PCD displayed significant correlations with morphological and functional indices and exhibited diagnostic capabilities comparable to currently employed clinical variables. Our preliminary results suggest that PCD analysis may prove to be a useful tool in monitoring POAG across stage and identifying early POAG.

ObjectivesTo assess the effect of image registration and averaging on the visualization and quantification of the radial peripapillary capillary (RPC) network on optical coherence tomography angiography (OCTA).MethodsTwenty-two healthy controls were imaged with a commercial OCTA system (AngioVue, Optovue, Inc.). Ten 10x10° scans of the optic disc were obtained, and the most superficial layer (50-μm slab extending from the inner limiting membrane) was extracted for analysis. Rigid registration was achieved using ImageJ, and averaging of each 2 to 10 frames was performed in five ~2x2° regions of interest (ROI) located 1° from the optic disc margin. The ROI were automatically skeletonized. Signal-to-noise ratio (SNR), number of endpoints and mean capillary length from the skeleton, capillary density, and mean intercapillary distance (ICD) were measured for the reference and each averaged ROI. Repeated measures analysis of variance was used to assess statistical significance. Three patients with primary open angle glaucoma were also imaged to compare RPC density to controls.ResultsQualitatively, vessels appeared smoother and closer to histologic descriptions with increasing number of averaged frames. Quantitatively, number of endpoints decreased by 51%, and SNR, mean capillary length, capillary density, and ICD increased by 44%, 91%, 11%, and 4.5% from single frame to 10-frame averaged, respectively. The 10-frame averaged images from the glaucomatous eyes revealed decreased density correlating to visual field defects and retinal nerve fiber layer thinning.ConclusionsOCTA image registration and averaging is a viable and accessible method to enhance the visualization of RPCs, with significant improvements in image quality and RPC quantitative parameters. With this technique, we will be able to non-invasively and reliably study RPC involvement in diseases such as glaucoma.

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PurposeTo determine and compare the diagnostic performance of spectral-domain optical coherence tomography (SD-OCT), stereoscopic disc photographs, and automated perimetry as assessed by a group of glaucoma specialists in differentiating individuals with early glaucoma from suspects.MethodsForty-six eyes (46 patients) with suspicious optic nerves had previously undergone SD-OCT scans, 24-2 visual fields (VFs), and optic disc photographs. The average VF mean deviation was −1.97 ± 2.09 (SD) dB. Four glaucoma specialists examined the 138 individual diagnostic tests and classified the patient as likely glaucomatous or nonglaucomatous based on the results of a single test. The diagnostic performances of each of the three tests were compared to a previously determined reference standard, based on the consensus of a separate panel of four glaucoma specialists who examined all three tests together.ResultsAmong the four specialists, the interobserver agreement across the three diagnostic tests was poor for VF and photos, with kappa (κ) values of 0.13 and 0.16, respectively, and moderate for OCT, with κ value of 0.40. Using panel consensus as reference standard, OCT had the highest discriminative ability, with an area under the curve (AUC) of 0.99 (95% 0.96–1.0) compared to photograph AUC 0.85 (95% 0.73–0.96) and VF AUC 0.86 (95% 0.76–0.96), suggestive of closer performance to that of a group of glaucoma specialists.ConclusionsCompared to VF and disc photography, SD-OCT, when used alone, had better internal agreement as well as better agreement with the consensus of clinicians using all available data. Future studies should evaluate best practices for SD-OCT interpretation.