Metabolic syndrome and eye diseases

Metabolic syndrome is becoming a worldwide medical and public health challenge as it has been seen increasing in prevalence over the years. Age-related eye diseases, the leading cause of blindness globally and visual impairment in developed countries, are also on the rise due to aging of the population. Many of the individual components of the metabolic syndrome have been shown to be associated with these eye diseases. However, the association of metabolic syndrome with eye diseases is not clear. In this review, we reviewed the evidence for associations between metabolic syndrome and certain ocular diseases in populations. We also reviewed the association of individual metabolic syndrome components with ocular diseases due to a paucity of research in this area. Besides, we also summarised the current understanding of etiological mechanisms of how metabolic syndrome or the individual components lead to these ocular diseases. With increasing evidence of such associations, it may be important to identify patients who are at risk of developing metabolic syndrome as prompt treatment and intervention may potentially decrease the risk of developing certain ocular diseases.

Relationship of ocular and systemic factors to the visibility of choroidal-scleral interface using spectral domain optical coherence tomography

PURPOSE

To assess the visibility of the choroidal-scleral interface (CSI) from spectral domain optical coherence tomography (SD-OCT) and evaluate the ocular and systemic factors influencing the visibility of CSI in healthy eyes from population-based Malay sample.

METHODS

Participants were consecutively recruited from the population-based Singapore Malay Eye Study-2 (SiMES-2). SD-OCT images were obtained by Spectralis OCT with enhanced depth imaging (EDI) mode. Visibility of CSI was assessed by a grading system ranging from 0 to 2 scores. The reliability of choroidal thickness measurement in different grades of CSI visibility was assessed using intraclass correlation coefficient. Ordinal regression analyses were performed to evaluate a range of ocular and systemic factors influencing the visibility of CSI.

RESULTS

A total of 176 healthy eyes were analysed, and 59.1% of our subjects had well-defined CSI (score 2), 8.5% had poorly defined CSI (score 0), and 32.4% had CSI between well and poorly defined (score 1). The reliability of subfoveal choroidal thickness measurement decreased with each grade of CSI visibility score. Decreased axial length (AL) (estimate of ordinal regression [OR] = 0.465, p = 0.003), thicker retinal thickness (estimate of OR = -0.030, p = 0.004), younger age (estimate of OR = 0.045, p = 0.030) and diabetes (estimate of OR = -0.746, p = 0.004) were associated with lower CSI visibility score.

CONCLUSIONS

Only 60% of normal healthy eyes had well-defined CSI from SD-OCT images. Our data suggest that choroidal thickness measurements can be substantially affected by the visibility of CSI. The visibility of CSI varies with AL, retinal thickness, age and diabetes.

Increased Burden of Vision Impairment and Eye Diseases in Persons with Chronic Kidney Disease - A Population-Based Study

BACKGROUND

Chronic kidney disease (CKD) has been shown to be associated with diabetic retinopathy (DR) and age-related macular degeneration (AMD), leading causes of blindness in elderly adults in previous studies. However, the association of CKD with visual impairment (VI) is not clear. We aimed to examine the association of CKD with VI and other age-related ocular diseases in a population-based sample of Asian adults.

METHODS

We analyzed data from 10,033 adults aged 40-80 years who participated in the Singapore Epidemiology of Eye Diseases (SEED, 2004-11) Study. CKD was defined as an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m(2) from serum creatinine. VI was defined as best-corrected visual acuity < 20/40 in the better eye. Cataract, retinopathy, DR, glaucoma and AMD were assessed using standardized ocular examination, retinal photography and visual field assessments. The associations of CKD with VI and ocular conditions were examined using logistic regression models adjusted for age, sex, race, smoking, alcohol intake, education status, body mass index, systolic blood pressure, diabetes mellitus, cholesterol levels and cardiovascular disease.

FINDINGS

The prevalence of VI and ocular disease were significantly higher in participants with CKD (36.1% and 84.7%) than in those without (12.9% and 54.3%, both p < 0.001). In multivariable models, CKD was significantly associated with VI (odds ratio [95% confidence interval] = 1.34 [1.14-1.58]), any ocular disease (1.28 [1.03-1.61]), cataract (1.24 [1.01-1.52]), any retinopathy (1.77 [1.45-2.15]), and DR (1.94 [1.47-2.54]).

INTERPRETATION

The burden of VI and eye diseases is high among persons with CKD. Our findings suggest that it may be useful to screen for ocular disease and VI in persons with CKD.

Relationship Between Peripapillary Choroid and Retinal Nerve Fiber Layer Thickness in a Population-Based Sample of Nonglaucomatous Eyes

PURPOSE

To describe the relationship between peripapillary choroidal thickness and retinal nerve fiber layer (RNFL) thickness in a population-based sample of nonglaucomatous eyes.

DESIGN

Population-based, cross-sectional study.

METHODS

A total of 478 nonglaucomatous 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.

RESULTS

Of the 424 included subjects (843 nonglaucomatous eyes), 60.9% were women, and the mean (SD) age was 66.74 (10.44) 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 the superior and thinnest (110.71 ± 51.61 μm) at the inferior quadrant, whereas RNFL was thickest (118.60 ± 19.83 μm) at the inferior and thinnest (67.36 ± 11.36 μm) at the temporal quadrant. We found that thinner peripapillary choroidal thickness (PPCT) was independently associated with thinner RNFL thickness globally (regression coefficient [β] = -1.334 μm for per-SD decrease in PPCT, P = .003), and in the inferior (β = -2.565, P = .001) and superior (β = -2.340, P = .001) quadrants even after adjusting for potential confounders.

