AIM:By analyzing optical coherence tomography angiography(OCTA)characteristics of central serous chorioretinopathy(CSC)and comparing the differences of CSC between OCTA and indocyanine green angiography(ICGA), to explore if OCTA can substitute ICGA for diagnosis of CSC patients, and guide the treatment of photodynamic therapy(PDT).

METHODS: We reviewed 30 eyes of 30 patients with CSC, who were diagnosed by fluorescein angiography(FFA)and ICGA at Beijing Tongren Eye Center from November 2015 to March 2016. All patients underwent best-corrected visual acuity(BCVA)measurement, intraocular pressure, slit-lamp examination, indirect ophthalmoscope, color fundus photography, FFA, ICGA and OCTA. FFA and ICGA were captured by Spectralis HRA + OCT(Spectralis HRA + OCT^®; Heidelberg Engineering, Heidelberg, Germany). OCTA was performed by RTVue XR Avanti device(OptovueInc, Fremont, CA)with 6mm×6mm Angio Retina mode. The software(version 2017.100.0.1; OptovueInc)automatically segmented the tissue into four layers, the characteristics of choriocapillaris layer were analyzed. At the same time, the differences between OCTA and ICGA images were compared among CSC patients. The maximum diameters and areas of both choroidal hyperperfusion in ICGA and high flow signal in OCTA were measured. Then, the paired t test was used to analyze the differences between the maximum diameter and area of OCTA and ICGA measurement.

RESULTS: Among 30 cases, high blood flow signals of OCTA were clearly visible in 27 cases, namely the coarse grain region; the inner low flow signals surrounded by high blood flow signals were seen in 21 cases; the outer low flow signals surrounding high blood flow signals were seen in 7 cases. High blood flow signals of OCTA were corresponded with the choroidal hyperperfusion of ICGA images; among these 30 cases, there were low reflection shadows in choroidal hyperperfusion with ICGA for 22 cases, for 21 cases out of these 22 cases, low flow signals inside of high flow signals of OCTA could be seen; 9 out of 30 cases, there were low reflection halo outside of choroidal hyperperfusion of ICGA, and 7 out of these 9 cases, low flow signals outside of high flow signals of OCTA could be seen; still for those 30 cases, leakage point in late ICGA could be seen with 14 cases, however, special flow signals in OCTA could not be seen for them. For ICGA, the maximum diameter of choroidal hyperperfusion was 1.589±0.295mm, whose area was 0.705±0.131mm²; while for OCTA, the maximum diameter of high flow signal was 1.576±0.293mm, whose area was 0.745±0.138mm². By using paired t test, there was no statistical difference between the maximum diameter of choroidal hyperperfusion in ICGA and the maximum diameter of high flow signal in OCTA, nor difference between the area of ICGA and OCTA.

CONCLUSION: The high flow signals can be clearly visible in OCTA, which are corresponded with choroidal hyperperfusion in ICGA.OCTA can substitute ICGA for diagnosis of CSC patients, and guide the treatment of PDT.