Background/aim Characterising genetic effect on macular retinal nerve fibre layer (RNFL) is needed to obtain better understanding of various retinopathies and optic neuropathies. The purpose of this study was to evaluate genetic influence on macular RNFL thickness.
Methods This is a cross-sectional, twin and family study. Three hundred and sixty-two Korean adults with healthy eyes were included in the study from 79 households with two or more family members. Macular RNFL thickness was measured with optical coherence tomography at nine macular subfields defined by the ETDRS. Intraclass correlation coefficients (ICCs) were estimated to assess intrafamilial resemblance of RNFL thickness by different types of family relationship. Heritability of RNFL thickness was evaluated using variance decomposition model.
Results RNFL thickness increased from central subfield to outer subfields. Temporal quadrant RNFL was thinner compared with other quadrants. Monozygotic twin pairs showed the highest ICCs of RNFL thickness, although the ICC level varied across different subfields. Heritability of RNFL thickness was the highest at central subfield (0.81). RNFL thicknesses of outer subfields were moderately to highly heritable: 0.53, 0.71, 0.47 and 0.66 for superior, inferior, temporal and nasal fields, respectively. RNFL thicknesses at inner subfields showed the lowest heritability: 0.21, 0.24, 0.27 and 0.27 for superior, inferior, temporal and nasal subfields, respectively.
Conclusion Macular RNFL thickness is significantly influenced by genetic factors. It varies largely by subfields with the highest heritability at the central subfield and a relatively lower heritability at inner subfields.
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SH and MK are joint first authors.
Contributors D-IH and Y-MS designed the study. HK, SH and MK analysed and interpreted the clinical data. SH and MK wrote the final paper. HK, D-IH and Y-MS reviewed the study design, reviewed the study results and reviewed the final paper. SH and MK equally contributed to the manuscript as cofirst author. D-IH and Y-MS equally contributed to the manuscript as the corresponding author. All authors read and approved the final manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval This study was approved by the Institutional Review Board (IRB) of Samsung Medical Center (IRB file number 2005-08-113). It adhered to tenets of the Declaration of Helsinki. Written informed consent was obtained from all participants.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon request.
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