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Systematic ultrastructural comparison of swept-source and full-depth spectral domain optical coherence tomography imaging of diabetic macular oedema
  1. Christoph Mitsch1,
  2. Jan Lammer1,
  3. Sonja Karst1,
  4. Christoph Scholda1,
  5. Eleonore Pablik2,
  6. Ursula Margarethe Schmidt-Erfurth1
  1. 1 Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
  2. 2 Center for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Vienna, Austria
  1. Correspondence to Ursula Margarethe Schmidt-Erfurth, Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria;{at}


Background/Aims Optical coherence tomography (OCT) is commonly used to diagnose and assess diabetic macular oedema (DME). Swept-source OCT (SS-OCT) promises improved imaging depth and more independence from media opacities. Heidelberg Spectralis full-depth imaging (FDI) combines details at different depths to one representation. The aim of this study was to determine the comparability of the imaging methods concerning DME ultrastructure.

Methods Two graders assessed the presence of typical DME phenomena in eyes with centre-involving DME on Topcon Atlantis SS-OCT and Heidelberg Spectralis FDI spectral-domain OCT (SD-OCT) B-scans. Retinal layer segmentation was corrected and choroidal layers were manually segmented. Graders measured cyst and subretinal fluid (SRF) diameters and counted hyper-reflective foci (HRF). Findings were recorded and statistically analysed.

Results Statistically significant systematic biases (Spectralis-Atlantis) were found for the HRF count (outside the central mm, −6.39, p=0.0338), chorioretinal thickness (central mm: −35.45 µm, p=0.00034), choroidal thickness (central mm: −60.97 µm, p=0.00004) and Sattler’s layer thickness (−42.69 µm, p=0.0001). Intergrader agreement was excellent or very good for posterior vitreous detachment, vitreomacular attachment (central mm) and SRF presence in both devices. Manually delineated Sattler’s layer thickness showed an intraclass correlation of 0.85 with FDI SD-OCT but 0.26 with SS-OCT (p=0.003).

Conclusion Prominent aspects such as cysts in the outer nuclear layer and SRF can be identified with comparable confidence, while a significant systematic bias underlies chorioretinal, choroidal and Sattler’s layer thickness and HRF count. Specialists should use the same device at every examination during longitudinal clinical consideration or cross-sectional evaluation of these ultrastructural biomarkers.

  • Imaging
  • Macula
  • Choroid
  • Retina

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  • Contributors CM, UMS-E: planning, conduct and reporting. JL, SK, EP: conduct and reporting. CS: planning and conduct.

  • 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 Written informed consent was obtained from all participants in this study.

  • Ethics approval The study was approved by the Ethics Committee of the Medical University of Vienna, Austria.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement No additional data are available.

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