Abstract
PURPOSE: This study evaluates the effectiveness and safety of multiple PDT sessions for cases of persistent and recurrent subretinal fluid (SRF) in chronic central serous chorioretinopathy (CSC). METHODS: This multicentre, retrospective cohort study included patients aged ≥18 years with chronic CSC who received at least two sessions of PDT at Amsterdam University Medical Center or Leiden University Medical Center between August 2009 and February 2025. Outcomes included the resolution of SRF, changes in visual acuity (VA), subfoveal choroidal thickness (SFCT) and continuity of the external limiting membrane (ELM) and ellipsoid zone (EZ). RESULTS: The study included 88 patients with chronic CSC, of whom 88.6% were male. Of the 105 eyes treated, 62.5% had persistent SRF after the first PDT, while 37.5% achieved complete SRF resolution. After the second PDT, SRF resolved completely in 62.8% of eyes overall, with 53.1% in the persistent SRF group and 64.1% in the recurrent SRF group. Following the third PDT, 67.7% of patients showed complete SRF resolution. VA improved by 3 ± 2 letters (p = 0.033) above baseline after the second PDT, with the recurrent SRF group showing greater improvements. SFCT was lower than baseline after PDT treatments in both groups. ELM and EZ continuity also generally showed improvements on optical coherence tomography, particularly in the recurrent SRF group, suggesting retinal integrity restoration rather than atrophic changes. CONCLUSION: Repeated PDT is an effective and safe treatment for both persistent and recurrent chronic CSC, with improvements in SRF, VA, SFCT and retinal layer continuity.