Macular Degeneration: Wong TY

Wong TY, Rogers SL. · No affiliation provided · Am J Ophthalmol. · Pubmed #17601430 No free full text.

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Wong TY. · No affiliation provided · Br J Ophthalmol. · Pubmed #11090467 links to  free full text

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Wong TY, Hyman L. · Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia. · Am J Ophthalmol. · Pubmed #18984085 No free full text.

Abstract: PURPOSE: To review major findings of population-based studies in ophthalmology, to summarize key questions, and to highlight future directions for this study design. DESIGN: Summary and critical analysis of major population-based studies in eye diseases. METHODS: Literature review and interpretation. RESULTS: In the last 30 years, there have been many population-based studies in ophthalmology conducted in the United States and other countries around the world. These studies have provided information on the epidemiology of visual loss and the major eye diseases associated with visual loss; the risk factors; and the socioeconomic burden of eye disease. Population-based studies remain the most valid to determine the prevalence and incidence of a disease, and the population-attributable risk of new risk factors, including the interaction of genetic markers with systemic and environmental factors. Repeated surveys over time may also demonstrate impact of preventive strategies. CONCLUSIONS: Population-based studies have provided substantial data on the frequency and impact of the major eye diseases in the community. This study design will continue to have an important role in addressing key questions of why eye diseases occur, who is at highest risk, and what preventive and therapeutic strategies are necessary to eliminate these diseases.

Wang S, Wang JJ, Wong TY. · Centre for Eye Research Australia, University of Melbourne, Victoria, Australia. · Surv Ophthalmol. · Pubmed #18929762 No free full text.

Abstract: Alcohol consumption is a modifiable lifestyle factor, but there is uncertainty regarding its association with eye diseases in adults. A relationship between alcohol consumption and an increased risk of cataract has been reported from cross-sectional studies, but several prospective cohort studies have not found this association. Prospective population-based study findings suggest that heavy alcohol consumption is weakly related to an increased risk of age-related macular degeneration. Reports of an association of alcohol consumption and diabetic retinopathy have been limited mainly to cross-sectional data. There is little evidence of an association between alcohol consumption and glaucoma, and findings of association between alcohol consumption and increased intraocular pressure have been inconsistent. This review shows there is no consistent evidence supporting a major role of moderate alcohol consumption in the development or progression of common eye diseases. The effect of heavy alcohol consumption on different ocular conditions needs to be clarified, although heavy consumption of alcohol has significant detrimental social, mental, and medical consequences.

Wirostko B, Wong TY, Simó R. · Pfizer, Inc., New York, NY, USA. · Prog Retin Eye Res. · Pubmed #18929676 No free full text.

Abstract: Intraocular delivery of anti-vascular endothelial growth factor (VEGF) therapies is now used widely to treat age-related macular degeneration, and is currently undergoing evaluation in clinical trials for treatment of diabetic retinopathy. An important aspect of anti-VEGF treatment is that while the agents are injected into the vitreous cavity, they may be absorbed systemically, thus potentially affecting systemic VEGF levels. Systemic VEGF-A and the interplay between membrane-bound VEGF receptors and the soluble form of VEGF-R1 are key to angiogenesis, vasculogenesis, neurogenesis and hemodynamics. These cellular processes are regulated by complicated negative and positive feedback loops, many of which are disrupted and altered in diabetes. The VEGF protein, mRNA, as well as the actual VEGF receptor levels, appear to be impaired in diabetes in microvascular and macrovascular vessel beds. What is not clear is the exact role and influence that these levels have on an organ's function. In some organ systems, elevated VEGF levels act as a pathologic angiogenic stimulus (i.e., ocular neovascularization) whereas in others, low levels of VEGF activity leads to pathology (i.e., cardiomyopathy, wound healing and peripheral neuropathy). Diabetic patients have a higher risk of hypertension and proteinuria, two surrogate markers of systemic VEGF inhibition. Certain intraocular anti-VEGF treatments could therefore have an adverse effect in this population by possibly affecting circulating and organ-specific VEGF and VEGF receptor levels.

