Visual acuity among schoolchildren aged 6–15 years in the NS4 cohort
| Mild vision impairment, 20/40>VA≥20/70 n (%) | Moderate vision impairment, 20/70>VA≥20/200 n (%) | Severe vision impairment, 20/200>VA≥20/400 n (%) | Total vision impairment, 20/40>VA≥20/400 n (%) | Blindness, VA<20/400 n (%) | |
| All children | |||||
| Monocular (other eye normal) | 180 (3) | 76 (1.3) | 5 (0.1) | 261 (4.4) | 2 (0.03) |
| Binocular (worst eye) | 124 (2.1) | 181 (3.1) | 6 (0.1) | 312 (5.3) | 1 (0.02) |
| In at least one eye | 367 (6.2) | 261 (4.4) | 11 (0.2) | 573 (9.7) | 3 (0.05) |
| Subgroup analyses (in at least one eye) | |||||
| Gender | |||||
| Female | 194 (6.7) | 144 (5) | 5 (0.2) | 312 (10.8) | 1 (0.02) |
| Male | 172 (5.6) | 117 (3.9) | 6 (0.2) | 261 (8.5) | 2 (0.08) |
| Age group (years) | |||||
| 6–10 | 127 (3.8) | 90 (2.7) | 2 (0.1) | 194 (5.8) | 0 (0) |
| 11–15 | 239 (9.2) | 171 (6.6) | 9 (0.4) | 379 (14.5) | 3 (0.05) |
| Geographical region | |||||
| Yerevan | 152 (8) | 102 (5.4) | 4 (0.2) | 230 (12.1) | 1 (0.05) |
| Other urban areas | 121 (6.5) | 75 (4) | 5 (0.3) | 180 (12.4) | 1 (0.04) |
| Rural areas | 93 (4.3) | 84 (3.9) | 2 (0.1) | 163 (7.5) | 1 (0.06) |
NS4, Nationwide School Sight Sampling Survey; VA, visual acuity.