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Blindness, low vision and cataract surgery outcome among adults in Hohhot of Inner Mongolia: a Rapid Assessment of Avoidable Blindness (RAAB) study
  1. Guisen Zhang1,
  2. Yih-Chung Tham2,
  3. Hui Gong1,
  4. Fengmei Ren1,
  5. Jilitu Morige1,
  6. Wei Dai2,
  7. Ching-Yu Cheng2,
  8. Han Zhang3,
  9. Lei Liu3
  1. 1 Department of Ophthalmology, Hohhot Chao Ju Eye Hospital, Hohhot, China
  2. 2 Singapore National Eye Center, Singapore Eye Research Institute, Singapore
  3. 3 Department of Ophthalmology, The First Affiliated Hospital, China Medical University, Shenyang, China
  1. Correspondence to Dr Han Zhang and Dr Lei Liu, Department of Ophthalmology, The First Affiliated Hospital, China Medical University, Shenyang 110001, China; zhanghan0614{at}, liuleijiao{at}


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.

  • visual impairment
  • blindness
  • cataract
  • low vision
  • population

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  • HZ and LL contributed equally.

  • Contributors GZ designed the study protocols. HG, FR and JM performed the data collection and input. LL, Y-CT and C-YC drafted the paper. WD, HZ and LL guided and amended the paper writing. GZ was the study team trainer and commented on the draft paper.

  • Funding The study was supported by the National Natural Science Foundation of China (no. 81300783), Liaoning Science and Technology Project (no. 2013225303) and Liaoning Provincial Department of Education (no. LQNK201703).

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval Chao Ju Eye Hospital Research Proposal.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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