Prevalence and causes of visual impairment among schoolchildren in Mekelle, Ethiopia

Figures & data

Table 1. Characteristics of study sample

Characteristic	N (%)
Age in years
10–11	76 (6.7%)
12–13	807(22.3%)
14–15	254 (22.3%)
Total	Total:1137
Mean age (95% CI)	13 (CI: 11–15)
Sex
Male	506 (44.5%)
Female	631 (55.5%)
Grade
Grade 7	592(52)
Grade 8	545 (48)
Visual Impairment (VI)
Total Bilateral VI (VA<0.3 in better eye)	76 (6.7)
WHO VI Categories:
(Moderate VI:<0.3 ≥ 1.0)	44 (3.9)
(Severe VI: <1.0 ≥ 2.0)	17 (1.5)
(Blind:<2.0)	15 (1.3)
Total unilateral VI (VA<0.3 in one eye	65 (5.7)
Total VI <0.3 in at least one eye (‘failed’ screening)	141 (12.4)

Table 2. Prevalence of presenting visual impairment (VI) by sex

	Bilateral VI (VA<0.3 in better eye)		Unilateral VI (VA<0.3 in one eye)		VI at least one eye (total number failing screening)
	N	% (95% CI)	N	% (95% CI)	N	% (95% CI)
Total	76	6.7(5.2–8.1)	65	5.7(4.4–7.2)	141	12.4(10.5–14.3)
Boys	27	2.4(1.5–3.3)	24	2.1(1.3–2.9)	51	10.1% (7.5–12.3)
Girls	49	4.3(3.1–5.5)	41	3.6 (2.5–4.7)	90	14.3 (11.6–17.0)

*p-value for difference between males and females = 0.02

Table 3. Percentage and all causes of bilateral and unilateral vision impairment (VA<0.3)

Cause	Bilateral VI (n = 76)	Unilateral VI (n = 65)	Total with VI in one/both eyes (n = 141)
Uncorrected refractive error	66 (87%)	60 (92%)	126 (89%)
Conjunctivitis Trachoma, Vitamin A deficiency, Trachoma	10 (13%)	0 (0%)	10 (7%)
Amblyopia, Corneal Opacity, Trauma	0 (0%)	5 (8)%	5 (4%)