Abstract: Ocular ischemic syndrome (OIS) will not occur in individuals who develop well the laterals between internal-internal and internal-external carotids. However its early-stage cases might be misdiagnosed or missed diagnosed. The core of OIS is chronic progressive hypo-perfusion of ophthalmic artery. Ischemic eye pain, amaurosis fugax, light-induced amaurosis is significant symptoms in early stage of OIS. Spontaneous or light digital palpation induced retinal artery pulsation is characteristics. Mid-periphery retina sees intraretinal hemorrhages, wild-spread microaneurysms. Angiography shows delayed choroid and retinal circulation. This article begins with analysis of traditional definition of OIS, moves to its pathogenesis, early symptoms, fundus manifestations, and concludes with recent knowing of treatments, so as to improve the recognition of oculist on OIS, trying to avoid or reduce the occurrence of neovascular glaucoma. (Ophthalmol CHN, 2024, 33: 249-256)

Key words: ocular ischemic syndrome, ischemic eye pain, light-induced amaurosis, retinal artery pulsation