[Show abstract][Hide abstract] ABSTRACT: To investigate the effectiveness of a low vision self-management program (LVSMP) in older adults.Methods Participants(n = 153) were existing clients of a national low vision rehabilitation organisation randomly allocated to usual services (n = 60) or usual services plus LVSMP (n = 93). The LVSMP was an eight-week group program facilitated by low vision counsellors. The primary outcome was vision-specific quality of life (QoL) measured using the Impact of Vision Impairment (IVI) questionnaire. Secondary outcomes emotional well-being, self-efficacy and adaptation to vision loss were measured using the Depression, Anxiety, Stress Scale (DASS), General Self-Efficacy Scale (GSES), and Short Form Adaptation to Age-Related Vision Loss scale (AVL12).ResultsAt one and six month follow-up assessments, no significant between-group differences were found for vision-specific QoL, emotional well-being, adaptation to vision loss or self-efficacy (p > 0.05). Univariate and multivariate analyses revealed no impact of the intervention on outcome measures.Conclusions
In contrast to previous work, our study found limited benefit of a LVSM program on QoL for older adults accessing low vision services.Practice ImplicationsWhen implementing self-management programs in low vision rehabilitation settings, issues of client interest, divergence of need, program accessibility and fidelity of intervention delivery need to be addressed.
Patient Education and Counseling 11/2014; · 2.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Context: Hemoglobin A1c (HbA1c) ≥6.5% (47.5 mmol/mol) has recently been included as a criterion for the diagnosis of diabetes mellitus. It is unclear whether this criterion is appropriate in Asians. Objective: To examine the relationship between HbA1c and diabetes-specific moderate-retinopathy in Asian ethnic groups. Design, setting and participants: Four independent population: based cross-sectional studies (2004-2011) in Singapore representing the three major Asian ethnic groups (n=13,170 adults aged ≥25 years, Chinese =5,834, Malays=3,596, and Indians=3,740). Main outcome: Moderate-retinopathy was assessed from digital retinal photographs and defined as level >43 using the Early Treatment Diabetic Retinopathy Study (ETDRS) scale. Sensitivity, specificity, positive and negative predictive values (PPV, NPV), and the area under the receiver operating characteristic curve (AUC) for detecting moderate-retinopathy were compared across ethnic groups at different HbA1c cut-points. Results: HbA1c levels were higher in Indians and Malays compared to Chinese (p<0.001). The prevalence of moderate-retinopathy below HbA1c <6.5% was <1% in all ethnic groups. At HbA1c ≥6.5%, the sensitivity for detecting moderate-retinopathy was lower in Chinese compared to Indians and Malays (75.8% vs. 86.0%, 85.3%), but specificity (89.7% vs. 71.9%, 76.3%) was higher; however, PPV and NPV were similar among Chinese, Indians, and Malays (10.5%, 12.3%, 12.4%; 99.6%, 99.1%, 99.2%). The AUCs were similar across all three ethnic groups (0.861, 0.851 and 0.853). Conclusions: Our study supports the use of HbA1c for diagnosing diabetes in Asians. Despite some inter-ethnic variation in the relationship of HbA1c and retinopathy, a cut-point of 6.5% performs reasonably well in the three major Asian ethnic groups.
The Journal of clinical endocrinology and metabolism. 11/2014;
[Show abstract][Hide abstract] ABSTRACT: To objectively quantify choroidal thickness and choroidal volume using fully automated choroidal segmentation software applied to images obtained from enhanced depth imaging spectral-domain optical coherence tomography (EDI SD-OCT) in a population-based study; and evaluate the ocular and systemic determinants of choroidal thickness and choroidal volume.
