PURPOSE: To compare the efficacy and safety of half-dose and one-third-dose photodynamic therapy (PDT) with verteporfin in patients with chronic central serous chorioretinopathy (CSC). METHODS: This retrospective study included 72 eyes from 72 patients with chronic CSC treated with either one-third-dose (2 mg/m²) or half-dose (3 mg/m²) PDT. Best-corrected visual acuity (BCVA), central retinal thickness (CRT), subretinal fluid (SRF) thickness, subfoveal choroidal thickness (SFCT), and optical coherence tomography (OCT) features were evaluated at baseline, 3 months, and 12 months. Fluorescein angiography (FA) was used to guide laser application. Treatment outcomes, including SRF resolution, BCVA gain, and recurrence rates, were compared between the two groups. RESULTS: At 12 months, complete SRF resolution was achieved in 40 eyes (78.4%) in the half-dose group and 15 eyes (71.4%) in the one-third-dose group. The recurrence rate of SRF was significantly higher in the one-third-dose group (20%) compared to the half-dose group (7.5%) (P =.015). BCVA improved significantly in both groups, with mean increases from 72.4 ± 3.9 to 77.1 ± 5.6 letters in the one-third-dose group and from 74.4 ± 4.2 to 80.2 ± 2.19 letters in the half-dose group. The proportion of patients achieving a ≥ 10-letter gain was higher in the half-dose group (52%) compared to the one-third-dose group (28.5%, P =.001). Both groups exhibited significant reductions in CRT, SRF thickness, and SFCT (P <.001), with no significant intergroup differences. Baseline CRT and fluorescein leakage patterns influenced treatment response. CONCLUSIONS: Both one-third-dose and half-dose PDT effectively improved visual and anatomical outcomes in patients with chronic CSC. However, half-dose PDT demonstrated superior efficacy in achieving SRF resolution and greater visual acuity gains with a lower recurrence rate. CLINICAL TRIAL NUMBER: Not applicable.