The Prevalence of Blindness, Visual Impairment and Cataract Surgery in Tuoketuo and Shangdu Counties, Inner Mongolia, China

Aim: A population-based survey was conducted in Tuoketuo and Shangdu Counties in Inner Mongolia Autonomous Region, China, in the Autumn of 2010, to assess the prevalence and causes of blindness and visual impairment of people aged 50 years and over. Methods: Random cluster sampling was used to select 82 clusters of 50 residents in the 2 counties. Each survey team included an ophthalmologist, a nurse and a coordinator, who went to door to door in each cluster to identify eligible people. A torch, direct ophthalmoscope and portable slit lamp were used for eye examination. Visual acuity (VA) was tested for each eye of every subject. Those with VA below 6/18 in either eye were examined and causes identified. Results: The survey identified a prevalence of blindness in people aged 50+ in Tuoketuo of 1.2% (95% Confidence Interval: 0.7% 1.7%) and in Shangdu of 1.4% (95% CI: 1.0% 1.9%). Cataract was identified as the leading cause of blindness (BL) and severe visual impairment (SVI), and uncorrected refractive errors were the major causes of moderate visual impairment (MVI) in both counties. Over two thirds of blindness, SVI and MVI were identified as avoidable. Conclusions: The prevalence of blindness in people aged 50+ in Tuoketuo and Shangdu was low compared to other studies conducted in China [1] [2]. The prevalence of blindness of people aged 50 years and over could be reduced by up to two thirds Corresponding author.