Abstract AIM: This study aimed tomeasureinactive giant cell arteritis (GCA) using optical coherence tomography angiography (OCT-A) in patients previously affected by GCAand treated (patient group), and to compare these measures with those of healthy volunteers (control group). METHODS: In this observational case-control study, 18 eyes of 18 GCA cases previously diagnosed, treated with anterior arteritic ischemic optic neuropathy (AAION) were examined. 22 eyes of 22 ophthalmically healthy volunteers were included in the study. After external ophthalmic examinations of all participants were performed, their measurements were made with serial OCT-A. Superficial capillary plexus (SCP), deep capillary plexus (DCP), foveal avascular zone (FAZ), area covering 300 degrees around the fovea (FD-300), choriocapillaris (CC), retinal nerve fiber layer (RNFL), cup/disc (C/D) ratio and optic disc vessel densities (OD-VD) were evaluated. A value of p<0.05 was considered significant for statistical analyses. RESULTS: There was no difference between the two groups in terms of age, gender and shooting quality. Whole-SCP, SCP-foveal, SCP-parafoveal and SCP-perifoveal VD values were lower in the patient group. Whole-DCP, DCP-parafoveal and DCP-perifoveal VD values were also lower in the patient group than control group. FAZ areas were similar between groups, but the FD-300 VD was different. Whole-OD VD and inside-OD VD were significantly lower in the patient group. Peripapillary-OD VD and RNFL values were similar. The C/D ratio was higher in the patient group.The effect on the microvascular process was significant in OCT-A. CONCLUSION: The results suggested that even if the ischemic process still continues and there is no active inflammation, microvascular structures may continue to be affected.