Patterns and correlates of visual impairment and ocular hypertension among older adults in the general Chinese population: results from the CKB Biobank.

Background: While numerous ophthalmology-specific cohort studies have been conducted in China, there is a significant lack of comprehensive, population-based study on the potential determinants of visual impairment and ocular hypertension (OHT) in the general Chinese population.

Methods: In the 2020-2021 resurvey of the China Kadoorie Biobank study, ~25 000 randomly selected participants from 10 diverse localities (5 urban and 5 rural) were surveyed. Presenting visual acuity (PVA) was measured using the Random E eye chart and intraocular pressure (IOP) was measured using a handheld Icare (ic100) tonometer. Associations of sociodemographic and other factors with risks of visual impairment and OHT were examined using multivariable logistic regression.

Results: Among the 24 613 (aged 45-95 years, 64.4% women) participants, 21.8% had visual impairment (PVA <0.50) and 18.4% had OHT (IOP >18.6 mm Hg). The prevalence rate of visual impairment increased dramatically with age (49.3% in those ≥75 years vs 8.9% in those <55 years), but an opposite trend was observed for OHT. Risks of these two eye conditions were both inversely associated with household income and fish consumption but positively with systolic blood pressure and blood glucose. Higher education was associated with a higher OHT risk but not with visual impairment. Body mass index was inversely associated with visual impairment but positively with OHT. Age-related macular degeneration and glaucoma were most strongly associated with risk of visual impairment, followed by cataract.

Conclusion: The relatively high prevalence rates of poor vision and OHT in China suggest that well-targeted public health interventions should be developed.