Diplopia

Basics

Description

  • Double vision:
    • Simultaneous perception of 2 images
    • Can be oriented horizontally, vertically, or diagonally from one another
  • Monocular diplopia: Persists when 1 eye is closed; often due to refractive errors, dry eye, cataracts, or retinal abnormalities
  • Binocular diplopia: Resolves when 1 eye is closed; caused by ocular misalignment
  • Proper alignment is coordinated by the brain’s supranuclear gaze centers
  • The vestibulo-ocular reflex stabilizes retinal images during head movements to maintain clear vision
  • Respective cranial nerve nucleus (midbrain and pons) −> nerve fascicles (including medial longitudinal fasciculus [MLF] and vestibular ocular pathway) traveling through subarachnoid space −> cavernous sinus −> superior orbital fissure −> respective extraocular muscle through neuromuscular junction (NMJ)
  • Ocular movement relies on 6 extraocular muscles controlled by cranial nerves:
    • CN 3 (oculomotor nerve): Superior, inferior, medial rectus, and inferior oblique muscles
    • CN 4 (trochlear nerve): Superior oblique muscle
    • CN 6 (abducens nerve): Lateral rectus

Etiology

  • Monocular diplopia:
    • Nearly always due to an intrinsic eye problem
    • Corneal irregularities (eg, scars, keratoconus)
    • Lenticular abnormalities (eg, cataracts)
    • Retinal pathologies (eg, macular degeneration)
    • Disease affecting the orbits and the bony skull
    • Functional disorders such as conversion disorder, factitious disorder, or somatization
  • Binocular diplopia:
    • Due to misalignment of the eyes, typically caused by dysfunction of the extraocular muscles or the cranial nerves (III, IV, VI)
    • Brainstem lesions
    • Damage to CN nuclei or their connections (include MLF), causing an internuclear ophthalmoplegia (INO):
      • Stroke
      • Multiple sclerosis (MS)
      • Tumors
      • Infections
    • Compressive diplopia:
      • CN dysfunction and denervation caused by compression as they traverse the subarachnoid space and venous sinuses
      • Cavernous sinus thrombosis
      • Aneurysm of posterior communicating artery (CN 3 palsy)
      • Lymphocytic and carcinomatous meningitis (multiple CN deficits)
      • Idiopathic intracranial hypertension (IIH), CN6 palsy
      • Low pressure (Spontaneous intracranial hypotension), CN6 palsy
      • Tumor of the bony skull and orbits
      • Thyroid disease
    • Inflammation:
      • Tolosa–Hunt syndrome
    • NMJ of EOMs
      • Myasthenia gravis (MG)
      • Miller–Fisher syndrome
  • Traumatic diplopia:
    • Can be either monocular or binocular
    • Orbital fracture
    • Contusions
    • Hematoma
    • Rarely brainstem contusion or hematoma

There's more to see -- the rest of this topic is available only to subscribers.

© 2000–2026 Unbound Medicine, Inc. All rights reserved
All content is protected by copyright and may not be used for AI model training or other unauthorized purposes.