There are the following possible causes of blurred vision: 1. The most common cause is refractive error, which is often referred to as myopia, hyperopia or astigmatism, and requires an optometric examination and appropriate glasses. 2. Cataracts, which are more common in the elderly, have symptoms of blurred vision in the early stages of cataracts, and require cataract extraction and IOL implantation if cataracts worsen. 3. The blurred vision can also be caused by inflammatory diseases such as keratitis and iritis. 4, Fundus disease, various causes of fundus disease can appear blurred vision, such as optic nerve atrophy, fundus hemorrhage, macular degeneration, etc. 5, glaucoma, when the eye pressure is increased corneal edema will appear blurred vision.