Abstract
Purpose: :
To compare Fourier-Domain and Time-Domain Optical Coherence Tomography (OCT) measurements of peripapillary retinal nerve fiber layer (RNFL) thickness.
Methods: :
This study involved 41 healthy volunteers. One eye was randomly chosen for study purposes. All subjects underwent a complete ophthalmological evaluation and optic nerve head imaging with Fourier-Domain OCT (OPKO Spectral OCT/SLO, software version 1.76, Ophthalmic Technologies Inc, Toronto, Canada) using the "RNFL" protocol and Time-Domain OCT (Stratus OCT, software version 4.0, Carl Zeiss Meditec Inc, Dublin, CA, USA) using the "Fast RNFL Thickness 3.4" protocol. Mean values were compared by paired t-test. The agreement between Spectral OCT/SLO and Stratus OCT was evaluated by Bland-Altman plots.
Results: :
Mean age was 38 ± 8.3 years. Average RNFL thickness with Spectral OCT/SLO (109.17 µm) was significantly higher than Stratus OCT (101.17 µm). Spectral OCT estimates were also higher than Stratus OCT in the superior (129.61 µm vs. 127.12 µm respectively, p=0.14), temporal (75.78 µm vs. 69.56 µm, p<0.001), inferior (134.51 µm vs. 127.93 µm, p<0.001), nasal (96.63 µm vs. 79.76 µm, p<0.001) sectors. The difference between Spectral OCT/SLO and Stratus OCT estimates of the average RNFL thickness was within ± 12 µm in 95% of the patients.
Conclusions: :
Spectral OCT/SLO RNFL measurements were moderately higher than Stratus OCT in the inferior, temporal and superior sectors. A more significant overestimation was found in the nasal sector.
Keywords: nerve fiber layer • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • optic disc