Branch retinal artery occlusion is a type of retinal artery occlusion that usually manifests as a dramatic loss of vision. Causes of this disease include atherosclerosis, spasm of the central retinal artery, and peripapillary inflammation of the central retinal artery. Compressive disorders include glaucoma, orbital trauma, and retrobulbar tumors, diseases with abnormal coagulation mechanisms, and embolus embolism. Symptoms manifest themselves in different degrees of vision loss, a fixed dark shadow is visible in a certain area of the visual field, and in the fundus examination, it can be found that the diameter of the obstructing artery is thinned, and the gray-white edema of the retina in the area supplied by the affected artery is the most obvious. Early treatment is needed for this disease, otherwise it is easy to cause optic nerve atrophy, and the treatment measures mainly include lowering the intraocular pressure, inhalation of a mixture of oxygen and carbon dioxide, retrobulbar injection and systemic application of vasodilators.