Prevalence and causes of corneal blindness

BACKGROUND: The study aimed to assess the prevalence and causes of corneal blindness in a rural northern Chinese population. DESIGN: Cross-sectional study. PARTICIPANTS OR SAMPLES: The cluster random sampling method was used to select the sample. METHODS: This population-based study included 11 787 participants of all ages in rural Heilongjiang Province, China. These participants underwent a detailed interview and eye examination that included the measurement of visual acuity, slit-lamp biomicroscopy and direct ophthalmoscopy. An eye was considered to have corneal blindness if the visual acuity was <9/18 because of corneal diseases. MAIN OUTCOME MEASURES: The main outcome measure was prevalence rates of corneal blindness and low vision. RESULTS: Among the 10 384 people enrolled in the study, the prevalence of corneal blindness is 0.3% (95% confidence interval 0.2-0.4%). The leading cause was keratitis in childhood (40.0%), followed by ocular trauma (33.3%) and keratitis in adulthood (20.0%). Age and illiteracy were found to be associated with an increased prevalence of corneal blindness. CONCLUSION: Blindness because of corneal diseases in rural areas of Northern China is a significant public health problem that needs to be given more attention.