Axial Length

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.

This study is a randomized controlled trial based on outdoor activity interventions at specific time periods, involving preschool children aged 4 to 5 years. It compared the axial length and myopia incidence between the intervention group and the control group at the 6th and 12th months of the intervention to determine the effect of outdoor activities at specific time periods on the prevention of myopia in preschool children. Additionally, the study investigated the association between outdoor activities at specific time periods and axial length and myopia in preschool children.