Retinal nerve fibre layer thickness measurement reproducibility improved with spectral domain optical coherence tomography.
OBJECTIVE
To investigate retinal nerve fibre layer (RNFL) thickness measurement reproducibility using conventional time-domain optical coherence tomography (TD-OCT) and spectral-domain OCT (SD-OCT), and to evaluate two methods defining the optic nerve head (ONH) centring: Centred Each Time (CET) vs Centred Once (CO), in terms of RNFL thickness measurement variability on SD-OCT.


METHODS
Twenty-seven eyes (14 healthy subjects) had three circumpapillary scans with TD-OCT and three raster scans (three-dimensional or 3D image data) around ONH with SD-OCT. SD-OCT images were analysed in two ways: (1) CET: ONH centre was defined on each image separately and (2) CO: ONH centre was defined on one image and exported to other images after scan registration. After defining the ONH centre, a 3.4 mm diameter virtual circular OCT was resampled on SD-OCT images to mimic the conventional circumpapillary RNFL thickness measurements taken with TD-OCT.


RESULTS
CET and CO showed statistically significantly better reproducibility than TD-OCT except for 11:00 with CET. CET and CO methods showed similar reproducibility.


CONCLUSIONS
SD-OCT 3D cube data generally showed better RNFL measurement reproducibility than TD-OCT. The choice of ONH centring methods did not affect RNFL measurement reproducibility.
UPMC Eye Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, 203 Lothrop Street, Eye and Ear Institute, Suite 834, Pittsburgh, PA 15213, USA.
J S
JS
Kim
H
H
Ishikawa
K R
KR
Sung
J
J
Xu
G
G
Wollstein
R A
RA
Bilonick
M L
ML
Gabriele
L
L
Kagemann
J S
JS
Duker
J G
JG
Fujimoto
J S
JS
Schuman
D000328:Adult; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009898:Optic Disk / Q000473:pathology; D015203:Reproducibility of Results; D055351:Retinal Neurons / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000379:methods