TABLE 3.
2-year cumulative incidence of myopia among primary school students according to the baseline SER (Shenzhen, China. 2019–2021).
| Baseline SER (D) | All | Boys | Girls | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n | Incidence, % | χ 2 * | P | n | Incidence, % | χ 2 * | P | n | Incidence, % | χ 2 * | P | |
| −0.5 < SER ≤0 | 2,060 | 54.1 | 420.40 | <0.001 | 1,112 | 49.2 | 229.21 | <0.001 | 948 | 59.7 | 190.20 | <0.001 |
| 0 < SER ≤0.5 | 1,949 | 36.3 | 1,102 | 31.6 | 847 | 42.4 | ||||||
| 0.5 < SER ≤1 | 607 | 15.5 | 343 | 11.7 | 264 | 20.5 | ||||||
| 1 < SER ≤1.5 | 109 | 10.1 | 60 | 10.0 | 49 | 10.2 | ||||||
| SER >1.5 | 80 | 2.5 | 49 | 0.0 | 31 | 6.5 | ||||||
SER, spherical equivalent refraction; D, diopters; *, Chi square test for trend.