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<h5 class="section-title" id="d1211303e187">Purpose</h5>
<p id="P2">To detect macular perfusion defects in glaucoma using projection-resolved
optical
coherence tomography (OCT) angiography.
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<h5 class="section-title" id="d1211303e192">Design</h5>
<p id="P3">Prospective observation study.</p>
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<h5 class="section-title" id="d1211303e197">Participants</h5>
<p id="P4">30 perimetric glaucoma and 30 age-matched normal participants were included.</p>
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<h5 class="section-title" id="d1211303e202">Methods</h5>
<p id="P5">One eye of each participant was imaged using 6mm×6mm macular OCT angiography
(OCTA)
scan pattern by 70-kHz 840-nm spectral-domain OCT. Flow signal was calculated by the
split-spectrum amplitude-decorrelation angiography algorithm (SSADA). A projection-resolved
OCTA (PR-OCTA) algorithm was used to remove flow projection artifacts. Four
<i>en face</i> OCTA slabs were analyzed: the superficial vascular complex (SVC), intermediate
capillary
plexus (ICP), deep capillary plexus (DCP) and all-plexus retina (SVC+ICP+DCP). The
vessel density (VD), defined as the percentage area occupied by flow pixels, was calculated
from
<i>en face</i> OCTA. A novel algorithm was used to adjust the vessel density to compensate
for local
variations in OCT signal strength.
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<h5 class="section-title" id="d1211303e213">Main Outcome Measures</h5>
<p id="P6">Macular retinal VD, ganglion cell complex (GCC) thickness, and visual field
(VF) sensitivity.</p>
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<h5 class="section-title" id="d1211303e218">Results</h5>
<p id="P7">Focal capillary dropout could be visualized in the SVC, but not the ICP
and DVP, in
glaucomatous eyes. In the glaucoma group, the SVC and all-plexus retinal VD (mean±SD:
47.2%±7.1% and 73.5%±6.6%) were lower than the normal group (60.5%±4.0% and 83.2%±4.2%,
both P <0.001, t test). The ICP and DCP VD were not significantly lower in the
glaucoma
group. Among the overall macular VD parameters, the SVC VD had the best diagnostic
accuracy 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 0.983 and a sensitivity of 96.7% at a specificity of
95%. Among the glaucoma participants, the hemispheric SVC VD values were highly correlated
with the corresponding GCC thickness and VF sensitivity (P<0.003). The reflectance
compensation step in VD calculation significantly improved repeatability, normal population
variation, and correlation with VF and GCC thickness.
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<h5 class="section-title" id="d1211303e223">Conclusions</h5>
<p id="P8">Based on PR-OCTA, glaucoma preferentially affects perfusion in the SVC
in the macula
more than the deeper plexuses. Reflectance-compensated SVC VD measurement by PR-OCTA
detected glaucoma with high accuracy and could be useful in the clinical evaluation
of glaucoma.
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