Evaluation of central retinal and choroidal thicknesses, macular vascular density and foveal vascular zone changes by optical coherence tomography and optical coherence angiography in behçet's patients

Purpose: It was aimed to evaluate the macular vascular density and avascular zone changes with optical coherence tomography angiography in Behcet patients and to compare these findings in patients with and without ocular involvement and healthy control group. Material and Method: The study included Behcet patients with ocular involvement followed up by the uvea unit of Akdeniz University Faculty of Medicine, and Behçet patients without ocular involvement who were consulted by the dermatology and rheumatology units for control without a previous history of uveitis. The group with ocular involvement was divided into patients with anterior uveitis and posterior uveitis. The visual acuity of the patients, the drugs used and the duration of the disease were recorded. Optical coherence tomography (OCT) findings of retinal, ganglion cell layer, RNFL and choroidal thickness, presence of epiretinal membrane, presence of cystoid macular edema, presence of pigment epithelial detachment, presence of foveal atrophy were recorded. In the optical coherence tomography angiography (OCTA) findings, the foveal avascular zone (FAZ) area, vascular density in the superficial and deep capillary network, and FAZ irregularities were recorded. At the same time, fundus fluorescein angiography (FFA) was also taken in the group with ocular involvement, and FAZ findings were compared with OCTA. Results: A total of 186 eyes of 96 patients, 50 male (52.1%) and 46 (47.9%) female, were included in the study. The mean age of the groups was 33.6, 39.2, 38.5 respectively. While the mean duration of Behçet's disease was 7.71 years in the first group, it was 8.89 years in the second group. In OCT findings, no statistically significant difference was found between the groups in central retinal thickness, central choroidal thickness and ganglion cell layer thickness. The mean retinal nerve fiber layer thickness was 14.5, 9, 9,7 µm respectively and found to be statistically significantly higher in the first group (p=0.019). Perifoveal capillary network irregularities were found to be significantly higher in the group of Behçet's patients with ocular involvement in OCTA findings than in the group without ocular involvement in both capillary plexuses (p<0.01). The rate of FAZ irregularity in the second group was found to be significantly higher than the control group (p<0.05). The superficial capillary plexus FAZ area in the first group was found to be significantly larger than the second group and control group (p<0.05). Superficial capillary plexus FAZ area measurement did not differ significantly between the second group and the control group. In the first group, superficial capillary plexus parafoveal inferior and superior vascular density were found to be significantly lower than the second group and control group (p<0.05). The total vascular density of the superficial capillary plexus was found to be significantly lower in the first and second groups compared to the control group (p<0.05). Although deep capillary plexus FAZ area measurements were found to be larger in the first group, no statistically significant difference was found between the groups (p=0.327). In deep capillary plexus vascular density measurements, parafoveal inferior vascular density was found to be significantly lower in the first group (p=0.009). Choriocapillaris total vascular density values in the first group were found to be significantly lower than in the second group and control group (p<0.05). There was no statistically significant difference in OCT, OCTA and FFA findings in anterior and posterior uveitis groups. The mean FAZ area in FFA findings was calculated as 0.93 mm2. FAZ irregularity was observed in 30 eyes, peripheral vasculitis in 34 eyes, macular edema in 11 eyes and active or sequela optic nerve involvement in 21 eyes. Conclusion: Optical coherence tomography angiography (OCTA), a new technology, is an important non-invasive imaging method for detecting macular microvascular changes in Behcet uveitis. Microvascular changes were detected in the macula in Behcet patients with ocular involvement compared to the control group. In Behcet patients without ocular involvement, some microvascular changes were detected when compared to the control group, although not as much as in the group with ocular involvement. In this respect, we predict that OCTA will play an important role in the diagnosis and follow-up in Behcet's disease with ocular involvement, and in predicting the progression of the disease in patients without ocular involvement. Keywords: Behçet disease, optical coherence tomography angiography, uveitis, foveal avascular zone, vascular density