[Show abstract][Hide abstract] ABSTRACT: This study reports the prevalence of visual impairment in persons with chronic kidney disease (CKD) and the associations of CKD with visual impairment and major ocular diseases, diagnosed based on comprehensive ophthalmological examination. There is a high burden of major eye diseases in persons with CKD, with nearly one in two suffering from visual impairment. Cataract and retinopathy, both independently associated with CKD, are potentially reversible causes of VI, especially if treated early. The evidence suggests a need for early eye screening in these high-risk individuals.
[Show abstract][Hide abstract] ABSTRACT: Diabetic retinopathy (DR) may evolve from retinal neurovascular dysfunction and oxidative stress. We therefore investigated the effects of euglycaemic (6 mmol/l) and hyperglycaemic clamps (15 mmol/l) with insulin infusions (6 pmol/kg/min), with or without vitamin C (2 g intravenous), on pattern electroretinogram (PERG) and flicker-induced vasodilation responses in 12 adults with type 1 diabetes. The PERG ratio (0.8° vs. 7° checks) increased by (mean [95% C.I.]) 0.31 (0.03 - 0.59) after hyperglycaemia with vitamin C. Venule maximum dilations were absolutely increased by 1.7 (0.5 - 3.0) % after euglycaemic clamps. Arteriole maximum dilations were non-significantly larger with hyperglycaemia and vitamin C (P = 0.07 by ANOVA). Insulin, and possibly vitamin C, may improve retinal neurovascular function in type 1 diabetes. This article is protected by copyright. All rights reserved.
No preview · Article · Jan 2016 · Clinical and Experimental Pharmacology and Physiology
[Show abstract][Hide abstract] ABSTRACT: Importance
The association between obesity and diabetic retinopathy (DR) is equivocal, possibly owing to the strong interrelation between generalized and abdominal obesity leading to a mutually confounding effect. To our knowledge, no study in Asia has investigated the independent associations of these 2 parameters with DR to date.Objective
To investigate the associations of generalized (defined by body mass index [BMI], calculated as weight in kilograms divided by height in meters squared) and abdominal obesity (assessed by waist to hip ratio [WHR]) with DR in a clinical sample of Asian patients with type 2 diabetes mellitus.Design, Setting, and Participants
This cross-sectional clinic-based study was conducted at the Singapore National Eye Centre, a tertiary eye care institution in Singapore, from December 2010 to September 2013. We recruited 498 patients with diabetes. After exclusion of participants with ungradable retinal images and type 1 diabetes, 420 patients (mean [SD] age, 57.8 [7.5] years; 32.1% women) were included in the analyses.Exposures
Body mass index and WHR as waist/hip circumference (in centimeters).Main Outcomes and Measures
The presence and severity of DR were graded from retinal images using the modified Airlie House Classification into none (n = 189), mild-moderate (Early Treatment Diabetic Retinopathy Study scale score, 20-41; n = 125), and severe DR (Early Treatment Diabetic Retinopathy Study scale score ≥53; n = 118). The associations of BMI and WHR with DR were assessed using multinomial logistic regression models adjusting for age, sex, traditional risk factors, and mutually for BMI and WHR.Results
Among the total of 420 patients, the median (interquartile range) for BMI and WHR were 25.7 (5.7) and 0.94 (0.08), respectively. In multivariable models, BMI was inversely associated with mild-moderate and severe DR (odds ratio [OR], 0.90 [95% CI, 0.84-0.97] and OR, 0.92 [95% CI, 0.85-0.99] per 1-unit increase, respectively), while WHR was positively associated with mild-moderate and severe DR (OR, 3.49 [95% CI, 1.50-8.10] and OR, 2.68 [95% CI, 1.28-5.62] per 0.1-unit increase, respectively) in women (P for interaction = .006). No sex-specific associations were found between BMI and DR (P for interaction >.10).Conclusions and Relevance
In Asian patients with type 2 diabetes, a higher BMI appeared to confer a protective effect on DR, while higher WHR was associated with the presence and severity of DR in women. Our results may inform future clinical trials to determine whether WHR is a more clinically relevant risk marker than BMI for individuals with type 2 diabetes.
