Prevalence and associations of refractive error in indigenous Australians within central Australia: the central Australian ocular health study

Purpose: To determine the prevalence and associations of refractive error within the indigenous Australian population 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. This equated to 36% of those aged 20 years or older and 67% of those aged 40 years or older within this district. Participants were recruited as they presented to the eye clinic at each remote community. Participants underwent subjective refraction to determine spherical equivalent and then had a slit-lamp anterior segment examination. Participants were only included if they were phakic and only the right eye was considered. The prevalence of hypermetropia worse than +1.0 dioptres (D), myopia worse than -0.5 D and astigmatism worse than 1.0 D is presented. Results: From those recruited, 15.2% were hypermetropic; 11.1% were myopic; and 6.2% had astigmatism. Participants became progressively more hypermetropic with increasing age until the age of 70 years, after which time they become more myopic. Furthermore, there was an increasing likelihood of myopia and a decreasing likelihood of hypermetropia with increasing nuclear opalescent cataract. Conclusion: Our study has shown that indigenous Australians are less likely to be ametropic compared with non-indigenous groups. Variations with age and nuclear opalescent cataract seen in other previous work have also been observed in our sample.