Table 1.
General Characteristics of Population of Study
| Variables | Overall | Men | Women | p |
|---|---|---|---|---|
| (n=844) | (n=301) | (n=543) | ||
| Age (years) | 21.8 ± 3.3 | 22.2 ± 4.0 | 21.6 ± 2.9 | 0.005 |
| Frequency of alcohol intake | ||||
| Each year | 63 (7.46%) | 26 (8.64%) | 37 (6.81%) | 0.002 |
| Each month | 99 (11.7%) | 47 (15.6%) | 52 (9.58%) | |
| Every week | 69 (8.18%) | 29 (9.63%) | 40 (7.37%) | |
| No alcohol consumption | 613 (72.6%) | 199 (66.1%) | 414 (76.2%) | |
| Frequency of smoking | ||||
| Each month | 25 (2.96%) | 12 (3.99%) | 13 (2.39%) | 0.056 |
| Every week | 6 (0.71%) | 5 (1.66%) | 1 (0.18%) | |
| Every day | 1 (0.12%) | 0 (0.00%) | 1 (0.18%) | |
| Non-smoker | 812 (96.2%) | 284 (94.4%) | 528 (97.2%) | |
| Screen exposure time per day | ||||
| <3 h | 17 (2.0) | 10 (3.3) | 7 (1.3) | 0.022 |
| 3–6 h | 264 (31.3) | 105 (34.9) | 159 (29.3) | |
| >6 h | 563 (66.7) | 186 (61.8) | 377 (69.4) | |
| Intermittent Internet rest | ||||
| <3h | 535 (63.4%) | 201 (66.8%) | 334 (61.5%) | 0.197 |
| 3–5h | 111 (13.2%) | 38 (12.6%) | 73 (13.4%) | |
| >5h | 19 (2.25%) | 6 (1.99%) | 13 (2.39%) | |
| No rest | 179 (21.2%) | 56 (18.6%) | 123 (22.7%) | |
| Use of blue-light blocking spectacle lenses | ||||
| Yes | 433 (51.3) | 140 (46.5) | 293 (54.0) | 0.045 |
| No | 411 (48.7) | 161 (53.5) | 250 (46.0) | |
| Use of screen light filter | ||||
| Yes | 275 (32.6) | 107 (35.5) | 168 (30.9) | 0.196 |
| No | 569 (67.4) | 194 (64.5) | 375 (69.1) | |
| Display brightness | ||||
| Dull | 67 (7.9) | 18 (6.0) | 49 (9.0) | 0.068 |
| Very dull | 391 (46.3) | 130 (43.2) | 261 (48.1) | |
| Bright | 346 (41.0) | 134 (44.5) | 212 (39.0) | |
| Very bright | 40 (4.7) | 19 (6.3) | 21 (3.9) | |
| Display viewing distance | ||||
| < 40 cm | 480 (56.9) | 134 (44.5) | 346 (63.7) | <0.001 |
| 40–76 cm | 343 (40.6) | 159 (52.8) | 184 (33.9) | |
| >76 cm | 21 (2.5) | 8 (2.7) | 13 (2.4) | |
| Room lighting | ||||
| Dark | 17 (2.0) | 5 (1.7) | 12 (2.2) | 0.24 |
| Low light | 176 (20.9) | 71 (23.6) | 105 (19.3) | |
| Illuminated | 537 (63.6) | 192 (63.8) | 345 (63.5) | |
| Very illuminated | 114 (13.5) | 33 (11.0) | 81 (14.9) | |
| Most used device | ||||
| Phone | 446 (52.8%) | 154 (51.2%) | 292 (53.8%) | 0.832 |
| PC or laptop | 387 (45.9%) | 143 (47.5%) | 244 (44.9%) | |
| Tablet | 10 (1.18%) | 4 (1.33%) | 6 (1.10%) | |
| Television | 1 (0.12%) | 0 (0.00%) | 1 (0.18%) | |
| PIU | ||||
| Controlled | 720 (85.3) | 248 (82.4) | 472 (86.9) | 0.093 |
| Uncontrolled | 124 (14.7) | 53 (17.6) | 71 (13.1) | |
| SDED | ||||
| Yes | 598 (70.9) | 201 (66.8) | 397 (73.1) | 0.063 |
| No | 246 (29.1) | 100 (33.2) | 146 (26.9) |
Note: Data shown as mean ± SD or absolute frequency (%).
Abbreviations: PIU, problematic internet use; SDED, symptomatic dry eye disease.