The causes of blurred vision include physiological factors (e.g. staying up late, prolonged eye use, etc.) and pathological factors (e.g. refractive error, cataract, etc.). 1. Physiological factors: after staying up late and using eyes for a long time, it will lead to eye fatigue and blurred vision easily, which is a physiological phenomenon, and vision can be improved after resting for a period of time. 2. Pathologic factors: (1) Refractive error: refractive error refers to the state of relaxation, parallel light through the refractive system of the eye can not form a clear image on the retina, mainly including myopia, hyperopia and astigmatism, can appear in the phenomenon of blurred vision. It can be improved by wearing glasses or surgical treatment. (2) Cataract: Cataract refers to the clouding of the lens caused by various reasons. The main manifestations include vision loss, visual field defects, refractive changes, etc., which can lead to blurred vision. Surgery is usually required. (3) Glaucoma: Glaucoma is mainly characterized by characteristic optic nerve atrophy and visual field defects, which mainly manifests as eye pain, eye distension, reduced visual acuity, etc. Blurred vision may also occur. Treatment should be chosen according to different types of glaucoma, such as acute closed-angle glaucoma can be treated with laser excision or other anti-glaucoma surgery after lowering intraocular pressure and controlling inflammation. (4) Other diseases: Optic neuritis, retinal vein occlusion and other diseases that can damage the optic nerve can cause blurred vision in patients. It is suggested that patients should consult a doctor in time after excluding physiological factors, to clarify the cause of the disease and follow the doctor’s instructions.