No preview · Article · Dec 2015 · Jama Ophthalmology
[Show abstract][Hide abstract] ABSTRACT: Objectives: The purpose of this study were (i) to assess the knowledge, attitudes and practice (KAP) and impact of socioeconomic factors upon the prevalence of pre-diabetes and diabetes (ii) compute a diabetes risk score and (iii) estimate the undiagnosed prevalence of hypertension amongst a large adult population in rural Bangladesh. Methods/design: A sample of 3104 adults aged ≥30 years were interviewed from a cluster sample of 18 villages in the Banshgram Union of the Narail District, Bangladesh. Each participant was interviewed using a semi-structured questionnaire that assessed participant knowledge, attitudes and practice (KAP) regarding diabetes, its risk factors, complications and management. Data on demographic details, education, socioeconomic status, medical history, dietary and lifestyle behavior was obtained. Fasting capillary glucose, blood pressure, presenting vision and anthropometric parameters were measured. Participants were stratified into those without diabetes, pre-diabetes, and diagnosed diabetes (known and newly diagnosed). The association of KAP components and other risk factors with diabetes status was assessed. Logistic regression analysis allowed for the development of a non-invasive risk-stratification tool to be developed and implemented for the rural Bangladeshi community. Multinomial logistic regression was applied to report the associations of risk factors with the severity of hypertension. Results and discussion: In Banshgram, over 95% people had not undergone any previous diabetes screening. Baseline demographics estimated the prevalence of diabetes in the sample was 3.2% (n=99). 47% of participants had no formal education. Whilst there is literature on the prevalence of diabetes in urban and semi-urban Bangladesh there is a paucity of evidence examining the impact of KAP of diabetes amongst the general community. We believe that the BPDES has developed a methodology to provide new evidence to guide health policy and targeted population-based interventions in these rural areas.Bangladesh Journal of Medical Science Vol.14(4) 2015 p.367-375
Full-text · Article · Dec 2015 · Bangladesh Journal of Medical Science
[Show abstract][Hide abstract] ABSTRACT: Objective To determine the prevalence and risk factors of undiagnosed diabetic retinopathy (DR), in particular vision-threatening DR (VTDR) in a multiethnic Asian cohort. Design A population-based survey of 3353 Chinese, 3280 Malays and 3400 Indians (73.6% response) aged 40-80 years residing in Singapore. Diabetes mellitus (DM) was defined as random glucose 11.1 mmol/L, use of diabetic medication or a previous physician diagnosis. DR severity was graded from retinal photographs following the modified Airlie House classification. VTDR was defined as the presence of severe non-proliferative DR (NPDR), proliferative DR (PDR) or clinically significant macular oedema (CSMO), using the Eye Diseases Prevalence Research Group definition. Participants were deemed undiagnosed if they reported no prior physician diagnosis in structured interviews, in those with the condition. Results Of 10 033 participants, 2376 had DM (23.7%), of which 805 (33.9%) had DR. Among 2376 with DM, 11.1% (n=263) were undiagnosed. Among 805 with DR, 671 (83.3%) were undiagnosed. Among 212 with VTDR, 59 (27.3%) were undiagnosed. In multivariate models, factors associated with undiagnosed VTDR were higher lowdensity lipoprotein (LDL) cholesterol (OR=1.53, 95% CI 0.99 to 2.35, p=0.05) and absence of visual impairment or blindness in any eye in terms of best-corrected vision OR=3.00, 95% CI 1.47 to 6.11, p=0.003). Conclusions In this community, a quarter with VTDR is undiagnosed, and 8 in 10 with any DR are undiagnosed, compared with only 1 in 10 with DM undiagnosed. These findings suggest that screening for diabetes is successful, while screening for DR is currently inadequate in our population. Public health strategies to aid early diagnosis of DR in Singapore are urgently warranted to reduce blindness due to diabetes.
[Show abstract][Hide abstract] ABSTRACT: Background:
Singapore's population, as that of many other countries, is aging; this is likely to lead to an increase in eye diseases and the demand for eye care. Since ophthalmologist training is long and expensive, early planning is essential. This paper forecasts workforce and training requirements for Singapore up to the year 2040 under several plausible future scenarios.
