Logo image
Total retinal thickness: a neglected factor in the evaluation of inner retinal thickness
Journal article   Open access   Peer reviewed

Total retinal thickness: a neglected factor in the evaluation of inner retinal thickness

Mark Banghart, Kyungmoo Lee, Mozhdeh Bahrainian, Kristen Staggers, Christopher Amos, Yao Liu, Amitha Domalpally, Benjamin J Frankfort, Elliott H Sohn, Michael Abramoff, …
BMJ open ophthalmology, Vol.7(1), e001061
09/30/2022
DOI: 10.1136/bmjophth-2022-001061
PMCID: PMC9528673
PMID: 36329022
url
https://doi.org/10.1136/bmjophth-2022-001061View
Published (Version of record) Open Access

Abstract

AimTo determine whether macular retinal nerve fibre layer (mRNFL) and ganglion cell-inner plexiform layer (GC-IPL) thicknesses vary by ethnicity after accounting for total retinal thickness.MethodsWe included healthy participants from the UK Biobank cohort who underwent macula-centred spectral domain-optical coherence tomography scans. mRNFL and GC-IPL thicknesses were determined for groups from different self-reported ethnic backgrounds. Multivariable regression models adjusting for covariables including age, gender, ethnicity and refractive error were built, with and without adjusting for total retinal thickness.Results20237 participants were analysed. Prior to accounting for total retinal thickness, mRNFL thickness was on average 0.9 μm (−1.2, –0.6; p<0.001) lower among Asians and 1.5 μm (−2.3, –0.6; p<0.001) lower among black participants compared with white participants. Prior to accounting for total retinal thickness, the average GC-IPL thickness was 1.9 μm (−2.5, –1.4; p<0.001) lower among Asians compared with white participants, and 2.4 μm (−3.9, –1.0; p=0.001) lower among black participants compared with white participants. After accounting for total retinal thickness, the layer thicknesses were not significantly different among ethnic groups. When considered as a proportion of total retinal thickness, mRNFL thickness was ~0.1 and GC-IPL thickness was ~0.2 across age, gender and ethnic groups.ConclusionsThe previously reported ethnic differences in layer thickness among groups are likely driven by differences in total retinal thickness. Our results suggest using layer thickness ratio (retinal layer thicknesses/total retinal thickness) rather than absolute thickness values when comparing retinal layer thicknesses across groups.
Imaging Macula Original research Retina

Details

Metrics

Logo image