Chong EW, Kreis AJ, Wong TY, Simpson JA, Guymer RH. · Centre for Eye Research Australia, University of Melbourne, Victoria, Australia. · Arch Ophthalmol. · Pubmed #18541848 links to  free full text

Abstract: OBJECTIVE: To systematically review the evidence on dietary omega-3 fatty acid and fish intake in the primary prevention of age-related macular degeneration (AMD). METHODS: Seven databases were systematically searched with no limits on publication year or language using standardized criteria. Randomized controlled trials and prospective cohort, case-control, and cross-sectional studies were included. Of 2754 abstracts identified, 3 prospective cohort, 3 case-control, and 3 cross-sectional studies met the criteria. Measures of associations were pooled quantitatively using meta-analytic methods. RESULTS: Nine studies provided data on a total sample of 88 974 people, including 3203 AMD cases. A high dietary intake of omega-3 fatty acids was associated with a 38% reduction in the risk of late AMD (pooled odds ratio [OR], 0.62; 95% confidence interval [CI], 0.48-0.82). Fish intake at least twice a week was associated with a reduced risk of both early AMD (pooled OR, 0.76; 95% CI, 0.64-0.90) and late AMD (pooled OR, 0.67; 95% CI, 0.53-0.85). CONCLUSIONS: Although this meta-analysis suggests that consumption of fish and foods rich in omega-3 fatty acids may be associated with a lower risk of AMD, there is insufficient evidence from the current literature, with few prospective studies and no randomized clinical trials, to support their routine consumption for AMD prevention.

Baker ML, Hand PJ, Wang JJ, Wong TY. · Centre for Eye Research Australia, University of Melbourne, Victoria, Australia. · Stroke. · Pubmed #18309171 links to  free full text

Abstract: BACKGROUND AND PURPOSE: The retinal and cerebral vasculature share similar anatomic, physiological, and embryological characteristics. We reviewed the literature, focusing particularly on recent population-based studies, to examine the relationship between retinal signs and stroke. Summary of Review- Hypertensive retinopathy signs (eg, focal retinal arteriolar narrowing, arterio-venous nicking) were associated with prevalent stroke, incident stroke, and stroke mortality, independent of blood pressure and other cerebrovascular risk factors. Diabetic retinopathy signs (eg, microaneurysms, hard exudates) were similarly associated with incident stroke and stroke mortality. Retinal arteriolar emboli were associated with stroke mortality but not incident stroke. There were fewer studies on the association of other retinal signs such as retinal vein occlusion and age-related macular degeneration with stroke, and the results were less consistent. CONCLUSIONS: Many retinal conditions are associated with stroke, reflecting possible concomitant pathophysiological processes affecting both the eye and the brain. However, the incremental value of a retinal examination for prediction of future stroke risk remains to be determined.

Chong EW, Kreis AJ, Wong TY, Simpson JA, Guymer RH. · Centre for Eye Research Australia, The University of Melbourne, Victoria, Australia. · Am J Ophthalmol. · Pubmed #18242575 No free full text.

Abstract: PURPOSE: To review systematically the evidence currently available on alcohol consumption and the risk of age-related macular degeneration (AMD). DESIGN: Systematic review and meta-analysis of observational studies. METHODS: Seven databases were searched systematically with no limits on the year or language of publication for prospective cohort studies. References identified from pertinent reviews and articles also were retrieved. Two reviewers independently searched the above databases and selected the studies using prespecified standardized criteria. These criteria included appropriate adjustment for age and smoking in the analysis. Of the 441 studies identified initially, five cohort studies met the selection criteria. Data extraction and study quality evaluation were performed independently by two reviewers and results were pooled quantitatively using meta-analytic methods. RESULTS: The five cohort studies included 136,946 people, among whom AMD developed in 1923 (1,513 early and 410 late). Pooled results showed that heavy alcohol consumption was associated with an increased risk of early AMD (pooled odds ratio, 1.47; 95% confidence interval, 1.10 to 1.95), whereas the association between heavy alcohol consumption and risk of late AMD was inconclusive. There were insufficient data to evaluate a dose-response association between alcohol consumption and AMD or the association between moderate alcohol consumption and AMD. CONCLUSIONS: Heavy alcohol consumption (more than three standard drinks per day) is associated with an increased risk of early AMD. Although this association seems to be independent of smoking, residual confounding effects from smoking cannot be excluded completely.

Chong EW, Wong TY, Kreis AJ, Simpson JA, Guymer RH. · Centre for Eye Research Australia, University of Melbourne, Victoria 3002, Australia. · BMJ. · Pubmed #17923720 links to  free full text

