This study aims to develop and evaluate a scalable, hybrid intervention model for the co-prevention of myopia, obesity, and mental health issues among children. By integrating cognitive behavioral therapy principles, the model targets key modifiable lifestyle factors-including dietary nutrition, physical activity, screen time, sleep hygiene, light exposure, and psychological adaptation-through coordinated family-school engagement and online-to-offline delivery. Using a cluster randomized controlled trial design in grades 3-4 primary school students, the research will assess the effectiveness of this multi-component strategy in reducing the incidence and burden of these co-occurring conditions.

This study employs a real-world, cluster randomized controlled trial (cRCT) design conducted in primary school settings. Participants will be provided with a 6-month integrated health education program involving both families and schools, accompanied by sustained environmental modifications to support healthy behaviors. Data will be collected at four time points: baseline, immediately after the intervention, 6 months, and 12 months post-baseline, to evaluate the short- and medium-term effects of the intervention.

Inclusion Criteria:

• Children in grades 3-4, aged 8-11 years.
• Informed consent obtained.

Exclusion Criteria:

• Presence of systemic diseases (e.g., endocrine, cardiac, psychiatric disorders).
• Presence of developmental abnormalities.
• Inability to complete the follow-up.