[Show abstract][Hide abstract] ABSTRACT: Purpose: To describe the methodology and assess the reliability and validity of a novel computer based semi-automated software which quantifies retinal arteriolar central light reflex (CR), a hypertensive retinopathy sign, from digital retinal photographs. Methods: Digital retinal photographs from the Singapore Malay Eye Study (SiMES), a population-based cross-sectional study of 3,280 (78.7% response) persons aged 40 to 80 years, were selected. Computer-assisted software was developed to quantify retinal arteriolar central light reflex (CR) by selecting vessel edge points semi-automatically. This software then automatically computes the CR, vessel diameter, and the CR to the vessel diameter ratio (CRR). 150 randomly selected retinal photographs from SiMES participants were used for the final analysis. Reliability parameters were assessed using intra-class correlation coefficient (ICC) and Bland-Altman Plots. The criterion validity of the new method was determined by examining the association between CRR and systemic and ocular factors. Results: The ICCs for the inter-grader and intra-grader CRR measurement were 0.76 (95% confidence interval [CI]: 0.53 - 0.89) and 0.86 (95% CI: 0.67 - 0.94), respectively. The ICC for intra-visit repeatability was 0.87 (95% CI: 0.71 - 0.95). In the multivariate model, a higher CRR was independently associated with elevated mean arterial blood pressure (per 10 mmHg increase) (β=0.017, p<0.001). Conclusions: We demonstrated that quantitative assessment of retinal arteriolar wall opacification is a reliable and valid method using a new computer-assisted system. Our new CRR measurement system can provide a useful tool to study retinal arteriolar abnormalities with systemic diseases potentially.
[Show abstract][Hide abstract] ABSTRACT: Purpose: To investigate the role of epoxyeicosatrienoic acids (EETs) and prostaglandins (PGs) in retinal blood vessel calibers and vasodilation during flicker light stimulation in humans. Methods: Twelve healthy non-smokers participated in a balanced crossover study. Oral fluconazole 400 mg and dispersible aspirin 600 mg were used to inhibit production of EETs and PGs, respectively. Retinal imaging was performed 1 h after drug ingestion with the Dynamic Vessel Analyzer. Resting calibers of selected vessel segments were recorded in measurement units (MU). Maximum percentage dilations during flicker stimulation were calculated from baseline calibers. We then studied six participants each after fluconazole and aspirin ingestions at 30 min intervals for 2 h. Within-subject differences were assessed by analysis of variance and Dunnett-adjusted pairwise comparisons with significance taken at P < 0.05. Results: In crossover study participants, mean (standard deviation [SD]) arteriole and venule dilations without drug administration were 4.4 (2.0)% and 4.6 (1.7)%, respectively. Neither drug affected vasodilation during flicker stimulation. Mean (SD) resting arteriole and venule calibers on no-drug visits were 119.6 (10.6) MU and 145.7 (17.0) MU, respectively. Fluconazole reduced mean (±95% C.I.) resting venule calibers by 5.1 (4.3) MU. In repeated measures participants, neither drug affected vasodilations, but fluconazole reduced resting venule calibers over 2 h (P < 0.001). Conclusions: EETs and PGs are unlikely to be primary mediators of flicker light-induced retinal vasodilation in humans. However, EETs may play a role in the regulation of retinal vascular tone and blood flow under resting physiological conditions.
[Show abstract][Hide abstract] ABSTRACT: Purpose: The mechanisms supporting the protective relationship between a longer axial length (AL) and a decreased risk of diabetic retinopathy (DR) remain unclear. Previous studies have demonstrated reduced retinal blood flow in axial myopia, and it has been suggested that the compromised retinal capillaries in diabetes are less likely to leak and rupture as a result of this decreased flow. In this study, we investigated if reduced retinal capillary flow (RCF) is a potential mechanism underpinning this protective relationship. Methods: RCF was assessed using the Heidelberg Retinal Flowmeter in 150 eyes of 85 patients with diabetes aged 18+ years from the Royal Victorian Eye and Ear Hospital and St. Vincent's Hospital (Melbourne), Australia. AL was measured using the Intraocular Lens Master. DR was graded from two-field retinal photographs into none, mild, moderate and severe DR using the modified Airlie House classification system. Results: A total of 74 of 150 eyes (49.3%) had DR. A longer AL was associated with decreased odds of DR presence (per mm increase in AL, odds ratio [OR] 0.61, 95% confidence interval [CI] 0.41 to 0.91), and DR severity (OR: 0.65, 95% CI: 0.44 to 0.95). However, no association was found between AL and RCF (per mm increase in AL, regression coefficient [β] -1.80, 95% CI: -13.50 to 9.50) or between RCF and DR (per unit increase in RCF, OR 1.00, 95% CI 0.99 to 1.00). Conclusions: Our finding suggests that diminished RCF may not be a major mechanism underlying the protective association between axial elongation and DR.
