Research, University of Sheffield, UK. · Health Technol Assess. · Pubmed #18513468 links to  free full text

Abstract: OBJECTIVES: To estimate the cost-effectiveness of screening for age-related macular degeneration (AMD) by developing a decision analytic model that incorporated and assessed all of the National Screening Committee criteria. A further objective was to identify the major areas of uncertainty in the model, and so inform future research priorities in this disease area. DATA SOURCES: Major databases were searched in March 2004 and updated in January 2005. REVIEW METHODS: Systematic literature reviews covered the epidemiology and natural history of AMD, the screening and treatment effectiveness and health-related quality of life relating to AMD. A hybrid cohort-individual sampling model was implemented to describe the range of pathways between the incidence of age-related maculopathy (ARM) and death via clinical presentation and treatment at different stages of the disease. As significant shortfalls in the data available from the literature were apparent, so a range of primary data sources were also used to populate the model. To obtain estimates for the value of parameters deemed to be within an expert's remit, data describing some parameters were elicited from relevant experts. The data identified informed probability distributions describing the uncertainty around the model parameters. To incorporate joint parameter uncertainty (i.e. correlations between parameters), the AMD natural history model was calibrated probabilistically. Randomly sampled sets of input parameters were assigned weights representing the accuracy of their predictions of a set of observed model outputs. The analysis of the AMD screening model estimated the costs, numbers of quality-adjusted life-years (QALYs) and cases of blindness in a general population sample of 50-year-olds over the remainder of their lifetime, for 16 alternative screening options (including no screening). The reference case analysis incorporated current treatment options of laser photocoagulation and photodynamic therapy. Sensitivity analyses describing six alternative sets of intervention strategies, based on horizon scanning of potential future treatments for AMD, were also undertaken. RESULTS: There remains significant uncertainty about whether any form of screening for AMD is cost-effective. However, annual screening from age 60 years seems to provide the highest mean net benefits, but this is based on a cost-effectiveness estimate that has very poor precision (high levels of uncertainty). The probabilistic sensitivity analysis shows that the 95% credible interval for annual screening from age 60 years ranges from this option dominating the previous option to an incremental cost per QALY of over 0.5 million pounds sterling. Plotting a cost-effectiveness acceptability frontier shows that although annual screening from age 60 years has the highest net benefits at a value of QALY of 30,000 pounds sterling, the associated probability of this option being the most cost-effective option is only around 20%. The sensitivity analyses around potential future treatment options indicate that screening may become more cost-effective with the new treatments. CONCLUSIONS: The conclusions focus on the interpretation of the results from the perspective of defining the major areas of uncertainty, which were defined as disease progression, rates of clinical presentation, screening test and optician effectiveness, treatment effectiveness, and costs of blindness. Future research may be best targeted at assessing how routine data may be used to describe clinical presentation rates of ARM. Other potential studies include a pilot study of the effectiveness of screening and opticians' referral patterns for AMD and a costing study of blindness as a continuum of association with deterioration in vision.

Bhatnagar A, Musadiq M, Yang YC. · Wolverhampton Eye Infirmary, Compton Road, Wolverhampton, WV3 9QR, UK. · Eye. · Pubmed #15877088 No free full text.

Abstract: Photodynamic therapy (PDT) has been shown in large studies to be capable of achieving closure of choroidal neovascularization (CNV), thereby resulting in stabilization of visual acuity. We report a series of four patients with classic CNV treated with PDT with good initial result but subsequent severe visual loss that may be related to a change in the morphology of the subretinal scar.

Arora S, Musadiq M, Mukherji S, Yang YC. · Wolverhampton and Midlands Counties Eye Infirmary, Wolverhampton, Midlands, UK. · Eye. · Pubmed #15131676 No free full text.

Abstract: BACKGROUND AND PURPOSE: Patients are increasingly well informed about the availability of antioxidant products and the claims made for their benefits in age-related macular degeneration (AMD). Consequently, their use is becoming widespread. The purpose of this study is to conduct a survey of the commonly encountered products, and to compare their ingredients with the current Age-Related Eye Disease Study (AREDS) recommendations. METHODS: A search was undertaken for products sold as 'eye nutrients' at local pharmacies and health food shops, and for products advertised via the Internet. Information about these products was collated and analysed. RESULTS: We identified 22 eye nutrient products. Analysis of their constituents showed that, although over 75% contained all the constituents used in AREDS, only two matched the dosage profiles recommended in the study. CONCLUSION: The authors draw no conclusion on the efficacy of nutritional supplements in the prevention of AMD. In order to advise their patients, ophthalmologists should be familiar with these products. The compiled list in this paper should provide a useful reference for them.