Incidence of visual impairment and blindness in indigenous Australians within Central Australia: The Central Australian Ocular Health Study

Background: To estimate the incidence and causes of visual impairment and blindness among indigenous Australians living in Central Australia. Design: Clinic-based cohort study. Participants: A total of 1884 individuals aged ≥20years living in one of 30 remote communities within the statistical local area of 'Central Australia'. Methods: From those initially recruited, 608 (32%) participants were reviewed again between 6months and 3years (median 2years). Patients underwent Snellen visual acuity testing and subjective refraction. Following this, an assessment of their anterior and posterior segments was made. Baseline results were compared with those who were reviewed. Main Outcome Measures: The annual incidence rates and causes of bilateral visual impairment (vision worse than Snellen visual acuity 6/12 in the better eye) and bilateral blindness (Snellen visual acuity worse than 6/60 in the better eye). Results: The annual incidence of bilateral visual impairment and blindness was 6.82% (8.12% for those aged ≥40years) per year and 0.50% (0.62% for those aged ≥40years) per year, respectively. Refractive error, followed by cataract and diabetic retinopathy, were the main causes for incident bilateral visual impairment and blindness. Conclusion: This study has demonstrated rates of incident bilateral blindness and visual impairment among the indigenous Australian population within Central Australia, which are substantially higher than those from the non-indigenous population. Services need to address the underlying causes of this incident vision loss to reduce visual morbidity in indigenous Australians living in central Australia.