The Singapore Eye Care Workforce Model was created as a continuous time compartment model with explicit workforce stocks using system dynamics. The model has three modules: prevalence of eye disease, demand, and workforce requirements. The model is used to simulate the prevalence of eye diseases, patient visits, and workforce requirements for the public sector under different scenarios in order to determine training requirements.
Four scenarios were constructed. Under the baseline business-as-usual scenario, the required number of ophthalmologists is projected to increase by 117% from 2015 to 2040. Under the current policy scenario (assuming an increase of service uptake due to increased awareness, availability, and accessibility of eye care services), the increase will be 175%, while under the new model of care scenario (considering the additional effect of providing some services by non-ophthalmologists) the increase will only be 150%. The moderated workload scenario (assuming in addition a reduction of the clinical workload) projects an increase in the required number of ophthalmologists of 192% by 2040. Considering the uncertainties in the projected demand for eye care services, under the business-as-usual scenario, a residency intake of 8-22 residents per year is required, 17-21 under the current policy scenario, 14-18 under the new model of care scenario, and, under the moderated workload scenario, an intake of 18-23 residents per year is required.
The results show that under all scenarios considered, Singapore's aging and growing population will result in an almost doubling of the number of Singaporeans with eye conditions, a significant increase in public sector eye care demand and, consequently, a greater requirement for ophthalmologists.
Full-text · Article · Nov 2015 · Human Resources for Health
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To study willingness to pay for cataract surgery and surgical service provided by a senior cataract surgeon in urban Southern China.
This study was a cross-sectional willingness-to-pay (WTP) interview using bidding formats. Two-hundred eleven persons with presenting visual impairment in either eye due to cataract were enrolled at a tertiary eye hospital. Participants underwent a comprehensive eye examination and a WTP interview for both surgery and service provided by a senior surgeon. Demographic information, socioeconomic status and clinical data were recorded.
Among 211 (98% response rate) persons completing the interview, 53.6% were women and 80.6% were retired. About 72.2% had a monthly income lower than 1000 renminbi (US $161). A total of 189 (89.6%) were willing to pay for cataract and the median amount of WTP was 6000 renminbi (US$968). And 102 (50.7%) were willing to pay additional fees for surgery performed by a senior surgeon, and the median amount of WTP was 500 renminbi (US$81). In regression models adjusting for age and gender, persons with preexisting eye diseases other than cataract, were more likely to pay for cataract surgery and service provided by a senior surgeon (P = 0.04 for both).
In urban China, cataract patients, especially those with preexisting eye conditions, are willing to pay additional fees for a senior surgeon. Moving to a system where the price of cataract surgery is proportional to the consultant' skill and expertise is possible and may have a potential impact on waiting list and quality of eye care. Further studies are needed to examine the impact of such pricing system on attitudes and choices of cataract patients.
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To investigate the independent relationship of individual- and area-level socio-economic status (SES) with the presence and severity of visual impairment (VI) in an Asian population.
Cross-sectional data from 9993 Chinese, Malay and Indian adults aged 40-80 years who participated in the Singapore Epidemiology of eye Diseases (2004-2011) in Singapore. Based on the presenting visual acuity (PVA) in the better-seeing eye, VI was categorized into normal vision (logMAR≤0.30), low vision (logMAR>0.30<1.00), and blindness (logMAR≥1.00). Any VI was defined as low vision/blindness in the PVA of better-seeing eye. Individual-level low-SES was defined as a composite of primary-level education, monthly income<2000 SGD and residing in 1 or 2-room public apartment. An area-level SES was assessed using a socio-economic disadvantage index (SEDI), created using 12 variables from the 2010 Singapore census. A high SEDI score indicates a relatively poor SES. Associations between SES measures and presence and severity of VI were examined using multi-level, mixed-effects logistic and multinomial regression models.
The age-adjusted prevalence of any VI was 19.62% (low vision = 19%, blindness = 0.62%). Both individual- and area-level SES were positively associated with any VI and low vision after adjusting for confounders. The odds ratio (95% confidence interval) of any VI was 2.11(1.88-2.37) for low-SES and 1.07(1.02-1.13) per 1 standard deviation increase in SEDI. When stratified by unilateral/bilateral categories, while low SES showed significant associations with all categories, SEDI showed a significant association with bilateral low vision only. The association between low SES and any VI remained significant among all age, gender and ethnic sub-groups. Although a consistent positive association was observed between area-level SEDI and any VI, the associations were significant among participants aged 40-65 years and male.
