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Axial length elongation profiles from 3 to 6 years in an Asian paediatric population: the Growing Up in Singapore Towards Healthy Outcomes birth cohort study (GUSTO)
  1. David Ziyou Chen1,2,
  2. Charlene Wong1,3,
  3. Janice Sing Harn Lam1,2,
  4. Chen-Hsin Sun1,2,
  5. Yien Lai1,2,
  6. Victor Teck Chang Koh1,2,
  7. Yap-Seng Chong4,5,
  8. Seang-Mei Saw6,7,8,
  9. Yih-Chung Tham2,6,8,
  10. Cheryl Ngo1
  1. 1 Department of Ophthalmology, National University Hospital, Singapore
  2. 2 Centre for Innovation and Precision Eye Health & Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
  3. 3 Department of Ophthalmology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
  4. 4 Department of Obstetrics and Gynaecology, Yong Loo School of Medicine, National University of Singapore, Singapore
  5. 5 Singapore Institute for Clinical Sciences, Agency for Science, Technology, and Research, Singapore
  6. 6 Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
  7. 7 Saw Swee Hock School of Public Health, National University Singapore, Singapore
  8. 8 Eye Academic Clinical Program, Duke-NUS Medical School, Singapore
  1. Correspondence to Dr Yih-Chung Tham, Centre for Innovation and Precision Eye Health, Department of Ophthalmology, National University of Singapore Yong Loo Lin School of Medicine, Singapore, Singapore; thamyc{at}; Dr David Ziyou Chen; david_chen{at}


Aims To determine axial length (AL) elongation profiles in children aged 3–6 years in an Asian population.

Methods Eligible subjects were recruited from the Growing Up in Singapore Towards Healthy Outcomes birth cohort. AL measurement was performed using IOLMaster (Carl Zeiss Meditec, Jena, Germany) at 3 and 6 years. Anthropometric measurements at birth, cycloplegic refraction at 3 and 6 years, questionnaires on the children’s behavioural habits at 2 years and parental spherical equivalent refraction were performed. Multivariable linear regression model with generalised estimating equation was performed to determine factors associated with AL elongation.

Results 273 eyes of 194 children were included. The mean AL increased from 21.72±0.59 mm at 3 years to 22.52±0.66 mm at 6 years (p<0.001). Myopic eyes at 6 years had greater AL elongation (1.02±0.34 mm) compared with emmetropic eyes (0.85±0.25 mm, p=0.008) and hyperopic eyes (0.74±0.16 mm, p<0.001). The 95th percentile limit of AL elongation was 1.59 mm in myopes, 1.34 mm in emmetropes and 1.00 mm in hyperopes. Greater birth weight (per 100 g, β=0.010, p=0.02) was significantly associated with greater AL elongation from 3 to 6 years, while parental and other behavioural factors assessed at 2 years were not (all p≥0.08).

Conclusion In this preschool cohort, AL elongates at an average length of 0.80 mm from 3 to 6 years, with myopes demonstrating the greatest elongation. The differences in 95th percentile limits for AL elongation between myopes, emmetropes and hyperopes can be valuable information in identifying myopia development in preschool children.

  • Epidemiology
  • Vision
  • Child health (paediatrics)

Data availability statement

Data may be provided upon reasonable request, subject to approval by the local ethics board.

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Data availability statement

Data may be provided upon reasonable request, subject to approval by the local ethics board.

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  • Y-CT and CN are joint senior authors.

  • X @Yih Chung Tham

  • Contributors Conceptualisation, methodology, validation: DC, CW, Y-SC, S-MS, Y-CT and CN. Data collection, data analysis and visualisation: DC and YCT. Manuscript creation: DC, CW, Y-CT. Critical review and supervision of manuscript: DC, CW, JL, C-HS, YL, VK, Y-SC, S-MS, CN and Y-CT. All authors read and approved the final manuscript. Y-CT accepts full responsibility for the work and/or the conduct of the study, had access to the data, and controlled the decision to publish.

  • Funding YCT is supported by the National Medical Research Council's Transition Award (NMRC/MOH/TA18nov-0002) and HPHSR Clinician Scientist Award (NMRC/MOH/ HCSAINV21nov-0001).

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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