[Show abstract][Hide abstract] ABSTRACT: Purpose: To investigate the impact of ambient room lighting on the magnitude of flicker light-induced retinal vasodilations in healthy individuals. Methods: 20 healthy non-smokers participated in a balanced 2 x 2 crossover study. Retinal vascular imaging was performed with the Dynamic Vessel Analyzer under reduced or normal ambient lighting, then again after 20 minutes under the alternate condition. Baseline calibers of selected arteriole and venule segments were recorded in measurement units (MU). Maximum percentage dilations from baseline during 20 seconds of luminance flicker were calculated from the mean of three measurement cycles. Within-subject differences were assessed by repeated measures analysis of variance with the assumption of no carryover effects and pairwise comparisons from the fitted model. Results: Mean (standard deviation [SD]) maximum arteriole dilations during flicker stimulation under reduced and normal ambient lighting were 4.8% (2.3%) and 4.1% (1.9%), respectively (P = 0.019). Maximum arteriole dilations were (mean ±95% C.I.) 0.73% ±0.59% lower under normal ambient lighting compared with reduced lighting. Ambient lighting had no significant effect on maximum venular dilations during flicker stimulation or on the baseline calibers of arterioles or venules. Conclusions: Retinal arteriole dilation in response to luminance flicker stimulation is reduced under higher ambient lighting conditions. Reduced responses with higher ambient lighting may reflect reduced contrast between the ON and OFF flicker phases. Although it may not always be feasible to conduct studies under reduced lighting conditions, ambient lighting levels should be consistent to ensure that comparisons are valid.
[Show abstract][Hide abstract] ABSTRACT: Purpose: To demonstrate the effectiveness of Hierarchical Bayesian (HB) approach in a modelling framework for association effects that accounts for standard error of vision-specific latent traits assessed using Rasch analysis. Methods: A systematic literature review was conducted in four major ophthalmic journals to evaluate Rasch analysis performed on vision-specific instruments. HB approach was used to synthesize Rasch model and multiple linear regression model for the assessment of the association effects related to vision-specific latent traits. The effectiveness of this novel HB one-stage "joint analysis" approach was compared to the frequently used two-stage "separate analysis" (traditional) approach in our simulation study. Results: Sixty-six reviewed articles performed evaluation and validation of vision-specific instruments using Rasch analysis. 86.4% (n=57) performed further statistical analyses on the Rasch-scaled data using traditional statistical methods and none took into consideration of standard error for the estimated Rasch-scaled scores. The two models on real data differed for effect size estimations and the identification of 'independent risk factors'. Simulation results showed that our proposed approach produces greater accuracy (average of 5 folds decrease in bias) with comparable power and precision in estimation of associations when compared to the frequently used two-stage "separate analysis" procedure despite accounting for greater uncertainty due to the latent trait. Conclusions:Patient reported data, using Rasch analysis techniques, do not take into account standard error in their association analyses. HB one-stage "joint analysis" is a better approach, producing accurate effect size estimations and information about the independent association of exposure variables with vision-specific latent traits.
[Show abstract][Hide abstract] ABSTRACT: Background
There are limited data available on the variables that might affect retinal vessel oxygen saturation (SO2) in diabetes. Therefore, the aim of this study is to assess factors associated with retinal oximetry values in persons with diabetes.DesignClinic-based cross-sectional studyParticipants58 persons with diabetes aged 18+ years, recruited from the University of Melbourne, the Royal Victorian Eye and Ear Hospital, and St. Vincent's Hospital (Melbourne), Australia.Methods
Retinal oximetry was performed using the oximetry module of the Vesselmap system in 92 diabetic eyes. Generalized estimating equation models were used to estimate the associations between candidate variables (age; gender; retinal capillary flow; duration of diabetes; hypertension; smoking status; presence of diabetic retinopathy; HbA1c; triglyceride; total cholesterol; finger oxygen saturation and ocular perfusion pressure) with retinal oximetry measures.Main Outcome MeasureArteriolar SO2, venular SO2 and the arterio-venous (A-V) differenceResultsOf the candidate factors assessed, only the presence of diabetic retinopathy was significantly associated with increased venular oxygen saturation and decreased arterio-venous difference in unadjusted analyses. In models adjusting for age and gender, compared to no diabetic retinopathy, the presence of diabetic retinopathy was significantly associated with greater retinal venular oxygen saturation values (β = 3.65%, 95% confidence interval: 0.67-6.63%) and decreased A-V difference (β = -2.00%, 95% confidence interval: -3.46 to -0.53%).Conclusion
In patients with diabetes, eyes with diabetic retinopathy were associated with increased venular oxygen saturation and decreased arterio-venous difference compared to eyes without diabetic retinopathy, suggesting an altered metabolic state in DR.