CONCLUSIONS

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 prior to its application in clinical settings.

Moderate consumption of white and fortified wine is associated with reduced odds of diabetic retinopathy

AIM

To explore the association between alcohol consumption and the severity of diabetic retinopathy (DR).

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

The Association of Estimated Glomerular Filtration Rate With Diabetic Retinopathy and Macular Edema

PURPOSE

Albuminuria, a marker of diabetic kidney disease, is closely associated with diabetic retinopathy (DR) and diabetic macular edema (DME). However, the relationship between estimated glomerular filtration rate (eGFR) with DR and DME remains unclear, particularly in type 2 diabetes. We investigated the association of eGFR with DR and DME in a sample of patients with type 2 diabetes.

METHODS

We included 263 Caucasian patients with type 2 diabetes aged ≥ 18 years who participated in a clinic-based cross-sectional study in Melbourne, Australia. Diabetic retinopathy (n = 140) and DME (n = 61) were assessed from retinal photographs graded using the modified Airlie House classification and further confirmed with optical coherence tomography. Estimated glomerular filtration rate, assessed using the CKD-EPI formula, was analyzed continuously (per SD change) and categorically (normal renal function ≥ 90; impaired renal function, 60-89, and chronic kidney disease [CKD] < 60 mL/min/1.73 m2).

RESULTS

When eGFR was analyzed categorically, impaired renal function and CKD were associated with the presence of DR when compared to normal renal function in multivariable models (odds ratio [OR] with 95% confidence interval [CI] of 2.97 [1.12-7.87] and 3.77 [1.28-11.10]), respectively. In DR severity analyses, CKD showed significant associations with moderate (5.83 [1.44-23.5], P-trend = 0.02) and severe DR (4.91 [1.26-19.0], P-trend = 0.04). These associations persisted when eGFR was analyzed continuously (P = 0.04). No significant associations were found between eGFR and DME.

CONCLUSIONS

Our results suggest that lower levels of eGFR were associated with the presence and severity of DR, but not with DME.

Genome-wide association study for sight-threatening diabetic retinopathy reveals association with genetic variation near the GRB2 gene

AIMS/HYPOTHESIS

Diabetic retinopathy is a serious complication of diabetes mellitus and can lead to blindness. A genetic component, in addition to traditional risk factors, has been well described although strong genetic factors have not yet been identified. Here, we aimed to identify novel genetic risk factors for sight-threatening diabetic retinopathy using a genome-wide association study.

METHODS

Retinopathy was assessed in white Australians with type 2 diabetes mellitus. Genome-wide association analysis was conducted for comparison of cases of sight-threatening diabetic retinopathy (n = 336) with diabetic controls with no retinopathy (n = 508). Top ranking single nucleotide polymorphisms were typed in a type 2 diabetes replication cohort, a type 1 diabetes cohort and an Indian type 2 cohort. A mouse model of proliferative retinopathy was used to assess differential expression of the nearby candidate gene GRB2 by immunohistochemistry and quantitative western blot.

RESULTS

The top ranked variant was rs3805931 with p = 2.66 × 10(-7), but no association was found in the replication cohort. Only rs9896052 (p = 6.55 × 10(-5)) was associated with sight-threatening diabetic retinopathy in both the type 2 (p = 0.035) and the type 1 (p = 0.041) replication cohorts, as well as in the Indian cohort (p = 0.016). The study-wide meta-analysis reached genome-wide significance (p = 4.15 × 10(-8)). The GRB2 gene is located downstream of this variant and a mouse model of retinopathy showed increased GRB2 expression in the retina.

CONCLUSIONS/INTERPRETATION

Genetic variation near GRB2 on chromosome 17q25.1 is associated with sight-threatening diabetic retinopathy. Several genes in this region are promising candidates and in particular GRB2 is upregulated during retinal stress and neovascularisation.

Comparing the effectiveness of selective laser trabeculoplasty with topical medication as initial treatment (the Glaucoma Initial Treatment Study): study protocol for a randomised controlled trial

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.

Methods/Design

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.

Discussion

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.

Trial registration

ACTRN12611000720910; Date registered: 11 July 2011

The Influence of Coping on Vision-Related Quality of Life in Patients With Low Vision: A Prospective Longitudinal Study

PURPOSE

To determine the longitudinal impact of specific coping strategies on vision-related quality of life (VRQoL) in patients with low vision.

METHODS

This was a single-group, longitudinal study utilizing telephone-administered interviews conducted at baseline and at 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. Vision-related quality of life 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.

RESULTS

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.

CONCLUSIONS

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.

Neuronal activity-dependent regulation of retinal blood flow

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.

Common Sequence Variation in the VEGFC Gene Is Associated with Diabetic Retinopathy and Diabetic Macular Edema

PURPOSE

To investigate associations between single nucleotide polymorphisms (SNPs) in the VEGFC gene and the development of diabetic retinopathy (DR) in white patients with type 1 diabetes mellitus (T1DM) or type 2 diabetes mellitus (T2DM).

