Comparative Quantitative Analysis of Retinal Superficial Capillary Plexus in Patients with Retinal Vein Occlusion and Unaffected Fellow Eyes

Purpose: To evaluate optical coherence tomography angiography (OCT-A) data obtained from the superficial retinal capillary plexus of patients with retinal vein occlusion and comparative analysis with data registered from unaffected fellow eyes. Methods: The examined patients were classified into 2 groups: group 1—eyes with established retinal vein occlusion (n = 29) and group 2—unaffected fellow eyes of patients with retinal vein occlusion (n = 24). The scanning protocol “Angiography 3 × 3 mm” of Zeiss Cirrus HD-OCT 6000, AngioPlex Metrix was used to evaluate the retinal superficial capillary plexus. The analyzed parameters were vascular density and perfusion density, as well as the area, perimeter, and circularity of the foveolar avascular zone (FAZ). Results: The comparative analysis of FAZ parameters at the superficial capillary plexus (SCP) between group 1 (eyes with retinal vein occlusion) and group 2 (unaffected fellow eyes) showed significant results for the three parameters, respectively area (p = 0.003), perimeter (p ≤ 0.001), and circularity (p = 0.011) of FAZ. The comparative analysis of the vascular network at SCP in patients with diagnosed retinal vein occlusion and unaffected fellow eyes showed significant results for vascular density (VD) in the central (p = 0.038) and inner (p ≤ 0.001) zones as well as total VD (p ≤ 0.001) were statistically significant. Moreover, the results obtained in the study of vascular perfusion (VP) indicated significant results in the inner zone (p ≤ 0.001) and total VP (p = 0.001). Vascular perfusion in the central zone (p = 0.116) was the only parameter not to meet significant results. Conclusion: The current study observed a significant enlargement of the FAZ and loss of its circularity, along with a reduction in vascular network parameters at the superficial retinal capillary plexus level.

Repeatability and Reproducibility of Quantitative Assessment of the Retinal Microvasculature Using Optical Coherence Tomography Angiography Based on Optical Microangiography

Objective The aim of this study was to determine the repeatability and reproducibility of optical coherence tomography angiography（OCTA） based on optical microangiography（OMAG） measurements of macular vessels in normal eyes. Methods In this prospective cohort study, 40 eyes of 40 healthy volunteers underwent repeated OCTA（Cirrus HD-OCT 5000 angiography system, Carl Zeiss Meditec, Inc.） scans on two separate visit days. On each visit day, the eyes were scanned three times. The following parameters were used to quantitatively describe the OCTA images of the superficial vascular network： vessel area density（VAD）, vessel skeleton density（VSD）, vessel diameter index（VDI）, vessel perimeter index（VPI）, vessel complexity index（VCI）, flux, and foveal avascular zone（FAZ）. Coefficient of variation（CV） and intraclass correlation coefficient（ICC） were calculated for evaluating intravisit and intervisit repeatability, as well as interobserver reproducibility. Results The measurements showed high repeatability [CVs ≤ 4.2%（intravisit） and ≤ 4.6%（intervisit）] and interobserver reproducibility（ICCs ≥ 0.923） for all parameters. Conclusion This study demonstrated good repeatability and reproducibility of OCTA based on OMAG for the measurement of superficial vessel parameters in normal eyes.