Optimizing Light Exposure for Myopia Prevention and Control (LightSPAN)

The primary objective of the study is to evaluate whether the optimization of daily exposure to light in primary school children can lead to better myopia prevention and control. To do so, we will evaluate the effectiveness, safety and feasibility of:

• Arm 1: technical intervention which involves spectro-temporal refinement of classroom lighting in primary schools using full spectrum light emitting diodes (LEDs) (CCT: 4000K) in addition to intermittent fluctuations in light levels. Parents of children in that arm will have access to a sham version of the LightUP mobile application to facilitate communication with the study team and questionnaire collection during the study.
• Arm 2: digital intervention which involves optimization of daily light exposure using an individualised behaviour-changing smart-phone application (Interventional LightUP application) coupled with child-worn light and activity sensors to provide parents with an individually tailored recommendation to adapt their children's behaviour and provide them with the required amounts of myopia-preventive light quantum/day. + standard classroom lighting

As compared to:

• Arm 3: Standard care or control group which involves standard classroom lighting and no access to the interventional version of the LightUP application. Parents of children in that arm will have access to a sham version of the LightUP mobile application to facilitate communication with the study team and questionnaire collection during the study.

Our study will also lead to the following scalable and implementable outcomes:

• evidence-based lighting designs and policy recommendations for classrooms;
• a user-friendly, smart digital eyecare companion that aligns perfectly with Singapore's Smart Nation Initiative.

A secondary objective of this study is to better understand the impact of light exposure on sleep and cognitive performance in children. This will be achieved through continuous wrist actigraphy monitoring and through cognitive assessments, performed in classrooms, using tablets (one tablet/child). The assessment consists of validated, child-adapted, higher cognitive tasks testing the following constructs: impulse control, spatial working memory, content working memory, cognitive flexibility, reaction time, and processing speed.

Inclusion criteria

• Subject must meet all the inclusion criteria below to participate in this study.

• Written Informed Consent form from parent / legal guardian and assent from child subject has been obtained
• Is between 7 to 10 years of age at start of study intervention which is 2 January 2025 or 1 January 2026
• Studying in either Primary 2 or 3 classes of the participating school(s) in academic year 2025 or 2026.
• Presenting visual acuity or best corrected visual acuity (BCVA) better or equal to LogMAR 0.2 (equivalent to Snellen 6/9 or better) in each eye
• Normal Intraocular pressure (not more than 21mmHg)
• No ocular conditions (e.g., optic nerve disease, glaucoma, retinal diseases) except for refractive error.
• No ocular conditions affecting the accuracy of the ophthalmic examinations
• In good general health with no significant systemic diseases that may affect eye health

Exclusion criteria

• All subjects meeting any of the exclusion criteria at baseline will be excluded from participation.

• Previous or ongoing myopia control treatment (including but not limited to orthokeratology, atropine, pirenzepine, myopia control spectacle and contact lenses, light therapy)
• Ongoing participation in other myopia prevention and control research trials
• Any systemic or neurologic diseases (e.g. cancer, epilepsy, Kawasaki disease) known to affect eye health or make the participant vulnerable to the ophthalmic examinations (e.g., light flash)
• Any other conditions precluding adherence to the protocol including unwillingness to refrain from myopia control treatment for the duration of the study