Reliability of Intra-Retinal Layer Thickness Estimates.
OBJECTIVE
Measurement of intra-retinal layer thickness using optical coherence tomography (OCT) has become increasingly prominent in multiple sclerosis (MS) research. Nevertheless, the approaches used for determining the mean layer thicknesses vary greatly. Insufficient data exist on the reliability of different thickness estimates, which is crucial for their application in clinical studies. This study addresses this lack by evaluating the repeatability of different thickness estimates.


METHODS
Studies that used intra-retinal layer segmentation of macular OCT scans in patients with MS were retrieved from PubMed. To investigate the repeatability of previously applied layer estimation approaches, we generated datasets of repeating measurements of 15 healthy subjects and 13 multiple sclerosis patients using two OCT devices (Cirrus HD-OCT and Spectralis SD-OCT). We calculated each thickness estimate in each repeated session and analyzed repeatability using intra-class correlation coefficients and coefficients of repeatability.


RESULTS
We identified 27 articles, eleven of them used the Spectralis SD-OCT, nine Cirrus HD-OCT, two studies used both devices and two studies applied RTVue-100. Topcon OCT-1000, Stratus OCT and a research device were used in one study each. In the studies that used the Spectralis, ten different thickness estimates were identified, while thickness estimates of the Cirrus OCT were based on two different scan settings. In the simulation dataset, thickness estimates averaging larger areas showed an excellent repeatability for all retinal layers except the outer plexiform layer (OPL).


CONCLUSIONS
Given the good reliability, the thickness estimate of the 6mm-diameter area around the fovea should be favored when OCT is used in clinical research. Assessment of the OPL was weak in general and needs further investigation before OPL thickness can be used as a reliable parameter.
NeuroCure Clinical Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany.
Timm
T
Oberwahrenbrock
Optics and Laser Technology Laboratory, Beuth University of Applied Sciences, Berlin, Germany.
Maria
M
Weinhold
NeuroCure Clinical Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany.
Janine
J
Mikolajczak
NeuroCure Clinical Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany.
Hanna
H
Zimmermann
NeuroCure Clinical Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany; Department of Neurology, Charité-Universitätsmedizin, Berlin, Germany.
Friedemann
F
Paul
Optics and Laser Technology Laboratory, Beuth University of Applied Sciences, Berlin, Germany.
Ingeborg
I
Beckers
NeuroCure Clinical Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany.
Alexander U
AU
Brandt
D005584:Fovea Centralis / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D009103:Multiple Sclerosis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D009412:Nerve Fibers / Q000000981:diagnostic imaging / Q000473:pathology; D011859:Radiography; D012160:Retina / Q000000981:diagnostic imaging / Q000503:physiopathology*; D041623:Tomography, Optical Coherence