Characteristics of included and excluded Chinese schoolchildren (aged 6–10 years at baseline) in Wenzhou at baseline examination
| Included (N=1022) | Excluded (N=44) | P value | |
| Age, year | 7.8 (0.7) | 7.9 (0.7) | 0.25 |
| Gender | |||
| Male | 565 (55.3) | 28 (63.6) | 0.35 |
| Female | 457 (44.7) | 16 (36.4) | |
| School | |||
| Urban | 762 (74.6) | 19 (43.2) | <0.001 |
| Rural | 260 (25.4) | 25 (56.8) | |
| Grade | |||
| 2 | 535 (52.3) | 21 (47.7) | 0.66 |
| 3 | 487 (47.7) | 23 (52.3) | |
| Number of myopic parents | |||
| 0 | 380 (37.2) | 23 (52.3) | 0.05 |
| 1 | 387 (37.9) | 9 (20.5) | |
| 2 | 255 (25.0) | 12 (27.3) | |
| Baseline spherical equivalent, D | −0.2 (0.8) | −0.4 (1.0) | 0.12 |
| Baseline axial length, mm | 23.1 (0.8) | 23.3 (0.9) | 0.25 |
| Presenting visual acuity, decimal | 1.1 (0.4) | 1.0 (0.4) | 0.26 |
| Negative relative accommodation, D | 2.7 (0.8) | 2.8 (0.7) | 0.66 |
| Positive relative accommodation, D | −3.6 (2.0) | −3.1 (1.8) | 0.05 |
| Near work time, hours/day | 2.4 (2.3) | 2.4 (2.1) | 0.91 |
| Outdoor time, hours/day | 2.2 (1.9) | 2.2 (1.8) | 0.97 |
Data are expressed in N (%) or mean (SD).
D, diopter.