Blindness, low vision and cataract surgery outcome among adults in Hohhot of Inner Mongolia: a Rapid Assessment of Avoidable Blindness (RAAB) study.

BACKGROUND: To determine the prevalence and causes of visual impairment (VI), and to describe the characteristics of cataract surgery coverage and related barriers among adults aged ≥50 years residing in Hohhot, Inner Mongolia.

METHODS: A population-based cross-sectional study was performed. Presenting visual acuity (PVA) was measured using the Rapid Assessment of Avoidable Blindness (RAAB) methodology. All VI cases were defined using the WHO definition, based on the PVA of the better-seeing eye. Details on history of cataract surgery and barriers to cataract surgery were also obtained using a standardised questionnaire.

RESULTS: Of 4500 eligible individuals, 3985 (88.6% response rate) were examined. The age-standardised prevalence of moderate VI (PVA <6/18 to ≥6/60) was 5.4% (95% CI 4.6% to 6.3%), and severe VI (PVA <6/60 to ≥3/60) was 0.9% (95% CI 0.6% to 1.3%). The age-standardised prevalence of blindness (PVA <3/60) was 1.2% (95% CI 0.8% to 1.6%). Uncorrected refractive error (40.1%) and cataract (37.9%) were the leading causes of overall VI. Cataract (34.9%) was the leading cause of blindness. Among individuals with blindness, cataract surgical coverage was 80.7%. Among individuals with blindness due to cataract, the main barriers to cataract surgery were lack of awareness (38.1%).

CONCLUSIONS: The age-standardised prevalence rate of blindness in Hohhot was lower compared with other RAAB studies in China. Cataract was the leading cause of blindness. These findings provide useful information for the planning of public healthcare services in Inner Mongolia.