The prevalence of glaucoma in adult rural Chinese populations of the Bai nationality in Dali: the Yunnan Minority Eye Study

Abstract

Purpose: We evaluated the prevalence of glaucoma in adults of the Bai Nationality populations in rural China.

Methods: A population-based survey of Chinese Bai Nationality aged ≥50 years from randomly selected block groups in southwestern China was conducted. Eligible persons were invited to local examination sites for a complete ophthalmic examination. Glaucoma was diagnosed using the International Society of Geographical and Epidemiological Ophthalmology Classification scheme.

Results: In the study, 2133 subjects (77.8% participation rate) were examined, with a crude prevalence of all glaucoma of 2.2% (95% confidence interval [CI] 1.6%-2.9%). Primary open angle glaucoma (POAG) was found in 1.0% of cases (95% CI 0.6%-1.6%) and primary angle-closure glaucoma (PACG) in 0.9% (95% CI 0.6%-1.4%). The prevalence of all glaucoma was significantly higher in older people and women. Mean intraocular pressure (IOP) was 16.17 ± 3.74 mm Hg (97.5th and 99.5th percentiles, 24 mm Hg and 30 mm Hg, respectively). The mean vertical cup-to-disc ratio (VCDR) was 0.43 ± 0.17 (97.5th and 99.5th percentiles 0.7 and 0.8, respectively). Unilateral blindness was found in 80% of PACG, compared to only 36.3% of POAG cases.

Conclusions: Prevalence of POAG is similar to PACG in the ethnic Bai population living in rural southwestern China. PACG has a worse visual impairment and prognosis compared to POAG.