MedSchool: Ace Your OSCEsThe Medical Company
GET - On the App Store
Cranial Nerves
Cranial Nerves

CN II: Optic Nerve

February 15th, 2021


  • Role

  • Special sensory (sight).

Optic Nerve Palsy

  • Abnormalities

  • Loss of visual acuity
  • Visual field loss
  • Loss of light reflexes
  • Loss of accommodation
  • Causes of Optic Nerve Palsy

  • Intraorbital - trauma, ischaemia, aneurysm, tumour, optic neuritis, optic nerve hypoplasia
  • Optic chiasm - pituitary tumour, craniopharyngioma, pituitary apoplexy
  • Optic tract - ischaemia, trauma, tumour, MS

Special Sensory Pathway

Cortical Centre
Primary visual cortex (occipital lobe)
Upper Pathway
Optic radiations
(parietal / occipital lobes)
Lateral geniculate nucleus (thalamus)
Lower Pathway
Optic tract
Partial Decussation
Of nasal / temporal visual field
Optic chiasm
Optic canal
Bipolar Cells
Light Receptors
Rods / cones of retina


The optic nerve is encased in meninges, making it the only cranial nerve that is part of the central nervous system. As a result peripheral neuropathies such as Guillain-barré do not affect the optic nerve.
Next Page
Want more info like this?
  • Your electronic clinical medicine handbook
  • Guides to help pass your exams
  • Tools every medical student needs
  • Quick diagrams to have the answers, fast
  • Quizzes to test your knowledge
Sign Up Now

Snapshot: Initialising...