Audrey Chia

Duke-NUS Graduate Medical School Singapore, Tumasik, Singapore

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Publications (33)97.58 Total impact

  • G H Yap · L Y Chen · R Png · J L Loo · S Tow · R Mathur · A Chia
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    ABSTRACT: Purpose: To assess clinical value of visual electrophysiology in identifying causes of visual dysfunction in patients referred from neuro-ophthalmology clinics. Methods: A review of 410 subjects (aged 0.3-88 years) referred for visual electrophysiology from neuro-ophthalmologists between 2009 and 2013 was performed. Subjects were divided into those with unexplained poor vision, visual field defects, visual symptoms or other reasons (e.g. monitoring for drug toxicity or known conditions). Subjects underwent pattern, full-field and multifocal electroretinography (ERG) and pattern visual evoked potential (VEP) tests. Flash and multifocal VEP were included where indicated. Results: Most subjects referred for poor vision (n = 158) had electrophysiology findings suggestive of retinopathy (37 %) or post-retinal pathology (34 %). Those with poorer vision (worse than 6/24) were more likely to have abnormal recordings (86 vs. 62 %, p = 0.002). Among subjects with unexplained visual field defects (n = 102), findings of retinopathy, post-retinal pathology and normal recordings were noted in 31, 24 and 28 %, respectively. Most subjects with other visual symptoms (n = 97) had normal findings (69 %). The multifocal ERG was most sensitive for detecting retinopathy (96 %) and maculopathy (95 %), while pattern VEP was most sensitive for post-retinal pathology (94 %). An indeterminate result was noted in 9 %. Conclusion: Electrophysiology was effective in differentiating between retinopathy, post-retinal pathology and normality in 91 % of subjects. Pre-testing provisional diagnoses of retinopathy and post-retinal pathology were revised in 30 and 42 %, respectively, after electrophysiology. Appreciation of characteristics of each test, correlation with the clinical picture and interpretation of results in totality are required to localize the site of pathology.
    No preview · Article · Oct 2015 · Documenta Ophthalmologica
  • Audrey Chia · Qing-Shu Lu · Donald Tan
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    ABSTRACT: To compare the safety and efficacy of different concentrations of atropine eyedrops in controlling myopia progression over 5 years. Randomized, double-masked clinical trial. A total of 400 children originally randomized to receive atropine 0.5%, 0.1%, or 0.01% once daily in both eyes in a 2:2:1 ratio. Children received atropine for 24 months (phase 1), after which medication was stopped for 12 months (phase 2). Children who had myopia progression (≥-0.50 diopters [D] in at least 1 eye) during phase 2 were restarted on atropine 0.01% for a further 24 months (phase 3). Change in spherical equivalent and axial length over 5 years. There was a dose-related response in phase 1 with a greater effect in higher doses, but an inverse dose-related increase in myopia during phase 2 (washout), resulting in atropine 0.01% being most effective in reducing myopia progression at 3 years. Some 24%, 59%, and 68% of children originally in the atropine 0.01%, 0.1%, and 0.5% groups, respectively, who progressed in phase 2 were restarted on atropine 0.01%. Younger children and those with greater myopic progression in year 1 were more likely to require re-treatment. The lower myopia progression in the 0.01% group persisted during phase 3, with overall myopia progression and change in axial elongation at the end of 5 years being lowest in this group (-1.38±0.98 D; 0.75±0.48 mm) compared with the 0.1% (-1.83±1.16 D, P = 0.003; 0.85±0.53 mm, P = 0.144) and 0.5% (-1.98±1.10 D, P < 0.001; 0.87±0.49 mm, P = 0.075) groups. Atropine 0.01% also caused minimal pupil dilation (0.8 mm), minimal loss of accommodation (2-3 D), and no near visual loss compared with higher doses. Over 5 years, atropine 0.01% eyedrops were more effective in slowing myopia progression with less visual side effects compared with higher doses of atropine. Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.
