Functional and Structural Outcomes of Photodynamic Therapy (PDT) With or Without Eplerenone for Central Serous Chorioretinopathy.

Background/Objectives: To evaluate whether the combination of oral eplerenone and half-dose full-fluence photodynamic therapy (HD-FF PDT) provides greater efficacy than HD-FF PDT alone in persistent central serous chorioretinopathy (CSCR). Methods: This monocentric, retrospective, observational study included patients with persistent (>6 months) simple or complex CSCR who had previously undergone either half-dose full-fluence photodynamic therapy (HD-FF PDT) alone or HD-FF PDT combined with oral eplerenone as part of routine clinical practice between September 2024 and March 2025. Functional and morphological data collected at baseline and at 1, 3, and 6 months after treatment were retrospectively reviewed. An artificial intelligence-based algorithm was used to analyze OCT scans, quantifying subretinal and intraretinal fluid volumes (SRFV, IRFV) and assessing ellipsoid zone and external limiting membrane integrity, hyperreflective foci, subfoveal choroidal thickness (SCT), and central macular thickness (CMT). Results: Fifty patients (53 eyes; mean age 52 years) were included, with no significant baseline differences between groups. Best-corrected visual acuity improved more significantly in Group B at 1 and 6 months (p = 0.032 and p = 0.009, respectively). At 6 months, subretinal fluid volume (SRFV), quantified by AI-based OCT analysis, was significantly lower in the combined therapy group (p = 0.014). An AI-defined complete resolution of subretinal fluid (SRFV < 0.010 mm3) was achieved more frequently in Group B than in Group A (77% vs. 22%, p = 0.001). Conclusions: Although HD-FF PDT remains the standard treatment for persistent CSCR, adjunctive therapy with the mineralocorticoid receptor antagonist eplerenone may enhance subretinal fluid reabsorption and improve mid-term anatomical and functional outcomes.