Central retinal artery occlusion has an abrupt onset, mostly in one eye, but may involve the other eye a few days or years later. The absolute majority of patients are over 40 years of age, and there is no significant difference in gender. The diagnosis of central retinal artery occlusion should be made and prevention should be done actively. Diagnostic point 1: In the case of arterial trunk obstruction, the retina at the posterior pole of the fundus is cloudy and the macula is cherry colored. In the later stage, the retinal clouding gradually disappears, but because the inner layer is necrotic and atrophied, vision cannot be restored, the artery becomes thinner like a white line, and the optic papilla is pale. Diagnostic point 2: Fundus fluorescence angiography: fluorescence fills the retinal artery for an extended period of time; if the obstruction is not improved, the angiography shows no dye perfusion in the central artery. In case of branch obstruction, blood flow is seen to be abruptly interrupted at a point of the branch, and this point is the location of the obstruction. Diagnostic point 3: The disease should be differentiated from acute optic neuritis: in the latter, there is sudden loss of visual acuity with congested, poorly defined, mildly elevated optic papillae, which may be surrounded by hemorrhage and exudate. Diagnostic point 4: Sudden loss of vision. In case of main stem obstruction, there is complete loss of vision or even no light perception; in case of branch obstruction, there is visual field defect in the corresponding area. Unless the obstruction is eliminated within a short period of time, the visual impairment is difficult to recover.