The prevalence and causes of visual impairment in indigenous Australians within central Australia: the Central Australian Ocular Health Study.

AIM: To determine the prevalence and causes of visual impairment and blindness among indigenous Australians living in central Australia.
METHODS: 1884 individuals aged 20 years or older, living in one of 30 remote communities within the statistical local area of "Central Australia", were recruited for this study, from which 1883 were assessable. This equated to 36% of those > or =20 years old and 67% of those > or =40 years old within this district. Participants were recruited as they presented to the eye clinic at each remote community. Patients underwent Snellen visual acuity testing and subjective refraction. After this, an assessment of their anterior and posterior segments was made. 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) were presented.
RESULTS: 19.4% (365/1883) had bilateral visual impairment (25.1% of those > or =40 years old) and 2.8% (53/1883) had bilateral blindness (3.6% of those > or =40 years old). Refractive error followed by cataract were the main causes for bilateral visual impairment and blindness. Following these, diabetic eye disease and trachomatous corneal opacification were the main causes of bilateral visual impairment and bilateral blindness, respectively.
CONCLUSION: This study indicates that bilateral visual impairment and blindness are, respectively, 25.1% and 3.6% among indigenous Australians, four to seven times higher than among the non-indigenous Australian population. Trachoma is the leading cause of bilateral blindness after refractive error and cataract.