Seeing objects as small is a type of perceptual syndrome disorder, in which the optic nerve degenerates and loses its conduction function due to various reasons, resulting in blurred vision or even blindness. Such as looking at the object image is much smaller than the physical object. So, what are the causes of small-sized vision? The following are the causes of small vision. 1, acute hemorrhage caused by hemorrhagic shock: so that the blood pressure is too low, so that the small blood vessels on the optic disk blood supply is insufficient, blood circulation disorders occur, thus infarction, local tissue hypoxia. 2.Vascular diseases such as hypertension, arteriosclerosis, diabetes mellitus, temporal arteritis and so on: make the wall of blood vessel change, blood vessel narrow or occlusion, the small blood vessels on optic disc also change because of it, cause local ischemia. 3.Severe anemia: the oxygen carrying capacity of blood is reduced; the viscosity of blood is increased, such as erythrocytosis, leukemia, etc., because of the slowing down of blood circulation, resulting in the lack of oxygen to the optic disc. 4. Increased intraocular pressure in glaucoma: the small blood vessels in the optic disk are pressurized, which causes poor blood flow and insufficient blood supply. 5, vasculitis: giant cell arteritis, nodular polyarteritis, systemic lupus erythematosus, Buergers disease, allergic vasculitis, post-viral vasculitis, after vaccination and immunization, syphilis, radiation necrosis. 6.Systemic vascular disease: hypertension, atherosclerosis, diabetes mellitus, migraine, aortitis, carotid artery obstructive lesions. 7, hematologic disorders: true erythrocytosis, sickle cell disease, acute hypotension.