Abstract: OBJECTIVE: To evaluate the effectiveness of dietary antioxidants in the primary prevention of age related macular degeneration (AMD). DESIGN: Systematic review and meta-analysis. DATA SOURCES: Search of seven databases without limits on year or language of publication, and retrieval of references in pertinent reviews and articles. METHODS: Two reviewers independently searched the databases and selected the studies, using standardised criteria. Randomised clinical trials and prospective cohort studies were included. Of the 4192 abstracts initially identified, 12 studies (nine prospective cohort studies and three randomised clinical trials) met the selection criteria and were included. Data extraction and study quality evaluation were independently reviewed, using standardised criteria. Results were pooled quantitatively using meta-analytic methods. RESULTS: The nine prospective cohort studies included 149 203 people, with 1878 incident cases of early AMD. The antioxidants investigated differed across studies, and not all studies contributed to the meta-analysis of each antioxidant. Pooled results from prospective cohort studies indicated that vitamin A, vitamin C, vitamin E, zinc, lutein, zeaxanthin, alpha carotene, beta carotene, beta cryptoxanthin, and lycopene have little or no effect in the primary prevention of early AMD. The three randomised clinical trials did not show that antioxidant supplements prevented early AMD. CONCLUSIONS: There is insufficient evidence to support the role of dietary antioxidants, including the use of dietary antioxidant supplements, for the primary prevention of early AMD.

Mohamed Q, Gillies MC, Wong TY. · Centre for Eye Research Australia, University of Melbourne and Royal Victorian Eye and Ear Hospital, Melbourne, Australia. · JAMA. · Pubmed #17712074 links to  free full text

Abstract: CONTEXT: Diabetic retinopathy (DR) is the leading cause of blindness in the working-aged population in the United States. There are many new interventions for DR, but evidence to support their use is uncertain. OBJECTIVE: To review the best evidence for primary and secondary intervention in the management of DR, including diabetic macular edema. EVIDENCE ACQUISITION: Systematic review of all English-language articles, retrieved using a keyword search of MEDLINE (1966 through May 2007), EMBASE, Cochrane Collaboration, the Association for Research in Vision and Ophthalmology database, and the National Institutes of Health Clinical Trials Database, and followed by manual searches of reference lists of selected major review articles. All English-language randomized controlled trials (RCTs) with more than 12 months of follow-up and meta-analyses were included. Delphi consensus criteria were used to identify well-conducted studies. EVIDENCE SYNTHESIS: Forty-four studies (including 3 meta-analyses) met the inclusion criteria. Tight glycemic and blood pressure control reduces the incidence and progression of DR. Pan-retinal laser photocoagulation reduces the risk of moderate and severe visual loss by 50% in patients with severe nonproliferative and proliferative retinopathy. Focal laser photocoagulation reduces the risk of moderate visual loss by 50% to 70% in eyes with macular edema. Early vitrectomy improves visual recovery in patients with proliferative retinopathy and severe vitreous hemorrhage. Intravitreal injections of steroids may be considered in eyes with persistent loss of vision when conventional treatment has failed. There is insufficient evidence for the efficacy or safety of lipid-lowering therapy, medical interventions, or antivascular endothelial growth factors on the incidence or progression of DR. CONCLUSIONS: Tight glycemic and blood pressure control remains the cornerstone in the primary prevention of DR. Pan-retinal and focal retinal laser photocoagulation reduces the risk of visual loss in patients with severe DR and macular edema, respectively. There is currently insufficient evidence to recommend routine use of other treatments.

Wong TY, Wong T, Chakravarthy U, Klein R, Mitchell P, Zlateva G, Buggage R, Fahrbach K, Probst C, Sledge I. · Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia. · Ophthalmology. · Pubmed #17675159 No free full text.

Abstract: PURPOSE: To describe the natural history and progression of visual loss in eyes with untreated neovascular age-related macular degeneration (AMD). DESIGN: Systematic review and meta-analysis. PARTICIPANTS: Four thousand three hundred sixty-two untreated neovascular AMD patients from published interventional studies. METHODS: A systematic review of the literature from 1980 to August 2005 was performed. Studies reporting disease progression outcomes for untreated patients with neovascular AMD were included. Outcome measures were summarized using simple counts and means. Random effects meta-analyses were conducted and tests of heterogeneity were performed where appropriate. MAIN OUTCOME MEASURES: Changes in visual acuity (VA) loss, development of comorbidities, and fellow eye involvement. RESULTS: Fifty-three primary studies were included. Nearly half of the studies (28) were randomized clinical trials. The quality of the studies was high, with over 80% providing level I or II evidence. Mean baseline VA among study patients was 0.64 logarithm of the minimum angle of resolution (logMAR) (approximately 20/87 Snellen). The mean VA change in logMAR progressed from 0.1 (1 line lost) at 3 months to 0.3 (2.7 lines lost) after 12 months and 0.4 (4 lines lost) after 24 months. The proportion of patients who developed severe vision loss (>6 lines) from baseline increased from 21.3% at 6 months to 41.9% by 3 years. The proportion of patients with VA worse than logMAR 1.0 (20/200 Snellen) increased from 19.7% at baseline to 75.7% by 3 years. Neovascular AMD developed in the fellow eye in 12.2% of patients by 12 months and in 26.8% by 4 years. Meta-analyses of vision outcome by subtype of neovascular AMD were not possible. CONCLUSIONS: A doubling of the visual angle of presenting VA may be expected to occur in the year after initial presentation in eyes with untreated neovascular AMD. No conclusions can be drawn as to the differences in rates of disease progression by neovascular AMD subtype. The diversity of reporting formats, paucity of long-term natural history data, and heterogeneity among the reported clinical studies impose limits to the clear understanding of long-term prognosis for visual function in neovascular AMD.

