Comparison of visual and anatomical outcomes of half-fluence and half-dose photodynamic therapy in eyes with chronic central serous chorioretinopathy

To compare visual and anatomical outcomes of half-fluence (HF) and half-dose (HD) photodynamic therapy (PDT) in chronic central serous chorioretinopathy (CSC). Particular focus was given to photoreceptor recovery rate following treatment.

Retrospective review of 52 chronic CSC patients who underwent HF- or HD-PDT (26 patients per group). Best-corrected visual acuity and spectral-domain optical coherence tomography findings were compared between groups.

Average follow-up for HF- and HD-PDT was 20.7 ± 7.2 and 22.3 ± 6.1 months respectively. Both groups had significant visual acuity improvements, as well as central foveal and subfoveal choroidal thickness reductions. Measured parameters were not significantly different between groups at any time point examined. Complete photoreceptor recovery, defined as a continuous ellipsoid zone with a discernible interdigitation zone, was observed at 12 months in 19 (73 %) and 14 patients (54 %) in the HF- and HD-PDT groups respectively (p = 0.150). Overall photoreceptor recovery rate was not different between groups (p = 0.301, log-rank test). Delayed (>12 months) photoreceptor recovery was significantly associated with baseline external limiting membrane disruption (OR: 21.7, 95 % CI: 1.7–285.4, p = 0.019), disease duration (years, OR: 1.9, 95 % CI: 1.2–3.0, p = 0.005), and fovea-to-PDT spot center distance (100 μm unit, OR: 0.74, 95 % CI 0.56–0.97, p = 0.027). However, delayed photoreceptor recovery was not significantly associated with PDT modality.

Both HF- and HD-PDT are effective in treating chronic CSC. No significant differences in visual or anatomical outcomes were observed.