Ecosse L Lamoureux

Duke-NUS Graduate Medical School Singapore, Tumasik, Singapore

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Publications (236)723.69 Total impact

  • Value in Health 05/2015; 18(3):A254. DOI:10.1016/j.jval.2015.03.1478 · 2.89 Impact Factor
  • Value in Health 05/2015; 18(3):A261. DOI:10.1016/j.jval.2015.03.1519 · 2.89 Impact Factor
  • Jonathan E Noonan, Ecosse L Lamoureux, Marc Sarossy
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    ABSTRACT: Blood flow in the retina is intrinsically regulated to meet the metabolic demands of its constituent cells. Flickering light or stationary contrast reversals induce an increase in blood flow within seconds of the stimulus onset. This phenomenon is thought to compensate for an increase in ganglion cell activity and energy consumption. Ganglion cell activity is in turn dependent on signals from photoreceptors, bipolar cells, horizontal cells and amacrine cells. The physiological properties of these neurons determine how each type is affected by a particular light characteristic. Neuronal activity then triggers the release of signalling molecules that dilate local blood vessels and increase blood flow. Nitric oxide has been implicated as an important mediator, but metabolites of arachidonic acid may also be involved. Detailed elucidation of these mechanisms, together with advances in imaging technology, may facilitate the use of neurovascular tests to improve the detection of retinal damage in pathological conditions. This article is protected by copyright. All rights reserved.
    Clinical and Experimental Ophthalmology 03/2015; DOI:10.1111/ceo.12530 · 1.95 Impact Factor
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    ABSTRACT: To determine the longitudinal impact of specific coping strategies on vision-related quality of life (VRQoL) in patients with low vision. A single group, longitudinal study, utilising telephone-administered interviews conducted at baseline, 3-and 6-months with patients (visual acuity <6/12 in the better eye) recruited from low vision services. The Coping Strategy Indicator (CSI) assessed three strategies used specifically in relation to vision related problems: avoidant coping, problem-solving coping, and seeking social support. VRQoL was assessed using the Impact of Vision Impairment (IVI) questionnaire, which comprises two domains: vision-related functioning and vision-related emotional well-being. We used multivariable mixed linear regression, including time as an independent variable to assess change in VRQoL. The study comprised 162 patients (Mean age = 69.8 years, 66% female), most with age-related macular degeneration (42%) and moderate vision impairment (41%; ˂6/18-6/60). Multivariable mixed linear regression showed that avoidant coping was a significant determinant of decline in vision-related functioning (β = -0.11, 95% confidence interval [CI] -0.22 to -0.01, p = 0.036) and emotional well-being (β = -0.29, 95% CI -0.45 to -0.13, p ˂ 0.001) over a 6 month period. Our findings showed that avoidant coping has a detrimental impact on VRQoL over time. Low vision specialists should be aware of their patients' coping strategies and encourage them to engage in active rather than avoidant coping to deal with the impact of their vision impairment. Copyright © 2015 by Association for Research in Vision and Ophthalmology.
    Investigative ophthalmology & visual science 03/2015; DOI:10.1167/iovs.14-16223 · 3.66 Impact Factor
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    ABSTRACT: To evaluate the effectiveness of problem-solving interventions on psychosocial outcomes in vision impaired adults. A systematic search of randomised controlled trials (RCTs), published between 1990 and 2013, that investigated the impact of problem-solving interventions on depressive symptoms, emotional distress, quality of life (QoL) and functioning was conducted. Two reviewers independently selected and appraised study quality. Data permitting, intervention effects were statistically pooled and meta-analyses were performed, otherwise summarised descriptively. Eleven studies (reporting on eight trials) met inclusion criteria. Pooled analysis showed problem-solving interventions improved vision-related functioning (standardised mean change [SMC]: 0.15; 95% CI: 0.04-0.27) and emotional distress (SMC: -0.36; 95% CI: -0.54 to -0.19). There was no evidence to support improvements in depressive symptoms (SMC: -0.27, 95% CI: -0.66 to 0.12) and insufficient evidence to determine the effectiveness of problem-solving interventions on QoL. The small number of well-designed studies and narrow inclusion criteria limit the conclusions drawn from this review. However, problem-solving skills may be important for nurturing daily functioning and reducing emotional distress for adults with vision impairment. Given the empirical support for the importance of effective problem-solving skills in managing chronic illness, more well-designed RCTs are needed with diverse vision impaired samples. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
    Patient Education and Counseling 01/2015; 98(5). DOI:10.1016/j.pec.2015.01.013 · 2.60 Impact Factor
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    ABSTRACT: The regulation of miR-126 by rs4636297 single nucleotide polymorphism (SNP) has been implicated in the pathogenesis of neovascularisation by promoting vascular endothelial growth factor, suggesting it could be associated with sight threatening diabetic retinopathy (STDR), but has not been previously investigated or reported. A case control study of 531 individuals with diabetes was genotyped for the rs4636297 SNP, using the Sequenom iPLEX Gold chemistry. STDR included people with severe non-proliferative diabetic retinopathy (NPDR) or proliferative diabetic retinopathy (PDR). Association was tested using logistic regression analysis, adjusting for confounding variables. In an additive model, the A allele of rs4636297 SNP is significantly associated with STDR compared to people with none or mild diabetic retinopathy (DR) (odds ratio (OR) = 2.02, 95% confidence interval (CI) = 1.22-3.35, p = 0.006). The A allele of rs4636297, known to be the non-functional allele for post-translational regulation of miR-126, is associated with STDR. This finding suggests that this locus would be a potential therapeutic target for inhibiting the development of DR. © The Author(s) 2015.
