IMPORTANCE A randomized clinical trial is needed to evaluate what is the best photodynamic therapy (PDT) protocol to use for acute central serous chorioretinopathy. OBJECTIVE To compare the efficacy and safety of a 50% dose of verteporfin (a method of PDT) with the efficacy and safety of a 30% dose for acute central serous chorioretinopathy. DESIGN, SETTING, AND PARTICIPANTS A multicenter, noninferiority, double-masked, randomized, controlled, clinical trial in which 131 patients (131 eyes) with acute central serous chorioretinopathy for less than 6 months were recruited with a follow-up of 12 months from university-based ophthalmology practices. INTERVENTIONS Patients were randomly assigned to either a 50% dose of verteporfin (the 50%-dose PDT group) or a 30% dose (the 30%-dose PDT group). MAIN OUTCOMES AND MEASURES The 2 primary outcome measures were the proportion of eyes with complete absorption of subretinal fluid and the proportion of eyes with complete disappearance of fluorescein leakage at 6 and 12 months. The secondary outcome measures included the subretinal fluid recurrent rate, the fluorescein leakage recurrent rate at 12 months, the mean best-corrected visual acuity, the retinal thickness of the foveal center, and the maximum retinal thickness at each scheduled visit. RESULTS The noninferiority of the 30%-dose PDT compared with the 50%-dose PDT for the primary outcomes was not demonstrated. The optical coherence tomography-based improvement rate in the 30%-dose PDT group was less than that in the 50%-dose PDT group both at 6 months (73.8% vs 92.9%; alpha = 0.0125, P = .006) and at 12 months (75.4% vs 94.6%; alpha = 0.0125, P = .004). The fluorescein angiography-based improvement rate in the 30%-dose PDT group was less than that in the 50%-dose PDT group both at 6 months (68.9% vs 91.1%; alpha = 0.0125, P = .003) and at 12 months (68.9% vs 92.9%; alpha = 0.0125, P = .001). The subretinal fluid recurrence rate in the 30%-dose PDT group was greater than that in the 50%-dose PDT group (24.0% vs 5.7% at 12 months; P = .010, determined by use of the log-rank test). The fluorescein leakage recurrent rate in the 30%-dose PDT group was significantly higher than that in the 50%-dose PDT group (16.7% vs 3.8% at 12 months; P = .03, determined by use of the log-rank test). No ocular adverse event was encountered in the study. CONCLUSIONS AND RELEVANCE A 50% dose of verteporfinmay be more effective at resolving subretinal fluid and fluorescein leakage, and with better visual outcomes, than a 30% dose for acute central serous chorioretinopathy.