Table 2. DD usage condition at 3 months by outcome groups.
| Variables/groups | Cured(n=10) | Improved(n=58) | Unchanged(n=67) | Worsened(n=21) | P value |
| Took breaktime when using DD (%) | |||||
| No | 1 (10) | 21 (39) | 26 (41) | 10 (50) | 0.19 |
| Yes | 9 (90) | 33 (61) | 37 (59) | 10 (50) | |
| Viewing distance 30 cm or more (%) | |||||
| No | 1 (10) | 9 (16) | 16 (25) | 8 (40) | 0.14 |
| Yes | 9 (90) | 46 (84) | 47 (75) | 12 (60) | |
| Adhering to the recommended time (%) | |||||
| No | 5 (50) | 29 (54) | 37 (61) | 13 (68) | 0.66 |
| Yes | 5 (50) | 25 (46) | 24 (39) | 6 (32) | |
| Successful DD time halving | |||||
| No | 3 (30) | 23 (40) | 32 (52) | 12 (63) | 0.21 |
| Yes | 7 (70) | 34 (60) | 30 (48) | 7 (37) | |
Data are presented as number of cases (%).
DD, hand-held digital devicesDD timethe amount of time spent using hand-held digital devices per day