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What Double Vision Means
Double vision, also called diplopia, means seeing two images of one object instead of a single clear image. The images may appear side by side, one above the other, or slightly offset. Seeing double can be constant or intermittent, and it may happen when you look in a particular direction or use your eyes for a long time.
One-eye double vision
Monocular double vision continues when you cover the other eye and view the object with only one eye. It can be related to the eye surface, cornea, lens, or focusing system.
Two-eye double vision
Binocular double vision occurs when both eyes are open and usually resolves when either eye is covered. It often reflects a problem with eye alignment, eye muscles, nerves, or the way the brain coordinates the eyes.
Emergency Warning Signs
When Double Vision May Be an Emergency
Seek urgent care
Sudden double vision needs prompt assessment
New or sudden double vision can sometimes signal a serious problem. Call emergency services or go to an emergency department, especially if it occurs with any of these warning signs:
- Severe headache, weakness, numbness, facial drooping, trouble speaking, or confusion
- Dizziness, loss of balance, or difficulty walking
- Unequal pupils, vision loss, or significant eye pain
- A recent head injury
Possible Causes
Possible Causes of Double Vision
There are several possible double vision causes. Clinicians consider whether the symptom is monocular or binocular, sudden or gradual, constant or intermittent, and linked with other symptoms. These details help guide the next evaluation, but they do not establish a diagnosis by themselves.
| Possible source | Examples to cover | Pattern or clues to mention |
|---|---|---|
| Cornea or eye surface | Dry eye, corneal irregularity, scarring, or injury | Often monocular; may vary with blinking or irritation |
| Lens | Cataract or lens displacement | Often monocular and may develop gradually |
| Eye alignment or muscles | Strabismus, thyroid eye disease, inflammation, or trauma | Often binocular; may vary with gaze direction |
| Nerves or neuromuscular control | Cranial nerve disorders, myasthenia gravis, diabetes, or high blood pressure | May be intermittent or associated with eyelid or eye-movement changes |
| Brain or blood vessels | Stroke, migraine-related symptoms, multiple sclerosis, or other neurological disorders | Sudden onset or neurological symptoms require urgent assessment |
| Inflammatory conditions | Giant cell arteritis and other inflammatory disorders | May occur with headache, scalp tenderness, jaw pain, or systemic symptoms |
Other possibilities include a glasses prescription change, contact-lens problems, dry eye, cataracts, eye misalignment, migraine, medication effects, or a neurological condition. An eye doctor or another clinician may need to examine the eyes, eye movements, and nervous system to determine what might be causing you to see double.
Relief Tips
What to Do Until You Are Evaluated
- Avoid driving or operating machinery while double vision is present.
- Cover one eye temporarily if this makes walking or other essential tasks safer.
- Sit down if double vision is affecting balance or causing dizziness.
- Record when the symptom began and whether it is constant, intermittent, or linked to a particular gaze.
- Use prescribed glasses as directed, but do not assume new spectacles or eye exercises will treat every cause.
When to See a Doctor
When to See a Doctor for Double Vision
Arrange prompt medical evaluation for new, unexplained, persistent, recurrent, or worsening double vision, even if you have no emergency warning signs. You can start with an eye doctor, optometrist, ophthalmologist, or primary-care clinician, who can coordinate further assessment if needed.
What an evaluation may involve
The evaluation may include a detailed symptom history, testing with each eye covered, checks of eye alignment and movement, and vision and neurological examinations. Depending on your symptoms and examination, the clinician may order selected blood tests or imaging. The urgency and type of referral depend on when the double vision began, whether it is monocular or binocular, associated symptoms, medical conditions, medications, and examination findings.
Complications
Possible Problems Caused by Double Vision
- Persistent double vision can cause eyestrain and headaches.
- Separated images may lead to nausea, dizziness, or difficulty concentrating.
- Impaired depth perception can make stairs, walking, and reaching for objects harder.
- Driving and other visually demanding activities may become unsafe.
- Balance problems and impaired visual judgment can increase the risk of falls or accidents.
These effects are reasons to seek assessment, especially when symptoms persist or interfere with daily activities. Serious complications such as stroke or vision loss would result from an underlying condition rather than from double vision itself.
