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Ahmed M Hagag, Alex David Pechauer, Liang Liu, JIE WANG, Zhang Miao, Yali Jia, David Huang; Optical coherence tomography angiography changes in the three parafoveal retinal plexuses in response to hyperoxia. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4751.
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© ARVO (1962-2015); The Authors (2016-present)
Use projection-resolved optical coherence tomography angiography (PR-OCTA) to investigate the autoregulatory response in the three parafoveal retinal plexuses under hyperoxia.
Nine eyes from 9 healthy participants were scanned using a commercial spectral-domain OCT system. Two repeated macular scans (3 x 3 mm2) were acquired at baseline and during oxygen breathing. Split-spectrum amplitude-decorrelation algorithm (SSADA) was used to detect blood flow. The PR algorithm was used to suppress projection artifacts and resolve blood flow in three distinct parafoveal plexuses. Flow index and vessel density were calculated from the en face angiograms of each of the three plexuses, as well as from the all-plexus inner retinal slab. The Wilcoxon signed-rank test was used to compare between baseline and hyperoxic parameters. Coefficient of variation (CV) and pooled standard deviation (SD) were used to assess the within-session repeatability of baseline measurements and between-day reproducibility of the hyperoxic response, respectively.
Hyperoxia induced significant reduction in the flow index (-11%) and vessel density (-7.8%) of only the deep capillary plexus (DCP, p < 0.001) and in the flow index of the all-plexus slab (p = 0.015) (Table 1). The flow index also decreased in the intermediate capillary plexus (ICP) and the superficial vascular complex (SVC), but these changes were small (Figure 1) and not statistically significant (Table 1). The PR-OCTA showed good within-session baseline repeatability (CV, 0.8%-5.2%) in all parameters (Table1). Relatively large between-day response reproducibility was observed (pooled SD, 1.7%-9.4%) (Table 1).
Projection-resolved OCTA was able to show that the retinal autoregulatory response to hyperoxia affects only the DCP, but not the ICP or SVC.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
En face angiograms of superficial, intermediate and deep parafoveal vascular plexuses of the same participant during baseline scan session (A-C), and after hyperoxia (D-F). Note the difference in flow signal (color scale) and vessel density between baseline and hyperoxia. The decrease is visually apparent in the deep capillary plexus (DCP), but not in the superficial vascular complex (SVC) or intermediate capillary plexus (ICP)
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