DESIGN

Cross-sectional, case control study.

PARTICIPANTS

White patients with T1DM or T2DM (n = 2899) were recruited from ophthalmology and endocrine clinics in Australia and the United Kingdom. Patients with T2DM were required to have diabetes mellitus (DM) for at least 5 years and be receiving oral hypoglycemic treatment or insulin.

METHODS

Participants were categorized according to their worst-ever DR grading, as having "no DR" (no history of nonproliferative DR [NPDR], proliferative DR [PDR], or diabetic macular edema [DME]) or "any DR" (further subclassified as NPDR or PDR, without or with DME). Clinical characteristics, glycemic control (hemoglobin A1c [HbA1c]), and presence of diabetic complications were determined at recruitment. Genotyping was performed for 13 VEGFC tag SNPs.

MAIN OUTCOME MEASURES

Odds ratios (ORs) were determined for associations with DR of VEGFC tag SNPs, individually and within haplotypes. Logistic regression was used to adjust for clinical covariates, including DM type, age, sex, DM duration, hypertension, nephropathy, HbA1c, and smoking.

RESULTS

Participants with DM but "no DR" (n = 980) were compared with 1919 participants with DM and "any DR." Three VEGFC SNPs were associated with DR after logistic regression: rs17697419 (P = 0.001; OR, 0.67; confidence interval [CI], 0.52-0.85), rs17697515 (P = 0.001; OR, 0.62; CI, 0.47-0.81), and rs2333526 (P = 0.005; OR, 0.69; CI, 0.54-0.90). rs17697515 Was also specifically associated with DME in those with T2DM (P = 0.004; OR, 0.53; CI, 0.35-0.82). Haplotype analysis revealed 2 significantly associated haplotypes, both protective against DR development.

CONCLUSIONS

Significant associations were found between VEGFC tag SNPs (individually and within haplotypes) and the presence of any DR or DME in white participants with T1DM and T2DM.

Prevalence and determinants of undiagnosed diabetic retinopathy and vision-threatening retinopathy in a multiethnic Asian cohort: the Singapore Epidemiology of Eye Diseases (SEED) study

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 low-density 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.

Do problem-solving interventions improve psychosocial outcomes in vision impaired adults: a systematic review and meta-analysis

OBJECTIVE

To evaluate the effectiveness of problem-solving interventions on psychosocial outcomes in vision impaired adults.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

PRACTICE IMPLICATIONS

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.

A genetic variant regulating miR-126 is associated with sight threatening diabetic retinopathy

BACKGROUND

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.

MATERIALS AND METHODS

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.

RESULTS

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).

CONCLUSION

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.

A randomised controlled trial of a self-management programme for low vision implemented in low vision rehabilitation services

OBJECTIVE

To investigate the effectiveness of a low vision self-management programme (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 8-week group programme 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).

RESULTS

At 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 programme on QoL for older adults accessing low vision services.

PRACTICE IMPLICATIONS

When implementing self-management programmes in low vision rehabilitation settings, issues of client interest, divergence of need, programme accessibility and fidelity of intervention delivery need to be addressed.

Body mass index and retinopathy in Asian populations with diabetes mellitus

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.

Distribution and determinants of choroidal thickness and volume using automated segmentation software in a population-based study

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 μm), followed by 3 mm temporal (207.65 ± 80.98 μm), and was thinnest at 3 mm nasal (142.44 ± 79.19 μm) 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.

Diagnosis of diabetes mellitus using HbA1c in Asians: relationship between HbA1c and retinopathy in a multiethnic Asian population

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 y: Chinese, 5834; Malays, 3596; and Indians, 3740).

MAIN OUTCOME

Moderate retinopathy was assessed from digital retinal photographs and defined as a level >43 using the Early Treatment Diabetic Retinopathy Study (ETDRS) scale. Sensitivity, specificity, positive and negative predictive values, and the area under the receiver operating characteristic curve 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 < .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 subjects compared to Indians and Malays (75.8 vs 86.0 and 85.3%), but specificity (89.7 vs 71.9 and 76.3%) was higher; however, positive predictive value and negative predictive value were similar among Chinese, Indians, and Malays (10.5, 12.3, 12.4%; and 99.6, 99.1, 99.2%, respectively). 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 interethnic variation in the relationship of HbA1c and retinopathy, a cut-point of 6.5% performs reasonably well in the three major Asian ethnic groups.

Peripapillary choroidal thickness assessed using automated choroidal segmentation software in an Asian population

AIMS

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.

METHODS

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).

RESULTS

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.

CONCLUSIONS

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.

