Quantitative vascular density changes in choriocapillaris around CNV after anti-VEGF treatment: Dark Halo

BACKGROUND AND OBJECTIVE: The authors have observed and quantified choriocapillaris vascular density changes ("dark halo") around choroidal neovascularization (CNV) before and after anti-vascular endothelium growth factor (VEGF) injections by optical coherence tomography angiography (OCTA). PATIENTS AND METHODS: Forty-three flow density areas of 11 eyes with CNV were evaluated before and after treatment in this observational case series. Four cases were CNV type 1 and seven were CNV type 2. All the patients were evaluated by a spectral-domain OCT system. The scans were registered at baseline before injection, between 6 days and 14 days after injection, and monthly thereafter. The dark halo was automated assessed by Image J software. RESULTS: The authors observed a fluctuation of the dark halo around the CNV, the dark halo being larger in 95.4% of the cases before treatment and decreasing after injection. Correspondingly, the mean CNV area decreased in 83.7% of the cases after injection. The mean CNV area before treatment was 0.44 mm 2 (± 0.40 mm 2 ) and 0.34 mm 2 (± 0.29 mm 2 ) after treatment. The dark halo mean area before treatment was 0.34 mm 2 (± 0.27 mm 2 ) and 0.25 mm 2 (± 0.23 mm 2 ) after treatment. CNV area and dark halo area reductions after injection were statistically significant (P < .001). CNV-to-halo ratio was statistically significant, decreasing after injection (P < .001). CONCLUSIONS: OCTA is a noninvasive vascular imaging tool able to detect CNV flow and features. OCTA is also suitable to highlight choriocapillaris vascular density changes around neovascularization after treatment. The dark halo around CNV seen by OCTA showed a fluctuation after anti-VEGF treatment. These results might be useful in clinical practice.