Choroidal Thickness in Indigenous Australian Children

PURPOSE: This study aimed to examine the choroidal thickness profiles in visually normal Australian Indigenous children, given the important role of the choroid in refractive error and a range of ocular diseases. METHODS: Choroidal thickness was assessed across the central 5 mm macular region using enhanced depth imaging spectral domain optical coherence tomography, in 250 children enrolled in an elementary school and a secondary school in rural Queensland, Australia. One hundred (40%) of these children identified as Indigenous Australians. RESULTS: The subfoveal choroid was significantly thicker in Indigenous children (mean 369 ± 75 µm), compared to non-Indigenous children (355 ± 73 µm; P = 0.03). Subfoveal choroidal thickness was also significantly associated with age (β = +7.6, r(2) = 0.105, P = 0.003), and axial length (β = −19.9, r(2) = 0.030, P < 0.001). A significantly thicker choroid in Indigenous children was also found in analyses across the central 5 mm macular region (P = 0.008). A significant interaction between Indigenous status and meridian was observed (P = 0.007) with the largest differences between Indigenous and non-Indigenous children being in the nasal and inferonasal meridians. CONCLUSIONS: This study establishes the normative characteristics of macular choroidal thickness in Indigenous Australian children and demonstrates a significantly thicker choroid compared to non-Indigenous children from the same geographic region. These results may have implications for our understanding of factors predisposing or protecting Australian Indigenous people from a range of conditions associated with choroidal thickness. TRANSLATIONAL RELEVANCE: The significantly thicker choroid in Australian Indigenous children should be considered in clinical diagnoses and management of conditions associated with choroidal changes.