[Prevalence of blindness and moderate and severe visual impairment among adults aged 50 years or above in Yangxi County of Guangdong Province: the China Nine-Province Survey].
OBJECTIVE
To investigate the prevalence of blindness and moderate and severe visual impairment among adults aged 50 years or above in Yangxi County of Guangdong Province, China.


METHODS
It was a population-based cross-section study.Geographically defined cluster sampling was used in randomly selecting 5 531 individuals aged 50 years or above in Yangxi County from September 2006 to January 2007. The survey was preceded by a pilot study where operational methods were refined and quality assurance evaluation was carried out. All participants were enumerated using village registers followed by door-to-door visits.Eligible individuals were invited to receive visual acuity measurement and eye examination.Statistical analyses were performed using Stata/SE Statistical Software, release 9.0. Chi-square test was used to investigate the association of age, gender and education with presenting and best corrected visual acuity.


RESULTS
Five thousands five hundreds and thirty-one individuals were enumerated and 4 589 persons were examined, the response rate was 82.97%. Based on the criteria of World Health Organization visual impairment classification in 1973, the prevalence of blindness and moderate and severe visual impairment defined as best corrected visual acuity was 2.38% (109/4 589) and 9.44% (433/4 589) respectively. The prevalence of blindness and moderate and severe visual impairment defined as presenting visual acuity was 2.68% (123/4 589) and 18.15% (833/4 589) respectively. The prevalence of blindness and moderate and severe visual impairment was higher in aged (trend χ(2) = 1 239.34, P < 0.01) , female (χ(2) = 37.88, P < 0.01) and illiterate (trend χ(2) = 235.11, P < 0.01) persons. Cataract was the first leading cause of blindness and visual impairment.


CONCLUSIONS
The prevalence of blindness and moderate and severe visual impairment is higher among older adults aged 50 years or above in Yangxi County. Cataract remains as the first leading cause of blindness and visual impairment.
Zhongshan Ophthalmic Center, Sun Yat-sen University,Guangzhou 510060, China.
Jian
J
Ge
Mingguang
M
He
Email: zhjialiang@163.com.
Jialiang
J
Zhao
Min
M
Fang
Leon B
LB
Ellwein
Ning
N
He
Mei
M
Yang
Yu
Y
Wang
Xuecheng
X
Gao
D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001766:Blindness / Q000453:epidemiology*; D002386:Cataract / Q000453:epidemiology; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D014786:Vision Disorders / Q000453:epidemiology*; D015354:Vision, Low / Q000453:epidemiology; D014792:Visual Acuity