    No preview · Article · Aug 2015 · Ophthalmology
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    ABSTRACT: This study aimed to evaluate the proportion of young patients with type 1 diabetes mellitus (T1DM) who have myopia, as well as the risk factors associated with myopia in this group. In this cross-sectional study, patients aged < 21 years with T1DM for ≥ 1 year underwent a comprehensive eye examination. Presence of parental myopia, and average hours of near-work and outdoor activity were estimated using a questionnaire. Annualised glycosylated haemoglobin (HbA1c), defined as the mean of the last three HbA1c readings taken over the last year, was calculated. Multivariate analysis using genetic, environmental and diabetes-related factors was done to evaluate risk factors associated with myopia. Of the 146 patients (mean age 12.5 ± 3.6 years) recruited, 66.4% were Chinese and 57.5% were female. Myopia (i.e. spherical equivalent [SE] of -0.50 D or worse) was present in 96 (65.8%) patients. The proportion of patients with myopia increased from 25.0% and 53.6% in those aged < 7.0 years and 7.0-9.9 years, respectively, to 59.2% and 78.4% in those aged 10.0-11.9 years and ≥ 12.0 years, respectively. Higher levels of SE were associated with lower parental myopia (p = 0.024) and higher annualised HbA1c (p = 0.011). Compared to the background population, the proportion of myopia in young patients with T1DM was higher in those aged < 10 years but similar in the older age group. Myopia was associated with a history of parental myopia. Environmental risk factors and poor glycaemic control were not related to higher myopia risk.
    No preview · Article · Aug 2015 · Singapore medical journal
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    ABSTRACT: To determine the psychological effects of eyedrops administration in children. Children requiring eyedrops for cycloplegic refraction were recruited in this cross-sectional study. Nurses administered eyedrops in 2-3 cycles spaced 5-10 minutes apart, and optometrists performed refraction 30 minutes after the last drop. Ophthalmologists, nurses, and optometrists rated the children's cooperation level at first review, after each eyedrop, at refraction, and at final review. Parents chose a personality type best describing their child, and monitored their child's anxiety using a modified Yale Preoperative Anxiety Scale (m-YPAS). Children were "uncooperative" if nurses noted significant distress during the first drop cycle. A total of 298 children 2-12 years of age were included. Of these, 77 (26%) experienced pre-drop distress and 39 (13%) were uncooperative with drops. Compared to cooperative children, uncooperative children tended to be younger (2.0-4.9 years vs ≥8 years; OR, 4.11; 95% CI, 1.14-14.83; P = 0.031), male (OR, 2.55; 95% CI, 1.06-6.10; P = 0.036), have had a previous negative eyedrop experience (84.2% vs 25.3%; P < 0.001) and were more anxious (m-YPAS scores, 41.4 ± 22.0 vs 30.6 ± 12.6: P < 0.001). Children described as "demanding and aggressive" were more uncooperative than "timid and anxious" children. It took longer to instill drops (3.1 vs 1.3 minutes), and perform refraction (11.6 vs 7.2 minutes) in uncooperative children. A small group of children were uncooperative with eyedrops and 26% experienced significant pre-drop anxiety. Factors such as age, sex, a previous negative eyedrop experience, and pre-drop anxiety, associated with uncooperativeness need to be considered when developing strategies to improve the eyedrops experience in children. Copyright © 2015 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.
