Audrey Chia

Singapore National Eye Centre, Tumasik, Singapore

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Publications (25)73.95 Total impact

  • 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.
    Journal of AAPOS: the official publication of the American Association for Pediatric Ophthalmology and Strabismus / American Association for Pediatric Ophthalmology and Strabismus 04/2014; 18(2):178-82. · 1.07 Impact Factor
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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.
    American journal of ophthalmology 12/2013; · 3.83 Impact Factor
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    ABSTRACT: 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.
    Ophthalmic epidemiology 06/2013; 20(3):138-147. · 1.93 Impact Factor
  • 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.
    Documenta Ophthalmologica 01/2013; · 1.54 Impact Factor
  • Ophthalmology 12/2012; 119(12):2653–2654. · 5.56 Impact Factor
  • Ophthalmology 08/2012; 119(8):1718–1719. · 5.56 Impact Factor
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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.
    Ophthalmology 09/2011; 119(2):347-54. · 5.56 Impact Factor
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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.
    International journal of pediatric obesity: IJPO: an official journal of the International Association for the Study of Obesity 06/2011; 6(3-4):267-74. · 2.00 Impact Factor
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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.
    Ophthalmology 03/2011; 118(7):1459-65. · 5.56 Impact Factor
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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.
    The British journal of ophthalmology 12/2010; 94(12):1561-5. · 2.92 Impact Factor
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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.
    Optometry and vision science: official publication of the American Academy of Optometry 11/2010; 87(11):813-22. · 1.53 Impact Factor
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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.
    Investigative ophthalmology & visual science 10/2010; 52(2):1181-90. · 3.43 Impact Factor
  • Article: Reply.
    American journal of ophthalmology 03/2010; 149(3):523-4. · 3.83 Impact Factor
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    ABSTRACT: PURPOSE. To determine the prevalence of amblyopia and strabismus in young Singaporean Chinese children. METHODS. Enrolled in the study were 3009 Singaporean children, aged 6 to 72 months. All underwent complete eye examinations and cycloplegic refraction. Visual acuity (VA) was measured with a logMAR chart when possible and the Sheridan-Gardner test when not. Strabismus was defined as any manifest tropia. Unilateral amblyopia was defined as a 2-line difference between eyes with VA < 20/30 in the worse eye and with coexisting anisometropia (> or =1.00 D for hyperopia, > or =3.00 D for myopia, and > or =1.50 D for astigmatism), strabismus, or past or present visual axis obstruction. Bilateral amblyopia was defined as VA in both eyes <20/40 (in children 48-72 months) and <20/50 (<48 months), with coexisting hyperopia > or =4.00 D, myopia < or = -6.00 D, and astigmatism > or =2.50 D, or past or present visual axis obstruction. RESULTS. The amblyopia prevalence in children aged 30 to 72 months was 1.19% (95% confidence interval [CI], 0.73-1.83) with no age (P = 0.37) or sex (P = 0.22) differences. Unilateral amblyopia (0.83%) was twice as frequent as bilateral amblyopia (0.36%). The most frequent causes of amblyopia were refractive error (85%) and strabismus (15%); anisometropic astigmatism >1.50 D (42%) and isometropic astigmatism >2.50 D (29%) were frequent refractive errors. The prevalence of strabismus in children aged 6 to 72 months was 0.80% (95% CI, 0.51-1.19), with no sex (P = 0.52) or age (P = 0.08) effects. The exotropia-esotropia ratio was 7:1, with most exotropia being intermittent (63%). Of children with amblyopia, 15.0% had strabismus, whereas 12.5% of children with strabismus had amblyopia. CONCLUSIONS. The prevalence of amblyopia was similar, whereas the prevalence of strabismus was lower than in other populations.
    Investigative ophthalmology & visual science 03/2010; 51(7):3411-7. · 3.43 Impact Factor
