Prevalence and causes of blindness and visual impairment among the elderly in rural southern Harbin, China.

PURPOSE

The purpose of this study was to estimate the prevalence and causes of visual impairment(VI) and blindness by a population-based survey in an elderly rural Chinese population.

METHODS

Cluster sampling was used to select samples. The protocol consisted of an interview, pilot study, visual acuity (VA) testing and a clinical examination. The definitions of blindness (VA < 20/400) and visual impairment (VA < 20/60 to > or = 20/400) were based on the presenting VA in the better eye. The major causes of VI and blindness were identified. The associations of bilateral VI and blindness by age, gender and education were calculated through multiple logistic regression. Cataract surgical coverage (CSC) was also calculated.

RESULTS

Among the 5559 people entered in the project, 5057 were examined (91.0%), and of these 2383(47.1%) were men. The mean age was 60.5 (range, 50-96) years old. The prevalence of bilateral blindness and VI was 1.9% (95% confidence interval (CI): 1.6 % to 2.3%) and 8.3%(95% CI: 7.5 % to 9.1%), respectively. We found that age, female gender, and illiteracy were associated with bilateral blindness. The leading cause of bilateral blindness was cataract (70.4%), followed by corneal opacity (8.2%) and glaucoma (5.1%). The main causes for bilateral VI were refractive error (35.9%) and cataract (35.7%). The average CSC was 9.3% (95%CI: 6.7% to 11.7%).

CONCLUSIONS

Cataract is the dominant cause of bilateral blindness and VI in people over 50 years old in rural southern Harbin. Specific prevention and VI rehabilitation programs should be developed for the elderly rural Chinese population.