McIntosh RL, Mohamed Q, Saw SM, Wong TY. · Centre for Eye Research Australia, University of Melbourne, Melbourne, VIC, Australia. · Ophthalmology. · Pubmed #17397923 No free full text.

Abstract: TOPIC: To assess the evidence on interventions to improve visual acuity (VA) and to treat macular edema and/or neovascularization secondary to branch retinal vein occlusion (BRVO). CLINICAL RELEVANCE: Branch retinal vein occlusion is the second most common retinal vascular disease. METHODS/LITERATURE REVIEWED: English and non-English articles were retrieved using a keyword search of Medline (1966 onwards), Embase, the Cochrane Collaboration, the National Institute of Health Clinical Trials Database, and the Association for Research in Vision and Ophthalmology Annual Meeting Abstract Database (2003-2005). This was supplemented by hand searching references of review articles. Two investigators independently identified all randomized clinical trials (RCTs) with more than 3 months' follow-up. RESULTS: From 4332 citations retrieved, 12 RCTs were identified. There were 5 RCTs on laser photocoagulation. Grid macular laser photocoagulation was effective in improving VA in 1 large multicenter RCT, the Branch Vein Occlusion Study (BVOS), but 2 smaller RCTs found no significant difference. The BVOS showed that scatter retinal laser photocoagulation was effective in preventing neovascularization and vitreous hemorrhage in patients with neovascularization, but a subsequent RCT found no significant effect. Randomized clinical trials evaluating intravitreal steroids (n = 2), hemodilution (n = 3), ticlopidine (n = 1), and troxerutin (n = 1) showed limited or no benefit. CONCLUSIONS: There is limited level I evidence for any interventions for BRVO. The BVOS showed that macular grid laser photocoagulation is an effective treatment for macular edema and improves vision in eyes with VA of 20/40 to 20/200, and that scatter laser photocoagulation can effectively treat neovascularization. The effectiveness of many new treatments is unsupported by current evidence.

Wong TY, Wong T, Mitchell P. · Centre for Eye Research Australia, University of Melbourne, Australia. · Lancet. · Pubmed #17276782 No free full text.

Abstract: Hypertension has a range of effects on the eye. Hypertensive retinopathy refers to retinal microvascular signs that develop in response to raised blood pressure. Signs of hypertensive retinopathy are frequently seen in adults 40 years and older, and are predictive of incident stroke, congestive heart failure, and cardiovascular mortality--independently of traditional risk factors. Hypertension is also a major risk factor for the development of other retinal vascular diseases, such as retinal vein and artery occlusion, and ischaemic optic neuropathy. High blood pressure increases the risk of both development of diabetic retinopathy and its progression. Adequate control of blood pressure has been proven in randomised clinical trials to reduce vision loss associated with diabetic retinopathy. Finally, hypertension has been implicated in the pathogenesis of glaucoma and age-related macular degeneration. Recognition of the ocular effects of blood pressure could allow physicians to better manage patients with hypertension, and to monitor its end-organ effects.

Wong TY, Loon SC, Saw SM. · Centre for Eye Research Australia, University of Melbourne, 32 Gisborne Street, Victoria 3002, Australia. · Br J Ophthalmol. · Pubmed #16547337 links to  free full text

Abstract: In the past decade, several large population based studies have provided new information on the prevalence of visual impairment and the major age related eye diseases in Asia. These include epidemiological studies from India, Taiwan, Mongolia, Singapore, and Japan. In particular, the epidemiology of refractive errors and glaucoma has been well characterised, providing insights not only into the public health implications of these conditions, but also into anatomical changes of the eye with ageing. In contrast, there are few well conducted population based studies on diabetic retinopathy and age related macular degeneration in Asia, two conditions that are likely to be important causes of blindness in the future.

Baker ML, Wang JJ, Rogers S, Klein R, Kuller LH, Larsen EK, Wong TY. · Centre for Eye Research Australia, University of Melbourne, East Melbourne, Victoria, Australia. · Arch Ophthalmol. · Pubmed #19433718 No free full text.