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    ABSTRACT: It is common for refraction to be measured using different testing methods in children, with much debate still ongoing on the preferred method. Therefore, we compared cycloplegic refraction measurements using three objective methods in a large cohort of children. We present the findings from a total of 51 children who were recruited and examined as part of the Strabismus, Amblyopia and Refractive error in Singapore preschool children (STARS) study. Each child underwent a comprehensive eye examination, which included cycloplegic refraction using a hand-held autorefractor (Retinomax), a table mounted autorefractor (Canon FK-1) and streak retinoscopy. Spherical equivalent (SE) was calculated as (sphere + half of minus cylinder) and astigmatism was determined using the negative cylindrical component. The current study sample consisted of 29 boys and 22 girls aged between 24 and 72 months (mean age 52.3 months). The mean spherical equivalent (SE) using the table-mounted autorefractor (1.03 +/- 1.64 D) was not significantly different from the streak retinoscopy (1.09 +/- 1.58 D, p = 0.66). However, the mean SE using the hand-held Retinomax (0.80 +/- 1.43 D) was significantly different (more 'minus'p = 0.0004) to streak retinoscopy. The astigmatism measured using the hand held (-0.89 +/- 0.51 D) and table-mounted autorefractor (-0.83 +/- 0.61 D) were significantly greater than that obtained with streak retinoscopy (-0.58 +/- 0.56, p = 0.0003). The table-mounted autorefractor provided a reading more similar to that of streak retinoscopy than to that of the hand-held autorefractor. However, there were only small differences in mean SE (<0.32 D) between the hand-held Retinomax and the other methods, which will have implications in research investigations of refractive error.
    Ophthalmic and Physiological Optics 08/2009; 29(4):422-6. · 1.74 Impact Factor
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    ABSTRACT: To determine the testability of several vision and refraction tests in preschool-aged children. Population-based study of Chinese preschool-aged children in Singapore. One thousand five hundred and forty-two Singaporean Chinese children aged 6 to 72 months were recruited through door-to-door screening of government-subsidized apartments in Singapore. Trained eye professionals administered all tests, including monocular logarithm of the minimum angle of resolution visual acuity with the Sheridan Gardiner chart, monocular Ishihara color testing (Richmond Products Inc, Albuquerque, New Mexico, USA), biometric measurements using IOLMaster (Carl Zeiss, Jena, Germany), and Randot stereoacuity (Stereo Optical Co, Chicago, Illinois, USA) for children 30 to younger than 72 months. Cycloplegic refraction and keratometry measurements also were determined using a table-mounted autorefractor (Canon Autorefractor RK-F1; Canon, Tokyo, Japan) in children 24 to younger than 72 months. Testabilities were 84.8% for visual acuity (40.7% for age 30 to < 36 months, 70.8% for age 36 to < 42 months, 86.7% for age 42 to < 48 months, 94.8 for age 48 to < 54 months, 98.6 for age 54 to < 66 months, and 98.7% for age 66 to < 72 months), 81.1% for the Ishihara color test, 82.2% for Randot stereoacuity, 62.2% for table mounted autorefraction, and 91.7% for IOLMaster. All testabilities significantly increased with age (P < .0001). Girls had higher testability rates than boys for the autorefraction and Randot stereoacuity tests (P = .036 and .008, respectively). The vision and refraction tests were testable in a high proportion of preschool-aged Chinese Singaporeans. Preschool children in older age groups are likely to complete these tests successfully, with important implications for determining age limits for screening in the community and clinic.
    American journal of ophthalmology 06/2009; 148(2):235-241.e6. · 3.83 Impact Factor
  • A Chia, W-H Chua, D Tan
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    ABSTRACT: The aim of this study was to determine if topical atropine, used to retard axial length elongation and myopia progression, had any effect on ocular astigmatism. Data collected from subjects enrolled in the Atropine in the Treatment of Myopia (ATOM) study were analysed. In this study, 400 myopic children (aged 6-12 years) were randomly assigned to administer atropine 1% or a placebo daily to a randomly selected eye for 2 years. Cycloplegic autorefraction and keratomy readings were measured using a Canon RK5 autorefractor. The refractive error was then split into its power vector components: J0 and J45. Astigmatism increased by 0.12-0.16 D per year in both treated and placebo groups. There was no difference between groups (p = 0.182). The increase was mirrored by an increase in corneal astigmatism of 0.10-0.13 D per year, suggesting that most of the change was corneal in nature. There was an increase in J0 vector (with-the-rule astigmatism) with no change in the J45 (oblique) vector over time. The change in the J0 vector was significantly larger in the atropine-treated versus atropine-untreated eyes during the 2-year treatment period (p = 0.011), but this difference disappeared after atropine was stopped. The use of atropine on a daily basis over 2 years did not have any clinically significant effect on astigmatism.
    The British journal of ophthalmology 03/2009; 93(6):799-802. · 2.92 Impact Factor
