Optic Neuritis

Essentials of Diagnosis

• Subacute usually unilateral visual loss

• Pain exacerbated by eye movements

• Optic disk usually normal in acute stage but subsequently develops pallor

General Considerations

• Strongly associated with demyelinating disease, particularly multiple sclerosis but also acute disseminated encephalomyelitis

• Also occurs

  • In sarcoidosis

  • In neuromyelitis optica spectrum disorder

  • In association with serum antibodies to myelin oligodendrocyte glycoprotein

  • In children following viral infections

  • In varicella zoster virus infection

  • In various autoimmune disorders, particularly systemic lupus erythematosus and Sjögren syndrome

  • In persons receiving biologics therapy (eg, anti-TNF agents and natalizumab)

  • In spread of inflammation from the meninges, orbital tissues, or paranasal sinuses

• Unilateral loss of vision that usually develops over a few days

• Vision ranges from 20/30 (6/9) to no light perception with more severe visual loss being associated with low serum vitamin D levels

• Pain behind the eye, exacerbated by eye movements

• Field loss is usually a central scotoma, but a wide range of monocular field defects is possible

• Particular loss of color vision

• A relative afferent pupillary defect

• In about two-thirds of cases, the optic nerve is normal during the acute stage (retrobulbar optic neuritis)

• In one-third of cases, the optic disk is swollen (papillitis) with occasional flame-shaped peripapillary hemorrhages

• Visual acuity usually improves within 2–3 weeks and returns to 20/40 (6/12) or better in 95% of previously unaffected eyes

• Optic atrophy develops subsequently if there has been damage to sufficient optic nerve fibers

Imaging Studies

• MRI of the head and orbits should be obtained to exclude a lesion compressing the optic nerve and to identify atypical optic neuritis

  • In patients in whom visual recovery does not occur

  • In patients with other atypical features, including continuing deterioration of vision or persisting pain after 2 weeks

• Intravenous methylprednisolone (1 g daily for 3 days followed by a tapering course of oral prednisolone)

  • Has been shown to accelerate visual recovery, although in clinical practice, the oral taper is not often prescribed and oral methylprednisolone may be used

  • Use in an individual patient is determined by the degree of visual loss, the state of the fellow eye, and the patient's visual requirements

• Phenytoin may be neuroprotective in typical optic neuritis

• Atypical optic neuritis due to sarcoidosis, neuromyelitis optica, herpes zoster, or systemic lupus erythematosus

  • Requires more immediate and prolonged corticosteroid therapy

  • May require plasma exchange

  • May require long-term immunosuppression

Prognosis

• Multiple sclerosis will develop in 50% of patients with clinically isolated optic neuritis

  • The visual and neurologic prognosis is good

  • The major risk factors are female sex and multiple white matter lesions on brain MRI

• Many disease-modifying drugs are available to reduce the risk of further neurologic episodes and potentially the accumulation of disability, but each has adverse effects that in some instances are life-threatening

• Fingolimod is associated with macular edema

• Retinal nerve fiber layer optical coherence tomography quantifies axonal damage that can be used to monitor disease progression

• Optic neuritis due to sarcoidosis, neuromyelitis optica, herpes zoster, or systemic lupus erythematosus generally has a poorer prognosis

When to Refer

• All patients should be referred urgently for ophthalmologic or neurologic assessment