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Beth Edmunds, Liang Liu, Yali Jia, Miao Zhang, Simon S. Gao, Hana L Takusagawa, John C Morrison, David Huang; Projection-Resolved Optical Coherence Tomography Angiography of the Peripapillary Retina in Glaucoma. Invest. Ophthalmol. Vis. Sci. 2017;58(8):721.
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© ARVO (1962-2015); The Authors (2016-present)
To detect plexus-specific peripapillary retinal perfusion defects in glaucoma using projection-resolved optical coherence tomography angiography (PR-OCTA).
This observational study enrolled primary open angle glaucoma and age-matched normal control subjects. One eye of each subject was scanned using the AngioVue 4.5-mm OCTA scan centered on the disc. The scans were exported and analyzed using a custom PR-OCTA algorithm that removed flow projection artifacts. Four en face OCTA slabs were analyzed (Fig.1): the radial peripapillary capillary plexus (RPCP); the superficial vascular complex (SVC = RPCP + superficial capillary plexus); the deep vascular complex (DVC = intermediate + deep capillary plexuses); (4) all plexuses combined. The vessel density (VD), defined as the percentage area occupied by flow pixels, was calculated from a 4×4 mm square centered on the disc using a reflectance-compensated algorithm.
40 glaucoma and 38 normal subjects were analyzed. In glaucoma, focal capillary dropout could be visualized more clearly in the RPCP slab than in the SVC and all-plexus angiograms (Fig.2), while the DVC appeared unaffected. The RPCP, SVC and all-plexus VD in the glaucoma group (mean±SD, 53%±12% , 66%±10% and 82%±9%) was lower than the normal group (76%±6%, 83%±4% and 92%±3%, all P <0.001, t-test). There was no significant difference in DVC VD between the two groups (P=0.171). Among the overall parameters, the RPCP VD had the best diagnostic accuracy (0.941) as measured by the area under the receiver operating characteristic curve (AROC). The accuracy was even better when the worse hemisphere (inferior or superior) was used, achieving an AROC of 0.953 and a sensitivity of 90% at a specificity of 95%. The hemispheric RPCP VD was correlated with corresponding retinal nerve fiber layer thickness and visual field sensitivity (Pearson R=0.889 and 0.643, P<0.001).
Glaucoma preferentially affects RPCP perfusion in the peripapillary retina more than the deeper plexuses. Reflectance-compensated RPCP VD measurement by PR-OCTA detected glaucoma with high accuracy and could be useful in the clinical evaluation of glaucoma.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
Figure 1. Relationship between the retinal vascular plexuses and anatomic layers.
Figure 2. Focal capillary dropout (arrow) could be visualized in RPCP, SVC and all-plexus retina angiograms, but not in DVC.
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