Abstract: OBJECTIVE: To describe the association of cognitive function and dementia with early age-related macular degeneration (AMD) in older individuals. METHODS: This population-based study included 2,088 persons aged 69 to 97 years who participated in the Cardiovascular Health Study. The AMD was assessed from retinal photographs based on a modified Wisconsin AMD grading system. Cognitive function was assessed using the Digit Symbol Substitution Test (DSST) and the Modified Mini-Mental State Examination. Participants were also evaluated for dementia using detailed neuropsychological testing. RESULTS: After controlling for age, sex, race, and study center, persons with low DSST scores (lowest quartile of scores, < or =30) were more likely to have early AMD (odds ratio, 1.38; 95% confidence interval, 1.03-1.85) than were persons with higher DSST scores. In analyses further controlling for education, systolic blood pressure, total cholesterol level, diabetes mellitus, smoking status, and apolipoprotein E genotype, this association was stronger (odds ratio, 2.00; 95% confidence interval, 1.29-3.10). There was no association of low Modified Mini-Mental State Examination scores, dementia, or Alzheimer disease with early AMD. CONCLUSIONS: In this older population, cognitive impairment may share common age-related pathogenesis and risk factors with early AMD.

Wang FH, Liang YB, Zhang F, Wang JJ, Wei WB, Tao QS, Sun LP, Friedman DS, Wang NL, Wong TY. · Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Lab, Beijing, China. · Ophthalmology. · Pubmed #19168222 No free full text.

Abstract: PURPOSE: To describe the age- and gender-specific prevalence, characteristics, and severity of diabetic retinopathy (DR) in a rural population in northern China. DESIGN: A population-based cross-sectional study. PARTICIPANTS: A total of 6830 Han Chinese aged 30 years and older from 13 villages of Yongnian County, Handan City, Hebei Province, China. METHODS: All participants underwent a standardized interview, a comprehensive eye examination, and fasting blood glucose testing according to the American Diabetes Association diagnostic criteria (fasting plasma glucose >or=7.0 mmol/l). Retinal photographs obtained after pupil dilation were graded for the presence and severity of DR according to the modified Early Treatment Diabetic Retinopathy Study classification system. MAIN OUTCOME MEASURES: Any DR, retinopathy grades, macular edema, or vision-threatening retinopathy. RESULTS: Of the 6830 eligible individuals participating in the study, 5597 (81.9%) had fasting blood glucose results available. Of these, 387 participants (6.9%) were diagnosed with diabetes mellitus, including 247 subjects with new diabetes mellitus (NDM) and 140 subjects with known diabetes mellitus (KDM). For these, gradable photographs were available for 368 subjects (95.1%). The overall prevalence of DR was 43.1% (95% confidence interval, 38.1-48.4) and was higher in persons with KDM (65.2%) than NDM (33.5%). The prevalence of proliferative DR, macular edema, and vision-threatening retinopathy was 1.6%, 5.2%, and 6.3%, respectively, with 12.1% with KDM having untreated vision-threatening DR. No age- or gender-related differences were present. The prevalence of DR was strongly related to duration of disease. CONCLUSIONS: Our study reports a high prevalence of DR among adults 30 years and older with diabetes in rural China. On the basis of estimates obtained from our study, we projected that in rural China, 21.1 million persons aged 30+ years have diabetes and 9.2 million have DR, including 1.3 million with vision-threatening DR. There is a pressing need for appropriate screening and management of diabetes and its complications in rural China.

Peeters A, Magliano DJ, Stevens J, Duncan BB, Klein R, Wong TY. · Department of Epidemiology and Preventive Medicine, Monash University, Victoria, Australia. · Arch Ophthalmol. · Pubmed #19001224 No free full text.

Abstract: OBJECTIVE: To examine the association between changes in waist-hip ratio (WHR), a measure of abdominal obesity, and age-related macular degeneration (AMD). METHODS: A total of 12 515 persons from a population-based cohort study, aged 45 to 64 years in 1987 to 1989, were followed up over 6 years. The percentage change in WHR during follow-up was ranked into sex-specific deciles; an increase in WHR was defined as the top 10% of change and a decrease in WHR as the bottom 10%. The association of increased or decreased WHR and presence of AMD at follow-up was determined using logistic regression adjusting for potential confounders. RESULTS: The average change in WHR was an increase of 2%, ranging from a decrease of 44% to an increase of 102%. A decrease in WHR of 3% or more was associated with 29% lower odds of any AMD (odds ratio = 0.71; 95% confidence interval, 0.52-0.97). This effect was most pronounced among obese participants at baseline, where a decrease in WHR was associated with 59% lower odds of AMD (odds ratio = 0.41; 95% confidence interval, 0.20-0.82). CONCLUSIONS: Middle-aged persons who had a 3% or greater reduction in WHR over time were less likely to have AMD, particularly among those who were initially obese.

