Prevalence and pattern of refractive error and visual impairment among schoolchildren: the Lhasa childhood eye study

Table 1 Distribution of Uncorrected and Best-Corrected Visual Acuity

	Uncorrected Visual Acuity			Wearing glasses		Presenting Visual Acuity			Best corrected Visual Acuity
Visual Acuity Category	n	%	95%CI	n	%	n	%	95%CI	n	%	95%CI
Normal/near normal	1450	78.2	76.33–80.09	6	0.3	1454	78.4	76.55–80.30	1735	93.6	92.47–94.70
Unilateral impairment	177	9.5	8.21–10.88	6	0.3	183	9.9	8.51–11.23	69	3.7	2.86–4.58
Mild impairment in better eye	205	11.1	9.63–12.48	3	0.2	198	10.7	9.27–12.90	46	2.5	1.77–3.19
Moderate impairment in better eye	20	1.1	0.61–1.55	1	0.1	17	0.9	0.48–1.35	3	0.2	0.00–0.34
Blind in both eyes	2	0.1	0.00–0.26	0	0	2	0.1	0.00–0.26	1	0.0	0.00–0.16
All	1854	100		16	0.9	1854	100		1854	100

CI confidence interval
Normal/near normal means log MAR visual acuity ≤0.2 in both eyes
Unilateral visual impairment means log MAR visual acuity ≤0.2 in one eye only
Mild visual impairment means log MAR visual acuity 0.3–0.5 in the better eye
Moderate visual impairment means log MAR visual acuity 0.6–0.9 in the better eye
Blindness means log MAR visual acuity ≥1.0 in the better eye

ISSN: 1471-2415