Anterior Suprachoroidal Fluid Following Photodynamic Therapy for Chronic CSC: An Anterior-Segment Optical Coherence Tomography Study

INTRODUCTION: The early anterior uveal response after photodynamic therapy (PDT) in chronic central serous chorioretinopathy (CSC) has not been systematically characterized. This study aimed to determine the incidence of anterior supraciliary/suprachoroidal fluid (SCF) detected by anterior-segment optical coherence tomography (AS-OCT) after half-fluence PDT and to examine its association with macular and choroidal structural changes. METHODS: In this retrospective single-center case series, 29 eyes of 29 patients with chronic CSC treated with half-fluence PDT were analyzed. AS-OCT and macular OCT were obtained at baseline and day 3, and 1 month. Eyes were classified as SCF-change (new or increased SCF at day 3) or SCF-stable. The primary outcome was the incidence of SCF at day 3. Secondary outcomes included best-corrected visual acuity (BCVA), central macular thickness (CMT), central choroidal thickness (CCT), and the incidence of PDT-induced acute exudative maculopathy (PAEM). Continuous variables are presented as median [interquartile range], and nonparametric statistical tests were used. RESULTS: SCF was detected in 4/29 eyes (13.8%) at baseline and in 14/29 eyes (48.3%) at day 3. Eleven eyes (37.9%) were classified as SCF-change and 18 (62.1%) as SCF-stable. In the SCF-change group, CMT increased significantly from 366.0 [237.0, 405.0] μm at baseline to 490.0 [263.0, 691.5] μm at day 3 (p = 0.002). In contrast, the SCF-stable group showed no significant change. The magnitude of CMT increase was significantly greater in the SCF-change group (p = 0.003). PAEM occurred more frequently in the SCF-change group than in the SCF-stable group (7/11 vs. 2/18; Fisher's exact test, p = 0.010; odds ratio 14.0, 95% confidence interval 2.06-95.09). CONCLUSIONS: Anterior SCF frequently appeared in the early phase after PDT for chronic CSC and was associated with greater short-term increases in macular thickness and a higher incidence of PAEM. Detection of anterior SCF by AS-OCT may provide a useful early imaging marker reflecting acute choroidal reactivity following PDT.