What are the symptoms and treatment options for diplopia (double vision)?

Diplopia: Symptoms and Treatment

Diplopia (double vision) is the perception of two images of a single object, which can be monocular (persists with one eye closed) or binocular (resolves with one eye closed), with binocular diplopia most commonly resulting from ocular misalignment due to neurologic or orbital causes requiring urgent evaluation to exclude life-threatening conditions. 1, 2, 3

Symptoms and Clinical Presentation

Binocular Diplopia

• Images separate when both eyes are open but resolve when either eye is closed, indicating misalignment of the visual axes preventing images from falling on corresponding retinal points 1
• Diplopia may be horizontal, vertical, or oblique in orientation 3
• Worsening with fatigue and improvement with rest suggests myasthenia gravis 4
• Distance-worse diplopia occurs with divergence insufficiency or sagging eye syndrome (typically after age 50-70 years) 5
• Associated symptoms requiring urgent attention include:
  • Headache, pupillary abnormalities, or ptosis (suggest compressive lesion or aneurysm) 4, 6, 3
  • Brainstem symptoms (vertigo, ataxia, dysarthria) 6
  • Bradycardia, nausea, or loss of consciousness with orbital trauma (oculocardiac reflex) 5

Monocular Diplopia

• Diplopia persists with the affected eye open and the other eye closed, typically indicating intraocular pathology (refractive errors, cataracts, dry eye, retinal disease) rather than neurologic causes 1, 7
• Can rarely occur with increased intracranial pressure or papilledema 1, 7

Diagnostic Approach

History and Examination Priorities

• Determine if diplopia is monocular or binocular by having the patient cover each eye alternately 1, 6
• Document onset timing (sudden onset requires urgent evaluation), pattern (constant vs. intermittent), and gaze positions affected 5, 3
• Perform detailed sensorimotor examination including versions, ductions, saccades, pursuit, vergence, alignment in multiple gaze positions, and forced duction testing 5
• Check for pupillary involvement (pupil-involving third nerve palsy mandates urgent aneurysm evaluation) 4, 6
• Assess for ptosis, proptosis, facial sensation, and exophthalmometry 5
• Ice pack test: apply ice over closed eyes for 5 minutes—improvement of ptosis or strabismus is highly specific for myasthenia gravis 4

Urgent Imaging Indications

• All third nerve palsies require urgent CTA or MRA to exclude posterior communicating artery aneurysm 4, 6
• Acute binocular diplopia with brainstem symptoms requires urgent brain MRI 6
• Headache or pupillary involvement necessitates same-day urgent imaging 3
• Multiple ipsilateral cranial nerve palsies (III, IV, VI) suggest cavernous sinus or orbital apex lesions requiring MRI with contrast 4, 6
• Orbital trauma requires CT imaging (not MRI if metallic foreign body possible) to assess for fractures, muscle entrapment, or hemorrhage 5

Sixth Nerve Palsy Management Controversy

• Patients over 50 years with microvascular risk factors may be observed for 2-3 months as microvascular sixth nerve palsy typically resolves spontaneously 6
• All other sixth nerve palsy patients require brain MRI with contrast at presentation 6

Laboratory and Additional Testing

• Acetylcholine receptor antibodies (80-88% sensitivity, 98-100% specificity for myasthenia gravis) 4
• Anti-MuSK antibodies if acetylcholine receptor antibodies negative (positive in one-third of seronegative patients) 4
• Chest CT to screen for thymoma in suspected myasthenia (10-15% have thymoma) 4
• Thyroid function tests for thyroid eye disease evaluation 5, 4
• Consider syphilis and Lyme serology with lumbar puncture if indicated 4

Treatment Options

Observation

• Microvascular cranial nerve palsies in patients over 50 with vascular risk factors typically resolve spontaneously within 6 months 5, 6, 3
• Post-traumatic diplopia that persists beyond 6 months is unlikely to resolve without intervention 5

Non-Surgical Management

Prism Correction

• Fresnel or ground-in prisms provide temporary or permanent relief for small to moderate deviations 5
• Useful while awaiting spontaneous resolution or as definitive treatment for residual post-surgical deviations 5

Fogging Techniques

• Bangerter foils or Scotch Satin tape applied to spectacle lens creates central scotoma, eliminating foveal conflict 5
• Occlusive contact lenses may be better tolerated than tape 5
• Most suitable long-term solution for binocular central diplopia that doesn't respond to other treatments 5

Botulinum Toxin

• Chemodenervation can provide temporary relief during active thyroid eye disease or after surgical failure 5
• May reduce misalignment during the inflammatory phase of thyroid orbitopathy 5

Refractive Correction

• Correct hyperopia and provide appropriate bifocals/progressive lenses for presbyopic adults 5
• Reverse monovision if present, as this may resolve symptoms 5

Surgical Management

Timing Considerations

• Thyroid eye disease: delay surgery until disease quiescent for 6 months and angle stable, though earlier surgery in select cases can be successful 5
• Orbital trauma: typically wait 6 months for spontaneous resolution before surgery 5
• Orbital decompression must precede strabismus surgery in thyroid patients, as decompression significantly alters alignment 5

Surgical Approach

• Recession of restricted muscles is the mainstay for restrictive strabismus (thyroid eye disease, orbital trauma) 5
• Resection generally avoided in restrictive disease but can be useful adjunct in select cases 5
• Advancement of previously recessed medial rectus muscles for consecutive exotropia with adduction deficits 5
• Success rates: horizontal deviations 84% vs. vertical deviations 66% after primary surgery in thyroid patients 5

Surgical Complications

• Persistent diplopia occurs in <1% after successful surgery for childhood-onset strabismus in adults 5
• Globe perforation (0.08%-5.1%), most without sequelae but increased retinal detachment risk 5
• Pulled-in-two syndrome (1 in 14,000, more common in adults and thyroid patients) 5
• Anterior segment ischemia (1 in 6,000, higher risk with age, vascular factors, operating on ≥3 muscles) 5

Disease-Specific Treatments

Myasthenia Gravis

• Acetylcholinesterase inhibitors (pyridostigmine) for symptomatic relief 4
• Immunosuppression and thymectomy as indicated 4
• Monitor respiratory function immediately as myasthenic crisis is life-threatening 4

Thyroid Eye Disease

• Teprotumumab shows encouraging outcomes but has significant adverse effects (hyperglycemia, hearing impairment, contraindicated in pregnancy and inflammatory bowel disease) 5
• High-dose pulse steroids or orbital radiation for compressive optic neuropathy 5
• Orbital decompression for severe proptosis or optic nerve compression, performed before strabismus surgery 5

Critical Pitfalls to Avoid

• Never assume pupil-sparing indicates benign microvascular disease when ophthalmoplegia is complete or bilateral—compressive lesions can present this way 4
• Do not delay imaging for third nerve palsy regardless of pupil involvement—all require urgent vascular imaging 4, 6
• Monocular diplopia patients with full ocular motility should be referred to ophthalmology, not pursued with neuroimaging 6
• Orbital trauma with bradycardia/nausea indicates oculocardiac reflex from muscle entrapment—this is life-threatening and requires urgent surgical intervention 5
• Prism testing response can be misleading in adult patients with childhood-onset strabismus due to anomalous retinal correspondence, but postoperative diplopia remains rare (<1%) 5