Utility of an additional photodynamic therapy session after multiple failed PDT treatments in chronic central serous chorioretinopathy

•Despite multiple previous photodynamic therapy failures, trying again may be useful.•The response to photodynamic therapy was greater in patients who presented choriocapillaris occlusion 3 days after treatment.•There were no additional complications or loss of visual acuity due to retreatment. To assess the efficacy of an additional photodynamic therapy (PDT) in chronic central serous chorioretinopathy (cCSCR) patients who have two or more previous failed PDTs. Ten eyes of 10 patients with cCSCR who had received two or more PDTs without complete resolution of the subretinal fluid (SRF) or with early recurrence (before 3 months) were included. An additional half-fluence PDT was performed. Swept-source optical coherence tomography (OCT) and OCT angiography were performed before, 3 days, 1 month, 3 months, 6 months and 12 months after treatment. Age, gender, best-corrected visual acuity (BCVA), subfoveal choroidal thickness, SRF and vessel occlusion in the choriocapillaris (CC) were collected. The median number of previous PDTs was 3 (range 2 to 4). BCVA before and 12 months after treatment was 72 letters (50 to 95) and 78 letters (55 to 100) (p=0.094). Median initial SRF was 94 µm (50 to 306), being 0 µm (range 0 to 81) at the end of the follow-up (p=0.007). After the additional PDT, 8 out of 10 patients had a complete SRF resorption. All the patients except one who had a complete response (7/8) had an occlusion in the CC 3 days after PDT. Despite previous failed PDTs in cCSCR, good anatomical results can be achieved, this being more likely if an early vessel occlusion in the CC is observed. Even when the BCVA did not improve, the high rate of fluid resolution could justify the additional PDT treatment in order to maintain visual function.