AIM:To estimate the prevalence and related risk factors of pterygium among the middle-aged and the senile in the defined rural area of Heilongjiang.

METHODS:Population-based cross-sectional study. A total number of 6 196 subjects aged 50 years or older in 35 villages in Mingshui District of Heilongjiang was studied, using cluster random sampling methods. The prevalence of pterygium, distribution patterns and risk factors in this population were studied.

RESULTS:There were 5 669 subjects(91.49%)actually received the examination and 246 patients(329 eyes)were found among the population aged 50 years or older. The prevalence of pterygium was 4.34%. The prevalence of pterygium was positively correlated with age(for every 10a of age, OR=1.616,95%CI:1.372-1.903,P<0.01). Logistic regression analysis showed:non-glasses vs wearing glasses when been outdoors(OR=5.045,95%CI :1.592-15.985,P=0.006); outdoor workers vs indoor workers(OR=3.896,95%CI:2.834-5.356,P<0.01). Pterygium was related to the age, glass-wearing and times working outdoors.

CONCLUSION:In the alpine, rural area of Honglongjiang, the prevalence of pterygium is decreased. Old age and outdoor work are the risk factors, while wearing glasses when going out is a protective factor.