A patch of blurred vision in the eye may be associated with corneal opacities, cataracts, uveitis, and flaky vitreous clouding. 1. Corneal opacities: If keratitis occurs or if there is a history of corneal ulcers, the inflammation causes wounds in the cornea, and although the wounds have healed, they may still leave scars, which can lead to blurred vision. 2. Cataract: In cataract patients, the lens is unevenly clouded, but patchy and cloudy. When light passes through the patch, it does not form an image efficiently, leading to the symptom of seeing a piece of blur. 3. Uveitis: if there is trauma, autoimmune deficiency, infection, etc., it is easy to develop uveitis. When uveitis attacks, it will lead to sudden blurring of vision, photophobia, mixed congestion of the eyeballs, tearing and other symptoms. 4. Pieces of vitreous clouding: If there is a large piece of clouding in the vitreous, it will cause opacity of refractive medium, leading to blurring of vision, and the blurring is movable. The eyes appear to see a piece of blur, should go to the hospital in time, clear cause of the disease, follow the doctor’s instructions for targeted treatment.