Table 4 Prevalence (95% CI) of myopia, hyperopia, and astigmatism, according to cycloplegic refraction, among primary and middle school students and their distribution in groups of age, gender and area of residence*.
| Number | Myopia | Hyperopia | Astigmatism | |
|---|---|---|---|---|
| Age (years) | ||||
| 7 | 366 | 2.5 (0.7–4.4) | 28.9 (22.6–35.2) | 20.9 (15.5–26.3) |
| 8 | 398 | 2.6 (0.1–5.0) | 22.7 (16.4–28.9) | 20.1 (13.3–26.9) |
| 9 | 348 | 2.6 (0.6–4.7) | 16.7 (12.0–21.4) | 20.4 (14.7–26.0) |
| 10 | 439 | 2.4 (0.5–4.3) | 12.4 (7.9–17.0) | 18.6 (14.0–23.3) |
| 11 | 489 | 4.0 (1.9–6.1) | 12.9 (8.3–17.5) | 19.8 (16.2–23.4) |
| 12 | 459 | 3.5 (1.9–5.2) | 16.9 (12.3–21.5) | 16.9 (11.6–22.2) |
| 13 | 502 | 3.8 (2.2–5.3) | 14.1 (10.6–17.6) | 16.4 (12.3–20.6) |
| 14 | 308 | 5.1 (1.8–8.3) | 13.0 (9.8–16.1) | 18.0 (11.7–24.2) |
| 15 | 120 | 4.9 (0.8–9.0) | 10.3 (1.5–19.1) | 20.2 (12.8–27.6) |
| Gender | ||||
| Male | 1604 | 3.1 (1.9–4.3) | 16.1 (11.0–21.1) | 18.5 (15.5–21.5) |
| Female | 1886 | 3.7 (2.3–5.2) | 17.3 (14.3–20.4) | 18.9 (14.6–23.2) |
| Area of residence | ||||
| Urban | 2341 | 3.7 (2.7–4.7) | 13.8 (10.9–16.8) | 21.0 (18.5–23.5) |
| Rural | 1149 | 2.9 (1.1–4.8) | 21.4 (16.8–25.9) | 14.8 (10.6–19.0) |
| Total | 3490 | 3.4 (2.5–4.4) | 16.6 (13.6–19.7) | 18.7 (16.1–21.2) |
* Percentage (95% CI) standardised for age and grade level.
The design effect was 0.84 to 5.7.