Double Vision: Causes, Symptoms, and Treatment Options

Double Vision in Adults: When to See a Doctor

Double vision (diplopia) — seeing two images of a single object — can be sudden or gradual, temporary or persistent. In adults it may signal a benign, easily treatable problem or a serious underlying condition that needs prompt medical attention. This article explains common causes, how to tell when it’s urgent, what to expect during evaluation, and basic treatment options.

What is double vision?

Double vision occurs when the eyes are not aligned or when one eye sends a distorted image to the brain. It can be monocular (persists when one eye is covered) or binocular (resolves when either eye is covered). Binocular diplopia usually indicates a problem with eye movement or nerve control; monocular diplopia typically originates from the eye itself (lens, cornea, tear film, or retina).

Common causes

• Refractive/ocular surface problems: Uncorrected astigmatism, dry eye, cataract, irregular cornea, or lens issues can cause monocular diplopia.
• Extraocular muscle or nerve palsies: Cranial nerve III, IV, or VI palsies, thyroid eye disease, myasthenia gravis, or trauma can produce binocular double vision.
• Neurological conditions: Stroke, brain tumor, aneurysm, multiple sclerosis, or increased intracranial pressure may present with sudden diplopia.
• Systemic illnesses and toxins: Diabetes, hypertension, autoimmune disorders, or certain medications/toxins can cause nerve dysfunction leading to diplopia.
• Infectious or inflammatory causes: Orbital cellulitis, cavernous sinus thrombosis, or inflammatory neuropathies.

Red flags — see a doctor immediately

Seek urgent medical attention (emergency department or same-day ophthalmology/neurology) if double vision is accompanied by any of the following:

• Sudden onset of double vision.
• Weakness, numbness, slurred speech, confusion, severe headache, or difficulty walking (possible stroke).
• Drooping eyelid (ptosis), eye pain particularly with movement, or decreased consciousness.
• Recent head or eye trauma.
• New double vision plus vomiting or visual field loss.
• Symptoms in someone with known vascular risk factors (diabetes, hypertension) or active cancer.

When to make a non-urgent appointment

Book an ophthalmology or neurology appointment within days if you have:

• Gradual onset double vision without red-flag symptoms.
• Double vision that clears when one eye is covered (binocular) but no other neurological signs.
• Monocular diplopia without pain (likely ocular cause such as cataract or corneal irregularity).
• Intermittent diplopia, especially if worse at the end of the day (consider myasthenia gravis).

What to expect during evaluation

1. Medical history: onset, duration, one eye vs both, pattern (horizontal/vertical/diagonal), associated symptoms, medications, systemic diseases.
2. Eye exam: visual acuity, pupillary responses, eyelid position