Differences in anterior ocular biometric characteristics among 6-year-old children with different myopic shift rates: A 2-year longitudinal study.

Background: To investigate longitudinal changes in anterior ocular features during slow and fast myopic shift in 6-year-old children.

Methods: In total, 242 eyes of first-year primary school children in Shanghai, China, were included in this study. All children underwent an initial examination and were subsequently followed-up for two years. All participants underwent comprehensive examinations, including ocular biometric assessment and cycloplegic autorefraction. Children were divided into two groups based on the degree of myopic shift in 2 years: group A (slow myopic shift, < 1.0 D, N = 145) and group B (fast myopic shift, > 1.0 D, N = 88). Detailed anterior ocular biometric data were compared between the two groups.

Results: In both groups, the axial length and anterior chamber depth (ACD) increased significantly over the follow-up period (P < 0.001). Anterior corneal surface curvature showed a flattening trend in both flat and steep meridians in group A, while these parameters exhibited steepening changes in group B. Lens thickness (LT) decreased significantly from 3.60 ± 0.20 mm to 3.45 ± 0.17 mm in group B (P < 0.001), but not in group A (P = 0.387). The average lens tilt significantly decreased from 5.21 ± 1.26° to 4.95 ± 1.23° in group A (P = 0.043), but it exhibited no significant change in group B (P = 0.181). Furthermore, LT and ACD were significantly correlated with spherical equivalent changes (P < 0.01).

Conclusions: Children with slow and fast myopic shift demonstrated comparable ACD deepening changes but showed distinct variations in corneal curvature and lens characteristics.