Demographic characteristics of participants and usage of electronic devices before the pandemic (N=2476)
| Demographic characteristics | N (%) |
| Mean age (years) ±SD | 15.52±1.66 (range 10–19) |
| Female | 1606 (64.9) |
| Grade | |
| 4–6 | 11 (0.4) |
| 7–9 | 781 (31.6) |
| 10–12 | 1684 (68) |
| Refractive status | |
| Emmetropia | 1180 (47.7) |
| Myopia | 1055 (42.6) |
| Hyperopia | 241 (9.7) |
| Glasses and contact lens (CL) use | |
| None | 1180 (47.7) |
| Glasses for myopia | 784 (31.7) |
| Glasses for hyperopia | 186 (7.5) |
| CL for myopia | 151 (6.1) |
| CL for hyperopia | 47 (1.9) |
| Glasses and CL for myopia | 120 (4.8) |
| Glasses and CL for hyperopia | 8 (0.3) |
| Most commonly used digital devices (pre-COVID-19) | |
| Mobile phone | 1341 (54.2) |
| Tablet | 454 (18.3) |
| Computer desktop | 436 (17.6) |
| Computer laptop | 216 (8.7) |
| Television | 29 (1.2) |
| Frequency of eye check-up | |
| None | 1054 (42.6) |
| Once every 2 years | 504 (20.4) |
| Once a year | 715 (28.9) |
| Twice a year | 203 (8.2) |