    Diabetes & Vascular Disease Research 01/2015; 12(2). DOI:10.1177/1479164114560160 · 3.04 Impact Factor
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    ABSTRACT: To objectively quantify the thickness of peripapillary choroid using spectral-domain optical coherence tomography (SD-OCT) with enhanced depth imaging (EDI) followed by a novel automated choroidal segmentation software in Asian eyes and to evaluate its systemic and ocular determinants. We recruited 520 subjects (1040 eyes) from the Singapore Malay Eye Study, a cross-sectional population-based study. Subjects underwent standardised detailed ophthalmic examination including SD-OCT (Spectralis) with EDI for measurement of peripapillary choroidal thickness (PPCT). The mean age of the subjects was 66.7±10.4 years (range 47-88 years) and the mean spherical equivalent was -0.01±2.28 D (range -18.50 to +7.00 D). The intra-session repeatability of PPCT measurements at four quadrants using automated choroidal segmentation software was excellent (intraclass correlation coefficient 0.9998-0.9999). The overall mean PPCT was 136.2±56.8 µm. Peripapillary choroid showed geographical differences among the four quadrants, being thickest in the superior quadrant (150.5±59.6 µm), followed by the nasal (143.5±58.4 µm) and temporal quadrants (139.4±68.9 µm), and thinnest in the inferior quadrant (111.3±51.7 µm). Among the range of ocular and systemic factors studied, shorter axial length (p=0.002), younger age (p=0.018), lower triglyceride level (p=0.015) and the presence of diabetes (p=0.036) were the only significant predictors of thicker peripapillary choroid. Using novel automated choroidal segmentation software, we provide reliable objective measurements of PPCT in a population-based setting. Shorter axial length, younger age, lower triglyceride levels and the presence of diabetes are the factors independently associated with thicker PPCT. These factors should be taken into consideration when interpreting Spectralis EDI SD-OCT-based PPCT measurements in clinics. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to
    British Journal of Ophthalmology 01/2015; DOI:10.1136/bjophthalmol-2014-306152 · 2.81 Impact Factor
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    ABSTRACT: Purpose. We examined the association of CKD defined by serum creatinine, serum cystatin C, and albuminuria with moderate diabetic retinopathy (DR). Methods. We examined 1,119 Indian adults with diabetes, aged 40–80 years, who participated in the Singapore Indian Eye Study (2007–2009), a population-based cross-sectional study. The associations of CKD defined by each of the three markers alone and in combination with moderate DR were examined using logistic regression models adjusted for potential confounding factors including duration of diabetes, smoking, body mass index, systolic blood pressure, and HbA1c. Results. The prevalence of moderate DR was significantly higher among those with CKD defined by triple markers (41.1%) compared to CKD defined separately by creatinine (26.6%), cystatin C (20.9%), and albuminuria (23.4%). People with CKD defined by triple markers had a fourteenfold higher odds of moderate DR (OR (95% CI) = 13.63 (6.08–30.54)) compared to those without CKD by any marker. Nearly half (48.7%) of participants with cystatin C ≥ 1.12 mg/L have moderate DR. Conclusions. CKD defined by a triple marker panel was strongly associated with moderate DR in this Asian population with diabetes.
