The blood flow characteristics of polypoidal choroidal vasculopathy and the choroidal remodelling process after photodynamic therapy.

OBJECTIVES:To investigate the blood flow characteristics of polypoidal choroidal vasculopathy (PCV) using optical coherence tomography angiography (OCTA) and to analyse photodynamic therapy (PDT) effects on choroidal remodelling in PCV. MATERIALS AND METHODS:Diagnostic indocyanine green angiography and OCTA were performed. All patients underwent PDT with full-dose verteporfin and were followed up with enhanced-depth imaging optical coherence tomography. RESULTS:At baseline, a branching vascular network (BVN) was clearly demonstrated in all patients with PCV who underwent OCTA examinations as opposed to polyps. Additionally, the choroidal thickness (266 [range: 74-456] µm) showed a positive relationship with polyp size (0.59 [range: 0.33-0.94] mm2 , r = 0.679, P = 0.0022). The subfoveal choroidal thickness and choroidal thickness at polyp sites increased within 1 day after PDT and atrophied 1-3 months after PDT. CONCLUSIONS:The differences in imaging characteristics between BVNs and polyps on OCTA were presumably due to both blood turbulence (different flow orientations) within polyps and the velocities detectable on OCTA. Moreover, the choroidal remodelling effects of PDT in PCV suggested the occurrence of transitional reactive inflammatory choroidal vascular hyperpermeability and choroidal exudation. PCV involved the entire choroids rather than only focal lesions. Lasers Surg. Med. 50:427-432, 2018. © 2018 Wiley Periodicals, Inc.