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    ABSTRACT: To investigate the relationship of outdoor activities and myopia in Singapore teenage children. Teenage children (1249 participants), examined in the Singapore Cohort study Of Risk factors for Myopia (SCORM), during 2006 were included in analyses. Participants completed questionnaires that quantified total outdoor activity, and underwent an eye examination. The mean total time spent on outdoor activity was 3.24 h/day. The total outdoor activity (h/day) was significantly associated with myopia, odds ratio 0.90 (95% CI 0.84 to 0.96) (p = 0.004), after adjusting for age, gender, ethnicity, school type, books read per week, height, parental myopia, parental education and intelligence quotient. In addition, the total time spent outdoors was associated with significantly less myopic refraction (regression coefficient = 0.17; CI 0.10 to 0.25, p<0.001) and shorter axial length (regression coefficient -0.06 (CI -0.1 to -0.03, p<0.001). Total sports was also significantly negatively associated with myopia (p = 0.008) but not indoor sports (p = 0.16). Participants who spent more time outdoors were less likely to be myopic. Thus, outdoor activity may protect against development of myopia in children, supporting recent Australian data. As near work did not predict outdoor activity, this can be viewed as an independent factor and not merely the reciprocal of near work.
    The British journal of ophthalmology 02/2009; 93(8):997-1000. · 2.92 Impact Factor
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    ABSTRACT: X-linked red-green colour blindness is the most common form of colour blindness. Various studies suggest that, worldwide, 2-8% of men are afflicted with this condition. The purpose of this study is to determine the prevalence of red-green colour blindness in Singaporean schoolchildren. A total of 1249 children aged 13-15 years were screened using the Ishihara 24-plate edition book during the School Cohort study of the Risk factors for Myopia visit. A total of 1210 children (96.8%) managed to correctly identify at least 13 of the initial 15 plates and were deemed to have normal colour vision.Thirty-three children (32 boys, one girl) were only able to identify nine or less plates and were considered to be colour blind. Overall, 5.4% (95% confidence interval 3%, 7%) of Chinese, 4.9% (1%, 9%) of Malay and 4.9% (2%, 11%) of Indian boys were colour blind (P = 0.97). Classification plates 16-17 were useful in determining deutran or protan tendencies in only 14 (43%) of the 33 children identified as being colour blind. 5.3% of boys and 0.2% of girls were found to be colour blind in this Singapore-based study. Although the Ishihara test proved useful in identifying colour-blind children, other tests are required to accurately classify the types of red-green colour blindness in these children.
    Clinical and Experimental Ophthalmology 08/2008; 36(5):464-7. · 1.96 Impact Factor
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    Audrey Chia, Lipika Roy, Linley Seenyen
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    ABSTRACT: Recent studies suggest that Asian strabismus patterns are different from those in the West. This study aims to determine the profile of children with comitant horizontal strabismus in Singapore. 682 children aged <or=16 years presenting with strabismus for the first time between 2000 and 2002 were included in this study. The type and size of the squint, visual acuity, refractive error and stereopsis were noted. 493 children (72%) were exotropic, the majority (92%) of whom had intermittent exotropia, X(T). The divergence excess type X(T) was most common (59.5%), followed by basic (29.0%) and convergence-weakness (11.5%). Children with X(T) demonstrated stereopsis for near in 92% and distance in 50%. Esotropia was present in 191 (28%) children (23% infantile and 53% accommodative). Children with infantile esotropia presented significantly younger (2.8 years vs 4.5 years), had larger squint size (35D vs 26D) and were less hyperopic (+0.78D vs +2.79D). Amblyopia or ocular preference was noted in 50% of children with infantile esotropia, and 43% with accommodative esotropia. Twice as many Singaporean children presented with exotropia than esotropia. However, within the exotropia and esotropia groups, the distribution and characteristics of various strabismus subtypes bore similar characteristics to those described in the West.
    British Journal of Ophthalmology 11/2007; 91(10):1337-40. · 2.73 Impact Factor

Publication Stats

240 Citations
73.95 Total Impact Points

Institutions

  • 2005–2014
    • Singapore National Eye Centre
      Tumasik, Singapore
  • 2007–2013
    • Singapore Eye Research Institute
      Tumasik, Singapore
  • 2010
    • Royal Victorian Eye and Ear Hospital
      Melbourne, Victoria, Australia
  • 2009
    • National University of Singapore
      • Saw Swee Hock School of Public Health
      Singapore, Singapore