Axial myopia has emerged as the leading cause of irreversible vision loss in East Asia, driven by its progression to sight-threatening complications including myopic macular degeneration, retinal detachment, open-angle glaucoma, and other complications. In the current study, we aim to observe the natural course of the development , progression, and its associated factors in children

This is a prospective epidemiological cohort study, recruiting students in grades 1-3 in primary school for myopia. Through stratified cluster random sampling, among aii the primary schools in Dongcheng District, Beijing, schools were stratified into key and ordinary schools, with 2 schools randomly selected from each stratum.

A prospective study cohort comprising 3,667 subjects was established. All study subjects completed a standard questionnaire and underwent routine ophthalmic examinations. Follow-up assessments will be conducted regularly to monitor changes in refractive errors and fundus indicators. Informed consent, approved by the Ethics Committee of Beijing Tongren Hospital, was obtained from all participants.

Inclusion Criteria: 1) Currently enrolled students in grades 1-3 of the selected primary schools, in good health, with normal ocular appearance. 2) No ocular diseases, no strabismus, ocular trauma, or history of intraocular surgery, with unaided visual acuity of 20/20 or better. 3) Parental and student consent to participate in the survey and signed informed consent form.

Exclusion Criteria: 1) Not currently enrolled in grades 1-3 of a primary school. 2) Students with pre-existing strabismus, other ocular diseases, or a history of ocular surgery at baseline, or those allergic to cycloplegic eyedrops. 3) Students unable to continue studying at their current school for more than three years from the baseline, including those who transfer to another school or withdraw from the study; 4) parental or student disagreement with participation in the survey.

Grades 1-3 primary school students.