Evaluation of retinal, choroidal and peripapillary vascular flow in patients with Thyroid Associated Ophthalmopathy (TAO) using Optical Coherence Tomography Angiography (OCT-A)

Purpose: The aim of this study was to evaluate changes in choroidal thickness and in choroidal vascular blood flow in patients with TAO and their relationship with clinical features and disease activity using SD-OCT and Angio-OCT technology. Methods: Eighteen patients and control subjects underwent a complete eye examination, OCT and angio - OCT. We also obtained angiographic scans at 3 different consecutive levels (L1, L2 and L3) below the choriocapillary. Results: The subfoveal choroid was significantly thicker in TAO patients than the control eyes (285.6275 ± 32.5 μm compared to 135.89 ± 19.8 μm, respectively, p = 0.0089). The correlation analysis in the TAO group showed a significant correlation between the choroidal thickness and EUGOGO clinical score (r = 0.84, p = 8.44032E - 07). Vascular flow of choriocapillary was markedly reduced in subjects with TAO compared to healthy subjects (49.78 ± 4.5 vs. 53.36 ± 1.07; p = 2.5105E - 07) and vascular flow of the deeper layer L3 resulted higher in subjects with TAO than in healthy subjects (46.9 ± 20.23 and 41.475 ± 3.06; p = 0.01168). Conclusions: Subfoveal choroidal thickness and choroidal blood flow were significantly different in patients with TAO compared to healthy subjects.