Table 2.
The associations between factors and the prevalence of myopia.
| Parameters | All (n = 556) | School A (n = 310) | School B (n = 246) | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Myopia (n = 354) | Normal (n = 202) | P value | Myopia (n = 201) | Normal (n = 109) | P value | Myopia (n = 153) | Normal (n = 93) | P value | |
| Change class seats, n (%) | |||||||||
| Never | 0 (0.0%) | 5 (100.0%) | 0.030 | 0 (0.0%) | 3 (100.0%) | 0.115 | 0 (0.0%) | 2 (100.0%) | 0.202 |
| Once a semester | 5 (55.6%) | 4 (44.4%) | 2 (50.0%) | 2 (50.0%) | 3 (60.0%) | 2 (40.0%) | |||
| Once a month | 49 (65.3%) | 26 (34.7%) | 43 (68.3%) | 20 (31.7%) | 6 (50.0%) | 6 (50.0%) | |||
| Once a fortnight | 256 (64.0%) | 144 (36.0%) | 145 (65.6%) | 76 (34.4%) | 111 (62.0%) | 68 (38.0%) | |||
| Once a week | 44 (66.7%) | 22 (33.3%) | 11 (57.9%) | 8 (42.1%) | 33 (70.2%) | 14 (29.8%) | |||
|
| |||||||||
| Adjust the height of desks and chairs, n (%) | |||||||||
| Never | 88 (66.7%) | 44 (33.3%) | 0.008 | 37 (61.7%) | 23 (38.3%) | 0.629 | 51 (70.8%) | 21 (29.2%) | <0.001 |
| Once a year | 44 (48.4%) | 47 (51.6%) | 19 (70.4%) | 8 (29.8%) | 25 (39.1%) | 39 (60.9%) | |||
| Once a semester | 176 (65.9%) | 91 (34.1%) | 104 (63.0%) | 61 (37.0%) | 72 (70.6%) | 30 (29.4%) | |||
| Once every 2 to 3 months | 46 (70.8%) | 19 (29.2%) | 41 (70.7%) | 17 (29.3%) | 5 (71.4%) | 2 (28.6%) | |||
|
| |||||||||
| Activity place during recess, n (%) | |||||||||
| Teaching building | 264 (63.9%) | 149 (36.1%) | 0.908 | 153 (66.5%) | 77 (33.5%) | 0.293 | 111 (60.7%) | 72 (39.3%) | 0.319 |
| Outside teaching building | 90 (63.4%) | 52 (36.6%) | 48 (60.0%) | 32 (40.0%) | 42 (67.7%) | 20 (32.3%) | |||
|
| |||||||||
| Time for homework per day, n (%) | |||||||||
| <1 h | 52 (65.0%) | 28 (35.0%) | 0.828 | 48 (69.6%) | 21 (30.4%) | 0.196 | 4 (36.4%) | 7 (63.6%) | 0.280 |
| 1–1.99 h | 157 (63.1%) | 92 (36.9%) | 88 (66.2%) | 45 (33.8%) | 69 (59.5%) | 47 (40.5%) | |||
| 2–2.99 h | 106 (65.4%) | 56 (34.6%) | 47 (63.5%) | 27 (36.5%) | 59 (67.0%) | 29 (33.0%) | |||
| ≥3 h | 37 (62.7%) | 22 (37.2%) | 18 (56.3%) | 14 (43.8%) | 19 (70.4%) | 8 (29.6%) | |||
| Uncertain | 2 (40.0%) | 3 (60.0%) | 0 (0.0%) | 2 (100.0%) | 2 (66.7%) | 1 (33.3%) | |||
|
| |||||||||
| Time for interest classes per week, n (%) | |||||||||
| 0 h | 57 (60.0%) | 38 (40.0%) | 0.862 | 33 (67.3%) | 16 (32.7%) | 0.789 | 24 (52.2%) | 22 (47.8%) | 0.665 |
| <1 h | 17 (60.7%) | 11 (39.3%) | 14 (58.3%) | 10 (41.7%) | 3 (75.0%) | 1 (25.0%) | |||
