Methods: We conducted a thorough ophthalmic examination and OCTA on 20 BU patients and 26 control subjects. Optic nerve head (ONH) flow and non-flow areas, capillary vessel density (CVD) at the optic disc, superfi cial capillary plexus (SCP) flow and non-flow areas (FAZ), outer retina and choriocapillaris (CC) flow areas, and SCP thickness at the parafoveal region were measured using OCTA.

Results: We found signifi cantly lower ONH flow area (1.57±0.17 vs. 1.68±0.08 mm²) and CVD at the optic disc (OD)-centered 4.5x4.5 mm² area (53.99±4.94 vs. 58.13±1.77%) (p<0.05) but higher ONH non-flow area (0.44±0.23 vs. 0.27±0.10 mm2, p=0.040) in BU patients compared to the controls. There was no signifi cant difference in SCP flow and non-flow areas (FAZ), outer retina and CC fl ow areas and parafoveal SCP thickness between the two groups (p>0.05). There was a negative correlation between BCVA (logMAR) and the ONH flow area (r= -0.363, p=0.049), SCP fl ow area (r= -0.703, p<0.001), parafoveal SCP thickness (r= -0.348, p=0.035) and CVD in the OD-centered area (r= -0.644, p=0.002) in BU patients.

Conclusion: While there were no micro-vascular changes at the parafoveal region. The CC, ONH-related parameters such as decreased ONH flow area and CVD at the optic disc and increased ONH non-flow area were observed regardless of disease duration and visual acuity in BU patients. Keywords : Behçet uveitis, Optic nerve head, Optical coherence tomography angiography