Rapid assessment of avoidable blindness in three counties, Jiangxi Province, China

Background

A survey was undertaken in 2007 to assess the prevalence and causes of blindness and visual impairment in people aged ≥50 years in three different counties in Jiangxi, South East China (Gao9an, Xin9gan and Wan9zai). The counties were purposively selected to assess the impact of established non-governmental organisation activities in two counties (Gao9an and Xin9gan) compared with a third county (Wan9zai) without such a programme.

Methods

Clusters of 50 people aged ≥50 years were sampled with a probability proportional to the size of the population. Because of differences in expected prevalence and resources available for conducting the surveys, the total sample size varied from 4699 in Gao9an (94.0% response rate) to 3834 in Xin9gan (95.9%) and 2861 (95.4%) in Wan9zai. Households within clusters were selected through random walk sampling. Visual acuity (VA) was measured with a tumbling 'E' chart. Ophthalmologists examined people with VA<6/18 in either eye.

Results

The prevalence of blindness (VA<3/60 in the better eye with available correction) was similar in Gao9an (1.5%, 95% CI 1.1% to 1.8%), Xin9gan (1.8%, 1.4% to 2.2%) and Wan9zai (1.6%, 1.2% to 2.1%), and the prevalence of visual impairment (VA<6/18 and ≥6/60) was approximately fourfold higher. Cataract was the leading cause of blindness in each of the three counties, while uncorrected refractive error was the dominant cause of visual impairment. The majority of blindness was avoidable in Gao9an (84.3%), Xin9gan (71.0%) and Wan9zai (71.7%).

Conclusions

The prevalence of blindness in the three counties in Jiangxi, China was lower than expected, yet most of the blindness and visual impairment was avoidable, indicating that the prevalence could be reduced further through adequate programme planning and implementation.