Abstract
Purpose :
Australian Indigenous adolescents are 8x more likely to develop type 2 diabetes than non-Indigenous adolescents, while Indigenous adults are 3x more likely to develop vision loss from diabetic retinopathy (DR). Given this high risk profile and evidence that early macular neurodegenerative changes, characterised by inner retinal layer thinning, are evident before the clinical onset of DR, we explored the normal macula thickness profile of Australian Indigenous children without systemic disease. This data is important for accurate and early detection of DR and advanced understanding of structural risk factors.
Methods :
Participants included 126 children aged 5 to 12 years (mean age 8.9±2.1 years); 46% identified as Aboriginal and/or Torres Strait Islander (Indigenous Australian). Six high resolution, foveal centred optical coherence tomography scans (Heidelberg Spectralis) were captured from the right eye. Each scan was analysed using automated segmentation to determine the thickness of 6 defined retinal layers, as well as total thickness across the macula region; 1mm foveal zone, 3mm parafoveal zone, and 6mm perifoveal zone.
Results :
Across the macula region, the retina was significantly thinner in Indigenous children within the foveal zone (255.4±17.6µm vs 267.7±16.8µm; p<0.01), but not in the parafoveal or perifoveal zones. Differences in total retinal thickness in the foveal zone were greatest in the inferior and infero-nasal locations. All analyses were adjusted for age and refractive error.
Differences were observed in both the inner and outer retinal layers. The outer nuclear plus outer plexiform layers were thinner in Indigenous children in the foveal (97.0±7.3µm vs 101.4±7.8µm; p=0.01) and perifoveal zones (76.9±5.3µm vs 79.1±7.5 µm; p=0.02), and the inner plexiform plus ganglion cell layers were thinner in the parafoveal zone (91.7±5.6µm vs 95.0±5.4µm; p=0.01). No difference was observed in nerve fibre layer thickness.
Conclusions :
Retinal thinning was evident in healthy Indigenous children compared to non-Indigenous children in both the inner and outer retinal layers which is highly relevant when assessing early neurodegenerative retinal changes in diabetes. Future studies should investigate whether baseline retinal thinning is associated with the higher prevalence of vision-threatening DR among Indigenous Australians.
This is a 2020 ARVO Annual Meeting abstract.