ObjectiveIdentifying collaterals from external carotid artery (ECA) is necessary before treatment of ophthalmic artery (OphA) aneurysm. We present a manual carotid compression test to verify collaterals in ophthalmic artery aneurysms, and evaluate its usefulness.Materials and MethodsFrom March 2013 to December 2017, endovascular coiling was performed 19 consecutive patients with 20 OphA aneurysms. We performed manual carotid compression test for patients who had aneurysms incorporating entry of OphA. Clinical and angiographic outcomes were investigated.ResultsOf 13 cases underwent manual carotid compression test, 12 cases were confirmed collateral flow from ECA to OphA. During the coil embolization, we tried to maintain the original OphA flow even if it has a collateral anastomosis. Among them, OphA occlusion occurred in one patient during coiling. Recurrence of aneurysm was occurred in a ruptured case and additional embolization was required.ConclusionsThe manual carotid compression test is useful method to identify the collaterals from ECA in patients with OphA aneurysm. This test can be used as a screening test for confirming collateral flow in OphA aneurysms or as an alternative for patients who are difficult to perform BTO.