Vascular and structural alterations of the choroid evaluated by optical coherence tomography angiography and optical coherence tomography after half-fluence photodynamic therapy in chronic central serous chorioretinopathy

Abstract

To concurrently evaluate the effect of half-fluence photodynamic therapy (hf PDT) on choriocapillaris (CC) perfusion and choroidal structure in chronic central serous chorioretinopathy (CSC). This prospective study included 48 eyes of 41 patients with chronic CSC. Enhanced depth imaging optical coherence tomography and optical coherence tomography angiography (OCTA) images were analyzed. Choroidal area (CA), luminal area (LA), and stromal area (SA) were computed using Image J software. One month after hf-PDT, total CA decreased to 1.312mm2 from 1.490mm2 (p < 0.001), LA decreased to 0.981mm2 from 1.097mm2 (p < 0.001), and SA decreased to 0.331mm2 from 0.393mm2 (p < 0.001). In OCTA, the CC flow in the eyes with CSC (17.75mm2) was statistically significantly lower than the fellow eyes (18.93mm2) at the baseline visit (p < 0.001). After hf-PDT, the flow in the choriocapillaris statistically significantly increased to 18.81mm2 at the first month (p = 0.02). OCTA proves that after hf-PDT a significant increase in CC perfusion occurred at first month. The decrease of the luminal areas in enhanced depth imaging optical coherence tomography is mainly due to a decrease in large-caliber vessels, which indicates that hf-PDT has an effect on larger choroidal vessels and spares CC flow.