Biomedical subjects

Seng-Chee Loon

Publications and source records attributed to Seng-Chee Loon.

3 recordsLinked to original sources

PubMed2006

Myopia, axial length, and OCT characteristics of the macula in Singaporean children.

PURPOSE: The purpose of this study was to evaluate the associations between macular volume and thickness, as assessed by optic coherence tomography (OCT), with refraction and axial length (AL) in children. METHODS: A total of 104 Chinese school children (51 girls and 53 boys) 11 to 12 years of age were randomly selected from one school during the 2005 examination in the Singapore Cohort Study of the Risk Factors for Myopia (SCORM). Cycloplegic autorefraction was performed to obtain refraction (defined as spherical equivalent [SE]) and ultrasound biometry performed to obtain the AL. Macular volume and thickness were then measured (StratusOCT3; Carl Zeiss Meditec, Dublin, CA). RESULTS: Children with moderate myopia (SE at least -3.0 D) tended to have smaller total macular volume and thinner quadrant-specific macular thickness (except in the inferior and superior inner quadrants), followed by children with low myopia (-0.5 -0.5 D). Total macular volume was positively associated with SE (beta=1.58, 95% CI, 0.84 to 2.32, standardized beta=0.14, P<0.001) and negatively associated with AL (beta=-1.20, 95% CI, -1.62 to -0.79, standardized beta=0.45, P<0.001) in multiple linear regression models controlling for age and gender. CONCLUSIONS: In children, increasing axial myopia was associated with reduced macular volume and thickness. These findings suggest that early anatomic changes may be present in the retinas of children with axial myopia.

Anthropometry↗

PubMed2006

Understanding the super-spreading events of SARS in Singapore.

INTRODUCTION: It has been noted that SARS transmission is characterised by a few super-spreading events (SSEs) giving rise to a disproportionate number of secondary cases. Clinical and environmental features surrounding the index cases involved were compared with cases in non- SSEs. MATERIALS AND METHODS: Data on 231 cases of probable SARS admitted to Tan Tock Seng Hospital (TTSH) were used. Index cases directly causing 10 or more secondary cases were classified as having been involved in SSEs; all others were defined as non-SSEs. RESULTS: Only 5 cases were involved in SSEs; all 5 were isolated on day 5 of illness or later, and spent at least a brief period in a non-isolation ward; in contrast, amongst the 226 non-SSE cases, only 40.7% and 4.0% were isolated late and admitted to non-isolation wards respectively, and only 3.1% had both these environmental features present; the differences were highly significant (P = 0.012, P <0.001 and P <0.001 by Fisher's Exact test). When compared to 7 non-SSE cases with delayed isolation and an admission to non-isolation wards, SSEs were more likely to have co-morbid disease or require ICU care at time of isolation (P = 0.045 for both factors). CONCLUSION: SSEs were likely due to a conglomeration of environmental factors of delayed isolation and admission to a non-isolation ward, coupled with severe disease stage at time of isolation.

Adult↗

PubMed2005

Iris ischaemic changes and visual outcome after acute primary angle closure.

BACKGROUND: Ischaemic changes in the iris occur frequently after an episode of acute primary angle closure (APAC). The aim of this study was to investigate the significance of such changes with regards to visual outcome. METHODS: Acute primary angle closure cases were treated with medical therapy followed by laser peripheral iridotomy after resolution of the acute episode. Subjects were examined at 1, 4, 8, 12 and 16 weeks post laser peripheral iridotomy. Eyes were examined for signs of iris ischaemic changes (IIC), defined as the presence of iris whorling or stromal atrophy. Iris photographs were also taken at weeks 1, 8 and 16. Subjects requiring glaucoma medication or filtering surgery during the follow-up period were excluded. The visual acuity and visual field (using automated white-on-white threshold perimetry) at week 16 were used in the assessment of visual outcome. RESULTS: Sixty-one subjects with APAC completed the study. The majority of subjects were female (82%) and Chinese (92%), and the mean age was 59 +/- 8.8 years. More than half the subjects (52.5%) were found to have developed IIC during the study, 65% of whom already had signs of IIC by the first week. Only 13 subjects (41%) with IIC and 6 subjects (21%) without IIC had an abnormal visual field defect at week 16 (P = 0.09). There was also no difference in visual acuity at week 16, the majority of subjects in both groups having visual acuity of 6/12 or better. CONCLUSIONS: The development of iris ischaemic changes after a single episode of APAC may not be associated with an adverse visual outcome.

Acute Disease↗