Table 2

Key differences between typical and atypical optic neuritis (ON)

Typical ONAtypical ON
  • Acute to subacute onset promoting over a several hours to 2 weeks

  • Severe visual loss (no light perception) which progress for >2 weeks from onset

  • Young adult patient with peak manifestation between 15 and 50 years of age

  • Age >50 or <12 years

  • Females>males

  • Periocular pain (90%) especially with eye movement

  • Painless/painful/persistent pain >2 weeks

  • Unilateral loss of visual acuity variable in severity (from 20/20 in 10.5% to no light perception in 3.1%) or may be bilateral usually in children often associated with a post or para infectious demyelination

  • Simultaneous or sequential bilateral ON

  • Normal (65%) or swollen (35%) (more common in children) optic nerve head

  • Possibility of mild uveitis and retinal periphlebitis

  • Reduced contrast sensitivity

  • Uhthoff’s phenomenon (exercise or heat-induced deterioration of visual symptoms)

  • Pulfrich phenomenon (misperception of the direction of movement of an object)

  • Abnormal ocular findings including:

  • Noticeable anterior and/or posterior segment inflammation

  • Significant uveitis and retinal periphlebitis

  • Intensely swollen optic nerve head

  • Severe optic disc haemorrhages

  • Retinal exudates

  • Macular star

  • Absence of any visual recovery within 3–5 weeks or continued exacerbation in visual function

  • Previous history of ON or MS

  • Lower risk of developing MS

  • Family history

  • Spontaneous visual improvement in >90%

  • No deterioration in vision after steroids discontinuation

  • Deterioration in vision after steroids discontinuation

  • Poor or no response to treatment with systemic steroids

  • Exquisitely steroid sensitive or steroid dependent optic neuropathy

  • Ipsilateral RAPD. Lack of the defect suggests a preexisting or concurrent optic neuropathy in the fellow eye

  • Visual field defect any type; ranging from commonly seen diffuse depression and central or centrocecal scotoma to rarely seen quadrantic and altitudinal defects

  • Manifestation of systemic diseases other than MS

  • Pallor of the optic disc

  • Optic atrophy lacking history of ON or MS

  • MS, Multiple sclerosis; RAPD, relative afferent pupillary defect.