    No preview · Article · Aug 2015 · Journal of AAPOS: the official publication of the American Association for Pediatric Ophthalmology and Strabismus / American Association for Pediatric Ophthalmology and Strabismus
  • Arjunan Kumaran · Hla M Htoon · Donald Tan · Audrey Chia
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    ABSTRACT: To analyze changes in refraction and associated biometric changes in atropine- and placebo-treated eyes in the Atropine for Treatment of Myopia study (ATOM1). A total of 400 myopic children, aged 6 to 12 years, were assigned randomly to receive 1% atropine or a placebo agent in one eye daily for 2 years, after which drops were stopped and children monitored for another year. Cycloplegic autorefraction, A-scan biometry, and automated keratometry were performed at the initial visit, 2 weeks (baseline), and at 4, 8, 12, 16, 20, 24, 30, and 36 months. A total of 313 children (78.3%) completed the study. In placebo-treated eyes, there was myopic progression of -1.55 diopters (D), between baseline and 36 months, associated with reductions in corneal curvature (K; -0.13 D) and anterior chamber depth (ACD; -0.17 mm) and increases in lens thickness (LT; 0.05 mm), vitreous chamber depth (VCD; 0.65 mm), and axial length (AL; 0.53 mm). Multivariate analysis of change in spherical equivalent demonstrated that the hyperopic shift (0.20 D) noted in atropine-treated eyes between baseline and 4 months, and the myopic rebound (-0.74 D) noted between 24 to 30 months when atropine was stopped, were associated with a reduction and increase in VCD and AL, respectively, after adjusting for age and sex. Changes in K, ACD, and LT were less relevant. Between 4 and 24 months, atropine-treated eyes demonstrated gradual myopic progression (-0.40 D), accompanied by reduction in K (-0.06 D) and ACD (-0.07 mm) and increase in VCD (0.13 mm) and AL (0.06 mm). Atropine appeared to slow myopia progression mainly by reducing or slowing the growth in VCD, and thereby AL. ( number, NCT00371124.).
    No preview · Article · Aug 2015 · Investigative ophthalmology & visual science
  • Kai-Lyn Loh · Qingshu Lu · Donald Tan · Audrey Chia
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    ABSTRACT: To investigate variables associated with myopic progression despite treatment in the Atropine in the Treatment of Myopia (ATOM-1) Study. Retrospective cohort study. 200 of 400 children were randomized to receive atropine 1% in one eye only in this institutional study. Children were followed up with cycloplegic autorefraction every 4 months over 2 years. Children whose myopia progressed by more than 0.5 Diopter (D) in atropine treated eye at 1 year were classified as being 'progressors'. There were 22 (12.1%) progressors amongst the 182 children still in the study at 1 year. Univariate analysis suggested these children tended to be younger (8.5±1.4years versus 9.3±1.5years, p=0.023), with higher myopic spherical equivalent (SE) at baseline (-3.6±1.3D versus -2.8±1.4D, p=0.015) and to have 2 myopic parents (77.3% versus 48.1%, p=0.012). In non-progressors, the myopia progression at 1 year was less in the atropine-treated compared to untreated fellow eyes (+0.16±0.37 D verus -0.73±0.48, p<0.001) but in progressors, progression was more similar between eyes (-0.92±0.31 versus -1.06±0.44, p=0.363). Regression analysis showed that the risk of being a progressor was 40% lower with each year of increased age, 43% lower for every 1.0 D less myopia at baseline, and 59% lower for every 1.0 D less myopic change in the untreated eyes over the first year. Doctors and parents need to be aware that there is a small group of children (younger, with higher myopia and greater tendency of myopic progression) who may still progress while on atropine treatment. Copyright © 2015 Elsevier Inc. All rights reserved.
    No preview · Article · Jan 2015 · American Journal of Ophthalmology
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    ABSTRACT: PurposeDespite a high prevalence of myopia among young East Asian adults, there is a lack of data on the myopic retina structure-function relationship in this group. We examined the association between optical coherence tomography (OCT) and electroretinogram (ERG) measurements in highly myopic young Asian adults to provide this information and also determined if OCT can be used as an alternative screening tool to assess retinal function in young myopic adults.Methods This was a prospective study comprising young adults aged between 18 and 25 years with spherical equivalent refraction of worse than −6.00 D. A comprehensive ophthalmic examination comprising fundus examination and grading, ocular biometry, time-domain OCT (fovea, macular and retinal nerve fibre layer thickness) and ERG (full field and multifocal) were performed for all the eyes.ResultsA total of 32 eyes (mean spherical equivalent ± standard deviation −10.17 ± 1.51 D, mean age 23.8 ± 1.3 years) were included. None of the eyes showed visible myopic retinopathy and the central retina thickness of all eyes was classified as within the normal range. Full-field ERG amplitude and multifocal ERG P1 amplitudes in the outer rings (R3-R5) were, however, inversely associated with axial length. The multifocal ERG P1 amplitudes were also positively correlated with mean retinal nerve fibre layer thickness in R2, 4, 5 rings and outer macular thickness in R 2–5 rings.Conclusion These findings suggest that full field ERG changes may precede fundus and OCT changes in highly myopic young adults. Although there was some correlation between multifocal ERG amplitudes with OCT outer macular and retinal nerve fibre layer thickness, the OCT may not be useful as a retinal function screening tool, being within normal limits in all eyes. Further longitudinal studies are required to determine how the relationship between ERG and OCT will evolve over time.
