Objectives To assess the prevalence of visual impairment (VI) and blindness (BL) due to cataract and cataract surgical outcomes in remote dispersed and high-altitude Tibetan areas of China.
Design and setting A cross-sectional study was conducted among people aged 50 and above in Tibetan Autonomous Prefecture of Kandze (TAPK), China, in 2017. The Rapid Assessment of Avoidable Blindness protocol was followed.
Participants Of 5000 eligible participants, 4764 were examined (response rate 95.3%).
Primary and secondary outcome measures Cataract VI was defined as lens opacity at visual acuity (VA) levels of <3/60 (Blindness (BL)), ≥3/60 and <6/60 (severe visual impairment (SVI)), ≥6/60 and <6/18 (moderate visual impairment (MVI)), ≥6/18 and <6/12 (early visual impairment (EVI)).
Results The estimated prevalence of cataract BL was 0.61% (95% CI 0.42 to 0.87). With best corrected VA, the estimated prevalence of SVI from cataract was 0.86% (95% CI 0.63 to 1.17); MVI was 2.39% (95% CI 2.00 to 2.87) and EVI was 5.21% (95% CI 4.61 to 5.87). Women in TAPK had a significantly higher prevalence of cataract BL (0.82%, 95% CI 0.54 to 2.15) than men (0.34%, 95% CI 0.16 to 0.70). Women had lower cataract surgical coverage (CSC) by eyes (60.8%, 95% CI 55.5 to 65.8) compared with men (70.1%; 95% CI 63.7 to 75.7). The prevalence of cataract BL was higher among Tibetan (2.28%; 95% CI 1.98 to 2.62) than Han Chinese (1.01%%; 95% CI 0.54% to 1.87%). Overall CSC by person with BL (by better eye) was 82.0% (95% CI 75.2 to 87.6). Among cataract-operated participants, 71.2% had VA equal to or better than 6/18.
Conclusions The study detected a low prevalence of VI and BL due to cataract with high CSC in the study area compared with many other places in China. Further actions should be taken to improve cataract surgical outcome.
- international health services
- cataract and refractive surgery
- public health
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Contributors BX: study design, training of the study teams, monitoring data collection and quality control, data cleaning, analysis as well as manuscript drafting and revision. DJ: draft of the manuscript, data analysis and critical revision of the manuscript. FJ, LL, HZ, DJ, JY, NY: data collection and valuable contribution to the study design. JY, WH: valuable contribution to the study design and revision of the manuscript. WH: statistical analysis and helpful revision of the manuscript. TB: valuable comments to the manuscript, revision of the manuscript critically for important intellectual content and English correction. JLYY: substantial contributions to the conception, designing and revision of the manuscript as well as analysis and interpretation of the data.
Funding The study is fully funded by Sichuan Provincial Health Bureau Research Fund, China (No.150063).
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval Ethical approval for this study was obtained from Zhongshan Ophthalmic Center, Sun Yat-sen University.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available in a public, open access repository.
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