Background To evaluate the long-term efficacy and complications of half-dose photodynamic therapy (PDT) for treating chronic central serous chorioretinopathy (CSC).

Methods A retrospective, interventional case series of patients with chronic CSC (symptoms ≧3 months) receiving half-dose PDT (3 mg/m² verteporfin). Optical coherence tomography, fundus short-wave autofluorescence and near-infrared autofluorescence (SW-AF and NIR-AF) were taken at each visit. Central foveal thickness (CFT) and relative CFT (RCFT) were measured manually. Outcome measures included best-corrected visual acuity (BCVA), resolution of subretinal fluid (SRF), CFT and RCFT, and changes of SW-AF and NIR-AF.

Results 56 eyes of 56 patients (45 male and 11 female patients; mean age 45 years) were included in this study. The anatomic resolution was obtained in 100% at 1 year and at the last follow-up, respectively. Four cases developed recurrence of SRF after one session of PDT. The mean session of PDT was 1.00. The mean follow-up was 55.5 months. Final CFT and RCFT showed a positive correlation with final BCVA. Complications included enlargement of retinal pigment epithelial atrophy in one case and choroidal neovascularisation in another two cases at 12 and 14 months after PDT.

Conclusions PDT with half-dose verteporfin has a long-term efficacy and safety profile in chronic CSC. However, complications may still happen despite the reduced dosage.

Trial registration number The CCH IRB No. 131007.