Table 1.
The epidemiological characteristics of poor vision
| Grade | Gender | Prevalence of poor vision (%) | Total (%) | Grade average (%) | Gender Chi-square test | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | χ2 | P | ||||
| 1st of Junior Middle School | Male | 76.86 | 76.44 | 76.56 | 77.12 | 79.01 | 77.96 | 77.53 | 81.86 | 689.72 | P < 0.001 |
| Female | 87.24 | 86.02 | 85.92 | 85.89 | 87.26 | 85.56 | 86.42 | ||||
| 2nd of Junior Middle School | Male | 80.58 | 81.96 | 82.20 | 80.66 | 84.99 | 83.23 | 82.58 | 86.12 | 557.72 | P < 0.001 |
| Female | 89.06 | 90.29 | 90.48 | 88.00 | 91.15 | 89.20 | 89.86 | ||||
| 3rd of Junior Middle School | Male | 84.06 | 84.39 | 84.58 | 85.13 | 87.08 | 86.67 | 85.41 | 88.51 | 455.92 | P < 0.001 |
| Female | 91.77 | 91.48 | 91.57 | 90.89 | 92.38 | 92.26 | 91.77 | ||||
| 1st of Senior Middle School | Male | -- | -- | -- | -- | 92.96 | 93.33 | 93.13 | 94.48 | 30.94 | P < 0.001 |
| Female | -- | -- | -- | -- | 95.21 | 96.64 | 95.82 | ||||
| 2nd of Senior Middle School | Male | 90.59 | 89.62 | 90.65 | 90.10 | 91.20 | 91.66 | 90.74 | 92.90 | 222.03 | P < 0.001 |
| Female | 95.47 | 94.55 | 94.97 | 95.11 | 95.53 | 94.22 | 95.05 | ||||
| 3rd of Senior Middle School | Male | -- | -- | -- | -- | 92.35 | 94.10 | 93.13 | 94.98 | 58.86 | P < 0.001 |
| Female | -- | -- | -- | -- | 96.16 | 97.46 | 96.78 | ||||
| Overall (%) | 86.95 | 86.09 | 86.57 | 85.73 | 89.08 | 88.67 | 87.40 | ||||
Note: The Cochran-Armitage trend test demonstrated a significant increase in poor vision prevalence with upward trends across grade-level (β = 0.027, z = 55.55, P-trend < 0.001) and survey years (β = 0.007, z = 15.64, P-trend < 0.001); Data for 1st and 3rd senior middle school grades were only available from 2022 onward, as these grades were not included in the surveillance program prior to that year; Missing data are denoted by “--”