In this community-based sample of Asian adults, both individual- and area-level SES were independently associated with the presence and severity of VI.
[Show abstract][Hide abstract] ABSTRACT: Purpose: To determine the association of visual field (VF) progression
with medication persistence in a cohort on glaucoma
Patients and Methods: Pharmacy records were examined over 3
years for patients started on glaucoma monotherapy. A patient was
persistent if a prescription was refilled for the same medication
<90 days after the previous prescription had lapsed; otherwise was
nonpersistent. Only patients with >5 reliable VFs within 1-year
pretherapy and 6-year posttherapy were included. Progression was
analyzed with pointwise linear regression and defined using 2 criteria:
(A) Z2 adjacent progressing points (slope P<0.01) in 1
hemifield; and (B) Z3 progressing points (slope P<0.01). The
mean number and mean slope of progressing points and the mean
global slopes were determined.
Results: Of 1206 patient eyes (131 persistent, 1075 nonpersistent),
941 were excluded leaving 175 (47 persistent and 128 nonpersistent)
for analysis. The mean follow-up durations were 59.3±10.9 and
58.2±9.7 months (P=0.07) for persistent and nonpersistent eyes,
respectively. Overall, 2/47 (4.3%) and 10/128 (7.8%) eyes progressed
among persistent and nonpersistent patients, respectively
(P=0.52) using criterion A and 1/47 (2.1%) and 12/128 (9.4%;
P=0.19) eyes using criterion B. Mean number of progressing
points (0.3±0.9 vs. 0.7±1.8; P=0.17), mean slope of progressing
points (�2.2±1.1 vs. �2.8±1.3 dB/y; P=0.27), and mean
global slope (0.7±0.5 vs. �0.1±0.8 dB/y; P=0.07) were similar
for persistent and nonpersistent patients, respectively.
Conclusion: There were small but appreciable differences in VF
progression rates between persistent and nonpersistent patient eyes
on glaucoma drops, but differences were not significant.
Full-text · Article · Nov 2015 · Journal of Glaucoma
[Show abstract][Hide abstract] ABSTRACT: We investigated the relationship of visual impairment (VI) and age-related eye diseases with mortality in a prospective, population-based cohort study of 3,280 Malay adults aged 40–80 years between 2004–2006. Participants underwent a full ophthalmic examination and standardized lens and fundus photographic grading. Visual acuity was measured using logMAR chart. VI was defined as presenting (PVA) and best-corrected (BCVA) visual acuity worse than 0.30 logMAR in the better-seeing eye. Participants were linked with mortality records until 2012. During follow-up (median 7.24 years), 398 (12.2%) persons died. In Cox proportional-hazards models adjusting for relevant factors, participants with VI (PVA) had higher all-cause mortality (hazard ratio[HR], 1.57; 95% confidence interval[CI], 1.25–1.96) and cardiovascular (CVD) mortality (HR 1.75; 95% CI, 1.24–2.49) than participants without. Diabetic retinopathy (DR) was associated with increased all-cause (HR 1.70; 95% CI, 1.25–2.36) and CVD mortality (HR 1.57; 95% CI, 1.05–2.43). Retinal vein occlusion (RVO) was associated with increased CVD mortality (HR 3.14; 95% CI, 1.26–7.73). No significant associations were observed between cataract, glaucoma and age-related macular degeneration with mortality. We conclude that persons with VI were more likely to die than persons without. DR and RVO are markers of CVD mortality.