Lavanya R, Wong TY, Aung T, Tan DT, Saw SM, Tay WT, Wang JJ, Anonymous00098. · Centre for Eye Research Australia, University of Melbourne, 32 Gisborne Street, East Melbourne, VIC 3002 Australia. · Br J Ophthalmol. · Pubmed #18927226 No free full text.

Abstract: AIM: The aim of the study was to describe the prevalence and visual outcomes of cataract surgery in an urban Asian population. METHODS: This was a population-based study of 3280 Singapore Malays aged 40-80 years (response rate 78.7%). Participants had a standardised interview and comprehensive ocular examination. Poor post-operative visual outcome was defined as visual acuity </=20/60 in operated eyes of unilateral cataract extractions or in the better-seeing eye of bilateral cataract extractions. Factors associated with poor visual outcome were assessed. RESULTS: Of 3280 participants, 284 (men 52.3%) had unilateral cataract extractions (age-standardised prevalence 4.7%, 95% CI 4.2% to 5.4%) and 154 persons (54%) had bilateral extractions. Older age, male sex and the presence of diabetes were significant factors associated with having had cataract surgery. Poor visual outcomes were present in 10.8% of the operated eyes using best-corrected visual acuity. Diabetic retinopathy (25.5%), glaucoma (17%), age-related macular degeneration (14.9%) and posterior capsular opacification (14.9%) were the main causes of poor visual outcome after surgery. Under-corrected refractive error accounted for 60% of patients with post-operative presenting visual acuity of </=20/60. CONCLUSIONS: Five per cent of the sample of the Malay population aged 40-80 years in Singapore had cataract surgery. One in ten had post-operative best-corrected visual acuity of 20/60 or worse, largely related to concomitant retinal diseases.

Kaushik S, Wang JJ, Flood V, Tan JS, Barclay AW, Wong TY, Brand-Miller J, Mitchell P. · Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute, University of Sydney, Sydney, Australia. · Am J Clin Nutr. · Pubmed #18842800 No free full text.

Abstract: BACKGROUND: Dietary factors are known risk factors for age-related macular degeneration (AMD) -- the leading cause of visual loss among persons aged > or =65 y. High-glycemic-index diets have been hypothesized as a risk factor for AMD, but prospective data are unavailable. OBJECTIVE: The objective was to examine the association between dietary glycemic index and the 10-y incidence of AMD in the Blue Mountain Eye Study population. DESIGN: This was a population-based cohort study with 3,654 participants (> or =49 y) examined at baseline (1992-1994); 2,335 patients were reexamined after 5 y and 1952 after 10 y. The Wisconsin System was used to grade 10-y incident early and late AMD from retinal photographs. A food-frequency questionnaire was used to collect dietary information at baseline, and an Australian database was used to calculate the mean glycemic index. RESULTS: Over 10 y, 208 of 1,810 persons (cumulative incidence: 14.1%) developed early AMD. After age, smoking, other risk factors, and dietary constituents were adjusted for, a higher mean dietary glycemic index was associated with an increased 10-y risk of early AMD in a comparison of quartiles 1 and 4 [relative risk (RR): 1.77; 95% CI: 1.13, 2.78; P for trend = 0.03]. Conversely, a greater consumption of cereal fiber (RR: 0.68; 95% CI: 0.44, 1.04; P for trend = 0.05) and breads and cereals (predominantly lower glycemic index foods such as oatmeal) (RR: 0.67; 95% CI: 0.44, 1.02; P for trend = 0.03) was associated with a reduced risk of incident early AMD. No relation was observed with late AMD. CONCLUSIONS: A high-glycemic-index diet is a risk factor for early AMD -- the recognized precursor of sight-threatening late AMD. Low-glycemic-index foods such as oatmeal may protect against early AMD.

Jeganathan VS, Kawasaki R, Wang JJ, Aung T, Mitchell P, Saw SM, Wong TY. · Centre for Eye Research Australia, University of Melbourne, Melbourne, Victoria, Australia. · Am J Ophthalmol. · Pubmed #18760764 No free full text.

