Diplopia

Background
Eye movements by extra-ocular muscles and cranial nerve innervation

Monocular Diplopia
  • Double vision that persists when one eye is closed
  • Related to intrinsic eye problem[1]

Binocular Diplopia
  • Double vision that resolves when the other eye is closed
  • Related to a problem with visual axis alignment[2]

3 Main Causes Binocular Diplopia

Clinical Features

Exam
  • Determine monocular vs binocular
  • Evaluate for visual field defects
  • Evaluate visual acuity
  • Assess cranial nerves
  • Check extraocular muscle function
    • Entrapment will show extraocular muscle restriction with extremes of gaze
  • Sudden painful or non painful onset suggest a vascular cause such as thrombosis, dissection, ischemia, or vasculitis
  • Other neuro deficits should raise suspicion for a CVA or MS
  • Systemic illness is more likely with meningitis involving the brainstem
  • Bilateral symptoms are more likely with neuromuscular problems such as Miller Fischer syndrome, botulism, or myasthenia gravis

Differential Diagnosis
Algorithm for the Evaluation of Diplopia

Monocular Diplopia

Binocular Diplopia

Evaluation

Monocular

Binocular
  • Third nerve palsy: eye is down and out
    • Always needs CTH/CTA to rule out [[Posterior Communicating Artery (PCOM) Aneurysm|aneurysm given that nerve runs under PCA
  • Fourth nerve palsy: head tilt down and away from side of lesion
    • These are tough to catch and can be referred to ophtho outpatient for prisms
    • No imaging needed unless other deficits present
  • Sixth nerve palsy: eye can't track laterally
    • Children need imaging to r/o tumor
    • In > 50, m/l ischemic and can get MRI outpt or just watch, assuming no papilledema as it can cause isolated CN VI palsy
    • If other nerves/deficits noted, consider MRI and further wu
  • Other potential studies also include:
    • CTH with and without contrast ± CTA neck to rule out dissection and intracranial mass
    • MRV or CTV to eval for cavernous sinus thrombosis
    • CT orbits w/ contrast to eval for orbital apex syndrome (like CST above, but with CN II involvement)
    • MRI + DWI to if concern for CVA
    • MRI ± MRA if unable to classify intracranial process on initial contrast CT with contrast
    • MRI if concerned for MS
    • LP if concern for meningitis
    • Metabolic workup to rule out diabetes or cause of mononeuropathy

Management
  • Treat underlying cause
  • Neurology or neurosurgical consult is warranted if evidence of an ICH, aneurysm or CVA

Disposition
  • Depends greatly on the cause of the diplopia
  • Admit if:
  • Isolated Cranial Nerve III and VI palsy can be discharge if close neurology follow-up and cause due to diabetes, microvascular ischemia and intracranial process ruled out[5]

See Also

References
  1. Coffeen P, Guyton DL: Monocular diplopia accompanying ordinary refractive errors. Am J Ophthalmol 1988; 105:451
  2. Rucker JC, Tomsak RL: Binocular diplopia. A practical approach. Neurologist 2005; 11:98-110
  3. Kusner LL, Puwanant A, Kaminski HJ: Ocular myasthenia: Diagnosis, treatment, and pathogenesis. Neurologist 2006; 12:231-239
  4. Bushra JS: Miller Fisher syndrome: An uncommon acute neuropathy. J Emerg Med 2000; 18:427-430
  5. Sanders SK, Kawasaki A, Purvin VA: Long-term prognosis in patients with vasculopathic sixth nerve palsy. Am J Ophthalmol 2002; 134:81-84
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