Abstract
Purpose: :
To evaluate the discrepancy of the Retinal and RNFL thickness measurements between a Spectral-Domain OCT (3D OCT-1000, Topcon) and a Time-Domain OCT (StratusTM OCT, Carl Zeiss Meditec).
Methods: :
A total of 25 healthy subjects were scanned with Topcon SD-OCT and StratusTM TD-OCT. One eye per subject was chosen randomly, and was scanned three times successively with a line scan (6mm horizontal line, centered on the fovea) and a circle scan (3.45mm diameter, centered on the optic disc) protocols. Minimum image quality was required for Topcon (Quality Factor ≥ 45) and StratusTM scans (Signal Strength ≥ 5) to ensure software performance of accurate layer segmentation. For the line scans, the thickness between boundaries of inner limiting membrane (ILM) and IS/OS (ILM-IS/OS), ILM to the anterior boundary of RPE (ILM-RPE), and ILM to the posterior boundary of RPE/Bruch’s membrane (ILM-BM) were measured in Topcon scans, and compared with the retinal thickness measurement in StratusTM . Similarly, for the circle scans, the RNFL thickness measurement were performed and compared between Topcon and StratusTM scans. The average thickness values were calculated and paired to assess the measurement discrepancy and linear regression analysis were applied.
Results: :
The average thicknesses (mean ± SD) of ILM-IS/OS, ILM-RPE, and ILM-BM in Topcon scans were 237.2±10.7µm, 256.0±11.0µm, and 298.5±11.5µm respectively, comparing to 238.7±14.1 µm for the retinal thickness measurements in StratusTM. Slope, intercept, and the square of the correlation coefficient (R2) from the linear regression between ILM-IS/OS versus StratusTM retinal thickness measurement were 0.9845, 4.0769, and 0.9480; 0.9949, 15.959, 0.9164 for ILM-RPE; and 1.0425, 71.666, 0.9029 for ILM-BM. For RNFL thickness, the average thickness was 105.8±11.2µm in Topcon versus 104.9±10.2µm in Stratus, and the linear regression parameters were 0.9269, 6.1771, and 0.9486.
Conclusions: :
In this set of data sample from healthy subjects, the retinal and RNFL thickness results are comparable between TOPCON SD-OCT and StratusTM TD-OCT.
Keywords: imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina