Reading this plot:
C (green) Cycloplegic — Tier A, most reliable.
NC (orange) Non-cycloplegic — Tier B, overestimates ~10–20pp in children.
VA/Claims (red) Screening/admin data — Tier B.
Dot size reflects prevalence magnitude. Hover for study name.
What the apparent trend does NOT mean:
The upward drift over time reflects growing inclusion of East Asian urban studies in published literature,
not a simple global secular increase.
For within-country secular trends, use China, Taiwan, and Japan longitudinal data specifically.
Cross-country scatter plots should not be used to estimate rates of change.