[Show abstract][Hide abstract] ABSTRACT: Purpose To compare vision-related quality of life (VRQoL) scores and clinical outcomes between small-incision lenticule extraction and laser in situ keratomileusis (LASIK). Setting Singapore National Eye Centre, Singapore. Design Prospective study. Methods Patients had small-incision lenticule extraction using the Visumax 500 kHz femtosecond laser; or LASIK excimer ablation with the Wavelight Allegretto 400 Hz laser. Primary outcomes were 3-month predictability, efficacy, and safety. Secondary outcomes were intraoperative experience, visual symptoms, and VRQoL (validated Quality of Life Impact of Refractive Correction [QIRC] questionnaire) in 25 a subgroup of patients in each group. Following Rasch analysis, "Functional" and "Emotional," QIRC dimensions were analysed separately. Results At 3 months, predictability (82.5% versus 85.3%, ±0.5 diopters attempted correction, P =.453), safety index (1.13 ± 0.19 [SD] versus 1.07 ± 0.16, P =.158), and efficacy index (0.91 ± 0.21 versus 0.97 ± 0.19; P =.002) were found when comparing small-incision lenticule extraction (172 eyes) and LASIK (matched 688 eyes). Intraoperative experience between groups was not statistically different; visual fluctuations (P =.020) and episodes of visual blurring (P =.008) were greater after small-incision lenticule extraction than after LASIK at 1 month but not at 3 months. There was no difference in "functional" (66.7 ± 15.7 versus 55.3 ± 22.2, P =.064) and "emotional" (42.7 ± 23.2 versus 37.9 ± 23.8, P =.394) QIRC dimensions between the 2 groups (25 patients in each group) at 3 months. Conclusion The study, 3-month predictability, safety, and VRQL scores were not statistically different between small-incision lenticule extraction and LASIK. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.
No preview · Article · Oct 2015 · Journal of Cataract and Refractive Surgery
[Show abstract][Hide abstract] ABSTRACT: Purpose:
We investigated whether the Chinese impact of vision impairment (IVI) questionnaire is valid to generate reliable person estimates in a population-based sample.
VRQoL was measured using the 32-item Chinese version of the IVI questionnaire in the Singapore Chinese Eye Study (2009-2011), a population-based study of the prevalence and risk factors for VI and eye diseases in Chinese Singaporeans. Rasch analysis was used to assess the Chinese IVI's response category functioning, precision, unidimensionality, targeting and differential item functioning. The ability of the Chinese IVI to discriminate participants along the spectrum of VI demonstrated criterion validity.
Of the 3353 participants, 27.2 % (n = 912) had VI (presenting visual acuity <6/12, better eye). Response categories were collapsed from six to four to resolve disordered thresholds. The Chinese IVI initially demonstrated multidimensionality and was split into three scales: 'Reading and Accessing Information'; 'Mobility and Independence'; and 'Emotional Well-being'. All three scales were unidimensional and demonstrated excellent range-based precision (all reliability coefficients 0.97), following removal of three misfitting items. Mean person measures decreased with worsening VI (e.g. Reading: none (7.50 logits); mild (6.99 logits); moderate (6.44 logits); and severe (3.01 logits) VI; p < 0.001).
A three-dimensional 29-item Chinese IVI is a valid tool to assess the impact of VI on VRQoL in a large population-based sample, comprising over a quarter of participants with VI. The 28-item English IVI is also likely to be valid for use in population-based studies; however, this must be demonstrated empirically in future studies.
Full-text · Article · Sep 2015 · Quality of Life Research
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To describe the relationship between peripapillary choroidal thickness and retinal nerve fiber layer (RNFL) thickness in a population-based sample of non-glaucomatous eyes.
Population-based, cross-sectional study.
478 non-glaucomatous subjects aged over 40 years were recruited from the Singapore Malay Eye Study (SiMES-2). All participants underwent a detailed ophthalmic examination, including Cirrus and Spectralis optical coherence tomography (OCT) for the measurements of RNFL thickness and peripapillary choroidal thickness respectively. Associations between peripapillary choroidal thickness and RNFL thickness were assessed using linear regression models with generalized estimating equations.
Of the 424 included subjects (843 non-glaucomatous eyes), 39% were men, and the mean (SD) age was 66.7 (10.5) years. The mean peripapillary choroidal thickness was 135.59 ± 56.74 μm and the mean RNFL thickness was 92.92 ± 11.41 μm. In terms of distribution profile, peripapillary choroid was thickest (150.04 ± 59.72 μm) at superior and thinnest (110.71 ± 51.61 μm) at inferior quadrant, whereas RNFL was thickest (118.60 ± 19.83 μm) at inferior and thinnest (67.36 ± 11.36 μm) at temporal quadrant. We found that thinner peripapillary choroidal thickness was independently associated with thinner RNFL thickness globally (regression coefficient [β] = - 1.334 μm for per SD decrease in PPCT, p = 0.003), and in the inferior (β = - 2.565, p = 0.001) and superior (β = - 2.340, p = 0.001) quadrants even after adjusting for potential confounders.
