Extensive reduction in choroidal thickness after photodynamic therapy in eyes with central serous chorioretinopathy

We examined the effect of reduced fluence (rf)-photodynamic therapy (PDT) of the macular area on the wide-field choroidal thickness in 20 eyes with central serous chorioretinopathy (CSC) and 20 age- and sex-matched control eyes. The choroidal thickness at the posterior pole was measured before and after rf-PDT, using a grid with inner and outer rings, each divided into superotemporal, inferotemporal, superonasal, and inferonasal quadrants, respectively, making up a total of nine subfields including the central 3 mm ring. Before treatment, all eyes showed wide-field choroidal thickening from the dilated vortex vein ampulla to the fovea, along the course of the vein. After rf-PDT of the macular area, the choroidal thickness significantly decreased, not only in the irradiated macular area but also outside the arcade vessels in all quadrants (p 0.05 for all subfields). These findings provide new insights into the pathogenesis of CSC and explain the reasons for the effectiveness of rf-PDT for this condition.