| 1–1.99 h | 66 (64.7%) | 36 (35.3%) | 43 (67.2%) | 21 (32.8%) | 23 (60.5%) | 15 (39.5%) | |||
| 2–2.99 h | 81 (62.3%) | 49 (37.7%) | 37 (59.7%) | 25 (40.3%) | 44 (64.7%) | 24 (35.3%) | |||
| ≥3 h | 129 (66.2%) | 66 (33.8%) | 73 (66.4%) | 37 (33.6%) | 56 (65.9%) | 29 (34.1%) | |||
| Uncertain | 4 (80.0%) | 1 (20.0%) | 1 (100.0%) | 0 (0.0%) | 3 (75.0%) | 1 (25.0%) | |||
|
| |||||||||
| Parents limit sports time for study, n (%) | |||||||||
| Often | 28 (60.9%) | 18 (39.1%) | 0.788 | 17 (65.4%) | 9 (34.6%) | 0.996 | 11 (55.0%) | 9 (45.0%) | 0.523 |
| Sometimes | 111 (65.7%) | 58 (34.3%) | 60 (64.5%) | 33 (35.5%) | 51 (67.1%) | 25 (32.9%) | |||
| Never | 215 (63.2%) | 125 (36.8%) | 124 (64.9%) | 67 (35.1%) | 91 (61.1%) | 58 (38.9%) | |||
|
| |||||||||
| Parents limit electronic products, n (%) | |||||||||
| Yes | 323 (64.3%) | 179 (35.7%) | 0.399 | 182 (66.2%) | 93 (33.8%) | 0.165 | 141 (62.1%) | 86 (37.9%) | 0.701 |
| No | 31 (58.5%) | 22 (41.5%) | 19 (54.3%) | 16 (45.7%) | 12 (66.7%) | 6 (33.3%) | |||
|
| |||||||||
| Sit more than one-punch distance from the edge of the table when reading and writing, n (%) | |||||||||
| Never | 23 (59.0%) | 16 (41.0%) | 0.560 | 15 (57.7%) | 11 (42.3%) | 0.606 | 8 (61.5%) | 5 (38.5%) | 0.981 |
| Sometimes | 108 (62.1%) | 66 (37.9%) | 57 (62.6%) | 34 (37.4%) | 51 (61.4%) | 32 (38.6%) | |||
| Often | 129 (62.9%) | 76 (37.1%) | 56 (63.6%) | 32 (36.4%) | 73 (62.4%) | 44 (37.6%) | |||
| Always | 94 (68.6%) | 43 (31.4%) | 73 (69.5%) | 32 (30.5%) | 21 (65.6%) | 11 (34.4%) | |||
|
| |||||||||
| The distance between eyes and books is more than 33 cm when reading and writing, n (%) | |||||||||
| Never | 21 (53.8%) | 18 (46.2%) | 0.276 | 15 (57.7%) | 11 (42.3%) | 0.606 | 7 (50.0%) | 7 (50.0%) | 0.660 |
| Sometimes | 114 (62.3%) | 69 (37.7%) | 57 (62.6%) | 34 (37.4%) | 52 (66.7%) | 26 (33.3%) | |||
| Often | 137 (63.4%) | 79 (36.6%) | 56 (63.6%) | 32 (36.4%) | 79 (61.2%) | 50 (38.8%) | |||
| Always | 82 (70.1%) | 35 (29.9%) | 73 (69.5%) | 32 (30.5%) | 15 (62.5%) | 9 (37.5%) | |||
|
| |||||||||
| The distance between fingers and nib is about 3.3 cm when reading and writing, n (%) | |||||||||
| Never | 31 (53.4%) | 27 (46.6%) | 0.062 | 15 (53.6%) | 13 (46.4%) | 0.073 | 16 (53.3%) | 14 (46.7%) | 0.723 |
| Sometimes | 65 (61.9%) | 40 (38.1%) | 38 (61.3%) | 24 (38.7%) | 27 (62.8%) | 16 (37.2%) | |||
| Often | 125 (61.3%) | 79 (38.7%) | 44 (57.9%) | 32 (42.1%) | 81 (63.3%) | 47 (36.7%) | |||
