Trial Parameters
Brief Summary
The primary objective of this multi-center, observational study is to establish the reference ranges of axial length in Chinese children and adolescents. 30,000 children aged 3-18 years were examined with cycloplegia to collect their ocular parameters and were all followed up for three years with annual visits.
Eligibility Criteria
Inclusion Criteria: * Aged 3 to 18 years * Have been lived in the research areas for at least one year, and will not move to other places in the following two years * Parents or guardians sign an informed consent form, and children over 6 years old need oral consent to participate Exclusion Criteria: * Mental diseases, unable to cooperate to complete the eye assessment * Ophthalmic diseases, inability to cooperate to complete the inspection