ObjectiveTo evaluate the efficacy and safety of half-dose verteporfin photodynamic therapy (PDT) for chronic central serous chorioretinopathy (CSC). Methods35 eyes (35 patients) with chronic (or recurrent) CSC treated with half-dose verteporfin PDT. Best-corrected visual acuity(BCVA), central macular thickness (CMT) were measured before and after treatment (1, 3 and 6 months). The mean BCVA was 0.28±0.22, mean CMT was(384.5±85.0)μm. The situation of subretinal fluids (SRF) absorption was observed. ResultsIn 35 eyes, SRF of 29 eyes (82.9%) completely absorbed and 6 eyes (17.1%) not completely absorbed after one month of treatment. SRF of all eyes (100.0%) completely absorbed after three months of treatment. After 6 months of treatment, SRF of 3 eyes (8.6%) were recurrence, which might be completely absorbed when a half-dose maintenance therapy PDT was used again. The mean BCVA significantly improved to 0.14±0.13 at 1 months, 0.05±0.11 at 3 months and 0.05±0.12 at 6 months after PDT (t=5.410, 7.830, 7.758; P < 0.05). The mean CMT decreased to (224.3±61.4) μm at 1 months, (199.6±32.7) μm at 3 months and (205.3±39.6) μm at 6 months after PDT (t=11.856, 11.781, 11.900; P < 0.05). The mean CMT of controlled 32 eyes after treatment was (198.5±33.9) μm, much lower than the fellow eyes(232.3±17.5) μm (t=-3.988, P < 0.05). ConclusionsHalf-dose verteporfin PDT was safe and effective in treating chronic CSC, but may cause thinning of CMT.