1.29-1.88) were significantly associated with correctable visual impairment. A higher level

Although correctable visual impairment HA15 gained more lines of improvement than uncorrectable visual impairment, 35.29 of uncorrectable SVI and 18.22 of uncorrectable Mod VI could gain four lines of improvement after refractive correction. Among 572 participants (12.59 ) who had mild visual impairment according to the aforementioned definition with a presenting visual acuity worse than 20/40 in the better eye, only 88 subjects (15.38 ) had no improvement after correction, while 12.76 (95 CI, 10.03 to 15.50 ) could experience a four line improvement by wearing proper spectacles. In addition, 46.46 of Mod VI (95 CI, 41.44 to 51.56 ) and 45.00 of SVI (95 CI, 23.00 to 69.00 ) obtained an improvement of at least four lines with accurately prescribed spectacles. Although correctable visual impairment gained more lines of improvement than uncorrectable visual impairment, 35.29 of uncorrectable SVI and 18.22 of uncorrectable Mod VI could gain four lines of improvement after refractive correction. Of the 4545 participants, 1129 participants title= fpsyg.2015.00360 gained an improvement of two or more lines in visual acuity. Thus,Zhu et al. BMC Public Health 2013, 13:311 http://www.biomedcentral.com/1471-2458/13/Page 7 ofTable 3 Univariate and multivariate analysis of visual impairment and correctable visual impairment for a 6/12 cutoffCharacteristic No VI n Age,y 60-69 70-79 80 Gender Male Female Type of insurance No insurance Urban insurance Others Occupation Peasant Non-peasant Level of education Illiteracy Primary school 417 253 1825 480 1.00(reference) 0.43***(0.36-0.52) 0.31***(0.25-0.38) 1.00(reference) 0.74**(0.60-0.93) 0.55***(0.42-0.71) 128 304 167 1.00(reference) 0.54***(0.43-0.69) 0.42***(0.33-0.54) 1.00(reference) 0.81(0.62-1.06) 0.65**(0.48-0.89) 973 245 2560 728 0.89(0.75-1.04) 1.00(reference) 0.73***(0.60-0.89) 1.00(reference) 156 443 0.93(0.76-1.13) 1.00(reference) 0.80(0.64-1.01) 1.00(reference) 16 4 1.00(reference) 1.15(0.38-3.46) 1.05(0.35-3.17) 1.00(reference) 1.24(0.38-4.06) 1.02(0.31-3.34) 3 306 290 1.00(reference) 0.93(0.27-3.22) 0.88(0.25-3.02) 1.00(reference) 1.02(0.28-3.72) 0.88(0.24-3.21) 1574 319 1959 654 1.00(reference) 1.65***(1.42-1.91) 1.00(reference) 1.67***(1.42-1.97) 207 392 1.00(reference) 1.52***(1.27-1.82) 1.00(reference) 1.56***(1.29-1.88) 2523 370 777 319 233 284 1.00(reference) 2.80***(2.36-3.32) 8.31***(6.77-10.20) 1.00(reference) 2.62***(2.19-3.13) 7.48***(6.00-9.33) 274 196 129 1.00(reference) 2.32***(1.90-2.84) 5.10***(3.98-6.54) 1.00(reference) 2.24***(1.82-2.76) 4.80***(3.69-6.26) n VI Univariate odds ratio (95 CI) Multivariate odds ratio (95 CI) n Correctable VI Univariate odds ratio (95 CI) Multivariate odds ratio (95 CI)1749 503 1768Secondary school or 1291 240 higherCI=confidence interval.