    Journal of Diabetes Research 01/2015; · 3.54 Impact Factor
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    ABSTRACT: To investigate the acceptance and preferences rates of 3 sustained drug delivery systems in glaucoma patients. A cross-sectional study involving 250 Chinese patients recruited from outpatient glaucoma clinics in Singapore using an interviewer-administered survey. Beliefs toward medicines, eye drops, illness perception, medication adherence, and health literacy were assessed using validated questionnaires. After receiving standard information on the 3 sustained drug delivery systems, that is, subconjunctival, intracameral, and punctal routes; each route's acceptance and attitudes were determined. The subconjunctival (acceptance: 61.6%, n=154), intracameral (acceptance: 57.2%, n=143), and punctal (acceptance: 63.2%, n=158) routes were willing to be accepted by the majority of the interviewed patients. Among those, 78.6%, 79.1%, and 78.5% were willing to pay an equal or higher cost compared with their current eye drops for the subconjunctival, intracameral, and punctal plug routes, respectively. Independent factors associated with the acceptance for subconjunctival, intracameral, and punctal plug routes included: male sex (P=0.007, 0.014, 0.046, respectively), patients not on health care subsidies (P=0.022, 0.002, 0.016, respectively), and bilateral glaucoma disease (P=0.003, 0.013, 0.004, respectively). A total of 120 (48.0%) patients ranked punctal plug placement as the preferred route for sustained drug delivery followed by subconjunctival (n=76, 30.4%) and intracameral (n=54, 21.6%) routes. Sustained drug delivery for the medical treatment of glaucoma is an acceptable alternative to daily eye drop administration by most Singaporean Chinese individuals in this study. Male patients, nonsubsidized patients, and those with bilateral glaucoma were independently associated with preference of these 3 alternative routes of administration to traditional glaucoma drops.
    Journal of Glaucoma 01/2015; DOI:10.1097/IJG.0000000000000197 · 2.43 Impact Factor
  • Investigative ophthalmology & visual science 01/2015; 56(3):2002. DOI:10.1167/iovs.15-16697 · 3.66 Impact Factor
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    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; 98(2). DOI:10.1016/j.pec.2014.11.008 · 2.60 Impact Factor
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    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.
    Journal of Clinical Endocrinology &amp Metabolism 11/2014; 100(2):jc20142498. DOI:10.1210/jc.2014-2498 · 6.31 Impact Factor
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    ABSTRACT: To examine the impact of glaucoma and visual acuity (VA) and visual field (VF) losses on psychosocial functioning (PF). Cross-sectional study. We compared PF between 192 participants with bilateral glaucoma with VA or VF losses and 40 controls from a tertiary eye hospital clinic in Singapore. Glaucoma was defined using the Hodapp-Anderson-Parish criteria. Four psychosocial outcomes of the Glaucoma Quality of Life 36 questionnaire were psychometrically assessed using Rasch analysis. Multivariate regression was performed to determine the independent impact of glaucoma and VA and VF losses on PF. The impact of VA and VF on PF were evaluated by restricted cubic spline analysis. Anxiety, self-image, psychological well-being, and confidence in health care. The mean age of participants was 66.2±11.0 years, and 63% were male. In the better eye, VA and mean deviation were Snellen 20/25 and -8.89±6.52 dB, respectively. In multivariate models, glaucoma patients had 63.0% greater anxiety (95% confidence interval [CI], -66.0% to -61.2%; P < 0.001), 71.0% lower self-image (95% CI, -74.1% to -68.5%; P < 0.001), 38.3% less psychological well-being (95% CI, -37.4% to -39.0%; P < 0.001), and 32.4% reduced confidence in health care than patients without glaucoma. The worst VA and VF categories had the most reduced PF (range, 26.0%-81.5%; P < 0.001 for all associations) compared with controls. With worsening VA, there was a linear increase in anxiety (P = 0.009) and decrease in self-image (P = 0.005). With worsening VF from 0 to -12.1 dB (P = 0.003), anxiety increased before plateauing. Self-image decreased as VF worsened from 0 to -10 dB (P < 0.001), and confidence in health care decreased when VF worsened from 0 to -9.3 dB (P = 0.008). However, self-image and confidence in health care actually improved at greater levels of VF loss beyond these thresholds. Glaucoma negatively affects PF. Early stage glaucoma with mild VF loss adversely affects anxiety, self-image, and confidence in health care. As VA worsens in advanced glaucoma, anxiety further increases and self-image deteriorates. Ophthalmologists and glaucoma patients need to be aware that both VA and VF losses at different stages of glaucoma negatively impact PF. Copyright © 2014 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.
