Optic Atrophy

When is it optic atrophy?

The optic nerve comprises of 1.2 million myelinated axons. Once damaged, the axons do not regenerate (behaves more like a white matter tract than a true peripheral nerve). Thus optic atrophy is the common morphological endpoint of any optic neuropathy. Clinically, the neuro-retinal rim of the optic disc (the area excluding the cup) appears pale/yellow, with associated visual impairment. This is different to glaucoma, where the disease is characterized by an increased cup to disc ratio but the neuro-retinal rim remains pink. Optic atrophy is a clinical diagnosis and does not carry any implications on the underlying cause.

Causes of optic atrophy:

  • Compressive optic neuropathy (papilloedema, tumors, thyroid eye disease)
  • Ischaemic optic neuropathy (arteritic or non-arteritic, diabetes)
  • Optic neuritis (infectious or inflammatory)
  • Nutritional Deficiencies (vitamin B12 and folate deficiencies)
  • Toxic optic neuropathy (ethambutol toxicity, common in Hong Kong due to pulmonary tuberculosis being endemic in this locality)
  • Infiltrative diseases (leukemia, sarcoidosis)
  • Hereditary opic neuropathies (autosomal dominant, mitochondrial)
  • Iatrogenic – Radiation optic neuropathies (common in Hong Kong, due a high incidence of nasopharyngeal carcinoma, and the primary treatment being radiotherapy)
  • Traumatic
  • Glaucomatous optic neuropathy / glaucoma – optic atrophy in end-stage disease

Workup considerations of optic atrophy to dertermine the underlying cause:

  • Medical and family history
  • Visual acuity
  • Intraocular pressure
  • Pupillary reflexes
  • Colour vision
  • Visual field testing
  • Neuroimaging
  • Blood tests (vitamin B12, folate, VDRL, ANA)

Welcome to the HKU eLearning Platform in Clinical Neurosciences!

If this is the first time you have accessed the platform, we would be most grateful if you could let us know a little bit about you.


What is your occupation?




Medical doctor




How did you hear about this platform?