Structural and vascular changes of the choroid in polypoidal choroidal vasculopathy after intravitreal anti-VEGF therapy

Introduction: To identify the changes in vessel density (VD) of choriocapillaris (CC) and in subfoveal choroidal thickness (SFCT) and to evaluate their correlation with functional response after three monthly intravitreal injections of Ranibizumab (loading phase) in patients affected by Polypoidal Choroidal Vasculopathy (PCV). Methods: A total of 30 eyes of 30 PCV patients and 30 eyes of 30 healthy subjects as control group were enrolled in this prospective study. The best corrected visual acuity (BCVA) was measured at baseline and after one month from third intravitreal injections in each patient. The VD of CC was evaluated in macular area by means of Optical Coherence Tomography Angiography (OCTA). Central macular thickness (CMT) and SFCT were analyzed by Enhanced Depth Imaging (EDI)-OCT. Results: The VD of CC showed statistically lower values in PCV patients at baseline respect to after loading phase (LP) and normal eyes (p<0.001). CMT and SFCT revealed a statistically significant reduction after LP (p<0.001). Multiple regression analysis revealed a significant negative correlation between the reduced SFCT, CMT at baseline and the improvement of BCVA after LP (p<0.05). Conclusion: The close relationship between the thinner SFCT and better visual outcome after LP reveals the role of the EDI-OCT assessment of choroid as predictive biomarker of functional response to anti-VEGF therapy. This tool could provide a quantitative evaluation of structural features of choroid avoiding mistakes of evaluation at OCTA.