Effect of Photodynamic Therapy on Optical Coherence Tomography Angiography in Eyes with Chronic Central Serous Chorioretinopathy

Purpose: To analyze the use of optical coherence tomography angiography (OCTA) in order to observe the changes in chronic central serous chorioretinopathy (CCSC) after half-dose photodynamic therapy (PDT). Methods: This is a retrospective study evaluating an imaging technique in a cohort of patients. Fundus photography, fluorescein angiography (FA), indocyanine green angiography (ICGA) (Heidelberg Spectralis, Heidelberg, Germany), OCT, and OCTA with the split-spectrum amplitude-decorrelation angiography algorithm (XR Optovue, Fremont, CA, USA) were performed prior to half-dose PDT. OCT and OCTA were conducted at week 1, month 1, month 2, and month 3 after half-dose PDT. Results: A total of 33 eyes of 28 patients were enrolled in the study. At the baseline assessment, the patient pool had a mean best-correct visual acuity of logMAR 0.29 ± 0.34 and the mean choroidal thickness was 407.45 ± 77.98 µm. At month 3 after PDT, the patient pool had a mean best-correct visual acuity of logMAR 0.1 ± 0.17 and the mean choroidal thickness was 355.48 ± 67.90 µm. Abnormal flow in the choriocapillary, which corresponded to the initial examinations using OCTA, was observed in all 33 eyes (100%). The images show an irregular high pixel values interval from low pixel values. At week 1 after half-dose PDT, 25 eyes (75.8%) resembled the baseline images of the choriocapillary layer of OCTA. Areas of nonperfusion in the choriocapillary were observed in 5 eyes (15.2%), and vessel-like material in the choriocapillary was observed in 3 eyes (9.0%). At month 3 after PDT, the choriocapillary layer of OCTA was shown to return to normal in 32 eyes (97%). Conclusions: We have detected choriocapillary changes in patients diagnosed with CCSC following half-dose PDT by using noninvasive OCTA. These findings provide new evidence in support of the previously proposed hypothesis on the effect of PDT and suggest that OCTA may become a useful tool in the follow-up of CCSC.