Structural analyses of choroid after half-dose verteporfin photodynamic therapy for central serous chorioretinopathy

Background/aims To investigate the changes in the intrachoroidal structures after half-dose verteporfin photodynamic therapy (PDT) for central serous chorioretinopathy (CSC). Methods Swept-source optical coherence tomography cross-sectional images of 22 eyes of 22 patients with CSC were retrospectively analysed by a manual delineation technique and binarisation method. Results In the 22 eyes, the mean subfoveal choroidal thickness decreased from 412.9 +/- 112.9 mu m at baseline to 340.0 +/- 111.0 mu m at 3 months (p< 0.0001). The mean thickness of the large choroidal vessel layer decreased from 368.7 +/- 112.7 mu m at baseline to 292.2 +/- 118.0 mu m at 3 months (p< 0.0001), but the mean choriocapillarismedium choroidal vessel layer thickness did not change from 44.2 +/- 29.2 mu m at baseline to 47.8 +/- 25.7 mu m at 3 months (p= 0.85). Analyses of the binarised choroidal images showed that a 3 mm subfoveal choroidal area decreased from 1.141 +/- 0.290 mm(2) at baseline to 0.962 +/- 0.320 mm(2) at 3 months after PDT (p= 0.0001). The mean luminal areas decreased from 0.826 +/- 0.246 mm(2) at baseline to 0.665 +/- 0.234 mm(2) at 3 months (p= 0.0001), however, the mean stromal areas did not change from 0.315 +/- 0.066 mm(2) at baseline to 0.297 +/- 0.095 mm(2) at 3 months (p= 0.60). Conclusions Half-dose PDT reduces subfoveal choroidal thickness and alters the intrachoroidal structures in eyes with CSC.