Purpose To describe the prevalence and risk factors of primary angle-closure glaucoma (PACG) and to explore nationality difference in Chinese.

Methods The Yunnan Minority Eye Study was conducted in a rural multiethnic area in Yunnan province and included 6546 participants aged over 50 years. PACG was diagnosed based on International Society of Geographical and Epidemiologic Ophthalmology criteria by experienced ophthalmologists. Multivariate regression modelling was conducted to examine risk factors for PACG. Principal component analyis (PCA) was performed to evaluate the effects of ethnicity on PACG.

Results The overall prevalence of PACG was 0.7% (95% CIs: 0.5% to 0.9%). PCA indicated that ethnicity is significantly related to the presence of PACG (p<0.001) after controlling for other risk factors. In addition, higher PACG prevalence was also correlated with older age (60–69 years group (OR: 3.47; 95% CI: 1.11 to 10.84; p<0.05) and 70–79 years group (OR: 4.71; 95% CI: 1.40 to 15.86; p<0.05) as compared with 50–59 years group), higher intraocular pressures (OR: 1.26; 95% CI: 1.17 to 1.36; p<0.001), shorter axial lengths (OR: 0.42; 95% CI: 0.32 to 0.56; p<0.001) and thinner central corneal thicknesses (OR: 0.89; 95% CI: 0.81 to 0.99; p<0.05).

Conclusions This multiethnic study on Chinese adults living in the same geographical location indicated that ethnicity is a significant risk factor for PACG. However, there were still some of the effects of ethnic differences on the prevalence of PACG that could not be explained and further studies should take culture and lifestyle factors into account.