AIM: To investigate blood flow density within 300μm(FD-300)around the foveal avascular zone(FAZ)in optical coherence tomography angiography(OCTA)of patients with macular edema(ME)complicated with non-ischemic branch retinal vein occlusion(BRVO), and to explore and evaluate the predictive effect of this parameter on the number of intraocular drug injections.

METHODS: A retrospective case study. A total of 50 patients(50 eyes)who were diagnosed as non-ischemic BRVO combined with ME and received intravitreal conbercept(IVC)in the Affiliated Eye Hospital of Nanjing Medical University from January 2021 to March 2022 were selected, and they were treated with 3+PRN regimen. The 25 cases(25 eyes)treated with intraocular injection ≤5 times were classified as group B, and 25 cases(25 eyes)treated with intraocular injection >5 times were classified as group C, and 25 fellow eyes were randomly selected as control group A. OCTA was used to scan the macular area in 3mm×3mm to collect images of retinal blood flow, the central macular thickness(CMT)and FD-300. The CMT, best-corrected visual acuity(BCVA), and FD-300 were compared between the two groups at baseline, 1, 3, 6 and 12mo after the third injection.

RESULTS: The BCVA(LogMAR)of the affected eye in both groups B and C at 1, 3, 6 and 12mo after the third injection was significantly lower than baseline(all P<0.05); the CMT and FD-300 were significantly lower than baseline(all P<0.05). Pearson correlation analysis showed that the change of BCVA(LogMAR)was positively correlated with the baseline FD-300 and CMT(group B: r=0.77, 0.70, all P<0.01; group C: r=0.89, 0.78, all P<0.01). The number of intraocular injections was negatively correlated with the baseline FD-300(group B: r=-0.63, P<0.01; group C: r=-0.71, P<0.01). Logistic regression analysis showed that the FD-300 at baseline is a factor that affects the number of intraocular drug injection.

CONCLUSION: IVC can effectively alleviate macular edema of the affected eye,improve visual acuity and reduce FD-300. The eyes with worse BCVA and lower FD-300 at baseline may require more injections of anti-VEGF. Observation of FD-300 with OCTA can better predict eventual vision recovery of non-ischemic BRVO with ME before treatment.