Currently accepted at: JMIR Research Protocols
Date Submitted: Mar 18, 2026
Date Accepted: Jul 18, 2026
This paper has been accepted and is currently in production.
It will appear shortly on 10.2196/95588
The final accepted version (not copyedited yet) is in this tab.
Association of Light Exposure and Sleep Timing Indices with Ocular Biometry in Malaysian Chinese Preschoolers in Kuala Lumpur: Protocol for a Prospective Cohort Study
ABSTRACT
Background:
Environmental light exposure and sleep-wake timing have been implicated in myopia development; however, longitudinal data in preschool children remain limited, particularly regarding the influence of artificial indoor lighting and circadian-related behaviors.
Objective:
This study aims to investigate whether objectively measured daily light exposure and actigraphy-derived sleep timing are associated with longitudinal changes in axial length and choroidal thickness over 24 months in preschool children at high risk of myopia.
Methods:
This is a 24-month prospective cohort study enrolling 68 Chinese preschool children (aged 5 to 6 years) with at least one myopic parent in Malaysia. Participants wear a wrist-worn actigraphy device (GENEActiv) for 7 consecutive days at four distinct intervals: baseline, 6, 12, and 18 months. This repeated measures approach provides objective assessment of habitual photopic light exposure and sleep timing indices throughout the study period. Simultaneously, ocular biometry, including axial length and choroidal thickness, is measured at baseline and at 12-, 18-, and 24-month follow-ups using optical low-coherence reflectometry (Lenstar LS900) and optical coherence tomography (Cirrus OCT 5000). Linear Mixed-Effects Models will evaluate associations between time-varying light exposure, sleep timing indices, and ocular growth trajectories.
Results:
Ethical approval was obtained from the Institutional Ethics Committee (Ref: IEC-2023-FMHS-0025). Recruitment for the baseline cohort commenced in April 2024. As of March 2026, longitudinal follow-ups are ongoing. Preliminary results are anticipated for dissemination in late 2026.
Conclusions:
This study will provide longitudinal evidence on the relationship between objectively measured light exposure, sleep timing, and ocular growth in preschool children. The findings will be instrumental in developing evidence-based “light-hygiene” interventions to mitigate early-onset myopia. Clinical Trial: Not applicable. This is a prospective observational cohort study and does not involve an intervention; therefore, clinical trial registration was not required at the time of study initiation. The protocol has been reviewed and approved by the UCSI Institutional Ethics Committee (Ref: IEC-2023-FMHS-0025).
Citation
Request queued. Please wait while the file is being generated. It may take some time.
Copyright
© The authors. All rights reserved. This is a privileged document currently under peer-review/community review (or an accepted/rejected manuscript). Authors have provided JMIR Publications with an exclusive license to publish this preprint on it's website for review and ahead-of-print citation purposes only. While the final peer-reviewed paper may be licensed under a cc-by license on publication, at this stage authors and publisher expressively prohibit redistribution of this draft paper other than for review purposes.