    Full-text · Article · Nov 2014 · Ophthalmic and Physiological Optics
  • Bryan Sim · Guan-Hui Yap · Audrey Chia
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    ABSTRACT: To quantify the effects of strabismus in Singaporean children using the Intermittent Exotropia Questionnaire (IXTQ) and the Adult Strabismus 20 Questionnaire (AS20). Consecutive strabismus patients 5-16 years of age were recruited along with an equal number of age-matched controls with eye conditions other than strabismus and amblyopia (group A) and controls with no known eye conditions (group B). All children completed the IXTQ; those8-16 years of age also completed the AS20 questionnaire. Parents completed the parental proxy IXTQ (pp-IXTQ) and AS20 (pp-AS20) and a parental IXTQ (PIXT). A total of 60 patients and 60 age-matched controls in each group were included. Children with strabismus had lower IXTQ (70.1 ± 19.0) and AS20 (80.0 ± 13.8) scores than those in group B (IXTQ, 90.3 ± 11.8 [P < 0.001]; AS20, 90.0 ± 10.9 [P < 0.001]) and group A (IXTQ, 80.6 ± 14.9 [P = 0.001]; AS20, 81.6 ± 18.3 [P = 0.691]). Among children with strabismus, child IXTQ scores were significantly lower than parental proxy scores (70.1 ± 19.0 vs 76.4 ± 15.8 [P = 0.026]), but there was no difference in control group scores or with AS20 scores. Item-level analysis suggested that children's worry focused on what others thought about them and their ability to make friends, whereas parents were more concerned about eyesight and whether surgery was required. The IXTQ and AS20 were better at differentiating between children with strabismus and those with no eye condition than between children with strabismus and other eye conditions. Parental proxies were accurate in predicting child scores but parents were more likely to underestimate the psychosocial effects of their children's strabismus.
    No preview · Article · Apr 2014 · Journal of AAPOS: the official publication of the American Association for Pediatric Ophthalmology and Strabismus / American Association for Pediatric Ophthalmology and Strabismus
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    ABSTRACT: To study the change in spherical equivalent and other ocular parameters 1 year after stopping the administration of atropine. Prospective randomized double-masked clinical trial. We assigned 400 myopic children, 6 to 12 years of age, to receive atropine 0.5%, 0.1% or 0.01% for 24 months, after which medication was stopped. Parents and children gave informed consent to participate in the research. Children were reviewed at 26, 32 and 36 months, and changes in cycloplegic spherical equivalent (SE), axial length (AL), visual acuity, pupil size, and accommodation were assessed. Of the children, 356 (89%) entered into the washout phase. At entry, there was no significant difference in age, gender, SE, or AL among the children in the various atropine groups. Over the following 12 months, myopic progression was greater in the 0.5% eyes (-0.87 ± 0.52 D), compared to the 0.1% (-0.68 ± 0.45 D) and 0.01% eyes (-0.28 ± 0.33 D, P < 0.001). AL growth was also greater in the 0.5% (0.35 ± 0.20 mm) and 0.1% (0.33 ± 0.18 mm) eyes, compared to the 0.01% eyes (0.19 ± 0.13 mm, P < 0.001). Pupil size and near visual acuity returned to pre-atropine levels in all groups, but accommodation at 36 months was less in the 0.5% eyes (13.24 ± 2.72 D) compared to the 0.1% (14.45 ± 2.61 D) and 0.01% eyes (14.04 ± 2.90 D, P < 0.001). The overall increase in SE over the entire 36 months in the 0.5%, 0.1% and 0.01% groups was -1.15 ± 0.81 D, -1.04 ± 0.83 D and -0.72 ± 0.72 D, respectively (P < 0.001). There was a myopic rebound after atropine was stopped, and it was greater in eyes that had received 0.5% and 0.1% atropine. The 0.01% atropine effect, however, was more modulated and sustained.
