Table 3.

Sample prevalence of presenting (available correction) blindness and VI: SVI, MVI and EVI

	Blindness		Severe VI		Moderate VI		Early VI
	N	% (95% CI)	N	% (95% CI)	N	% (95% CI)	N	% (95% CI)
Ethnicity
Tibetan	89	2.16 (1.76 to 2.65)*	39	0.95 (0.69 to 1.29)	215	5.21 (4.57 to 5.93)	309	7.49 (6.72 to 8.33)
Han	3	0.61 (0.20 to 1.86)	5	1.01 (0.42 to 2.41)	21	4.24 (2.78 to 6.42)	34	6.87 (4.95,9.46)
Other	2	1.41 (0.35 to 5.48)	1	0.70 (0.10 to 4.86)	6	4.23 (1.90 to 9.11)	12	8.45 (4.85 to 14.3)
Sex
Male	35	1.68 (1.21 to 2.33)	18	0.86 (0.54 to 1.37)	104	4.98 (4.13 to 6.00)	127	6.09 (5.14 to 7.20)
Female	59	2.20 (1.71 to 2.83)	27	1.01 (0.69 to 1.47)	138	5.16 (4.38 to 6.06)	228	8.52 (7.52, 9.64)†
Region
Pastoral area	36	3.26 (2.36 to 4.48)	18	1.63 (1.03 to 2.57)	79	7.15 (5.77 to 8.83)	97	8.78 (7.25 to 10.6)
Agriculture area	54	1.57 (1.20 to 2.04)‡	25	0.73 (0.49, 1.07)‡	150	4.36 (3.73, 5.10)‡	241	7.01 (6.20 to 7.91)
Urban	4	1.83 (0.69 to 4.78)	2	0.91 (0.23 to 3.59)	13	5.94 (3.47 to 9.97)	17	7.76 (4.87 to 12.1)
Distance from hospital, km
≤200	13	0.86 (0.50 to 1.47)	8	0.53 (0.26 to 1.05)	70	4.62 (3.67 to 5.80)	119	7.85 (6.60 to 9.32)
201–400	34	2.37 (1.70 to 3.29)	15	1.04 (0.63 to 1.72)	61	4.24 (3.32 to 5.42)	103	7.17 (5.94 to 8.62)
>400	47	2.59 (1.95 to 3.44)	22	1.21 (0.80 to 1.84)	111	6.13 (5.11 to 7.33)	133	7.34 (6.23 to 8.64)
P trend		<0.001		0.046		0.052		0.618
Total	94	1.97 (1.60 to 2.41)	45	0.94 (0.69 to 1.26)	242	5.08 (4.47 to 5.74)	355	7.45 (6.72 to 8.23)

*The prevalence of blindness among Tibetan was significantly higher than that among Han Chinese with p=0.029.

†The prevalence of EVI among female was significantly higher than that among male with p=0.002.

‡The prevalence of blindness, SVI and MEVI in pastoral area were significantly higher than those in agriculture area with p=0.001, p=0.009 and p<0.001, respectively.

EVI, early VI; MVI, moderate VI; SVI, severe VI; VI, visual impairment.