What are the symptoms and treatment options for optic neuritis?

Optic Neuritis Symptoms and Treatment

Optic neuritis is an acute inflammatory condition of the optic nerve that typically presents with painful visual loss, which can be unilateral or bilateral, and is often associated with multiple sclerosis or other demyelinating disorders. 1

Clinical Presentation

Primary Symptoms

• Painful visual loss (most common presentation) 1
• Pain with eye movement (characteristic) 1, 2
• Dyschromatopsia (color vision abnormalities) 3
• Visual field defects 2
• Photophobia 1

Visual Disturbances

• Reduced visual acuity (ranging from mild to severe) 2
• Impaired contrast sensitivity (often persists even after recovery) 3
• Central or arcuate visual field defects 1
• Scotomas (blind spots in vision) 1

Associated Findings

• Optic disc edema (present in 30-40% of cases) 1
• Relative afferent pupillary defect (RAPD) in unilateral cases
• Symptoms that outweigh observable signs of disease 1

Differential Diagnosis

Optic neuritis must be differentiated from:

• Multiple sclerosis-associated optic neuritis
• Neuromyelitis optica (NMO) and NMO spectrum disorders 1
• Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease 2
• Anterior ischemic optic neuropathy (AION) 3
• Leber's hereditary optic neuropathy 3
• Neuropathic ocular pain 1
• Infectious or granulomatous conditions 1

Diagnostic Evaluation

Imaging Studies

• MRI of orbits and brain with and without contrast is the primary imaging study for initial assessment 1, 4
  • Evaluates for abnormal enhancement and signal changes within the optic nerve
  • Detects associated intracranial demyelinating lesions (strong predictor of MS development) 4
  • Helps establish dissemination of lesions in space and time (McDonald criteria) 1, 4

Additional Testing

• Visual evoked potentials (VEP) to detect bilateral optic nerve damage 1
• Fluoroangiography when vaso-occlusive retinopathy is suspected 1
• Serum NMO IgG (aquaporin) antibodies to diagnose co-existing neuromyelitis optica 1
• CSF analysis to exclude infectious causes and evaluate for oligoclonal bands 1, 2

Treatment Approaches

Acute Management

• High-dose intravenous methylprednisolone is the first-line treatment for optic neuritis, providing faster visual recovery though not affecting final visual outcome 5, 3, 6
  • Typical regimen: 1 gram/day for 3-5 days 7
  • Speeds recovery of vision but does not affect final visual outcome 5, 6
  • May delay progression to clinically definite MS at 2 years (but not at 5 or 10 years) 6

Important Cautions

• Oral prednisolone alone is contraindicated due to increased risk of recurrence 3
• High-dose IV methylprednisolone can rarely cause toxic hepatitis 7
• Corticosteroids should be used cautiously in patients with ocular herpes simplex 7
• Corticosteroids are not recommended for use in active ocular herpes simplex 7

Additional Treatment Options

• Plasma exchange therapy may be considered in severe cases 1
• For cases associated with NMO or MOG antibody disease, more aggressive immunosuppression may be needed 2
• Interferon β-1a,b has been shown to reduce risk of MS development in high-risk patients 3

Prognosis and Follow-up

• Most patients with typical optic neuritis have good recovery of high-contrast visual acuity 2

• Residual deficits often persist in:

  • Contrast sensitivity
  • Color vision
  • Visual fields
  • Binocular vision
  • Motion perception 3, 2

• Poorer visual outcomes are associated with:

  • Antibodies to MOG, AQP4, or CRMP5 2
  • Extensive MRI lesions 1
  • Reduced muscle strength or sphincter dysfunction at presentation 1
  • Delay (>2 weeks) in treatment initiation 1

Special Considerations

• Optic neuritis is often the initial manifestation of multiple sclerosis 1, 8
• The presence of multiple brain lesions on initial MRI significantly increases the risk of developing clinically definite MS 4
• Patients with optic neuritis should be monitored for development of other neurological symptoms that may indicate MS progression

Early diagnosis and prompt treatment with high-dose intravenous corticosteroids are essential for optimizing visual outcomes and potentially delaying progression to multiple sclerosis in susceptible individuals.