Help seeking among vision-impaired adults referred to their GP for depressive symptoms: patient characteristics and outcomes associated with referral uptake

Adults with vision impairment commonly experience depression; however, depression often remains undetected and therefore untreated in this group. Using a prospective longitudinal design, the aim of this study was to determine the rate of uptake for a referral to a general practitioner (GP), in vision-impaired adults, who were screened for depression in low vision rehabilitation and eye-care settings. Fifty-seven vision-impaired adults (aged ≥18 years) were recruited from low vision rehabilitation centres across Australia and the Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, between June 2010 and May 2012. Participants screened positive for depressive symptoms and were referred to their GP for follow up. Telephone assessments took place at baseline, 3 and 6 months to determine uptake of a GP referral and changes in depressive symptoms over 6 months. Forty-six per cent of participants followed through with the GP referral. A desire for emotional support and stigma towards seeking support from a psychologist were significantly associated with uptake (both P < 0.05). GPs were more likely to recommend anti-depressant medication compared with a psychologist consultation (69% v. 54%) and patients themselves were more likely to take anti-depressant medication (94% v. 14% who saw a psychologist). Depressive symptoms decreased significantly over 6 months for those who followed through with a GP referral (baseline M = 10.04, s.d. = 5.76 v. 6-months M = 6.20, s.d. = 3.38; z = –2.26, P = 0.02) but not for those who did not use the GP referral (z = –1.92, P = 0.55). This method of referral to a GP following depression screening may provide an effective pathway to detect and manage depression in vision-impaired adults.

Prevalence and risk factors for retinopathy in persons without diabetes: the Singapore Indian Eye Study

PURPOSE

To describe prevalence and risk factors for retinopathy in an Asian Indian population without diabetes.

METHODS

A population-based cross-sectional study of 3400 Indians aged 40-80 years residing in Singapore was conducted. Retinopathy was assessed from retinal photographs by trained graders using modified Airlie House Classification System. Risk factors were assessed from standardized interviews, clinical examinations and laboratory investigations. Diabetes mellitus was defined as glycosylated haemoglobin ≥6.5%, use of diabetic medication or physician diagnosis of diabetes.

RESULTS

Among the 1900 individuals without diabetes, mean HbA1c was 5.7% and mean systolic blood pressure was 132.4 mmHg. Age-standardized prevalence of retinopathy was 5.05% (n = 98; 95% confidence interval [CI], 4.07-6.21), with no significant difference in retinopathy prevalence between males (6.15%) and females (4.13%). Among non-diabetic persons with retinopathy, 96.9% (n = 95) had signs of minimal-to-mild retinopathy while 3.06% (n = 3) had moderate-to-severe retinopathy. After adjusting for multiple covariables, retinopathy signs were associated with higher levels of HbA1c (odds ratio [OR], 2.4; 95% CI, 1.3-4.5; per% increase), systolic blood pressure (OR, 1.02; 95% CI, 1.01-1.03; per mmHg increase) and serum creatinine (OR, 1.005; 95% CI, 1.002-1.009; per mm increase), but not C-reactive protein, cigarette smoking or lipid levels.

CONCLUSION

One in 20 Asian Indian persons without diabetes had retinopathy signs. Risk factors for these signs include higher glycosylated haemoglobin, systolic blood pressure and serum creatinine.

Is chronic kidney disease associated with diabetic retinopathy in Asian adults?

BACKGROUND

Diabetic nephropathy (DN) is commonly associated with diabetic retinopathy (DR). Few studies have demonstrated that chronic kidney disease (CKD) is associated with DR. However, it is not clear if CKD in the absence of albuminuria is associated with DR.

METHODS

We included 301 participants with diabetes (Chinese, Malay and Indian ethnicity aged ≥24 years who participated in the Singapore Prospective Study Program (2003-2007). Retinal photographs taken from both eyes were graded for DR using the modified Airlie House Classification. We examined the association of CKD defined by low estimated glomerular filtration rate (eGFR) (<60 mL/min per 1.73 m(2) , n = 54), and albuminuria (urinary albumin-to-creatinine ratio ≥30, n = 116) with any-DR (n = 99) in logistic regression models. We replicated this analysis in another independent population-based sample of Malay adults (n = 265) with similar methodology in Singapore.

RESULTS

41% of those with low-eGFR had normoalbuminuria. In separate models, while albuminuria was significantly associated with any-DR, low-eGFR was not significantly associated with any-DR. In a model combining both markers, compared to the referent group (normal-eGFR+normoalbuminuria), the odds ratio (OR) (95% confidence interval [CI]) of any-DR were: 2.33 (1.27-4.27) for normal-eGFR+albuminuria, 1.38 (0.49-3.91) for low-eGFR + normoalbuminuria, and 2.64 (1.05-6.63) for low-eGFR+albuminuria. Similar findings for any-DR were observed in the replication cohort of Malay persons (3.56 [1.49-8.54] for normal-eGFR+albuminuria, 1.69 (0.52-5.55) for low-eGFR+normoalbuminuria, 4.34 [1.68-11.24] for low-eGFR+albuminuria.

CONCLUSION

We demonstrated that CKD is associated with DR only in the presence of albuminuria suggesting that CKD is more likely related to diabetes in the presence of albuminuria.

Flicker light-induced retinal vasodilation is unaffected by inhibition of epoxyeicosatrienoic acids and prostaglandins in humans

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 nonsmokers 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 hour 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-minute intervals for 2 hours. Within-subject differences were assessed by ANOVA and Dunnett-adjusted pairwise comparisons with significance taken at P < 0.05.

RESULTS

In crossover study participants, mean (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% CI) 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 hours (P < 0.001).

CONCLUSIONS

Epoxyeicosatrienoic acids and prostaglandins 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.

Health literacy, computer skills and quality of patient-physician communication in Chinese patients with cataract

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.

