Double Vision (Diplopia)

Double vision, or diplopia, can appear as a shadow-like second image or as two fully separate images. It can interfere with reading, walking, depth perception, and driving. The first useful question is simple: does it go away when either eye is covered?

What Double Vision Feels Like

People describe double vision in different ways, and those details help identify the cause:

• Seeing two separate images side-by-side (horizontal diplopia)
• Seeing one image above the other (vertical diplopia)
• Images appearing tilted or at an angle to each other
• Ghost images or shadows around objects
• Difficulty reading because letters seem to overlap
• Trouble judging distances or depth
• Closing one eye to see clearly
• Tilting or turning your head to reduce the double image
• Worsening symptoms when tired or at the end of the day
• Double vision that comes and goes throughout the day
• Feeling dizzy or off-balance because of the visual confusion
• Difficulty driving, especially at night
• Eye strain or headache from trying to focus

Common Causes

Binocular Double Vision (Goes Away When One Eye Is Covered)

Binocular diplopia occurs when the two eyes are not properly aligned. Causes include:

Eye muscle or nerve problems:

• Sixth cranial nerve palsy (abducens nerve)-difficulty looking outward
• Fourth cranial nerve palsy (trochlear nerve)-vertical misalignment, often with head tilt
• Third cranial nerve palsy (oculomotor nerve)-may include droopy eyelid and dilated pupil
• Myasthenia gravis-muscle weakness that worsens with use
• Thyroid eye disease-swelling of eye muscles from Graves' disease

Other causes:

• Stroke or brain injury affecting eye movement centers
• Diabetes or high blood pressure affecting small blood vessels to eye nerves
• Head trauma or concussion
• Multiple sclerosis
• Brain tumors or aneurysms (rare but serious)

Monocular Double Vision (Persists With One Eye Covered)

Monocular diplopia is usually caused by a problem within the eye itself:

• Uncorrected astigmatism or need for new glasses
• Cataracts causing light scatter
• Dry eye creating an irregular tear film
• Corneal irregularities or scarring
• Problems with the lens inside the eye

When to Go to the ER or Urgent Care

What You'll Be Asked in Clinic

Expect very specific questions. They may feel repetitive, but each one helps localize the problem:

About the symptoms:

• When did the double vision start-suddenly or gradually?
• Is it constant or does it come and go?
• Does it affect one eye or both? (They'll have you cover each eye to check)
• Are the images side-by-side, one above the other, or tilted?
• Is it worse in certain directions of gaze?
• Does it worsen as the day goes on or with fatigue?

About your health:

• Do you have diabetes, high blood pressure, or thyroid disease?
• Have you had any recent head injuries?
• Do you have weakness elsewhere (arms, legs, chewing, swallowing)?
• Any recent infections or illnesses?
• What medications are you taking?
• Family history of neurological conditions?

How Double Vision Is Diagnosed

Eye Examination

• Visual acuity testing-reading the eye chart with each eye
• Cover/uncover test-checking eye alignment
• Eye movement assessment-following a target in all directions
• Pupil examination-checking for size differences and reactions
• Slit-lamp exam-examining the front of the eye
• Dilated fundus exam-viewing the optic nerve and retina

Additional Tests

Depending on findings, you may need:

• Optical coherence tomography (OCT)-detailed scan of the retina and optic nerve
• Visual field testing-mapping your peripheral vision
• MRI of the brain and orbits-imaging to look for tumors, aneurysms, stroke, or inflammation
• Blood tests-checking for diabetes, thyroid dysfunction, myasthenia gravis antibodies, or inflammatory markers
• Ice pack test-a simple bedside test for myasthenia gravis (cold improves muscle function)

Treatment Options

Treatment depends entirely on why the images are separating:

Immediate/Temporary Relief

• Patching one eye-can suppress binocular double vision while workup continues
• Fresnel prisms-temporary stick-on prisms for glasses to align images
• Head positioning-turning or tilting the head to minimize diplopia

Treating the Underlying Cause

• New glasses prescription-for monocular diplopia from refractive error
• Prism glasses-permanent prisms ground into lenses for stable misalignment
• Treatment of dry eye-artificial tears, punctal plugs, or other therapies
• Cataract surgery-if cataracts are causing the problem
• Blood sugar and blood pressure control-for microvascular cranial nerve palsies
• Steroids or other immune therapies-for inflammatory conditions
• Medications for myasthenia gravis-pyridostigmine and immunosuppressants
• Thyroid disease management-medication, radiation, or surgery for Graves' disease
• Strabismus surgery-eye muscle surgery to realign the eyes
• Botulinum toxin injections-sometimes used to weaken an overacting muscle

For Serious Causes

• Emergency treatment for stroke
• Neurosurgical intervention for aneurysms or tumors
• Ongoing neurological care for conditions like multiple sclerosis

Patient Guide: Living with Double Vision

For more detail about diagnosis, daily adaptations, prisms, patching, and recovery timelines, see Navigating Double Vision.

What to Expect Going Forward

Many causes of double vision improve or resolve:

• Microvascular cranial nerve palsies (from diabetes or high blood pressure) often improve on their own over 2-3 months
• Post-concussion diplopia typically improves with time and may benefit from vision therapy
• Myasthenia gravis can usually be well-controlled with medication
• Thyroid eye disease often stabilizes and may be treated surgically once stable

Your neuro-ophthalmologist will monitor your progress and adjust treatment as needed. Follow-up appointments are important to track improvement and catch any changes.

Frequently Asked Questions

Is double vision always serious?

Not always. A new glasses prescription, dry eye, cataract, or fatigue-related eye alignment problem can cause it. But sudden double vision, especially with other symptoms, should be evaluated promptly.

Can stress cause double vision?

Stress and fatigue can worsen existing eye alignment problems or cause intermittent double vision in susceptible individuals. If you notice double vision during stressful periods, it's still worth having an evaluation to rule out underlying causes.

Will my double vision go away on its own?

It depends on the cause. Some types, like those from small blood vessel problems in diabetes, often improve within weeks to months. Others may need treatment. Only a proper evaluation can determine your likely course.

Can I still drive with double vision?

Driving with active double vision is unsafe and may violate licensing rules. Avoid driving until the diplopia is resolved, adequately corrected, or your clinician has cleared you to drive. Discuss driving restrictions with your doctor.

Why does my double vision get worse at night?

Dim lighting makes the pupils dilate, which can unmask or worsen certain types of double vision. Additionally, eye muscle fatigue accumulates throughout the day, making symptoms worse by evening.

Is double vision a sign of a stroke?

It can be. Double vision that starts suddenly, especially with facial drooping, arm weakness, speech difficulty, balance trouble, confusion, or severe headache, could indicate a stroke. Call 911 immediately.

How long will the workup take?

An initial neuro-ophthalmology evaluation typically takes 1-2 hours. If imaging or blood work is needed, results may take additional days. Your doctor will explain the timeline based on your specific situation.

Can children get double vision?

Yes. In children, double vision may indicate strabismus (eye misalignment) or other conditions. Unlike adults, children may suppress one image rather than report double vision, so eye alignment problems can sometimes be missed. Regular pediatric eye exams are important.

References