Seen Differently

All patterns

Double vision

Everything arrives twice, slightly out of step, and your brain can't decide which copy is real.

Typical visionWith double vision
Moderate: two overlapping copies of the scene drift apart.

Type

Try it

Which bus is pulling in, and is it safe to cross yet?

What's happening

Double vision (diplopia) happens when the two eyes stop pointing at exactly the same spot, or when something inside one eye splits the light. The brain receives two images it can't fuse. It can come and go, get worse when you're tired, or appear suddenly.

This simulation is for understanding and empathy. It is not a diagnosis and doesn't replace an eye examination.

What you might notice

A ghost beside everything

A second copy, fainter or just as sharp, sits next to whatever you look at.

Worse in one direction

Looking left, right, up or down can pull the images further apart.

Gone with one eye shut

Covering one eye often makes it disappear. That's a useful clue for your doctor.

Tiring

Forcing the images together is exhausting, especially late in the day.

Where it gets hard

  • Pouring a drink or grabbing a handrail, because depth becomes unreliable.
  • Stairs and kerbs, where two edges appear where there is one.
  • Driving, especially judging oncoming traffic.
  • Reading, as lines of text slide over each other.

Often caused by

Conditions commonly linked to this pattern.

  • Strabismus (misaligned eyes)
  • Palsy of the third, fourth or sixth cranial nerve
  • Thyroid eye disease
  • Myasthenia gravis
  • Nerve damage from diabetes
  • Stroke, head injury or tumour
  • Cataract, keratoconus or dry eye (double image in one eye only)

Treatment and support

Treatment follows the cause. Prism lenses can pull two images back together, patching or eye-muscle surgery helps some types, and botulinum toxin injections can relax an overacting muscle. Treating the underlying illness, such as thyroid disease or myasthenia gravis, often improves the double vision itself.

Looking for research you could join? Search ClinicalTrials.gov or the EU Clinical Trials register.

Get checked the same day if

Double vision comes on suddenly, especially with a headache, a drooping eyelid, weakness, numbness or slurred speech. These can be signs of a stroke or an aneurysm.

If it's sudden or comes with other symptoms, go to an emergency department.

Where to learn more