The Prevalence and Determinants of Desire for and Use of Psychological Support in Patients With Low Vision

PURPOSE

The objective of this study was to identify the prevalence and determinants of desire for and use of psychological support in patients with low vision.

DESIGN

The study was cross-sectional, utilizing telephone-administered interviews.

METHODS

Patients were recruited from Vision Australia and the Royal Victorian Eye and Ear Hospital with visual acuity of less than 6/12 in the better eye. Measures were the 9-item Patient Health Questionnaire, Stigma Scale for Receiving Psychological Help, Brief Illness Perception Questionnaire, and Impact of Vision Impairment Questionnaire.

RESULTS

Of the total 161 participants (mean ± SD, 69.94 ± 15.76 years; 67% female), 63% desired psychological support, but only 20% reported ever receiving this. Higher levels of depressive symptoms and poorer coping in relation to vision impairment were significantly associated with desire for psychological support. Younger age, experience/s of depression, and beliefs about depression and its treatment were associated with use of professional support.

CONCLUSIONS

Many patients with low vision desired psychological support but were not receiving this, suggesting barriers to receipt of care. This highlights the need for early screening of emotional difficulties, depression education, and easy access to psychological support within low vision services.

Associations of retinal oximetry in persons with diabetes

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.

DESIGN

Clinic-based cross-sectional study.

PARTICIPANTS

Fifty-eight 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 (Imedos UG, Jena, Germany) 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 [DR]; glycated haemoglobin; triglyceride; total cholesterol; finger SO₂ and ocular perfusion pressure) with retinal oximetry measures.

MAIN OUTCOME MEASURE

Arteriolar SO₂, venular SO₂ and the arterio-venous (A-V) difference.

RESULTS

Of the candidate factors assessed, only the presence of DR was significantly associated with increased venular SO₂ and decreased A-V difference in unadjusted analyses. In models adjusting for age and gender and significant variables from unadjusted analyses, compared with no DR, the presence of DR was significantly associated with greater retinal venular SO₂ 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 DR were associated with increased venular SO₂ and decreased A-V difference compared with eyes without DR, suggesting an altered metabolic state in DR.

Depression screening among older adults attending low-vision rehabilitation and eye-care services: Characteristics of those who screen positive and client acceptability of screening

AIM

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.

METHODS

One-hundred and twenty-four older adults (mean = 77.02 years, SD = 9.12) attending low-vision rehabilitation and eye-care services across Australia were screened for depression and invited to complete a telephone-administered questionnaire to determine characteristics associated with depressive symptoms and client acceptability of screening in these settings.

RESULTS

Thirty-seven per cent (n = 46/124) of participants screened positive for depressive symptoms, and the majority considered the new depression screening method to be a 'good idea' in vision services (85%). Severe vision loss (<6/60 in the better eye) was associated with an increased odds of screening positive for depressive symptoms (odds ratio 2.37; 95% confidence interval 1.08-6.70) even after adjusting for potential confounders. Participants who screened positive had a preference for 'talking' therapy or a combination of medication and 'talking therapy' delivered within their own home (73%) or via telephone (67%).

CONCLUSION

The PHQ-2 appears to be an acceptable method for depression screening in eye-care settings among older adults. Targeted interventions that incorporate home-based or telephone delivered therapy sessions may improve outcomes for depression in this group.

Near Vision Impairment Is Associated With Cognitive Impairment in Type 2 Diabetes

PURPOSE

The objective of this study was to assess the relationship between vision and cognitive impairment in patients with type 2 diabetes mellitus (DM) who are at risk of both conditions.

DESIGN

This was a cross-sectional study.

METHODS

Persons with type 2 DM underwent a comprehensive clinical examination. Distance and near vision tests were performed, and presence and severity of diabetic retinopathy and diabetic macular edema, indicators of DM control such as fasting plasma glucose and glycosylated hemoglobin, and anthropometric measures were assessed using standardized protocols. Depression status and level of physical activity were measured using validated questionnaires. Adjusted logistic regression models were used to examine the association between near and distance vision impairment and cognitive impairment tested with a 6-item cognitive impairment test.

RESULTS

Participants (n = 501) were aged 66 ± 11 (mean ± SD) years, and their mean duration of DM was 14 ± 10 years. In adjusted models, near (P = 0.016) but not distance (P = 0.984) vision impairment was associated with cognitive impairment. Persons with near vision impairment were almost 4 times more likely to have cognitive impairment (odds ratio 3.90; 95% confidence interval, 1.31-12.56; P = 0.023), after adjusting for age, sex, and other covariables.

CONCLUSIONS

Our findings suggest common risk factors and pathways may exist between near vision impairment and cognitive dysfunction in patients with type 2 DM. Future studies need to further assess this link.

Visual impairment as a function of visual acuity in both eyes and its impact on patient reported preferences

Purpose

To assess the impact of VA loss on patient reported utilities taking both eyes into account compared to taking only the better or the worse eye into account.

Methods

In this cross-sectional study 1085 patients and 254 controls rated preferences with the generic health-related (EQ-5D; n = 868) and vision-specific (Vision and Quality of Life Index (VisQoL); n = 837) multi-attribute utility instruments (MAUIs). Utilities were calculated for three levels of VA in the better and worse eyes, as well as for 6 different vision states based on combinations of the better and worse eye VA.

