Purpose:
To evaluate the correlation between retinal nerve fiber layer (RNFL) thickness measured by Spectral Domain Optical Coherence Tomography (SD-OCT), Time-Domain OCT (TD-OCT), Confocal Scanning Laser Ophthalmoscopy (CSLO) and Scanning Laser Polarimetry (GDx-VCC) in healthy subjects and glaucomatous patients.
Methods:
Forty-four eyes of 23 healthy individuals and 31 eyes of 17 glaucomatous patients were included in this cross-sectional study. All participants underwent RNFL measurements using SD-OCT (Spectralis; software version 4.0, Heidelberg Engineering, Dossenheim, Germain), TD-OCT (Stratus; software version 5.0, Carl Zeiss Meditec, California, USA), GDx-VCC (Scanning Laser Polarimeter with variable cornea compensator, Laser Diagnostic Technologies, Inc., San Diego, CA, USA), HRT (Heildelberg Retina Tomograph, HRT-III, software version 3.1.2, Heildelberg Engineering GmbH, Deutschland.) on the same day. The correlation between RNFL thickness measurements obtained by SD-OCT (global thickness), TD-OCT (average thickness), GDx VCC (TSNIT average) and HRT (mean RNFL thickness) was calculated using the Spearman's rank correlation coefficient (r)
Results:
Mean (SD) RNFL measurements of the SD-OCT (global thickness), TD-OCT (average thickness), GDx VCC (TSNIT average) and HRT (mean RNFL thickness) were 93.0 (17.6) µm, 87.0 (18.0) µm, 54.3 (10.3) µm and 231.5 (65.3) µm, respectively. Correlations between RNFL thickness measurements were very strong for SD-OCT and TD-OCT (r=0.91; p<0.001); strong for SD-OCT and GDx (r=0.77; p<0.001), and moderate for TD-OCT and GDx (r=0.66; p<0.001) (table). The correlations between HRT RNFL thickness and the other devices were weak.
Conclusions:
RNFL thickness measurements with SD-OCT, TD-OCT, GDx VCC and HRT varied from weak to very strong. The strongest correlation was shown between SD-OCT and TD-OCT measurements.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: clinical • nerve fiber layer