Eye movements by extra-ocular muscles and cranial nerve innervation
Right eye

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


Differential Diagnosis

Algorithm for the Evaluation of Diplopia

Monocular Diplopia

Binocular Diplopia




  • 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

Imaging Guide

Clinical Situation Suspected Diagnosis Imaging Study
Diplopia & cerebellar signs and symptoms Brainstem pathology MRI brain
6th CN palsy & papilledema IIH or CVT CT/CTV brain
3rd CN palsy PCA or ICA aneurysmCompressive lesion CT/CTA brain
Diplopia & thyroid disease & decreased visual acuity Optic nerve compression CT orbits
Intranuclear ophthalmoplegia Multiple sclerosis MRI brain
Diplopia & trauma Fracture causing CN disruption CT head without contrast
Diplopia & multiple CN involvement & numbness over CN5 (Unilateral, decreased visual acuity) Orbital apex pathology CT orbits with contrast
Diplopia & multiple CN involvement & numbness over CN5 (Uni- or bilateral, normal visual acuity) Cavernous sinus thrombosis CT/CTV brain


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


  • 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

External Links


  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