Results

Using the VisQoL, utility scores decreased significantly with deteriorating vision in both the better and worse eyes when analysed separately. When stratified by the 6 vision states, VisQoL utilities decreased as VA declined in the worse eye despite stable VA in the better eye. Differences in VisQoL scores were statistically significant for cases where the better eye had no vision impairment and the worse seeing fellow eye had mild, moderate or severe vision impairment. In contrast, the EQ-5D failed to capture changes in better or worse eye VA, or any of the six vision states.

Conclusions

Calculating utilities based only on better eye VA or using a generic MAUI is likely to underestimate the impact of vision impairment, particularly when the better eye has no or little VA loss and the worse eye is moderately to severely visually impaired. These findings have considerable implications for the assessment of overall visual impairment as well as economic evaluations within eye health.

Factors associated with knowledge of diabetes in patients with type 2 diabetes using the Diabetes Knowledge Test validated with Rasch analysis

OBJECTIVE

In patients with Type 2 diabetes, to determine the factors associated with diabetes knowledge, derived from Rasch analysis, and compare results with a traditional raw scoring method.

RESEARCH DESIGN & METHODS

Participants in this cross-sectional study underwent a comprehensive clinical and biochemical assessment. Diabetes knowledge (main outcome) was assessed using the Diabetes Knowledge Test (DKT) which was psychometrically validated using Rasch analysis. The relationship between diabetes knowledge and risk factors identified during univariate analyses was examined using multivariable linear regression. The results using raw and Rasch-transformed methods were descriptively compared.

RESULTS

181 patients (mean age±standard deviation = 66.97±9.17 years; 113 (62%) male) were included. Using Rasch-derived DKT scores, those with greater education (β = 1.14; CI: 0.25,2.04, p = 0.013); had seen an ophthalmologist (β = 1.65; CI: 0.63,2.66, p = 0.002), and spoke English at home (β = 1.37; CI: 0.43,2.31, p = 0.005) had significantly better diabetes knowledge than those with less education, had not seen an ophthalmologist and spoke a language other than English, respectively. Patients who were members of the National Diabetes Service Scheme (NDSS) and had seen a diabetes educator also had better diabetes knowledge than their counterparts. Higher HbA1c level was independently associated with worse diabetes knowledge. Using raw measures, access to an ophthalmologist and NDSS membership were not independently associated with diabetes knowledge.

CONCLUSIONS

Sociodemographic, clinical and service use factors were independently associated with diabetes knowledge based on both raw scores and Rasch-derived scores, which supports the implementation of targeted interventions to improve patients' knowledge. Choice of psychometric analytical method can affect study outcomes and should be considered during intervention development.

An update on the molecular actions of fenofibrate and its clinical effects on diabetic retinopathy and other microvascular end points in patients with diabetes

The drug fenofibrate has received major attention as a novel medical treatment for diabetic retinopathy (DR) and other diabetes-induced microvascular complications. This interest stems from two recent large, well-designed clinical trials that demonstrated large reductions in the progression of DR and the need for laser intervention, in addition to a reduction in renal and neurological outcomes, in patients with type 2 diabetes. In both trials, the greatest benefit on DR progression was observed in those patients with DR at baseline. Originally considered a lipid-modifying drug, it now appears that multiple mechanisms may underpin the benefit of fenofibrate on diabetic microvascular end points. Fenofibrate regulates the expression of many different genes, with a range of beneficial effects on lipid control, inflammation, angiogenesis, and cell apoptosis. These factors are believed to be important in the development of DR regardless of the underlying diabetes etiology. Cell experiments have demonstrated improved survival of retinal endothelial and pigment epithelial cells in conjunction with reduced stress signaling under diabetic conditions. Further, fenofibrate improves retinal outcomes in rodent models of diabetes and retinal neovascularization. Given the results of these preclinical studies, further clinical trials are needed to establish the benefits of fenofibrate in other forms of diabetes, including type 1 diabetes. In DR management, fenofibrate could be a useful adjunctive treatment to modifiable risk factor control and regular ophthalmic review. Its incorporation into clinical practice should be continually revised as more information becomes available.

Reliability and reproducibility of retinal oxygen saturation measurements using a predefined peri-papillary annulus

PURPOSE

To determine the reliability and reproducibility of the Vesselmap Oximetry Module for arteriolar and venular oxygen saturation (SO2 ) of the same retinal area, specified by a peripapillary annulus, in healthy subjects.

METHODS

Fundus oximetry images were obtained, using a standardized protocol by a single observer, from the right eye of 20 healthy individuals. Age range was 19-45 years old, and images were analysed using the oximetry module of the Vesselmap System (Imedos, UG, Germany). Intra-observer reliability (assessment of two measurements of SO2 values performed 5 days apart); interobserver reliability (assessment of SO2 performed by two different trained observers); and intrasubject reproducibility (comparison of SO2 measurements of two different images of the same subject and retinal area, taken 10 min apart) were assessed. The standard deviations between the repeated measurements (SDr), together with the intraclass correlation coefficient (ICC), of these three parameters were calculated.