Clinical and Experimental Ophthalmology 07/2014; · 1.96 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Body mass index (BMI) is an established risk factor for diabetes. However, the association between BMI and diabetic retinopathy (DR) has been inconclusive. We aimed to assess the association between BMI and DR in a large population-based sample of multi-ethnic Asian adults in Singapore. We examined 2,278 adults aged ≥40 years with diabetes who participated in three population-based studies conducted from 2004 to 2011: the Singapore Malay Eye Study, the Singapore Indian Eye Study, and the Singapore Chinese Eye Study. Retinal photographs taken from both eyes were graded for any and vision-threatening (VTDR) using the modified Airlie House Classification. BMI (kg/m(2)) was categorized into normal/underweight (<25), overweight (25-29.9), and obese (≥30). The prevalence rates of any and VTDR in the study population were 35.1 % and 9.1 %, respectively. The prevalence of any and VTDR decreased with increasing categories of BMI (P trend <0.001 and 0.005). In multivariable models adjusted for potential confounders, compared to those with normal weight, the odds ratio (95 % confidence interval) of any DR was 0.71 (0.57-0.88) for overweight and 0.70 (0.53-0.92) for obese. Corresponding estimates for VTDR were 0.84 (0.59-1.21) for overweight and 0.58 (0.35-0.94) for obese. The inverse association between BMI and any DR was consistently present when BMI was analyzed as a continuous variable and in analyses stratified by ethnicity and age. In a population-based sample of multi-ethnic Asian adults, BMI levels were inversely associated with any DR and VTDR.
[Show abstract][Hide abstract] ABSTRACT: To investigate characteristics associated with screening positive for depressive symptoms among older adults accessing low-vision rehabilitation and eye-care services and to determine client acceptability of depression screening using the Patient Health Questionnaire-2 (PHQ-2) in these settings.
Australasian Journal on Ageing 05/2014; · 0.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Recent genome-wide association studies for diabetic retinopathy (DR) have identified novel single nucleotide polymorphisms associated with this potentially blinding disease. These markers could prove useful in risk profiling, if the association are validated by replication. To date, these associations have not been well assessed in independent cohorts. The objective of this study was to ascertain any association of these polymorphisms with advanced stages of DR.
A total of 463 patients who had either type 1 (n=46) or 2 (n=417) diabetes were genotyped for 24 single nucleotide polymorphisms previously implicated in DR. Cases (n=163) were defined as people with severe non-proliferative DR or proliferative DR. Control participants (n=300) with a confirmed duration of diabetes of at least five years had either no evidence of DR or only mild DR.
Two SNPs (rs1073203 and rs4838605) were found to be significantly associated with DR in patients with diabetes after adjusting for co-variants; rs1073203-G (p=0.012, odds ratio (OR)=0.317, 95% CI:0.129-0.778), rs1073203 in a dominant model (p=0.005, OR=0.251, 95% CI:0.096-0.655), rs4838605 in an additive model (p=0.047, OR=1.650, 95% CI:1.007-2.703), In a dominant model rs1073203 (p=0.027, OR=1.400, 95% CI:0.101-0.857), was significantly associated with diabetic retinopathy in type 2 diabetes after adjustment for co-variants. This study was sufficiently powered to replicate previous findings. CONCLUSIONS. This study has confirmed two variants (rs1073203 and rs4838605) are associated with advanced stages of DR in our cohort. The underlying genes in these candidate regions provide interesting future gene association targets for understanding the pathogenesis of DR.
[Show abstract][Hide abstract] ABSTRACT: Purpose: To assess factors associated with retinal oximetry values in healthy persons. Methods: Retinal oximetry readings were assessed using the oximetry module of the Vesselmap system in 100 eyes of 50 healthy subjects aged 18 to 58 years. Generalized estimating equation models were used to estimate the associations between candidate variables (age; gender; retinal capillary flow; HbA1c; triglyceride; cholesterol; ocular perfusion pressure and finger oxygen saturation [SO2]) with retinal oximetry measures (arteriolar SO2; venular SO2; and the arterio-venous [A-V] difference). Results: Of the candidate factors assessed, only age and finger SO2 were found to be significantly associated with one or more measures of retinal oximetry in crude analyses. In models adjusting for age, gender and significant factors from crude analyses; age and finger SO2 values remained significant. Age was associated with retinal arteriolar and venular SO2 values (per year increase in age, β = 0.31, 95% confidence interval [CI]: 0.15-0.48 and β = 0.26, 95% CI: 0.08-0.43; respectively), but not associated with the A-V difference. Finger SO2 values were associated with retinal arteriolar SO2 and A-V difference (per percentage change in finger SO2, β = 1.34, 95% CI: 0.40-2.28 and β = 0.74, 95% CI: 0.36-1.11; respectively), but not with venular SO2. Conclusion: In healthy persons, age was positively associated with the retinal and venular SO2 values, while finger SO2 was positively correlated with greater arteriolar SO2 and A-V difference. Our findings serve as a basis for future studies assessing retinal oximetry values in subjects under normal and pathophysiological conditions.