    Ophthalmology 11/2014; 122(3). DOI:10.1016/j.ophtha.2014.09.030 · 6.17 Impact Factor
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    ABSTRACT: PURPOSE: 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. DESIGN: Prospective cross-sectional study. METHODS: Participants ranging in age from 45 to 85 years were recruited from the Singapore Malay Eye Study-2 (SiMES-2), a follow-up population-based study. All participants (n = 540) underwent a detailed ophthalmic examination, including EDI SD OCT for measurements of thickness and volume of the choroid. RESULTS: The intrasession repeatability of choroidal thickness at 5 measured horizontal locations and macular choroidal volume using automated choroidal segmentation software was excellent (intraclass correlation coefficient; 0.97-0.99). Choroid was significantly thicker under the fovea (242.28 +/- 97.58 mu m), followed by 3 mm temporal (207.65 +/- 80.98 mu m), and was thinnest at 3 mm nasal (142.44 +/- 79.19 mu m) location. The mean choroidal volume. at central macular region (within a circle of 1 mm diameter) was 0.185 +/- 0.69 mm(3). Among the range of ocular and systemic factors studied, age, sex, and axial length were the only significant predictors of choroidal thickness and choroidal volume (all P < .05). CONCLUSIONS: Using a new automated choroidal segmentation software, we provide fast, reliable, and objective measurements of choroidal thickness and volume in a population-based sample. Male sex, younger age, and shorter axial length are the factors independently associated with thicker choroid and larger choroidal volume. These factors should be taken into consideration when interpreting EDI SD OCT-based choroidal thickness measurements in clinics.
    American Journal of Ophthalmology 11/2014; 159(2). DOI:10.1016/j.ajo.2014.10.034 · 4.02 Impact Factor
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    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.
    Investigative Ophthalmology &amp Visual Science 10/2014; 55(12). DOI:10.1167/iovs.14-14125 · 3.66 Impact Factor
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    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.
    Investigative Ophthalmology &amp Visual Science 10/2014; 55(10). DOI:10.1167/iovs.14-14947 · 3.66 Impact Factor
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    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.
    Investigative Ophthalmology &amp Visual Science 09/2014; 55(10). DOI:10.1167/iovs.14-15137 · 3.66 Impact Factor
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    ABSTRACT: Purpose 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. Methods We undertook a cross-sectional study of cataract patients scheduled for cataract extraction procedures in Guangdong Province, China. Generic health literacy was assessed using 3 established screening questions. Adequate computer skills was determined if patients had used a computer and routinely used search engines on the Internet. Socio-demographic measures (e.g., age, sex, education) were obtained from a standardized interview. Participants who indicated that they could not understand what their doctors mean were considered to have had poor patient-physician communications. Results Of the 211 participants, 92 (43.6%) had inadequate health literacy and 204 (96.7%) inadequate computer skills. In multivariate analysis, females were more likely to have inadequate health literacy (odds ratio = 2.5, 95% confidence intervals [CI]: 1.3 to 4.7). People with inadequately health literacy were more likely to have a poor patient-physician communication (odds ratio = 3.5, 95% CIs: 1.3 to 9.0). Similar associations were found for inadequate computer skills. Conclusion Chinese elderly patients with cataract have inadequate health literacy and very limited computer skills, which place them at high risk of misunderstanding and mismanaging their ocular conditions. Patient education information other than online materials may improve the eye care and outcomes of these patients.
    PLoS ONE 09/2014; 9(9):e107615. DOI:10.1371/journal.pone.0107615 · 3.53 Impact Factor
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    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. Design Population-based cross-sectional study. Participants 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. Methods 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. Results 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. Conclusions 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.
    Ophthalmology 09/2014; 121(9). DOI:10.1016/j.ophtha.2014.03.017 · 6.17 Impact Factor
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    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.
    Investigative Ophthalmology &amp Visual Science 08/2014; 55(9). DOI:10.1167/iovs.14-14940 · 3.66 Impact Factor

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  • 2013–2015
    • Duke-NUS Graduate Medical School Singapore
      • Centre for Quantitative Medicine
      Tumasik, Singapore
    • University of Bonn
      • Department of Ophthalmology
      Bonn, North Rhine-Westphalia, Germany
  • 2004–2015
    • Royal Victorian Eye and Ear Hospital
      Melbourne, Victoria, Australia
  • 2014
    • National University Health System
    • University of Vic
      Vic, Catalonia, Spain
  • 2003–2014
    • University of Melbourne
      • • Centre for Eye Research Australia
      • • Department of Ophthalmology
      Melbourne, Victoria, Australia
  • 2009–2013
    • Victoria University Melbourne
      Melbourne, Victoria, Australia
    • L V Prasad Eye Institute
      Bhaganagar, Andhra Pradesh, India
  • 2008–2013
    • Centre for Eye Research Australia
      Melbourne, Victoria, Australia
  • 2009–2012
    • Singapore Eye Research Institute
      Tumasik, Singapore
    • Singapore National Eye Centre
      Tumasik, Singapore
  • 2011
    • The Chinese University of Hong Kong
      • Department of Ophthalmology and Visual Sciences
      Hong Kong, Hong Kong
    • National University of Singapore
      Tumasik, Singapore
  • 2008–2009
    • Flinders University
      • • Department of Ophthalmology
      • • Flinders Medical Centre
      Tarndarnya, South Australia, Australia
  • 2001–2003
    • Deakin University
      Geelong, Victoria, Australia