    No preview · Article · Dec 2013 · American Journal of Ophthalmology
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    ABSTRACT: To present a case series on the management options for capillary hemangiomas involving the eyelid and orbit. This is a retrospective chart review of clinically diagnosed capillary hemangioma cases involving the periocular region treated at two local eye institutions. The patients' demographics and clinical presentation - including visual acuity, refractive error, periorbital and orbital examinations, and ultrasound and magnetic resonance imaging findings - were reviewed. The clinical progression, modalities of treatment, and treatment outcomes were studied. Sixteen cases of capillary hemangiomas involving the eyelid and orbit were studied. The mean age at consultation was 9.6 months (range: 1 month-72 months). The majority were females (75%), with 50% presenting as upper-eyelid hemangiomas and the remaining as lower-eyelid (38%) and glabellar (12%) lesions. Combined superficial and deep involvement was common (64%). Cases whose lesions were located at the upper eyelid or superior orbit led to amblyopia (25%). Fifty-six percent of cases (9/16) were managed conservatively, and 44% (7/16) underwent treatment with either single-agent (n = 4) or combined treatments (n = 3). Close monitoring of visual development and prompt institution of amblyopia therapy for children with periocular capillary hemangiomas generally preserve vision. Extensive lesions that affect the visual axis require local and systemic treatments, alone or in combination, in order to reduce the size and impact of lesions on the eyeball, to reduce induced refractive error and visual occlusion, and to prevent the development of amblyopia, in order to achieve good visual outcomes.
    Full-text · Article · Jun 2013 · Clinical ophthalmology (Auckland, N.Z.)
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    ABSTRACT: Purpose: To determine the risk factors for strabismus and amblyopia in young Singapore Chinese children. Methods: A total of 3009 children were recruited for the population-based cross-sectional Strabismus, Amblyopia and Refractive Error in Singaporean Preschoolers Study (STARS). Strabismus was defined as any tropia identified on cover test. Visual acuity was measured in children aged 30-72 months with a logMAR chart where possible and the Sheridan-Gardiner test if not. Amblyopia was defined based on visual acuity and refractive error or presence of strabismus or past/present visual axis obstruction. Parents completed questionnaires on family, prenatal and birth histories. Results: Our study showed that 24 children aged 6-72 months (1.2%) had strabismus (20 with exotropia), and 20 children aged 30-72 months (0.8%) were amblyopic. After multivariate analysis, strabismus was associated with astigmatism ≥1.00 diopter (D; p = 0.03), amblyopia (p = 0.003), a sibling with strabismus (p < 0.001), and families with lower parental education (p = 0.04). In addition to strabismus, amblyopia was associated with anisometropia ≥1.00 D (p < 0.001) and astigmatism ≥1.00 D (p < 0.001). No association was noted between either strabismus or amblyopia and prematurity, maternal age or smoking. Conclusion: This study highlights the importance of family history in strabismus, and the close associations between refractive error and strabismus with amblyopia. These factors play a more important role in young Singapore Chinese children.
    No preview · Article · Jun 2013 · Ophthalmic epidemiology
  • Audrey Chia · Wen Li · Donald Tan · Chi D Luu
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    ABSTRACT: Background: The aims of this study were to determine the longitudinal effects of myopia on full-field electroretinogram (ffERG) in children, and whether there were any effects due to atropine treatment. Methods: Fifty children, enrolled in the atropine treatment for myopia study, were randomly selected and 35 children consented to undergo ffERG at baseline (prior to atropine treatment), 24 months (at end of treatment) and 32 months (8 months after cessation of treatment). An extended ISCEV ffERG protocol was used for all recordings. The relationship between axial length (AL) and the following scotopic and photopic ffERG responses was analyzed: a- and b-wave amplitude and implicit time, saturated amplitude (V max), and retinal sensitivity (logK). Results: Reliable ffERG recordings with acceptable level of noise were obtained on all 3 visits from 29 children (mean age: 9.5 ± 0.8 years and mean spherical equivalent: -5.0 ± 1.6 D). At baseline, the correlation detected between AL and logK was 0.37 (p = 0.047). There was no significant correlation between AL and V max or any scotopic and photopic ffERG amplitude and implicit time measures. Longitudinal data suggested a reduction in photopic a- and b-wave and 30 Hz flicker response amplitudes over time. Multivariate analysis showed that the change in 30 Hz flicker response amplitude was likely to be associated with AL change. There was no evidence that changes in other responses were associated with age, baseline AL, or atropine dose used. Conclusion: Retinal sensitivity was reduced in myopic children. There was a gradual decline in cone function over time which was not influenced by atropine treatment.
