Evaluation of choriocapillaris perfusion changes in chronic central serous chorioretinopathy following Half-Dose photodynamic therapy

Background: This study aimed to evaluate changes in choriocapillaris (CC) perfusion in patients with chronic central serous chorioretinopathy (cCSC) following treatment with half-dose photodynamic therapy (PDT), using swept-source optical coherence tomography angiography (SS-OCTA). Methods: This pilot study included patients diagnosed with cCSC who underwent half-dose PDT using the Visulas 690s PDT Laser System (Carl Zeiss Meditec, Inc., Jena, Germany; 689-nm wavelength, 50J/cm², 83s). Fovea-centered OCTA scans (6 × 6mm) were obtained using the Zeiss Plex Elite 9000 SS-OCT system. OCTA assessments were conducted at baseline prior to treatment and 6 months post-treatment. The primary outcome was the percentage of choriocapillaris flow deficits (FD%) on OCTA. Secondary outcomes included best-corrected visual acuity (BCVA), central macular thickness (CMT), and subfoveal choroidal thickness (SFCT). Results: The study included 23 eyes from 23 patients with cCSC, with a mean age of 46.3 ± 2.1 years, of which 16 out of 23 were men. Significant improvements were observed in all parameters at 6 months. The FD% decreased significantly from 28.9 ± 2.2% at baseline to 26.4 ± 1.9% after 6 months (p = 0.023). BCVA improved from 0.28 ± 0.13 LogMAR to 0.22 ± 0.11 LogMAR (p = 0.025). Both CMT and SFCT showed significant reductions (p < 0.05). After 6-months, SRF was resolved in 21 out of 23 eyes (91.3%) included in the analysis, while the remaining two eyes showed a reduction of SRF. Conclusion: Half-dose PDT was effective in improving CC perfusion and other morpho-functional parameters in eyes with cCSC. These findings provide valuable insights into the potential mechanisms through which PDT may influence the progression of cCSC.