School-based Myopia Prevention Trial for Children With Adequate Hyperopic Reserve

This prospective, school-based randomized controlled trial will be conducted among non-myopic children with adequate hyperopic reserve. Eligible participants are students in grades 1 to 4 from participating primary schools who meet the age-specific criteria for adequate hyperopic reserve based on cycloplegic spherical equivalent refraction in the worse eye and whose parents or legal guardians provide written informed consent.

Within each participating school, students will be stratified by grade and randomly assigned in a 1:1 ratio to the intervention group or the control group. The intervention group will receive routine school-based eye health education and wearable device-supported monitoring and reminders for outdoor activity. The control group will receive routine school-based eye health education and maintain usual daily activities without wearable device-supported outdoor activity monitoring or reminders.

Baseline and follow-up assessments will include ophthalmic examinations according to the study protocol. An interim follow-up assessment will also be conducted at 6 months, including visual acuity assessment, non-cycloplegic autorefraction, and axial length measurement. The primary outcome is the change in axial length from baseline to 12 months. Secondary outcomes include the change in cycloplegic spherical equivalent refraction, the incidence of myopia during follow-up, achievement of outdoor activity targets, adherence to wearable device use, and safety outcomes and adverse events.

Inclusion criteria

• Students in grades 1 to 4 from participating schools.
• Non-myopic children with adequate hyperopic reserve at baseline, defined as cycloplegic spherical equivalent refraction in the worse eye within the following age-specific reference ranges: +1.72 D to +2.45 D at age 6 years; +1.48 D to +2.00 D at age 7 years; +1.19 D to +1.79 D at age 8 years; +1.11 D to +1.38 D at age 9 years; +0.92 D to +1.16 D at age 10 years; and +0.83 D to +1.07 D at age 11 years.
• Written informed consent provided by a parent or legal guardian, with assent obtained from the child when appropriate.

Exclusion criteria

• Strabismus, amblyopia, or other ocular abnormalities.
• Systemic disease or other medical conditions that may affect study participation.
• Has received any myopia prevention intervention in the past 3 months.
• Any other condition judged by the study doctors to make participation inappropriate.