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What causes blurry vision?

Blurry vision can be a frightening experience, particularly if you are used to having clear eyesight that suddenly loses sharpness and becomes hazy. There are many, many different causes of blurred vision; in fact, Healthline.com lists 84 possible reasons and conditions.

Blurry vision can be caused by anything from a migraine, to a stroke, to a number of common eye conditions known as refractive errors.

On rare occasions, blurry vision can also be a sign of a something much more serious. Some of these conditions (such as a detached retina) are medical emergencies as they can cause blindness or even death. It’s very important to see a doctor if you are experiencing blurred vision, especially if your vision has changed suddenly and dramatically and is accompanied by other severe symptoms.

Refractive errors and blurred vision

If your vision has simply been gradually deteriorating over a period of time, making it harder and harder for you to see objects either close up or in the distance (or both), it is more likely that you have an eye condition that can be treated with contact lenses or glasses. In these cases, you may be better off seeing an optometrist.

Refractive errors that can cause blurry vision include: What causes blurry vision

Migraine with aura

Another common cause of sudden blurry vision is a migraine with ‘aura’. An aura is the visual disturbance that occurs before the onset of the headache itself. The aura may take the form of blurry vision, ‘blind spots’ in your vision, halos and zigzag shapes. This type of blurry vision is generally harmless and will abate once the headache starts.


A stroke is a much more serious cause of blurry vision and is considered a medical emergency. A stroke occurs when an artery that supplies blood to the brain is damaged. This prevents a part of the brain getting enough oxygen and cells begin to die.

Because a stroke is a problem with the brain itself, it can manifest various symptoms in different parts of the body. Signs and symptoms of a stroke include:

  • vision that is blurred or blackened, or double vision
  • numbness on one side of the body
  • slurred speech or difficulty speaking
  • general confusion
  • loss of balance and trouble walking
  • dizziness
  • sudden severe headache
  • paralysis.

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