Choroidal vascularity index and submacular choroidal thickness are decreased in patients with active and inactive ocular Behçet disease assessed with enhanced-depth imaging optical coherence tomography

To investigate changes in the choroid using the choroidal vascularity index (CVI) and choroidal thickness (ChT) in patients with ocular (OBD) and non-ocular Behçet disease (non-ocular BD).Sixty-eight OBD patients, 40 non-ocular BD patients, and 40 healthy control subjects were included. ChT was measured using optical coherence tomography (OCT) in enhanced-depth imaging (EDI) mode (EDI-OCT; sub-foveal ChT at 1000 μm, nasal ChT at 1000 μm temporal ChT). The CVI value (%) was calculated by dividing the luminal area by the sub-foveal total choroidal area.The mean sub-foveal ChT (297 ± 68 µm), nasal ChT (261 ± 66 µm), and temporal ChT (272 ± 68 µm) in eyes with OBD and the mean sub-foveal ChT (286 ± 31 µm), nasal ChT (266 ± 29 µm), and temporal ChT (269 ± 32 µm) in eyes with non-ocular BD were significantly decreased compared with those regions in healthy control subjects (333 ± 69, 301 ± 75, and 312 ± 70 µm, respectively). Additional subgroup analysis was performed for active OBD, inactive OBD, non-ocular BD, and the control group, and in pairwise comparisons, the CVI value was significantly decreased in both active (64.3 ± 3.1) and inactive OBD groups (64.2 ± 4.5) compared with healthy control subjects (67.2 ± 3.6; p = 0.026 and p < 0.001, respectively). There was no significant difference between non-ocular BD (65.9 ± 3.4) and control subjects (67.2 ± 3.6) for CVI measurements (p > 0.05).Decreased CVI values in OBD suggest that uveitis affects the choroidal vasculature and that perfusion is affected by uveitis, whereas systemic inflammation in non-ocular BD does not affect them. In addition, the choroid in uveitis is affected by the chronicity of the disease rather than disease activity. ChT measurements and CVI values may be a novel and robust prognosticating biomarker to evaluate choroidal vasculature and to monitor disease progression in OBD patients because EDI-OCT is a non-invasive imaging modality. However, CVI does not seem to be a biomarker for monitoring of disease activity or treatment efficacy.