Ocular biometry measures and their correlation with refractive error in Aboriginal and Torres Strait Islander children

Optical Coherence Tomography–Derived Measurements of the Optic Nerve Head Structure of Aboriginal and Torres Strait Islander Children

“…Importantly, Aboriginal and Torres Strait Islander adults have been shown to exhibit a thinner CCT (mean difference 30 µm) 33 and lower IOP (mean difference 4.3 mm Hg) 34 than non-Indigenous Australians. Similarly, previously published data from this cohort of children reported that Aboriginal and Torres Strait Islander children had a thinner CCT (mean difference 9 µm) and a lower IOP (mean difference 1.3 mm Hg) compared with non-Indigenous children 18 …”

“…All measurements were conducted between 9 am and 3 pm . Results from the analyses of refractive error, stereoacuity, color vision, ocular alignment, accommodation and vergence function, ocular biometry, and macular OCT measures in this population have been reported previously 18–21 …”

“…While it could be speculated that the lower IOP in this population negates the increased risk for glaucoma associated with the reduced CCT and larger ONHs, the magnitude of the difference in IOP previously reported is small and unlikely to account for the low rates of glaucoma reported. 18,34 Alternatively, as this study highlights, previous attempts to estimate the prevalence of glaucoma in this population may have been confounded by a range of factors that need to be considered when making a diagnosis of glaucoma in Aboriginal and Torres Strait Islander Australians. This includes a reduced CCT, which will result in an underestimation of IOP, large physiological cupping, and reduced BMO-MRW, which may mimic glaucomatous neuropathy making detection of true glaucoma more challenging.…”

“…Similarly, previously published data from this cohort of children reported that Aboriginal and Torres Strait Islander children had a thinner CCT (mean difference 9 µm) and a lower IOP (mean difference 1.3 mm Hg) compared with non-Indigenous children. 18 Given that numerous studies have shown an association between both thin CCT and larger ONHs with an increased risk of developing glaucoma in adulthood, [14][15][16][35][36][37][38][39] it is surprising that the limited available evidence suggests that Aboriginal and Torres Strait Islander adults exhibit low rates of glaucoma. 40,41 Current estimates on the prevalence of glaucoma in Aboriginal and Torres Strait Islander adults vary between 0.5% and 2.2% 6,40,41 compared with 1.8% to 3.0% among non-Indigenous Australians, 42,43 although it should be noted that the quality of evidence regarding the prevalence of glaucoma in Aboriginal and Torres Strait Islander adults is limited by variable testing protocols and lack of stringent and robust diagnostic criteria.…”

“…Results from the analyses of refractive error, stereoacuity, color vision, ocular alignment, accommodation and vergence function, ocular biometry, and macular OCT measures in this population have been reported previously. [18][19][20][21] The Heidelberg Spectralis SD-OCT uses a superluminescent diode with a central wavelength of 870 nm, capturing 40,000 A-scans per second, to generate images with a digital axial resolution of 3.9 µm and transverse resolution of ~5.8 µm. With the left eye occluded, 2 highresolution (1024 A-scans) ONH scans were performed, each consisting of a horizontal and a vertical 20-degree long scan, centered on the middle of the ONH to determine the vertical and horizontal dimensions of the ONH and neuroretinal rim and to measure the thickness of the peripapillary RNFL.…”