[Changes in OCT Angiography of Type 2 CNV in Neovascular AMD during Anti-VEGF Treatment]

Purpose OCT-A is a new method to visualise the 2D and 3D structures of neovascular complexes in exudative AMD. The aim of the present study was to characterise type 2 CNV in different 2D segmentations and in 3D imaging and to investigate changes during anti-VEGF treatment. Methods 12 patients with type 2 CNV in FA and SD-OCT were selected. OCT-A (Avanti, Optovue) was obtained initially and after the first three injections and thereafter, if "new activity" (increase in sub- or intraretinal fluid) occurred. The characteristics of the type 2 CNV were classified initially and during follow-up in different segmentations (outer retina, RPE, CC, choroidea), in respect to the size of the CNV, the flow area within the CNV and flow index (% of flow area within the total lesion). Results Comparison of the vessel characteristics before and after anti-VEGF treatment showed a significant reduction in the size of CNV at every level (p < 0.05). This was most significant at the RPE level (p < 0.005). After new activity, a significant increase in size was only recognised at the CC level (p < 0.05). Similarly, the most significant changes in the flow area were measured at the RPE level before and after treatment (p < 0.01) and at the CC level after new activity (p < 0.05). Demarcation from type 2 CNV of the bordering tissue was much better when activity occurred. Conclusions OCT-A provides a new opportunity for the assessment of vascular characteristics of type 2 CNV, and quantifies CNV size and vascularisation under anti-VEGF therapy. This may be used in further studies in combination with SD-OCT scans to describe characteristics of this type of CNV under treatment. OCT-A is an additional medical imaging procedure to SD-OCT and FA, but more experience is needed in distinguishing CNV in the active and non-active stages.