Abstract: PURPOSE: To investigate the relationship between retinal vascular caliber and age-related macular degeneration (AMD). DESIGN: Population-based cross-sectional study. METHODS: Three thousand two hundred and eighty (78.7% response rate) Malay Singaporeans aged 40 to 80 years residing in 15 districts of Singapore underwent retinal photography. Retinal vessel caliber was measured from retinal photographs using a validated computer-based technique. AMD was assessed following a modified Wisconsin Age-Related Maculopathy Grading System. RESULTS: Retinal data were available from 3,265 subjects (99.5% of 3,280) for this study. Early and late AMD prevalence were 4.9% (n = 160) and 0.7% (n = 23) of the population, respectively, or in 205 (3.1%) and 30 (0.5%) eyes examined, respectively. After controlling for age and arteriolar caliber, wider venular caliber was associated with higher prevalence of early AMD (odds ratio [OR] per one standard deviation [SD] increment in venular caliber, 1.53; 95% confidence interval [CI], 1.13 to 2.09). This association remained significant after further adjustment for gender, smoking, hypertension, diabetes, and body mass index (OR per one SD, 1.52; 95% CI, 1.11 to 2.09). There was no significant association between retinal arteriolar caliber and early AMD, or between arteriolar or venular caliber and late AMD. CONCLUSIONS: Wider venular caliber was associated independently with early AMD. This finding may suggest that pathogenic processes linking to wider venular caliber be shared by early AMD and common cardiovascular risk factors such as inflammation, dyslipidemia, and endothelial dysfunction.

Cackett P, Wong TY, Aung T, Saw SM, Tay WT, Rochtchina E, Mitchell P, Wang JJ. · Singapore Eye Research Institute, Singapore; Singapore National Eye Center, Singapore. · Am J Ophthalmol. · Pubmed #18723144 No free full text.

Abstract: PURPOSE: To assess associations between smoking and cardiovascular risk factors and prevalent age-related macular degeneration (AMD) in the Singapore Malay population. DESIGN: Population-based, cross-sectional study. METHODS: A total of 3,280 Malay adults age 40 to 80 years were included in the study. Early and late AMD signs were graded from retinal photographs following Wisconsin system. All participants had interview, systemic examination, and laboratory investigations to determine smoking status and cardiovascular risk factors. RESULTS: A total of 3,265 participants had gradable photos, 21 (0.6%) with late AMD and 169 (5.2%) with early AMD. After adjusting for age and gender, current smokers were significantly more likely to have late AMD (odds ratio [OR], 3.79; 95% confidence interval [CI], 1.40 to 10.23). This association was stronger among those who currently smoked >5 packs of cigarettes per week (OR, 9.35; 95% CI, 2.49 to 35.08). CONCLUSIONS: Smoking was associated with a higher late AMD prevalence in Malays, consistent with findings from studies in White populations.

Wong TY, Chong EW, Wong WL, Rosman M, Aung T, Loo JL, Shen S, Loon SC, Tan DT, Tai ES, Saw SM, Anonymous00339. · Centre for Eye Research Australia, The University of Melbourne, 32 Gisborne St, Melbourne 3002, Victoria, Australia. · Arch Ophthalmol. · Pubmed #18695104 links to  free full text

Abstract: OBJECTIVE: To describe the prevalence and causes of low vision and blindness in a Malay population. METHODS: A population-based, cross-sectional study of 3280 participants of Malay ethnicity, aged 40 to 79 years, was conducted. Participants underwent standardized ophthalmic assessments to determine (1) presenting and best-corrected visual acuity according to US and modified World Health Organization definitions of blindness and low vision and (2) the primary causes of visual impairment. RESULTS: Of 4168 eligible individuals, 3280 participated in the study (78.7%). The population-weighted prevalence of bilateral blindness was 0.3% and of bilateral low vision, 4.4% (US definition of presenting visual acuity). After best-corrected visual acuity, the population-weighted prevalence of bilateral blindness was reduced to 0.1% and bilateral low vision to 1.0%. Cataract was the main cause of presenting unilateral (38.9%) and bilateral (65.2%) blindness, whereas undercorrected refractive error was the main cause of presenting unilateral (68.8%) and bilateral (52.2%) low vision. Diabetic retinopathy, age-related macular degeneration, and glaucoma were the other leading causes of blindness and low vision. CONCLUSIONS: The age-standardized prevalences of bilateral blindness and low vision in a Malay population were lower when compared with other Asian studies. Undercorrected refractive error and cataract are the leading causes of visual impairment among the Malay adult population in Singapore.

Wickremasinghe SS, Michalova K, Gilhotra J, Guymer RH, Harper CA, Wong TY, Qureshi S. · Medical Retina Unit, Royal Victorian Eye and Ear Hospital, Melbourne, Australia. · Ophthalmology. · Pubmed #18672291 No free full text.