| Always | 133 (70.7%) | 55 (29.3%) | 104 (72.2%) | 40 (27.8%) | 29 (65.9%) | 15 (34.1%) | |||
|
| |||||||||
| Teachers remind the gestures of reading and writing, n (%) | |||||||||
| Never | 28 (65.1%) | 15 (34.9%) | 0.224 | 18 (66.7%) | 9 (33.3%) | 0.906 | 10 (62.5%) | 6 (37.5%) | 0.143 |
| Sometimes | 75 (56.4%) | 58 (43.6%) | 46 (61.3%) | 29 (38.7%) | 29 (50.0%) | 29 (50.0%) | |||
| Often | 90 (64.7%) | 49 (35.3%) | 47 (65.3%) | 25 (34.7%) | 43 (64.2%) | 24 (35.8%) | |||
| Always | 161 (67.1%) | 79 (32.9%) | 90 (66.2%) | 46 (33.8%) | 71 (68.3%) | 33 (31.7%) | |||
|
| |||||||||
| Parents remind the gestures of reading and writing, n (%) | |||||||||
| Never | 13 (48.1%) | 14 (51.9%) | 0.145 | 9 (50.0%) | 9 (50.0%) | 0.379 | 4 (44.4%) | 5 (55.6%) | 0.462 |
| Sometimes | 60 (64.5%) | 33 (35.5%) | 37 (67.3%) | 18 (32.7%) | 23 (60.5%) | 15 (39.5%) | |||
| Often | 108 (60.3%) | 71 (39.7%) | 55 (61.1%) | 35 (38.9%) | 53 (59.6%) | 36 (40.4%) | |||
| Always | 173 (67.6%) | 83 (32.4%) | 100 (68.0%) | 47 (32.0%) | 73 (67.0%) | 36 (33.0%) | |||
|
| |||||||||
| Watching TV per day, n (%) | |||||||||
| Never | 51 (66.2%) | 26 (33.8%) | 0.085 | 33 (68.8%) | 15 (31.3%) | 0.051 | 18 (62.1%) | 11 (37.9%) | 0.494 |
| <1 h | 187 (61.5%) | 117 (38.5%) | 93 (61.6%) | 58 (38.4%) | 94 (61.4%) | 59 (38.6%) | |||
| 1–1.99 h | 86 (69.4%) | 38 (30.6%) | 56 (69.1%) | 25 (30.9%) | 30 (69.8%) | 13 (30.2%) | |||
| 2–2.99 h | 21 (72.4%) | 8 (27.6%) | 14 (87.5%) | 2 (12.5%) | 7 (53.8%) | 6 (46.2%) | |||
| 3–3.99 h | 3 (75.0%) | 1 (25.0%) | 1 (50.0%) | 1 (50.0%) | 2 (100.0%) | 0 (0.0%) | |||
| ≥4 h | 6 (35.3%) | 11 (64.7%) | 4 (33.3%) | 8 (66.7%) | 2 (40.0%) | 3 (60.0%) | |||
|
| |||||||||
| Using computers per day, n (%) | |||||||||
| Never | 190 (64.0%) | 107 (36.0%) | 0.250 | 122 (66.7%) | 61 (33.3%) | 0.221 | 68 (59.6%) | 46 (40.4%) | 0.637 |
| <1 h | 138 (65.4%) | 73 (34.6%) | 57 (65.5%) | 30 (34.5%) | 81 (65.3%) | 43 (34.7%) | |||
| 1–1.99 h | 21 (52.5%) | 19 (47.5%) | 17 (51.5%) | 16 (48.5%) | 4 (57.1%) | 3 (42.9%) | |||
| 2–2.99 h | 3 (100.0%) | 0 (0.0%) | 3 (100.0%) | 0 (0.0%) | 0 | 0 | |||
| 3–3.99 h | 2 (50.0%) | 2 (50.0%) | 0 | 0 | 0 | 0 | |||
| ≥4 h | 2 (50.0%) | 2 (50.0%) | 0 | 0 | |||||
|
| |||||||||
| Using mobile devices more than 1 hour per day, n (%) | |||||||||
| Yes | 278 (63.3%) | 161 (36.7%) | 0.744 | 48 (63.2%) | 28 (36.8%) | 0.724 | 28 (68.3%) | 13 (31.7%) | 0.378 |
| No | 76 (65.0%) | 41 (35.0%) | 153 (65.4%) | 81 (34.6%) | 125 (61.0%) | 80 (39.0%) | |||
