NONPERFUSION AREA QUANTIFICATION IN BRANCH RETINAL VEIN OCCLUSION: A WIDEFIELD OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY STUDY.

PURPOSE To precisely quantify retinal nonperfusion areas (NPAs) in branch retinal vein occlusion (BRVO) using widefield optical coherence tomography angiography (OCTA), and examine their association with neovascular complications. METHODS We enrolled 26 patients with treatment-naive BRVO and prospectively examined them for 12 months. After three monthly ranibizumab injections to treat macular edema, each patient underwent ultra-wide field (UWF) fluorescein angiography (FA) and OCTA. UWF FA was additionally performed at Month 12. For UWF FA, the retinal NPA was measured using the equipment's built-in software. For OCTA, we used panoramic image montaged from 5 single 12×12 mm images and quantified the retinal NPA using a Gullstrand eye with a grid scale at each patient. Measurements were expressed in terms of actual values and disc area (DA) units. RESULTS The retinal NPAs as measured using single OCTA and panoramic OCTA were significantly associated with that measured using UWF FA (P < 0.001 for both). Retinal neovascularization (NV) lesions were observed in four (15.4%) of 26 eyes. For patients with accompanying NV, the retinal NPA measured using UWF FA, single OCTA, and panoramic OCTA were 187.9 ± 39.5 mm (109.9 ± 21.4 DA), 34.3 ± 13.7 mm (19.9 ± 7.7 DA), and 106.6 ± 24.5 mm (62.4 ± 13.6 DA), respectively, which were larger than for those without NV (P < 0.001, 0.014, and <0.001, respectively). CONCLUSIONS Using widefield OCTA, we could quantify the retinal NPA of eyes with BRVO. These could serve as valid references to assess the risk of neovascular complications.