Table 5 Prevalence (95% CI) of myopia, hyperopia, and astigmatism, according to non‐cycloplegic refraction, among high school students and their distribution in groups of age, gender and area of residence*.

	Number	Myopia	Hyperopia	Astigmatism
Age (years)
14	352	34.4 (27.0–41.8)	1.6 (0.4–2.8)	18.8 (15.9–21.7)
15	619	33.2 (28.4–38.1)	0.9 (0.2–3.5)†	17.3 (13.7–21.0)
16	505	32.6 (18.3–46.9)	3.2 (0.1–6.3)	16.9 (12.4–21.4)
17	271	30.4 (19.7–41.0)	3.4 (1.1–10.2)†	19.6 (15.5–23.7)
18	88	39.8 (24.7–55.0)	0.6 (0.1–4.0)†	20.7 (12.1–29.4)
Gender
Male	811	26.8 (21.0–32.6)	2.7 (0.8–4.6)	17.6 (16.4–18.7)
Female	1050	39.5 (33.7–45.3)	1.4 (0.5–2.4)	18.5 (12.0–24.9)
Area of residence
Urban	1361	33.7 (23.9–43.4)	2.3 (0.8–3.8)	18.3 (14.7–21.9)
Rural	500	29.4 (20.3–38.5)	0.9 (0.5–1.4)	16.3 (10.8–21.9)
Total	1861	33.0 (24.9–41.1)	2.1 (0.7–3.5)	18.0 (14.9–21.2)

*Percentage (95% CI) standardised for age and grade level.

†The 95% confidence interval was calculated using binominal distribution.

The design effect was 0.6 to 9.9.