Choroidal vascular occlusion in internal carotid artery obstruction

Purpose: To determine choroidal vascular abnormalities in eyes with internal carotid artery obstruction (ICO). Methods: We examined eight eyes with ICO with wide-angle indocyanine green (ICG) video-angiography beginning in the posterior fundus. Another angiography was performed in three eyes to observe the arterial phase of the temporal peripheral fundus. ICG angiography was done until the late choroidal venous phase or for more than 10 minutes. Results: Slow dye filling in the choroidal arteries and delayed filling of the posterior watershed zone occurred in all eyes. Delayed perfusion or multiple patchy occlusions of choriocapillaris was seen in all eyes. There were delayed perfusion and/or occlusion in the peripheral watershed zone in the examined three eyes. The super-late-phase angiograms showed hyperfluorescent lines corresponding to choroidal veins. Conclusion: Elongated arm-to-choroid circulation and delayed intrachoroidal circulation times suggest severe choroidal hypoperfusion. Choroidal hypoperfusion resulted in multiple occlusions of the choriocapillaris and attenuated choroidal vessels. Slow filling or nonperfusion of the peripheral watershed zone was another characteristic finding. Linear hyperfluorescence may reflect severely damaged choroidal venous walls. These findings are useful to understand choroidal angiopathy in ICO or high-grade stenosis, and to diagnose ocular ischemic syndrome.