|
| |||||||||
| Reading books or electronic screens in direct sunlight, n (%) | |||||||||
| Never | 264 (62.3%) | 160 (37.7%) | 0.205 | 159 (64.9%) | 86 (35.1%) | 0.543 | 105 (58.7%) | 74 (41.3%) | 0.151 |
| Sometimes | 79 (68.7%) | 36 (31.3%) | 33 (63.5%) | 19 (36.5%) | 46 (73.0%) | 17 (27.0%) | |||
| Often | 4 (50.0%) | 4 (50.0%) | 3 (50.0%) | 3 (50.0%) | 1 (50.0%) | 1 (50.0%) | |||
| Always | 7 (87.5%) | 1 (12.5%) | 6 (85.7%) | 1 (14.3%) | 1 (100.0%) | 0 (0.0%) | |||
|
| |||||||||
| Turn off the light when looking at the electronic screen after dark, n (%) | |||||||||
| Never | 282 (63.5%) | 162 (36.5%) | 0.899 | 171 (65.0%) | 92 (35.0%) | 0.997 | 111 (61.3%) | 70 (38.7%) | 0.572 |
| Sometimes | 61 (66.3%) | 31 (33.7%) | 21 (63.6%) | 12 (36.4%) | 40 (67.8%) | 19 (32.2%) | |||
| Often | 5 (55.6%) | 4 (44.4%) | 4 (66.7%) | 2 (33.3%) | 1 (33.3%) | 2 (66.7%) | |||
| Always | 6 (60.0%) | 4 (40.0%) | 5 (62.5%) | 3 (37.5%) | 1 (50.0%) | 1 (50.0%) | |||
|
| |||||||||
| Reading or looking at electronic screens by lying, n (%) | |||||||||
| Never | 189 (64.3%) | 105 (35.7%) | 0.732 | 121 (65.4%) | 64 (34.6%) | 0.256 | 68 (62.4%) | 41 (37.6%) | 0.968 |
| Sometimes | 129 (62.9%) | 76 (37.1%) | 64 (64.0%) | 36 (36.0%) | 65 (61.9%) | 40 (38.1%) | |||
| Often | 31 (62.0%) | 19 (38.0%) | 12 (57.1%) | 9 (42.9%) | 19 (65.5%) | 10 (34.5%) | |||
| Always | 5 (83.3%) | 1 (16.7%) | 4 (100.0%) | 0 (0.0%) | 1 (50.0%) | 1 (50.0%) | |||
|
| |||||||||
| Reading or looking at electronic screens when walking or taking a bus, n (%) | |||||||||
| Never | 278 (63.2%) | 162 (36.8%) | 0.805 | 165 (65.5%) | 87 (34.5%) | 0.756 | 113 (60.1%) | 75 (39.9%) | 0.376 |
| Sometimes | 71 (65.7%) | 37 (34.3%) | 33 (61.1%) | 21 (38.9%) | 38 (70.4%) | 16 (29.6%) | |||
| Often | 5 (71.4%) | 2 (28.6%) | 3 (75.0%) | 1 (25.0%) | 2 (66.7%) | 1 (33.3%) | |||
| Always | 0 | 0 | 0 | 0 | 0 | 0 | |||
|
| |||||||||
| The lamp used when reading after dark, n (%) | |||||||||
| Both desk lamp and roof lamp | 230 (65.2%) | 123 (34.8%) | 0.354 | 125 (64.8%) | 68 (35.2%) | 0.237 | 105 (65.6%) | 55 (34.4%) | 0.362 |
| Only desk lamp | 24 (53.3%) | 21 (46.7%) | 14 (50.0%) | 14 (50.0%) | 10 (58.8%) | 7 (41.2%) | |||
| Only roof lamp | 99 (63.5%) | 57 (36.5%) | 61 (69.3%) | 27 (30.7%) | 38 (55.9%) | 30 (44.1%) | |||
| Others | 1 (100.0%) | 0 (0.0%) | 1 (100.0%) | 0 (0.0%) | 0 | 0 | |||
|
| |||||||||
| The distance between eyes and screens more than 66 cm when using computers, n (%) | |||||||||
