AIM: To investigate the prevalence and risk factors of pterygium in Zhuang and Miao nationality adults aged 40 and over in Wenshan prefecture, Yunnan Province.

METHODS: An epidemiological survey of Zhuang and Miao nationality in Yunnan Province was conducted by using the portable slit-lamp and Keratograph-D eye surface analyzer. The Logistic regression analysis was operated to determine the impact of gender, age, occupation, outdoor activities and nationality on pterygium.

RESULTS: Totally 1 239 participants were included from March to November 2019, 437 people had pterygium in one or both eyes, and the total prevalence was 35.27%. Pterygium of both eyes accounted for 59.27% while pterygium of single eye accounted for 40.73%. The prevalence of pterygium was 34.84%(224 people)in Zhuang population and 35.74%(213 people)in Miao population, there was no significant difference between the two groups(P=0.740). According to the result of Logistic regression analysis, opening of meibomian is the influencing factor of pterygium(P=0.019), with OR=1.348. Gender, age, education, outdoor activities, hypertension and eating habits were not the influencing factors of pterygium. Logistic regression was used to analyze the invasion degree of pterygium. The results showed that the height of lacrimal river was the influencing factor of pterygium(P=0.048). The lower the lacrimal river height, the greater the degree of invasion.

CONCLUSION: The prevalence of pterygium in Zhuang and Miao nationality aged 40 and over in Wenshan prefecture, Yunnan Province is high, with no significant difference between the two nationalities. The function of meibomian gland, the quality and quantity of tears are related to pterygium.