[Show abstract][Hide abstract] ABSTRACT: Falls result in >$1 billion in treatment, disability, lost output and mortality each year in Australia and people with cataract are at increased risk. Previous research is inconclusive; one large Australian study using linked hospital data found no protective effect of cataract surgery. We aim to examine the impact of cataract-related vision impairment on falls risk and the additional effects of delays in access to surgery, refractive management (type of spectacles and changes to spectacle prescription) and the resulting level of function, particularly binocular function which can impact balance.
A prospective, 24-month cohort study is planned involving over 700 patients aged 70 years or older with bilateral cataract presenting for surgery at five public hospital eye clinics in Sydney, Melbourne and Perth, Australia. The primary outcomes will be self-reported falls and falls requiring medical care, assessed objectively using administrative data sets. Secondary outcomes include community participation, quality of life, mood and depressive symptoms. McNemar's test will be used to evaluate differences in falls rate before, after first eye and after second eye cataract surgery. Generalised Estimating Equations linear regression analysis will be undertaken to examine factors associated with falls risk and the secondary outcomes.
With limited resources to further shorten public waiting lists, there is a need to better understand an individuals' risk of fall injury or other negative consequences while waiting for surgery. The findings of this project will inform the development of strategies to reduce falls risk in the many older people with cataract.
[Show abstract][Hide abstract] ABSTRACT: Objective
To assess the impact of visual impairment (VI) on health-related quality of life and to compare the health burden of VI and other health conditions in Singapore.
Population-based cross-sectional study.
We studied the 10 009 adults (3353 Chinese, 3397 Indians, and 3259 Malays) who underwent a comprehensive eye assessment and completed the European Quality of Life-5 Dimensions (EQ-5D) questionnaire in the Singapore Epidemiology of Eye Disease Study.
We estimated the effects of VI, obesity, hypertension, diabetes, and hyperlipidemia on the EQ-5D index score using linear regression models and the association between VI and self-reported EQ-5D health problems using logistic regression models. We compared prevalence-based quality-adjusted life-year (QALY) loss associated with VI and other health conditions. For each condition, QALY loss was calculated for 100 000 persons in 1 year using associated reduction in EQ-5D index score estimated in regression analysis as disutility.
Main Outcome Measures
The EQ-5D index score and annual QALY loss.
The EQ-5D index score decreased with increasing VI severity in all 3 ethnicities. For example, after adjusting for sociodemographic characteristics, the difference in EQ-5D index score between adults with bilateral severe VI and those without VI was −0.044 (95% confidence interval [CI], −0.089 to 0.001) in Chinese, −0.127 (95% CI, −0.237 to −0.017) in Indians, and −0.085 (95% CI, −0.148 to −0.022) in Malays. In all 3 ethnicities, VI was associated with reporting of problems in mobility (e.g., odds ratio [OR], 3.69 for Chinese with bilateral severe VI; 95% CI, 1.21–12.13) and usual activities (e.g., OR, 6.51 for Chinese with bilateral severe VI; 95% CI, 1.59–26.58). In Indians, VI was also associated with anxiety or depression (e.g., OR, 2.68 for bilateral severe VI; 95% CI, 1.11–6.50). The annual QALY loss associated with VI was 511.8 in Chinese, 608.8 in Indians, and 706.7 in Malays, greater than that associated with other health conditions examined in this study.
Visual impairment is associated with substantial health burden among Asians in Singapore. The relatively high burden of VI highlights the importance of VI prevention. The ethnic difference exhibited in this burden warrants further study.
[Show abstract][Hide abstract] ABSTRACT: The aim of the study was to assess levels of health literacy and computer skills in Chinese patients with cataract, and their impact on the doctor-patient relationship.
PLoS ONE 01/2014; 9(9):e107615. · 3.53 Impact Factor