Table 3. Associations between near work activity, outdoor activity, parental myopia, and myopia in children.
| Variables | Total, n (%) | Myopia, n (%) | No myopia, n (%) | P-valuea |
|---|---|---|---|---|
| Daily hours of reading or studying for school assignments | ||||
| ≤2 h | 1867 (100) | 766 (41.0) | 1101 (59.0) | <0.001 |
| >2 h | 1111 (100) | 664 (59.8) | 447 (40.2) | |
| Daily hours of reading for pleasure | ||||
| None | 526 (100) | 229 (43.5) | 297 (56.5) | 0.041 |
| ≤2 h | 2272 (100) | 1105 (48.6) | 1167 (51.4) | |
| >2 h | 187 (100) | 99 (52.9) | 88 (47.1) | |
| Weekly hours of watching television | ||||
| None | 391 (100) | 156 (39.9) | 235 (60.1) | <0.001 |
| <2 h | 1288 (100) | 542 (42.0) | 746 (58.0) | |
| 2–4 h | 842 (100) | 448 (53.2) | 394 (46.8) | |
| >4 h | 472 (100) | 301 (63.8) | 171 (36.2) | |
| Weekly hours of using computer | ||||
| None | 495 (100) | 220 (44.4) | 275 (55.6) | <0.001 |
| <2 h | 1081 (100) | 482 (44.6) | 599 (55.4) | |
| 2–4 h | 809 (100) | 414 (51.2) | 395 (48.8) | |
| >4 h | 590 (100) | 316 (53.6) | 274 (46.4) | |
| Weekly hours of playing electronics | ||||
| None | 217 (100) | 55 (25.3) | 162 (74.7) | <0.001 |
| <2 h | 818 (100) | 318 (38.9) | 500 (61.1) | |
| 2–4 h | 868 (100) | 457 (52.6) | 411 (47.4) | |
| >4 h | 1076 (100) | 602 (55.9) | 474 (44.1) | |
| Distance of reading | ||||
| <25 cm | 2126 (100) | 1120 (52.7) | 1006 (47.3) | <0.001 |
| 25–29 cm | 593 (100) | 239 (40.3) | 354 (59.7) | |
| >29 cm | 226 (100) | 63 (27.9) | 163 (72.1) | |
| Distance of watching television | ||||
| <3 m | 1402 (100) | 703 (50.1) | 699 (49.9) | 0.044 |
| 3–5 m | 1230 (100) | 575 (46.7) | 655 (53.3) | |
| >5 m | 306 (100) | 132 (43.1) | 174 (56.9) | |
| Daily hours of outdoor activity | ||||
| <2 h | 2072 (100) | 1032 (49.8) | 1040 (50.2) | 0.212 |
| 2–3 h | 436 (100) | 197 (45.2) | 239 (54.8) | |
| >3 h | 327 (100) | 159 (48.6) | 168 (51.4) | |
| Number of parents with myopia | ||||
| None | 1999 (100) | 874 (43.7) | 1125 (56.3) | <0.001 |
| One parent | 783 (100) | 415 (53.0) | 368 (47.0) | |
| Two parents | 238 (100) | 144 (60.5) | 94 (39.5) | |
a
χ2 tests were used to examine the differences between myopia and no myopia group.