Table 2 Prevalence rates of astigmatism by student characteristics (N = 71,838)
Characteristics | n | Astigmatism ≤-0.75 D, n (%) | Astigmatism ≤-1.50 D, n (%) | Astigmatism ≤-3.0 D, n (%) | |
|---|---|---|---|---|---|
Age (years) | 7 | 6761 | 2056 (30.4) | 526 (7.8) | 99 (1.5) |
| Â | 8 | 7621 | 2457 (32.2) | 610 (8.0) | 113 (1.5) |
| Â | 9 | 7678 | 2481 (32.3) | 563 (7.3) | 122 (1.6) |
| Â | 10 | 7645 | 2500 (32.7) | 592 (7.7) | 112 (1.5) |
| Â | 11 | 8366 | 2833 (33.9) | 669 (8.0) | 126 (1.5) |
| Â | 12 | 7780 | 2889 (37.1) | 699 (9.0) | 143 (1.8) |
| Â | 13 | 5965 | 2350 (39.4) | 597 (10.0) | 95 (1.6) |
| Â | 14 | 5419 | 2198 (40.6) | 568 (10.5) | 119 (2.2) |
| Â | 15 | 4573 | 2029 (44.4) | 564 (12.3) | 113 (2.5) |
| Â | 16 | 3345 | 1456 (43.5) | 388 (11.6) | 85 (2.5) |
| Â | 17 | 3340 | 1421 (42.5) | 390 (11.7) | 78 (2.3) |
| Â | 18 | 2467 | 994 (40.3) | 237 (9.6) | 48 (1.9) |
| Â | 19 | 878 | 474 (32.0) | 62 (7.1) | 14 (1.6) |
χ2 |  | 627.487 | 218.533 | 54.354 | |
P-value | Â | <0.001 | <0.001 | <0.001 | |
Gender | Male | 36,607 | 13,844 (37.8) | 3646 (10.0) | 696 (1.9) |
| Â | Female | 35,231 | 12,101 (34.3) | 2819 (8.0) | 571 (1.6) |
χ2 |  | 93.709 | 84.075 | 8.155 | |
P-value | Â | <0.001 | <0.001 | 0.004 | |
Nationality | Han | 45,021 | 17,828 (39.6) | 4846 (10.8) | 878 (2.0) |
| Â | Uyghur | 12,763 | 3368 (26.4) | 579 (4.5) | 136 (1.1) |
| Â | Kazakhs | 1495 | 509 (34.0) | 102 (6.8) | 26 (1.7) |
| Â | Kyrgyz | 5277 | 1695 (32.1) | 306 (5.8) | 98 (1.8) |
| Â | Hui | 5298 | 1802 (34.0) | 462 (8.7) | 95 (1.8) |
| Â | Others | 1984 | 743 (37.4) | 170 (8.6) | 24 (1.2) |
χ2 |  | 811.136 | 557.162 | 51.008 | |
P-value | Â | <0.001 | <0.001 | <0.001 | |
Education stage | Primary school | 45,982 | 15,293 (33.3) | 3672 (8.0) | 707 (1.5) |
| Â | Junior high school | 16,068 | 6567 (40.9) | 1732 (10.8) | 344 (2.1) |
| Â | High school | 9788 | 4085 (41.7) | 1061 (10.8) | 216 (2.2) |
χ2 |  | 454.042 | 160.324 | 37.858 | |
P-value | Â | <0.001 | <0.001 | <0.001 | |
Spherical Equivalent (SE) | SE≤-6.00 D | 1128 | 852 (75.5) | 538 (47.7) | 170 (15.1) |
-6.00 D < SE≤-5.00 D | 1658 | 1047 (63.1) | 262 (15.8) | 49 (3.0) | |
|  | -5.00 D < SE≤-4.00 D | 2830 | 1528 (54.0) | 477 (16.9) | 52 (1.8) |
|  | -4.00 D < SE≤-3.00 D | 3958 | 2173 (54.9) | 767 (19.4) | 151 (3.8) |
|  | -3.00 D < SE≤-2.00 D | 5995 | 2834 (47.3) | 729 (12.2) | 148 (2.5) |
|  | -2.00 D < SE<-0.50 D | 19,937 | 6913 (34.7) | 1555 (7.8) | 270 (1.4) |
|  | -0.50 D ≤ SE ≤ + 0.50 D | 32,244 | 8347 (25.9) | 1340 (4.2) | 179 (0.6) |
|  | + 0.50 D ≤ SE < + 1.00 D | 2715 | 1471 (54.2) | 364 (13.4) | 64 (2.4) |
|  | + 1.00 D ≤ SE | 1373 | 780 (56.8) | 433 (31.5) | 184 (13.4) |
χ2 |  | 4724.538 | 4837.828 | 2649.796 | |
P-value | Â | <0.001 | <0.001 | <0.001 | |