RESULTS

The SDr for intra-observer reliability was 0.56% and 0.55% for arteriolar and venular SO2 , respectively. The results were similar for intrasubject reproducibility (0.69% and 0.79% for arteriolar and venular SO2, respectively); interobserver reliability, however, was higher (SDr 1.22% and 1.01% for arteriolar and venular SO2 , respectively). The ICC values for intra-observer reliability were 0.99 for both arteriolar and venular SO2 . The results were similar for both interobserver reliability (0.94 for arteriolar SO2 and 0.96 for venular SO2 ) and intrasubject reproducibility (0.98 for both arteriolar and venular SO2 ).

CONCLUSION

Retinal oxygen saturation values taken using the oximetry module of the Vesselmap System are highly reliable and reproducible, provided the image quality is standardized, the same measurement area is analysed in each image, and the number of observers analysing the images is kept to a minimum.

Using Rasch analysis to evaluate the validity of the diabetes-specific version of the Illness Perception Questionnaire–Revised

This study used Rasch analysis to examine the psychometric validity of the Illness Perception Questionnaire–Revised to assess beliefs about diabetes in 470 participants with Type 2 diabetes and 71 participants with Type 1 diabetes. All Illness Perception Questionnaire–Revised scales had psychometric issues, which included poorly utilised response categories, poor scale precision and multidimensionality. Following re-engineering, only four of the eight scales (Consequences, Illness coherence, Timeline cyclical and Emotional representations) were psychometrically adequate according to the Rasch model. The diabetes-specific version of the Illness Perception Questionnaire–Revised provides suboptimal assessment of beliefs held by patients with diabetes.

Retinal arteriolar dilation to flicker light is reduced on short-term retesting

PURPOSE

To investigate the impact of retesting frequency over a short period on flicker light-induced retinal vasodilation.

METHODS

Twenty healthy participants were included. The retinal vascular response to flicker light stimulation was assessed three times (at baseline and after 5 and 30 minutes of rest [tests 1, 2, and 3, respectively]) in each participant using the Dynamic Vessel Analyzer. Relative dilations of selected arteriole and venule segments during flicker stimulation and resting diameters were measured automatically. The mean vessel dilations and resting diameters were compared using repeated-measures analysis of variance.

RESULTS

Participants were young (mean [SD] age, 33.1 [5.7] years) and mostly female (70%). The mean (SD) maximum arteriolar dilations during flicker stimulation were 3.23% (2.06%), 2.44% (1.62%), and 3.36% (2.11%) in tests 1, 2, and 3, respectively. The mean (SD) venular dilations were 4.26% (1.28%), 3.81% (1.61%), and 4.43% (1.73%) in tests 1, 2, and 3, respectively. The mean arteriolar dilations were significantly different across the three tests (P < 0.001). Compared with test 1, arteriolar dilations were significantly reduced after 5 minutes (P = 0.008) but not 30 minutes (P = 0.437) of rest. No significant differences were found over time for the mean venular dilations (P = 0.128). Resting diameters of selected vessels were not significantly different between tests.

CONCLUSIONS

Retinal arteriolar dilation during flicker stimulation is reduced on short-term retesting, without a significant change in baseline vessel diameter, indicating decreased responsiveness to the flicker stimulus. Researchers should allow at least 30 minutes between consecutive tests to minimize suppression of the flicker response.

Prevalence of cataract surgery and visual outcomes in Indian immigrants in Singapore: the Singapore Indian eye study

Objective

To determine the prevalence of cataract surgery and factors associated with post-surgical visual outcomes in migrant Indians living in Singapore.

Research Design and Methods

We conducted a population-based study in 3,400 Indian immigrants residing in Singapore−the Singapore Indian Eye Study (SINDI). All participants underwent comprehensive medical eye examination and a standardized interview. Post-operative visual impairment (VI) was defined as best-corrected or presenting visual acuity (BCVA or PVA) of 20/60 or worse.

Results

The age- and gender-standardized prevalence of cataract surgery was 9.7% (95% confidence interval [CI]: 8.9%, 10.7%) in Singapore resident Indians. Post-operative VI defined by BCVA occurred in 10.9% eyes (87/795). The main causes of post-operative VI were diabetic retinopathy (20.7%), posterior capsular opacification (18.4%), and age-related macular degeneration (12.6%). Undercorrected refractive error doubled the prevalence of post-operative VI when PVA was used.

Conclusions

The rate of cataract surgery is about 10% in Indian residents in Singapore. Socioeconomic variables and migration had no significant impact on the prevalence of cataract surgery. Diabetic retinopathy was a major cause of post-operative VI in migrant Indians living in Singapore. Uncorrected postoperative refractive error remains an efficient way to improve vision.

Feedback of personal retinal images appears to have a motivational impact in people with non-proliferative diabetic retinopathy and suboptimal HbA1c: findings of a pilot study

AIM

To conduct a pilot study to explore the potential impact of visual feedback of personal retinal images on diabetes outcomes.

METHODS

Twenty-five participants with non-proliferative diabetic retinopathy and suboptimal HbA(1c) (> 53 mmol/mol; > 7%) were randomized to receive visual feedback of their own retinal images or to a control group. At baseline and 3-month follow-up, HbA(1c), standard measures of beliefs, diabetes-related distress and self-care activities were assessed.

RESULTS

In unadjusted models, relative to controls, the intervention group showed significantly greater improvement in HbA(1c) at 3-month follow-up (-0.6% vs. +0.3%, P < 0.01), as well as enhanced motivation to improve blood glucose management (P < 0.05).

