Blurred vision is an ocular symptom where vision becomes less precise and there is added difficulty to resolve fine details. Temporary blurred vision may involve dry eyes, eye infections, alcohol poisoning, hypoglycemia, or low blood pressure. Other medical conditions may include refractive errors such as myopia, high hypermetropia, and astigmatism, amblyopia, presbyopia, pseudomyopia, diabetes, cataract, pernicious anemia, vitamin B12 deficiency, thiamine deficiency, glaucoma, retinopathy, hypervitaminosis A, migraine, sjögren's syndrome, floater, macular degeneration, and can be a sign of stroke or brain tumor. Causes There are many causes of blurred vision: Refractive errors: Uncorrected refractive errors like myopia, high hypermetropia, and astigmatism will cause distance vision blurring. It is one of the leading cause of visual impairment worldwide. Unless there is no associated amblyopia, visual blur due to refractive errors can be corrected to normal using corrective lenses or refractive surgeries. Presbyopia due to physiological insufficiency of accommodation (accommodation tends to decrease with age) is the main cause of defective near vision in the elderly. Other causes of defective near vision include accommodative insufficiency, paralysis of accommodation etc. Pseudomyopia due to accommodation anomalies like accommodative excess, accommodative spasm etc. cause distance vision blurring. Alcohol intoxication can cause blurred vision. Use of cycloplegic drugs like atropine or other anticholinergics cause visual blur due to paralysis of accommodation. Cataracts: Cloudiness over the eye's lens, cause blurring of vision, halos around lights, and sensitivity to glare. It is also the main cause of blindness worldwide. Glaucoma: Increased intraocular pressure (pressure in the eye) cause progressive optic neuropathy that leads to optic nerve damage, visual field defects and blindness. Sometimes glaucoma may occur without increased intraocular pressure also. Some glaucomas (e.g. open angle glaucoma) cause gradual loss of vision and some others (e.g. angle closure glaucoma) cause sudden loss of vision. It is one of the leading cause of blindness worldwide. Diabetes: Poorly controlled blood sugar can lead to temporary swelling of the lens of the eye, resulting in blurred vision. While it resolves if blood sugar control is reestablished, it is believed repeated occurrences promote the formation of cataracts (which are not temporary). Retinopathy: If left untreated, any type of retinopathy (including diabetic retinopathy, hypertensive retinopathy, sickle cell retinopathy, anemic retinopathy, etc.) can damage retina and lead to visual field defects and blindness. Hypervitaminosis A: Excess consumption of vitamin A can cause blurred vision. Macular degeneration: Macular degeneration cause loss of central vision, blurred