Table 3.

Prevalence of Visual Impairment with Refractive Error (One or Both Eyes) by Age, Grade, and Gender

Children Age (yrs)‡	Children with Visual Impairment			Children Without Visual Impairment No. (%)	Total No. Examined
	Hyperopia No. (%; 95% CI)*	Myopia No. (%; 95% CI)†	Emmetropia No. (%)
10	4 (0.99; 0.27–2.51)	44 (10.9; 7.00–14.7)	11 (2.7)	346 (85.4)	405
11	5 (0.82; 0.27–1.91)	84 (13.8; 10.5–17.2)	20 (3.3)	498 (82.0)	607
12	5 (0.58; 0.19–1.34)	143 (16.5; 13.2–19.8)	23 (2.6)	697 (80.3)	868
13	12 (1.21; 0.63–2.12)	191 (19.4; 16.7–22.1)	32 (3.2)	750 (76.1)	985
14	3 (0.34; 0.07–1.00)	205 (23.3; 20.0–26.7)	16 (1.8)	654 (74.5)	878
15	3 (0.56; 0.11–1.62)	147 (27.3; 22.6–32.0)	10 (1.9)	379 (70.3)	539
Gender
Male	20 (0.88; 0.54–1.35)	383 (16.8; 14.9–18.7)	53 (2.3)	1822 (80.0)	2278
Female	12 (0.60; 0.31–1.04)	431 (21.5; 19.0–24.0)	59 (2.9)	1502 (75.0)	2004
Grade
5th	6 (0.72; 0.27–1.56)	79 (9.50; 6.94–12.1)	22 (2.6)	725 (87.1)	832
6th	7 (0.86; 0.35–1.77)	133 (16.4; 12.6–20.3)	24 (3.0)	646 (79.8)	810
7th	2 (0.23; 0.03–0.84)	168 (19.5; 15.0–24.1)	27 (3.1)	663 (77.1)	860
8th	9 (0.99; 0.45–1.87)	200 (22.0; 17.4–26.7)	27 (3.0)	672 (74.0)	908
9th	8 (0.92; 0.40–1.80)	234 (26.8; 23.4–30.3)	12 (1.4)	618 (70.9)	872
All	32 (0.74; 0.51–1.05)	814 (19.0; 17.8–20.2)	112 (2.6)	3324 (77.6)	4282

^*Confidence intervals for all hyperopia estimates were calculated using an exact binomial distribution instead of the normal approximation with adjustments for sampling design effects, which ranged from 0.710 to 1.090.

^†Design effects were taken into account in the calculation of confidence intervals for myopia estimates based on the normal approximation. Design effects ranged from 1.201 to 1.765 for age-specific estimates, 1.522 and 1.917 for gender-specific estimates, and 1.375 to 2.943 for grade-specific estimates.

^‡Twenty-five children of age 9 were grouped with age 10, and 78 children of age 16 were grouped with age 15.