| Never using computers | 115 (68.9%) | 52 (31.1%) | 0.483 | 77 (73.3%) | 28 (26.7%) | 0.238 | 38 (61.3%) | 24 (38.7%) | 0.844 |
| Never | 34 (59.6%) | 23 (40.4%) | 12 (54.5%) | 10 (45.5%) | 22 (62.9%) | 13 (37.1%) | |||
| Sometimes | 72 (62.6%) | 43 (37.4%) | 26 (63.4%) | 15 (36.6%) | 46 (62.2%) | 28 (37.8%) | |||
| Often | 57 (64.8%) | 31 (35.2%) | 23 (60.5%) | 15 (39.5%) | 34 (68.0%) | 16 (32.0%) | |||
| Always | 76 (59.4%) | 52 (40.6%) | 63 (60.6%) | 41 (39.4%) | 13 (54.2%) | 11 (45.8%) | |||
|
| |||||||||
| The distance between eyes and TV more than 3 m when watching TV, n (%) | |||||||||
| Never watching TV | 28 (65.1%) | 15 (34.9%) | 0.319 | 17 (70.8%) | 7 (29.2%) | 0.318 | 11 (57.9%) | 8 (42.1%) | 0.123 |
| Never | 27 (62.8%) | 16 (37.2%) | 13 (52.0%) | 12 (48.0%) | 14 (77.8%) | 4 (22.2%) | |||
| Sometimes | 101 (70.6%) | 42 (29.4%) | 39 (70.9%) | 16 (29.1%) | 62 (70.5%) | 26 (29.5%) | |||
| Often | 72 (63.2%) | 42 (36.8%) | 45 (70.3%) | 19 (29.7%) | 27 (54.0%) | 23 (46.0%) | |||
| Always | 126 (59.4%) | 86 (40.6%) | 87 (61.3%) | 55 (38.7%) | 39 (55.7%) | 31 (44.3%) | |||
|
| |||||||||
| Time on outdoor activities at daytime per day, n (%) | |||||||||
| <1 h | 60 (59.4%) | 41 (40.6%) | 0.130 | 39 (62.9%) | 23 (37.1%) | 0.276 | 21 (53.8%) | 18 (46.2%) | 0.343 |
| 1–1.99 h | 184 (68.9%) | 83 (31.1%) | 110 (69.2%) | 49 (30.8%) | 74 (68.5%) | 34 (31.5%) | |||
| 2–2.99 h | 61 (62.2%) | 37 (37.8%) | 23 (67.6%) | 11 (32.4%) | 38 (59.4%) | 26 (40.6%) | |||
| ≥3 h | 40 (54.1%) | 34 (45.9%) | 24 (53.3%) | 21 (46.7%) | 16 (55.2%) | 13 (44.8%) | |||
| Uncertain | 9 (60.0%) | 6 (40.0%) | 5 (50.0%) | 5 (50.0%) | 4 (80.0%) | 1 (20.0%) | |||
|
| |||||||||
| Sleeping time more than 8 h, n (%) | |||||||||
| Yes | 346 (64.6%) | 190 (35.4%) | 0.025 | 197 (66.1%) | 101 (33.9%) | 0.043 | 149 (62.6%) | 89 (37.4%) | 0.724 |
| No | 8 (40.0%) | 12 (60.0%) | 4 (33.3%) | 8 (66.7%) | 4 (50.0%) | 4 (50.0%) | |||
|
| |||||||||
| Father or mother has myopia, n (%) | |||||||||
| Yes | 222 (69.4%) | 98 (30.6%) | 0.001 | 120 (70.6%) | 50 (29.4%) | 0.019 | 102 (68.0%) | 48 (32.0%) | 0.024 |
| No | 132 (56.2%) | 103 (43.8%) | 81 (57.9%) | 59 (42.1%) | 51 (53.7%) | 44 (46.3%) | |||
|
| |||||||||
| Performed the examination of myopia in the past year, n (%) | |||||||||
| Yes | 336 (64.2%) | 187 (35.8%) | 0.361 | 189 (65.4%) | 100 (34.6%) | 0.444 | 147 (62.8%) | 87 (37.2%) | 0.814 |
| No | 18 (56.3%) | 14 (43.8%) | 12 (57.1%) | 9 (42.9%) | 6 (54.5%) | 5 (45.5%) | |||