Parafoveal Microvascular Alterations in Ocular and Non-Ocular Behҫet's Disease Evaluated With Optical Coherence Tomography Angiography

Abstract

Purpose: To compare quantitative optical coherence tomography angiography (OCT-A) measurements of the parafoveal microvasculature in retinal capillary plexuses among Behҫet uveitis (BU) patients, non-ocular Behҫet's disease (NOBD) patients, and healthy volunteers (HVs).

Methods: Sixty-eight subjects were enrolled in this prospective observational cross-sectional study. OCT-A imaging was performed using the Heidelberg Engineering Spectralis OCT. A custom algorithm was developed to calculate the vessel density (VD) in three retinal vascular layers: deep capillary plexus, intermediate capillary plexus, and superficial vascular plexus. The foveal avascular zone (FAZ) and acircularity index were calculated for the whole retinal vascular complex.

Results: We analyzed one eye from 21 BU patients (age, 51 ± 10 years), 23 NOBD patients (age, 48 ± 14 years), and 22 HVs (age, 44 ± 13 years). One-way multivariate analysis of covariance showed a statistically significant difference in VD among the three groups when combining the layers after controlling for scan quality (P < 0.001). The VD was lowest in the BU group and highest in the HV group in all layers. The FAZ area was also statistically significant different among the groups (P < 0.005), with the largest FAZ areas in BU patients and smallest FAZ areas in the HV group. However, no statistically significant difference was found for the acircularity index.

Conclusions: The parafoveal microvasculature is affected not only in BU patients but also in NOBD patients. Most deviations in the retinal microcirculation in Behҫet patients were found in the deeper layers of the retina by using the quantitative VD measurement.

Figure 1.

OCT-A en face images of two BU patients (top), two NOBD patients (middle), and two HVs (bottom). The subjects’ ages, from top to bottom, were 53 years and 35 years (BU); 54 years and 32 years (NOBD); and 54 years and 37 years (HVs). Shown from left to right are the DCP, ICP, SVP, and those retinal vascular layers together (whole retinal vascular complex). The corresponding metrics are presented in the images; the VD (%) was calculated in the DCP, ICP, and SVP, and the FAZ area (mm²) and acircularity index (AI) were calculated in the whole retinal vascular complex.

Figure 2.

The distribution of VD (%) in the three groups (BU, NOBD, and HV) in the DCP, ICP, and SVP. The dotted lines represent the median and quartiles.

Figure 3.

The violin plot on the left shows the distribution of the FAZ area (mm²) of the three groups (BU, NOBD, and HV) in all of the vascular layers combined. The violin plot on the right shows the distribution of the acircularity index of the FAZ for each group. The dotted lines represent the median and quartiles.