Aims To quantify the changes of the choroidal structure in the enhanced depth imaging optical coherence tomographic (EDI-OCT) images after intravitreal aflibercept (IVA) injections for polypoidal choroidal vasculopathy (PCV).

Methods Retrospective, observational case series. Forty eyes of 40 treatment-naive patients who underwent IVA for PCV were examined by EDI-OCT before, and 3 months and 12 months after IVA. The EDI-OCT images were binarised by ImageJ software. The cross-sectional luminal and stromal areas of the inner and outer subfoveal choroid of 1500 µm width were quantified.

Results The stromal but not the luminal area of the inner choroid was significantly decreased at 3 months and 12 months after the IVA (stromal area, both p<0.001; luminal area, both p>0.050). On the other hand, the luminal but not the stromal area of the outer choroid was significantly decreased at 3 months and 12 months (luminal area, both p<0.001; stromal area, both p>0.050). The Pachychoroid Index, ratio of luminal/stromal area (L/S ratio) of the outer choroid divided by the L/S ratio of the inner choroid, was significantly decreased at 3 months and 12 months (both p<0.050). The Pachychoroid Index was increased and returned almost to the baseline level after recurrences and decreased again after successful re-treatment. The baseline Pachychoroid Index was significantly correlated with the presence of a dry macula, thinner fovea and better visual acuity at 12 months (all p<0.050).

Conclusion The binarisation of the EDI-OCT images can be used to quantify the activity of PCV and to predict the prognosis after IVA.