Multimodal Imaging and Choroidal Volumetric Changes after Half-fluence PDT in Central Serous Chorioretinopathy

Purpose: The purpose of this study was to identify SD-OCT changes that correspond to leakage on fluorescein (FA) and indocyanine angiography (ICGA) and evaluate effect of half-fluence photodynamic therapy (PDT) on choroidal volume in chronic central serous choroidoretinopathy (CSC).Methods: Retrospective analysis of patients with chronic CSC who had undergone PDT. Baseline FA and ICGA images were overlaid on SD-OCT to identify OCT correlates of FA or ICGA hyperfluorescence. Choroidal volume was evaluated in a subgroup of eyes before and after PDT.Results: Twenty eyes were evaluated at baseline, of which seven eyes had choroidal volume evaluations at baseline and 3 months following PDT. SD-OCT changes corresponding to FA hyperfluorescence were subretinal fluid (73%), RPE microrip (50%), RPE double-layer sign (31%), RPE detachment (15%), and RPE thickening (8%). ICGA hyperfluoresence was correlated in 93% with hyperreflective spots in the superficial choroid. Choroidal volume decreased from 9.35 ± 1.99 to 8.52 ± 1.92 and 8.04 ± 1.7 mm³ (at 1 and 3 months post PDT, respectively, p ≤ 0.001).Conclusions: We identified specific OCT findings that correlate with FA and ICGA leakage sites. SD-OCT is a valuable tool to localize CSC lesions and may be useful to guide PDT treatment. Generalized choroidal volume decrease occurs following PDT and extends beyond PDT treatment site.