Comparison of widefield swept-source optical coherence tomography angiography with ultra-widefield fluorescein angiography for the evaluation of lesions in retinal vein occlusion

Background To compare widefield swept-source optical coherence tomography angiography (SS-OCTA) with ultra-widefield fundus fluorescein angiography (UWF-FA) for detecting retinal vein occlusion (RVO) lesions. Methods Thirty-four eyes of 32 patients with treatment-naïve RVO were enrolled at Peking University People’s Hospital from September 2021 to March 2022. Patients were imaged with a UWF-FA (200°) and a widefield SS-OCTA using 24 × 20 mm scan single capture. Quantitative assessments of RVO lesions such as foveal avascular zone (FAZ) area and perimeter, non-perfusion areas (NPA), number of microaneurysms (MAs), capillary changes and collateral vessels were performed. Results The measurement of FAZ area and perimeter were comparable between SS-OCTA and UWF-FA (0.373 (range, 0.277–0.48) mm 2 vs. 0.370 (range, 0.277–0.48) mm 2 , P = 0.818 and 2.480 (range, 2.011–2.998) vs. 2.330 (range, 2.027–2.807) mm, P = 0.536, respectively). Intraclass correlation coefficients (ICCs) of FAZ area and perimeter between SS-OCTA and UWF-FA was high (0.999, [0.997–0.999] and 0.996 [0.991–0.996], respectively), suggesting good agreement. The mean NPA area was larger on SS-OCTA than that on UWF-FA (89.977 ± 78.805 mm 2 vs. 87.944 ± 77.444 mm 2 , P = 0.037). The ICC of NPA area was also high (0.999, [0.999–1.000]). The median of total MA count was less on SS-OCTA than on UWF-FA (7 (range, 0–19) vs.12 (range, 0–23), P < 0.001). Agreement in detecting MAs between SS-OCTA and UWF-FA was found to be good (ICC = 0.920, [0.555–0.974]).The total capillary changes and collateral vessels count were less on UWF-FA than SS-OCTA (11 ± 9 vs 6 ± 7, P < 0.001 and 4 (range, 0–6) vs 0 (range, 0–0), P < 0.001, respectively). Agreement in detecting capillary changes and collateral vessels between OCTA and UWF-FA was found to be fair (ICC = 0.733, [0.081–0.905] and 0.564, [0.039–0.805], respectively). Conclusion Compared with UWF-FA, widefield SS-OCTA was found comparable or even superior in detecting FAZ, NPA, capillary changes and collateral vessels except MAs in RVO. Widefield SS-OCTA may offer a more efficient alternative to FA for diagnosis and monitoring RVO.