Table 3

Prevalence of cataract by persons with any eye or by total eyes with blindness (BL), severe visual impairment (SVI), moderate visual impairment (MVI) or early visual impairment (EVI)—best corrected visual acuity (BCVA) or pinhole among different groups of people in Tibetan Autonomous Prefecture of Kandze

Cataract BL BCVA <3/60Cataract SVI
BCVA>/=3/60 and <6/60
Cataract MVI
BCVA>/=6/60 and <6/18
Cataract EVI
BCVA>/=6/18 and <6/12
Persons with any eye
%
95% CI
Total eyes
%
95% CI
Persons with any eye
%
95% CI
Total eyes
%
95% CI
Persons with any eye
%
95% CI
Total eyes
%
95% CI
Persons with any eye
%
95% CI
Total eyes
%
95% CI
Ethnicity†
 Tibetan3.88 (3.33 to 4.51)*2.28 (1.98 to 2.62)*4.89 (4.28 to 5.60)**2.91 (2.57 to 3.29)**7.83 (7.05 to 8.69)**5.14 (4.68 to 5.63)*12.3 (11.3 to 13.3)*8.71 (8.12 to 9.34)
 Han1.82 (0.95 to 3.46)1.01 (0.54 to 1.87)2.22 (1.23 to 3.97)1.41 (0.84 to 2.37)4.44 (2.94 to 6.66)3.33 (2.38 to 4.65)8.89 (6.68 to 11.7)7.27 (5.81 to 9.07
 Other2.82 (1.06 to 7.29)1.41 (0.53 to 3.70)3.52 (1.47 to 8.21)1.76 (0.73 to 4.17)7.04 (3.82 to 12.6)4.23 (2.41 to 7.30)9.86 (5.91 to 16.0)7.39 (4.87 to 11.1)
Sex‡
 Male2.87 (2.24 to 3.69)1.61 (1.27 to 2.03)3.74 (3.00 to 4.64)2.11 (1.71 to 2.59)5.94 (5.00 to 7.04)3.76 (3.22 to 4.38)9.68 (8.48 to 11.0)6.73 (6.01 to 7.53)
 Female4.22 (3.52 to 5.05)*2.52 (2.13 to 2.98)**5.23 (4.45 to 6.14)*3.19 (2.75 to 3.70)**8.63 (7.62 to 9.75)***5.83 (5.23 to 6.49)***13.5 (12.3 to 14.9)***9.92 (9.15 to 10.7)***
Region§
 Pastoral area4.98 (3.84 to 6.43)2.90 (2.27 to 3.68)6.43 (5.12 to 8.03)3.71 (3.00 to 4.58)10.3 (8.66 to 12.3)6.52 (5.56 to 7.62)15.9 (13.9 to 18.2)11.2 (9.93 to 12.6)
 Agriculture area3.23 (2.69 to 3.87)**1.89 (1.59 to 2.24)**4.07 (3.46 to 4.78)**2.44 (2.10 to 2.83)**6.72 (5.93 to 7.60)***4.52 (4.05,5.04)***10.7 (9.71 to 11.8)***7.75 (7.14 to 8.40)***
 Urban3.20 (1.53 to 6.56)1.83 (0.92 to 3.61)3.20 (1.53 to 6.56)2.05 (1.07 to 3.90)4.57 (2.47 to 8.29)3.20 (1.90 to 5.33)**9.13 (5.96 to 13.7)7.31 (5.21 to 10.2)*
Distance from hospital, km¶
 ≤2001.91 (1.33 to 2.74)1.06 (0.75 to 1.49)2.44 (1.77 to 3.35)1.42 (1.05 to 1.91)4.69 (3.73 to 5.87)3.10 (2.54 to 3.78)8.12 (6.84 to 9.61)6.04 (5.24 to 6.95)
 201–4004.31 (3.38 to 5.50)2.54 (2.02 to 3.18)4.94 (3.93 to 6.19)2.96 (2.40 to 3.64)7.79 (6.52 to 9.30)5.08 (4.33 to 5.95)12.0 (10.4 to 13.8)8.59 (7.62 to 9.68)
 >4004.53 (3.66 to 5.59)2.68 (2.20 to 3.26)6.07 (5.06 to 7.27)3.61 (3.05 to 4.27)9.49 (8.23 to 10.9)6.32 (5.57 to 7.16)14.9 (13.3 to 16.6)10.5 (9.58 to 11.6)
P-trend <0.001<0.001<0.001<0.001<0.001<0.001<0.001<0.001
 Altitude of participants lived m¶
 ≤20002.10 (1.13 to 3.86)1.16 (0.64 to 2.07)2.73 (1.59 to 4.65)1.68 (1.03 to 2.73)4.41 (2.89 to 6.67)3.15 (2.21 to 4.47)8.19 (6.04 to 11.0)6.51 (5.11 to 8.27)
 2001–30002.55 (1.84 to 3.54)1.46 (1.07 to 1.98)3.28 (2.46 to 4.37)1.86 (1.42 to 2.44)5.40 (4.32 to 6.73)3.65 (3.01 to 4.42)9.34 (7.91 to 11.0)6.71 (5.83 to 7.71)
 3001–40004.21 (3.48 to 5.08)2.43 (2.03 to 2.90)5.31 (4.49 to 6.27)3.17 (2.71 to 3.69)8.37 (7.34 to 9.54)5.54 (4.93 to 6.21)13.0 (11.7 to 14.3)9.27 (8.49 to 10.1)
 >40005.33 (3.63 to 7.77)3.41 (2.42 to 4.79)6.40 (4.51 to 9.01)3.94 (2.87 to 5.40)11.7 (9.11 to 15.0)7.25 (5.75 to 9.10)17.1 (13.9 to 20.7)11.9 (10.0 to 14.2)
P-trend <0.001<0.001<0.001<0.001<0.001<0.001<0.001<0.001
Total3.63 (3.12 to 4.20)2.12 (1.85 to 2.43)4.58 (4.00 to 5.21)2.72 (2.40 to 3.06)7.45 (6.72 to 8.23)4.92 (4.50 to 5.38)11.8 (10.9 to 12.8)8.52 (7.97 to 9.10)
  • * P<0.05, **p<0.01, ***p<0.001.

  • † The prevalence of cataract among Tibetan and other ethnicities was compared with that among Han Chinese.

  • ‡ The prevalence of cataract was compared between male and female.

  • §The prevalence of cataract in agriculture area and urban was compared with that in pastoral area.

  • ¶The trend test on the prevalence of cataract with different grades of visual acuity across levels of distance from hospital and altitude was performed.