Last reviewed: March 2026
Contents
MDM Templates
Monocular Diplopia
Patient presents with diplopia that persists when the unaffected eye is covered and resolves when the affected eye is covered alone. This localizes the problem to the affected eye itself rather than to the extraocular muscles or cranial nerves.
Monocular diplopia is not caused by neurologic emergencies. Differential includes refractive error, cataract, corneal irregularity, lens dislocation, and macular pathology. No neurologic deficits on exam.
Plan: No emergent workup indicated.
Disposition: Discharge with ophthalmology follow-up within 1 week. Return precautions for new headache, weakness, or worsening vision.
Binocular Diplopia — Benign / Discharge
Patient presents with binocular diplopia that resolves when either eye is covered. Neurologic exam is nonfocal. Pupils are equal and reactive. No ptosis, no proptosis. Extraocular movements are full or demonstrate an isolated cranial nerve palsy pattern without pupil involvement.
History and exam reassure against stroke, intracranial mass, aneurysm, cavernous sinus thrombosis, orbital entrapment from fracture, myasthenia gravis, and giant cell arteritis. No headache, no jaw claudication, no fatigable weakness, no trauma.
Plan: No emergent imaging indicated based on benign presentation.
Disposition: Discharge with ophthalmology and PCP follow-up within 1 week. Instructed no driving while symptomatic. Return precautions for headache, ptosis, weakness, or worsening diplopia.
Binocular Diplopia — Emergent Workup
Patient presents with binocular diplopia with concerning features: ***. This raises concern for a dangerous intracranial or orbital process.
Given the clinical picture I have considered stroke, posterior communicating artery aneurysm, cavernous sinus thrombosis, intracranial mass, giant cell arteritis, myasthenia gravis, orbital cellulitis, and thyroid eye disease.
Plan: CT/CTA head and neck. Labs including CBC, BMP, ESR, CRP.
If pupil-involving CN III palsy: emergent CTA for aneurysm.
If age >50 with headache, jaw claudication, or elevated ESR/CRP: concern for GCA — ophthalmology and rheumatology consulted.
If fatigable ptosis or weakness: ice test performed, acetylcholine receptor antibodies sent.
Disposition: Pending workup results and consultant recommendations.
Clinical Education
Monocular vs Binocular
The cover test is the single most important exam maneuver. Have the patient cover one eye at a time. If diplopia resolves with either eye covered, it is binocular (misalignment of the two eyes — neurologic or muscular problem). If diplopia persists with one eye covered, it is monocular (intrinsic eye problem — not neurologic). Monocular diplopia is never a neurologic emergency.[1]
Cranial Nerve Palsies
CN VI (abducens) palsy is the most common isolated cranial nerve palsy causing diplopia. Produces horizontal diplopia worse at distance, with limited abduction of the affected eye. Often ischemic in older patients with vascular risk factors. However, CN VI has a long intracranial course and can be a false localizing sign of elevated intracranial pressure.[2]
| Nerve | Deficit | Diplopia Type | Key Concern |
| CN III | “Down and out” + ptosis | Vertical and horizontal | PComm aneurysm (if pupil involved) |
| CN IV | Head tilt, limited downgaze | Vertical (worse looking down) | Often traumatic or congenital |
| CN VI | Limited abduction | Horizontal (worse at distance) | Elevated ICP (false localizing), ischemic |
Dangerous Causes
Red flags that demand emergent imaging: pupil-involving CN III palsy (aneurysm), multiple cranial nerve palsies (cavernous sinus pathology), proptosis with pain (orbital cellulitis, cavernous sinus thrombosis), papilledema (elevated ICP), focal neurologic deficits beyond the eye (stroke), and any diplopia after trauma (orbital fracture with entrapment).[1]
Cavernous sinus thrombosis presents with headache, proptosis, chemosis, ophthalmoplegia (multiple cranial nerve involvement — III, IV, V1, V2, VI), and often fever. Usually a complication of facial or sinus infection. CT venogram or MR venogram is the diagnostic study.[2]
Myasthenia Gravis Pearls
Ocular myasthenia presents with painless, fatigable ptosis and diplopia. Symptoms are worse at the end of the day. The hallmark is fluctuating weakness — the pattern of diplopia may change from visit to visit. The ice test (apply ice to the closed eyelid for 2 minutes — improvement of ptosis by >=2 mm suggests myasthenia) is a useful bedside test with ~80% sensitivity.[3]
If suspected, send acetylcholine receptor antibodies. Consider CT chest (thymoma). Neurology consultation for confirmation and treatment initiation.
Giant Cell Arteritis
In patients >50 with new diplopia, always consider giant cell arteritis. Associated symptoms include new headache, jaw claudication, scalp tenderness, constitutional symptoms, and polymyalgia rheumatica. Diplopia in GCA is caused by ischemia to the extraocular muscles or their nerves. ESR and CRP are the screening labs. If suspicion is high, start empiric prednisone 60–80 mg daily and arrange temporal artery biopsy — do not wait for biopsy results to treat.[4]
Disposition
Monocular diplopia: discharge with ophthalmology follow-up. Isolated CN palsy without red flags in a patient with vascular risk factors: likely ischemic, discharge with neurology and ophthalmology follow-up within 1 week, MRI as outpatient. Any red flags (pupil involvement, multiple CN palsies, proptosis, papilledema, trauma): emergent imaging and consultation in the ED.[1]
References
- Rucker JC. Overview of diplopia. UpToDate. 2024.
- Bhatti MT, Schmalfuss IM. Approach to diplopia in the emergency department. Emerg Med Clin North Am. 2008;26(3):599-628. PubMed
- Golnik KC et al. An ice test for the diagnosis of myasthenia gravis. Ophthalmology. 1999;106(7):1282-1286. PubMed
- Hunder GG et al. The American College of Rheumatology 1990 criteria for the classification of giant cell arteritis. Arthritis Rheum. 1990;33(8):1122-1128. PubMed
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