Study of vessel density by optical coherence tomography angiography in patients with central serous chorioretinopathy after low-fluence photodynamic therapy

Background: To perform a quantitative analysis of retinal and choriocapillaris vessel density (VD) in patients with central serous chorioretinopathy (CSC) after low-fluence verteporfin photodynamic therapy (vPDT), using Optical Coherence Tomography Angiography (OCTA). Methods: A total of 28 eyes of 27 patients with CSC (21 females, 6 males, mean age 47 ± 11 years) were included in this retrospective study. At baseline and after 6 months after vPDT, we evaluated VD of the superficial capillary plexus (SCP), the deep capillary plexus (DCP) and the choriocapillaris (CC) in different macular areas (whole image, parafovea and fovea). We also analyzed the central foveal thickness (CFT) and subfoveal choroidal thickness (SFCT) with Enhanced Depth Imaging-Optical Coherence Tomography (EDI−OCT). Results: Eighteen eyes and ten eyes were responders and non responders to low-fluence vPDT, respectively. The responders group showed a significant increase in VD in DCP and CC after treatment (p < 0.05). In the non responders group the VD in SCP, DCP and CC did not differ before and after treatment. We also found a significant correlation in responders group between Best-Corrected Visual Acuity (BCVA) and CFT (r = 0.566; p = 0.014) and between BCVA and the increased VD of CC (r= -0.559; p = 0.016). In non responders group, the correlation between OCT, OCTA parameters and BCVA was not statistically significant. Conclusions: OCTA allowed us to enhance our knowledge regarding the pathophysiology of vascular changes in retinal and CC networks after low-fluence vPDT. OCTA may represent a new biomarker to evaluate the efficacy of low-fluence vPDT in the treatment of CSC.