Table 6.
Characteristics of participants with and without high myopia (N = 6832)
| Non high myopia#4 (N = 6495) | High myopia (N = 337) | P value | |
|---|---|---|---|
| Grade, median (IQR)#1 | 9 (6, 12) | 12 (9, 15) | < 0.001* |
| Age, median (IQR), year#1 | 10.9 (8.3, 13.5) | 14.8 (13.0, 16.5) | < 0.001* |
| Ethnicity, No. (%)#2 | |||
| Non-Han | 24 (0.4) | 4 (1.2) | 0.785 |
| Han | 6471 (99.6) | 333 (98.8) | |
| Sex, No. (%)#2 | |||
| Boys | 3349 (51.6) | 147 (43.6) | 0.004* |
| Girls | 3146 (48.4) | 190 (56.4) | |
| BMI, median (IQR)#1 | 17.959 (15.816, 20.703) | 19.234 (16.937, 21.565) | < 0.001* |
| Resident, No. (%)#2 | |||
| Village | 2863 (44.1) | 156 (46.3) | 0.426 |
| Urban | 3632 (55.9) | 181 (53.7) | |
| Parents’ high myopia, No. (%)#2 | |||
| None of them are high myopia | 6284 (96.8) | 319 (94.7) | 0.037* |
| At least one is high myopia | 211 (3.2) | 18 (5.3) | |
| Have any bad writing habits #3 ? No. (%) #2 | |||
| Have little bad writing habit | 2218 (34.1) | 102 (30.3) | < 0.001* |
| Have a kind of bad writing habit | 1337 (20.6) | 69 (20.5) | |
| Have two kinds of bad writing habits | 1116 (17.2) | 71 (21.1) | |
| Have three kinds of bad writing habits | 1096 (16.9) | 53 (15.7) | |
| Have four kinds of bad writing habits | 472 (7.3) | 28 (8.3) | |
| Have five kinds of bad writing habits | 256 (3.9) | 14 (4.1) | |
| Working/Studying time per day, No. (%)#2 | |||
| ≤ 6 h | 1043 (16.0) | 12 (3.5) | < 0.001* |
| 6–8 h | 3554 (54.7) | 130 (38.6) | |
| 8–10 h | 1225 (18.9) | 103 (30.6) | |
| > 10 h | 673 (10.4) | 92 (27.3) | |
| Continuous working/studying time per day, No. (%)#2 | |||
| ≤ 1 h | 1116 (17.2) | 23 (6.8) | < 0.001* |
| 1–2 h | 2654 (40.8) | 123 (36.5) | |
| 2–3 h | 1713 (26.4) | 96 (28.5) | |
| > 3 h | 1012 (15.6) | 95 (28.2) | |
| Screen time per day, No. (%)#2 | |||
| ≤ 0.5 h | 1689 (26.0) | 44 (13.1) | < 0.001* |
| 0.5–1 h | 2565 (39.5) | 118 (35.0) | |
| 1–2 h | 1445 (22.2) | 115 (34.1) | |
| > 2 h | 796 (12.3) | 60 (17.8) | |
#1: Data was analyzed using non-parametric test
#2: Data was analyzed using Chi-square test
#3: Bad writing habits include ①when reading or writing, the distance between the eyes and the table is less than 33 cm, ②when reading or writing, the distance of the chest from the table is less than the width of a punch, ③when writing, the distance between the hand and the tip of the pen is less than 3.3 cm, ④often tilt your head when reading or writing, ⑤often read or write on your stoma
#4: Participants included low/moderate myopia as well as non-myopia
*: P < 0.05