Merck Manual

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Quick Facts

Sudden Vision Loss

By

The Manual's Editorial Staff

Last full review/revision Sep 2019| Content last modified Sep 2019
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NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
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What is sudden vision loss?

Sudden vision loss is when you lose some or all of your vision quickly. The loss can happen within a few minutes or over a few days. Vision loss differs from blurry vision. Blurry vision is when you don't see as clearly as you once did.

  • The vision loss may be in one or both eyes

  • The vision loss may affect the whole eye or just part of the eye

  • You may also have eye pain, depending on what's causing your sudden vision loss

Sudden vision loss is an emergency—go to the hospital right away.

What causes sudden vision loss?

Most common causes:

  • A blocked blood vessel in your eye

  • An eye injury

  • Bleeding inside your eye—people with diabetes are at risk for this

Less common causes:

  • Stroke or mini-stroke (when the flow of blood to an area of your brain is cut off)

  • Glaucoma (high pressure inside your eye)

  • Retinal detachment (when your retina, the thin, light-sensing layer at the back of your eye, pulls away from the eyeball)

Some problems cause total vision loss. The same problems may cause only partial vision loss if they affect only part of your eye.

When should I see a doctor?

Go to the hospital right away if you have sudden vision loss. Most of the time, the cause is serious.

Even if your vision returns quickly on its own, sudden vision loss can be a sign that you may have had a mini-stroke.

What will happen at my doctor visit?

Doctors will ask about your symptoms and health history.

Doctors will:

  • Check your vision with an eye chart

  • Check how your eyes react to light

  • See whether your eyes can follow a moving object

  • Put some liquid drops in your eye (you may have a burning feeling that lasts a few seconds)

  • Look into your eye using a special magnifying light (the light is very bright)

  • Measure the pressure in your eye (there are many ways to do this, but none of them hurt)

  • Check whether you can see colors

They may also check other parts of your body, such as your skin or nervous system.

What tests will I need?

Doctors will do tests as needed, depending on what they think is causing your vision loss:

  • Ultrasound (uses sound waves to take a picture of the inside of your eye, particularly your retina)

  • MRI of your head to check the nerve from your eye and to see whether you had a stroke

  • Blood tests

How do doctors treat sudden vision loss?

Doctors will treat the problem that's causing your vision loss.

In some cases, treatment won't bring back your vision, but getting treatment quickly can help protect the vision in your other eye.

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
Click here for the Professional Version
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