    No preview · Article · Jan 2013 · Documenta Ophthalmologica
  • Donald Tan · Audrey Chia · Chua Wei Han · Cheung Yin Bun

    No preview · Article · Dec 2012 · Ophthalmology
  • Donald Tan · Audrey Chia · Yin-Bun Cheung · Wei-Hand Chua

    No preview · Article · Aug 2012 · Ophthalmology
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    ABSTRACT: Our previous study, Atropine for the Treatment of Myopia 1 (ATOM1), showed that atropine 1% eyedrops were effective in controlling myopic progression but with visual side effects resulting from cycloplegia and mydriasis. The aim of this study was to compare efficacy and visual side effects of 3 lower doses of atropine: 0.5%, 0.1%, and 0.01%. Single-center, double-masked, randomized study. A total of 400 children aged 6-12 years with myopia of at least -2.0 diopters (D) and astigmatism of -1.50 D or less. Children were randomly assigned in a 2:2:1 ratio to 0.5%, 0.1%, and 0.01% atropine to be administered once nightly to both eyes for 2 years. Cycloplegic refraction, axial length, accommodation amplitude, pupil diameter, and visual acuity were noted at baseline, 2 weeks, and then every 4 months for 2 years. Myopia progression at 2 years. Changes were noted and differences between groups were compared using the Huber-White robust standard error to allow for data clustering of 2 eyes per person. The mean myopia progression at 2 years was -0.30±0.60, -0.38±0.60, and -0.49±0.63 D in the atropine 0.5%, 0.1%, and 0.01% groups, respectively (P=0.02 between the 0.01% and 0.5% groups; between other concentrations P > 0.05). In comparison, myopia progression in ATOM1 was -1.20±0.69 D in the placebo group and -0.28±0.92 D in the atropine 1% group. The mean increase in axial length was 0.27±0.25, 0.28±0.28, and 0.41±0.32 mm in the 0.5%, 0.1%, and 0.01% groups, respectively (P < 0.01 between the 0.01% and 0.1% groups and between the 0.01% and 0.5% groups). However, differences in myopia progression (0.19 D) and axial length change (0.14 mm) between groups were small and clinically insignificant. Atropine 0.01% had a negligible effect on accommodation and pupil size, and no effect on near visual acuity. Allergic conjunctivitis and dermatitis were the most common adverse effect noted, with 16 cases in the 0.1% and 0.5% atropine groups, and no cases in the 0.01% group. Atropine 0.01% has minimal side effects compared with atropine at 0.1% and 0.5%, and retains comparable efficacy in controlling myopia progression.
    No preview · Article · Sep 2011 · Ophthalmology
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    ABSTRACT: To examine the association between body fatness indices and retinal vascular calibre in Singapore Chinese children. We recruited 136 Singapore Chinese children aged 6-16 years from the STARS (The Strabismus, Amblyopia and Refractive Error Study in Singaporean Chinese Preschoolers) Family study in 2008-2010. Anthropometric measurements including weight, height and triceps skinfold (TSF) and right eye retinal photographs were performed. TSF was measured with Holtain-Tanner calliper on the back of the arm and midway between the point of the acromoion and olecranon process while the arm was hanging relaxed. TSF and BMI threshold (cut-off points for overweight and obesity) were defined as 85th and above of age- and gender-specific TSF and BMI standard charts which were based on American representative survey data. The mean retinal arteriolar and venular calibres were 155.78 ? 15.02 ?m and 219.66 ? 21.88 ?m, respectively in the STARS Family study. Each standard deviation (SD) increase in TSF (4.49 mm) and BMI (3.52 kg/m(2)) was associated with a 2.94 ?m (p = 0.012) and a 3.40 ?m (p = 0.005) widening in retinal venular calibre, respectively. Compared with children with TSF and BMI below threshold, children with TSF and BMI above threshold had a 10.21 ?m (p = 0.001) and a 9.33 ?m (p = 0.021) increase in retinal venular calibre, respectively. Greater TSF and BMI are associated with wider retinal venular calibre in healthy children aged 6 years and above. These findings suggest a possible effect of abnormal body fatness indices on early retinal vascular changes that reflect microvasculature in children.