Abstract: PURPOSE: Bevacizumab is an inhibitor of vascular endothelial growth factor widely used as an "off-label" treatment of neovascular age-related macular degeneration (AMD), despite the lack of clinical trial data on efficacy or safety of this drug. We describe acute intraocular inflammation after intravitreous injection of bevacizumab for the treatment of neovascular AMD. DESIGN: A retrospective case series. PARTICIPANTS: Patients with neovascular AMD treated with intravitreous injection of bevacizumab from clinical practices in 2 states (Victoria and South Australia) in Australia. METHODS: We retrospectively reviewed cases of acute intraocular inflammation after intravitreous injection of bevacizumab for the treatment of neovascular AMD. MAIN OUTCOME MEASURES: The detection and description of inflammation in a large cohort of patients. RESULTS: There were 14 cases (11 women and 3 men), from a total of 1278 injections given. The mean age of patients was 83.7 years (range, 74-98). The majority had a prior injection of bevacizumab, with a mean number of injections of 2.7 (range, 1-6). Most patients presented within 24 hours of intravitreous injection, with rapid reduction in vision, but minimal discomfort. There were associated signs of ocular inflammation in the anterior and posterior segments of the eye. Visual acuity at presentation was substantially reduced compared with the preinjection acuity, although the vision rapidly improved with treatment over a period of 7-25 days toward preinjection visual acuity. CONCLUSIONS: Intravitreous injection of bevacizumab for the treatment of neovascular AMD may be associated with acute intraocular inflammation. Differentiation from infectious endophthalmitis is important for appropriate management of this condition.

Cackett P, Tay WT, Aung T, Wang JJ, Shankar A, Saw SM, Mitchell P, Wong TY. · Singapore Eye Research Institute, Singapore. · Br J Ophthalmol. · Pubmed #18664503 No free full text.

Abstract: BACKGROUND/AIMS: Low socio-economic status is increasingly being identified as a risk marker for chronic diseases, but few studies have investigated the link between socio-economic factors and age-related macular degeneration (AMD). The present study aimed to assess the association between socio-economic status and the prevalence of AMD. METHODS: A population-based cross-sectional study of 3280 (78.7% response rate) Malay adults aged 40-80 years residing in 15 south-western districts of Singapore. AMD was graded from retinal photographs at a central reading centre using the modified Wisconsin AMD scale. Early and late AMD signs were graded from retinal photographs following the Wisconsin grading system. Socio-economic status including education, housing type and income were determined from a detailed interview. RESULTS: Of the participants, 3265 had photographs of sufficient quality for grading of AMD. Early AMD was present in 168 (5.1%) and late AMD in 21 (0.6%). After adjusting for age, gender, smoking, hypertension, diabetes and body mass index, participants with lower educational levels were significantly more likely to have early AMD (multivariate OR 2.2, 95% CI 1.2 to 4.0). This association was stronger in persons who had never smoked (multivariate OR 3.6, 95% confidence CI 1.4 to 9.4). However, no association with housing type or income was seen. CONCLUSIONS: Low educational level is associated with a higher prevalence of early AMD signs in our Asian population, independent of age, cardiovascular risk factors and cigarette smoking.

Kawasaki R, Wang JJ, Mitchell P, Aung T, Saw SM, Wong TY, Anonymous00181. · Centre for Eye Research Australia, University of Melbourne, Australia. · Br J Ophthalmol. · Pubmed #18658173 No free full text.

Abstract: BACKGROUND/AIMS: To describe the prevalence and risk factors of epiretinal membranes (ERM) in Asian Malays and to compare this with a white population. METHODS: The Singapore Malay Eye Study examined 3280 persons (78.7% response rate) aged 40-80 years in Singapore during 2004-6. ERM were graded from retinal photographs using standardised procedures at the University of Sydney, and rates were compared with those from the Blue Mountains Eye Study (BMES). RESULTS: Of the 3,280 participants, 3,265 had sufficient quality photographs for grading. The age-standardised prevalence of ERM was 7.9% (95% CI 7.1 to 8.7%) in the Singapore Census population. The prevalence of ERM was higher in Malays than in Caucasians from the BMES (age-standardised prevalence: 15.8% (CI 14.2 to 17.2%) in Malays vs 6.8% (CI 5.9 to 7.6%) in Caucasians). Of the 384 persons with ERM, 124 (32.3%) had secondary ERM. Age, female gender, hyperopia and narrower retinal arteriolar diameter were associated with higher prevalence of ERM, after adjusting for age and/or gender. CONCLUSIONS: The prevalence of ERM in Asian Malays was higher than that in the Caucasians. Risk factors for ERM were older age, female gender, hyperopic refraction and narrower retinal arteriolar diameter.