Evaluation of retinal and choroidal microcirculation in Behçet’s disease

Purpose: To investigate retinal perfusion by optical coherence tomography (OCT)-angiography and choroidal vascular features using an OCT-based image binarization method in patients with Behçet’s disease (BD) without clinical ocular involvement. Methods: This study included 38 patients with non-ocular BD and 35 healthy participants. Macular region was evaluated with OCT-angiography (Optovue, Inc., Fremont, CA). A 6.0 × 6.0 mm rectanglescan centred on the fovea was used to record the scans. The enhanced depth imaging OCT scans (Heidelberg Eye Explorer version 1.8.6.0; Heidelberg Engineering) of the macula and peripapillary scans of the optic nerve head were binarized using ImageJ software (National Institutes of Health, Bethesda, MD, USA). The luminal area (LA), stromal area (SA), total choroidal area (TCA), and choroidal thickness (CT) were analysed. The choroidal vascularity index (CVI) was calculated as the ratio of the LA to the TCA. Results: Vessel density values of the superficial and deep macular capillary plexus were similar between the two groups (all p> 0.05). There was no significant difference between the groups in terms of the CT and TCA values in the macula and in all peripapillary sectors (all p> 0.05). However, the macula and temporal, nasal, and inferior sectors of the peripapillary area had significantly lower CVI values in the BD group compared with controls (p= 0.009, p= 0.002, p= 0.010, and p= 0.008, respectively). Conclusions: Retinal microperfusion deficit was not observed in non-ocular Behçet patients. CVI may be a more robust marker than CT to indicate choroidal perfusion. A reduced CVI may suggest subclinical ocular involvement and choroidal ischemia in these patients.