When monitoring patients with progressive diseases such as diabetic retinopathy, consistency is key. Keeping everything static (except the patient themselves) ensures doctors can gather the most information on the patient’s condition with the fewest mitigating factors. It’s for this reason that an Austrian research team recommends doctors use the same device at every examination during longitudinal clinical consideration or cross-sectional evaluation of diabetic retinopathy.
The investigators initially set out to determine whether spectral-domain OCT (SD-OCT) or swept-source OCT (SS-OCT) were superior for monitoring these patients. They found the two are essentially comparable with regards to this purpose. Specifically, they used the Atlantis SS-OCT (Topcon) and the Spectralis FDI SD-OCT (Heidelberg) in their research. They relied on two graders to assess the presence of typical diabetic macular edema in eyes with center-involved diabetic retinopathy. They measured cyst and subretinal fluid diameters and counted hyper-reflective foci. For the purposes of this study, the retinal layer segmentation images were corrected and choroidal layers were manually segmented.
The researchers found both devices were excellent or very good at helping identify posterior vitreous detachment, vitreomacular attachment and subretinal fluid presence. Manually delineated Sattler’s layer thickness showed an intraclass correlation of 0.85 with the SD-OCT, but 0.26 with SS-OCT. Statistically significant systematic biases were found within platforms, however, for the hyper-reflective foci count, chorioretinal thickness, choroidal thickness and Sattler’s layer thickness. Such findings prompted their recommendation to maintain device consistency as a means of eliminating avoidable variation.
|Mitsch C, Lammer J, Karst S. Systematic ultrastructural comparison of swept-source and full-depth spectral domain optical coherence tomography imaging of diabetic macular oedema. Br J Ophthalmol. August 31, 2019. [Epub ahead of print].|