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.

• Wearable Device-Supported Myopia Prevention Program (Behavioral): The wearable device-supported program will use smart wearable wristbands to monitor outdoor activity time and provide reminders. Students in the intervention group will be encouraged to increase outdoor activity, with targets of at least 1 hour per day on school days and at least 2 hours per day on weekends. Data recorded by the wearable device will be used to quantify daily outdoor activity and assess adherence to the intervention.
• Eye Health Education (Behavioral): Routine school-based eye health education will include general guidance on healthy visual behaviors, including reducing prolonged near work, maintaining appropriate reading posture and lighting conditions, performing standard eye exercises, and undergoing regular eye examinations.

Primary outcomes

• Change in Axial Length [Baseline to 12 months]: Change in axial length is defined as the difference between axial length measured at 12 months and axial length measured at baseline.

Secondary outcomes

• Change in Cycloplegic Spherical Equivalent Refraction [Baseline to 12 months]: Change in cycloplegic spherical equivalent refraction is defined as the difference between the 12-month value and the baseline value.
• Incidence of Myopia During Follow-up [During the 12-month follow-up period]: Defined as the proportion of participants who develop myopia during follow-up, with myopia defined as uncorrected visual acuity less than 5.0 in either eye and non-cycloplegic spherical equivalent refraction less than -0.50 D in either eye.
• Adherence to Wearable Device Use [During the 12-month follow-up period]: Defined as adherence to wearing the study wearable device during the intervention period, as assessed using data recorded by the wearable device.
• Safety Outcomes and Adverse Events [During the 12-month follow-up period]: Defined as the occurrence of any adverse events related to wearable device use or increased outdoor activity, including skin irritation, device-related discomfort, eye discomfort related to sunlight exposure, or outdoor activity-related injuries.

Sex: All, ages: 6 Years to 11 Years, accepts healthy volunteers

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.