    No preview · Article · Jun 2011 · International journal of pediatric obesity: IJPO: an official journal of the International Association for the Study of Obesity
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    ABSTRACT: Prior studies have reported that blood pressure (BP) has a significant influence on retinal vascular caliber both in adults and children aged 6 years and older. This study aimed to examine the association between BP and retinal vascular caliber in Singapore Chinese preschoolers 4 to 5 years of age. Population-based, cross-sectional study. A total of 385 eligible and healthy Singapore Chinese children 4 to 5 years of age who were recruited in The Strabismus, Amblyopia and Refractive Error Study in Singaporean Chinese Preschoolers from May 2006 through October 2008 underwent BP measurements and retinal photography. According to standard protocols, BP was measured with an automatic Omron sphygmomanometer (Omron HEM 705 LP, Omron Healthcare, Inc., Bannockburn, IL) and a retinal photograph was obtained with a Canon 45° digital retinal camera (Model CR6-NM45, Canon, Inc., Tokyo, Japan) after pupil dilation. Anthropometric and optical biometric measurements such as height, weight, and axial length were obtained also. Information regarding sociodemographic status and child birth information was supplied by parents in either English or Chinese questionnaires. The computer imaging program was used to measure the caliber of all retinal arterioles and venules located in zone B. The central retinal arteriolar equivalent and central retinal venular equivalent were estimated by using a revised Knudtson-Parr-Hubbard formula. The mean retinal arteriolar and venular calibers were 156.19 μm and 220.01 μm in boys and 161.97 μm and 224.22 μm in girls. Higher systolic BP was associated with narrower retinal arterioles. After adjusting for age, gender, father's education, body mass index, birth weight, axial length, and caliber of the fellow retinal vessel, each 10-mmHg increase in systolic BP was associated with 2.00 μm (95% confidence interval, 0.39-3.61; P = 0.02) of retinal arteriolar narrowing and 2.51 μm (95% confidence interval, 0.35-4.68; P = 0.02) of retinal venular widening. However, neither diastolic BP nor mean arterial BP was associated with retinal arteriolar or venular caliber. In very young children 4 to 5 years of age, higher systolic BP was associated with narrower retinal arterioles and wider retinal venules. This suggests that elevated BP may affect the retinal microvasculature from early childhood.
    No preview · Article · Mar 2011 · Ophthalmology
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    ABSTRACT: To describe the prevalence and causes of decreased visual acuity (VA) in Singaporean Chinese children. A population-based survey of Singaporean Chinese children aged 6 to 72 months was conducted. Participants underwent an orthoptic evaluation, cycloplegic refraction and biometric measurements. A sub-group of children aged 30 to 72 months with presenting logMAR VA were included in this analysis. Retesting was performed on the same day or another day by predefined criteria with best refractive correction. Decreased VA was defined as worse than 20/50 (0.4 logMAR) for ages 30 to 47 months and worse than 20/40 (0.3 logMAR) for ages 48 to 72 months. The study examined 3009 children (participation rate 72.3%) of which 2017 children aged 30 to 72 months were eligible for VA testing and completed in 1684 (83.5%). In children aged 30-47 months, the prevalence of decreased presenting VA was 2.1%, and in children 48-72 months, it was 2.05%, with no significant difference between boys and girls in both age groups (p=0.15 and p=0.85). Causes for decreased presenting VA in those 30-47 months were refractive error (7/11, 63.6%), amblyopia (1/11, 9.1%) and "no explanation" (3/11, 27.3%), and 17/24 (70.8%), 5/24 (20.8%) and 2/24 (8.3%), respectively, for those aged 48-72 months. The types of refractive error were astigmatism (15/24, 62.5%), myopia (6/24, 25.0%), hyperopia (2/24, 8.3%) and hyperopia with astigmatism (1/24, 4.2%). The prevalence of decreased VA among Singaporean Chinese preschoolers is low, with uncorrected refractive error being the main cause in both children 30-47 and 48-72 months.
