Optical coherence tomography angiography can separately detect the superficial vascular and the deep vascular networks. These networks are overlaid and seem to be fused when seen with standard angiographies. Furthermore, optical coherence tomography angiography technology allows for the visualization of abnormal blood column and vessel wall details.

Purpose To use optical coherence tomography (OCT) angiography to monitor the short-term blood flow changes in choroidal neovascularization (CNV) in response to treatment. Participants One patient with exudative age-related macular degeneration (AMD) Methods In this retrospective report, a case of CNV was followed closely with OCT angiography over 3 cycles of anti-angiogenic treatment. Outer retinal flow index, CNV flow area and central macular retinal thickness were measured. Results Quantitative measurements of CNV flow area and flow index showed rapid shutdown of flow over the initial 2 week, followed by re-appearance of CNV channel by the 4th week, preceding fluid re-accumulation at 6 weeks. Conclusions Frequent OCT angiography reveals a previously unknown pattern of rapid shutdown and re-appearance of CNV channels within treatment cycles. OCT angiographic changes precede fluid re-accumulation and could be useful as leading indicators of CNV activity that could guide treatment timing. Further studies using OCT angiography in short intervals between anti-angiogenic treatments are needed.

This study suggests that OCT-A is able to detect the Type 2 CNV developments. This new method allows noninvasive analysis of CNV networks remodeling during anti-vascular endothelial growth factor follow-up. In conclusion, OCT-A provides a useful approach for monitoring the CNV Type 2 over the time.

Optovue AngioVue system technology for optical coherence tomography (OCT) angiography is based on the AngioVue Imaging System (Optovue, Inc., Freemont, CA), using split-spectrum amplitude-decorrelation angiography (SSADA) algorithm. This algorithm was developed to minimize scanning time. It detects motion in blood vessel lumen by measuring the variation in reflected OCT signal amplitude between consecutive cross-sectional scans. The novelty of SSADA lies in how the OCT signal is processed to enhance flow detection and reject axial bulk motion noise. Specifically, the algorithm splits the OCT image into different spectral bands, thus increasing the number of usable image frames. Each new frame has a lower axial resolution that is less susceptible to axial eye motion caused by blood pulsation. Optovue AngioVue system technology allows quantitative analysis. It provides numerical data about flow area and non-flow area. It can also generate a flow density map. These metrics may serve as biomarkers in diagnosis and for tracking disease progression or treatment response. Flow area: the software will calculate the drawn area and vessel area in mm(2). It allows for comparison of all measurements for a given participant. Non-flow area: the software shows the non-perfused areas by mouse click selection. Ischemic areas will be shown in yellow. These areas may be saved and matched with others in the study. Flow density tool is able to measure the percentage of vascular areas on en face angiograms. This analysis is based on an ETDRS grid centered on the macula as with the thickness map. This tool works both on inner and outer vascular plexus.

In the authors’ 10 cases of branch retinal vein occlusion, OCT angiography (OCT-A) shows diffuse vascular anomalies both in the superficial and deep vascular network. Fovea avascular zone (FAZ) enlargement, capillary non-perfusion (CN-P) and microvascular abnormalities (MA) are well characterized by OCT-A in all eyes.