The prevalence of diabetes among Aboriginal and Torres Strait Islander (hereafter ‘Aboriginal’) Australians is three times greater than non-Aboriginal Australians, contributing to a greater risk of blindness from treatable and preventable ocular conditions, most prominently cataract and diabetic retinopathy. In rural and remote Aboriginal communities, blindness prevalence is higher, and ocular treatment coverage and uptake are lower. In collaboration with Aboriginal Community Based Researchers (CBRs), this study explored complex contingent factors that shape access to eye health services among rural and remote Aboriginal Australians living with diabetes. Interviews (n = 126) and focus groups (n = 12) were conducted with patients, primary care clinicians, and CBRs, in four rural communities in the Northern Territory and New South Wales. Factors internal and external to health systems were examined, drawing on Bourdieu's concepts of habitus, and doxa to understand agency and decision-making among patients and clinicians. The study used the ontology of critical realism, categorising contingent factors as underlying structures (generative mechanisms), and applying a decolonising approach that centred causal relationships and tensions between dominant (Western biomedical neoliberalism) and non-dominant (Aboriginal) value systems. Three forms of marginalisation; linguistic, economic, and cultural, were identified as the generative mechanisms that inhibit equitable eye health outcomes. Marginality is linked to structural factors that position Aboriginal culture as a barrier, and is reinforced through biomedical health systems, and the agents who operate in and influence them. In order to address eye health inequity, a shift in how Aboriginal cultural sovereignty is understood within health systems is needed, to position it as a strength that can facilitate eye care accessibility, and to support enhanced cultural responsivity among clinicians and service providers.