Materials and Methods: Twenty-one consecutive subjects (14 male and 7 female) with an age range of 51-85 years who had ICA stenosis (with ?40% ICA stenosis on one side and less than 40% stenosis on the other side ) were included in our study. 21 eyes with ?40% ipsilateral ICA stenosis as the patient group and 21 eyes with less than 40% ipsilateral ICA stenosis as the control group of 21 subjects were included in the study. Choroidal thicknesses (CT) were measured at eleven locations: the fovea, 500-1500-3000?m temporal to the fovea, 500-1500-3000?m nasal to the fovea, 1000-2000?m superior to the fovea, and 1000-2000?m inferior to the fovea by enhanced depth imaging optical coherence tomography (EDI-OCT). The correlation between CT values and ipsilateral ICA stenosis ratios was explored.

Results: Except at 3000?m temporal and 1000?m inferior, all CT measurements at other nine localizations were signifi cantly decreased in the patient group as compared to the control group (p<0.05 ). There was no a proportional relationship between the CT values and ipsilateral ICA stenosis ratios.

Conclusion: Choroidal thickness is decreased on the same side with >40% carotid artery stenosis as compared to the fellow eyes with <40% stenosis. It is important to diagnose and treat ICA stenosis before permanent complications occur. Therefore, we suggest investigating patients with CT reduction for early detection of ICA stenosis. Keywords : Carotid artery stenosis, Choroidal thickness, EDI-OCT, 3D Carotid artery angiography