Longitudinal Changes in Scleral Thickness after Half-dose Photodynamic Therapy in Central Serous Chorioretinopathy

PURPOSE: To evaluate longitudinal changes in scleral thickness after half-dose photodynamic therapy (PDT) in eyes with central serous chorioretinopathy (CSC) in parallel with widefield assessment of choroidal thickness. METHODS: This retrospective observational study included 41 eyes of 41 patients with unilateral CSC who underwent half-dose PDT for persistent subretinal fluid and completed 12 months of follow-up. Scleral thickness was measured in 4 quadrants using anterior-segment optical coherence tomography (OCT) at baseline and at 3 and 12 months after PDT. Widefield choroidal thickness was assessed using widefield swept-source OCT with an 18-mm grid divided into 9 sectors. Untreated fellow eyes served as a reference group. RESULTS: In treated eyes, widefield choroidal thickness decreased significantly at 3 months after PDT across all 9 predefined sectors (all P < 0.05) and remained reduced at 12 months, with no significant differences between 3 and 12 months. In untreated fellow eyes, no consistent longitudinal changes in choroidal thickness were observed; however, a statistically significant reduction was noted only in the outer superonasal sector at 3 months (P = 0.015). In contrast, scleral thickness showed no significant changes at any time point in either treated or fellow eyes (all P > 0.05). CONCLUSIONS: Despite widespread and sustained choroidal thinning after half-dose PDT, scleral thickness remained unchanged for at least 12 months in eyes with CSC. These findings suggest that scleral thickening in CSC is unlikely to represent a readily reversible response to treatment-associated choroidal changes and may instead reflect a relatively stable anatomical feature.