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Zach Nadler, Bo Wang, Gadi Wollstein, Daniel Hammer, R. Ferguson, Hiroshi Ishikawa, Richard Bilonick, Jessica Nevins, Larry Kagemann, Joel Schuman; Repeatability of Three-Dimensional (3D) Microstructural Parameters of the Lamina Cribrosa (LC) in Adaptive Optics Spectral-Domain Optical Coherence Tomography (AO-SDOCT). Invest. Ophthalmol. Vis. Sci. 2013;54(15):2638.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate imprecision of 3D LC microstructural parameters derived from automated analysis of scans taken using AO-SDOCT.
A multimodal AO retinal imaging system (Physical Sciences Inc., Andover MA), which includes SDOCT and scanning laser ophthalmoscopy (SLO) imaging channels, was used in this study. The OCT channel light source is centered at 1050 nm with isotropic axial and transverse resolution of ~4μm and a scanning rate of 28kHz. AO correction is applied to both OCT and SLO channels at ~20fps. Each eye was scanned twice, using a 6°x6° window centered on the LC. The OCT channel has 1024 A-lines per B-scan and 200 B-scans per volume. The en face SLO frames were used in precise registration of OCT B-scans for a 3D reconstruction. LC pores were segmented using an automated adaptive local thresholding technique of our own design. All processing was performed using Fiji (ImageJ 1.47c, NIH, http://imagej.nih.gov/ij). Tested parameters include: pore number, average pore cross-sectional area, mean laminar beam thickness, and ratio of average pore diameter to average beam thickness. Repeatability was assessed by computing measurement imprecision.
Eight healthy and 12 glaucomatous eyes were included in this study. The results for microstructural parameter averages and imprecision are summarized in the Table. For all parameters the imprecision is small in comparison to the mean values, which indicates high repeatability.
Global parameters quantifying microstructure of the LC, as recorded with multimodal AO-SDOCT, are highly repeatable, as indicated by the low imprecision, and may be used to further probe 3D structural differences between healthy and glaucomatous eyes.
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