Eye Conditions

Double vision (diplopia)

Double vision — seeing two images of a single object — can have many causes, from a simple focusing issue to something that needs prompt attention. Whether it's in one eye or both, and how suddenly it came on, are important clues, so it's worth getting checked.

What it is

Double vision comes in two broad types. 'Monocular' double vision is still there when you cover the other eye — usually an eye-surface or lens issue like dry eye, astigmatism or a cataract. 'Binocular' double vision disappears when either eye is covered — it comes from the two eyes not working together, which can be more significant.

Because the causes range from harmless to urgent, working out the type is the first step in sorting it out.

What you might notice

Seeing two overlapping or side-by-side images
Images that separate when you look in a certain direction
Double vision that stays with one eye covered (monocular)
Double vision that clears when either eye is covered (binocular)
Sometimes with headache, a droopy eyelid or eye pain

Recognise these? Book a consultation and we'll help you get to the bottom of it.

When to seek help urgently

Sudden double vision — especially with a headache, a droopy eyelid, weakness, numbness or difficulty speaking — needs urgent medical attention. Call 111 if you have stroke-like symptoms.

What causes it

Monocular double vision often comes from dry eye, astigmatism or a cataract.

Binocular double vision can come from the eye muscles or the nerves that control them, and occasionally points to a condition that needs prompt treatment — which is why new binocular double vision should be assessed.

How we help

Dr Leong will work out which type of double vision you have and what's causing it, using a careful examination to guide the right next step.

Some causes are simple to correct; others need prompt attention — either way, an assessment is the fastest route to an answer.

Explore General Ophthalmology

Common questions

Is double vision serious?

It can be, so it's worth checking — especially if it's new, came on suddenly, or affects both eyes. Some causes are simple to fix; others need prompt attention, which is why an assessment matters.

Why do I see double in only one eye?

Double vision that stays when the other eye is covered (monocular) usually comes from the eye's surface or lens — dry eye, astigmatism or a cataract — rather than something more serious. It's still worth having checked.

What should I do if double vision comes on suddenly?

Sudden double vision, especially with a headache, droopy eyelid, weakness or slurred speech, needs urgent care — call 111. Otherwise, contact us promptly for an assessment.

Can glasses fix double vision?

Sometimes — if it's from astigmatism or the eyes being slightly misaligned, glasses (occasionally with a special prism) can help. The right fix depends on the cause, which is why it's worth pinning down first.

This page is general information, not medical advice, and doesn't replace a consultation. For anything specific to your own eyes, call us for advice or to book an appointment with Dr Leong on 04 470 7663.

Ready to see clearly?

Book a consultation with Dr Leong, or call the clinic to talk it through. We're here to help you see your very best.

Book a Consultation 04 470 7663