    No preview · Article · Dec 2010 · The British journal of ophthalmology
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    ABSTRACT: To determine the psychometric validity of the pediatric quality of life inventory (PedsQL 4.0) in assessing the impact of refractive errors on health-related quality of life (HRQoL) in preschool children in Singapore. Parents of toddlers (aged 25 to 48 months) and young children (49 to 72 months) completed the PedsQL 4.0, an HRQoL scale as part of population-based trial in Singapore. The outcome measures were the overall score, and the "physical"; "emotional"; "social"; and "school" functioning subscales. Rasch analysis was used to validate the PedsQL 4.0. Parents of 939 (48.9%) toddlers and 982 (51.1%) young children completed the PedsQL 4.0 survey. The overall mean (±standard deviation) spherical equivalence for the right eye was 0.47 ± 1.13 diopter (D) for toddlers and 0.74 ± 1.22 D for young children. One hundred forty-nine (15.9%) toddlers and 90 (9.2%) young children were considered myopic (≥-0.50 D). Most participants (n = 1286, 89.6%) had presenting visual acuity 6/9 or better. Rasch analysis showed evidence of disordered category thresholds and poor person-item targeting for both groups. The separation reliability was 0.00 for toddlers and 0.03 for young children, indicating there was no variance in both samples. The PedsQL 4.0 overall and subscale scores displayed substantial multidimensionality as the variance values explained by the measures was <25% in both groups. A minimum value of 60% is usually considering acceptable. The PedsQL 4.0 in its current state is not a valid psychometric scale to effectively evaluate the impact of refractive errors on HRQoL in preschool children in Singapore.
    Full-text · Article · Nov 2010 · Optometry and vision science: official publication of the American Academy of Optometry
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    ABSTRACT: Peripheral hyperopia was hypothesized to stimulate axial elongation. This study describes peripheral refraction and its associations with central refractive error in young Singapore Chinese children. Two hundred fifty children aged 40 months or older recruited from the Strabismus, Amblyopia, and Refractive Error in Young Singapore Children study were included in this analysis. Peripheral refraction was measured after pupil dilation using an infrared autorefractor. A total of five measurements were captured: central visual axis and 15° and 30° eccentricities in the nasal and temporal visual fields. The mean age of the participants recruited was 83 ± 36 months. There were 37 children with high and moderate myopia (≤-3 D; 14.8%), 81 with low myopia (-2.99 to -0.5 D; 32.4%), 84 with emmetropia (-0.49 to 1.0 D; 33.6%), and 47 with hyperopia (>1.0 D; 18.8%). Compared with the central axis, children with high and moderate myopia had relative hyperopia at all peripheral eccentricities (P < 0.001), whereas children with low myopia had relative hyperopia only at the temporal and nasal 30° (P < 0.001), but not at the nasal and temporal 15°. Children with emmetropia and hyperopia had peripheral relative myopia at all eccentricities (P < 0.001). A significant correlation between the nasal and temporal refractive error at 30° was noted (Spearson's correlation coefficient = 0.85, P < 0.001). Young myopic Singapore Chinese children had relative hyperopia in the periphery. This study substantiates previous studies in older children and in Caucasian subjects.
    No preview · Article · Oct 2010 · Investigative ophthalmology & visual science

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530 Citations
97.58 Total Impact Points


  • 2015
    • Duke-NUS Graduate Medical School Singapore
      Tumasik, Singapore
  • 2014-2015
    • KK Women's and Children's Hospital
      Tumasik, Singapore
  • 2007-2015
    • Singapore Eye Research Institute
      Tumasik, Singapore
  • 2006-2014
    • Singapore National Eye Centre
      Tumasik, Singapore