To compare changes in choroidal hyperpermeability after half-energy photodynamic therapy (PDT) and intravitreal ranibizumab in the treatment of chronic central serous chorioretinopathy (CSC).

Post-hoc analysis was performed in a randomized, controlled trial comparing half-energy PDT versus intravitreal ranibizumab for chronic CSC; during the experiments, the other treatment was available for salvage treatment if the original was unsuccessful at 3 months. A commercially available image analysis program (Adobe® Photoshop® CS6 [Adobe Systems, Inc., San Jose, CA]) was used for quantification of change in choriodal hyperpermeability on indocyanine green angiography after half-energy PDT or three consecutive intravitreal injections of ranibizumab. Post-treatment images were subtracted from pre-treatment images after adjustments were made to create images depicting the change in choroidal hyperpermeability with treatment. Integrated gray scale values per area in this image were used for analysis of change in choroidal hyperpermeability.

The calculated change in choroidal hyperpermeability was significantly greater in the half-energy PDT group (17.36 ± 8.74) than in the ranibizumab group (6.78 ± 5.03) ( p < 0.001). All eyes in the half-energy PDT group showed complete resolution of subretinal fluid, and no significant difference in change of choroidal hyperpermeability was found in eyes that received half-energy PDT as primary or salvage treatment. In the ranibizumab-treated group, subretinal fluid resolution was accomplished in 5 eyes, and these eyes showed a significantly larger decrease in choroidal hyperpermeability when compared with eyes showing poor response (10.31 ± 4.00 vs. 2.74 ± 2.16, p = 0.005). In the successfully treated eyes with ranibizumab, there was no significant difference in choroidal hypopermeability change when compared to half-energy PDT ( p = 0.124).

Using our novel method of analysis of change in choroidal hyperpermeability following treatment for chronic CSC, greater change was found in eyes with good response, and the superior outcome of half-energy PDT over ranibizumab may be attributed to greater influence on choroidal hyperpermeability.