Purpose
To test the hypothesis that the extent and reproducibility of anterior and posterior lamina cribrosa surface (ALCS and PLCS) and deep neural canal landmark delineation is enhanced within SDOCT 1050 nm vs 870 nm scans.
Methods
SDOCT 870 and 1050 Enhanced depth imaging radial B-scans (n=40, Spectralis, Heidelberg Engineering) were obtained 30 minutes after IOP was manometrically lowered to 10 mmHg, in both eyes of 12 non-human primates with various stages of unilateral early experimental glaucoma, during each of 2 sessions 2 weeks apart. To assess the extent of 870 vs 1050 delineation, the session 2 scans of each eye were delineated by 3 delineators. To assess inter-session reproducibility both session 1 and session 2 scans from 10 control eyes were delineated. To assess inter-delineator reproducibility, all 3 delineators delineated session 2 scans of 6 eyes. 25 parameters which describe the regional extent of ALCS and PLCS, ONH and RNFL (see table) were quantified for each scan. The regional extent of ALCS and PLCS between 870 and 1050 was compared using Poisson regression. Inter-session and inter-delineator reproducibility were assessed by the intra-class correlation coefficient [ICC].
Results
The number of sectors that could be successfully delineated was significantly larger for 1050 scans than 870 scans for ALCS (71 vs 65, p=0.009) in session 2. The extent of PLCS delineation was increased in 1050 scans but not significantly (70 vs 66, p=0.163). Inter-session ICC values (see table) ranged from 0.83-1.00 (mean±SD, 0.95±0.04) for 870 parameters and from 0.76-1.00 (0.95±0.04) for 1050 parameters. Inter-session ICC values <0.90 occurred in only 1 of 25 parameters for 870 and 2 for 1050. Inter-delineator ICC values ranged from 0.43-1.00 (0.86±0.20) for 870 parameters, and from 0.51-1.00 (0.88±0.17) for 1050 parameters. Inter-delineator ICC values <0.90 occurred in 8 of 25 parameters for 870 and 7 for 1050. The inter-delineator ICC for the parameter scleral canal area was improved from 0.43 (870) to 0.92 (1050).
Conclusions
These data suggest that SDOCT 1050 enhanced depth imaging modestly enhances deep ONH imaging in non-human primate eyes, and that inter-session and inter-delineator variability for both 870 and 1050 enhanced depth imaging ONH scans are excellent for most parameters.
Keywords: 629 optic nerve •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
577 lamina cribrosa