Glaucoma prevalence in Indigenous Australians

Aim: Define the prevalence of glaucoma within the Indigenous Australian population. Methods: Aboriginal and Torres Strait Islander adults aged ≥40 years were recruited from 30 randomly selected sample areas or communities. Participants were regarded to have glaucoma if they had a cup:disc ratio (CDR) of >0.8, or missed ≥2 points on the Frequency Doubling Test and a CDR >0.7 in at least one eye. Results: 1189 eligible adult participants were examined, representing 72% of the target population. After excluding cases with missing or ungradable information, the authors found a 2.2% (95% CI 1.6% to 3.6%) overall prevalence of glaucoma. In univariate analyses, the odds of glaucoma increased with age (χ² trend=4.38, p<0.001), male gender (OR 2.43, 95% CI 1.10 to 5.41), less than secondary education (OR 4.74, 95% CI 1.96 to 11.45) and self-reported history of glaucoma (OR 20.8; 95% CI 6.23 to 69.51). After a multivariate analysis, none of these attributes other than history of glaucoma remained significant. No cases of low vision (presenting visual acuity (VA) <6/12 to ≤6/60) or blindness (presenting VA<6/60) were solely attributable to glaucoma. The mean optic disc diameter was 1.93 mm (SD 0.19) for left and right eyes, while the mean CDR for right eyes was 0.44 (SD 0.15) and for left eyes 0.43 (SD 0.16). Conclusions: This population-based study examined the prevalence of glaucoma within the Indigenous Australian population, and although an infrequent cause of vision loss, definable rates of disease were seen. The results may suggest a potential introduction of Caucasian glaucoma-associated genes into this community, differently used diagnostic criteria or sampling bias compared with previous surveys.