Thinner peripapillary choroid was independently associated with thinner RNFL globally and in the inferior and superior regions. This structure-structure relationship may need further exploration in glaucomatous eyes to apply in clinical settings.
No preview · Article · Sep 2015 · American Journal of Ophthalmology
[Show abstract][Hide abstract] ABSTRACT: Background:
Glaucoma is the leading cause of irreversible blindness in the world. Estimated to affect 60 million people worldwide, this figure is expected to rise to 80 million by 2020. Untreated, glaucoma leads to visual decay and eventually to blindness, and can significantly reduce quality of life. First-line treatment in patients with primary open-angle glaucoma and exfoliative glaucoma is topical medical therapy with ocular hypotensives as eye drops. However, eye drops have several disadvantages including cost, possible local and systemic side effects, and adherence and perseverance issues. Randomised controlled trials have demonstrated that selective laser trabeculoplasty is equally as effective in lowering intraocular pressure as eye drops. However, the impact of these two treatment modalities from the patient and economic perspectives has not been adequately determined. Thus, it remains unclear whether topical medical therapy or selective laser trabeculoplasty should be recommended as first-line treatment for glaucoma.
This protocol describes an international, multi-centre, randomised controlled trial to determine the optimum first-line therapy for people with primary open-angle glaucoma and exfoliative glaucoma. This study will compare the effect of selective laser trabeculoplasty and topical medication with respect to patients' generic and glaucoma-specific quality of life. The trial will also provide a detailed cost-effectiveness analysis and compare the clinical effectiveness with respect to the degree of intraocular pressure lowering and rates of treatment failure. Research coordinators in each centre will identify and recruit previously untreated patients with primary open-angle glaucoma and exfoliative glaucoma. Those who meet the eligibility criteria will be invited to enter a randomised controlled trial with either selective laser trabeculoplasty or topical ocular hypotensive therapy, according to a stepped regimen. Outcome assessment will be measured at 6 weeks and at 6, 12, and 24 months post-treatment. Regular clinic follow-ups will continue as clinically indicated between study outcome visits.
The Glaucoma Initial Treatment Study is the first multi-centred RCT to determine the optimum first-line therapy for people with glaucoma. Our trial will have an unprecedented capacity to meaningfully transform the treatment and management of glaucoma in Australia and overseas.
ACTRN12611000720910 ; Date registered: 11 July 2011.
[Show abstract][Hide abstract] ABSTRACT: Aim:
To explore the association between alcohol consumption and the severity of diabetic retinopathy (DR).
In this cross-sectional study, patients with type 2 diabetes answered questions on consumption of low and full-strength beer, white wine/champagne, red wine, fortified wines, and spirits. Never, moderate and high consumption of each alcoholic beverage, and overall alcoholic beverage consumption, were defined as <1, 1-14 and >14 standard drinks/week, respectively. DR was categorized into none; non vision-threatening DR (VTDR) and VTDR. Multivariable logistic regression determined the associations between alcohol consumption and DR.
Of the 395 participants (mean age±SD [standard deviation] 65.9±10.4years; males=253), 188 (47.6%) consumed alcohol and 235 (59.5%) had any DR. Compared to no alcohol consumption, moderate alcohol consumption (overall) was significantly associated with reduced odds of any DR (OR=0.47, 95% CI [confidence interval] 0.26-0.85). Moderate consumption of white wine/champagne or fortified wine was also associated with reduced odds of any DR (OR=0.48, 95% CI 0.25-0.91, and OR=0.15, 95% CI 0.04-0.62, respectively). Similar results were observed for non-VTDR and VTDR.
The amount and type of alcohol are associated with risk of DR in patients with type 2 diabetes. A longitudinal study is needed to assess the protective effect of alcohol consumption and DR.
Full-text · Article · Sep 2015 · Journal of diabetes and its complications