Sudden blurring of vision generally results from a disorder affecting the retina or nerve pathways between the brain and the eye, clouding of usually transparent eye structures or refractive errors, according to Merck Manuals. Blurred vision can occur in one or both eyes and may be accompanied by other symptoms.
Common causes of blurred vision in only one eye accompanied by pain include trauma and corneal problems, such as infection, extreme dryness and contact lens issues, notes Patient.co.uk. Blurred vision accompanied by pain and occurs in both eyes could be caused by malignant hypertension. Sudden blurred vision in a person with a compromised immune system could result from an infection of the retina, such as is caused by Toxoplasma parasites, explains Merck Manuals. Optic neuritis, in which the optic nerve is inflamed, is another possible cause.
Sudden blurred vision which is not accompanied by pain and is isolated to just one eye could be caused by a variety of conditions, including central retinal vein occlusion, intermediate or posterior uveitis, and toxic illness, reports Patient.co.uk. Vision that blurs suddenly in both eyes, without any reported accompanying pain, could result from cerebrovascular disease, poorly controlled diabetes mellitus or certain drugs, such as steroids and anticholinergics.
Eye strain is one of the most common blurred vision causes, resulting from long hours spent staring at a computer screen, reading, watching TV and performing similar activities in a poorly lit environment, as Health Hype explains. Other symptoms may include tiredness in the eyes and eyelids, watery eyes, and a dull ache. Stroke, brain tumors and traumatic injuries to the brain can also cause blurred vision because they interrupt the light signals carried from the retina to the brain through the optic nerve. Blurred vision occurs suddenly in trauma patients, while tumor patients experience a more gradual development. Anyone who experiences sudden blurred vision should consult a doctor immediately for diagnosis and treatment.