CONCLUSIONS

This small pilot study provides preliminary evidence that visual feedback of personal retinal images may offer a practical educational strategy for clinicians in eye care services to improve diabetes outcomes in non-target compliant patients. A fully powered randomized controlled trial is required to confirm these findings and determine the optimal use of feedback to produce sustained effects.

Cardio-metabolic risk factors and prehypertension in persons without diabetes, hypertension, and cardiovascular disease

BACKGROUND

Prehypertension has been shown to be an early risk factor of cardiovascular disease (CVD). We investigated the prevalence and pattern of cardiometabolic risk factors in prehypertension in three ethnic Asian populations in Singapore.

METHODS

We examined data from Chinese (n=1177), Malay (n=774), and Indian (n=985) adults aged 40-80 years who participated in three independent population based studies conducted from 2004-2011 in Singapore who were free of diabetes, hypertension and previous CVD. Prehypertension was defined as systolic blood pressure (BP) 120-139 mm Hg or diastolic BP 80-89 mm Hg. Random blood glucose, glycated haemoglobin (HbA1c), body mass index (BMI), triglycerides, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol were examined as indicators of adverse cardiometabolic profile. The association between metabolic variables and prehypertension was examined using logistic regression models adjusting for potential confounders.

RESULTS

The prevalence of prehypertension was 59.8% (Chinese), 68.9% (Malays) and 57.7% Indians. Higher levels of blood glucose, HbA1c and BMI were significantly associated with prehypertension in all three ethnic groups, odds ratio (95% confidence interval) of prehypertension in Chinese, Malays and Indians were: 1.42 (1.10, 1.83), 1.53 (1.05, 2.24), 1.49 (1.13, 1.98) for high-glucose; 3.50 (1.01, 12.18), 3.72 (1.29, 10.75), 2.79 (1.31, 5.94) for high-HbA1c; 1.86 (1.34, 2.56), 2.96 (2.10, 4.18), 1.68 (1.28, 2.20) for high-BMI. In addition, higher levels of LDL cholesterol in Chinese and higher levels of triglycerides were significantly associated with prehypertension. These associations persisted when metabolic variables were analysed as continuous variables.

CONCLUSIONS

Higher levels of blood glucose, HbA1c and BMI were associated with prehypertension in all three ethnic groups in Singapore. Screening for prehypertension and lifestyle modifications could potentially reduce the burden of CVD in otherwise healthy Asian adults living in Singapore.

Lack of awareness of common eye conditions in the community

PURPOSE

Awareness of eye conditions aids health promotion activities and leads to better outcomes. We examined factors influencing the lack of awareness of common eye conditions in a population.

METHODS

The Singapore Malay Eye Study examined 3280 (78.7% response) Malays aged 40-80 years. We included 2112 (64.4%) participants with at least one of five eye conditions: 1504 (71.2%) with cataract, 1013 (47.8%) with myopia, 270 (12.8%) with diabetic retinopathy, 181 (8.6%) with age-related macular degeneration and 150 (7.1%) with glaucoma. Lack of awareness was defined in the questionnaire as not answering "yes" to previously being told by a doctor of having the eye condition.

RESULTS

Among 2112 participants, 83.2% were unaware of at least one of their eye conditions. After controlling for age, sex and socioeconomic factors, participants unaware of their eye condition were older (odds ratio, OR, 1.03, per 1 year, p < 0.001), had better visual acuity (OR 1.32, p = 0.04), lower education (OR 1.89, p < 0.001), poorer literacy (OR 1.44, p = 0.02), lower income (OR 1.73, p = 0.009), higher blood glucose (OR 1.08, per 1 mmol/L, p < 0.001), higher serum cholesterol (OR 1.20, per 1 mmol/L, p = 0.003), lower annual eye examination attendance (OR 2.08, p < 0.001) and were less likely to wear glasses (OR 2.90, p < 0.001) than those who were aware of their condition.

CONCLUSIONS

In this community-based population, 80% of those with common eye conditions were unaware of their condition.

Marital status and its relationship with the risk and pattern of visual impairment in a multi-ethnic Asian population

BACKGROUND

To examine whether marital status is a significant determinant of visual impairment (VI) in urban multi-ethnic Asian population.

METHODS

We conducted a population-based study of Singapore-resident ethnic Malays, Indians and Chinese aged ≥40 years. Ophthalmic examination included the assessment of presenting and best-corrected visual acuity (PVA and BCVA) using standardized procedures. Information regarding marital status and socioeconomic status were obtained from an interviewer-administered questionnaire.

RESULTS

Among the 10 033 participants, 7756 (77.3%) were married; 589 (5.9%) were single; 407 (4.1%) were separated and 1265 (12.6%) were widowed. Being single (never married) or widowed were significantly associated with best-corrected VI (BCVA < 20/40) and presenting VI (PVA < 20/40) (odds ratios: 1.37-1.59) compared with married people even after adjustment for age, sex and socioeconomic status. A marginal prediction model showed that the negative effect of unmarried status on VI increased with age and was stronger among Malays and Indians, but the influence did not vary with gender, educational level and diabetic status.

CONCLUSIONS

Unmarried status is associated with VI, particularly among elderly Malays and Indians. Our findings suggest that single and widowed adults may benefit from specific social support and eye care programmes.